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This is Info file slib.info, produced by Makeinfo version 1.68 from the input file slib.texi. INFO-DIR-SECTION The Algorithmic Language Scheme START-INFO-DIR-ENTRY * SLIB: (slib). Scheme Library END-INFO-DIR-ENTRY This file documents SLIB, the portable Scheme library. Copyright (C) 1993 Todd R. Eigenschink Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998 Aubrey Jaffer Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that this permission notice may be stated in a translation approved by the author. File: slib.info, Node: Top, Next: The Library System, Prev: (dir), Up: (dir) "SLIB" is a portable library for the programming language "Scheme". It provides a platform independent framework for using "packages" of Scheme procedures and syntax. As distributed, SLIB contains useful packages for all implementations. Its catalog can be transparently extended to accomodate packages specific to a site, implementation, user, or directory. Aubrey Jaffer <jaffer @ ai.mit.edu> Hyperactive Software - The Maniac Inside! `http://swissnet.ai.mit.edu/~jaffer/SLIB.html' * Menu: * The Library System:: How to use and customize. * Scheme Syntax Extension Packages:: * Textual Conversion Packages:: * Mathematical Packages:: * Database Packages:: * Other Packages:: * About SLIB:: Install, etc. * Index:: File: slib.info, Node: The Library System, Next: Scheme Syntax Extension Packages, Prev: Top, Up: Top The Library System ****************** * Menu: * Feature:: SLIB names. * Requesting Features:: * Library Catalogs:: * Catalog Compilation:: * Built-in Support:: * About this manual:: File: slib.info, Node: Feature, Next: Requesting Features, Prev: The Library System, Up: The Library System Feature ======= SLIB denotes "features" by symbols. SLIB maintains a list of features supported by the Scheme "session". The set of features provided by a session may change over time. Some features are properties of the Scheme implementation being used. The following features detail what sort of numbers are available from an implementation. * 'inexact * 'rational * 'real * 'complex * 'bignum Other features correspond to the presence of sets of Scheme procedures or syntax (macros). - Function: provided? FEATURE Returns `#t' if FEATURE is supported by the current Scheme session. - Procedure: provide FEATURE Informs SLIB that FEATURE is supported. Henceforth `(provided? FEATURE)' will return `#t'. (provided? 'foo) => #f (provide 'foo) (provided? 'foo) => #t File: slib.info, Node: Requesting Features, Next: Library Catalogs, Prev: Feature, Up: The Library System Requesting Features =================== SLIB creates and maintains a "catalog" mapping features to locations of files introducing procedures and syntax denoted by those features. At the beginning of each section of this manual, there is a line like `(require 'FEATURE)'. The Scheme files comprising SLIB are cataloged so that these feature names map to the corresponding files. SLIB provides a form, `require', which loads the files providing the requested feature. - Procedure: require FEATURE * If `(provided? FEATURE)' is true, then `require' just returns an unspecified value. * Otherwise, if FEATURE is found in the catalog, then the corresponding files will be loaded and an unspecified value returned. Subsequently `(provided? FEATURE)' will return `#t'. * Otherwise (FEATURE not found in the catalog), an error is signaled. The catalog can also be queried using `require:feature->path'. - Function: require:feature->path FEATURE * If FEATURE is already provided, then returns `#t'. * Otherwise, if FEATURE is in the catalog, the path or list of paths associated with FEATURE is returned. * Otherwise, returns `#f'. File: slib.info, Node: Library Catalogs, Next: Catalog Compilation, Prev: Requesting Features, Up: The Library System Library Catalogs ================ At the start of a session no catalog is present, but is created with the first catalog inquiry (such as `(require 'random)'). Several sources of catalog information are combined to produce the catalog: * standard SLIB packages. * additional packages of interest to this site. * packages specifically for the variety of Scheme which this session is running. * packages this user wants to always have available. This catalog is the file `homecat' in the user's "HOME" directory. * packages germane to working in this (current working) directory. This catalog is the file `usercat' in the directory to which it applies. One would typically `cd' to this directory before starting the Scheme session. Catalog files consist of one or more "association list"s. In the circumstance where a feature symbol appears in more than one list, the latter list's association is retrieved. Here are the supported formats for elements of catalog lists: `(FEATURE . <symbol>)' Redirects to the feature named <symbol>. `(FEATURE . "<path>")' Loads file <path>. `(FEATURE source "<path>")' `slib:load's the Scheme source file <path>. `(FEATURE compiled "<path>" ...)' `slib:load-compiled's the files <path> .... The various macro styles first `require' the named macro package, then just load <path> or load-and-macro-expand <path> as appropriate for the implementation. `(FEATURE defmacro "<path>")' `defmacro:load's the Scheme source file <path>. `(FEATURE macro-by-example "<path>")' `defmacro:load's the Scheme source file <path>. `(FEATURE macro "<path>")' `macro:load's the Scheme source file <path>. `(FEATURE macros-that-work "<path>")' `macro:load's the Scheme source file <path>. `(FEATURE syntax-case "<path>")' `macro:load's the Scheme source file <path>. `(FEATURE syntactic-closures "<path>")' `macro:load's the Scheme source file <path>. Here is an example of a `usercat' catalog. A Program in this directory can invoke the `run' feature with `(require 'run)'. ;;; "usercat": SLIB catalog additions for SIMSYNCH. -*-scheme-*- ( (simsynch . "../synch/simsynch.scm") (run . "../synch/run.scm") (schlep . "schlep.scm") ) File: slib.info, Node: Catalog Compilation, Next: Built-in Support, Prev: Library Catalogs, Up: The Library System Catalog Compilation =================== SLIB combines the catalog information which doesn't vary per user into the file `slibcat' in the implementation-vicinity. Therefore `slibcat' needs change only when new software is installed or compiled. Because the actual pathnames of files can differ from installation to installation, SLIB builds a separate catalog for each implementation it is used with. The definition of `*SLIB-VERSION*' in SLIB file `require.scm' is checked against the catalog association of `*SLIB-VERSION*' to ascertain when versions have changed. I recommend that the definition of `*SLIB-VERSION*' be changed whenever the library is changed. If multiple implementations of Scheme use SLIB, remember that recompiling one `slibcat' will fix only that implementation's catalog. The compilation scripts of Scheme implementations which work with SLIB can automatically trigger catalog compilation by deleting `slibcat' or by invoking a special form of `require': - Procedure: require 'new-catalog This will load `mklibcat', which compiles and writes a new `slibcat'. Another special form of `require' erases SLIB's catalog, forcing it to be reloaded the next time the catalog is queried. - Procedure: require #f Removes SLIB's catalog information. This should be done before saving an executable image so that, when restored, its catalog will be loaded afresh. Each file in the table below is descibed in terms of its file-system independent "vicinity" (*note Vicinity::.). The entries of a catalog in the table override those of catalogs above it in the table. `implementation-vicinity' `slibcat' This file contains the associations for the packages comprising SLIB, the `implcat' and the `sitecat's. The associations in the other catalogs override those of the standard catalog. `library-vicinity' `mklibcat.scm' creates `slibcat'. `library-vicinity' `sitecat' This file contains the associations specific to an SLIB installation. `implementation-vicinity' `implcat' This file contains the associations specific to an implementation of Scheme. Different implementations of Scheme should have different `implementation-vicinity'. `implementation-vicinity' `mkimpcat.scm' if present, creates `implcat'. `implementation-vicinity' `sitecat' This file contains the associations specific to a Scheme implementation installation. `home-vicinity' `homecat' This file contains the associations specific to an SLIB user. `user-vicinity' `usercat' This file contains associations effecting only those sessions whose "working directory" is `user-vicinity'. File: slib.info, Node: Built-in Support, Next: About this manual, Prev: Catalog Compilation, Up: The Library System Built-in Support ================ The procedures described in these sections are supported by all implementations as part of the `*.init' files or by `require.scm'. * Menu: * Require:: Module Management * Vicinity:: Pathname Management * Configuration:: Characteristics of Scheme Implementation * Input/Output:: Things not provided by the Scheme specs. * Legacy:: * System:: LOADing, EVALing, ERRORing, and EXITing File: slib.info, Node: Require, Next: Vicinity, Prev: Built-in Support, Up: Built-in Support Require ------- - Variable: *features* Is a list of symbols denoting features supported in this implementation. *FEATURES* can grow as modules are `require'd. *FEATURES* must be defined by all implementations (*note Porting::.). Here are features which SLIB (`require.scm') adds to *FEATURES* when appropriate. * 'inexact * 'rational * 'real * 'complex * 'bignum For each item, `(provided? 'FEATURE)' will return `#t' if that feature is available, and `#f' if not. - Variable: *modules* Is a list of pathnames denoting files which have been loaded. - Variable: *catalog* Is an association list of features (symbols) and pathnames which will supply those features. The pathname can be either a string or a pair. If pathname is a pair then the first element should be a macro feature symbol, `source', or `compiled'. The cdr of the pathname should be either a string or a list. In the following functions if the argument FEATURE is not a symbol it is assumed to be a pathname. - Function: provided? FEATURE Returns `#t' if FEATURE is a member of `*features*' or `*modules*' or if FEATURE is supported by a file already loaded and `#f' otherwise. - Procedure: require FEATURE FEATURE is a symbol. If `(provided? FEATURE)' is true `require' returns. Otherwise, if `(assq FEATURE *catalog*)' is not `#f', the associated files will be loaded and `(provided? FEATURE)' will henceforth return `#t'. An unspecified value is returned. If FEATURE is not found in `*catalog*', then an error is signaled. - Procedure: require PATHNAME PATHNAME is a string. If PATHNAME has not already been given as an argument to `require', PATHNAME is loaded. An unspecified value is returned. - Procedure: provide FEATURE Assures that FEATURE is contained in `*features*' if FEATURE is a symbol and `*modules*' otherwise. - Function: require:feature->path FEATURE Returns `#t' if FEATURE is a member of `*features*' or `*modules*' or if FEATURE is supported by a file already loaded. Returns a path if one was found in `*catalog*' under the feature name, and `#f' otherwise. The path can either be a string suitable as an argument to load or a pair as described above for *catalog*. File: slib.info, Node: Vicinity, Next: Configuration, Prev: Require, Up: Built-in Support Vicinity -------- A vicinity is a descriptor for a place in the file system. Vicinities hide from the programmer the concepts of host, volume, directory, and version. Vicinities express only the concept of a file environment where a file name can be resolved to a file in a system independent manner. Vicinities can even be used on "flat" file systems (which have no directory structure) by having the vicinity express constraints on the file name. On most systems a vicinity would be a string. All of these procedures are file system dependent. These procedures are provided by all implementations. - Function: make-vicinity PATH Returns the vicinity of PATH for use by `in-vicinity'. - Function: program-vicinity Returns the vicinity of the currently loading Scheme code. For an interpreter this would be the directory containing source code. For a compiled system (with multiple files) this would be the directory where the object or executable files are. If no file is currently loading it the result is undefined. *Warning:* `program-vicinity' can return incorrect values if your program escapes back into a `load'. - Function: library-vicinity Returns the vicinity of the shared Scheme library. - Function: implementation-vicinity Returns the vicinity of the underlying Scheme implementation. This vicinity will likely contain startup code and messages and a compiler. - Function: user-vicinity Returns the vicinity of the current directory of the user. On most systems this is `""' (the empty string). - Function: home-vicinity Returns the vicinity of the user's "HOME" directory, the directory which typically contains files which customize a computer environment for a user. If scheme is running without a user (eg. a daemon) or if this concept is meaningless for the platform, then `home-vicinity' returns `#f'. - Function: in-vicinity VICINITY FILENAME Returns a filename suitable for use by `slib:load', `slib:load-source', `slib:load-compiled', `open-input-file', `open-output-file', etc. The returned filename is FILENAME in VICINITY. `in-vicinity' should allow FILENAME to override VICINITY when FILENAME is an absolute pathname and VICINITY is equal to the value of `(user-vicinity)'. The behavior of `in-vicinity' when FILENAME is absolute and VICINITY is not equal to the value of `(user-vicinity)' is unspecified. For most systems `in-vicinity' can be `string-append'. - Function: sub-vicinity VICINITY NAME Returns the vicinity of VICINITY restricted to NAME. This is used for large systems where names of files in subsystems could conflict. On systems with directory structure `sub-vicinity' will return a pathname of the subdirectory NAME of VICINITY. File: slib.info, Node: Configuration, Next: Input/Output, Prev: Vicinity, Up: Built-in Support Configuration ------------- These constants and procedures describe characteristics of the Scheme and underlying operating system. They are provided by all implementations. - Constant: char-code-limit An integer 1 larger that the largest value which can be returned by `char->integer'. - Constant: most-positive-fixnum In implementations which support integers of practically unlimited size, MOST-POSITIVE-FIXNUM is a large exact integer within the range of exact integers that may result from computing the length of a list, vector, or string. In implementations which do not support integers of practically unlimited size, MOST-POSITIVE-FIXNUM is the largest exact integer that may result from computing the length of a list, vector, or string. - Constant: slib:tab The tab character. - Constant: slib:form-feed The form-feed character. - Function: software-type Returns a symbol denoting the generic operating system type. For instance, `unix', `vms', `macos', `amiga', or `ms-dos'. - Function: slib:report-version Displays the versions of SLIB and the underlying Scheme implementation and the name of the operating system. An unspecified value is returned. (slib:report-version) => slib "2c5" on scm "5b1" on unix | - Function: slib:report Displays the information of `(slib:report-version)' followed by almost all the information neccessary for submitting a problem report. An unspecified value is returned. - Function: slib:report #T provides a more verbose listing. - Function: slib:report FILENAME Writes the report to file `filename'. (slib:report) => slib "2c5" on scm "5b1" on unix | (implementation-vicinity) is "/home/jaffer/scm/" (library-vicinity) is "/home/jaffer/slib/" (scheme-file-suffix) is ".scm" loaded *features* : trace alist qp sort common-list-functions macro values getopt compiled implementation *features* : bignum complex real rational inexact vicinity ed getenv tmpnam abort transcript with-file ieee-p1178 rev4-report rev4-optional-procedures hash object-hash delay eval dynamic-wind multiarg-apply multiarg/and- logical defmacro string-port source current-time record rev3-procedures rev2-procedures sun-dl string-case array dump char-ready? full-continuation system implementation *catalog* : (i/o-extensions compiled "/home/jaffer/scm/ioext.so") ... File: slib.info, Node: Input/Output, Next: Legacy, Prev: Configuration, Up: Built-in Support Input/Output ------------ These procedures are provided by all implementations. - Procedure: file-exists? FILENAME Returns `#t' if the specified file exists. Otherwise, returns `#f'. If the underlying implementation does not support this feature then `#f' is always returned. - Procedure: delete-file FILENAME Deletes the file specified by FILENAME. If FILENAME can not be deleted, `#f' is returned. Otherwise, `#t' is returned. - Procedure: tmpnam Returns a pathname for a file which will likely not be used by any other process. Successive calls to `(tmpnam)' will return different pathnames. - Procedure: current-error-port Returns the current port to which diagnostic and error output is directed. - Procedure: force-output - Procedure: force-output PORT Forces any pending output on PORT to be delivered to the output device and returns an unspecified value. The PORT argument may be omitted, in which case it defaults to the value returned by `(current-output-port)'. - Procedure: output-port-width - Procedure: output-port-width PORT Returns the width of PORT, which defaults to `(current-output-port)' if absent. If the width cannot be determined 79 is returned. - Procedure: output-port-height - Procedure: output-port-height PORT Returns the height of PORT, which defaults to `(current-output-port)' if absent. If the height cannot be determined 24 is returned. File: slib.info, Node: Legacy, Next: System, Prev: Input/Output, Up: Built-in Support Legacy ------ These procedures are provided by all implementations. - Function: identity X IDENTITY returns its argument. Example: (identity 3) => 3 (identity '(foo bar)) => (foo bar) (map identity LST) == (copy-list LST) The following procedures were present in Scheme until R4RS (*note Language changes: (r4rs)Notes.). They are provided by all SLIB implementations. - Constant: t Derfined as `#t'. - Constant: nil Defined as `#f'. - Function: last-pair L Returns the last pair in the list L. Example: (last-pair (cons 1 2)) => (1 . 2) (last-pair '(1 2)) => (2) == (cons 2 '()) File: slib.info, Node: System, Prev: Legacy, Up: Built-in Support System ------ These procedures are provided by all implementations. - Procedure: slib:load-source NAME Loads a file of Scheme source code from NAME with the default filename extension used in SLIB. For instance if the filename extension used in SLIB is `.scm' then `(slib:load-source "foo")' will load from file `foo.scm'. - Procedure: slib:load-compiled NAME On implementations which support separtely loadable compiled modules, loads a file of compiled code from NAME with the implementation's filename extension for compiled code appended. - Procedure: slib:load NAME Loads a file of Scheme source or compiled code from NAME with the appropriate suffixes appended. If both source and compiled code are present with the appropriate names then the implementation will load just one. It is up to the implementation to choose which one will be loaded. If an implementation does not support compiled code then `slib:load' will be identical to `slib:load-source'. - Procedure: slib:eval OBJ `eval' returns the value of OBJ evaluated in the current top level environment. *Note Eval:: provides a more general evaluation facility. - Procedure: slib:eval-load FILENAME EVAL FILENAME should be a string. If filename names an existing file, the Scheme source code expressions and definitions are read from the file and EVAL called with them sequentially. The `slib:eval-load' procedure does not affect the values returned by `current-input-port' and `current-output-port'. - Procedure: slib:warn ARG1 ARG2 ... Outputs a warning message containing the arguments. - Procedure: slib:error ARG1 ARG2 ... Outputs an error message containing the arguments, aborts evaluation of the current form and responds in a system dependent way to the error. Typical responses are to abort the program or to enter a read-eval-print loop. - Procedure: slib:exit N - Procedure: slib:exit Exits from the Scheme session returning status N to the system. If N is omitted or `#t', a success status is returned to the system (if possible). If N is `#f' a failure is returned to the system (if possible). If N is an integer, then N is returned to the system (if possible). If the Scheme session cannot exit an unspecified value is returned from `slib:exit'. File: slib.info, Node: About this manual, Prev: Built-in Support, Up: The Library System About this manual ================= * Entries that are labeled as Functions are called for their return values. Entries that are labeled as Procedures are called primarily for their side effects. * Examples in this text were produced using the `scm' Scheme implementation. * At the beginning of each section, there is a line that looks like `(require 'feature)'. Include this line in your code prior to using the package. File: slib.info, Node: Scheme Syntax Extension Packages, Next: Textual Conversion Packages, Prev: The Library System, Up: Top Scheme Syntax Extension Packages ******************************** * Menu: * Defmacro:: Supported by all implementations * R4RS Macros:: 'macro * Macro by Example:: 'macro-by-example * Macros That Work:: 'macros-that-work * Syntactic Closures:: 'syntactic-closures * Syntax-Case Macros:: 'syntax-case Syntax extensions (macros) included with SLIB. Also *Note Structures::. * Fluid-Let:: 'fluid-let * Yasos:: 'yasos, 'oop, 'collect File: slib.info, Node: Defmacro, Next: R4RS Macros, Prev: Scheme Syntax Extension Packages, Up: Scheme Syntax Extension Packages Defmacro ======== Defmacros are supported by all implementations. - Function: gentemp Returns a new (interned) symbol each time it is called. The symbol names are implementation-dependent (gentemp) => scm:G0 (gentemp) => scm:G1 - Function: defmacro:eval E Returns the `slib:eval' of expanding all defmacros in scheme expression E. - Function: defmacro:load FILENAME FILENAME should be a string. If filename names an existing file, the `defmacro:load' procedure reads Scheme source code expressions and definitions from the file and evaluates them sequentially. These source code expressions and definitions may contain defmacro definitions. The `macro:load' procedure does not affect the values returned by `current-input-port' and `current-output-port'. - Function: defmacro? SYM Returns `#t' if SYM has been defined by `defmacro', `#f' otherwise. - Function: macroexpand-1 FORM - Function: macroexpand FORM If FORM is a macro call, `macroexpand-1' will expand the macro call once and return it. A FORM is considered to be a macro call only if it is a cons whose `car' is a symbol for which a `defmacr' has been defined. `macroexpand' is similar to `macroexpand-1', but repeatedly expands FORM until it is no longer a macro call. - Macro: defmacro NAME LAMBDA-LIST FORM ... When encountered by `defmacro:eval', `defmacro:macroexpand*', or `defmacro:load' defines a new macro which will henceforth be expanded when encountered by `defmacro:eval', `defmacro:macroexpand*', or `defmacro:load'. Defmacroexpand -------------- `(require 'defmacroexpand)' - Function: defmacro:expand* E Returns the result of expanding all defmacros in scheme expression E. File: slib.info, Node: R4RS Macros, Next: Macro by Example, Prev: Defmacro, Up: Scheme Syntax Extension Packages R4RS Macros =========== `(require 'macro)' is the appropriate call if you want R4RS high-level macros but don't care about the low level implementation. If an SLIB R4RS macro implementation is already loaded it will be used. Otherwise, one of the R4RS macros implemetations is loaded. The SLIB R4RS macro implementations support the following uniform interface: - Function: macro:expand SEXPRESSION Takes an R4RS expression, macro-expands it, and returns the result of the macro expansion. - Function: macro:eval SEXPRESSION Takes an R4RS expression, macro-expands it, evals the result of the macro expansion, and returns the result of the evaluation. - Procedure: macro:load FILENAME FILENAME should be a string. If filename names an existing file, the `macro:load' procedure reads Scheme source code expressions and definitions from the file and evaluates them sequentially. These source code expressions and definitions may contain macro definitions. The `macro:load' procedure does not affect the values returned by `current-input-port' and `current-output-port'. File: slib.info, Node: Macro by Example, Next: Macros That Work, Prev: R4RS Macros, Up: Scheme Syntax Extension Packages Macro by Example ================ `(require 'macro-by-example)' A vanilla implementation of `Macro by Example' (Eugene Kohlbecker, R4RS) by Dorai Sitaram, (dorai@cs.rice.edu) using `defmacro'. * generating hygienic global `define-syntax' Macro-by-Example macros *cheaply*. * can define macros which use `...'. * needn't worry about a lexical variable in a macro definition clashing with a variable from the macro use context * don't suffer the overhead of redefining the repl if `defmacro' natively supported (most implementations) Caveat ------ These macros are not referentially transparent (*note Macros: (r4rs)Macros.). Lexically scoped macros (i.e., `let-syntax' and `letrec-syntax') are not supported. In any case, the problem of referential transparency gains poignancy only when `let-syntax' and `letrec-syntax' are used. So you will not be courting large-scale disaster unless you're using system-function names as local variables with unintuitive bindings that the macro can't use. However, if you must have the full `r4rs' macro functionality, look to the more featureful (but also more expensive) versions of syntax-rules available in slib *Note Macros That Work::, *Note Syntactic Closures::, and *Note Syntax-Case Macros::. - Macro: define-syntax KEYWORD TRANSFORMER-SPEC The KEYWORD is an identifier, and the TRANSFORMER-SPEC should be an instance of `syntax-rules'. The top-level syntactic environment is extended by binding the KEYWORD to the specified transformer. (define-syntax let* (syntax-rules () ((let* () body1 body2 ...) (let () body1 body2 ...)) ((let* ((name1 val1) (name2 val2) ...) body1 body2 ...) (let ((name1 val1)) (let* (( name2 val2) ...) body1 body2 ...))))) - Macro: syntax-rules LITERALS SYNTAX-RULE ... LITERALS is a list of identifiers, and each SYNTAX-RULE should be of the form `(PATTERN TEMPLATE)' where the PATTERN and TEMPLATE are as in the grammar above. An instance of `syntax-rules' produces a new macro transformer by specifying a sequence of hygienic rewrite rules. A use of a macro whose keyword is associated with a transformer specified by `syntax-rules' is matched against the patterns contained in the SYNTAX-RULEs, beginning with the leftmost SYNTAX-RULE. When a match is found, the macro use is trancribed hygienically according to the template. Each pattern begins with the keyword for the macro. This keyword is not involved in the matching and is not considered a pattern variable or literal identifier. File: slib.info, Node: Macros That Work, Next: Syntactic Closures, Prev: Macro by Example, Up: Scheme Syntax Extension Packages Macros That Work ================ `(require 'macros-that-work)' `Macros That Work' differs from the other R4RS macro implementations in that it does not expand derived expression types to primitive expression types. - Function: macro:expand EXPRESSION - Function: macwork:expand EXPRESSION Takes an R4RS expression, macro-expands it, and returns the result of the macro expansion. - Function: macro:eval EXPRESSION - Function: macwork:eval EXPRESSION `macro:eval' returns the value of EXPRESSION in the current top level environment. EXPRESSION can contain macro definitions. Side effects of EXPRESSION will affect the top level environment. - Procedure: macro:load FILENAME - Procedure: macwork:load FILENAME FILENAME should be a string. If filename names an existing file, the `macro:load' procedure reads Scheme source code expressions and definitions from the file and evaluates them sequentially. These source code expressions and definitions may contain macro definitions. The `macro:load' procedure does not affect the values returned by `current-input-port' and `current-output-port'. References: The `Revised^4 Report on the Algorithmic Language Scheme' Clinger and Rees [editors]. To appear in LISP Pointers. Also available as a technical report from the University of Oregon, MIT AI Lab, and Cornell. Macros That Work. Clinger and Rees. POPL '91. The supported syntax differs from the R4RS in that vectors are allowed as patterns and as templates and are not allowed as pattern or template data. transformer spec ==> (syntax-rules literals rules) rules ==> () | (rule . rules) rule ==> (pattern template) pattern ==> pattern_var ; a symbol not in literals | symbol ; a symbol in literals | () | (pattern . pattern) | (ellipsis_pattern) | #(pattern*) ; extends R4RS | #(pattern* ellipsis_pattern) ; extends R4RS | pattern_datum template ==> pattern_var | symbol | () | (template2 . template2) | #(template*) ; extends R4RS | pattern_datum template2 ==> template | ellipsis_template pattern_datum ==> string ; no vector | character | boolean | number ellipsis_pattern ==> pattern ... ellipsis_template ==> template ... pattern_var ==> symbol ; not in literals literals ==> () | (symbol . literals) Definitions ----------- Scope of an ellipsis Within a pattern or template, the scope of an ellipsis (`...') is the pattern or template that appears to its left. Rank of a pattern variable The rank of a pattern variable is the number of ellipses within whose scope it appears in the pattern. Rank of a subtemplate The rank of a subtemplate is the number of ellipses within whose scope it appears in the template. Template rank of an occurrence of a pattern variable The template rank of an occurrence of a pattern variable within a template is the rank of that occurrence, viewed as a subtemplate. Variables bound by a pattern The variables bound by a pattern are the pattern variables that appear within it. Referenced variables of a subtemplate The referenced variables of a subtemplate are the pattern variables that appear within it. Variables opened by an ellipsis template The variables opened by an ellipsis template are the referenced pattern variables whose rank is greater than the rank of the ellipsis template. Restrictions ------------ No pattern variable appears more than once within a pattern. For every occurrence of a pattern variable within a template, the template rank of the occurrence must be greater than or equal to the pattern variable's rank. Every ellipsis template must open at least one variable. For every ellipsis template, the variables opened by an ellipsis template must all be bound to sequences of the same length. The compiled form of a RULE is rule ==> (pattern template inserted) pattern ==> pattern_var | symbol | () | (pattern . pattern) | ellipsis_pattern | #(pattern) | pattern_datum template ==> pattern_var | symbol | () | (template2 . template2) | #(pattern) | pattern_datum template2 ==> template | ellipsis_template pattern_datum ==> string | character | boolean | number pattern_var ==> #(V symbol rank) ellipsis_pattern ==> #(E pattern pattern_vars) ellipsis_template ==> #(E template pattern_vars) inserted ==> () | (symbol . inserted) pattern_vars ==> () | (pattern_var . pattern_vars) rank ==> exact non-negative integer where V and E are unforgeable values. The pattern variables associated with an ellipsis pattern are the variables bound by the pattern, and the pattern variables associated with an ellipsis template are the variables opened by the ellipsis template. If the template contains a big chunk that contains no pattern variables or inserted identifiers, then the big chunk will be copied unnecessarily. That shouldn't matter very often. File: slib.info, Node: Syntactic Closures, Next: Syntax-Case Macros, Prev: Macros That Work, Up: Scheme Syntax Extension Packages Syntactic Closures ================== `(require 'syntactic-closures)' - Function: macro:expand EXPRESSION - Function: synclo:expand EXPRESSION Returns scheme code with the macros and derived expression types of EXPRESSION expanded to primitive expression types. - Function: macro:eval EXPRESSION - Function: synclo:eval EXPRESSION `macro:eval' returns the value of EXPRESSION in the current top level environment. EXPRESSION can contain macro definitions. Side effects of EXPRESSION will affect the top level environment. - Procedure: macro:load FILENAME - Procedure: synclo:load FILENAME FILENAME should be a string. If filename names an existing file, the `macro:load' procedure reads Scheme source code expressions and definitions from the file and evaluates them sequentially. These source code expressions and definitions may contain macro definitions. The `macro:load' procedure does not affect the values returned by `current-input-port' and `current-output-port'. Syntactic Closure Macro Facility -------------------------------- A Syntactic Closures Macro Facility by Chris Hanson 9 November 1991 This document describes "syntactic closures", a low-level macro facility for the Scheme programming language. The facility is an alternative to the low-level macro facility described in the `Revised^4 Report on Scheme.' This document is an addendum to that report. The syntactic closures facility extends the BNF rule for TRANSFORMER SPEC to allow a new keyword that introduces a low-level macro transformer: TRANSFORMER SPEC := (transformer EXPRESSION) Additionally, the following procedures are added: make-syntactic-closure capture-syntactic-environment identifier? identifier=? The description of the facility is divided into three parts. The first part defines basic terminology. The second part describes how macro transformers are defined. The third part describes the use of "identifiers", which extend the syntactic closure mechanism to be compatible with `syntax-rules'. Terminology ........... This section defines the concepts and data types used by the syntactic closures facility. * "Forms" are the syntactic entities out of which programs are recursively constructed. A form is any expression, any definition, any syntactic keyword, or any syntactic closure. The variable name that appears in a `set!' special form is also a form. Examples of forms: 17 #t car (+ x 4) (lambda (x) x) (define pi 3.14159) if define * An "alias" is an alternate name for a given symbol. It can appear anywhere in a form that the symbol could be used, and when quoted it is replaced by the symbol; however, it does not satisfy the predicate `symbol?'. Macro transformers rarely distinguish symbols from aliases, referring to both as identifiers. * A "syntactic" environment maps identifiers to their meanings. More precisely, it determines whether an identifier is a syntactic keyword or a variable. If it is a keyword, the meaning is an interpretation for the form in which that keyword appears. If it is a variable, the meaning identifies which binding of that variable is referenced. In short, syntactic environments contain all of the contextual information necessary for interpreting the meaning of a particular form. * A "syntactic closure" consists of a form, a syntactic environment, and a list of identifiers. All identifiers in the form take their meaning from the syntactic environment, except those in the given list. The identifiers in the list are to have their meanings determined later. A syntactic closure may be used in any context in which its form could have been used. Since a syntactic closure is also a form, it may not be used in contexts where a form would be illegal. For example, a form may not appear as a clause in the cond special form. A syntactic closure appearing in a quoted structure is replaced by its form. Transformer Definition ...................... This section describes the `transformer' special form and the procedures `make-syntactic-closure' and `capture-syntactic-environment'. - Syntax: transformer EXPRESSION Syntax: It is an error if this syntax occurs except as a TRANSFORMER SPEC. Semantics: The EXPRESSION is evaluated in the standard transformer environment to yield a macro transformer as described below. This macro transformer is bound to a macro keyword by the special form in which the `transformer' expression appears (for example, `let-syntax'). A "macro transformer" is a procedure that takes two arguments, a form and a syntactic environment, and returns a new form. The first argument, the "input form", is the form in which the macro keyword occurred. The second argument, the "usage environment", is the syntactic environment in which the input form occurred. The result of the transformer, the "output form", is automatically closed in the "transformer environment", which is the syntactic environment in which the `transformer' expression occurred. For example, here is a definition of a push macro using `syntax-rules': (define-syntax push (syntax-rules () ((push item list) (set! list (cons item list))))) Here is an equivalent definition using `transformer': (define-syntax push (transformer (lambda (exp env) (let ((item (make-syntactic-closure env '() (cadr exp))) (list (make-syntactic-closure env '() (caddr exp)))) `(set! ,list (cons ,item ,list)))))) In this example, the identifiers `set!' and `cons' are closed in the transformer environment, and thus will not be affected by the meanings of those identifiers in the usage environment `env'. Some macros may be non-hygienic by design. For example, the following defines a loop macro that implicitly binds `exit' to an escape procedure. The binding of `exit' is intended to capture free references to `exit' in the body of the loop, so `exit' must be left free when the body is closed: (define-syntax loop (transformer (lambda (exp env) (let ((body (cdr exp))) `(call-with-current-continuation (lambda (exit) (let f () ,@(map (lambda (exp) (make-syntactic-closure env '(exit) exp)) body) (f)))))))) To assign meanings to the identifiers in a form, use `make-syntactic-closure' to close the form in a syntactic environment. - Function: make-syntactic-closure ENVIRONMENT FREE-NAMES FORM ENVIRONMENT must be a syntactic environment, FREE-NAMES must be a list of identifiers, and FORM must be a form. `make-syntactic-closure' constructs and returns a syntactic closure of FORM in ENVIRONMENT, which can be used anywhere that FORM could have been used. All the identifiers used in FORM, except those explicitly excepted by FREE-NAMES, obtain their meanings from ENVIRONMENT. Here is an example where FREE-NAMES is something other than the empty list. It is instructive to compare the use of FREE-NAMES in this example with its use in the `loop' example above: the examples are similar except for the source of the identifier being left free. (define-syntax let1 (transformer (lambda (exp env) (let ((id (cadr exp)) (init (caddr exp)) (exp (cadddr exp))) `((lambda (,id) ,(make-syntactic-closure env (list id) exp)) ,(make-syntactic-closure env '() init)))))) `let1' is a simplified version of `let' that only binds a single identifier, and whose body consists of a single expression. When the body expression is syntactically closed in its original syntactic environment, the identifier that is to be bound by `let1' must be left free, so that it can be properly captured by the `lambda' in the output form. To obtain a syntactic environment other than the usage environment, use `capture-syntactic-environment'. - Function: capture-syntactic-environment PROCEDURE `capture-syntactic-environment' returns a form that will, when transformed, call PROCEDURE on the current syntactic environment. PROCEDURE should compute and return a new form to be transformed, in that same syntactic environment, in place of the form. An example will make this clear. Suppose we wanted to define a simple `loop-until' keyword equivalent to (define-syntax loop-until (syntax-rules () ((loop-until id init test return step) (letrec ((loop (lambda (id) (if test return (loop step))))) (loop init))))) The following attempt at defining `loop-until' has a subtle bug: (define-syntax loop-until (transformer (lambda (exp env) (let ((id (cadr exp)) (init (caddr exp)) (test (cadddr exp)) (return (cadddr (cdr exp))) (step (cadddr (cddr exp))) (close (lambda (exp free) (make-syntactic-closure env free exp)))) `(letrec ((loop (lambda (,id) (if ,(close test (list id)) ,(close return (list id)) (loop ,(close step (list id))))))) (loop ,(close init '()))))))) This definition appears to take all of the proper precautions to prevent unintended captures. It carefully closes the subexpressions in their original syntactic environment and it leaves the `id' identifier free in the `test', `return', and `step' expressions, so that it will be captured by the binding introduced by the `lambda' expression. Unfortunately it uses the identifiers `if' and `loop' within that `lambda' expression, so if the user of `loop-until' just happens to use, say, `if' for the identifier, it will be inadvertently captured. The syntactic environment that `if' and `loop' want to be exposed to is the one just outside the `lambda' expression: before the user's identifier is added to the syntactic environment, but after the identifier loop has been added. `capture-syntactic-environment' captures exactly that environment as follows: (define-syntax loop-until (transformer (lambda (exp env) (let ((id (cadr exp)) (init (caddr exp)) (test (cadddr exp)) (return (cadddr (cdr exp))) (step (cadddr (cddr exp))) (close (lambda (exp free) (make-syntactic-closure env free exp)))) `(letrec ((loop ,(capture-syntactic-environment (lambda (env) `(lambda (,id) (,(make-syntactic-closure env '() `if) ,(close test (list id)) ,(close return (list id)) (,(make-syntactic-closure env '() `loop) ,(close step (list id))))))))) (loop ,(close init '()))))))) In this case, having captured the desired syntactic environment, it is convenient to construct syntactic closures of the identifiers `if' and the `loop' and use them in the body of the `lambda'. A common use of `capture-syntactic-environment' is to get the transformer environment of a macro transformer: (transformer (lambda (exp env) (capture-syntactic-environment (lambda (transformer-env) ...)))) Identifiers ........... This section describes the procedures that create and manipulate identifiers. Previous syntactic closure proposals did not have an identifier data type - they just used symbols. The identifier data type extends the syntactic closures facility to be compatible with the high-level `syntax-rules' facility. As discussed earlier, an identifier is either a symbol or an "alias". An alias is implemented as a syntactic closure whose "form" is an identifier: (make-syntactic-closure env '() 'a) => an "alias" Aliases are implemented as syntactic closures because they behave just like syntactic closures most of the time. The difference is that an alias may be bound to a new value (for example by `lambda' or `let-syntax'); other syntactic closures may not be used this way. If an alias is bound, then within the scope of that binding it is looked up in the syntactic environment just like any other identifier. Aliases are used in the implementation of the high-level facility `syntax-rules'. A macro transformer created by `syntax-rules' uses a template to generate its output form, substituting subforms of the input form into the template. In a syntactic closures implementation, all of the symbols in the template are replaced by aliases closed in the transformer environment, while the output form itself is closed in the usage environment. This guarantees that the macro transformation is hygienic, without requiring the transformer to know the syntactic roles of the substituted input subforms. - Function: identifier? OBJECT Returns `#t' if OBJECT is an identifier, otherwise returns `#f'. Examples: (identifier? 'a) => #t (identifier? (make-syntactic-closure env '() 'a)) => #t (identifier? "a") => #f (identifier? #\a) => #f (identifier? 97) => #f (identifier? #f) => #f (identifier? '(a)) => #f (identifier? '#(a)) => #f The predicate `eq?' is used to determine if two identifers are "the same". Thus `eq?' can be used to compare identifiers exactly as it would be used to compare symbols. Often, though, it is useful to know whether two identifiers "mean the same thing". For example, the `cond' macro uses the symbol `else' to identify the final clause in the conditional. A macro transformer for `cond' cannot just look for the symbol `else', because the `cond' form might be the output of another macro transformer that replaced the symbol `else' with an alias. Instead the transformer must look for an identifier that "means the same thing" in the usage environment as the symbol `else' means in the transformer environment. - Function: identifier=? ENVIRONMENT1 IDENTIFIER1 ENVIRONMENT2 IDENTIFIER2 ENVIRONMENT1 and ENVIRONMENT2 must be syntactic environments, and IDENTIFIER1 and IDENTIFIER2 must be identifiers. `identifier=?' returns `#t' if the meaning of IDENTIFIER1 in ENVIRONMENT1 is the same as that of IDENTIFIER2 in ENVIRONMENT2, otherwise it returns `#f'. Examples: (let-syntax ((foo (transformer (lambda (form env) (capture-syntactic-environment (lambda (transformer-env) (identifier=? transformer-env 'x env 'x))))))) (list (foo) (let ((x 3)) (foo)))) => (#t #f) (let-syntax ((bar foo)) (let-syntax ((foo (transformer (lambda (form env) (capture-syntactic-environment (lambda (transformer-env) (identifier=? transformer-env 'foo env (cadr form)))))))) (list (foo foo) (foobar)))) => (#f #t) Acknowledgements ................ The syntactic closures facility was invented by Alan Bawden and Jonathan Rees. The use of aliases to implement `syntax-rules' was invented by Alan Bawden (who prefers to call them "synthetic names"). Much of this proposal is derived from an earlier proposal by Alan Bawden. File: slib.info, Node: Syntax-Case Macros, Next: Fluid-Let, Prev: Syntactic Closures, Up: Scheme Syntax Extension Packages Syntax-Case Macros ================== `(require 'syntax-case)' - Function: macro:expand EXPRESSION - Function: syncase:expand EXPRESSION Returns scheme code with the macros and derived expression types of EXPRESSION expanded to primitive expression types. - Function: macro:eval EXPRESSION - Function: syncase:eval EXPRESSION `macro:eval' returns the value of EXPRESSION in the current top level environment. EXPRESSION can contain macro definitions. Side effects of EXPRESSION will affect the top level environment. - Procedure: macro:load FILENAME - Procedure: syncase:load FILENAME FILENAME should be a string. If filename names an existing file, the `macro:load' procedure reads Scheme source code expressions and definitions from the file and evaluates them sequentially. These source code expressions and definitions may contain macro definitions. The `macro:load' procedure does not affect the values returned by `current-input-port' and `current-output-port'. This is version 2.1 of `syntax-case', the low-level macro facility proposed and implemented by Robert Hieb and R. Kent Dybvig. This version is further adapted by Harald Hanche-Olsen <hanche@imf.unit.no> to make it compatible with, and easily usable with, SLIB. Mainly, these adaptations consisted of: * Removing white space from `expand.pp' to save space in the distribution. This file is not meant for human readers anyway... * Removed a couple of Chez scheme dependencies. * Renamed global variables used to minimize the possibility of name conflicts. * Adding an SLIB-specific initialization file. * Removing a couple extra files, most notably the documentation (but see below). If you wish, you can see exactly what changes were done by reading the shell script in the file `syncase.sh'. The two PostScript files were omitted in order to not burden the SLIB distribution with them. If you do intend to use `syntax-case', however, you should get these files and print them out on a PostScript printer. They are available with the original `syntax-case' distribution by anonymous FTP in `cs.indiana.edu:/pub/scheme/syntax-case'. In order to use syntax-case from an interactive top level, execute: (require 'syntax-case) (require 'repl) (repl:top-level macro:eval) See the section Repl (*Note Repl::) for more information. To check operation of syntax-case get `cs.indiana.edu:/pub/scheme/syntax-case', and type (require 'syntax-case) (syncase:sanity-check) Beware that `syntax-case' takes a long time to load - about 20s on a SPARCstation SLC (with SCM) and about 90s on a Macintosh SE/30 (with Gambit). Notes ----- All R4RS syntactic forms are defined, including `delay'. Along with `delay' are simple definitions for `make-promise' (into which `delay' expressions expand) and `force'. `syntax-rules' and `with-syntax' (described in `TR356') are defined. `syntax-case' is actually defined as a macro that expands into calls to the procedure `syntax-dispatch' and the core form `syntax-lambda'; do not redefine these names. Several other top-level bindings not documented in TR356 are created: * the "hooks" in `hooks.ss' * the `build-' procedures in `output.ss' * `expand-syntax' (the expander) The syntax of define has been extended to allow `(define ID)', which assigns ID to some unspecified value. We have attempted to maintain R4RS compatibility where possible. The incompatibilities should be confined to `hooks.ss'. Please let us know if there is some incompatibility that is not flagged as such. Send bug reports, comments, suggestions, and questions to Kent Dybvig (dyb@iuvax.cs.indiana.edu). Note from maintainer -------------------- Included with the `syntax-case' files was `structure.scm' which defines a macro `define-structure'. There is no documentation for this macro and it is not used by any code in SLIB. File: slib.info, Node: Fluid-Let, Next: Yasos, Prev: Syntax-Case Macros, Up: Scheme Syntax Extension Packages Fluid-Let ========= `(require 'fluid-let)' - Syntax: fluid-let `(BINDINGS ...)' FORMS... (fluid-let ((VARIABLE INIT) ...) EXPRESSION EXPRESSION ...) The INITs are evaluated in the current environment (in some unspecified order), the current values of the VARIABLEs are saved, the results are assigned to the VARIABLEs, the EXPRESSIONs are evaluated sequentially in the current environment, the VARIABLEs are restored to their original values, and the value of the last EXPRESSION is returned. The syntax of this special form is similar to that of `let', but `fluid-let' temporarily rebinds existing VARIABLEs. Unlike `let', `fluid-let' creates no new bindings; instead it *assigns* the values of each INIT to the binding (determined by the rules of lexical scoping) of its corresponding VARIABLE. File: slib.info, Node: Yasos, Prev: Fluid-Let, Up: Scheme Syntax Extension Packages Yasos ===== `(require 'oop)' or `(require 'yasos)' `Yet Another Scheme Object System' is a simple object system for Scheme based on the paper by Norman Adams and Jonathan Rees: `Object Oriented Programming in Scheme', Proceedings of the 1988 ACM Conference on LISP and Functional Programming, July 1988 [ACM #552880]. Another reference is: Ken Dickey. Scheming with Objects `AI Expert' Volume 7, Number 10 (October 1992), pp. 24-33. * Menu: * Yasos terms:: Definitions and disclaimer. * Yasos interface:: The Yasos macros and procedures. * Setters:: Dylan-like setters in Yasos. * Yasos examples:: Usage of Yasos and setters. File: slib.info, Node: Yasos terms, Next: Yasos interface, Prev: Yasos, Up: Yasos Terms ----- "Object" Any Scheme data object. "Instance" An instance of the OO system; an "object". "Operation" A METHOD. *Notes:* The object system supports multiple inheritance. An instance can inherit from 0 or more ancestors. In the case of multiple inherited operations with the same identity, the operation used is that from the first ancestor which contains it (in the ancestor `let'). An operation may be applied to any Scheme data object--not just instances. As code which creates instances is just code, there are no "classes" and no meta-ANYTHING. Method dispatch is by a procedure call a la CLOS rather than by `send' syntax a la Smalltalk. *Disclaimer:* There are a number of optimizations which can be made. This implementation is expository (although performance should be quite reasonable). See the L&FP paper for some suggestions. File: slib.info, Node: Yasos interface, Next: Setters, Prev: Yasos terms, Up: Yasos Interface --------- - Syntax: define-operation `('OPNAME SELF ARG ...`)' DEFAULT-BODY Defines a default behavior for data objects which don't handle the operation OPNAME. The default behavior (for an empty DEFAULT-BODY) is to generate an error. - Syntax: define-predicate OPNAME? Defines a predicate OPNAME?, usually used for determining the "type" of an object, such that `(OPNAME? OBJECT)' returns `#t' if OBJECT has an operation OPNAME? and `#f' otherwise. - Syntax: object `((NAME SELF ARG ...) BODY)' ... Returns an object (an instance of the object system) with operations. Invoking `(NAME OBJECT ARG ...' executes the BODY of the OBJECT with SELF bound to OBJECT and with argument(s) ARG.... - Syntax: object-with-ancestors `(('ANCESTOR1 INIT1`)' ...`)' OPERATION ... A `let'-like form of `object' for multiple inheritance. It returns an object inheriting the behaviour of ANCESTOR1 etc. An operation will be invoked in an ancestor if the object itself does not provide such a method. In the case of multiple inherited operations with the same identity, the operation used is the one found in the first ancestor in the ancestor list. - Syntax: operate-as COMPONENT OPERATION SELF ARG ... Used in an operation definition (of SELF) to invoke the OPERATION in an ancestor COMPONENT but maintain the object's identity. Also known as "send-to-super". - Procedure: print OBJ PORT A default `print' operation is provided which is just `(format PORT OBJ)' (*Note Format::) for non-instances and prints OBJ preceded by `#<INSTANCE>' for instances. - Function: size OBJ The default method returns the number of elements in OBJ if it is a vector, string or list, `2' for a pair, `1' for a character and by default id an error otherwise. Objects such as collections (*Note Collections::) may override the default in an obvious way. File: slib.info, Node: Setters, Next: Yasos examples, Prev: Yasos interface, Up: Yasos Setters ------- "Setters" implement "generalized locations" for objects associated with some sort of mutable state. A "getter" operation retrieves a value from a generalized location and the corresponding setter operation stores a value into the location. Only the getter is named - the setter is specified by a procedure call as below. (Dylan uses special syntax.) Typically, but not necessarily, getters are access operations to extract values from Yasos objects (*Note Yasos::). Several setters are predefined, corresponding to getters `car', `cdr', `string-ref' and `vector-ref' e.g., `(setter car)' is equivalent to `set-car!'. This implementation of setters is similar to that in Dylan(TM) (`Dylan: An object-oriented dynamic language', Apple Computer Eastern Research and Technology). Common LISP provides similar facilities through `setf'. - Function: setter GETTER Returns the setter for the procedure GETTER. E.g., since `string-ref' is the getter corresponding to a setter which is actually `string-set!': (define foo "foo") ((setter string-ref) foo 0 #\F) ; set element 0 of foo foo => "Foo" - Syntax: set PLACE NEW-VALUE If PLACE is a variable name, `set' is equivalent to `set!'. Otherwise, PLACE must have the form of a procedure call, where the procedure name refers to a getter and the call indicates an accessible generalized location, i.e., the call would return a value. The return value of `set' is usually unspecified unless used with a setter whose definition guarantees to return a useful value. (set (string-ref foo 2) #\O) ; generalized location with getter foo => "FoO" (set foo "foo") ; like set! foo => "foo" - Procedure: add-setter GETTER SETTER Add procedures GETTER and SETTER to the (inaccessible) list of valid setter/getter pairs. SETTER implements the store operation corresponding to the GETTER access operation for the relevant state. The return value is unspecified. - Procedure: remove-setter-for GETTER Removes the setter corresponding to the specified GETTER from the list of valid setters. The return value is unspecified. - Syntax: define-access-operation GETTER-NAME Shorthand for a Yasos `define-operation' defining an operation GETTER-NAME that objects may support to return the value of some mutable state. The default operation is to signal an error. The return value is unspecified. File: slib.info, Node: Yasos examples, Prev: Setters, Up: Yasos Examples -------- ;;; These definitions for PRINT and SIZE are | ;;; already supplied by | (require 'yasos) (define-operation (print obj port) (format port (if (instance? obj) "#<instance>" "~s") obj)) (define-operation (size obj) (cond ((vector? obj) (vector-length obj)) ((list? obj) (length obj)) ((pair? obj) 2) ((string? obj) (string-length obj)) ((char? obj) 1) (else (error "Operation not supported: size" obj)))) (define-predicate cell?) (define-operation (fetch obj)) (define-operation (store! obj newValue)) (define (make-cell value) (object ((cell? self) #t) ((fetch self) value) ((store! self newValue) (set! value newValue) newValue) ((size self) 1) ((print self port) (format port "#<Cell: ~s>" (fetch self))))) (define-operation (discard obj value) (format #t "Discarding ~s~%" value)) (define (make-filtered-cell value filter) (object-with-ancestors | ((cell (make-cell value))) | ((store! self newValue) (if (filter newValue) (store! cell newValue) (discard self newValue))))) (define-predicate array?) (define-operation (array-ref array index)) (define-operation (array-set! array index value)) (define (make-array num-slots) (let ((anArray (make-vector num-slots))) (object ((array? self) #t) ((size self) num-slots) ((array-ref self index) | (vector-ref anArray index)) | ((array-set! self index newValue) | (vector-set! anArray index newValue)) | ((print self port) | (format port "#<Array ~s>" (size self)))))) | (define-operation (position obj)) (define-operation (discarded-value obj)) (define (make-cell-with-history value filter size) (let ((pos 0) (most-recent-discard #f)) (object-with-ancestors ((cell (make-filtered-call value filter)) (sequence (make-array size))) ((array? self) #f) ((position self) pos) ((store! self newValue) (operate-as cell store! self newValue) (array-set! self pos newValue) (set! pos (+ pos 1))) ((discard self value) (set! most-recent-discard value)) ((discarded-value self) most-recent-discard) ((print self port) (format port "#<Cell-with-history ~s>" | (fetch self)))))) | (define-access-operation fetch) (add-setter fetch store!) (define foo (make-cell 1)) (print foo #f) => "#<Cell: 1>" (set (fetch foo) 2) => (print foo #f) => "#<Cell: 2>" (fetch foo) => 2 File: slib.info, Node: Textual Conversion Packages, Next: Mathematical Packages, Prev: Scheme Syntax Extension Packages, Up: Top Textual Conversion Packages *************************** * Menu: * Precedence Parsing:: * Format:: Common-Lisp Format * Standard Formatted I/O:: Posix printf and scanf * Programs and Arguments:: * HTML HTTP and CGI:: Generate pages and serve WWW sites * Printing Scheme:: Nicely * Time and Date:: * Vector Graphics:: * Schmooz:: Documentation markup for Scheme programs File: slib.info, Node: Precedence Parsing, Next: Format, Prev: Textual Conversion Packages, Up: Textual Conversion Packages Precedence Parsing ================== `(require 'precedence-parse)' or `(require 'parse)' This package implements: * a Pratt style precedence parser; * a "tokenizer" which congeals tokens according to assigned classes of constituent characters; * procedures giving direct control of parser rulesets; * procedures for higher level specification of rulesets. * Menu: * Precedence Parsing Overview:: * Ruleset Definition and Use:: * Token definition:: * Nud and Led Definition:: * Grammar Rule Definition:: File: slib.info, Node: Precedence Parsing Overview, Next: Ruleset Definition and Use, Prev: Precedence Parsing, Up: Precedence Parsing Precedence Parsing Overview --------------------------- This package offers improvements over previous parsers. * Common computer language constructs are concisely specified. * Grammars can be changed dynamically. Operators can be assigned different meanings within a lexical context. * Rulesets don't need compilation. Grammars can be changed incrementally. * Operator precedence is specified by integers. * All possibilities of bad input are handled (1) and return as much structure as was parsed when the error occured; The symbol `?' is substituted for missing input. Here are the higher-level syntax types and an example of each. Precedence considerations are omitted for clarity. *Note Grammar Rule Definition:: for full details. - Grammar: nofix bye exit bye calls the function `exit' with no arguments. - Grammar: prefix - negate - 42 Calls the function `negate' with the argument `42'. - Grammar: infix - difference x - y Calls the function `difference' with arguments `x' and `y'. - Grammar: nary + sum x + y + z Calls the function `sum' with arguments `x', `y', and `y'. - Grammar: postfix ! factorial 5 ! Calls the function `factorial' with the argument `5'. - Grammar: prestfix set set! set foo bar Calls the function `set!' with the arguments `foo' and `bar'. - Grammar: commentfix /* */ /* almost any text here */ Ignores the comment delimited by `/*' and `*/'. - Grammar: matchfix { list } {0, 1, 2} Calls the function `list' with the arguments `0', `1', and `2'. - Grammar: inmatchfix ( funcall ) f(x, y) Calls the function `funcall' with the arguments `f', `x', and `y'. - Grammar: delim ; set foo bar; delimits the extent of the restfix operator `set'. ---------- Footnotes ---------- (1) How do I know this? I parsed 250kbyte of random input (an e-mail file) with a non-trivial grammar utilizing all constructs. File: slib.info, Node: Ruleset Definition and Use, Next: Token definition, Prev: Precedence Parsing Overview, Up: Precedence Parsing Ruleset Definition and Use -------------------------- - Variable: *syn-defs* A grammar is built by one or more calls to `prec:define-grammar'. The rules are appended to *SYN-DEFS*. The value of *SYN-DEFS* is the grammar suitable for passing as an argument to `prec:parse'. - Constant: *syn-ignore-whitespace* Is a nearly empty grammar with whitespace characters set to group 0, which means they will not be made into tokens. Most rulesets will want to start with `*syn-ignore-whitespace*' In order to start defining a grammar, either (set! *syn-defs* '()) (set! *syn-defs* *syn-ignore-whitespace*) - Function: prec:define-grammar RULE1 ... Appends RULE1 ... to *SYN-DEFS*. `prec:define-grammar' is used to define both the character classes and rules for tokens. Once your grammar is defined, save the value of `*syn-defs*' in a variable (for use when calling `prec:parse'). (define my-ruleset *syn-defs*) - Function: prec:parse RULESET DELIM - Function: prec:parse RULESET DELIM PORT The RULESET argument must be a list of rules as constructed by `prec:define-grammar' and extracted from *SYN-DEFS*. The token DELIM may be a character, symbol, or string. A character DELIM argument will match only a character token; i.e. a character for which no token-group is assigned. A symbols or string will match only a token string; i.e. a token resulting from a token group. `prec:parse' reads a RULESET grammar expression delimited by DELIM from the given input PORT. `prec:parse' returns the next object parsable from the given input PORT, updating PORT to point to the first character past the end of the external representation of the object. If an end of file is encountered in the input before any characters are found that can begin an object, then an end of file object is returned. If a delimiter (such as DELIM) is found before any characters are found that can begin an object, then `#f' is returned. The PORT argument may be omitted, in which case it defaults to the value returned by `current-input-port'. It is an error to parse from a closed port. File: slib.info, Node: Token definition, Next: Nud and Led Definition, Prev: Ruleset Definition and Use, Up: Precedence Parsing Token definition ---------------- - Function: tok:char-group GROUP CHARS CHARS-PROC The argument CHARS may be a single character, a list of characters, or a string. Each character in CHARS is treated as though `tok:char-group' was called with that character alone. The argument CHARS-PROC must be a procedure of one argument, a list of characters. After `tokenize' has finished accumulating the characters for a token, it calls CHARS-PROC with the list of characters. The value returned is the token which `tokenize' returns. The argument GROUP may be an exact integer or a procedure of one character argument. The following discussion concerns the treatment which the tokenizing routine, `tokenize', will accord to characters on the basis of their groups. When GROUP is a non-zero integer, characters whose group number is equal to or exactly one less than GROUP will continue to accumulate. Any other character causes the accumulation to stop (until a new token is to be read). The GROUP of zero is special. These characters are ignored when parsed pending a token, and stop the accumulation of token characters when the accumulation has already begun. Whitespace characters are usually put in group 0. If GROUP is a procedure, then, when triggerd by the occurence of an initial (no accumulation) CHARS character, this procedure will be repeatedly called with each successive character from the input stream until the GROUP procedure returns a non-false value. The following convenient constants are provided for use with `tok:char-group'. - Constant: tok:decimal-digits Is the string `"0123456789"'. - Constant: tok:upper-case Is the string consisting of all upper-case letters ("ABCDEFGHIJKLMNOPQRSTUVWXYZ"). - Constant: tok:lower-case Is the string consisting of all lower-case letters ("abcdefghijklmnopqrstuvwxyz"). - Constant: tok:whitespaces Is the string consisting of all characters between 0 and 255 for which `char-whitespace?' returns true. File: slib.info, Node: Nud and Led Definition, Next: Grammar Rule Definition, Prev: Token definition, Up: Precedence Parsing Nud and Led Definition ---------------------- This section describes advanced features. You can skip this section on first reading. The "Null Denotation" (or "nud") of a token is the procedure and arguments applying for that token when "Left", an unclaimed parsed expression is not extant. The "Left Denotation" (or "led") of a token is the procedure, arguments, and lbp applying for that token when there is a "Left", an unclaimed parsed expression. In his paper, Pratt, V. R. Top Down Operator Precendence. `SIGACT/SIGPLAN Symposium on Principles of Programming Languages', Boston, 1973, pages 41-51 the "left binding power" (or "lbp") was an independent property of tokens. I think this was done in order to allow tokens with NUDs but not LEDs to also be used as delimiters, which was a problem for statically defined syntaxes. It turns out that *dynamically binding* NUDs and LEDs allows them independence. For the rule-defining procedures that follow, the variable TK may be a character, string, or symbol, or a list composed of characters, strings, and symbols. Each element of TK is treated as though the procedure were called for each element. Character TK arguments will match only character tokens; i.e. characters for which no token-group is assigned. Symbols and strings will both match token strings; i.e. tokens resulting from token groups. - Function: prec:make-nud TK SOP ARG1 ... Returns a rule specifying that SOP be called when TK is parsed. If SOP is a procedure, it is called with TK and ARG1 ... as its arguments; the resulting value is incorporated into the expression being built. Otherwise, `(list SOP ARG1 ...)' is incorporated. If no NUD has been defined for a token; then if that token is a string, it is converted to a symbol and returned; if not a string, the token is returned. - Function: prec:make-led TK SOP ARG1 ... Returns a rule specifying that SOP be called when TK is parsed and LEFT has an unclaimed parsed expression. If SOP is a procedure, it is called with LEFT, TK, and ARG1 ... as its arguments; the resulting value is incorporated into the expression being built. Otherwise, LEFT is incorporated. If no LED has been defined for a token, and LEFT is set, the parser issues a warning. File: slib.info, Node: Grammar Rule Definition, Prev: Nud and Led Definition, Up: Precedence Parsing Grammar Rule Definition ----------------------- Here are procedures for defining rules for the syntax types introduced in *Note Precedence Parsing Overview::. For the rule-defining procedures that follow, the variable TK may be a character, string, or symbol, or a list composed of characters, strings, and symbols. Each element of TK is treated as though the procedure were called for each element. For procedures prec:delim, ..., prec:prestfix, if the SOP argument is `#f', then the token which triggered this rule is converted to a symbol and returned. A false SOP argument to the procedures prec:commentfix, prec:matchfix, or prec:inmatchfix has a different meaning. Character TK arguments will match only character tokens; i.e. characters for which no token-group is assigned. Symbols and strings will both match token strings; i.e. tokens resulting from token groups. - Function: prec:delim TK Returns a rule specifying that TK should not be returned from parsing; i.e. TK's function is purely syntactic. The end-of-file is always treated as a delimiter. - Function: prec:nofix TK SOP Returns a rule specifying the following actions take place when TK is parsed: * If SOP is a procedure, it is called with no arguments; the resulting value is incorporated into the expression being built. Otherwise, the list of SOP is incorporated. - Function: prec:prefix TK SOP BP RULE1 ... Returns a rule specifying the following actions take place when TK is parsed: * The rules RULE1 ... augment and, in case of conflict, override rules currently in effect. * `prec:parse1' is called with binding-power BP. * If SOP is a procedure, it is called with the expression returned from `prec:parse1'; the resulting value is incorporated into the expression being built. Otherwise, the list of SOP and the expression returned from `prec:parse1' is incorporated. * The ruleset in effect before TK was parsed is restored; RULE1 ... are forgotten. - Function: prec:infix TK SOP LBP BP RULE1 ... Returns a rule declaring the left-binding-precedence of the token TK is LBP and specifying the following actions take place when TK is parsed: * The rules RULE1 ... augment and, in case of conflict, override rules currently in effect. * One expression is parsed with binding-power LBP. If instead a delimiter is encountered, a warning is issued. * If SOP is a procedure, it is applied to the list of LEFT and the parsed expression; the resulting value is incorporated into the expression being built. Otherwise, the list of SOP, the LEFT expression, and the parsed expression is incorporated. * The ruleset in effect before TK was parsed is restored; RULE1 ... are forgotten. - Function: prec:nary TK SOP BP Returns a rule declaring the left-binding-precedence of the token TK is BP and specifying the following actions take place when TK is parsed: * Expressions are parsed with binding-power BP as far as they are interleaved with the token TK. * If SOP is a procedure, it is applied to the list of LEFT and the parsed expressions; the resulting value is incorporated into the expression being built. Otherwise, the list of SOP, the LEFT expression, and the parsed expressions is incorporated. - Function: prec:postfix TK SOP LBP Returns a rule declaring the left-binding-precedence of the token TK is LBP and specifying the following actions take place when TK is parsed: * If SOP is a procedure, it is called with the LEFT expression; the resulting value is incorporated into the expression being built. Otherwise, the list of SOP and the LEFT expression is incorporated. - Function: prec:prestfix TK SOP BP RULE1 ... Returns a rule specifying the following actions take place when TK is parsed: * The rules RULE1 ... augment and, in case of conflict, override rules currently in effect. * Expressions are parsed with binding-power BP until a delimiter is reached. * If SOP is a procedure, it is applied to the list of parsed expressions; the resulting value is incorporated into the expression being built. Otherwise, the list of SOP and the parsed expressions is incorporated. * The ruleset in effect before TK was parsed is restored; RULE1 ... are forgotten. - Function: prec:commentfix TK STP MATCH RULE1 ... Returns rules specifying the following actions take place when TK is parsed: * The rules RULE1 ... augment and, in case of conflict, override rules currently in effect. * Characters are read until and end-of-file or a sequence of characters is read which matches the *string* MATCH. * If STP is a procedure, it is called with the string of all that was read between the TK and MATCH (exclusive). * The ruleset in effect before TK was parsed is restored; RULE1 ... are forgotten. Parsing of commentfix syntax differs from the others in several ways. It reads directly from input without tokenizing; It calls STP but does not return its value; nay any value. I added the STP argument so that comment text could be echoed. - Function: prec:matchfix TK SOP SEP MATCH RULE1 ... Returns a rule specifying the following actions take place when TK is parsed: * The rules RULE1 ... augment and, in case of conflict, override rules currently in effect. * A rule declaring the token MATCH a delimiter takes effect. * Expressions are parsed with binding-power `0' until the token MATCH is reached. If the token SEP does not appear between each pair of expressions parsed, a warning is issued. * If SOP is a procedure, it is applied to the list of parsed expressions; the resulting value is incorporated into the expression being built. Otherwise, the list of SOP and the parsed expressions is incorporated. * The ruleset in effect before TK was parsed is restored; RULE1 ... are forgotten. - Function: prec:inmatchfix TK SOP SEP MATCH LBP RULE1 ... Returns a rule declaring the left-binding-precedence of the token TK is LBP and specifying the following actions take place when TK is parsed: * The rules RULE1 ... augment and, in case of conflict, override rules currently in effect. * A rule declaring the token MATCH a delimiter takes effect. * Expressions are parsed with binding-power `0' until the token MATCH is reached. If the token SEP does not appear between each pair of expressions parsed, a warning is issued. * If SOP is a procedure, it is applied to the list of LEFT and the parsed expressions; the resulting value is incorporated into the expression being built. Otherwise, the list of SOP, the LEFT expression, and the parsed expressions is incorporated. * The ruleset in effect before TK was parsed is restored; RULE1 ... are forgotten. File: slib.info, Node: Format, Next: Standard Formatted I/O, Prev: Precedence Parsing, Up: Textual Conversion Packages Format (version 3.0) ==================== `(require 'format)' * Menu: * Format Interface:: * Format Specification:: File: slib.info, Node: Format Interface, Next: Format Specification, Prev: Format, Up: Format Format Interface ---------------- - Function: format DESTINATION FORMAT-STRING . ARGUMENTS An almost complete implementation of Common LISP format description according to the CL reference book `Common LISP' from Guy L. Steele, Digital Press. Backward compatible to most of the available Scheme format implementations. Returns `#t', `#f' or a string; has side effect of printing according to FORMAT-STRING. If DESTINATION is `#t', the output is to the current output port and `#t' is returned. If DESTINATION is `#f', a formatted string is returned as the result of the call. NEW: If DESTINATION is a string, DESTINATION is regarded as the format string; FORMAT-STRING is then the first argument and the output is returned as a string. If DESTINATION is a number, the output is to the current error port if available by the implementation. Otherwise DESTINATION must be an output port and `#t' is returned. FORMAT-STRING must be a string. In case of a formatting error format returns `#f' and prints a message on the current output or error port. Characters are output as if the string were output by the `display' function with the exception of those prefixed by a tilde (~). For a detailed description of the FORMAT-STRING syntax please consult a Common LISP format reference manual. For a test suite to verify this format implementation load `formatst.scm'. Please send bug reports to `lutzeb@cs.tu-berlin.de'. Note: `format' is not reentrant, i.e. only one `format'-call may be executed at a time. File: slib.info, Node: Format Specification, Prev: Format Interface, Up: Format Format Specification (Format version 3.0) ----------------------------------------- Please consult a Common LISP format reference manual for a detailed description of the format string syntax. For a demonstration of the implemented directives see `formatst.scm'. This implementation supports directive parameters and modifiers (`:' and `@' characters). Multiple parameters must be separated by a comma (`,'). Parameters can be numerical parameters (positive or negative), character parameters (prefixed by a quote character (`''), variable parameters (`v'), number of rest arguments parameter (`#'), empty and default parameters. Directive characters are case independent. The general form of a directive is: DIRECTIVE ::= ~{DIRECTIVE-PARAMETER,}[:][@]DIRECTIVE-CHARACTER DIRECTIVE-PARAMETER ::= [ [-|+]{0-9}+ | 'CHARACTER | v | # ] Implemented CL Format Control Directives ........................................ Documentation syntax: Uppercase characters represent the corresponding control directive characters. Lowercase characters represent control directive parameter descriptions. Any (print as `display' does). `~@A' left pad. `~MINCOL,COLINC,MINPAD,PADCHARA' full padding. S-expression (print as `write' does). `~@S' left pad. `~MINCOL,COLINC,MINPAD,PADCHARS' full padding. Decimal. `~@D' print number sign always. `~:D' print comma separated. `~MINCOL,PADCHAR,COMMACHARD' padding. Hexadecimal. `~@X' print number sign always. `~:X' print comma separated. `~MINCOL,PADCHAR,COMMACHARX' padding. Octal. `~@O' print number sign always. `~:O' print comma separated. `~MINCOL,PADCHAR,COMMACHARO' padding. Binary. `~@B' print number sign always. `~:B' print comma separated. `~MINCOL,PADCHAR,COMMACHARB' padding. `~NR' Radix N. `~N,MINCOL,PADCHAR,COMMACHARR' padding. `~@R' print a number as a Roman numeral. `~:@R' print a number as an "old fashioned" Roman numeral. `~:R' print a number as an ordinal English number. `~:@R' print a number as a cardinal English number. Plural. `~@P' prints `y' and `ies'. `~:P' as `~P but jumps 1 argument backward.' `~:@P' as `~@P but jumps 1 argument backward.' Character. `~@C' prints a character as the reader can understand it (i.e. `#\' prefixing). `~:C' prints a character as emacs does (eg. `^C' for ASCII 03). Fixed-format floating-point (prints a flonum like MMM.NNN). `~WIDTH,DIGITS,SCALE,OVERFLOWCHAR,PADCHARF' `~@F' If the number is positive a plus sign is printed. Exponential floating-point (prints a flonum like MMM.NNN`E'EE). `~WIDTH,DIGITS,EXPONENTDIGITS,SCALE,OVERFLOWCHAR,PADCHAR,EXPONENTCHARE' `~@E' If the number is positive a plus sign is printed. General floating-point (prints a flonum either fixed or exponential). `~WIDTH,DIGITS,EXPONENTDIGITS,SCALE,OVERFLOWCHAR,PADCHAR,EXPONENTCHARG' `~@G' If the number is positive a plus sign is printed. Dollars floating-point (prints a flonum in fixed with signs separated). `~DIGITS,SCALE,WIDTH,PADCHAR$' `~@$' If the number is positive a plus sign is printed. `~:@$' A sign is always printed and appears before the padding. `~:$' The sign appears before the padding. Newline. `~N%' print N newlines. print newline if not at the beginning of the output line. `~N&' prints `~&' and then N-1 newlines. Page Separator. `~N|' print N page separators. Tilde. `~N~' print N tildes. `~'<newline> Continuation Line. `~:'<newline> newline is ignored, white space left. `~@'<newline> newline is left, white space ignored. Tabulation. `~@T' relative tabulation. `~COLNUM,COLINCT' full tabulation. Indirection (expects indirect arguments as a list). `~@?' extracts indirect arguments from format arguments. `~(STR~)' Case conversion (converts by `string-downcase'). `~:(STR~)' converts by `string-capitalize'. `~@(STR~)' converts by `string-capitalize-first'. `~:@(STR~)' converts by `string-upcase'. Argument Jumping (jumps 1 argument forward). `~N*' jumps N arguments forward. `~:*' jumps 1 argument backward. `~N:*' jumps N arguments backward. `~@*' jumps to the 0th argument. `~N@*' jumps to the Nth argument (beginning from 0) `~[STR0~;STR1~;...~;STRN~]' Conditional Expression (numerical clause conditional). `~N[' take argument from N. `~@[' true test conditional. `~:[' if-else-then conditional. `~;' clause separator. `~:;' default clause follows. `~{STR~}' Iteration (args come from the next argument (a list)). `~N{' at most N iterations. `~:{' args from next arg (a list of lists). `~@{' args from the rest of arguments. `~:@{' args from the rest args (lists). Up and out. `~N^' aborts if N = 0 `~N,M^' aborts if N = M `~N,M,K^' aborts if N <= M <= K Not Implemented CL Format Control Directives ............................................ `~:A' print `#f' as an empty list (see below). `~:S' print `#f' as an empty list (see below). `~<~>' Justification. `~:^' (sorry I don't understand its semantics completely) Extended, Replaced and Additional Control Directives .................................................... `~MINCOL,PADCHAR,COMMACHAR,COMMAWIDTHD' `~MINCOL,PADCHAR,COMMACHAR,COMMAWIDTHX' `~MINCOL,PADCHAR,COMMACHAR,COMMAWIDTHO' `~MINCOL,PADCHAR,COMMACHAR,COMMAWIDTHB' `~N,MINCOL,PADCHAR,COMMACHAR,COMMAWIDTHR' COMMAWIDTH is the number of characters between two comma characters. print a R4RS complex number as `~F~@Fi' with passed parameters for `~F'. Pretty print formatting of an argument for scheme code lists. Same as `~?.' Flushes the output if format DESTINATION is a port. Print a `#\space' character `~N_' print N `#\space' characters. Print a `#\tab' character `~N/' print N `#\tab' characters. `~NC' Takes N as an integer representation for a character. No arguments are consumed. N is converted to a character by `integer->char'. N must be a positive decimal number. `~:S' Print out readproof. Prints out internal objects represented as `#<...>' as strings `"#<...>"' so that the format output can always be processed by `read'. `~:A' Print out readproof. Prints out internal objects represented as `#<...>' as strings `"#<...>"' so that the format output can always be processed by `read'. Prints information and a copyright notice on the format implementation. `~:Q' prints format version. `~F, ~E, ~G, ~$' may also print number strings, i.e. passing a number as a string and format it accordingly. Configuration Variables ....................... Format has some configuration variables at the beginning of `format.scm' to suit the systems and users needs. There should be no modification necessary for the configuration that comes with SLIB. If modification is desired the variable should be set after the format code is loaded. Format detects automatically if the running scheme system implements floating point numbers and complex numbers. FORMAT:SYMBOL-CASE-CONV Symbols are converted by `symbol->string' so the case type of the printed symbols is implementation dependent. `format:symbol-case-conv' is a one arg closure which is either `#f' (no conversion), `string-upcase', `string-downcase' or `string-capitalize'. (default `#f') FORMAT:IOBJ-CASE-CONV As FORMAT:SYMBOL-CASE-CONV but applies for the representation of implementation internal objects. (default `#f') FORMAT:EXPCH The character prefixing the exponent value in `~E' printing. (default `#\E') Compatibility With Other Format Implementations ............................................... SLIB format 2.x: See `format.doc'. SLIB format 1.4: Downward compatible except for padding support and `~A', `~S', `~P', `~X' uppercase printing. SLIB format 1.4 uses C-style `printf' padding support which is completely replaced by the CL `format' padding style. MIT C-Scheme 7.1: Downward compatible except for `~', which is not documented (ignores all characters inside the format string up to a newline character). (7.1 implements `~a', `~s', ~NEWLINE, `~~', `~%', numerical and variable parameters and `:/@' modifiers in the CL sense). Elk 1.5/2.0: Downward compatible except for `~A' and `~S' which print in uppercase. (Elk implements `~a', `~s', `~~', and `~%' (no directive parameters or modifiers)). Scheme->C 01nov91: Downward compatible except for an optional destination parameter: S2C accepts a format call without a destination which returns a formatted string. This is equivalent to a #f destination in S2C. (S2C implements `~a', `~s', `~c', `~%', and `~~' (no directive parameters or modifiers)). This implementation of format is solely useful in the SLIB context because it requires other components provided by SLIB. File: slib.info, Node: Standard Formatted I/O, Next: Programs and Arguments, Prev: Format, Up: Textual Conversion Packages Standard Formatted I/O ====================== * Menu: * Standard Formatted Output:: 'printf * Standard Formatted Input:: 'scanf stdio ----- `(require 'stdio)' `require's `printf' and `scanf' and additionally defines the symbols: - Variable: stdin Defined to be `(current-input-port)'. - Variable: stdout Defined to be `(current-output-port)'. - Variable: stderr Defined to be `(current-error-port)'. File: slib.info, Node: Standard Formatted Output, Next: Standard Formatted Input, Prev: Standard Formatted I/O, Up: Standard Formatted I/O Standard Formatted Output ------------------------- `(require 'printf)' - Procedure: printf FORMAT ARG1 ... - Procedure: fprintf PORT FORMAT ARG1 ... - Procedure: sprintf STR FORMAT ARG1 ... - Procedure: sprintf #F FORMAT ARG1 ... - Procedure: sprintf K FORMAT ARG1 ... Each function converts, formats, and outputs its ARG1 ... arguments according to the control string FORMAT argument and returns the number of characters output. `printf' sends its output to the port `(current-output-port)'. `fprintf' sends its output to the port PORT. `sprintf' `string-set!'s locations of the non-constant string argument STR to the output characters. Two extensions of `sprintf' return new strings. If the first argument is `#f', then the returned string's length is as many characters as specified by the FORMAT and data; if the first argument is a non-negative integer K, then the length of the returned string is also bounded by K. The string FORMAT contains plain characters which are copied to the output stream, and conversion specifications, each of which results in fetching zero or more of the arguments ARG1 .... The results are undefined if there are an insufficient number of arguments for the format. If FORMAT is exhausted while some of the ARG1 ... arguments remain unused, the excess ARG1 ... arguments are ignored. The conversion specifications in a format string have the form: % [ FLAGS ] [ WIDTH ] [ . PRECISION ] [ TYPE ] CONVERSION An output conversion specifications consist of an initial `%' character followed in sequence by: * Zero or more "flag characters" that modify the normal behavior of the conversion specification. `-' Left-justify the result in the field. Normally the result is right-justified. `+' For the signed `%d' and `%i' conversions and all inexact conversions, prefix a plus sign if the value is positive. ` ' For the signed `%d' and `%i' conversions, if the result doesn't start with a plus or minus sign, prefix it with a space character instead. Since the `+' flag ensures that the result includes a sign, this flag is ignored if both are specified. `#' For inexact conversions, `#' specifies that the result should always include a decimal point, even if no digits follow it. For the `%g' and `%G' conversions, this also forces trailing zeros after the decimal point to be printed where they would otherwise be elided. For the `%o' conversion, force the leading digit to be `0', as if by increasing the precision. For `%x' or `%X', prefix a leading `0x' or `0X' (respectively) to the result. This doesn't do anything useful for the `%d', `%i', or `%u' conversions. Using this flag produces output which can be parsed by the `scanf' functions with the `%i' conversion (*note Standard Formatted Input::.). `0' Pad the field with zeros instead of spaces. The zeros are placed after any indication of sign or base. This flag is ignored if the `-' flag is also specified, or if a precision is specified for an exact converson. * An optional decimal integer specifying the "minimum field width". If the normal conversion produces fewer characters than this, the field is padded (with spaces or zeros per the `0' flag) to the specified width. This is a *minimum* width; if the normal conversion produces more characters than this, the field is *not* truncated. Alternatively, if the field width is `*', the next argument in the argument list (before the actual value to be printed) is used as the field width. The width value must be an integer. If the value is negative it is as though the `-' flag is set (see above) and the absolute value is used as the field width. * An optional "precision" to specify the number of digits to be written for numeric conversions and the maximum field width for string conversions. The precision is specified by a period (`.') followed optionally by a decimal integer (which defaults to zero if omitted). Alternatively, if the precision is `.*', the next argument in the argument list (before the actual value to be printed) is used as the precision. The value must be an integer, and is ignored if negative. If you specify `*' for both the field width and precision, the field width argument precedes the precision argument. The `.*' precision is an enhancement. C library versions may not accept this syntax. For the `%f', `%e', and `%E' conversions, the precision specifies how many digits follow the decimal-point character. The default precision is `6'. If the precision is explicitly `0', the decimal point character is suppressed. For the `%g' and `%G' conversions, the precision specifies how many significant digits to print. Significant digits are the first digit before the decimal point, and all the digits after it. If the precision is `0' or not specified for `%g' or `%G', it is treated like a value of `1'. If the value being printed cannot be expressed accurately in the specified number of digits, the value is rounded to the nearest number that fits. For exact conversions, if a precision is supplied it specifies the minimum number of digits to appear; leading zeros are produced if necessary. If a precision is not supplied, the number is printed with as many digits as necessary. Converting an exact `0' with an explicit precision of zero produces no characters. * An optional one of `l', `h' or `L', which is ignored for numeric conversions. It is an error to specify these modifiers for non-numeric conversions. * A character that specifies the conversion to be applied. Exact Conversions ................. `d', `i' Print an integer as a signed decimal number. `%d' and `%i' are synonymous for output, but are different when used with `scanf' for input (*note Standard Formatted Input::.). `o' Print an integer as an unsigned octal number. `u' Print an integer as an unsigned decimal number. `x', `X' Print an integer as an unsigned hexadecimal number. `%x' prints using the digits `0123456789abcdef'. `%X' prints using the digits `0123456789ABCDEF'. Inexact Conversions ................... `f' Print a floating-point number in fixed-point notation. `e', `E' Print a floating-point number in exponential notation. `%e' prints `e' between mantissa and exponont. `%E' prints `E' between mantissa and exponont. `g', `G' Print a floating-point number in either normal or exponential notation, whichever is more appropriate for its magnitude. Unless an `#' flag has been supplied trailing zeros after a decimal point will be stripped off. `%g' prints `e' between mantissa and exponont. `%G' prints `E' between mantissa and exponent. Other Conversions ................. `c' Print a single character. The `-' flag is the only one which can be specified. It is an error to specify a precision. `s' Print a string. The `-' flag is the only one which can be specified. A precision specifies the maximum number of characters to output; otherwise all characters in the string are output. `a', `A' Print a scheme expression. The `-' flag left-justifies the output. The `#' flag specifies that strings and characters should be quoted as by `write' (which can be read using `read'); otherwise, output is as `display' prints. A precision specifies the maximum number of characters to output; otherwise as many characters as needed are output. *Note:* `%a' and `%A' are SLIB extensions. `%' Print a literal `%' character. No argument is consumed. It is an error to specifiy flags, field width, precision, or type modifiers with `%%'. File: slib.info, Node: Standard Formatted Input, Prev: Standard Formatted Output, Up: Standard Formatted I/O Standard Formatted Input ------------------------ `(require 'scanf)' - Function: scanf-read-list FORMAT - Function: scanf-read-list FORMAT PORT - Function: scanf-read-list FORMAT STRING - Macro: scanf FORMAT ARG1 ... - Macro: fscanf PORT FORMAT ARG1 ... - Macro: sscanf STR FORMAT ARG1 ... Each function reads characters, interpreting them according to the control string FORMAT argument. `scanf-read-list' returns a list of the items specified as far as the input matches FORMAT. `scanf', `fscanf', and `sscanf' return the number of items successfully matched and stored. `scanf', `fscanf', and `sscanf' also set the location corresponding to ARG1 ... using the methods: symbol `set!' car expression `set-car!' cdr expression `set-cdr!' vector-ref expression `vector-set!' substring expression `substring-move-left!' The argument to a `substring' expression in ARG1 ... must be a non-constant string. Characters will be stored starting at the position specified by the second argument to `substring'. The number of characters stored will be limited by either the position specified by the third argument to `substring' or the length of the matched string, whichever is less. The control string, FORMAT, contains conversion specifications and other characters used to direct interpretation of input sequences. The control string contains: * White-space characters (blanks, tabs, newlines, or formfeeds) that cause input to be read (and discarded) up to the next non-white-space character. * An ordinary character (not `%') that must match the next character of the input stream. * Conversion specifications, consisting of the character `%', an optional assignment suppressing character `*', an optional numerical maximum-field width, an optional `l', `h' or `L' which is ignored, and a conversion code. Unless the specification contains the `n' conversion character (described below), a conversion specification directs the conversion of the next input field. The result of a conversion specification is returned in the position of the corresponding argument points, unless `*' indicates assignment suppression. Assignment suppression provides a way to describe an input field to be skipped. An input field is defined as a string of characters; it extends to the next inappropriate character or until the field width, if specified, is exhausted. *Note:* This specification of format strings differs from the `ANSI C' and `POSIX' specifications. In SLIB, white space before an input field is not skipped unless white space appears before the conversion specification in the format string. In order to write format strings which work identically with `ANSI C' and SLIB, prepend whitespace to all conversion specifications except `[' and `c'. The conversion code indicates the interpretation of the input field; For a suppressed field, no value is returned. The following conversion codes are legal: `%' A single % is expected in the input at this point; no value is returned. `d', `D' A decimal integer is expected. `u', `U' An unsigned decimal integer is expected. `o', `O' An octal integer is expected. `x', `X' A hexadecimal integer is expected. `i' An integer is expected. Returns the value of the next input item, interpreted according to C conventions; a leading `0' implies octal, a leading `0x' implies hexadecimal; otherwise, decimal is assumed. `n' Returns the total number of bytes (including white space) read by `scanf'. No input is consumed by `%n'. `f', `F', `e', `E', `g', `G' A floating-point number is expected. The input format for floating-point numbers is an optionally signed string of digits, possibly containing a radix character `.', followed by an optional exponent field consisting of an `E' or an `e', followed by an optional `+', `-', or space, followed by an integer. `c', `C' WIDTH characters are expected. The normal skip-over-white-space is suppressed in this case; to read the next non-space character, use `%1s'. If a field width is given, a string is returned; up to the indicated number of characters is read. `s', `S' A character string is expected The input field is terminated by a white-space character. `scanf' cannot read a null string. `[' Indicates string data and the normal skip-over-leading-white-space is suppressed. The left bracket is followed by a set of characters, called the scanset, and a right bracket; the input field is the maximal sequence of input characters consisting entirely of characters in the scanset. `^', when it appears as the first character in the scanset, serves as a complement operator and redefines the scanset as the set of all characters not contained in the remainder of the scanset string. Construction of the scanset follows certain conventions. A range of characters may be represented by the construct first-last, enabling `[0123456789]' to be expressed `[0-9]'. Using this convention, first must be lexically less than or equal to last; otherwise, the dash stands for itself. The dash also stands for itself when it is the first or the last character in the scanset. To include the right square bracket as an element of the scanset, it must appear as the first character (possibly preceded by a `^') of the scanset, in which case it will not be interpreted syntactically as the closing bracket. At least one character must match for this conversion to succeed. The `scanf' functions terminate their conversions at end-of-file, at the end of the control string, or when an input character conflicts with the control string. In the latter case, the offending character is left unread in the input stream. File: slib.info, Node: Programs and Arguments, Next: HTML HTTP and CGI, Prev: Standard Formatted I/O, Up: Textual Conversion Packages Program and Arguments ===================== * Menu: * Getopt:: Command Line option parsing * Command Line:: A command line reader for Scheme shells * Parameter lists:: 'parameters * Getopt Parameter lists:: 'getopt-parameters * Filenames:: 'glob or 'filename * Batch:: 'batch File: slib.info, Node: Getopt, Next: Command Line, Prev: Programs and Arguments, Up: Programs and Arguments Getopt ------ `(require 'getopt)' This routine implements Posix command line argument parsing. Notice that returning values through global variables means that `getopt' is *not* reentrant. - Variable: *optind* Is the index of the current element of the command line. It is initially one. In order to parse a new command line or reparse an old one, *OPTING* must be reset. - Variable: *optarg* Is set by getopt to the (string) option-argument of the current option. - Procedure: getopt ARGC ARGV OPTSTRING Returns the next option letter in ARGV (starting from `(vector-ref argv *optind*)') that matches a letter in OPTSTRING. ARGV is a vector or list of strings, the 0th of which getopt usually ignores. ARGC is the argument count, usually the length of ARGV. OPTSTRING is a string of recognized option characters; if a character is followed by a colon, the option takes an argument which may be immediately following it in the string or in the next element of ARGV. *OPTIND* is the index of the next element of the ARGV vector to be processed. It is initialized to 1 by `getopt.scm', and `getopt' updates it when it finishes with each element of ARGV. `getopt' returns the next option character from ARGV that matches a character in OPTSTRING, if there is one that matches. If the option takes an argument, `getopt' sets the variable *OPTARG* to the option-argument as follows: * If the option was the last character in the string pointed to by an element of ARGV, then *OPTARG* contains the next element of ARGV, and *OPTIND* is incremented by 2. If the resulting value of *OPTIND* is greater than or equal to ARGC, this indicates a missing option argument, and `getopt' returns an error indication. * Otherwise, *OPTARG* is set to the string following the option character in that element of ARGV, and *OPTIND* is incremented by 1. If, when `getopt' is called, the string `(vector-ref argv *optind*)' either does not begin with the character `#\-' or is just `"-"', `getopt' returns `#f' without changing *OPTIND*. If `(vector-ref argv *optind*)' is the string `"--"', `getopt' returns `#f' after incrementing *OPTIND*. If `getopt' encounters an option character that is not contained in OPTSTRING, it returns the question-mark `#\?' character. If it detects a missing option argument, it returns the colon character `#\:' if the first character of OPTSTRING was a colon, or a question-mark character otherwise. In either case, `getopt' sets the variable GETOPT:OPT to the option character that caused the error. The special option `"--"' can be used to delimit the end of the options; `#f' is returned, and `"--"' is skipped. RETURN VALUE `getopt' returns the next option character specified on the command line. A colon `#\:' is returned if `getopt' detects a missing argument and the first character of OPTSTRING was a colon `#\:'. A question-mark `#\?' is returned if `getopt' encounters an option character not in OPTSTRING or detects a missing argument and the first character of OPTSTRING was not a colon `#\:'. Otherwise, `getopt' returns `#f' when all command line options have been parsed. Example: #! /usr/local/bin/scm ;;;This code is SCM specific. (define argv (program-arguments)) (require 'getopt) (define opts ":a:b:cd") (let loop ((opt (getopt (length argv) argv opts))) (case opt ((#\a) (print "option a: " *optarg*)) ((#\b) (print "option b: " *optarg*)) ((#\c) (print "option c")) ((#\d) (print "option d")) ((#\?) (print "error" getopt:opt)) ((#\:) (print "missing arg" getopt:opt)) ((#f) (if (< *optind* (length argv)) (print "argv[" *optind* "]=" (list-ref argv *optind*))) (set! *optind* (+ *optind* 1)))) (if (< *optind* (length argv)) (loop (getopt (length argv) argv opts)))) (slib:exit) Getopt- ------- - Function: getopt- ARGC ARGV OPTSTRING The procedure `getopt--' is an extended version of `getopt' which parses "long option names" of the form `--hold-the-onions' and `--verbosity-level=extreme'. `Getopt--' behaves as `getopt' except for non-empty options beginning with `--'. Options beginning with `--' are returned as strings rather than characters. If a value is assigned (using `=') to a long option, `*optarg*' is set to the value. The `=' and value are not returned as part of the option string. No information is passed to `getopt--' concerning which long options should be accepted or whether such options can take arguments. If a long option did not have an argument, `*optarg' will be set to `#f'. The caller is responsible for detecting and reporting errors. (define opts ":-:b:") (define argc 5) (define argv '("foo" "-b9" "--f1" "--2=" "--g3=35234.342" "--")) (define *optind* 1) (define *optarg* #f) (require 'qp) (do ((i 5 (+ -1 i))) ((zero? i)) (define opt (getopt-- argc argv opts)) (print *optind* opt *optarg*))) -| 2 #\b "9" 3 "f1" #f 4 "2" "" 5 "g3" "35234.342" 5 #f "35234.342" File: slib.info, Node: Command Line, Next: Parameter lists, Prev: Getopt, Up: Programs and Arguments Command Line ------------ `(require 'read-command)' - Function: read-command PORT - Function: read-command `read-command' converts a "command line" into a list of strings suitable for parsing by `getopt'. The syntax of command lines supported resembles that of popular "shell"s. `read-command' updates PORT to point to the first character past the command delimiter. If an end of file is encountered in the input before any characters are found that can begin an object or comment, then an end of file object is returned. The PORT argument may be omitted, in which case it defaults to the value returned by `current-input-port'. The fields into which the command line is split are delimited by whitespace as defined by `char-whitespace?'. The end of a command is delimited by end-of-file or unescaped semicolon (<;>) or <newline>. Any character can be literally included in a field by escaping it with a backslach (<\>). The initial character and types of fields recognized are: `\' The next character has is taken literally and not interpreted as a field delimiter. If <\> is the last character before a <newline>, that <newline> is just ignored. Processing continues from the characters after the <newline> as though the backslash and <newline> were not there. `"' The characters up to the next unescaped <"> are taken literally, according to [R4RS] rules for literal strings (*note Strings: (r4rs)Strings.). `(', `%'' One scheme expression is `read' starting with this character. The `read' expression is evaluated, converted to a string (using `display'), and replaces the expression in the returned field. `;' Semicolon delimits a command. Using semicolons more than one command can appear on a line. Escaped semicolons and semicolons inside strings do not delimit commands. The comment field differs from the previous fields in that it must be the first character of a command or appear after whitespace in order to be recognized. <#> can be part of fields if these conditions are not met. For instance, `ab#c' is just the field ab#c. `#' Introduces a comment. The comment continues to the end of the line on which the semicolon appears. Comments are treated as whitespace by `read-dommand-line' and backslashes before <newline>s in comments are also ignored. - Function: read-options-file FILENAME `read-options-file' converts an "options file" into a list of strings suitable for parsing by `getopt'. The syntax of options files is the same as the syntax for command lines, except that <newline>s do not terminate reading (only <;> or end of file). If an end of file is encountered before any characters are found that can begin an object or comment, then an end of file object is returned. File: slib.info, Node: Parameter lists, Next: Getopt Parameter lists, Prev: Command Line, Up: Programs and Arguments Parameter lists --------------- `(require 'parameters)' Arguments to procedures in scheme are distinguished from each other by their position in the procedure call. This can be confusing when a procedure takes many arguments, many of which are not often used. A "parameter-list" is a way of passing named information to a procedure. Procedures are also defined to set unused parameters to default values, check parameters, and combine parameter lists. A PARAMETER has the form `(parameter-name value1 ...)'. This format allows for more than one value per parameter-name. A PARAMETER-LIST is a list of PARAMETERs, each with a different PARAMETER-NAME. - Function: make-parameter-list PARAMETER-NAMES Returns an empty parameter-list with slots for PARAMETER-NAMES. - Function: parameter-list-ref PARAMETER-LIST PARAMETER-NAME PARAMETER-NAME must name a valid slot of PARAMETER-LIST. `parameter-list-ref' returns the value of parameter PARAMETER-NAME of PARAMETER-LIST. - Procedure: adjoin-parameters! PARAMETER-LIST PARAMETER1 ... Returns PARAMETER-LIST with PARAMETER1 ... merged in. - Procedure: parameter-list-expand EXPANDERS PARAMETER-LIST EXPANDERS is a list of procedures whose order matches the order of the PARAMETER-NAMEs in the call to `make-parameter-list' which created PARAMETER-LIST. For each non-false element of EXPANDERS that procedure is mapped over the corresponding parameter value and the returned parameter lists are merged into PARAMETER-LIST. This process is repeated until PARAMETER-LIST stops growing. The value returned from `parameter-list-expand' is unspecified. - Function: fill-empty-parameters DEFAULTERS PARAMETER-LIST DEFAULTERS is a list of procedures whose order matches the order of the PARAMETER-NAMEs in the call to `make-parameter-list' which created PARAMETER-LIST. `fill-empty-parameters' returns a new parameter-list with each empty parameter replaced with the list returned by calling the corresponding DEFAULTER with PARAMETER-LIST as its argument. - Function: check-parameters CHECKS PARAMETER-LIST CHECKS is a list of procedures whose order matches the order of the PARAMETER-NAMEs in the call to `make-parameter-list' which created PARAMETER-LIST. `check-parameters' returns PARAMETER-LIST if each CHECK of the corresponding PARAMETER-LIST returns non-false. If some CHECK returns `#f' an error is signaled. In the following procedures ARITIES is a list of symbols. The elements of `arities' can be: `single' Requires a single parameter. `optional' A single parameter or no parameter is acceptable. `boolean' A single boolean parameter or zero parameters is acceptable. `nary' Any number of parameters are acceptable. `nary1' One or more of parameters are acceptable. - Function: parameter-list->arglist POSITIONS ARITIES TYPES PARAMETER-LIST Returns PARAMETER-LIST converted to an argument list. Parameters of ARITY type `single' and `boolean' are converted to the single value associated with them. The other ARITY types are converted to lists of the value(s) of type TYPES. POSITIONS is a list of positive integers whose order matches the order of the PARAMETER-NAMEs in the call to `make-parameter-list' which created PARAMETER-LIST. The integers specify in which argument position the corresponding parameter should appear. File: slib.info, Node: Getopt Parameter lists, Next: Filenames, Prev: Parameter lists, Up: Programs and Arguments Getopt Parameter lists ---------------------- `(require 'getopt-parameters)' - Function: getopt->parameter-list ARGC ARGV OPTNAMES ARITIES TYPES ALIASES Returns ARGV converted to a parameter-list. OPTNAMES are the parameter-names. ALIASES is a list of lists of strings and elements of OPTNAMES. Each of these strings which have length of 1 will be treated as a single <-> option by `getopt'. Longer strings will be treated as long-named options (*note getopt-: Getopt.). - Function: getopt->arglist ARGC ARGV OPTNAMES POSITIONS ARITIES TYPES DEFAULTERS CHECKS ALIASES Like `getopt->parameter-list', but converts ARGV to an argument-list as specified by OPTNAMES, POSITIONS, ARITIES, TYPES, DEFAULTERS, CHECKS, and ALIASES. These `getopt' functions can be used with SLIB relational databases. For an example, *Note make-command-server: Database Utilities. If errors are encountered while processing options, directions for using the options are printed to `current-error-port'. (begin (set! *optind* 1) (getopt->parameter-list 2 '("cmd" "-?") '(flag number symbols symbols string flag2 flag3 num2 num3) '(boolean optional nary1 nary single boolean boolean nary nary) '(boolean integer symbol symbol string boolean boolean integer integer) '(("flag" flag) ("f" flag) ("Flag" flag2) ("B" flag3) ("optional" number) ("o" number) ("nary1" symbols) ("N" symbols) ("nary" symbols) ("n" symbols) ("single" string) ("s" string) ("a" num2) ("Abs" num3)))) -| Usage: cmd [OPTION ARGUMENT ...] ... -f, --flag -o, --optional=<number> -n, --nary=<symbols> ... -N, --nary1=<symbols> ... -s, --single=<string> --Flag -B -a <num2> ... --Abs=<num3> ... ERROR: getopt->parameter-list "unrecognized option" "-?" File: slib.info, Node: Filenames, Next: Batch, Prev: Getopt Parameter lists, Up: Programs and Arguments Filenames --------- `(require 'filename)' or `(require 'glob)' - Function: filename:match?? PATTERN - Function: filename:match-ci?? PATTERN Returns a predicate which returns a non-false value if its string | argument matches (the string) PATTERN, false otherwise. Filename | matching is like "glob" expansion described the bash manpage, | except that names beginning with `.' are matched and `/' | characters are not treated specially. | These functions interpret the following characters specially in PATTERN strings: `*' Matches any string, including the null string. `?' Matches any single character. `[...]' Matches any one of the enclosed characters. A pair of characters separated by a minus sign (-) denotes a range; any character lexically between those two characters, inclusive, is matched. If the first character following the `[' is a `!' or a `^' then any character not enclosed is matched. A `-' or `]' may be matched by including it as the first or last character in the set. - Function: filename:substitute?? PATTERN TEMPLATE | - Function: filename:substitute-ci?? PATTERN TEMPLATE | Returns a function transforming a single string argument according | to glob patterns PATTERN and TEMPLATE. PATTERN and TEMPLATE must | have the same number of wildcard specifications, which need not be | identical. PATTERN and TEMPLATE may have a different number of | literal sections. If an argument to the function matches PATTERN | in the sense of `filename:match??' then it returns a copy of | TEMPLATE in which each wildcard specification is replaced by the | part of the argument matched by the corresponding wildcard | specification in PATTERN. A `*' wildcard matches the longest | leftmost string possible. If the argument does not match PATTERN | then false is returned. | | ((filename:substitute?? "scm_[0-9]*.html" "scm5c4_??.htm") | "scm_10.html") | => "scm5c4_10.htm" | ((filename:substitute?? "??" "beg?mid?end") "AZ") | => "begAmidZend" | ((filename:substitute?? "*na*" "?NA?") "banana") | => "banaNA" | - Function: replace-suffix STR OLD NEW STR can be a string or a list of strings. Returns a new string (or strings) similar to `str' but with the suffix string OLD removed and the suffix string NEW appended. If the end of STR does not match OLD, an error is signaled. (replace-suffix "/usr/local/lib/slib/batch.scm" ".scm" ".c") => "/usr/local/lib/slib/batch.c" File: slib.info, Node: Batch, Prev: Filenames, Up: Programs and Arguments Batch ----- `(require 'batch)' The batch procedures provide a way to write and execute portable scripts for a variety of operating systems. Each `batch:' procedure takes as its first argument a parameter-list (*note Parameter lists::.). This parameter-list argument PARMS contains named associations. Batch currently uses 2 of these: `batch-port' The port on which to write lines of the batch file. `batch-dialect' The syntax of batch file to generate. Currently supported are: * unix * dos * vms * amigados | | * system * *unknown* `batch.scm' uses 2 enhanced relational tables (*note Database Utilities::.) to store information linking the names of `operating-system's to `batch-dialect'es. - Function: batch:initialize! DATABASE Defines `operating-system' and `batch-dialect' tables and adds the domain `operating-system' to the enhanced relational database DATABASE. - Variable: batch:platform Is batch's best guess as to which operating-system it is running under. `batch:platform' is set to `(software-type)' (*note Configuration::.) unless `(software-type)' is `unix', in which case finer distinctions are made. - Function: batch:call-with-output-script PARMS FILE PROC PROC should be a procedure of one argument. If FILE is an output-port, `batch:call-with-output-script' writes an appropriate header to FILE and then calls PROC with FILE as the only argument. If FILE is a string, `batch:call-with-output-script' opens a output-file of name FILE, writes an appropriate header to FILE, and then calls PROC with the newly opened port as the only argument. Otherwise, `batch:call-with-output-script' acts as if it was called with the result of `(current-output-port)' as its third argument. - Function: batch:apply-chop-to-fit PROC ARG1 ARG2 ... LIST The procedure PROC must accept at least one argument and return `#t' if successful, `#f' if not. `batch:apply-chop-to-fit' calls PROC with ARG1, ARG2, ..., and CHUNK, where CHUNK is a subset of LIST. `batch:apply-chop-to-fit' tries PROC with successively smaller subsets of LIST until either PROC returns non-false, or the CHUNKs become empty. The rest of the `batch:' procedures write (or execute if `batch-dialect' is `system') commands to the batch port which has been added to PARMS or `(copy-tree PARMS)' by the code: (adjoin-parameters! PARMS (list 'batch-port PORT)) - Function: batch:system PARMS STRING1 STRING2 ... Calls `batch:try-system' (below) with arguments, but signals an error if `batch:try-system' returns `#f'. These functions return a non-false value if the command was successfully translated into the batch dialect and `#f' if not. In the case of the `system' dialect, the value is non-false if the operation suceeded. - Function: batch:try-system PARMS STRING1 STRING2 ... Writes a command to the `batch-port' in PARMS which executes the program named STRING1 with arguments STRING2 .... - Function: batch:run-script PARMS STRING1 STRING2 ... Writes a command to the `batch-port' in PARMS which executes the batch script named STRING1 with arguments STRING2 .... *Note:* `batch:run-script' and `batch:try-system' are not the same for some operating systems (VMS). - Function: batch:comment PARMS LINE1 ... Writes comment lines LINE1 ... to the `batch-port' in PARMS. - Function: batch:lines->file PARMS FILE LINE1 ... Writes commands to the `batch-port' in PARMS which create a file named FILE with contents LINE1 .... - Function: batch:delete-file PARMS FILE Writes a command to the `batch-port' in PARMS which deletes the file named FILE. - Function: batch:rename-file PARMS OLD-NAME NEW-NAME Writes a command to the `batch-port' in PARMS which renames the file OLD-NAME to NEW-NAME. In addition, batch provides some small utilities very useful for writing scripts: - Function: truncate-up-to PATH CHAR - Function: truncate-up-to PATH STRING - Function: truncate-up-to PATH CHARLIST PATH can be a string or a list of strings. Returns PATH sans any prefixes ending with a character of the second argument. This can be used to derive a filename moved locally from elsewhere. (truncate-up-to "/usr/local/lib/slib/batch.scm" "/") => "batch.scm" - Function: string-join JOINER STRING1 ... Returns a new string consisting of all the strings STRING1 ... in order appended together with the string JOINER between each adjacent pair. - Function: must-be-first LIST1 LIST2 Returns a new list consisting of the elements of LIST2 ordered so that if some elements of LIST1 are `equal?' to elements of LIST2, then those elements will appear first and in the order of LIST1. - Function: must-be-last LIST1 LIST2 Returns a new list consisting of the elements of LIST1 ordered so that if some elements of LIST2 are `equal?' to elements of LIST1, then those elements will appear last and in the order of LIST2. - Function: os->batch-dialect OSNAME Returns its best guess for the `batch-dialect' to be used for the operating-system named OSNAME. `os->batch-dialect' uses the tables added to DATABASE by `batch:initialize!'. Here is an example of the use of most of batch's procedures: (require 'database-utilities) (require 'parameters) (require 'batch) (require 'glob) (define batch (create-database #f 'alist-table)) (batch:initialize! batch) (define my-parameters (list (list 'batch-dialect (os->batch-dialect batch:platform)) (list 'platform batch:platform) (list 'batch-port (current-output-port)))) ;gets filled in later (batch:call-with-output-script my-parameters "my-batch" (lambda (batch-port) (adjoin-parameters! my-parameters (list 'batch-port batch-port)) (and (batch:comment my-parameters "================ Write file with C program.") (batch:rename-file my-parameters "hello.c" "hello.c~") (batch:lines->file my-parameters "hello.c" "#include <stdio.h>" "int main(int argc, char **argv)" "{" " printf(\"hello world\\n\");" " return 0;" "}" ) (batch:system my-parameters "cc" "-c" "hello.c") (batch:system my-parameters "cc" "-o" "hello" (replace-suffix "hello.c" ".c" ".o")) (batch:system my-parameters "hello") (batch:delete-file my-parameters "hello") (batch:delete-file my-parameters "hello.c") (batch:delete-file my-parameters "hello.o") (batch:delete-file my-parameters "my-batch") ))) Produces the file `my-batch': #!/bin/sh # "my-batch" build script created Sat Jun 10 21:20:37 1995 # ================ Write file with C program. mv -f hello.c hello.c~ rm -f hello.c echo '#include <stdio.h>'>>hello.c echo 'int main(int argc, char **argv)'>>hello.c echo '{'>>hello.c echo ' printf("hello world\n");'>>hello.c echo ' return 0;'>>hello.c echo '}'>>hello.c cc -c hello.c cc -o hello hello.o hello rm -f hello rm -f hello.c rm -f hello.o rm -f my-batch When run, `my-batch' prints: bash$ my-batch mv: hello.c: No such file or directory hello world File: slib.info, Node: HTML HTTP and CGI, Next: Printing Scheme, Prev: Programs and Arguments, Up: Textual Conversion Packages HTML Forms ========== `(require 'html-form)' - Variable: *html:output-port* Procedure names starting with `html:' send their output to the port *HTML:OUTPUT-PORT*. *HTML:OUTPUT-PORT* is initially the current output port. - Function: make-atval TXT | Returns a string with character substitutions appropriate to send TXT as an "attribute-value". - Function: make-plain TXT | Returns a string with character substitutions appropriate to send TXT as an "plain-text". - Function: html:start-page TITLE BACKLINK TAGS ... | - Function: html:start-page TITLE BACKLINK | - Function: html:start-page TITLE | Outputs headers for an HTML page named TITLE. If string arguments | BACKLINK ... are supplied they are printed verbatim within the | <HEAD> section. | | - Function: html:end-page | Outputs HTML codes to end a page. | | - Function: html:pre LINE1 LINE ... | Writes (using `html:printf') the strings LINE1, LINES as | "PRE"formmated plain text (rendered in fixed-width font). | Newlines are inserted between LINE1, LINES. HTML tags (`<tag>') | within LINES will be visible verbatim. | | - Function: html:comment LINE1 LINE ... | Writes (using `html:printf') the strings LINE1 as HTML comments. | | HTML Tables | =========== | | - Function: html:start-table CAPTION | | - Function: html:end-table | | - Function: html:heading COLUMNS | Outputs a heading row for the currently-started table. | | - Function: html:href-heading COLUMNS URLS | Outputs a heading row with column-names COLUMNS linked to URLs | URLS. | | - Function: make-row-converter K FOREIGNS | The positive integer K is the primary-key-limit (number of | primary-keys) of the table. FOREIGNS is a list of the filenames of | foreign-key field pages and #f for non foreign-key fields. | | `make-row-converter' returns a procedure taking a row for its | single argument. This returned procedure prints the table row to | *HTML:OUTPUT-PORT*. | | - Function: table-name->filename TABLE-NAME | Returns the symbol TABLE-NAME converted to a filename. | | - Function: table->html CAPTION DB TABLE-NAME MATCH-KEY1 ... | Writes HTML for DB table TABLE-NAME to *HTML:OUTPUT-PORT*. | | The optional MATCH-KEY1 ... arguments restrict actions to a subset | of the table. *Note match-key: Table Operations. | | - Function: table->page DB TABLE-NAME INDEX-FILENAME | Writes a complete HTML page to *HTML:OUTPUT-PORT*. The string | INDEX-FILENAME names the page which refers to this one. | | - Function: catalog->html DB CAPTION | Writes HTML for the catalog table of DB to *HTML:OUTPUT-PORT*. | | - Function: catalog->page DB CAPTION | Writes a complete HTML page for the catalog of DB to | *HTML:OUTPUT-PORT*. | | HTML Forms | ========== | - Function: html:start-form METHOD ACTION The symbol METHOD is either `get', `head', `post', `put', or `delete'. `html:start-form' prints the header for an HTML "form". - Function: html:end-form PNAME SUBMIT-LABEL `html:end-form' prints the footer for an HTML "form". The string SUBMIT-LABEL appears on the button which submits the form. | - Function: command->html RDB COMMAND-TABLE COMMAND METHOD ACTION The symbol COMMAND-TABLE names a command table in the RDB relational database. `command->html' writes an HTML-2.0 "form" for command COMMAND to the current-output-port. The `SUBMIT' button, which is labeled COMMAND, invokes the URI ACTION with method METHOD with a hidden attribute `*command*' bound to the command symbol submitted. An action may invoke a CGI script (`http://www.my-site.edu/cgi-bin/search.cgi') or HTTP daemon (`http://www.my-site.edu:8001'). This example demonstrates how to create a HTML-form for the `build' command. (require (in-vicinity (implementation-vicinity) "build.scm")) (call-with-output-file "buildscm.html" (lambda (port) (fluid-let ((*html:output-port* port)) (html:start-page 'commands) (command->html build '*commands* 'build 'post (or "/cgi-bin/build.cgi" "http://localhost:8081/buildscm")) html:end-page))) HTTP and CGI service ==================== `(require 'html-form)' - Function: cgi:serve-command RDB COMMAND-TABLE Reads a `"POST"' or `"GET"' query from `(current-input-port)' and executes the encoded command from COMMAND-TABLE in relational-database RDB. This example puts up a plain-text page in response to a CGI query. (display "Content-Type: text/plain") (newline) (newline) (require 'html-form) (load (in-vicinity (implementation-vicinity) "build.scm")) (cgi:serve-command build '*commands*) - Function: serve-urlencoded-command RDB COMMAND-TABLE URLENCODED Reads attribute-value pairs from URLENCODED, converts them to parameters and invokes the RDB command named by the parameter `*command*'. - Function: http:serve-query INPUT-PORT OUTPUT-PORT SERVE-PROC reads the "query-string" from INPUT-PORT. If this is a valid `"POST"' or `"GET"' query, then `http:serve-query' calls SERVE-PROC with two arguments, the query-string and the header-alist. Otherwise, `http:serve-query' replies (to OUTPUT-PORT) with appropriate HTML describing the problem. This example services HTTP queries from port 8081: (define socket (make-stream-socket AF_INET 0)) (socket:bind socket 8081) (socket:listen socket 10) (dynamic-wind (lambda () #f) (lambda () (do ((port (socket:accept socket) (socket:accept socket))) (#f) (dynamic-wind (lambda () #f) (lambda () (fluid-let ((*html:output-port* port)) (http:serve-query port port (lambda (query-string header) (http:send-header '(("Content-Type" . "text/plain"))) (with-output-to-port port (lambda () (serve-urlencoded-command build '*commands* query-string))))))) (lambda () (close-port port))))) (lambda () (close-port socket))) - Function: http:read-request-line PORT Reads the first non-blank line from PORT and, if successful, returns a list of three itmes from the request-line: 0. Method Either one of the symbols `options', `get', `head', `post', `put', `delete', or `trace'; Or a string. 1. Request-URI A string. At the minimum, it will be the string `"/"'. 2. HTTP-Version A string. For example, `HTTP/1.0'. - Function: cgi:read-query-string Reads the "query-string" from `(current-input-port)'. `cgi:read-query-string' reads a `"POST"' or `"GET"' queries, depending on the value of `(getenv "REQUEST_METHOD")'. File: slib.info, Node: Printing Scheme, Next: Time and Date, Prev: HTML HTTP and CGI, Up: Textual Conversion Packages Printing Scheme =============== * Menu: * Generic-Write:: 'generic-write * Object-To-String:: 'object->string * Pretty-Print:: 'pretty-print, 'pprint-file File: slib.info, Node: Generic-Write, Next: Object-To-String, Prev: Printing Scheme, Up: Printing Scheme Generic-Write ------------- `(require 'generic-write)' `generic-write' is a procedure that transforms a Scheme data value (or Scheme program expression) into its textual representation and prints it. The interface to the procedure is sufficiently general to easily implement other useful formatting procedures such as pretty printing, output to a string and truncated output. - Procedure: generic-write OBJ DISPLAY? WIDTH OUTPUT OBJ Scheme data value to transform. DISPLAY? Boolean, controls whether characters and strings are quoted. WIDTH Extended boolean, selects format: #f single line format integer > 0 pretty-print (value = max nb of chars per line) OUTPUT Procedure of 1 argument of string type, called repeatedly with successive substrings of the textual representation. This procedure can return `#f' to stop the transformation. The value returned by `generic-write' is undefined. Examples: (write obj) == (generic-write obj #f #f DISPLAY-STRING) (display obj) == (generic-write obj #t #f DISPLAY-STRING) where DISPLAY-STRING == (lambda (s) (for-each write-char (string->list s)) #t) File: slib.info, Node: Object-To-String, Next: Pretty-Print, Prev: Generic-Write, Up: Printing Scheme Object-To-String ---------------- `(require 'object->string)' - Function: object->string OBJ Returns the textual representation of OBJ as a string. - Function: object->limited-string OBJ LIMIT Returns the textual representation of OBJ as a string of length at most LIMIT. File: slib.info, Node: Pretty-Print, Prev: Object-To-String, Up: Printing Scheme Pretty-Print ------------ `(require 'pretty-print)' - Procedure: pretty-print OBJ - Procedure: pretty-print OBJ PORT `pretty-print's OBJ on PORT. If PORT is not specified, `current-output-port' is used. Example: (pretty-print '((1 2 3 4 5) (6 7 8 9 10) (11 12 13 14 15) (16 17 18 19 20) (21 22 23 24 25))) -| ((1 2 3 4 5) -| (6 7 8 9 10) -| (11 12 13 14 15) -| (16 17 18 19 20) -| (21 22 23 24 25)) `(require 'pprint-file)' - Procedure: pprint-file INFILE - Procedure: pprint-file INFILE OUTFILE Pretty-prints all the code in INFILE. If OUTFILE is specified, the output goes to OUTFILE, otherwise it goes to `(current-output-port)'. - Function: pprint-filter-file INFILE PROC OUTFILE - Function: pprint-filter-file INFILE PROC INFILE is a port or a string naming an existing file. Scheme source code expressions and definitions are read from the port (or file) and PROC is applied to them sequentially. OUTFILE is a port or a string. If no OUTFILE is specified then `current-output-port' is assumed. These expanded expressions are then `pretty-print'ed to this port. Whitepsace and comments (introduced by `;') which are not part of scheme expressions are reproduced in the output. This procedure does not affect the values returned by `current-input-port' and `current-output-port'. `pprint-filter-file' can be used to pre-compile macro-expansion and thus can reduce loading time. The following will write into `exp-code.scm' the result of expanding all defmacros in `code.scm'. (require 'pprint-file) (require 'defmacroexpand) (defmacro:load "my-macros.scm") (pprint-filter-file "code.scm" defmacro:expand* "exp-code.scm") File: slib.info, Node: Time and Date, Next: Vector Graphics, Prev: Printing Scheme, Up: Textual Conversion Packages Time and Date ============= * Menu: * Time Zone:: | * Posix Time:: 'posix-time * Common-Lisp Time:: 'common-lisp-time If `(provided? 'current-time)': | | The procedures `current-time', `difftime', and `offset-time' deal with | a "calendar time" datatype which may or may not be disjoint from other | Scheme datatypes. | | - Function: current-time | Returns the time since 00:00:00 GMT, January 1, 1970, measured in | seconds. Note that the reference time is different from the | reference time for `get-universal-time' in *Note Common-Lisp Time::. | | - Function: difftime CALTIME1 CALTIME0 | Returns the difference (number of seconds) between twe calendar | times: CALTIME1 - CALTIME0. CALTIME0 may also be a number. | | - Function: offset-time CALTIME OFFSET | Returns the calendar time of CALTIME offset by OFFSET number of | seconds `(+ caltime offset)'. | | File: slib.info, Node: Time Zone, Next: Posix Time, Prev: Time and Date, Up: Time and Date | Time Zone | --------- | | (require 'time-zone) | | - Data Format: TZ-string | POSIX standards specify several formats for encoding time-zone | rules. | | :<pathname> | If the first character of <pathname> is `/', then <pathname> | specifies the absolute pathname of a tzfile(5) format | time-zone file. Otherwise, <pathname> is interpreted as a | pathname within TZFILE:VICINITY (/usr/lib/zoneinfo/) naming a | tzfile(5) format time-zone file. | | <std><offset> | The string <std> consists of 3 or more alphabetic characters. | <offset> specifies the time difference from GMT. The <offset> | is positive if the local time zone is west of the Prime | Meridian and negative if it is east. <offset> can be the | number of hours or hours and minutes (and optionally seconds) | separated by `:'. For example, `-4:30'. | | <std><offset><dst> | <dst> is the at least 3 alphabetic characters naming the local | daylight-savings-time. | | <std><offset><dst><doffset> | <doffset> specifies the offset from the Prime Meridian when | daylight-savings-time is in effect. | | The non-tzfile formats can optionally be followed by transition | times specifying the day and time when a zone changes from | standard to daylight-savings and back again. | | ,<date>/<time>,<date>/<time> | The <time>s are specified like the <offset>s above, except | that leading `+' and `-' are not allowed. | | Each <date> has one of the formats: | | J<day> | specifies the Julian day with <day> between 1 and 365. | February 29 is never counted and cannot be referenced. | | <day> | This specifies the Julian day with n between 0 and 365. | February 29 is counted in leap years and can be | specified. | | M<month>.<week>.<day> | This specifies day <day> (0 <= <day> <= 6) of week | <week> (1 <= <week> <= 5) of month <month> (1 <= <month> | <= 12). Week 1 is the first week in which day d occurs | and week 5 is the last week in which day <day> occurs. | Day 0 is a Sunday. | | | - Data Type: time-zone | is a datatype encoding how many hours from Greenwich Mean Time the | local time is, and the "Daylight Savings Time" rules for changing | it. | | - Function: time-zone TZ-STRING | Creates and returns a time-zone object specified by the string | TZ-STRING. If `time-zone' cannot interpret TZ-STRING, `#f' is | returned. | | - Function: tz:params CALTIME TZ | TZ is a time-zone object. `tz:params' returns a list of three | items: | 0. An integer. 0 if standard time is in effect for timezone TZ | at CALTIME; 1 if daylight savings time is in effect for | timezone TZ at CALTIME. | | 1. The number of seconds west of the Prime Meridian timezone TZ | is at CALTIME. | | 2. The name for timezone TZ at CALTIME. | | `tz:params' is unaffected by the default timezone; inquiries can be | made of any timezone at any calendar time. | | | The rest of these procedures and variables are provided for POSIX | compatability. Because of shared state they are not thread-safe. | | - Function: tzset | Returns the default time-zone. | | - Function: tzset TZ | Sets (and returns) the default time-zone to TZ. | | - Function: tzset TZ-STRING | Sets (and returns) the default time-zone to that specified by | TZ-STRING. | | `tzset' also sets the variables *TIMEZONE*, DAYLIGHT?, and TZNAME. | This function is automatically called by the time conversion | procedures which depend on the time zone (*note Time and Date::.). | | - Variable: *timezone* | Contains the difference, in seconds, between Greenwich Mean Time | and local standard time (for example, in the U.S. Eastern time | zone (EST), timezone is 5*60*60). `*timezone*' is initialized by | `tzset'. | | - Variable: daylight? | is `#t' if the default timezone has rules for "Daylight Savings | Time". *Note:* DAYLIGHT? does not tell you when Daylight Savings | Time is in effect, just that the default zone sometimes has | Daylight Savings Time. | | - Variable: tzname | is a vector of strings. Index 0 has the abbreviation for the | standard timezone; If DAYLIGHT?, then index 1 has the abbreviation | for the Daylight Savings timezone. | | File: slib.info, Node: Posix Time, Next: Common-Lisp Time, Prev: Time Zone, Up: Time and Date | Posix Time ---------- (require 'posix-time) - Data Type: Calendar-Time is a datatype encapsulating time. - Data Type: Coordinated Universal Time (abbreviated "UTC") is a vector of integers representing time: 0. seconds (0 - 61) 1. minutes (0 - 59) 2. hours since midnight (0 - 23) 3. day of month (1 - 31) 4. month (0 - 11). Note difference from `decode-universal-time'. 5. the number of years since 1900. Note difference from `decode-universal-time'. 6. day of week (0 - 6) 7. day of year (0 - 365) 8. 1 for daylight savings, 0 for regular time - Function: gmtime CALTIME Converts the calendar time CALTIME to UTC and returns it. - Function: localtime CALTIME TZ Returns CALTIME converted to UTC relative to timezone TZ. - Function: localtime CALTIME converts the calendar time CALTIME to a vector of integers expressed relative to the user's time zone. `localtime' sets the variable *TIMEZONE* with the difference between Coordinated Universal Time (UTC) and local standard time in seconds (*note tzset: Time Zone.). - Function: gmktime UNIVTIME Converts a vector of integers in GMT Coordinated Universal Time (UTC) format to a calendar time. - Function: mktime UNIVTIME Converts a vector of integers in local Coordinated Universal Time (UTC) format to a calendar time. - Function: mktime UNIVTIME TZ Converts a vector of integers in Coordinated Universal Time (UTC) format (relative to time-zone TZ) to calendar time. - Function: asctime UNIVTIME Converts the vector of integers CALTIME in Coordinated Universal Time (UTC) format into a string of the form `"Wed Jun 30 21:49:08 1993"'. - Function: gtime CALTIME - Function: ctime CALTIME - Function: ctime CALTIME TZ Equivalent to `(asctime (gmtime CALTIME))', `(asctime (localtime CALTIME))', and `(asctime (localtime CALTIME TZ))', respectively. File: slib.info, Node: Common-Lisp Time, Prev: Posix Time, Up: Time and Date Common-Lisp Time ---------------- - Function: get-decoded-time Equivalent to `(decode-universal-time (get-universal-time))'. - Function: get-universal-time Returns the current time as "Universal Time", number of seconds since 00:00:00 Jan 1, 1900 GMT. Note that the reference time is different from `current-time'. - Function: decode-universal-time UNIVTIME Converts UNIVTIME to "Decoded Time" format. Nine values are returned: 0. seconds (0 - 61) 1. minutes (0 - 59) 2. hours since midnight 3. day of month 4. month (1 - 12). Note difference from `gmtime' and `localtime'. 5. year (A.D.). Note difference from `gmtime' and `localtime'. 6. day of week (0 - 6) 7. #t for daylight savings, #f otherwise 8. hours west of GMT (-24 - +24) Notice that the values returned by `decode-universal-time' do not match the arguments to `encode-universal-time'. - Function: encode-universal-time SECOND MINUTE HOUR DATE MONTH YEAR - Function: encode-universal-time SECOND MINUTE HOUR DATE MONTH YEAR TIME-ZONE Converts the arguments in Decoded Time format to Universal Time format. If TIME-ZONE is not specified, the returned time is adjusted for daylight saving time. Otherwise, no adjustment is performed. Notice that the values returned by `decode-universal-time' do not match the arguments to `encode-universal-time'. File: slib.info, Node: Vector Graphics, Next: Schmooz, Prev: Time and Date, Up: Textual Conversion Packages Vector Graphics =============== * Menu: * Tektronix Graphics Support:: File: slib.info, Node: Tektronix Graphics Support, Prev: Vector Graphics, Up: Vector Graphics Tektronix Graphics Support -------------------------- *Note:* The Tektronix graphics support files need more work, and are not complete. Tektronix 4000 Series Graphics .............................. The Tektronix 4000 series graphics protocol gives the user a 1024 by 1024 square drawing area. The origin is in the lower left corner of the screen. Increasing y is up and increasing x is to the right. The graphics control codes are sent over the current-output-port and can be mixed with regular text and ANSI or other terminal control sequences. - Procedure: tek40:init - Procedure: tek40:graphics - Procedure: tek40:text - Procedure: tek40:linetype LINETYPE - Procedure: tek40:move X Y - Procedure: tek40:draw X Y - Procedure: tek40:put-text X Y STR - Procedure: tek40:reset Tektronix 4100 Series Graphics .............................. The graphics control codes are sent over the current-output-port and can be mixed with regular text and ANSI or other terminal control sequences. - Procedure: tek41:init - Procedure: tek41:reset - Procedure: tek41:graphics - Procedure: tek41:move X Y - Procedure: tek41:draw X Y - Procedure: tek41:point X Y NUMBER - Procedure: tek41:encode-x-y X Y - Procedure: tek41:encode-int NUMBER File: slib.info, Node: Schmooz, Prev: Vector Graphics, Up: Textual Conversion Packages Schmooz ======= "Schmooz" is a simple, lightweight markup language for interspersing Texinfo documentation with Scheme source code. Schmooz does not create the top level Texinfo file; it creates `txi' files which can be imported into the documentation using the Texinfo command `@include'. `(require 'schmooz)' defines the function `schmooz', which is used to process files. Files containing schmooz documentation should not contain `(require 'schmooz)'. - Procedure: schmooz FILENAMEscm ... FILENAMEscm should be a string ending with `scm' naming an existing file containing Scheme source code. `schmooz' extracts top-level comments containing schmooz commands from FILENAMEscm and writes the converted Texinfo source to a file named FILENAMEtxi. - Procedure: schmooz FILENAMEtexi ... - Procedure: schmooz FILENAMEtex ... - Procedure: schmooz FILENAMEtxi ... FILENAME should be a string naming an existing file containing Texinfo source code. For every occurrence of the string `@include FILENAMEtxi' within that file, `schmooz' calls itself with the argument `FILENAMEscm'. Schmooz comments are distinguished (from non-schmooz comments) by their first line, which must start with an at-sign (@) preceded by one or more semicolons (;). A schmooz comment ends at the first subsequent line which does *not* start with a semicolon. Currently schmooz comments are recognized only at top level. Schmooz comments are copied to the Texinfo output file with the leading contiguous semicolons removed. Certain character sequences starting with at-sign are treated specially. Others are copied unchanged. A schmooz comment starting with `@body' must be followed by a Scheme definition. All comments between the `@body' line and the definition will be included in a Texinfo definition, either a `@defun' or a `@defvar', depending on whether a procedure or a variable is being defined. Within the text of that schmooz comment, at-sign followed by `0' will be replaced by `@code{procedure-name}' if the following definition is of a procedure; or `@var{variable}' if defining a variable. An at-sign followed by a non-zero digit will expand to the variable citation of that numbered argument: `@var{argument-name}'. If more than one definition follows a `@body' comment line without an intervening blank or comment line, then those definitions will be included in the same Texinfo definition using `@defvarx' or `@defunx', depending on whether the first definition is of a variable or of a procedure. Schmooz can figure out whether a definition is of a procedure if it is of the form: `(define (<identifier> <arg> ...) <expression>)' or if the left hand side of the definition is some form ending in a lambda expression. Obviously, it can be fooled. In order to force recognition of a procedure definition, start the documentation with `@args' instead of `@body'. `@args' should be followed by the argument list of the function being defined, which may be enclosed in parentheses and delimited by whitespace, (as in Scheme), enclosed in braces and separated by commas, (as in Texinfo), or consist of the remainder of the line, separated by whitespace. For example: ;;@args arg1 args ... ;;@0 takes argument @1 and any number of @2 (define myfun (some-function-returning-magic)) Will result in: @defun myfun arg1 args @dots{} @code{myfun} takes argument @var{arg1} and any number of @var{args} @end defun `@args' may also be useful for indicating optional arguments by name. If `@args' occurs inside a schmooz comment section, rather than at the beginning, then it will generate a `@defunx' line with the arguments supplied. If the first at-sign in a schmooz comment is immediately followed by whitespace, then the comment will be expanded to whatever follows that whitespace. If the at-sign is followed by a non-whitespace character then the at-sign will be included as the first character of the expansion. This feature is intended to make it easy to include Texinfo directives in schmooz comments. File: slib.info, Node: Mathematical Packages, Next: Database Packages, Prev: Textual Conversion Packages, Up: Top Mathematical Packages ********************* * Menu: * Bit-Twiddling:: 'logical * Modular Arithmetic:: 'modular * Prime Numbers:: 'factor * Random Numbers:: 'random * Cyclic Checksum:: 'make-crc * Plotting:: 'charplot * Root Finding:: 'root * Commutative Rings:: 'commutative-ring * Determinant:: 'determinant File: slib.info, Node: Bit-Twiddling, Next: Modular Arithmetic, Prev: Mathematical Packages, Up: Mathematical Packages Bit-Twiddling ============= `(require 'logical)' The bit-twiddling functions are made available through the use of the `logical' package. `logical' is loaded by inserting `(require 'logical)' before the code that uses these functions. These functions behave as though operating on integers in two's-complement representation. Bitwise Operations ------------------ - Function: logand N1 N1 Returns the integer which is the bit-wise AND of the two integer arguments. Example: (number->string (logand #b1100 #b1010) 2) => "1000" - Function: logior N1 N2 Returns the integer which is the bit-wise OR of the two integer arguments. Example: (number->string (logior #b1100 #b1010) 2) => "1110" - Function: logxor N1 N2 Returns the integer which is the bit-wise XOR of the two integer arguments. Example: (number->string (logxor #b1100 #b1010) 2) => "110" - Function: lognot N Returns the integer which is the 2s-complement of the integer argument. Example: (number->string (lognot #b10000000) 2) => "-10000001" (number->string (lognot #b0) 2) => "-1" - Function: bitwise-if MASK N0 N1 Returns an integer composed of some bits from integer N0 and some from integer N1. A bit of the result is taken from N0 if the corresponding bit of integer MASK is 1 and from N1 if that bit of MASK is 0. - Function: logtest J K (logtest j k) == (not (zero? (logand j k))) (logtest #b0100 #b1011) => #f (logtest #b0100 #b0111) => #t - Function: logcount N Returns the number of bits in integer N. If integer is positive, the 1-bits in its binary representation are counted. If negative, the 0-bits in its two's-complement binary representation are counted. If 0, 0 is returned. Example: (logcount #b10101010) => 4 (logcount 0) => 0 (logcount -2) => 1 Bit Within Word --------------- - Function: logbit? INDEX J (logbit? index j) == (logtest (integer-expt 2 index) j) (logbit? 0 #b1101) => #t (logbit? 1 #b1101) => #f (logbit? 2 #b1101) => #t (logbit? 3 #b1101) => #t (logbit? 4 #b1101) => #f - Function: copy-bit INDEX FROM BIT Returns an integer the same as FROM except in the INDEXth bit, which is 1 if BIT is `#t' and 0 if BIT is `#f'. Example: (number->string (copy-bit 0 0 #t) 2) => "1" (number->string (copy-bit 2 0 #t) 2) => "100" (number->string (copy-bit 2 #b1111 #f) 2) => "1011" Fields of Bits -------------- - Function: bit-field N START END Returns the integer composed of the START (inclusive) through END (exclusive) bits of N. The STARTth bit becomes the 0-th bit in the result. This function was called `bit-extract' in previous versions of SLIB. Example: (number->string (bit-field #b1101101010 0 4) 2) => "1010" (number->string (bit-field #b1101101010 4 9) 2) => "10110" - Function: copy-bit-field TO START END FROM Returns an integer the same as TO except possibly in the START (inclusive) through END (exclusive) bits, which are the same as those of FROM. The 0-th bit of FROM becomes the STARTth bit of the result. Example: (number->string (copy-bit-field #b1101101010 0 4 0) 2) => "1101100000" (number->string (copy-bit-field #b1101101010 0 4 -1) 2) => "1101101111" - Function: ash INT COUNT Returns an integer equivalent to `(inexact->exact (floor (* INT (expt 2 COUNT))))'. Example: (number->string (ash #b1 3) 2) => "1000" (number->string (ash #b1010 -1) 2) => "101" - Function: integer-length N Returns the number of bits neccessary to represent N. Example: (integer-length #b10101010) => 8 (integer-length 0) => 0 (integer-length #b1111) => 4 - Function: integer-expt N K Returns N raised to the non-negative integer exponent K. Example: (integer-expt 2 5) => 32 (integer-expt -3 3) => -27 File: slib.info, Node: Modular Arithmetic, Next: Prime Numbers, Prev: Bit-Twiddling, Up: Mathematical Packages Modular Arithmetic ================== `(require 'modular)' - Function: extended-euclid N1 N2 Returns a list of 3 integers `(d x y)' such that d = gcd(N1, N2) = N1 * x + N2 * y. - Function: symmetric:modulus N Returns `(quotient (+ -1 n) -2)' for positive odd integer N. - Function: modulus->integer MODULUS Returns the non-negative integer characteristic of the ring formed when MODULUS is used with `modular:' procedures. - Function: modular:normalize MODULUS N Returns the integer `(modulo N (modulus->integer MODULUS))' in the representation specified by MODULUS. The rest of these functions assume normalized arguments; That is, the arguments are constrained by the following table: For all of these functions, if the first argument (MODULUS) is: `positive?' Work as before. The result is between 0 and MODULUS. `zero?' The arguments are treated as integers. An integer is returned. `negative?' The arguments and result are treated as members of the integers modulo `(+ 1 (* -2 MODULUS))', but with "symmetric" representation; i.e. `(<= (- MODULUS) N MODULUS)'. If all the arguments are fixnums the computation will use only fixnums. - Function: modular:invertable? MODULUS K Returns `#t' if there exists an integer n such that K * n == 1 mod MODULUS, and `#f' otherwise. - Function: modular:invert MODULUS K2 Returns an integer n such that 1 = (n * K2) mod MODULUS. If K2 has no inverse mod MODULUS an error is signaled. - Function: modular:negate MODULUS K2 Returns (-K2) mod MODULUS. - Function: modular:+ MODULUS K2 K3 Returns (K2 + K3) mod MODULUS. - Function: modular:- MODULUS K2 K3 Returns (K2 - K3) mod MODULUS. - Function: modular:* MODULUS K2 K3 Returns (K2 * K3) mod MODULUS. The Scheme code for `modular:*' with negative MODULUS is not completed for fixnum-only implementations. - Function: modular:expt MODULUS K2 K3 Returns (K2 ^ K3) mod MODULUS. File: slib.info, Node: Prime Numbers, Next: Random Numbers, Prev: Modular Arithmetic, Up: Mathematical Packages Prime Numbers ============= `(require 'factor)' - Variable: prime:prngs PRIME:PRNGS is the random-state (*note Random Numbers::.) used by these procedures. If you call these procedures from more than one thread (or from interrupt), `random' may complain about reentrant calls. - Function: jacobi-symbol P Q Returns the value (+1, -1, or 0) of the Jacobi-Symbol of exact non-negative integer P and exact positive odd integer Q. - Variable: prime:trials PRIME:TRIALS the maxinum number of iterations of Solovay-Strassen that will be done to test a number for primality. - Function: prime? N Returns `#f' if N is composite; `#t' if N is prime. There is a slight chance `(expt 2 (- prime:trials))' that a composite will return `#t'. - Function: primes< START COUNT Returns a list of the first COUNT prime numbers less than START. If there are fewer than COUNT prime numbers less than START, then the returned list will have fewer than START elements. - Function: primes> START COUNT Returns a list of the first COUNT prime numbers greater than START. - Function: factor K Returns a list of the prime factors of K. The order of the factors is unspecified. In order to obtain a sorted list do `(sort! (factor K) <)'. File: slib.info, Node: Random Numbers, Next: Cyclic Checksum, Prev: Prime Numbers, Up: Mathematical Packages Random Numbers ============== `(require 'random)' A pseudo-random number generator is only as good as the tests it passes. George Marsaglia of Florida State University developed a battery of tests named "DIEHARD" (`http://stat.fsu.edu/~geo/diehard.html'). `diehard.c' has a bug which the patch `ftp://swissnet.ai.mit.edu/pub/users/jaffer/diehard.c.pat' corrects. SLIB's new PRNG generates 8 bits at a time. With the degenerate seed `0', the numbers generated pass DIEHARD; but when bits are combined from sequential bytes, tests fail. With the seed `http://swissnet.ai.mit.edu/~jaffer/SLIB.html', all of those tests pass. - Function: random N | - Function: random N STATE | Accepts a positive integer or real N and returns a number of the same type between zero (inclusive) and N (exclusive). The values returned by `random' are uniformly distributed from 0 to N. | The optional argument STATE must be of the type returned by | `(seed->random-state)' or `(make-random-state)'. It defaults to | the value of the variable `*random-state*'. This object is used | to maintain the state of the pseudo-random-number generator and is | altered as a side effect of calls to `random'. | - Variable: *random-state* Holds a data structure that encodes the internal state of the random-number generator that `random' uses by default. The nature of this data structure is implementation-dependent. It may be printed out and successfully read back in, but may or may not function correctly as a random-number state object in another implementation. - Function: copy-random-state STATE | Returns a new copy of argument STATE. | | - Function: copy-random-state | Returns a new copy of `*random-state*'. | | - Function: seed->random-state SEED | Returns a new object of type suitable for use as the value of the | variable `*random-state*' or as a second argument to `random'. | The number or string SEED is used to initialize the state. If | `seed->random-state' is called twice with arguments which are | `equal?', then the returned data structures will be `equal?'. | Calling `seed->random-state' with unequal arguments will nearly | always return unequal states. | | - Function: make-random-state | - Function: make-random-state OBJ | Returns a new object of type suitable for use as the value of the variable `*random-state*' or as a second argument to `random'. If | the optional argument OBJ is given, it should be a printable | Scheme object; the first 50 characters of its printed | representation will be used as the seed. Otherwise the value of | `*random-state*' is used as the seed. | If inexact numbers are supported by the Scheme implementation, `randinex.scm' will be loaded as well. `randinex.scm' contains procedures for generating inexact distributions. - Function: random:uniform | - Function: random:uniform STATE | Returns an uniformly distributed inexact real random number in the range between 0 and 1. - Function: random:exp | - Function: random:exp STATE | Returns an inexact real in an exponential distribution with mean | 1. For an exponential distribution with mean U use | `(* U (random:exp))'. | | - Function: random:normal | - Function: random:normal STATE | Returns an inexact real in a normal distribution with mean 0 and | standard deviation 1. For a normal distribution with mean M and | standard deviation D use `(+ M (* D (random:normal)))'. | | - Function: random:normal-vector! VECT | - Function: random:normal-vector! VECT STATE | Fills VECT with inexact real random numbers which are independent | and standard normally distributed (i.e., with mean 0 and variance | 1). | | - Function: random:hollow-sphere! VECT | - Function: random:hollow-sphere! VECT STATE | Fills VECT with inexact real random numbers the sum of whose squares is less than 1.0. Thinking of VECT as coordinates in space of dimension N = `(vector-length VECT)', the coordinates are uniformly distributed within the unit N-shere. The sum of the squares of the numbers is returned. - Function: random:solid-sphere! VECT | - Function: random:solid-sphere! VECT STATE | Fills VECT with inexact real random numbers the sum of whose squares is equal to 1.0. Thinking of VECT as coordinates in space of dimension n = `(vector-length VECT)', the coordinates are uniformly distributed over the surface of the unit n-shere. | File: slib.info, Node: Cyclic Checksum, Next: Plotting, Prev: Random Numbers, Up: Mathematical Packages Cyclic Checksum =============== `(require 'make-crc)' - Function: make-port-crc - Function: make-port-crc DEGREE - Function: make-port-crc DEGREE GENERATOR Returns an expression for a procedure of one argument, a port. This procedure reads characters from the port until the end of file and returns the integer checksum of the bytes read. The integer DEGREE, if given, specifies the degree of the polynomial being computed - which is also the number of bits computed in the checksums. The default value is 32. The integer GENERATOR specifies the polynomial being computed. The power of 2 generating each 1 bit is the exponent of a term of the polynomial. The bit at position DEGREE is implicit and should not be part of GENERATOR. This allows systems with numbers limited to 32 bits to calculate 32 bit checksums. The default value of GENERATOR when DEGREE is 32 (its default) is: (make-port-crc 32 #b00000100110000010001110110110111) Creates a procedure to calculate the P1003.2/D11.2 (POSIX.2) 32-bit checksum from the polynomial: 32 26 23 22 16 12 11 ( x + x + x + x + x + x + x + 10 8 7 5 4 2 1 x + x + x + x + x + x + x + 1 ) mod 2 (require 'make-crc) (define crc32 (slib:eval (make-port-crc))) (define (file-check-sum file) (call-with-input-file file crc32)) (file-check-sum (in-vicinity (library-vicinity) "ratize.scm")) => 3553047446 File: slib.info, Node: Plotting, Next: Root Finding, Prev: Cyclic Checksum, Up: Mathematical Packages Plotting on Character Devices ============================= `(require 'charplot)' The plotting procedure is made available through the use of the `charplot' package. `charplot' is loaded by inserting `(require 'charplot)' before the code that uses this procedure. - Variable: charplot:height The number of rows to make the plot vertically. - Variable: charplot:width The number of columns to make the plot horizontally. - Procedure: plot! COORDS X-LABEL Y-LABEL COORDS is a list of pairs of x and y coordinates. X-LABEL and Y-LABEL are strings with which to label the x and y axes. Example: (require 'charplot) (set! charplot:height 19) (set! charplot:width 45) (define (make-points n) (if (zero? n) '() (cons (cons (/ n 6) (sin (/ n 6))) (make-points (1- n))))) (plot! (make-points 37) "x" "Sin(x)") -| Sin(x) ______________________________________________ 1.25|- | | | 1|- **** | | ** ** | 750.0e-3|- * * | | * * | 500.0e-3|- * * | | * | 250.0e-3|- * | | * * | 0|-------------------*--------------------------| | * | -250.0e-3|- * * | | * * | -500.0e-3|- * | | * * | -750.0e-3|- * * | | ** ** | -1|- **** | |____________:_____._____:_____._____:_________| x 2 4 File: slib.info, Node: Root Finding, Next: Commutative Rings, Prev: Plotting, Up: Mathematical Packages Root Finding ============ `(require 'root)' - Function: newtown:find-integer-root F DF/DX X0 Given integer valued procedure F, its derivative (with respect to its argument) DF/DX, and initial integer value X0 for which DF/DX(X0) is non-zero, returns an integer X for which F(X) is closer to zero than either of the integers adjacent to X; or returns `#f' if such an integer can't be found. To find the closest integer to a given integers square root: (define (integer-sqrt y) (newton:find-integer-root (lambda (x) (- (* x x) y)) (lambda (x) (* 2 x)) (ash 1 (quotient (integer-length y) 2)))) (integer-sqrt 15) => 4 - Function: integer-sqrt Y Given a non-negative integer Y, returns the rounded square-root of Y. - Function: newton:find-root F DF/DX X0 PREC Given real valued procedures F, DF/DX of one (real) argument, initial real value X0 for which DF/DX(X0) is non-zero, and positive real number PREC, returns a real X for which `abs'(F(X)) is less than PREC; or returns `#f' if such a real can't be found. If PREC is instead a negative integer, `newton:find-root' returns | the result of -PREC iterations. | H. J. Orchard, `The Laguerre Method for Finding the Zeros of Polynomials', IEEE Transactions on Circuits and Systems, Vol. 36, No. 11, November 1989, pp 1377-1381. There are 2 errors in Orchard's Table II. Line k=2 for starting value of 1000+j0 should have Z_k of 1.0475 + j4.1036 and line k=2 for starting value of 0+j1000 should have Z_k of 1.0988 + j4.0833. - Function: laguerre:find-root F DF/DZ DDF/DZ^2 Z0 PREC Given complex valued procedure F of one (complex) argument, its derivative (with respect to its argument) DF/DX, its second derivative DDF/DZ^2, initial complex value Z0, and positive real number PREC, returns a complex number Z for which `magnitude'(F(Z)) is less than PREC; or returns `#f' if such a number can't be found. If PREC is instead a negative integer, `laguerre:find-root' | returns the result of -PREC iterations. - Function: laguerre:find-polynomial-root DEG F DF/DZ DDF/DZ^2 Z0 PREC Given polynomial procedure F of integer degree DEG of one argument, its derivative (with respect to its argument) DF/DX, its second derivative DDF/DZ^2, initial complex value Z0, and positive real number PREC, returns a complex number Z for which `magnitude'(F(Z)) is less than PREC; or returns `#f' if such a number can't be found. If PREC is instead a negative integer, | `laguerre:find-polynomial-root' returns the result of -PREC iterations. - Function: secant:find-root F X0 X1 PREC | - Function: secant:find-bracketed-root F X0 X1 PREC | Given a real valued procedure F and two real valued starting | points X0 and X1, returns a real X for which `(abs (f x))' is less | than PREC; or returns `#f' if such a real can't be found. | | If X0 and X1 are chosen such that they bracket a root, that is | (or (< (f x0) 0 (f x1)) | (< (f x1) 0 (f x0))) | then the root returned will be between X0 and X1, and F will not | be passed an argument outside of that interval. | | `secant:find-bracketed-root' will return `#f' unless X0 and X1 | bracket a root. | | The secant or regula falsi method will be used unless a bracketing | interval has been found and the secant method is not making | sufficient progress, in which case bisection of the interval will | be used. | | If PREC is instead a negative integer, `secant:find-root' returns | the result of -PREC iterations. | | If PREC is a procedure it should accept 5 arguments: X0 F0 X1 F1 | and COUNT, where F0 will be `(f x0)', F1 `(f x1)', and COUNT the | number of iterations performed so far. PREC should return | non-false if the iteration should be stopped. | | File: slib.info, Node: Commutative Rings, Next: Determinant, Prev: Root Finding, Up: Mathematical Packages Commutative Rings ================= Scheme provides a consistent and capable set of numeric functions. Inexacts implement a field; integers a commutative ring (and Euclidean domain). This package allows one to use basic Scheme numeric functions with symbols and non-numeric elements of commutative rings. `(require 'commutative-ring)' The "commutative-ring" package makes the procedures `+', `-', `*', `/', and `^' "careful" in the sense that any non-numeric arguments they do not reduce appear in the expression output. In order to see what working with this package is like, self-set all the single letter identifiers (to their corresponding symbols). (define a 'a) ... (define z 'z) Or just `(require 'self-set)'. Now try some sample expressions: (+ (+ a b) (- a b)) => (* a 2) (* (+ a b) (+ a b)) => (^ (+ a b) 2) (* (+ a b) (- a b)) => (* (+ a b) (- a b)) (* (- a b) (- a b)) => (^ (- a b) 2) (* (- a b) (+ a b)) => (* (+ a b) (- a b)) (/ (+ a b) (+ c d)) => (/ (+ a b) (+ c d)) (^ (+ a b) 3) => (^ (+ a b) 3) (^ (+ a 2) 3) => (^ (+ 2 a) 3) Associative rules have been applied and repeated addition and multiplication converted to multiplication and exponentiation. We can enable distributive rules, thus expanding to sum of products form: (set! *ruleset* (combined-rulesets distribute* distribute/)) (* (+ a b) (+ a b)) => (+ (* 2 a b) (^ a 2) (^ b 2)) (* (+ a b) (- a b)) => (- (^ a 2) (^ b 2)) (* (- a b) (- a b)) => (- (+ (^ a 2) (^ b 2)) (* 2 a b)) (* (- a b) (+ a b)) => (- (^ a 2) (^ b 2)) (/ (+ a b) (+ c d)) => (+ (/ a (+ c d)) (/ b (+ c d))) (/ (+ a b) (- c d)) => (+ (/ a (- c d)) (/ b (- c d))) (/ (- a b) (- c d)) => (- (/ a (- c d)) (/ b (- c d))) (/ (- a b) (+ c d)) => (- (/ a (+ c d)) (/ b (+ c d))) (^ (+ a b) 3) => (+ (* 3 a (^ b 2)) (* 3 b (^ a 2)) (^ a 3) (^ b 3)) (^ (+ a 2) 3) => (+ 8 (* a 12) (* (^ a 2) 6) (^ a 3)) Use of this package is not restricted to simple arithmetic expressions: (require 'determinant) (determinant '((a b c) (d e f) (g h i))) => (- (+ (* a e i) (* b f g) (* c d h)) (* a f h) (* b d i) (* c e g)) Currently, only `+', `-', `*', `/', and `^' support non-numeric elements. Expressions with `-' are converted to equivalent expressions without `-', so behavior for `-' is not defined separately. `/' expressions are handled similarly. This list might be extended to include `quotient', `modulo', `remainder', `lcm', and `gcd'; but these work only for the more restrictive Euclidean (Unique Factorization) Domain. Rules and Rulesets ================== The "commutative-ring" package allows control of ring properties through the use of "rulesets". - Variable: *ruleset* Contains the set of rules currently in effect. Rules defined by `cring:define-rule' are stored within the value of *ruleset* at the time `cring:define-rule' is called. If *RULESET* is `#f', then no rules apply. - Function: make-ruleset RULE1 ... - Function: make-ruleset NAME RULE1 ... Returns a new ruleset containing the rules formed by applying `cring:define-rule' to each 4-element list argument RULE. If the first argument to `make-ruleset' is a symbol, then the database table created for the new ruleset will be named NAME. Calling `make-ruleset' with no rule arguments creates an empty ruleset. - Function: combined-rulesets RULESET1 ... - Function: combined-rulesets NAME RULESET1 ... Returns a new ruleset containing the rules contained in each ruleset argument RULESET. If the first argument to `combined-ruleset' is a symbol, then the database table created for the new ruleset will be named NAME. Calling `combined-ruleset' with no ruleset arguments creates an empty ruleset. Two rulesets are defined by this package. - Constant: distribute* Contain the ruleset to distribute multiplication over addition and subtraction. - Constant: distribute/ Contain the ruleset to distribute division over addition and subtraction. Take care when using both DISTRIBUTE* and DISTRIBUTE/ simultaneously. It is possible to put `/' into an infinite loop. You can specify how sum and product expressions containing non-numeric elements simplify by specifying the rules for `+' or `*' for cases where expressions involving objects reduce to numbers or to expressions involving different non-numeric elements. - Function: cring:define-rule OP SUB-OP1 SUB-OP2 REDUCTION Defines a rule for the case when the operation represented by symbol OP is applied to lists whose `car's are SUB-OP1 and SUB-OP2, respectively. The argument REDUCTION is a procedure accepting 2 arguments which will be lists whose `car's are SUB-OP1 and SUB-OP2. - Function: cring:define-rule OP SUB-OP1 'IDENTITY REDUCTION Defines a rule for the case when the operation represented by symbol OP is applied to a list whose `car' is SUB-OP1, and some other argument. REDUCTION will be called with the list whose `car' is SUB-OP1 and some other argument. If REDUCTION returns `#f', the reduction has failed and other reductions will be tried. If REDUCTION returns a non-false value, that value will replace the two arguments in arithmetic (`+', `-', and `*') calculations involving non-numeric elements. The operations `+' and `*' are assumed commutative; hence both orders of arguments to REDUCTION will be tried if necessary. The following rule is the definition for distributing `*' over `+'. (cring:define-rule '* '+ 'identity (lambda (exp1 exp2) (apply + (map (lambda (trm) (* trm exp2)) (cdr exp1)))))) How to Create a Commutative Ring ================================ The first step in creating your commutative ring is to write procedures to create elements of the ring. A non-numeric element of the ring must be represented as a list whose first element is a symbol or string. This first element identifies the type of the object. A convenient and clear convention is to make the type-identifying element be the same symbol whose top-level value is the procedure to create it. (define (n . list1) (cond ((and (= 2 (length list1)) (eq? (car list1) (cadr list1))) 0) ((not (term< (first list1) (last1 list1))) (apply n (reverse list1))) (else (cons 'n list1)))) (define (s x y) (n x y)) (define (m . list1) (cond ((neq? (first list1) (term_min list1)) (apply m (cyclicrotate list1))) ((term< (last1 list1) (cadr list1)) (apply m (reverse (cyclicrotate list1)))) (else (cons 'm list1)))) Define a procedure to multiply 2 non-numeric elements of the ring. Other multiplicatons are handled automatically. Objects for which rules have *not* been defined are not changed. (define (n*n ni nj) (let ((list1 (cdr ni)) (list2 (cdr nj))) (cond ((null? (intersection list1 list2)) #f) ((and (eq? (last1 list1) (first list2)) (neq? (first list1) (last1 list2))) (apply n (splice list1 list2))) ((and (eq? (first list1) (first list2)) (neq? (last1 list1) (last1 list2))) (apply n (splice (reverse list1) list2))) ((and (eq? (last1 list1) (last1 list2)) (neq? (first list1) (first list2))) (apply n (splice list1 (reverse list2)))) ((and (eq? (last1 list1) (first list2)) (eq? (first list1) (last1 list2))) (apply m (cyclicsplice list1 list2))) ((and (eq? (first list1) (first list2)) (eq? (last1 list1) (last1 list2))) (apply m (cyclicsplice (reverse list1) list2))) (else #f)))) Test the procedures to see if they work. ;;; where cyclicrotate(list) is cyclic rotation of the list one step ;;; by putting the first element at the end (define (cyclicrotate list1) (append (rest list1) (list (first list1)))) ;;; and where term_min(list) is the element of the list which is ;;; first in the term ordering. (define (term_min list1) (car (sort list1 term<))) (define (term< sym1 sym2) (string<? (symbol->string sym1) (symbol->string sym2))) (define first car) (define rest cdr) (define (last1 list1) (car (last-pair list1))) (define (neq? obj1 obj2) (not (eq? obj1 obj2))) ;;; where splice is the concatenation of list1 and list2 except that their ;;; common element is not repeated. (define (splice list1 list2) (cond ((eq? (last1 list1) (first list2)) (append list1 (cdr list2))) (else (error 'splice list1 list2)))) ;;; where cyclicsplice is the result of leaving off the last element of ;;; splice(list1,list2). (define (cyclicsplice list1 list2) (cond ((and (eq? (last1 list1) (first list2)) (eq? (first list1) (last1 list2))) (butlast (splice list1 list2) 1)) (else (error 'cyclicsplice list1 list2)))) (N*N (S a b) (S a b)) => (m a b) Then register the rule for multiplying type N objects by type N objects. (cring:define-rule '* 'N 'N N*N)) Now we are ready to compute! (define (t) (define detM (+ (* (S g b) (+ (* (S f d) (- (* (S a f) (S d g)) (* (S a g) (S d f)))) (* (S f f) (- (* (S a g) (S d d)) (* (S a d) (S d g)))) (* (S f g) (- (* (S a d) (S d f)) (* (S a f) (S d d)))))) (* (S g d) (+ (* (S f b) (- (* (S a g) (S d f)) (* (S a f) (S d g)))) (* (S f f) (- (* (S a b) (S d g)) (* (S a g) (S d b)))) (* (S f g) (- (* (S a f) (S d b)) (* (S a b) (S d f)))))) (* (S g f) (+ (* (S f b) (- (* (S a d) (S d g)) (* (S a g) (S d d)))) (* (S f d) (- (* (S a g) (S d b)) (* (S a b) (S d g)))) (* (S f g) (- (* (S a b) (S d d)) (* (S a d) (S d b)))))) (* (S g g) (+ (* (S f b) (- (* (S a f) (S d d)) (* (S a d) (S d f)))) (* (S f d) (- (* (S a b) (S d f)) (* (S a f) (S d b)))) (* (S f f) (- (* (S a d) (S d b)) (* (S a b) (S d d)))))))) (* (S b e) (S c a) (S e c) detM )) (pretty-print (t)) -| (- (+ (m a c e b d f g) (m a c e b d g f) (m a c e b f d g) (m a c e b f g d) (m a c e b g d f) (m a c e b g f d)) (* 2 (m a b e c) (m d f g)) (* (m a c e b d) (m f g)) (* (m a c e b f) (m d g)) (* (m a c e b g) (m d f))) File: slib.info, Node: Determinant, Prev: Commutative Rings, Up: Mathematical Packages Determinant =========== (require 'determinant) (determinant '((1 2) (3 4))) => -2 (determinant '((1 2 3) (4 5 6) (7 8 9))) => 0 (determinant '((1 2 3 4) (5 6 7 8) (9 10 11 12))) => 0 File: slib.info, Node: Database Packages, Next: Other Packages, Prev: Mathematical Packages, Up: Top Database Packages ***************** * Menu: * Base Table:: * Relational Database:: 'relational-database * Weight-Balanced Trees:: 'wt-tree File: slib.info, Node: Base Table, Next: Relational Database, Prev: Database Packages, Up: Database Packages Base Table ========== A base table implementation using Scheme association lists is available as the value of the identifier `alist-table' after doing: `(require 'alist-table)' Association list base tables are suitable for small databases and support all Scheme types when temporary and readable/writeable Scheme types when saved. I hope support for other base table implementations will be added in the future. This rest of this section documents the interface for a base table implementation from which the *Note Relational Database:: package constructs a Relational system. It will be of interest primarily to those wishing to port or write new base-table implementations. All of these functions are accessed through a single procedure by calling that procedure with the symbol name of the operation. A procedure will be returned if that operation is supported and `#f' otherwise. For example: (require 'alist-table) (define open-base (alist-table 'make-base)) make-base => *a procedure* (define foo (alist-table 'foo)) foo => #f - Function: make-base FILENAME KEY-DIMENSION COLUMN-TYPES Returns a new, open, low-level database (collection of tables) associated with FILENAME. This returned database has an empty table associated with CATALOG-ID. The positive integer KEY-DIMENSION is the number of keys composed to make a PRIMARY-KEY for the catalog table. The list of symbols COLUMN-TYPES describes the types of each column for that table. If the database cannot be created as specified, `#f' is returned. Calling the `close-base' method on this database and possibly other operations will cause FILENAME to be written to. If FILENAME is `#f' a temporary, non-disk based database will be created if such can be supported by the base table implelentation. - Function: open-base FILENAME MUTABLE Returns an open low-level database associated with FILENAME. If MUTABLE? is `#t', this database will have methods capable of effecting change to the database. If MUTABLE? is `#f', only methods for inquiring the database will be available. If the database cannot be opened as specified `#f' is returned. Calling the `close-base' (and possibly other) method on a MUTABLE? database will cause FILENAME to be written to. - Function: write-base LLDB FILENAME Causes the low-level database LLDB to be written to FILENAME. If the write is successful, also causes LLDB to henceforth be associated with FILENAME. Calling the `close-database' (and possibly other) method on LLDB may cause FILENAME to be written to. If FILENAME is `#f' this database will be changed to a temporary, non-disk based database if such can be supported by the underlying base table implelentation. If the operations completed successfully, `#t' is returned. Otherwise, `#f' is returned. - Function: sync-base LLDB Causes the file associated with the low-level database LLDB to be updated to reflect its current state. If the associated filename is `#f', no action is taken and `#f' is returned. If this operation completes successfully, `#t' is returned. Otherwise, `#f' is returned. - Function: close-base LLDB Causes the low-level database LLDB to be written to its associated file (if any). If the write is successful, subsequent operations to LLDB will signal an error. If the operations complete successfully, `#t' is returned. Otherwise, `#f' is returned. - Function: make-table LLDB KEY-DIMENSION COLUMN-TYPES Returns the BASE-ID for a new base table, otherwise returns `#f'. The base table can then be opened using `(open-table LLDB BASE-ID)'. The positive integer KEY-DIMENSION is the number of keys composed to make a PRIMARY-KEY for this table. The list of symbols COLUMN-TYPES describes the types of each column. - Constant: catalog-id A constant BASE-ID suitable for passing as a parameter to `open-table'. CATALOG-ID will be used as the base table for the system catalog. - Function: open-table LLDB BASE-ID KEY-DIMENSION COLUMN-TYPES Returns a HANDLE for an existing base table in the low-level database LLDB if that table exists and can be opened in the mode indicated by MUTABLE?, otherwise returns `#f'. As with `make-table', the positive integer KEY-DIMENSION is the number of keys composed to make a PRIMARY-KEY for this table. The list of symbols COLUMN-TYPES describes the types of each column. - Function: kill-table LLDB BASE-ID KEY-DIMENSION COLUMN-TYPES Returns `#t' if the base table associated with BASE-ID was removed from the low level database LLDB, and `#f' otherwise. - Function: make-keyifier-1 TYPE Returns a procedure which accepts a single argument which must be of type TYPE. This returned procedure returns an object suitable for being a KEY argument in the functions whose descriptions follow. Any 2 arguments of the supported type passed to the returned function which are not `equal?' must result in returned values which are not `equal?'. - Function: make-list-keyifier KEY-DIMENSION TYPES The list of symbols TYPES must have at least KEY-DIMENSION elements. Returns a procedure which accepts a list of length KEY-DIMENSION and whose types must corresopond to the types named by TYPES. This returned procedure combines the elements of its list argument into an object suitable for being a KEY argument in the functions whose descriptions follow. Any 2 lists of supported types (which must at least include symbols and non-negative integers) passed to the returned function which are not `equal?' must result in returned values which are not `equal?'. - Function: make-key-extractor KEY-DIMENSION TYPES COLUMN-NUMBER Returns a procedure which accepts objects produced by application of the result of `(make-list-keyifier KEY-DIMENSION TYPES)'. This procedure returns a KEY which is `equal?' to the COLUMN-NUMBERth element of the list which was passed to create COMBINED-KEY. The list TYPES must have at least KEY-DIMENSION elements. - Function: make-key->list KEY-DIMENSION TYPES Returns a procedure which accepts objects produced by application of the result of `(make-list-keyifier KEY-DIMENSION TYPES)'. This procedure returns a list of KEYs which are elementwise `equal?' to the list which was passed to create COMBINED-KEY. In the following functions, the KEY argument can always be assumed to be the value returned by a call to a *keyify* routine. In contrast, a MATCH-KEY argument is a list of length equal to the number of primary keys. The MATCH-KEY restricts the actions of the table command to those records whose primary keys all satisfy the corresponding element of the MATCH-KEY list. The elements and their actions are: `#f' The false value matches any key in the corresponding position. an object of type procedure This procedure must take a single argument, the key in the corresponding position. Any key for which the procedure returns a non-false value is a match; Any key for which the procedure returns a `#f' is not. other values Any other value matches only those keys `equal?' to it. - Function: for-each-key HANDLE PROCEDURE MATCH-KEY Calls PROCEDURE once with each KEY in the table opened in HANDLE which satisfies MATCH-KEY in an unspecified order. An unspecified value is returned. - Function: map-key HANDLE PROCEDURE MATCH-KEY Returns a list of the values returned by calling PROCEDURE once with each KEY in the table opened in HANDLE which satisfies MATCH-KEY in an unspecified order. - Function: ordered-for-each-key HANDLE PROCEDURE MATCH-KEY Calls PROCEDURE once with each KEY in the table opened in HANDLE which satisfies MATCH-KEY in the natural order for the types of the primary key fields of that table. An unspecified value is returned. - Function: delete* HANDLE MATCH-KEY Removes all rows which satisfy MATCH-KEY from the table opened in HANDLE. An unspecified value is returned. - Function: present? HANDLE KEY Returns a non-`#f' value if there is a row associated with KEY in the table opened in HANDLE and `#f' otherwise. - Function: delete HANDLE KEY Removes the row associated with KEY from the table opened in HANDLE. An unspecified value is returned. - Function: make-getter KEY-DIMENSION TYPES Returns a procedure which takes arguments HANDLE and KEY. This procedure returns a list of the non-primary values of the relation (in the base table opened in HANDLE) whose primary key is KEY if it exists, and `#f' otherwise. - Function: make-putter KEY-DIMENSION TYPES Returns a procedure which takes arguments HANDLE and KEY and VALUE-LIST. This procedure associates the primary key KEY with the values in VALUE-LIST (in the base table opened in HANDLE) and returns an unspecified value. - Function: supported-type? SYMBOL Returns `#t' if SYMBOL names a type allowed as a column value by the implementation, and `#f' otherwise. At a minimum, an implementation must support the types `integer', `symbol', `string', `boolean', and `base-id'. - Function: supported-key-type? SYMBOL Returns `#t' if SYMBOL names a type allowed as a key value by the implementation, and `#f' otherwise. At a minimum, an implementation must support the types `integer', and `symbol'. `integer' Scheme exact integer. `symbol' Scheme symbol. `boolean' `#t' or `#f'. `base-id' Objects suitable for passing as the BASE-ID parameter to `open-table'. The value of CATALOG-ID must be an acceptable `base-id'. File: slib.info, Node: Relational Database, Next: Weight-Balanced Trees, Prev: Base Table, Up: Database Packages Relational Database =================== `(require 'relational-database)' This package implements a database system inspired by the Relational Model (`E. F. Codd, A Relational Model of Data for Large Shared Data Banks'). An SLIB relational database implementation can be created from any *Note Base Table:: implementation. * Menu: * Motivations:: Database Manifesto * Creating and Opening Relational Databases:: * Relational Database Operations:: * Table Operations:: * Catalog Representation:: * Unresolved Issues:: * Database Utilities:: 'database-utilities * Database Reports:: * Database Browser:: 'database-browse File: slib.info, Node: Motivations, Next: Creating and Opening Relational Databases, Prev: Relational Database, Up: Relational Database Motivations ----------- Most nontrivial programs contain databases: Makefiles, configure scripts, file backup, calendars, editors, source revision control, CAD systems, display managers, menu GUIs, games, parsers, debuggers, profilers, and even error reporting are all rife with databases. Coding databases is such a common activity in programming that many may not be aware of how often they do it. A database often starts as a dispatch in a program. The author, perhaps because of the need to make the dispatch configurable, the need for correlating dispatch in other routines, or because of changes or growth, devises a data structure to contain the information, a routine for interpreting that data structure, and perhaps routines for augmenting and modifying the stored data. The dispatch must be converted into this form and tested. The programmer may need to devise an interactive program for enabling easy examination and modification of the information contained in this database. Often, in an attempt to foster modularity and avoid delays in release, intermediate file formats for the database information are devised. It often turns out that users prefer modifying these intermediate files with a text editor to using the interactive program in order to do operations (such as global changes) not forseen by the program's author. In order to address this need, the conscientious software engineer may even provide a scripting language to allow users to make repetitive database changes. Users will grumble that they need to read a large manual and learn yet another programming language (even if it *almost* has language "xyz" syntax) in order to do simple configuration. All of these facilities need to be designed, coded, debugged, documented, and supported; often causing what was very simple in concept to become a major developement project. This view of databases just outlined is somewhat the reverse of the view of the originators of the "Relational Model" of database abstraction. The relational model was devised to unify and allow interoperation of large multi-user databases running on diverse platforms. A fairly general purpose "Comprehensive Language" for database manipulations is mandated (but not specified) as part of the relational model for databases. One aspect of the Relational Model of some importance is that the "Comprehensive Language" must be expressible in some form which can be stored in the database. This frees the programmer from having to make programs data-driven in order to use a database. This package includes as one of its basic supported types Scheme "expression"s. This type allows expressions as defined by the Scheme standards to be stored in the database. Using `slib:eval' retrieved expressions can be evaluated (in the top-level environment). Scheme's `lambda' facilitates closure of environments, modularity, etc. so that procedures (which could not be stored directly most databases) can still be effectively retrieved. Since `slib:eval' evaluates expressions in the top-level environment, built-in and user defined procedures can be easily accessed by name. This package's purpose is to standardize (through a common interface) database creation and usage in Scheme programs. The relational model's provision for inclusion of language expressions as data as well as the description (in tables, of course) of all of its tables assures that relational databases are powerful enough to assume the roles currently played by thousands of ad-hoc routines and data formats. Such standardization to a relational-like model brings many benefits: * Tables, fields, domains, and types can be dealt with by name in programs. * The underlying database implementation can be changed (for performance or other reasons) by changing a single line of code. * The formats of tables can be easily extended or changed without altering code. * Consistency checks are specified as part of the table descriptions. Changes in checks need only occur in one place. * All the configuration information which the developer wishes to group together is easily grouped, without needing to change programs aware of only some of these tables. * Generalized report generators, interactive entry programs, and other database utilities can be part of a shared library. The burden of adding configurability to a program is greatly reduced. * Scheme is the "comprehensive language" for these databases. Scripting for configuration no longer needs to be in a separate language with additional documentation. * Scheme's latent types mesh well with the strict typing and logical requirements of the relational model. * Portable formats allow easy interchange of data. The included table descriptions help prevent misinterpretation of format. File: slib.info, Node: Creating and Opening Relational Databases, Next: Relational Database Operations, Prev: Motivations, Up: Relational Database Creating and Opening Relational Databases ----------------------------------------- - Function: make-relational-system BASE-TABLE-IMPLEMENTATION Returns a procedure implementing a relational database using the BASE-TABLE-IMPLEMENTATION. All of the operations of a base table implementation are accessed through a procedure defined by `require'ing that implementation. Similarly, all of the operations of the relational database implementation are accessed through the procedure returned by `make-relational-system'. For instance, a new relational database could be created from the procedure returned by `make-relational-system' by: (require 'alist-table) (define relational-alist-system (make-relational-system alist-table)) (define create-alist-database (relational-alist-system 'create-database)) (define my-database (create-alist-database "mydata.db")) What follows are the descriptions of the methods available from relational system returned by a call to `make-relational-system'. - Function: create-database FILENAME Returns an open, nearly empty relational database associated with FILENAME. The only tables defined are the system catalog and domain table. Calling the `close-database' method on this database and possibly other operations will cause FILENAME to be written to. If FILENAME is `#f' a temporary, non-disk based database will be created if such can be supported by the underlying base table implelentation. If the database cannot be created as specified `#f' is returned. For the fields and layout of descriptor tables, *Note Catalog Representation:: - Function: open-database FILENAME MUTABLE? Returns an open relational database associated with FILENAME. If MUTABLE? is `#t', this database will have methods capable of effecting change to the database. If MUTABLE? is `#f', only methods for inquiring the database will be available. Calling the `close-database' (and possibly other) method on a MUTABLE? database will cause FILENAME to be written to. If the database cannot be opened as specified `#f' is returned. File: slib.info, Node: Relational Database Operations, Next: Table Operations, Prev: Creating and Opening Relational Databases, Up: Relational Database Relational Database Operations ------------------------------ These are the descriptions of the methods available from an open relational database. A method is retrieved from a database by calling the database with the symbol name of the operation. For example: (define my-database (create-alist-database "mydata.db")) (define telephone-table-desc ((my-database 'create-table) 'telephone-table-desc)) - Function: close-database Causes the relational database to be written to its associated file (if any). If the write is successful, subsequent operations to this database will signal an error. If the operations completed successfully, `#t' is returned. Otherwise, `#f' is returned. - Function: write-database FILENAME Causes the relational database to be written to FILENAME. If the write is successful, also causes the database to henceforth be associated with FILENAME. Calling the `close-database' (and possibly other) method on this database will cause FILENAME to be written to. If FILENAME is `#f' this database will be changed to a temporary, non-disk based database if such can be supported by the underlying base table implelentation. If the operations completed successfully, `#t' is returned. Otherwise, `#f' is returned. - Function: table-exists? TABLE-NAME Returns `#t' if TABLE-NAME exists in the system catalog, otherwise returns `#f'. - Function: open-table TABLE-NAME MUTABLE? Returns a "methods" procedure for an existing relational table in this database if it exists and can be opened in the mode indicated by MUTABLE?, otherwise returns `#f'. These methods will be present only in databases which are MUTABLE?. - Function: delete-table TABLE-NAME Removes and returns the TABLE-NAME row from the system catalog if the table or view associated with TABLE-NAME gets removed from the database, and `#f' otherwise. - Function: create-table TABLE-DESC-NAME Returns a methods procedure for a new (open) relational table for describing the columns of a new base table in this database, otherwise returns `#f'. For the fields and layout of descriptor tables, *Note Catalog Representation::. - Function: create-table TABLE-NAME TABLE-DESC-NAME Returns a methods procedure for a new (open) relational table with columns as described by TABLE-DESC-NAME, otherwise returns `#f'. - Function: create-view ?? - Function: project-table ?? - Function: restrict-table ?? - Function: cart-prod-tables ?? Not yet implemented. File: slib.info, Node: Table Operations, Next: Catalog Representation, Prev: Relational Database Operations, Up: Relational Database Table Operations ---------------- These are the descriptions of the methods available from an open relational table. A method is retrieved from a table by calling the table with the symbol name of the operation. For example: (define telephone-table-desc ((my-database 'create-table) 'telephone-table-desc)) (require 'common-list-functions) (define ndrp (telephone-table-desc 'row:insert)) (ndrp '(1 #t name #f string)) (ndrp '(2 #f telephone (lambda (d) (and (string? d) (> (string-length d) 2) (every (lambda (c) (memv c '(#\0 #\1 #\2 #\3 #\4 #\5 #\6 #\7 #\8 #\9 #\+ #$ #\ #$ #\-))) (string->list d)))) string)) Some operations described below require primary key arguments. Primary keys arguments are denoted KEY1 KEY2 .... It is an error to call an operation for a table which takes primary key arguments with the wrong number of primary keys for that table. The term "row" used below refers to a Scheme list of values (one for each column) in the order specified in the descriptor (table) for this table. Missing values appear as `#f'. Primary keys must not be missing. - Function: get COLUMN-NAME Returns a procedure of arguments KEY1 KEY2 ... which returns the value for the COLUMN-NAME column of the row associated with primary keys KEY1, KEY2 ... if that row exists in the table, or `#f' otherwise. ((plat 'get 'processor) 'djgpp) => i386 ((plat 'get 'processor) 'be-os) => #f - Function: get* COLUMN-NAME Returns a procedure of optional arguments MATCH-KEY1 ... which returns a list of the values for the specified column for all rows in this table. The optional MATCH-KEY1 ... arguments restrict actions to a subset of the table. See the match-key description below for details. ((plat 'get* 'processor)) => (i386 8086 i386 8086 i386 i386 8086 m68000 m68000 m68000 m68000 m68000 powerpc) ((plat 'get* 'processor) #f) => (i386 8086 i386 8086 i386 i386 8086 m68000 m68000 m68000 m68000 m68000 powerpc) (define (a-key? key) (char=? #\a (string-ref (symbol->string key) 0))) ((plat 'get* 'processor) a-key?) => (m68000 m68000 m68000 m68000 m68000 powerpc) ((plat 'get* 'name) a-key?) => (atari-st-turbo-c atari-st-gcc amiga-sas/c-5.10 amiga-aztec amiga-dice-c aix) - Function: row:retrieve Returns a procedure of arguments KEY1 KEY2 ... which returns the row associated with primary keys KEY1, KEY2 ... if it exists, or `#f' otherwise. ((plat 'row:retrieve) 'linux) => (linux i386 linux gcc) ((plat 'row:retrieve) 'multics) => #f - Function: row:retrieve* Returns a procedure of optional arguments MATCH-KEY1 ... which returns a list of all rows in this table. The optional MATCH-KEY1 ... arguments restrict actions to a subset of the table. See the match-key description below for details. ((plat 'row:retrieve*) a-key?) => ((atari-st-turbo-c m68000 atari turbo-c) (atari-st-gcc m68000 atari gcc) (amiga-sas/c-5.10 m68000 amiga sas/c) (amiga-aztec m68000 amiga aztec) (amiga-dice-c m68000 amiga dice-c) (aix powerpc aix -)) - Function: row:remove Returns a procedure of arguments KEY1 KEY2 ... which removes and returns the row associated with primary keys KEY1, KEY2 ... if it exists, or `#f' otherwise. - Function: row:remove* Returns a procedure of optional arguments MATCH-KEY1 ... which removes and returns a list of all rows in this table. The optional MATCH-KEY1 ... arguments restrict actions to a subset of the table. See the match-key description below for details. - Function: row:delete Returns a procedure of arguments KEY1 KEY2 ... which deletes the row associated with primary keys KEY1, KEY2 ... if it exists. The value returned is unspecified. - Function: row:delete* Returns a procedure of optional arguments MATCH-KEY1 ... which Deletes all rows from this table. The optional MATCH-KEY1 ... arguments restrict deletions to a subset of the table. See the match-key description below for details. The value returned is unspecified. The descriptor table and catalog entry for this table are not affected. - Function: row:update Returns a procedure of one argument, ROW, which adds the row, ROW, to this table. If a row for the primary key(s) specified by ROW already exists in this table, it will be overwritten. The value returned is unspecified. - Function: row:update* Returns a procedure of one argument, ROWS, which adds each row in the list of rows, ROWS, to this table. If a row for the primary key specified by an element of ROWS already exists in this table, it will be overwritten. The value returned is unspecified. - Function: row:insert Adds the row ROW to this table. If a row for the primary key(s) specified by ROW already exists in this table an error is signaled. The value returned is unspecified. - Function: row:insert* Returns a procedure of one argument, ROWS, which adds each row in the list of rows, ROWS, to this table. If a row for the primary key specified by an element of ROWS already exists in this table, an error is signaled. The value returned is unspecified. - Function: for-each-row Returns a procedure of arguments PROC MATCH-KEY1 ... which calls PROC with each ROW in this table in the (implementation-dependent) natural ordering for rows. The optional MATCH-KEY1 ... arguments restrict actions to a subset of the table. See the match-key description below for details. *Real* relational programmers would use some least-upper-bound join for every row to get them in order; But we don't have joins yet. The (optional) MATCH-KEY1 ... arguments are used to restrict actions of a whole-table operation to a subset of that table. Those procedures (returned by methods) which accept match-key arguments will accept any number of match-key arguments between zero and the number of primary keys in the table. Any unspecified MATCH-KEY arguments default to `#f'. The MATCH-KEY1 ... restrict the actions of the table command to those records whose primary keys each satisfy the corresponding MATCH-KEY argument. The arguments and their actions are: `#f' The false value matches any key in the corresponding position. an object of type procedure This procedure must take a single argument, the key in the corresponding position. Any key for which the procedure returns a non-false value is a match; Any key for which the procedure returns a `#f' is not. other values Any other value matches only those keys `equal?' to it. - Function: close-table Subsequent operations to this table will signal an error. - Constant: column-names - Constant: column-foreigns - Constant: column-domains - Constant: column-types Return a list of the column names, foreign-key table names, domain names, or type names respectively for this table. These 4 methods are different from the others in that the list is returned, rather than a procedure to obtain the list. - Constant: primary-limit Returns the number of primary keys fields in the relations in this table. File: slib.info, Node: Catalog Representation, Next: Unresolved Issues, Prev: Table Operations, Up: Relational Database Catalog Representation ---------------------- Each database (in an implementation) has a "system catalog" which describes all the user accessible tables in that database (including itself). The system catalog base table has the following fields. `PRI' indicates a primary key for that table. PRI table-name column-limit the highest column number coltab-name descriptor table name bastab-id data base table identifier user-integrity-rule view-procedure A scheme thunk which, when called, produces a handle for the view. coltab and bastab are specified if and only if view-procedure is not. Descriptors for base tables (not views) are tables (pointed to by system catalog). Descriptor (base) tables have the fields: PRI column-number sequential integers from 1 primary-key? boolean TRUE for primary key components column-name column-integrity-rule domain-name A "primary key" is any column marked as `primary-key?' in the corresponding descriptor table. All the `primary-key?' columns must have lower column numbers than any non-`primary-key?' columns. Every table must have at least one primary key. Primary keys must be sufficient to distinguish all rows from each other in the table. All of the system defined tables have a single primary key. This package currently supports tables having from 1 to 4 primary keys if there are non-primary columns, and any (natural) number if *all* columns are primary keys. If you need more than 4 primary keys, I would like to hear what you are doing! A "domain" is a category describing the allowable values to occur in a column. It is described by a (base) table with the fields: PRI domain-name foreign-table domain-integrity-rule type-id type-param The "type-id" field value is a symbol. This symbol may be used by the underlying base table implementation in storing that field. If the `foreign-table' field is non-`#f' then that field names a table from the catalog. The values for that domain must match a primary key of the table referenced by the TYPE-PARAM (or `#f', if allowed). This package currently does not support composite foreign-keys. The types for which support is planned are: atom symbol string [<length>] number [<base>] money <currency> date-time boolean foreign-key <table-name> expression virtual <expression> File: slib.info, Node: Unresolved Issues, Next: Database Utilities, Prev: Catalog Representation, Up: Relational Database Unresolved Issues ----------------- Although `rdms.scm' is not large, I found it very difficult to write (six rewrites). I am not aware of any other examples of a generalized relational system (although there is little new in CS). I left out several aspects of the Relational model in order to simplify the job. The major features lacking (which might be addressed portably) are views, transaction boundaries, and protection. Protection needs a model for specifying priveledges. Given how operations are accessed from handles it should not be difficult to restrict table accesses to those allowed for that user. The system catalog has a field called `view-procedure'. This should allow a purely functional implementation of views. This will work but is unsatisfying for views resulting from a "select"ion (subset of rows); for whole table operations it will not be possible to reduce the number of keys scanned over when the selection is specified only by an opaque procedure. Transaction boundaries present the most intriguing area. Transaction boundaries are actually a feature of the "Comprehensive Language" of the Relational database and not of the database. Scheme would seem to provide the opportunity for an extremely clean semantics for transaction boundaries since the builtin procedures with side effects are small in number and easily identified. These side-effect builtin procedures might all be portably redefined to versions which properly handled transactions. Compiled library routines would need to be recompiled as well. Many system extensions (delete-file, system, etc.) would also need to be redefined. There are 2 scope issues that must be resolved for multiprocess transaction boundaries: Process scope The actions captured by a transaction should be only for the process which invoked the start of transaction. Although standard Scheme does not provide process primitives as such, `dynamic-wind' would provide a workable hook into process switching for many implementations. Shared utilities with state Some shared utilities have state which should *not* be part of a transaction. An example would be calling a pseudo-random number generator. If the success of a transaction depended on the pseudo-random number and failed, the state of the generator would be set back. Subsequent calls would keep returning the same number and keep failing. Pseudo-random number generators are not reentrant; thus they would require locks in order to operate properly in a multiprocess environment. Are all examples of utilities whose state should not be part of transactions also non-reentrant? If so, perhaps suspending transaction capture for the duration of locks would solve this problem. File: slib.info, Node: Database Utilities, Next: Database Reports, Prev: Unresolved Issues, Up: Relational Database Database Utilities ------------------ `(require 'database-utilities)' This enhancement wraps a utility layer on `relational-database' which provides: * Automatic loading of the appropriate base-table package when opening a database. * Automatic execution of initialization commands stored in database. * Transparent execution of database commands stored in `*commands*' table in database. Also included are utilities which provide: * Data definition from Scheme lists and * Report generation for any SLIB relational database. - Function: create-database FILENAME BASE-TABLE-TYPE Returns an open, nearly empty enhanced (with `*commands*' table) relational database (with base-table type BASE-TABLE-TYPE) associated with FILENAME. - Function: open-database FILENAME - Function: open-database FILENAME BASE-TABLE-TYPE Returns an open enchanced relational database associated with FILENAME. The database will be opened with base-table type BASE-TABLE-TYPE) if supplied. If BASE-TABLE-TYPE is not supplied, `open-database' will attempt to deduce the correct base-table-type. If the database can not be opened or if it lacks the `*commands*' table, `#f' is returned. - Function: open-database! FILENAME - Function: open-database! FILENAME BASE-TABLE-TYPE Returns *mutable* open enchanced relational database ... The table `*commands*' in an "enhanced" relational-database has the fields (with domains): PRI name symbol parameters parameter-list procedure expression documentation string The `parameters' field is a foreign key (domain `parameter-list') of the `*catalog-data*' table and should have the value of a table described by `*parameter-columns*'. This `parameter-list' table describes the arguments suitable for passing to the associated command. The intent of this table is to be of a form such that different user-interfaces (for instance, pull-down menus or plain-text queries) can operate from the same table. A `parameter-list' table has the following fields: PRI index uint name symbol arity parameter-arity domain domain defaulter expression expander expression documentation string The `arity' field can take the values: `single' Requires a single parameter of the specified domain. `optional' A single parameter of the specified domain or zero parameters is acceptable. `boolean' A single boolean parameter or zero parameters (in which case `#f' is substituted) is acceptable. `nary' Any number of parameters of the specified domain are acceptable. The argument passed to the command function is always a list of the parameters. `nary1' One or more of parameters of the specified domain are acceptable. The argument passed to the command function is always a list of the parameters. The `domain' field specifies the domain which a parameter or parameters in the `index'th field must satisfy. The `defaulter' field is an expression whose value is either `#f' or a procedure of one argument (the parameter-list) which returns a *list* of the default value or values as appropriate. Note that since the `defaulter' procedure is called every time a default parameter is needed for this column, "sticky" defaults can be implemented using shared state with the domain-integrity-rule. Invoking Commands ................. When an enhanced relational-database is called with a symbol which matches a NAME in the `*commands*' table, the associated procedure expression is evaluated and applied to the enhanced relational-database. A procedure should then be returned which the user can invoke on (optional) arguments. The command `*initialize*' is special. If present in the `*commands*' table, `open-database' or `open-database!' will return the value of the `*initialize*' command. Notice that arbitrary code can be run when the `*initialize*' procedure is automatically applied to the enhanced relational-database. Note also that if you wish to shadow or hide from the user relational-database methods described in *Note Relational Database Operations::, this can be done by a dispatch in the closure returned by the `*initialize*' expression rather than by entries in the `*commands*' table if it is desired that the underlying methods remain accessible to code in the `*commands*' table. - Function: make-command-server RDB TABLE-NAME Returns a procedure of 2 arguments, a (symbol) command and a call-back procedure. When this returned procedure is called, it looks up COMMAND in table TABLE-NAME and calls the call-back procedure with arguments: COMMAND The COMMAND COMMAND-VALUE The result of evaluating the expression in the PROCEDURE field of TABLE-NAME and calling it with RDB. PARAMETER-NAME A list of the "official" name of each parameter. Corresponds to the `name' field of the COMMAND's parameter-table. POSITIONS A list of the positive integer index of each parameter. Corresponds to the `index' field of the COMMAND's parameter-table. ARITIES A list of the arities of each parameter. Corresponds to the `arity' field of the COMMAND's parameter-table. For a description of `arity' see table above. TYPES A list of the type name of each parameter. Correspnds to the `type-id' field of the contents of the `domain' of the COMMAND's parameter-table. DEFAULTERS A list of the defaulters for each parameter. Corresponds to the `defaulters' field of the COMMAND's parameter-table. DOMAIN-INTEGRITY-RULES A list of procedures (one for each parameter) which tests whether a value for a parameter is acceptable for that parameter. The procedure should be called with each datum in the list for `nary' arity parameters. ALIASES A list of lists of `(alias parameter-name)'. There can be more than one alias per PARAMETER-NAME. For information about parameters, *Note Parameter lists::. Here is an example of setting up a command with arguments and parsing those arguments from a `getopt' style argument list (*note Getopt::.). (require 'database-utilities) (require 'fluid-let) (require 'parameters) (require 'getopt) (define my-rdb (create-database #f 'alist-table)) (define-tables my-rdb '(foo-params *parameter-columns* *parameter-columns* ((1 single-string single string (lambda (pl) '("str")) #f "single string") (2 nary-symbols nary symbol (lambda (pl) '()) #f "zero or more symbols") (3 nary1-symbols nary1 symbol (lambda (pl) '(symb)) #f "one or more symbols") (4 optional-number optional uint (lambda (pl) '()) #f "zero or one number") (5 flag boolean boolean (lambda (pl) '(#f)) #f "a boolean flag"))) '(foo-pnames ((name string)) ((parameter-index uint)) (("s" 1) ("single-string" 1) ("n" 2) ("nary-symbols" 2) ("N" 3) ("nary1-symbols" 3) ("o" 4) ("optional-number" 4) ("f" 5) ("flag" 5))) '(my-commands ((name symbol)) ((parameters parameter-list) (parameter-names parameter-name-translation) (procedure expression) (documentation string)) ((foo foo-params foo-pnames (lambda (rdb) (lambda args (print args))) "test command arguments")))) (define (dbutil:serve-command-line rdb command-table command argc argv) (set! argv (if (vector? argv) (vector->list argv) argv)) ((make-command-server rdb command-table) command (lambda (comname comval options positions arities types defaulters dirs aliases) (apply comval (getopt->arglist argc argv options positions arities types defaulters dirs aliases))))) (define (cmd . opts) (fluid-let ((*optind* 1)) (printf "%-34s => " (call-with-output-string (lambda (pt) (write (cons 'cmd opts) pt)))) (set! opts (cons "cmd" opts)) (force-output) (dbutil:serve-command-line my-rdb 'my-commands 'foo (length opts) opts))) (cmd) => ("str" () (symb) () #f) (cmd "-f") => ("str" () (symb) () #t) (cmd "--flag") => ("str" () (symb) () #t) (cmd "-o177") => ("str" () (symb) (177) #f) (cmd "-o" "177") => ("str" () (symb) (177) #f) (cmd "--optional" "621") => ("str" () (symb) (621) #f) (cmd "--optional=621") => ("str" () (symb) (621) #f) (cmd "-s" "speciality") => ("speciality" () (symb) () #f) (cmd "-sspeciality") => ("speciality" () (symb) () #f) (cmd "--single" "serendipity") => ("serendipity" () (symb) () #f) (cmd "--single=serendipity") => ("serendipity" () (symb) () #f) (cmd "-n" "gravity" "piety") => ("str" () (piety gravity) () #f) (cmd "-ngravity" "piety") => ("str" () (piety gravity) () #f) (cmd "--nary" "chastity") => ("str" () (chastity) () #f) (cmd "--nary=chastity" "") => ("str" () ( chastity) () #f) (cmd "-N" "calamity") => ("str" () (calamity) () #f) (cmd "-Ncalamity") => ("str" () (calamity) () #f) (cmd "--nary1" "surety") => ("str" () (surety) () #f) (cmd "--nary1=surety") => ("str" () (surety) () #f) (cmd "-N" "levity" "fealty") => ("str" () (fealty levity) () #f) (cmd "-Nlevity" "fealty") => ("str" () (fealty levity) () #f) (cmd "--nary1" "surety" "brevity") => ("str" () (brevity surety) () #f) (cmd "--nary1=surety" "brevity") => ("str" () (brevity surety) () #f) (cmd "-?") -| Usage: cmd [OPTION ARGUMENT ...] ... -f, --flag -o, --optional[=]<number> -n, --nary[=]<symbols> ... -N, --nary1[=]<symbols> ... -s, --single[=]<string> ERROR: getopt->parameter-list "unrecognized option" "-?" Some commands are defined in all extended relational-databases. The are called just like *Note Relational Database Operations::. - Function: add-domain DOMAIN-ROW Adds DOMAIN-ROW to the "domains" table if there is no row in the domains table associated with key `(car DOMAIN-ROW)' and returns `#t'. Otherwise returns `#f'. For the fields and layout of the domain table, *Note Catalog Representation::. Currently, these fields are * domain-name * foreign-table * domain-integrity-rule * type-id * type-param The following example adds 3 domains to the `build' database. `Optstring' is either a string or `#f'. `filename' is a string and `build-whats' is a symbol. (for-each (build 'add-domain) '((optstring #f (lambda (x) (or (not x) (string? x))) string #f) (filename #f #f string #f) (build-whats #f #f symbol #f))) - Function: delete-domain DOMAIN-NAME Removes and returns the DOMAIN-NAME row from the "domains" table. - Function: domain-checker DOMAIN Returns a procedure to check an argument for conformance to domain DOMAIN. Defining Tables ............... - Procedure: define-tables RDB SPEC-0 ... Adds tables as specified in SPEC-0 ... to the open relational-database RDB. Each SPEC has the form: (<name> <descriptor-name> <descriptor-name> <rows>) or (<name> <primary-key-fields> <other-fields> <rows>) where <name> is the table name, <descriptor-name> is the symbol name of a descriptor table, <primary-key-fields> and <other-fields> describe the primary keys and other fields respectively, and <rows> is a list of data rows to be added to the table. <primary-key-fields> and <other-fields> are lists of field descriptors of the form: (<column-name> <domain>) or (<column-name> <domain> <column-integrity-rule>) where <column-name> is the column name, <domain> is the domain of the column, and <column-integrity-rule> is an expression whose value is a procedure of one argument (which returns `#f' to signal an error). If <domain> is not a defined domain name and it matches the name of this table or an already defined (in one of SPEC-0 ...) single key field table, a foriegn-key domain will be created for it. The following example shows a new database with the name of `foo.db' being created with tables describing processor families and processor/os/compiler combinations. The database command `define-tables' is defined to call `define-tables' with its arguments. The database is also configured to print `Welcome' when the database is opened. The database is then closed and reopened. (require 'database-utilities) (define my-rdb (create-database "foo.db" 'alist-table)) (define-tables my-rdb '(*commands* ((name symbol)) ((parameters parameter-list) (procedure expression) (documentation string)) ((define-tables no-parameters no-parameter-names (lambda (rdb) (lambda specs (apply define-tables rdb specs))) "Create or Augment tables from list of specs") (*initialize* no-parameters no-parameter-names (lambda (rdb) (display "Welcome") (newline) rdb) "Print Welcome")))) ((my-rdb 'define-tables) '(processor-family ((family atom)) ((also-ran processor-family)) ((m68000 #f) (m68030 m68000) (i386 8086) (8086 #f) (powerpc #f))) '(platform ((name symbol)) ((processor processor-family) (os symbol) (compiler symbol)) ((aix powerpc aix -) (amiga-dice-c m68000 amiga dice-c) (amiga-aztec m68000 amiga aztec) (amiga-sas/c-5.10 m68000 amiga sas/c) (atari-st-gcc m68000 atari gcc) (atari-st-turbo-c m68000 atari turbo-c) (borland-c-3.1 8086 ms-dos borland-c) (djgpp i386 ms-dos gcc) (linux i386 linux gcc) (microsoft-c 8086 ms-dos microsoft-c) (os/2-emx i386 os/2 gcc) (turbo-c-2 8086 ms-dos turbo-c) (watcom-9.0 i386 ms-dos watcom)))) ((my-rdb 'close-database)) (set! my-rdb (open-database "foo.db" 'alist-table)) -| Welcome File: slib.info, Node: Database Reports, Next: Database Browser, Prev: Database Utilities, Up: Relational Database Database Reports ---------------- Code for generating database reports is in `report.scm'. After writing it using `format', I discovered that Common-Lisp `format' is not useable for this application because there is no mechanismm for truncating fields. `report.scm' needs to be rewritten using `printf'. - Procedure: create-report RDB DESTINATION REPORT-NAME TABLE - Procedure: create-report RDB DESTINATION REPORT-NAME The symbol REPORT-NAME must be primary key in the table named `*reports*' in the relational database RDB. DESTINATION is a port, string, or symbol. If DESTINATION is a: port The table is created as ascii text and written to that port. string The table is created as ascii text and written to the file named by DESTINATION. symbol DESTINATION is the primary key for a row in the table named *printers*. The report is prepared as follows: | | * `Format' (*note Format::.) is called with the `header' field | and the (list of) `column-names' of the table. | | * `Format' is called with the `reporter' field and (on | successive calls) each record in the natural order for the | table. A count is kept of the number of newlines output by | format. When the number of newlines to be output exceeds the | number of lines per page, the set of lines will be broken if | there are more than `minimum-break' left on this page and the | number of lines for this row is larger or equal to twice | `minimum-break'. | | * `Format' is called with the `footer' field and the (list of) | `column-names' of the table. The footer field should not | output a newline. | | * A new page is output. | | * This entire process repeats until all the rows are output. | | Each row in the table *reports* has the fields: The report name. default-table The table to report on if none is specified. header, footer A `format' string. At the beginning and end of each page respectively, `format' is called with this string and the (list of) | column-names of this table. | reporter A `format' string. For each row in the table, `format' is called | with this string and the row. | minimum-break The minimum number of lines into which the report lines for a row | can be broken. Use `0' if a row's lines should not be broken over | page boundaries. | Each row in the table *printers* has the fields: The printer name. print-procedure The procedure to call to actually print. | File: slib.info, Node: Database Browser, Prev: Database Reports, Up: Relational Database Database Browser ---------------- (require 'database-browse) - Procedure: browse DATABASE Prints the names of all the tables in DATABASE and sets browse's default to DATABASE. - Procedure: browse Prints the names of all the tables in the default database. - Procedure: browse TABLE-NAME For each record of the table named by the symbol TABLE-NAME, prints a line composed of all the field values. - Procedure: browse PATHNAME Opens the database named by the string PATHNAME, prints the names of all its tables, and sets browse's default to the database. - Procedure: browse DATABASE TABLE-NAME Sets browse's default to DATABASE and prints the records of the table named by the symbol TABLE-NAME. - Procedure: browse PATHNAME TABLE-NAME Opens the database named by the string PATHNAME and sets browse's default to it; `browse' prints the records of the table named by the symbol TABLE-NAME. File: slib.info, Node: Weight-Balanced Trees, Prev: Relational Database, Up: Database Packages Weight-Balanced Trees ===================== `(require 'wt-tree)' Balanced binary trees are a useful data structure for maintaining large sets of ordered objects or sets of associations whose keys are ordered. MIT Scheme has an comprehensive implementation of weight-balanced binary trees which has several advantages over the other data structures for large aggregates: * In addition to the usual element-level operations like insertion, deletion and lookup, there is a full complement of collection-level operations, like set intersection, set union and subset test, all of which are implemented with good orders of growth in time and space. This makes weight balanced trees ideal for rapid prototyping of functionally derived specifications. * An element in a tree may be indexed by its position under the ordering of the keys, and the ordinal position of an element may be determined, both with reasonable efficiency. * Operations to find and remove minimum element make weight balanced trees simple to use for priority queues. * The implementation is *functional* rather than *imperative*. This means that operations like `inserting' an association in a tree do not destroy the old tree, in much the same way that `(+ 1 x)' modifies neither the constant 1 nor the value bound to `x'. The trees are referentially transparent thus the programmer need not worry about copying the trees. Referential transparency allows space efficiency to be achieved by sharing subtrees. These features make weight-balanced trees suitable for a wide range of applications, especially those that require large numbers of sets or discrete maps. Applications that have a few global databases and/or concentrate on element-level operations like insertion and lookup are probably better off using hash-tables or red-black trees. The *size* of a tree is the number of associations that it contains. Weight balanced binary trees are balanced to keep the sizes of the subtrees of each node within a constant factor of each other. This ensures logarithmic times for single-path operations (like lookup and insertion). A weight balanced tree takes space that is proportional to the number of associations in the tree. For the current implementation, the constant of proportionality is six words per association. Weight balanced trees can be used as an implementation for either discrete sets or discrete maps (associations). Sets are implemented by ignoring the datum that is associated with the key. Under this scheme if an associations exists in the tree this indicates that the key of the association is a member of the set. Typically a value such as `()', `#t' or `#f' is associated with the key. Many operations can be viewed as computing a result that, depending on whether the tree arguments are thought of as sets or maps, is known by two different names. An example is `wt-tree/member?', which, when regarding the tree argument as a set, computes the set membership operation, but, when regarding the tree as a discrete map, `wt-tree/member?' is the predicate testing if the map is defined at an element in its domain. Most names in this package have been chosen based on interpreting the trees as sets, hence the name `wt-tree/member?' rather than `wt-tree/defined-at?'. The weight balanced tree implementation is a run-time-loadable option. To use weight balanced trees, execute (load-option 'wt-tree) once before calling any of the procedures defined here. * Menu: * Construction of Weight-Balanced Trees:: * Basic Operations on Weight-Balanced Trees:: * Advanced Operations on Weight-Balanced Trees:: * Indexing Operations on Weight-Balanced Trees:: File: slib.info, Node: Construction of Weight-Balanced Trees, Next: Basic Operations on Weight-Balanced Trees, Prev: Weight-Balanced Trees, Up: Weight-Balanced Trees Construction of Weight-Balanced Trees ------------------------------------- Binary trees require there to be a total order on the keys used to arrange the elements in the tree. Weight balanced trees are organized by *types*, where the type is an object encapsulating the ordering relation. Creating a tree is a two-stage process. First a tree type must be created from the predicate which gives the ordering. The tree type is then used for making trees, either empty or singleton trees or trees from other aggregate structures like association lists. Once created, a tree `knows' its type and the type is used to test compatibility between trees in operations taking two trees. Usually a small number of tree types are created at the beginning of a program and used many times throughout the program's execution. - procedure+: make-wt-tree-type KEY<? This procedure creates and returns a new tree type based on the ordering predicate KEY<?. KEY<? must be a total ordering, having the property that for all key values `a', `b' and `c': (key<? a a) => #f (and (key<? a b) (key<? b a)) => #f (if (and (key<? a b) (key<? b c)) (key<? a c) #t) => #t Two key values are assumed to be equal if neither is less than the other by KEY<?. Each call to `make-wt-tree-type' returns a distinct value, and trees are only compatible if their tree types are `eq?'. A consequence is that trees that are intended to be used in binary tree operations must all be created with a tree type originating from the same call to `make-wt-tree-type'. - variable+: number-wt-type A standard tree type for trees with numeric keys. `Number-wt-type' could have been defined by (define number-wt-type (make-wt-tree-type <)) - variable+: string-wt-type A standard tree type for trees with string keys. `String-wt-type' could have been defined by (define string-wt-type (make-wt-tree-type string<?)) - procedure+: make-wt-tree WT-TREE-TYPE This procedure creates and returns a newly allocated weight balanced tree. The tree is empty, i.e. it contains no associations. WT-TREE-TYPE is a weight balanced tree type obtained by calling `make-wt-tree-type'; the returned tree has this type. - procedure+: singleton-wt-tree WT-TREE-TYPE KEY DATUM This procedure creates and returns a newly allocated weight balanced tree. The tree contains a single association, that of DATUM with KEY. WT-TREE-TYPE is a weight balanced tree type obtained by calling `make-wt-tree-type'; the returned tree has this type. - procedure+: alist->wt-tree TREE-TYPE ALIST Returns a newly allocated weight-balanced tree that contains the same associations as ALIST. This procedure is equivalent to: (lambda (type alist) (let ((tree (make-wt-tree type))) (for-each (lambda (association) (wt-tree/add! tree (car association) (cdr association))) alist) tree)) File: slib.info, Node: Basic Operations on Weight-Balanced Trees, Next: Advanced Operations on Weight-Balanced Trees, Prev: Construction of Weight-Balanced Trees, Up: Weight-Balanced Trees Basic Operations on Weight-Balanced Trees ----------------------------------------- This section describes the basic tree operations on weight balanced trees. These operations are the usual tree operations for insertion, deletion and lookup, some predicates and a procedure for determining the number of associations in a tree. - procedure+: wt-tree? OBJECT Returns `#t' if OBJECT is a weight-balanced tree, otherwise returns `#f'. - procedure+: wt-tree/empty? WT-TREE Returns `#t' if WT-TREE contains no associations, otherwise returns `#f'. - procedure+: wt-tree/size WT-TREE Returns the number of associations in WT-TREE, an exact non-negative integer. This operation takes constant time. - procedure+: wt-tree/add WT-TREE KEY DATUM Returns a new tree containing all the associations in WT-TREE and the association of DATUM with KEY. If WT-TREE already had an association for KEY, the new association overrides the old. The average and worst-case times required by this operation are proportional to the logarithm of the number of associations in WT-TREE. - procedure+: wt-tree/add! WT-TREE KEY DATUM Associates DATUM with KEY in WT-TREE and returns an unspecified value. If WT-TREE already has an association for KEY, that association is replaced. The average and worst-case times required by this operation are proportional to the logarithm of the number of associations in WT-TREE. - procedure+: wt-tree/member? KEY WT-TREE Returns `#t' if WT-TREE contains an association for KEY, otherwise returns `#f'. The average and worst-case times required by this operation are proportional to the logarithm of the number of associations in WT-TREE. - procedure+: wt-tree/lookup WT-TREE KEY DEFAULT Returns the datum associated with KEY in WT-TREE. If WT-TREE doesn't contain an association for KEY, DEFAULT is returned. The average and worst-case times required by this operation are proportional to the logarithm of the number of associations in WT-TREE. - procedure+: wt-tree/delete WT-TREE KEY Returns a new tree containing all the associations in WT-TREE, except that if WT-TREE contains an association for KEY, it is removed from the result. The average and worst-case times required by this operation are proportional to the logarithm of the number of associations in WT-TREE. - procedure+: wt-tree/delete! WT-TREE KEY If WT-TREE contains an association for KEY the association is removed. Returns an unspecified value. The average and worst-case times required by this operation are proportional to the logarithm of the number of associations in WT-TREE. File: slib.info, Node: Advanced Operations on Weight-Balanced Trees, Next: Indexing Operations on Weight-Balanced Trees, Prev: Basic Operations on Weight-Balanced Trees, Up: Weight-Balanced Trees Advanced Operations on Weight-Balanced Trees -------------------------------------------- In the following the *size* of a tree is the number of associations that the tree contains, and a *smaller* tree contains fewer associations. - procedure+: wt-tree/split< WT-TREE BOUND Returns a new tree containing all and only the associations in WT-TREE which have a key that is less than BOUND in the ordering relation of the tree type of WT-TREE. The average and worst-case times required by this operation are proportional to the logarithm of the size of WT-TREE. - procedure+: wt-tree/split> WT-TREE BOUND Returns a new tree containing all and only the associations in WT-TREE which have a key that is greater than BOUND in the ordering relation of the tree type of WT-TREE. The average and worst-case times required by this operation are proportional to the logarithm of size of WT-TREE. - procedure+: wt-tree/union WT-TREE-1 WT-TREE-2 Returns a new tree containing all the associations from both trees. This operation is asymmetric: when both trees have an association for the same key, the returned tree associates the datum from WT-TREE-2 with the key. Thus if the trees are viewed as discrete maps then `wt-tree/union' computes the map override of WT-TREE-1 by WT-TREE-2. If the trees are viewed as sets the result is the set union of the arguments. The worst-case time required by this operation is proportional to the sum of the sizes of both trees. If the minimum key of one tree is greater than the maximum key of the other tree then the time required is at worst proportional to the logarithm of the size of the larger tree. - procedure+: wt-tree/intersection WT-TREE-1 WT-TREE-2 Returns a new tree containing all and only those associations from WT-TREE-1 which have keys appearing as the key of an association in WT-TREE-2. Thus the associated data in the result are those from WT-TREE-1. If the trees are being used as sets the result is the set intersection of the arguments. As a discrete map operation, `wt-tree/intersection' computes the domain restriction of WT-TREE-1 to (the domain of) WT-TREE-2. The time required by this operation is never worse that proportional to the sum of the sizes of the trees. - procedure+: wt-tree/difference WT-TREE-1 WT-TREE-2 Returns a new tree containing all and only those associations from WT-TREE-1 which have keys that *do not* appear as the key of an association in WT-TREE-2. If the trees are viewed as sets the result is the asymmetric set difference of the arguments. As a discrete map operation, it computes the domain restriction of WT-TREE-1 to the complement of (the domain of) WT-TREE-2. The time required by this operation is never worse that proportional to the sum of the sizes of the trees. - procedure+: wt-tree/subset? WT-TREE-1 WT-TREE-2 Returns `#t' iff the key of each association in WT-TREE-1 is the key of some association in WT-TREE-2, otherwise returns `#f'. Viewed as a set operation, `wt-tree/subset?' is the improper subset predicate. A proper subset predicate can be constructed: (define (proper-subset? s1 s2) (and (wt-tree/subset? s1 s2) (< (wt-tree/size s1) (wt-tree/size s2)))) As a discrete map operation, `wt-tree/subset?' is the subset test on the domain(s) of the map(s). In the worst-case the time required by this operation is proportional to the size of WT-TREE-1. - procedure+: wt-tree/set-equal? WT-TREE-1 WT-TREE-2 Returns `#t' iff for every association in WT-TREE-1 there is an association in WT-TREE-2 that has the same key, and *vice versa*. Viewing the arguments as sets `wt-tree/set-equal?' is the set equality predicate. As a map operation it determines if two maps are defined on the same domain. This procedure is equivalent to (lambda (wt-tree-1 wt-tree-2) (and (wt-tree/subset? wt-tree-1 wt-tree-2 (wt-tree/subset? wt-tree-2 wt-tree-1))) In the worst-case the time required by this operation is proportional to the size of the smaller tree. - procedure+: wt-tree/fold COMBINER INITIAL WT-TREE This procedure reduces WT-TREE by combining all the associations, using an reverse in-order traversal, so the associations are visited in reverse order. COMBINER is a procedure of three arguments: a key, a datum and the accumulated result so far. Provided COMBINER takes time bounded by a constant, `wt-tree/fold' takes time proportional to the size of WT-TREE. A sorted association list can be derived simply: (wt-tree/fold (lambda (key datum list) (cons (cons key datum) list)) '() WT-TREE)) The data in the associations can be summed like this: (wt-tree/fold (lambda (key datum sum) (+ sum datum)) 0 WT-TREE) - procedure+: wt-tree/for-each ACTION WT-TREE This procedure traverses the tree in-order, applying ACTION to each association. The associations are processed in increasing order of their keys. ACTION is a procedure of two arguments which take the key and datum respectively of the association. Provided ACTION takes time bounded by a constant, `wt-tree/for-each' takes time proportional to in the size of WT-TREE. The example prints the tree: (wt-tree/for-each (lambda (key value) (display (list key value))) WT-TREE)) File: slib.info, Node: Indexing Operations on Weight-Balanced Trees, Prev: Advanced Operations on Weight-Balanced Trees, Up: Weight-Balanced Trees Indexing Operations on Weight-Balanced Trees -------------------------------------------- Weight balanced trees support operations that view the tree as sorted sequence of associations. Elements of the sequence can be accessed by position, and the position of an element in the sequence can be determined, both in logarthmic time. - procedure+: wt-tree/index WT-TREE INDEX - procedure+: wt-tree/index-datum WT-TREE INDEX - procedure+: wt-tree/index-pair WT-TREE INDEX Returns the 0-based INDEXth association of WT-TREE in the sorted sequence under the tree's ordering relation on the keys. `wt-tree/index' returns the INDEXth key, `wt-tree/index-datum' returns the datum associated with the INDEXth key and `wt-tree/index-pair' returns a new pair `(KEY . DATUM)' which is the `cons' of the INDEXth key and its datum. The average and worst-case times required by this operation are proportional to the logarithm of the number of associations in the tree. These operations signal an error if the tree is empty, if INDEX`<0', or if INDEX is greater than or equal to the number of associations in the tree. Indexing can be used to find the median and maximum keys in the tree as follows: median: (wt-tree/index WT-TREE (quotient (wt-tree/size WT-TREE) 2)) maximum: (wt-tree/index WT-TREE (-1+ (wt-tree/size WT-TREE))) - procedure+: wt-tree/rank WT-TREE KEY Determines the 0-based position of KEY in the sorted sequence of the keys under the tree's ordering relation, or `#f' if the tree has no association with for KEY. This procedure returns either an exact non-negative integer or `#f'. The average and worst-case times required by this operation are proportional to the logarithm of the number of associations in the tree. - procedure+: wt-tree/min WT-TREE - procedure+: wt-tree/min-datum WT-TREE - procedure+: wt-tree/min-pair WT-TREE Returns the association of WT-TREE that has the least key under the tree's ordering relation. `wt-tree/min' returns the least key, `wt-tree/min-datum' returns the datum associated with the least key and `wt-tree/min-pair' returns a new pair `(key . datum)' which is the `cons' of the minimum key and its datum. The average and worst-case times required by this operation are proportional to the logarithm of the number of associations in the tree. These operations signal an error if the tree is empty. They could be written (define (wt-tree/min tree) (wt-tree/index tree 0)) (define (wt-tree/min-datum tree) (wt-tree/index-datum tree 0)) (define (wt-tree/min-pair tree) (wt-tree/index-pair tree 0)) - procedure+: wt-tree/delete-min WT-TREE Returns a new tree containing all of the associations in WT-TREE except the association with the least key under the WT-TREE's ordering relation. An error is signalled if the tree is empty. The average and worst-case times required by this operation are proportional to the logarithm of the number of associations in the tree. This operation is equivalent to (wt-tree/delete WT-TREE (wt-tree/min WT-TREE)) - procedure+: wt-tree/delete-min! WT-TREE Removes the association with the least key under the WT-TREE's ordering relation. An error is signalled if the tree is empty. The average and worst-case times required by this operation are proportional to the logarithm of the number of associations in the tree. This operation is equivalent to (wt-tree/delete! WT-TREE (wt-tree/min WT-TREE)) File: slib.info, Node: Other Packages, Next: About SLIB, Prev: Database Packages, Up: Top Other Packages ************** * Menu: * Data Structures:: Various data structures. * Procedures:: Miscellaneous utility procedures. * Standards Support:: Support for Scheme Standards. * Session Support:: REPL and Debugging. * Extra-SLIB Packages:: File: slib.info, Node: Data Structures, Next: Procedures, Prev: Other Packages, Up: Other Packages Data Structures =============== * Menu: * Arrays:: 'array * Array Mapping:: 'array-for-each * Association Lists:: 'alist * Byte:: 'byte * Collections:: 'collect * Dynamic Data Type:: 'dynamic * Hash Tables:: 'hash-table * Hashing:: 'hash, 'sierpinski, 'soundex * Object:: 'object | * Priority Queues:: 'priority-queue * Queues:: 'queue * Records:: 'record * Structures:: 'struct, 'structure File: slib.info, Node: Arrays, Next: Array Mapping, Prev: Data Structures, Up: Data Structures Arrays ------ `(require 'array)' - Function: array? OBJ Returns `#t' if the OBJ is an array, and `#f' if not. - Function: make-array INITIAL-VALUE BOUND1 BOUND2 ... Creates and returns an array that has as many dimensins as there are BOUNDs and fills it with INITIAL-VALUE. When constructing an array, BOUND is either an inclusive range of indices expressed as a two element list, or an upper bound expressed as a single integer. So (make-array 'foo 3 3) == (make-array 'foo '(0 2) '(0 2)) - Function: make-shared-array ARRAY MAPPER BOUND1 BOUND2 ... `make-shared-array' can be used to create shared subarrays of other arrays. The MAPPER is a function that translates coordinates in the new array into coordinates in the old array. A MAPPER must be linear, and its range must stay within the bounds of the old array, but it can be otherwise arbitrary. A simple example: (define fred (make-array #f 8 8)) (define freds-diagonal (make-shared-array fred (lambda (i) (list i i)) 8)) (array-set! freds-diagonal 'foo 3) (array-ref fred 3 3) => FOO (define freds-center (make-shared-array fred (lambda (i j) (list (+ 3 i) (+ 3 j))) 2 2)) (array-ref freds-center 0 0) => FOO - Function: array-rank OBJ Returns the number of dimensions of OBJ. If OBJ is not an array, 0 is returned. - Function: array-shape ARRAY `array-shape' returns a list of inclusive bounds. So: (array-shape (make-array 'foo 3 5)) => ((0 2) (0 4)) - Function: array-dimensions ARRAY `array-dimensions' is similar to `array-shape' but replaces elements with a 0 minimum with one greater than the maximum. So: (array-dimensions (make-array 'foo 3 5)) => (3 5) - Procedure: array-in-bounds? ARRAY INDEX1 INDEX2 ... Returns `#t' if its arguments would be acceptable to `array-ref'. - Function: array-ref ARRAY INDEX1 INDEX2 ... Returns the element at the `(INDEX1, INDEX2)' element in ARRAY. - Procedure: array-set! ARRAY NEW-VALUE INDEX1 INDEX2 ... - Function: array-1d-ref ARRAY INDEX - Function: array-2d-ref ARRAY INDEX1 INDEX2 - Function: array-3d-ref ARRAY INDEX1 INDEX2 INDEX3 - Procedure: array-1d-set! ARRAY NEW-VALUE INDEX - Procedure: array-2d-set! ARRAY NEW-VALUE INDEX1 INDEX2 - Procedure: array-3d-set! ARRAY NEW-VALUE INDEX1 INDEX2 INDEX3 The functions are just fast versions of `array-ref' and `array-set!' that take a fixed number of arguments, and perform no bounds checking. If you comment out the bounds checking code, this is about as efficient as you could ask for without help from the compiler. An exercise left to the reader: implement the rest of APL. File: slib.info, Node: Array Mapping, Next: Association Lists, Prev: Arrays, Up: Data Structures Array Mapping ------------- `(require 'array-for-each)' - Function: array-map! ARRAY0 PROC ARRAY1 ... ARRAY1, ... must have the same number of dimensions as ARRAY0 and have a range for each index which includes the range for the corresponding index in ARRAY0. PROC is applied to each tuple of elements of ARRAY1 ... and the result is stored as the corresponding element in ARRAY0. The value returned is unspecified. The order of application is unspecified. - Function: array-for-each PROC ARRAY0 ... PROC is applied to each tuple of elements of ARRAY0 ... in row-major order. The value returned is unspecified. - Function: array-indexes ARRAY Returns an array of lists of indexes for ARRAY such that, if LI is a list of indexes for which ARRAY is defined, (equal? LI (apply array-ref (array-indexes ARRAY) LI)). - Function: array-index-map! ARRAY PROC applies PROC to the indices of each element of ARRAY in turn, storing the result in the corresponding element. The value returned and the order of application are unspecified. One can implement ARRAY-INDEXES as (define (array-indexes array) (let ((ra (apply make-array #f (array-shape array)))) (array-index-map! ra (lambda x x)) ra)) Another example: (define (apl:index-generator n) (let ((v (make-uniform-vector n 1))) (array-index-map! v (lambda (i) i)) v)) - Function: array-copy! SOURCE DESTINATION Copies every element from vector or array SOURCE to the corresponding element of DESTINATION. DESTINATION must have the same rank as SOURCE, and be at least as large in each dimension. The order of copying is unspecified. File: slib.info, Node: Association Lists, Next: Byte, Prev: Array Mapping, Up: Data Structures Association Lists ----------------- `(require 'alist)' Alist functions provide utilities for treating a list of key-value pairs as an associative database. These functions take an equality predicate, PRED, as an argument. This predicate should be repeatable, symmetric, and transitive. Alist functions can be used with a secondary index method such as hash tables for improved performance. - Function: predicate->asso PRED Returns an "association function" (like `assq', `assv', or `assoc') corresponding to PRED. The returned function returns a key-value pair whose key is `pred'-equal to its first argument or `#f' if no key in the alist is PRED-equal to the first argument. - Function: alist-inquirer PRED Returns a procedure of 2 arguments, ALIST and KEY, which returns the value associated with KEY in ALIST or `#f' if KEY does not appear in ALIST. - Function: alist-associator PRED Returns a procedure of 3 arguments, ALIST, KEY, and VALUE, which returns an alist with KEY and VALUE associated. Any previous value associated with KEY will be lost. This returned procedure may or may not have side effects on its ALIST argument. An example of correct usage is: (define put (alist-associator string-ci=?)) (define alist '()) (set! alist (put alist "Foo" 9)) - Function: alist-remover PRED Returns a procedure of 2 arguments, ALIST and KEY, which returns an alist with an association whose KEY is key removed. This returned procedure may or may not have side effects on its ALIST argument. An example of correct usage is: (define rem (alist-remover string-ci=?)) (set! alist (rem alist "foo")) - Function: alist-map PROC ALIST Returns a new association list formed by mapping PROC over the keys and values of ALIST. PROC must be a function of 2 arguments which returns the new value part. - Function: alist-for-each PROC ALIST Applies PROC to each pair of keys and values of ALIST. PROC must be a function of 2 arguments. The returned value is unspecified. File: slib.info, Node: Byte, Next: Collections, Prev: Association Lists, Up: Data Structures `(require 'byte)' Some algorithms are expressed in terms of arrays of small integers. Using Scheme strings to implement these arrays is not portable vis-a-vis the correspondence between integers and characters and non-ascii character sets. These functions abstract the notion of a "byte". - Function: byte-ref BYTES K K must be a valid index of BYTES. `byte-ref' returns byte K of BYTES using zero-origin indexing. - Procedure: byte-set! BYTES K BYTE K must be a valid index of BYTES%, and BYTE must be a small integer. `Byte-set!' stores BYTE in element K of BYTES and returns an unspecified value. - Function: make-bytes K - Function: make-bytes K BYTE `Make-bytes' returns a newly allocated byte-array of length K. If BYTE is given, then all elements of the byte-array are initialized to BYTE, otherwise the contents of the byte-array are unspecified. - Function: bytes-length BYTES `bytes-length' returns length of byte-array BYTES. - Function: write-byte BYTE - Function: write-byte BYTE PORT Writes the byte BYTE (not an external representation of the byte) to the given PORT and returns an unspecified value. The PORT argument may be omitted, in which case it defaults to the value returned by `current-output-port'. - Function: read-byte - Function: read-byte PORT Returns the next byte available from the input PORT, updating the PORT to point to the following byte. If no more bytes are available, an end of file object is returned. PORT may be omitted, in which case it defaults to the value returned by `current-input-port'. - Function: bytes BYTE ... Returns a newly allocated byte-array composed of the arguments. - Function: bytes->list BYTES - Function: list->bytes BYTES `Bytes->list' returns a newly allocated list of the bytes that make up the given byte-array. `List->bytes' returns a newly allocated byte-array formed from the small integers in the list BYTES. `Bytes->list' and `list->bytes' are inverses so far as `equal?' is concerned. File: slib.info, Node: Collections, Next: Dynamic Data Type, Prev: Byte, Up: Data Structures Collections ----------- `(require 'collect)' Routines for managing collections. Collections are aggregate data structures supporting iteration over their elements, similar to the Dylan(TM) language, but with a different interface. They have "elements" indexed by corresponding "keys", although the keys may be implicit (as with lists). New types of collections may be defined as YASOS objects (*Note Yasos::). They must support the following operations: * `(collection? SELF)' (always returns `#t'); * `(size SELF)' returns the number of elements in the collection; * `(print SELF PORT)' is a specialized print operation for the collection which prints a suitable representation on the given PORT or returns it as a string if PORT is `#t'; * `(gen-elts SELF)' returns a thunk which on successive invocations yields elements of SELF in order or gives an error if it is invoked more than `(size SELF)' times; * `(gen-keys SELF)' is like `gen-elts', but yields the collection's keys in order. They might support specialized `for-each-key' and `for-each-elt' operations. - Function: collection? OBJ A predicate, true initially of lists, vectors and strings. New sorts of collections must answer `#t' to `collection?'. - Procedure: map-elts PROC . COLLECTIONS - Procedure: do-elts PROC . COLLECTIONS PROC is a procedure taking as many arguments as there are COLLECTIONS (at least one). The COLLECTIONS are iterated over in their natural order and PROC is applied to the elements yielded by each iteration in turn. The order in which the arguments are supplied corresponds to te order in which the COLLECTIONS appear. `do-elts' is used when only side-effects of PROC are of interest and its return value is unspecified. `map-elts' returns a collection (actually a vector) of the results of the applications of PROC. Example: (map-elts + (list 1 2 3) (vector 1 2 3)) => #(2 4 6) - Procedure: map-keys PROC . COLLECTIONS - Procedure: do-keys PROC . COLLECTIONS These are analogous to `map-elts' and `do-elts', but each iteration is over the COLLECTIONS' *keys* rather than their elements. Example: (map-keys + (list 1 2 3) (vector 1 2 3)) => #(0 2 4) - Procedure: for-each-key COLLECTION PROC - Procedure: for-each-elt COLLECTION PROC These are like `do-keys' and `do-elts' but only for a single collection; they are potentially more efficient. - Function: reduce PROC SEED . COLLECTIONS A generalization of the list-based `comlist:reduce-init' (*Note Lists as sequences::) to collections which will shadow the list-based version if `(require 'collect)' follows `(require 'common-list-functions)' (*Note Common List Functions::). Examples: (reduce + 0 (vector 1 2 3)) => 6 (reduce union '() '((a b c) (b c d) (d a))) => (c b d a). - Function: any? PRED . COLLECTIONS A generalization of the list-based `some' (*Note Lists as sequences::) to collections. Example: (any? odd? (list 2 3 4 5)) => #t - Function: every? PRED . COLLECTIONS A generalization of the list-based `every' (*Note Lists as sequences::) to collections. Example: (every? collection? '((1 2) #(1 2))) => #t - Function: empty? COLLECTION Returns `#t' iff there are no elements in COLLECTION. `(empty? COLLECTION) == (zero? (size COLLECTION))' - Function: size COLLECTION Returns the number of elements in COLLECTION. - Function: Setter LIST-REF See *Note Setters:: for a definition of "setter". N.B. `(setter list-ref)' doesn't work properly for element 0 of a list. Here is a sample collection: `simple-table' which is also a `table'. (define-predicate TABLE?) (define-operation (LOOKUP table key failure-object)) (define-operation (ASSOCIATE! table key value)) ;; returns key (define-operation (REMOVE! table key)) ;; returns value (define (MAKE-SIMPLE-TABLE) (let ( (table (list)) ) (object ;; table behaviors ((TABLE? self) #t) ((SIZE self) (size table)) ((PRINT self port) (format port "#<SIMPLE-TABLE>")) ((LOOKUP self key failure-object) (cond ((assq key table) => cdr) (else failure-object) )) ((ASSOCIATE! self key value) (cond ((assq key table) => (lambda (bucket) (set-cdr! bucket value) key)) (else (set! table (cons (cons key value) table)) key) )) ((REMOVE! self key);; returns old value (cond ((null? table) (slib:error "TABLE:REMOVE! Key not found: " key)) ((eq? key (caar table)) (let ( (value (cdar table)) ) (set! table (cdr table)) value) ) (else (let loop ( (last table) (this (cdr table)) ) (cond ((null? this) (slib:error "TABLE:REMOVE! Key not found: " key)) ((eq? key (caar this)) (let ( (value (cdar this)) ) (set-cdr! last (cdr this)) value) ) (else (loop (cdr last) (cdr this))) ) ) ) )) ;; collection behaviors ((COLLECTION? self) #t) ((GEN-KEYS self) (collect:list-gen-elts (map car table))) ((GEN-ELTS self) (collect:list-gen-elts (map cdr table))) ((FOR-EACH-KEY self proc) (for-each (lambda (bucket) (proc (car bucket))) table) ) ((FOR-EACH-ELT self proc) (for-each (lambda (bucket) (proc (cdr bucket))) table) ) ) ) ) File: slib.info, Node: Dynamic Data Type, Next: Hash Tables, Prev: Collections, Up: Data Structures Dynamic Data Type ----------------- `(require 'dynamic)' - Function: make-dynamic OBJ Create and returns a new "dynamic" whose global value is OBJ. - Function: dynamic? OBJ Returns true if and only if OBJ is a dynamic. No object satisfying `dynamic?' satisfies any of the other standard type predicates. - Function: dynamic-ref DYN Return the value of the given dynamic in the current dynamic environment. - Procedure: dynamic-set! DYN OBJ Change the value of the given dynamic to OBJ in the current dynamic environment. The returned value is unspecified. - Function: call-with-dynamic-binding DYN OBJ THUNK Invoke and return the value of the given thunk in a new, nested dynamic environment in which the given dynamic has been bound to a new location whose initial contents are the value OBJ. This dynamic environment has precisely the same extent as the invocation of the thunk and is thus captured by continuations created within that invocation and re-established by those continuations when they are invoked. The `dynamic-bind' macro is not implemented. File: slib.info, Node: Hash Tables, Next: Hashing, Prev: Dynamic Data Type, Up: Data Structures Hash Tables ----------- `(require 'hash-table)' - Function: predicate->hash PRED Returns a hash function (like `hashq', `hashv', or `hash') corresponding to the equality predicate PRED. PRED should be `eq?', `eqv?', `equal?', `=', `char=?', `char-ci=?', `string=?', or `string-ci=?'. A hash table is a vector of association lists. - Function: make-hash-table K Returns a vector of K empty (association) lists. Hash table functions provide utilities for an associative database. These functions take an equality predicate, PRED, as an argument. PRED should be `eq?', `eqv?', `equal?', `=', `char=?', `char-ci=?', `string=?', or `string-ci=?'. - Function: predicate->hash-asso PRED Returns a hash association function of 2 arguments, KEY and HASHTAB, corresponding to PRED. The returned function returns a key-value pair whose key is PRED-equal to its first argument or `#f' if no key in HASHTAB is PRED-equal to the first argument. - Function: hash-inquirer PRED Returns a procedure of 3 arguments, `hashtab' and `key', which returns the value associated with `key' in `hashtab' or `#f' if key does not appear in `hashtab'. - Function: hash-associator PRED Returns a procedure of 3 arguments, HASHTAB, KEY, and VALUE, which modifies HASHTAB so that KEY and VALUE associated. Any previous value associated with KEY will be lost. - Function: hash-remover PRED Returns a procedure of 2 arguments, HASHTAB and KEY, which modifies HASHTAB so that the association whose key is KEY is removed. - Function: hash-map PROC HASH-TABLE Returns a new hash table formed by mapping PROC over the keys and values of HASH-TABLE. PROC must be a function of 2 arguments which returns the new value part. - Function: hash-for-each PROC HASH-TABLE Applies PROC to each pair of keys and values of HASH-TABLE. PROC must be a function of 2 arguments. The returned value is unspecified. File: slib.info, Node: Hashing, Next: Object, Prev: Hash Tables, Up: Data Structures | Hashing ------- `(require 'hash)' These hashing functions are for use in quickly classifying objects. Hash tables use these functions. - Function: hashq OBJ K - Function: hashv OBJ K - Function: hash OBJ K Returns an exact non-negative integer less than K. For each non-negative integer less than K there are arguments OBJ for which the hashing functions applied to OBJ and K returns that integer. For `hashq', `(eq? obj1 obj2)' implies `(= (hashq obj1 k) (hashq obj2))'. For `hashv', `(eqv? obj1 obj2)' implies `(= (hashv obj1 k) (hashv obj2))'. For `hash', `(equal? obj1 obj2)' implies `(= (hash obj1 k) (hash obj2))'. `hash', `hashv', and `hashq' return in time bounded by a constant. Notice that items having the same `hash' implies the items have the same `hashv' implies the items have the same `hashq'. `(require 'sierpinski)' - Function: make-sierpinski-indexer MAX-COORDINATE Returns a procedure (eg hash-function) of 2 numeric arguments which preserves *nearness* in its mapping from NxN to N. MAX-COORDINATE is the maximum coordinate (a positive integer) of a population of points. The returned procedures is a function that takes the x and y coordinates of a point, (non-negative integers) and returns an integer corresponding to the relative position of that point along a Sierpinski curve. (You can think of this as computing a (pseudo-) inverse of the Sierpinski spacefilling curve.) Example use: Make an indexer (hash-function) for integer points lying in square of integer grid points [0,99]x[0,99]: (define space-key (make-sierpinski-indexer 100)) Now let's compute the index of some points: (space-key 24 78) => 9206 (space-key 23 80) => 9172 Note that locations (24, 78) and (23, 80) are near in index and therefore, because the Sierpinski spacefilling curve is continuous, we know they must also be near in the plane. Nearness in the plane does not, however, necessarily correspond to nearness in index, although it *tends* to be so. Example applications: * Sort points by Sierpinski index to get heuristic solution to *travelling salesman problem*. For details of performance, see L. Platzman and J. Bartholdi, "Spacefilling curves and the Euclidean travelling salesman problem", JACM 36(4):719-737 (October 1989) and references therein. * Use Sierpinski index as key by which to store 2-dimensional data in a 1-dimensional data structure (such as a table). Then locations that are near each other in 2-d space will tend to be near each other in 1-d data structure; and locations that are near in 1-d data structure will be near in 2-d space. This can significantly speed retrieval from secondary storage because contiguous regions in the plane will tend to correspond to contiguous regions in secondary storage. (This is a standard technique for managing CAD/CAM or geographic data.) `(require 'soundex)' - Function: soundex NAME Computes the *soundex* hash of NAME. Returns a string of an initial letter and up to three digits between 0 and 6. Soundex supposedly has the property that names that sound similar in normal English pronunciation tend to map to the same key. Soundex was a classic algorithm used for manual filing of personal records before the advent of computers. It performs adequately for English names but has trouble with other nationalities. See Knuth, Vol. 3 `Sorting and searching', pp 391-2 To manage unusual inputs, `soundex' omits all non-alphabetic characters. Consequently, in this implementation: (soundex <string of blanks>) => "" (soundex "") => "" Examples from Knuth: (map soundex '("Euler" "Gauss" "Hilbert" "Knuth" "Lloyd" "Lukasiewicz")) => ("E460" "G200" "H416" "K530" "L300" "L222") (map soundex '("Ellery" "Ghosh" "Heilbronn" "Kant" "Ladd" "Lissajous")) => ("E460" "G200" "H416" "K530" "L300" "L222") Some cases in which the algorithm fails (Knuth): (map soundex '("Rogers" "Rodgers")) => ("R262" "R326") (map soundex '("Sinclair" "St. Clair")) => ("S524" "S324") (map soundex '("Tchebysheff" "Chebyshev")) => ("T212" "C121") File: slib.info, Node: Object, Next: Priority Queues, Prev: Hashing, Up: Data Structures | Macroless Object System | ----------------------- | | `(require 'object)' | | This is the Macroless Object System written by Wade Humeniuk | (whumeniu@datap.ca). Conceptual Tributes: *Note Yasos::, MacScheme's | %object, CLOS, Lack of R4RS macros. | | Concepts | -------- | | OBJECT | An object is an ordered association-list (by `eq?') of methods | (procedures). Methods can be added (`make-method!'), deleted | (`unmake-method!') and retrieved (`get-method'). Objects may | inherit methods from other objects. The object binds to the | environment it was created in, allowing closures to be used to | hide private procedures and data. | | GENERIC-METHOD | A generic-method associates (in terms of `eq?') object's method. | This allows scheme function style to be used for objects. The | calling scheme for using a generic method is `(generic-method | object param1 param2 ...)'. | | METHOD | A method is a procedure that exists in the object. To use a method | get-method must be called to look-up the method. Generic methods | implement the get-method functionality. Methods may be added to an | object associated with any scheme obj in terms of eq? | | GENERIC-PREDICATE | A generic method that returns a boolean value for any scheme obj. | | PREDICATE | A object's method asscociated with a generic-predicate. Returns | `#t'. | | Procedures | ---------- | | - Function: make-object ANCESTOR ... | Returns an object. Current object implementation is a tagged | vector. ANCESTORs are optional and must be objects in terms of | object?. ANCESTORs methods are included in the object. Multiple | ANCESTORs might associate the same generic-method with a method. | In this case the method of the ANCESTOR first appearing in the | list is the one returned by `get-method'. | | - Function: object? OBJ | Returns boolean value whether OBJ was created by make-object. | | - Function: make-generic-method EXCEPTION-PROCEDURE | Returns a procedure which be associated with an object's methods. | If EXCEPTION-PROCEDURE is specified then it is used to process | non-objects. | | - Function: make-generic-predicate | Returns a boolean procedure for any scheme object. | | - Function: make-method! OBJECT GENERIC-METHOD METHOD | Associates METHOD to the GENERIC-METHOD in the object. The METHOD | overrides any previous association with the GENERIC-METHOD within | the object. Using `unmake-method!' will restore the object's | previous association with the GENERIC-METHOD. METHOD must be a | procedure. | | - Function: make-predicate! OBJECT GENERIC-PRECIATE | Makes a predicate method associated with the GENERIC-PREDICATE. | | - Function: unmake-method! OBJECT GENERIC-METHOD | Removes an object's association with a GENERIC-METHOD . | | - Function: get-method OBJECT GENERIC-METHOD | Returns the object's method associated (if any) with the | GENERIC-METHOD. If no associated method exists an error is | flagged. | | Examples | -------- | | (require 'object) | | (define instantiate (make-generic-method)) | | (define (make-instance-object . ancestors) | (define self (apply make-object | (map (lambda (obj) (instantiate obj)) ancestors))) | (make-method! self instantiate (lambda (self) self)) | self) | | (define who (make-generic-method)) | (define imigrate! (make-generic-method)) | (define emigrate! (make-generic-method)) | (define describe (make-generic-method)) | (define name (make-generic-method)) | (define address (make-generic-method)) | (define members (make-generic-method)) | | (define society | (let () | (define self (make-instance-object)) | (define population '()) | (make-method! self imigrate! | (lambda (new-person) | (if (not (eq? new-person self)) | (set! population (cons new-person population))))) (make-method! self emigrate! | (lambda (person) | (if (not (eq? person self)) | (set! population | (comlist:remove-if (lambda (member) | (eq? member person)) | population))))) | (make-method! self describe | (lambda (self) | (map (lambda (person) (describe person)) population))) (make-method! self who | (lambda (self) (map (lambda (person) (name person)) | population))) | (make-method! self members (lambda (self) population)) | self)) | | (define (make-person %name %address) | (define self (make-instance-object society)) | (make-method! self name (lambda (self) %name)) | (make-method! self address (lambda (self) %address)) | (make-method! self who (lambda (self) (name self))) | (make-method! self instantiate | (lambda (self) | (make-person (string-append (name self) "-son-of") | %address))) | (make-method! self describe | (lambda (self) (list (name self) (address self)))) | (imigrate! self) | self) | | Inverter Documentation | ...................... | | Inheritance: | <inverter>::(<number> <description>) | Generic-methods | <inverter>::value => <number>::value | <inverter>::set-value! => <number>::set-value! | <inverter>::describe => <description>::describe | <inverter>::help | <inverter>::invert | <inverter>::inverter? | | Number Documention | .................. | | Inheritance | <number>::() | Slots | <number>::<x> | Generic Methods | <number>::value | <number>::set-value! | | Inverter code | ............. | | (require 'object) | | (define value (make-generic-method (lambda (val) val))) | (define set-value! (make-generic-method)) | (define invert (make-generic-method | (lambda (val) | (if (number? val) | (/ 1 val) | (error "Method not supported:" val))))) | (define noop (make-generic-method)) | (define inverter? (make-generic-predicate)) | (define describe (make-generic-method)) | (define help (make-generic-method)) | | (define (make-number x) | (define self (make-object)) | (make-method! self value (lambda (this) x)) | (make-method! self set-value! | (lambda (this new-value) (set! x new-value))) | self) | | (define (make-description str) | (define self (make-object)) | (make-method! self describe (lambda (this) str)) | (make-method! self help (lambda (this) "Help not available")) | self) | | (define (make-inverter) | (let* ((self (make-object | (make-number 1) | (make-description "A number which can be inverted"))) | (<value> (get-method self value))) | (make-method! self invert (lambda (self) (/ 1 (<value> self)))) | (make-predicate! self inverter?) | (unmake-method! self help) | (make-method! self help | (lambda (self) | (display "Inverter Methods:") (newline) | (display " (value inverter) ==> n") (newline))) | self)) | | ;;;; Try it out | | (define invert! (make-generic-method)) | | (define x (make-inverter)) | | (make-method! x invert! (lambda (x) (set-value! x (/ 1 (value x))))) | | (value x) => 1 | (set-value! x 33) => undefined | (invert! x) => undefined | (value x) => 1/33 | | (unmake-method! x invert!) => undefined | | (invert! x) error--> ERROR: Method not supported: x | | File: slib.info, Node: Priority Queues, Next: Queues, Prev: Object, Up: Data Structures | Priority Queues --------------- `(require 'priority-queue)' - Function: make-heap PRED<? Returns a binary heap suitable which can be used for priority queue operations. - Function: heap-length HEAP Returns the number of elements in HEAP. - Procedure: heap-insert! HEAP ITEM Inserts ITEM into HEAP. ITEM can be inserted multiple times. The value returned is unspecified. - Function: heap-extract-max! HEAP Returns the item which is larger than all others according to the PRED<? argument to `make-heap'. If there are no items in HEAP, an error is signaled. The algorithm for priority queues was taken from `Introduction to Algorithms' by T. Cormen, C. Leiserson, R. Rivest. 1989 MIT Press. File: slib.info, Node: Queues, Next: Records, Prev: Priority Queues, Up: Data Structures Queues ------ `(require 'queue)' A "queue" is a list where elements can be added to both the front and rear, and removed from the front (i.e., they are what are often called "dequeues"). A queue may also be used like a stack. - Function: make-queue Returns a new, empty queue. - Function: queue? OBJ Returns `#t' if OBJ is a queue. - Function: queue-empty? Q Returns `#t' if the queue Q is empty. - Procedure: queue-push! Q DATUM Adds DATUM to the front of queue Q. - Procedure: enquque! Q DATUM Adds DATUM to the rear of queue Q. All of the following functions raise an error if the queue Q is empty. - Function: queue-front Q Returns the datum at the front of the queue Q. - Function: queue-rear Q Returns the datum at the rear of the queue Q. - Prcoedure: queue-pop! Q - Procedure: dequeue! Q Both of these procedures remove and return the datum at the front of the queue. `queue-pop!' is used to suggest that the queue is being used like a stack. File: slib.info, Node: Records, Next: Structures, Prev: Queues, Up: Data Structures Records ------- `(require 'record)' The Record package provides a facility for user to define their own record data types. - Function: make-record-type TYPE-NAME FIELD-NAMES Returns a "record-type descriptor", a value representing a new data type disjoint from all others. The TYPE-NAME argument must be a string, but is only used for debugging purposes (such as the printed representation of a record of the new type). The FIELD-NAMES argument is a list of symbols naming the "fields" of a record of the new type. It is an error if the list contains any duplicates. It is unspecified how record-type descriptors are represented. - Function: record-constructor RTD [FIELD-NAMES] Returns a procedure for constructing new members of the type represented by RTD. The returned procedure accepts exactly as many arguments as there are symbols in the given list, FIELD-NAMES; these are used, in order, as the initial values of those fields in a new record, which is returned by the constructor procedure. The values of any fields not named in that list are unspecified. The FIELD-NAMES argument defaults to the list of field names in the call to `make-record-type' that created the type represented by RTD; if the FIELD-NAMES argument is provided, it is an error if it contains any duplicates or any symbols not in the default list. - Function: record-predicate RTD Returns a procedure for testing membership in the type represented by RTD. The returned procedure accepts exactly one argument and returns a true value if the argument is a member of the indicated record type; it returns a false value otherwise. - Function: record-accessor RTD FIELD-NAME Returns a procedure for reading the value of a particular field of a member of the type represented by RTD. The returned procedure accepts exactly one argument which must be a record of the appropriate type; it returns the current value of the field named by the symbol FIELD-NAME in that record. The symbol FIELD-NAME must be a member of the list of field-names in the call to `make-record-type' that created the type represented by RTD. - Function: record-modifier RTD FIELD-NAME Returns a procedure for writing the value of a particular field of a member of the type represented by RTD. The returned procedure accepts exactly two arguments: first, a record of the appropriate type, and second, an arbitrary Scheme value; it modifies the field named by the symbol FIELD-NAME in that record to contain the given value. The returned value of the modifier procedure is unspecified. The symbol FIELD-NAME must be a member of the list of field-names in the call to `make-record-type' that created the type represented by RTD. In May of 1996, as a product of discussion on the `rrrs-authors' mailing list, I rewrote `record.scm' to portably implement type disjointness for record data types. As long as an implementation's procedures are opaque and the `record' code is loaded before other programs, this will give disjoint record types which are unforgeable and incorruptible by R4RS procedures. As a consequence, the procedures `record?', `record-type-descriptor', `record-type-name'.and `record-type-field-names' are no longer supported. File: slib.info, Node: Structures, Prev: Records, Up: Data Structures Structures ---------- `(require 'struct)' (uses defmacros) `defmacro's which implement "records" from the book `Essentials of Programming Languages' by Daniel P. Friedman, M. Wand and C.T. Haynes. Copyright 1992 Jeff Alexander, Shinnder Lee, and Lewis Patterson Matthew McDonald <mafm@cs.uwa.edu.au> added field setters. - Macro: define-record TAG (VAR1 VAR2 ...) Defines several functions pertaining to record-name TAG: - Function: make-TAG VAR1 VAR2 ... - Function: TAG? OBJ - Function: TAG->VAR1 OBJ - Function: TAG->VAR2 OBJ ... - Function: set-TAG-VAR1! OBJ VAL - Function: set-TAG-VAR2! OBJ VAL ... Here is an example of its use. (define-record term (operator left right)) => #<unspecified> (define foo (make-term 'plus 1 2)) => foo (term->left foo) => 1 (set-term-left! foo 2345) => #<unspecified> (term->left foo) => 2345 - Macro: variant-case EXP (TAG (VAR1 VAR2 ...) BODY) ... executes the following for the matching clause: ((lambda (VAR1 VAR ...) BODY) (TAG->VAR1 EXP) (TAG->VAR2 EXP) ...) File: slib.info, Node: Procedures, Next: Standards Support, Prev: Data Structures, Up: Other Packages Procedures ========== Anything that doesn't fall neatly into any of the other categories winds up here. * Menu: * Common List Functions:: 'common-list-functions * Tree Operations:: 'tree * Chapter Ordering:: 'chapter-order * Sorting:: 'sort * Topological Sort:: Keep your socks on. * String-Case:: 'string-case * String Ports:: 'string-port * String Search:: Also Search from a Port. * Line I/O:: 'line-i/o * Multi-Processing:: 'process File: slib.info, Node: Common List Functions, Next: Tree Operations, Prev: Procedures, Up: Procedures Common List Functions --------------------- `(require 'common-list-functions)' The procedures below follow the Common LISP equivalents apart from optional arguments in some cases. * Menu: * List construction:: * Lists as sets:: * Lists as sequences:: * Destructive list operations:: * Non-List functions:: File: slib.info, Node: List construction, Next: Lists as sets, Prev: Common List Functions, Up: Common List Functions List construction ................. - Function: make-list K . INIT `make-list' creates and returns a list of K elements. If INIT is included, all elements in the list are initialized to INIT. Example: (make-list 3) => (#<unspecified> #<unspecified> #<unspecified>) (make-list 5 'foo) => (foo foo foo foo foo) - Function: list* X . Y Works like `list' except that the cdr of the last pair is the last argument unless there is only one argument, when the result is just that argument. Sometimes called `cons*'. E.g.: (list* 1) => 1 (list* 1 2 3) => (1 2 . 3) (list* 1 2 '(3 4)) => (1 2 3 4) (list* ARGS '()) == (list ARGS) - Function: copy-list LST `copy-list' makes a copy of LST using new pairs and returns it. Only the top level of the list is copied, i.e., pairs forming elements of the copied list remain `eq?' to the corresponding elements of the original; the copy is, however, not `eq?' to the original, but is `equal?' to it. Example: (copy-list '(foo foo foo)) => (foo foo foo) (define q '(foo bar baz bang)) (define p q) (eq? p q) => #t (define r (copy-list q)) (eq? q r) => #f (equal? q r) => #t (define bar '(bar)) (eq? bar (car (copy-list (list bar 'foo)))) => #t File: slib.info, Node: Lists as sets, Next: Lists as sequences, Prev: List construction, Up: Common List Functions Lists as sets ............. `eqv?' is used to test for membership by procedures which treat lists as sets. - Function: adjoin E L `adjoin' returns the adjoint of the element E and the list L. That is, if E is in L, `adjoin' returns L, otherwise, it returns `(cons E L)'. Example: (adjoin 'baz '(bar baz bang)) => (bar baz bang) (adjoin 'foo '(bar baz bang)) => (foo bar baz bang) - Function: union L1 L2 `union' returns the combination of L1 and L2. Duplicates between L1 and L2 are culled. Duplicates within L1 or within L2 may or may not be removed. Example: (union '(1 2 3 4) '(5 6 7 8)) => (4 3 2 1 5 6 7 8) (union '(1 2 3 4) '(3 4 5 6)) => (2 1 3 4 5 6) - Function: intersection L1 L2 `intersection' returns all elements that are in both L1 and L2. Example: (intersection '(1 2 3 4) '(3 4 5 6)) => (3 4) (intersection '(1 2 3 4) '(5 6 7 8)) => () - Function: set-difference L1 L2 `set-difference' returns the union of all elements that are in L1 but not in L2. Example: (set-difference '(1 2 3 4) '(3 4 5 6)) => (1 2) (set-difference '(1 2 3 4) '(1 2 3 4 5 6)) => () - Function: member-if PRED LST `member-if' returns LST if `(PRED ELEMENT)' is `#t' for any ELEMENT in LST. Returns `#f' if PRED does not apply to any ELEMENT in LST. Example: (member-if vector? '(1 2 3 4)) => #f (member-if number? '(1 2 3 4)) => (1 2 3 4) - Function: some PRED LST . MORE-LSTS PRED is a boolean function of as many arguments as there are list arguments to `some' i.e., LST plus any optional arguments. PRED is applied to successive elements of the list arguments in order. `some' returns `#t' as soon as one of these applications returns `#t', and is `#f' if none returns `#t'. All the lists should have the same length. Example: (some odd? '(1 2 3 4)) => #t (some odd? '(2 4 6 8)) => #f (some > '(2 3) '(1 4)) => #f - Function: every PRED LST . MORE-LSTS `every' is analogous to `some' except it returns `#t' if every application of PRED is `#t' and `#f' otherwise. Example: (every even? '(1 2 3 4)) => #f (every even? '(2 4 6 8)) => #t (every > '(2 3) '(1 4)) => #f - Function: notany PRED . LST `notany' is analogous to `some' but returns `#t' if no application of PRED returns `#t' or `#f' as soon as any one does. - Function: notevery PRED . LST `notevery' is analogous to `some' but returns `#t' as soon as an application of PRED returns `#f', and `#f' otherwise. Example: (notevery even? '(1 2 3 4)) => #t (notevery even? '(2 4 6 8)) => #f - Function: find-if PRED LST `find-if' searches for the first ELEMENT in LST such that `(PRED ELEMENT)' returns `#t'. If it finds any such ELEMENT in LST, ELEMENT is returned. Otherwise, `#f' is returned. Example: (find-if number? '(foo 1 bar 2)) => 1 (find-if number? '(foo bar baz bang)) => #f (find-if symbol? '(1 2 foo bar)) => foo - Function: remove ELT LST `remove' removes all occurrences of ELT from LST using `eqv?' to test for equality and returns everything that's left. N.B.: other implementations (Chez, Scheme->C and T, at least) use `equal?' as the equality test. Example: (remove 1 '(1 2 1 3 1 4 1 5)) => (2 3 4 5) (remove 'foo '(bar baz bang)) => (bar baz bang) - Function: remove-if PRED LST `remove-if' removes all ELEMENTs from LST where `(PRED ELEMENT)' is `#t' and returns everything that's left. Example: (remove-if number? '(1 2 3 4)) => () (remove-if even? '(1 2 3 4 5 6 7 8)) => (1 3 5 7) - Function: remove-if-not PRED LST `remove-if-not' removes all ELEMENTs from LST for which `(PRED ELEMENT)' is `#f' and returns everything that's left. Example: (remove-if-not number? '(foo bar baz)) => () (remove-if-not odd? '(1 2 3 4 5 6 7 8)) => (1 3 5 7) - Function: has-duplicates? LST returns `#t' if 2 members of LST are `equal?', `#f' otherwise. Example: (has-duplicates? '(1 2 3 4)) => #f (has-duplicates? '(2 4 3 4)) => #t The procedure `remove-duplicates' uses `member' (rather than `memv'). - Function: remove-duplicates LST returns a copy of LST with its duplicate members removed. Elements are considered duplicate if they are `equal?'. Example: (remove-duplicates '(1 2 3 4)) => (4 3 2 1) (remove-duplicates '(2 4 3 4)) => (3 4 2) File: slib.info, Node: Lists as sequences, Next: Destructive list operations, Prev: Lists as sets, Up: Common List Functions Lists as sequences .................. - Function: position OBJ LST `position' returns the 0-based position of OBJ in LST, or `#f' if OBJ does not occur in LST. Example: (position 'foo '(foo bar baz bang)) => 0 (position 'baz '(foo bar baz bang)) => 2 (position 'oops '(foo bar baz bang)) => #f - Function: reduce P LST `reduce' combines all the elements of a sequence using a binary operation (the combination is left-associative). For example, using `+', one can add up all the elements. `reduce' allows you to apply a function which accepts only two arguments to more than 2 objects. Functional programmers usually refer to this as "foldl". `collect:reduce' (*Note Collections::) provides a version of `collect' generalized to collections. Example: (reduce + '(1 2 3 4)) => 10 (define (bad-sum . l) (reduce + l)) (bad-sum 1 2 3 4) == (reduce + (1 2 3 4)) == (+ (+ (+ 1 2) 3) 4) => 10 (bad-sum) == (reduce + ()) => () (reduce string-append '("hello" "cruel" "world")) == (string-append (string-append "hello" "cruel") "world") => "hellocruelworld" (reduce anything '()) => () (reduce anything '(x)) => x What follows is a rather non-standard implementation of `reverse' in terms of `reduce' and a combinator elsewhere called "C". ;;; Contributed by Jussi Piitulainen (jpiitula@ling.helsinki.fi) (define commute (lambda (f) (lambda (x y) (f y x)))) (define reverse (lambda (args) (reduce-init (commute cons) '() args))) - Function: reduce-init P INIT LST `reduce-init' is the same as reduce, except that it implicitly inserts INIT at the start of the list. `reduce-init' is preferred if you want to handle the null list, the one-element, and lists with two or more elements consistently. It is common to use the operator's idempotent as the initializer. Functional programmers usually call this "foldl". Example: (define (sum . l) (reduce-init + 0 l)) (sum 1 2 3 4) == (reduce-init + 0 (1 2 3 4)) == (+ (+ (+ (+ 0 1) 2) 3) 4) => 10 (sum) == (reduce-init + 0 '()) => 0 (reduce-init string-append "@" '("hello" "cruel" "world")) == (string-append (string-append (string-append "@" "hello") "cruel") "world") => "@hellocruelworld" Given a differentiation of 2 arguments, `diff', the following will differentiate by any number of variables. (define (diff* exp . vars) (reduce-init diff exp vars)) Example: ;;; Real-world example: Insertion sort using reduce-init. (define (insert l item) (if (null? l) (list item) (if (< (car l) item) (cons (car l) (insert (cdr l) item)) (cons item l)))) (define (insertion-sort l) (reduce-init insert '() l)) (insertion-sort '(3 1 4 1 5) == (reduce-init insert () (3 1 4 1 5)) == (insert (insert (insert (insert (insert () 3) 1) 4) 1) 5) == (insert (insert (insert (insert (3)) 1) 4) 1) 5) == (insert (insert (insert (1 3) 4) 1) 5) == (insert (insert (1 3 4) 1) 5) == (insert (1 1 3 4) 5) => (1 1 3 4 5) - Function: last LST N `last' returns the last N elements of LST. N must be a non-negative integer. Example: (last '(foo bar baz bang) 2) => (baz bang) (last '(1 2 3) 0) => 0 - Function: butlast LST N `butlast' returns all but the last N elements of LST. Example: (butlast '(a b c d) 3) => (a) (butlast '(a b c d) 4) => () `last' and `butlast' split a list into two parts when given identical arugments. (last '(a b c d e) 2) => (d e) (butlast '(a b c d e) 2) => (a b c) - Function: nthcdr N LST `nthcdr' takes N `cdr's of LST and returns the result. Thus `(nthcdr 3 LST)' == `(cdddr LST)' Example: (nthcdr 2 '(a b c d)) => (c d) (nthcdr 0 '(a b c d)) => (a b c d) - Function: butnthcdr N LST `butnthcdr' returns all but the nthcdr N elements of LST. Example: (butnthcdr 3 '(a b c d)) => (a b c) (butnthcdr 4 '(a b c d)) => () `nthcdr' and `butnthcdr' split a list into two parts when given identical arugments. (nthcdr 2 '(a b c d e)) => (c d e) (butnthcdr 2 '(a b c d e)) => (a b) File: slib.info, Node: Destructive list operations, Next: Non-List functions, Prev: Lists as sequences, Up: Common List Functions Destructive list operations ........................... These procedures may mutate the list they operate on, but any such mutation is undefined. - Procedure: nconc ARGS `nconc' destructively concatenates its arguments. (Compare this with `append', which copies arguments rather than destroying them.) Sometimes called `append!' (*Note Rev2 Procedures::). Example: You want to find the subsets of a set. Here's the obvious way: (define (subsets set) (if (null? set) '(()) (append (mapcar (lambda (sub) (cons (car set) sub)) (subsets (cdr set))) (subsets (cdr set))))) But that does way more consing than you need. Instead, you could replace the `append' with `nconc', since you don't have any need for all the intermediate results. Example: (define x '(a b c)) (define y '(d e f)) (nconc x y) => (a b c d e f) x => (a b c d e f) `nconc' is the same as `append!' in `sc2.scm'. - Procedure: nreverse LST `nreverse' reverses the order of elements in LST by mutating `cdr's of the list. Sometimes called `reverse!'. Example: (define foo '(a b c)) (nreverse foo) => (c b a) foo => (a) Some people have been confused about how to use `nreverse', thinking that it doesn't return a value. It needs to be pointed out that (set! lst (nreverse lst)) is the proper usage, not (nreverse lst) The example should suffice to show why this is the case. - Procedure: delete ELT LST - Procedure: delete-if PRED LST - Procedure: delete-if-not PRED LST Destructive versions of `remove' `remove-if', and `remove-if-not'. Example: (define lst '(foo bar baz bang)) (delete 'foo lst) => (bar baz bang) lst => (foo bar baz bang) (define lst '(1 2 3 4 5 6 7 8 9)) (delete-if odd? lst) => (2 4 6 8) lst => (1 2 4 6 8) Some people have been confused about how to use `delete', `delete-if', and `delete-if', thinking that they dont' return a value. It needs to be pointed out that (set! lst (delete el lst)) is the proper usage, not (delete el lst) The examples should suffice to show why this is the case. File: slib.info, Node: Non-List functions, Prev: Destructive list operations, Up: Common List Functions Non-List functions .................. - Function: and? . ARGS `and?' checks to see if all its arguments are true. If they are, `and?' returns `#t', otherwise, `#f'. (In contrast to `and', this is a function, so all arguments are always evaluated and in an unspecified order.) Example: (and? 1 2 3) => #t (and #f 1 2) => #f - Function: or? . ARGS `or?' checks to see if any of its arguments are true. If any is true, `or?' returns `#t', and `#f' otherwise. (To `or' as `and?' is to `and'.) Example: (or? 1 2 #f) => #t (or? #f #f #f) => #f - Function: atom? OBJECT Returns `#t' if OBJECT is not a pair and `#f' if it is pair. (Called `atom' in Common LISP.) (atom? 1) => #t (atom? '(1 2)) => #f (atom? #(1 2)) ; dubious! => #t - Function: type-of OBJECT Returns a symbol name for the type of OBJECT. - Function: coerce OBJECT RESULT-TYPE Converts and returns OBJECT of type `char', `number', `string', `symbol', `list', or `vector' to RESULT-TYPE (which must be one of these symbols). File: slib.info, Node: Tree Operations, Next: Chapter Ordering, Prev: Common List Functions, Up: Procedures Tree operations --------------- `(require 'tree)' These are operations that treat lists a representations of trees. - Function: subst NEW OLD TREE - Function: substq NEW OLD TREE - Function: substv NEW OLD TREE `subst' makes a copy of TREE, substituting NEW for every subtree or leaf of TREE which is `equal?' to OLD and returns a modified tree. The original TREE is unchanged, but may share parts with the result. `substq' and `substv' are similar, but test against OLD using `eq?' and `eqv?' respectively. Examples: (substq 'tempest 'hurricane '(shakespeare wrote (the hurricane))) => (shakespeare wrote (the tempest)) (substq 'foo '() '(shakespeare wrote (twelfth night))) => (shakespeare wrote (twelfth night . foo) . foo) (subst '(a . cons) '(old . pair) '((old . spice) ((old . shoes) old . pair) (old . pair))) => ((old . spice) ((old . shoes) a . cons) (a . cons)) - Function: copy-tree TREE Makes a copy of the nested list structure TREE using new pairs and returns it. All levels are copied, so that none of the pairs in the tree are `eq?' to the original ones - only the leaves are. Example: (define bar '(bar)) (copy-tree (list bar 'foo)) => ((bar) foo) (eq? bar (car (copy-tree (list bar 'foo)))) => #f File: slib.info, Node: Chapter Ordering, Next: Sorting, Prev: Tree Operations, Up: Procedures Chapter Ordering ---------------- `(require 'chapter-order)' The `chap:' functions deal with strings which are ordered like chapter numbers (or letters) in a book. Each section of the string consists of consecutive numeric or consecutive aphabetic characters of like case. - Function: chap:string<? STRING1 STRING2 Returns #t if the first non-matching run of alphabetic upper-case or the first non-matching run of alphabetic lower-case or the first non-matching run of numeric characters of STRING1 is `string<?' than the corresponding non-matching run of characters of STRING2. (chap:string<? "a.9" "a.10") => #t (chap:string<? "4c" "4aa") => #t (chap:string<? "Revised^{3.99}" "Revised^{4}") => #t - Function: chap:string>? STRING1 STRING2 - Function: chap:string<=? STRING1 STRING2 - Function: chap:string>=? STRING1 STRING2 Implement the corresponding chapter-order predicates. - Function: chap:next-string STRING Returns the next string in the *chapter order*. If STRING has no alphabetic or numeric characters, `(string-append STRING "0")' is returnd. The argument to chap:next-string will always be `chap:string<?' than the result. (chap:next-string "a.9") => "a.10" (chap:next-string "4c") => "4d" (chap:next-string "4z") => "4aa" (chap:next-string "Revised^{4}") => "Revised^{5}" File: slib.info, Node: Sorting, Next: Topological Sort, Prev: Chapter Ordering, Up: Procedures Sorting ------- `(require 'sort)' Many Scheme systems provide some kind of sorting functions. They do not, however, always provide the *same* sorting functions, and those that I have had the opportunity to test provided inefficient ones (a common blunder is to use quicksort which does not perform well). Because `sort' and `sort!' are not in the standard, there is very little agreement about what these functions look like. For example, Dybvig says that Chez Scheme provides (merge predicate list1 list2) (merge! predicate list1 list2) (sort predicate list) (sort! predicate list) while MIT Scheme 7.1, following Common LISP, offers unstable (sort list predicate) TI PC Scheme offers (sort! list/vector predicate?) and Elk offers (sort list/vector predicate?) (sort! list/vector predicate?) Here is a comprehensive catalogue of the variations I have found. 1. Both `sort' and `sort!' may be provided. 2. `sort' may be provided without `sort!'. 3. `sort!' may be provided without `sort'. 4. Neither may be provided. 5. The sequence argument may be either a list or a vector. 6. The sequence argument may only be a list. 7. The sequence argument may only be a vector. 8. The comparison function may be expected to behave like `<'. 9. The comparison function may be expected to behave like `<='. 10. The interface may be `(sort predicate? sequence)'. 11. The interface may be `(sort sequence predicate?)'. 12. The interface may be `(sort sequence &optional (predicate? <))'. 13. The sort may be stable. 14. The sort may be unstable. All of this variation really does not help anybody. A nice simple merge sort is both stable and fast (quite a lot faster than *quick* sort). I am providing this source code with no restrictions at all on its use (but please retain D.H.D.Warren's credit for the original idea). You may have to rename some of these functions in order to use them in a system which already provides incompatible or inferior sorts. For each of the functions, only the top-level define needs to be edited to do that. I could have given these functions names which would not clash with any Scheme that I know of, but I would like to encourage implementors to converge on a single interface, and this may serve as a hint. The argument order for all functions has been chosen to be as close to Common LISP as made sense, in order to avoid NIH-itis. Each of the five functions has a required *last* parameter which is a comparison function. A comparison function `f' is a function of 2 arguments which acts like `<'. For example, (not (f x x)) (and (f x y) (f y z)) == (f x z) The standard functions `<', `>', `char<?', `char>?', `char-ci<?', `char-ci>?', `string<?', `string>?', `string-ci<?', and `string-ci>?' are suitable for use as comparison functions. Think of `(less? x y)' as saying when `x' must *not* precede `y'. - Function: sorted? SEQUENCE LESS? Returns `#t' when the sequence argument is in non-decreasing order according to LESS? (that is, there is no adjacent pair `... x y ...' for which `(less? y x)'). Returns `#f' when the sequence contains at least one out-of-order pair. It is an error if the sequence is neither a list nor a vector. - Function: merge LIST1 LIST2 LESS? This merges two lists, producing a completely new list as result. I gave serious consideration to producing a Common-LISP-compatible version. However, Common LISP's `sort' is our `sort!' (well, in fact Common LISP's `stable-sort' is our `sort!', merge sort is *fast* as well as stable!) so adapting CL code to Scheme takes a bit of work anyway. I did, however, appeal to CL to determine the *order* of the arguments. - Procedure: merge! LIST1 LIST2 LESS? Merges two lists, re-using the pairs of LIST1 and LIST2 to build the result. If the code is compiled, and LESS? constructs no new pairs, no pairs at all will be allocated. The first pair of the result will be either the first pair of LIST1 or the first pair of LIST2, but you can't predict which. The code of `merge' and `merge!' could have been quite a bit simpler, but they have been coded to reduce the amount of work done per iteration. (For example, we only have one `null?' test per iteration.) - Function: sort SEQUENCE LESS? Accepts either a list or a vector, and returns a new sequence which is sorted. The new sequence is the same type as the input. Always `(sorted? (sort sequence less?) less?)'. The original sequence is not altered in any way. The new sequence shares its *elements* with the old one; no elements are copied. - Procedure: sort! SEQUENCE LESS? Returns its sorted result in the original boxes. If the original sequence is a list, no new storage is allocated at all. If the original sequence is a vector, the sorted elements are put back in the same vector. Some people have been confused about how to use `sort!', thinking that it doesn't return a value. It needs to be pointed out that (set! slist (sort! slist <)) is the proper usage, not (sort! slist <) Note that these functions do *not* accept a CL-style `:key' argument. A simple device for obtaining the same expressiveness is to define (define (keyed less? key) (lambda (x y) (less? (key x) (key y)))) and then, when you would have written (sort a-sequence #'my-less :key #'my-key) in Common LISP, just write (sort! a-sequence (keyed my-less? my-key)) in Scheme. File: slib.info, Node: Topological Sort, Next: String-Case, Prev: Sorting, Up: Procedures Topological Sort ---------------- `(require 'topological-sort)' or `(require 'tsort)' The algorithm is inspired by Cormen, Leiserson and Rivest (1990) `Introduction to Algorithms', chapter 23. - Function: tsort DAG PRED - Function: topological-sort DAG PRED where DAG is a list of sublists. The car of each sublist is a vertex. The cdr is the adjacency list of that vertex, i.e. a list of all vertices to which there exists an edge from the car vertex. PRED is one of `eq?', `eqv?', `equal?', `=', `char=?', `char-ci=?', `string=?', or `string-ci=?'. Sort the directed acyclic graph DAG so that for every edge from vertex U to V, U will come before V in the resulting list of vertices. Time complexity: O (|V| + |E|) Example (from Cormen): Prof. Bumstead topologically sorts his clothing when getting dressed. The first argument to `tsort' describes which garments he needs to put on before others. (For example, Prof Bumstead needs to put on his shirt before he puts on his tie or his belt.) `tsort' gives the correct order of dressing: (require 'tsort) (tsort '((shirt tie belt) (tie jacket) (belt jacket) (watch) (pants shoes belt) (undershorts pants shoes) (socks shoes)) eq?) => (socks undershorts pants shoes watch shirt belt tie jacket) File: slib.info, Node: String-Case, Next: String Ports, Prev: Topological Sort, Up: Procedures String-Case ----------- `(require 'string-case)' - Procedure: string-upcase STR - Procedure: string-downcase STR - Procedure: string-capitalize STR The obvious string conversion routines. These are non-destructive. - Function: string-upcase! STR - Function: string-downcase! STR - Function: string-captialize! STR The destructive versions of the functions above. - Function: string-ci->symbol STR Converts string STR to a symbol having the same case as if the symbol had been `read'. File: slib.info, Node: String Ports, Next: String Search, Prev: String-Case, Up: Procedures String Ports ------------ `(require 'string-port)' - Procedure: call-with-output-string PROC PROC must be a procedure of one argument. This procedure calls PROC with one argument: a (newly created) output port. When the function returns, the string composed of the characters written into the port is returned. - Procedure: call-with-input-string STRING PROC PROC must be a procedure of one argument. This procedure calls PROC with one argument: an (newly created) input port from which STRING's contents may be read. When PROC returns, the port is closed and the value yielded by the procedure PROC is returned. File: slib.info, Node: String Search, Next: Line I/O, Prev: String Ports, Up: Procedures String Search ------------- `(require 'string-search)' - Procedure: string-index STRING CHAR - Procedure: string-index-ci STRING CHAR Returns the index of the first occurence of CHAR within STRING, or `#f' if the STRING does not contain a character CHAR. - Procedure: string-reverse-index STRING CHAR - Procedure: string-reverse-index-ci STRING CHAR Returns the index of the last occurence of CHAR within STRING, or `#f' if the STRING does not contain a character CHAR. - procedure: substring? PATTERN STRING - procedure: substring-ci? PATTERN STRING Searches STRING to see if some substring of STRING is equal to PATTERN. `substring?' returns the index of the first character of the first substring of STRING that is equal to PATTERN; or `#f' if STRING does not contain PATTERN. (substring? "rat" "pirate") => 2 (substring? "rat" "outrage") => #f (substring? "" any-string) => 0 - Procedure: find-string-from-port? STR IN-PORT MAX-NO-CHARS Looks for a string STR within the first MAX-NO-CHARS chars of the input port IN-PORT. - Procedure: find-string-from-port? STR IN-PORT When called with two arguments, the search span is limited by the end of the input stream. - Procedure: find-string-from-port? STR IN-PORT CHAR Searches up to the first occurrence of character CHAR in STR. - Procedure: find-string-from-port? STR IN-PORT PROC Searches up to the first occurrence of the procedure PROC returning non-false when called with a character (from IN-PORT) argument. When the STR is found, `find-string-from-port?' returns the number of characters it has read from the port, and the port is set to read the first char after that (that is, after the STR) The function returns `#f' when the STR isn't found. `find-string-from-port?' reads the port *strictly* sequentially, and does not perform any buffering. So `find-string-from-port?' can be used even if the IN-PORT is open to a pipe or other communication channel. - Function: string-subst TXT OLD1 NEW1 ... Returns a copy of string TXT with all occurrences of string OLD1 in TXT replaced with NEW1, OLD2 replaced with NEW2 .... File: slib.info, Node: Line I/O, Next: Multi-Processing, Prev: String Search, Up: Procedures Line I/O -------- `(require 'line-i/o)' - Function: read-line READ-LINE | - Function: read-line READ-LINE PORT | Returns a string of the characters up to, but not including a newline or end of file, updating PORT to point to the character following the newline. If no characters are available, an end of file object is returned. The PORT argument may be omitted, in | which case it defaults to the value returned by | `current-input-port'. | - Function: read-line! READ-LINE! STRING | - Function: read-line! READ-LINE! STRING PORT | Fills READ-LINE! with characters up to, but not including a | newline or end of file, updating the PORT to point to the last | character read or following the newline if it was read. If no | characters are available, an end of file object is returned. If a | newline or end of file was found, the number of characters read is | returned. Otherwise, `#f' is returned. The PORT argument may be | omitted, in which case it defaults to the value returned by | `current-input-port'. | | - Function: write-line WRITE-LINE STRING | - Function: write-line WRITE-LINE STRING PORT | Writes WRITE-LINE followed by a newline to the given PORT and | returns an unspecified value. The PORT argument may be omited, in | which case it defaults to the value returned by | `current-input-port'. | | - Function: display-file PATH | - Function: display-file PATH PORT | Displays the contents of the file named by PATH to PORT. The PORT | argument may be ommited, in which case it defaults to the value | returned by `current-output-port'. | File: slib.info, Node: Multi-Processing, Prev: Line I/O, Up: Procedures Multi-Processing ---------------- `(require 'process)' This module implements asynchronous (non-polled) time-sliced multi-processing in the SCM Scheme implementation using procedures `alarm' and `alarm-interrupt'. Until this is ported to another implementation, consider it an example of writing schedulers in Scheme. - Procedure: add-process! PROC Adds proc, which must be a procedure (or continuation) capable of accepting accepting one argument, to the `process:queue'. The value returned is unspecified. The argument to PROC should be ignored. If PROC returns, the process is killed. - Procedure: process:schedule! Saves the current process on `process:queue' and runs the next process from `process:queue'. The value returned is unspecified. - Procedure: kill-process! Kills the current process and runs the next process from `process:queue'. If there are no more processes on `process:queue', `(slib:exit)' is called (*Note System::). File: slib.info, Node: Standards Support, Next: Session Support, Prev: Procedures, Up: Other Packages Standards Support ================= * Menu: * With-File:: 'with-file * Transcripts:: 'transcript * Rev2 Procedures:: 'rev2-procedures * Rev4 Optional Procedures:: 'rev4-optional-procedures * Multi-argument / and -:: 'multiarg/and- * Multi-argument Apply:: 'multiarg-apply * Rationalize:: 'rationalize * Promises:: 'promise * Dynamic-Wind:: 'dynamic-wind * Eval:: 'eval * Values:: 'values File: slib.info, Node: With-File, Next: Transcripts, Prev: Standards Support, Up: Standards Support With-File --------- `(require 'with-file)' - Function: with-input-from-file FILE THUNK - Function: with-output-to-file FILE THUNK Description found in R4RS. File: slib.info, Node: Transcripts, Next: Rev2 Procedures, Prev: With-File, Up: Standards Support Transcripts ----------- `(require 'transcript)' - Function: transcript-on FILENAME - Function: transcript-off FILENAME Redefines `read-char', `read', `write-char', `write', `display', and `newline'. File: slib.info, Node: Rev2 Procedures, Next: Rev4 Optional Procedures, Prev: Transcripts, Up: Standards Support Rev2 Procedures --------------- `(require 'rev2-procedures)' The procedures below were specified in the `Revised^2 Report on Scheme'. *N.B.*: The symbols `1+' and `-1+' are not `R4RS' syntax. Scheme->C, for instance, barfs on this module. - Procedure: substring-move-left! STRING1 START1 END1 STRING2 START2 - Procedure: substring-move-right! STRING1 START1 END1 STRING2 START2 STRING1 and STRING2 must be a strings, and START1, START2 and END1 must be exact integers satisfying 0 <= START1 <= END1 <= (string-length STRING1) 0 <= START2 <= END1 - START1 + START2 <= (string-length STRING2) `substring-move-left!' and `substring-move-right!' store characters of STRING1 beginning with index START1 (inclusive) and ending with index END1 (exclusive) into STRING2 beginning with index START2 (inclusive). `substring-move-left!' stores characters in time order of increasing indices. `substring-move-right!' stores characters in time order of increasing indeces. - Procedure: substring-fill! STRING START END CHAR Fills the elements START-END of STRING with the character CHAR. - Function: string-null? STR == `(= 0 (string-length STR))' - Procedure: append! . PAIRS Destructively appends its arguments. Equivalent to `nconc'. - Function: 1+ N Adds 1 to N. - Function: -1+ N Subtracts 1 from N. - Function: <? - Function: <=? - Function: =? - Function: >? - Function: >=? These are equivalent to the procedures of the same name but without the trailing `?'. File: slib.info, Node: Rev4 Optional Procedures, Next: Multi-argument / and -, Prev: Rev2 Procedures, Up: Standards Support Rev4 Optional Procedures ------------------------ `(require 'rev4-optional-procedures)' For the specification of these optional procedures, *Note Standard procedures: (r4rs)Standard procedures. - Function: list-tail L P - Function: string->list S - Function: list->string L - Function: string-copy - Procedure: string-fill! S OBJ - Function: list->vector L - Function: vector->list S - Procedure: vector-fill! S OBJ File: slib.info, Node: Multi-argument / and -, Next: Multi-argument Apply, Prev: Rev4 Optional Procedures, Up: Standards Support Multi-argument / and - ---------------------- `(require 'mutliarg/and-)' For the specification of these optional forms, *Note Numerical operations: (r4rs)Numerical operations. The `two-arg:'* forms are only defined if the implementation does not support the many-argument forms. - Function: two-arg:/ N1 N2 The original two-argument version of `/'. - Function: / DIVIDENT . DIVISORS - Function: two-arg:- N1 N2 The original two-argument version of `-'. - Function: - MINUEND . SUBTRAHENDS File: slib.info, Node: Multi-argument Apply, Next: Rationalize, Prev: Multi-argument / and -, Up: Standards Support Multi-argument Apply -------------------- `(require 'multiarg-apply)' For the specification of this optional form, *Note Control features: (r4rs)Control features. - Function: two-arg:apply PROC L The implementation's native `apply'. Only defined for implementations which don't support the many-argument version. - Function: apply PROC . ARGS File: slib.info, Node: Rationalize, Next: Promises, Prev: Multi-argument Apply, Up: Standards Support Rationalize ----------- `(require 'rationalize)' The procedure rationalize is interesting because most programming languages do not provide anything analogous to it. For simplicity, we present an algorithm which computes the correct result for exact arguments (provided the implementation supports exact rational numbers of unlimited precision), and produces a reasonable answer for inexact arguments when inexact arithmetic is implemented using floating-point. We thank Alan Bawden for contributing this algorithm. - Function: rationalize X E File: slib.info, Node: Promises, Next: Dynamic-Wind, Prev: Rationalize, Up: Standards Support Promises -------- `(require 'promise)' - Function: make-promise PROC Change occurrences of `(delay EXPRESSION)' to `(make-promise (lambda () EXPRESSION))' and `(define force promise:force)' to implement promises if your implementation doesn't support them (*note Control features: (r4rs)Control features.). File: slib.info, Node: Dynamic-Wind, Next: Eval, Prev: Promises, Up: Standards Support Dynamic-Wind ------------ `(require 'dynamic-wind)' This facility is a generalization of Common LISP `unwind-protect', designed to take into account the fact that continuations produced by `call-with-current-continuation' may be reentered. - Procedure: dynamic-wind THUNK1 THUNK2 THUNK3 The arguments THUNK1, THUNK2, and THUNK3 must all be procedures of no arguments (thunks). `dynamic-wind' calls THUNK1, THUNK2, and then THUNK3. The value returned by THUNK2 is returned as the result of `dynamic-wind'. THUNK3 is also called just before control leaves the dynamic context of THUNK2 by calling a continuation created outside that context. Furthermore, THUNK1 is called before reentering the dynamic context of THUNK2 by calling a continuation created inside that context. (Control is inside the context of THUNK2 if THUNK2 is on the current return stack). *Warning:* There is no provision for dealing with errors or interrupts. If an error or interrupt occurs while using `dynamic-wind', the dynamic environment will be that in effect at the time of the error or interrupt. File: slib.info, Node: Eval, Next: Values, Prev: Dynamic-Wind, Up: Standards Support `(require 'eval)' - Function: eval EXPRESSION ENVIRONMENT-SPECIFIER Evaluates EXPRESSION in the specified environment and returns its value. EXPRESSION must be a valid Scheme expression represented as data, and ENVIRONMENT-SPECIFIER must be a value returned by one of the three procedures described below. Implementations may extend `eval' to allow non-expression programs (definitions) as the first argument and to allow other values as environments, with the restriction that `eval' is not allowed to create new bindings in the environments associated with `null-environment' or `scheme-report-environment'. (eval '(* 7 3) (scheme-report-environment 5)) => 21 (let ((f (eval '(lambda (f x) (f x x)) (null-environment)))) (f + 10)) => 20 - Function: scheme-report-environment VERSION - Function: null-environment VERSION - Function: null-environment VERSION must be an exact non-negative integer N corresponding to a version of one of the Revised^N Reports on Scheme. `Scheme-report-environment' returns a specifier for an environment that contains the set of bindings specified in the corresponding report that the implementation supports. `Null-environment' returns a specifier for an environment that contains only the (syntactic) bindings for all the syntactic keywords defined in the given version of the report. Not all versions may be available in all implementations at all times. However, an implementation that conforms to version N of the Revised^N Reports on Scheme must accept version N. An error is signalled if the specified version is not available. The effect of assigning (through the use of `eval') a variable bound in a `scheme-report-environment' (for example `car') is unspecified. Thus the environments specified by `scheme-report-environment' may be immutable. - Function: interaction-environment This optional procedure returns a specifier for the environment that contains implementation-defined bindings, typically a superset of those listed in the report. The intent is that this procedure will return the environment in which the implementation would evaluate expressions dynamically typed by the user. Here are some more `eval' examples: (require 'eval) => #<unspecified> (define car 'volvo) => #<unspecified> car => volvo (eval 'car (interaction-environment)) => volvo (eval 'car (scheme-report-environment 5)) => #<primitive-procedure car> (eval '(eval 'car (interaction-environment)) (scheme-report-environment 5)) => volvo (eval '(eval '(set! car 'buick) (interaction-environment)) (scheme-report-environment 5)) => #<unspecified> car => buick (eval 'car (scheme-report-environment 5)) => #<primitive-procedure car> (eval '(eval 'car (interaction-environment)) (scheme-report-environment 5)) => buick File: slib.info, Node: Values, Prev: Eval, Up: Standards Support Values ------ `(require 'values)' - Function: values OBJ ... `values' takes any number of arguments, and passes (returns) them to its continuation. - Function: call-with-values THUNK PROC THUNK must be a procedure of no arguments, and PROC must be a procedure. `call-with-values' calls THUNK with a continuation that, when passed some values, calls PROC with those values as arguments. Except for continuations created by the `call-with-values' procedure, all continuations take exactly one value, as now; the effect of passing no value or more than one value to continuations that were not created by the `call-with-values' procedure is unspecified. File: slib.info, Node: Session Support, Next: Extra-SLIB Packages, Prev: Standards Support, Up: Other Packages Session Support =============== * Menu: * Repl:: Macros at top-level * Quick Print:: Loop-safe Output * Debug:: To err is human ... * Breakpoints:: Pause execution * Trace:: 'trace * System Interface:: 'system, 'getenv, and 'net-clients | File: slib.info, Node: Repl, Next: Quick Print, Prev: Session Support, Up: Session Support `(require 'repl)' Here is a read-eval-print-loop which, given an eval, evaluates forms. - Procedure: repl:top-level REPL:EVAL `read's, `repl:eval's and `write's expressions from `(current-input-port)' to `(current-output-port)' until an end-of-file is encountered. `load', `slib:eval', `slib:error', and `repl:quit' dynamically bound during `repl:top-level'. - Procedure: repl:quit Exits from the invocation of `repl:top-level'. The `repl:' procedures establish, as much as is possible to do portably, a top level environment supporting macros. `repl:top-level' uses `dynamic-wind' to catch error conditions and interrupts. If your implementation supports this you are all set. Otherwise, if there is some way your implementation can catch error conditions and interrupts, then have them call `slib:error'. It will display its arguments and reenter `repl:top-level'. `slib:error' dynamically bound by `repl:top-level'. To have your top level loop always use macros, add any interrupt catching lines and the following lines to your Scheme init file: (require 'macro) (require 'repl) (repl:top-level macro:eval) File: slib.info, Node: Quick Print, Next: Debug, Prev: Repl, Up: Session Support Quick Print ----------- `(require 'qp)' When displaying error messages and warnings, it is paramount that the output generated for circular lists and large data structures be limited. This section supplies a procedure to do this. It could be much improved. Notice that the neccessity for truncating output eliminates Common-Lisp's *Note Format:: from consideration; even when variables `*print-level*' and `*print-level*' are set, huge strings and bit-vectors are *not* limited. - Procedure: qp ARG1 ... - Procedure: qpn ARG1 ... - Procedure: qpr ARG1 ... `qp' writes its arguments, separated by spaces, to `(current-output-port)'. `qp' compresses printing by substituting `...' for substructure it does not have sufficient room to print. `qpn' is like `qp' but outputs a newline before returning. `qpr' is like `qpn' except that it returns its last argument. - Variable: *qp-width* `*qp-width*' is the largest number of characters that `qp' should use. File: slib.info, Node: Debug, Next: Breakpoints, Prev: Quick Print, Up: Session Support Debug ----- `(require 'debug)' Requiring `debug' automatically requires `trace' and `break'. An application with its own datatypes may want to substitute its own printer for `qp'. This example shows how to do this: (define qpn (lambda args) ...) (provide 'qp) (require 'debug) - Procedure: trace-all FILE Traces (*note Trace::.) all procedures `define'd at top-level in file `file'. - Procedure: break-all FILE Breakpoints (*note Breakpoints::.) all procedures `define'd at top-level in file `file'. File: slib.info, Node: Breakpoints, Next: Trace, Prev: Debug, Up: Session Support Breakpoints ----------- `(require 'break)' - Function: init-debug If your Scheme implementation does not support `break' or `abort', a message will appear when you `(require 'break)' or `(require 'debug)' telling you to type `(init-debug)'. This is in order to establish a top-level continuation. Typing `(init-debug)' at top level sets up a continuation for `break'. - Function: breakpoint ARG1 ... Returns from the top level continuation and pushes the continuation from which it was called on a continuation stack. - Function: continue Pops the topmost continuation off of the continuation stack and returns an unspecified value to it. - Function: continue ARG1 ... Pops the topmost continuation off of the continuation stack and returns ARG1 ... to it. - Macro: break PROC1 ... Redefines the top-level named procedures given as arguments so that `breakpoint' is called before calling PROC1 .... - Macro: break With no arguments, makes sure that all the currently broken identifiers are broken (even if those identifiers have been redefined) and returns a list of the broken identifiers. - Macro: unbreak PROC1 ... Turns breakpoints off for its arguments. - Macro: unbreak With no arguments, unbreaks all currently broken identifiers and returns a list of these formerly broken identifiers. The following routines are the procedures which actually do the tracing when this module is supplied by SLIB, rather than natively. If defmacros are not natively supported by your implementation, these might be more convenient to use. - Function: breakf PROC - Function: breakf PROC NAME - Function: debug:breakf PROC - Function: debug:breakf PROC NAME To break, type (set! SYMBOL (breakf SYMBOL)) or (set! SYMBOL (breakf SYMBOL 'SYMBOL)) or (define SYMBOL (breakf FUNCTION)) or (define SYMBOL (breakf FUNCTION 'SYMBOL)) - Function: unbreakf PROC - Function: debug:unbreakf PROC To unbreak, type (set! SYMBOL (unbreakf SYMBOL)) File: slib.info, Node: Trace, Next: System Interface, Prev: Breakpoints, Up: Session Support Tracing ------- `(require 'trace)' - Macro: trace PROC1 ... Traces the top-level named procedures given as arguments. - Macro: trace With no arguments, makes sure that all the currently traced identifiers are traced (even if those identifiers have been redefined) and returns a list of the traced identifiers. - Macro: untrace PROC1 ... Turns tracing off for its arguments. - Macro: untrace With no arguments, untraces all currently traced identifiers and returns a list of these formerly traced identifiers. The following routines are the procedures which actually do the tracing when this module is supplied by SLIB, rather than natively. If defmacros are not natively supported by your implementation, these might be more convenient to use. - Function: tracef PROC - Function: tracef PROC NAME - Function: debug:tracef PROC - Function: debug:tracef PROC NAME To trace, type (set! SYMBOL (tracef SYMBOL)) or (set! SYMBOL (tracef SYMBOL 'SYMBOL)) or (define SYMBOL (tracef FUNCTION)) or (define SYMBOL (tracef FUNCTION 'SYMBOL)) - Function: untracef PROC - Function: debug:untracef PROC To untrace, type (set! SYMBOL (untracef SYMBOL)) File: slib.info, Node: System Interface, Prev: Trace, Up: Session Support | System Interface ---------------- If `(provided? 'getenv)': - Function: getenv NAME Looks up NAME, a string, in the program environment. If NAME is found a string of its value is returned. Otherwise, `#f' is returned. If `(provided? 'system)': - Function: system COMMAND-STRING Executes the COMMAND-STRING on the computer and returns the integer status code. If `system' is provided by the Scheme implementation, the "net-clients" | package provides interfaces to common network client programs like FTP, | mail, and Netscape. | | `(require 'net-clients)' | | - Function: call-with-tmpnam PROC | - Function: call-with-tmpnam PROC K | Calls PROC with K arguments, strings returned by successive calls | to `tmpnam'. If PROC returns, then any files named by the | arguments to PROC are deleted automatically and the value(s) | yielded by the PROC is(are) returned. K may be ommited, in which | case it defaults to `1'. | | - Function: user-email-address | `user-email-address' returns a string of the form | `username@hostname'. If this e-mail address cannot be obtained, | #f is returned. | | - Function: current-directory | `current-directory' returns a string containing the absolute file | name representing the current working directory. If this string | cannot be obtained, #f is returned. | | If `current-directory' cannot be supported by the platform, the | value of `current-directory' is #f. | | - Function: make-directory NAME | Creates a sub-directory NAME of the current-directory. If | successful, `make-directory' returns #t; otherwise #f. | | - Function: null-directory? FILE-NAME | Returns #t if changing directory to FILE-NAME makes the current | working directory the same as it is before changing directory; | otherwise returns #f. | | - Function: absolute-path? FILE-NAME | Returns #t if FILE-NAME is a fully specified pathname (does not | depend on the current working directory); otherwise returns #f. | | - Function: glob-pattern? STR | Returns #t if the string STR contains characters used for | specifying glob patterns, namely `*', `?', or `['. | | - Function: parse-ftp-address URL | Returns a list of the decoded FTP URL; or #f if indecipherable. | FTP "Uniform Resource Locator", "ange-ftp", and "getit" formats | are handled. The returned list has four elements which are | strings or #f: | | 0. username | | 1. password | | 2. remote-site | | 3. remote-directory | | - Function: ftp-upload PATHS USER PASSWORD REMOTE-SITE REMOTE-DIR | PASSWORD must be a non-empty string or #f. PATHS must be a | non-empty list of pathnames or Glob patterns (*note Filenames::.) | matching files to transfer. | | `ftp-upload' puts the files specified by PATHS into the REMOTE-DIR | directory of FTP REMOTE-SITE using name USER with (optional) | PASSWORD. | | If PASSWORD is #f and USER is not `ftp' or `anonymous', then USER | is ignored; FTP takes the username and password from the `.netrc' | or equivalent file. | | - Function: path->url PATH | Returns a URL-string for PATH on the local host. | | - Function: browse-url-netscape URL | If a `netscape' browser is running, `browse-url-netscape' causes | the browser to display the page specified by string URL and | returns #t. | | If the browser is not running, `browse-url-netscape' runs | `netscape' with the argument URL. If the browser starts, | `browse-url-netscape' returns #t when the browser exits; otherwise | it returns #f. | File: slib.info, Node: Extra-SLIB Packages, Prev: Session Support, Up: Other Packages Extra-SLIB Packages =================== Several Scheme packages have been written using SLIB. There are several reasons why a package might not be included in the SLIB distribution: * Because it requires special hardware or software which is not universal. * Because it is large and of limited interest to most Scheme users. * Because it has copying terms different enough from the other SLIB packages that its inclusion would cause confusion. * Because it is an application program, rather than a library module. * Because I have been too busy to integrate it. Once an optional package is installed (and an entry added to `*catalog*', the `require' mechanism allows it to be called up and used as easily as any other SLIB package. Some optional packages (for which `*catalog*' already has entries) available from SLIB sites are: SLIB-PSD is a portable debugger for Scheme (requires emacs editor). swissnet.ai.mit.edu:pub/scm/slib-psd1-3.tar.gz ftp.gnu.org:pub/gnu/jacal/slib-psd1-3.tar.gz | ftp.maths.tcd.ie:pub/bosullvn/jacal/slib-psd1-3.tar.gz ftp.cs.indiana.edu:/pub/scheme-repository/utl/slib-psd1-3.tar.gz With PSD, you can run a Scheme program in an Emacs buffer, set breakpoints, single step evaluation and access and modify the program's variables. It works by instrumenting the original source code, so it should run with any R4RS compliant Scheme. It has been tested with SCM, Elk 1.5, and the sci interpreter in the Scheme->C system, but should work with other Schemes with a minimal amount of porting, if at all. Includes documentation and user's manual. Written by Pertti Kellom\"aki, pk@cs.tut.fi. The Lisp Pointers article describing PSD (Lisp Pointers VI(1):15-23, January-March 1993) is available as `http://www.cs.tut.fi/staff/pk/scheme/psd/article/article.html' SCHELOG is an embedding of Prolog in Scheme. `http://www.cs.rice.edu/CS/PLT/packages/schelog/' File: slib.info, Node: About SLIB, Next: Index, Prev: Other Packages, Up: Top About SLIB ********** * Menu: * Installation:: How to install SLIB on your system. * Porting:: SLIB to new platforms. * Coding Standards:: How to write modules for SLIB. * Copyrights:: Intellectual propery issues. More people than I can name have contributed to SLIB. Thanks to all of File: slib.info, Node: Installation, Next: Porting, Prev: About SLIB, Up: About SLIB Installation ============ Check the manifest in `README' to find a configuration file for your Scheme implementation. Initialization files for most IEEE P1178 compliant Scheme Implementations are included with this distribution. If the Scheme implementation supports `getenv', then the value of the shell environment variable SCHEME_LIBRARY_PATH will be used for `(library-vicinity)' if it is defined. Currently, Chez, Elk, MITScheme, scheme->c, VSCM, and SCM support `getenv'. Scheme48 supports `getenv' but does not use it for determining `library-vicinity'. (That is done from the Makefile.) You should check the definitions of `software-type', `scheme-implementation-version', `implementation-vicinity', and `library-vicinity' in the initialization file. There are comments in the file for how to configure it. Once this is done you can modify the startup file for your Scheme implementation to `load' this initialization file. SLIB is then installed. Multiple implementations of Scheme can all use the same SLIB directory. Simply configure each implementation's initialization file as outlined above. The SCM implementation does not require any initialization file as SLIB support is already built in to SCM. See the documentation with SCM for installation instructions. SLIB includes methods to create heap images for the VSCM and Scheme48 implementations. The instructions for creating a VSCM image are in comments in `vscm.init'. To make a Scheme48 image for an installation under `<prefix>', `cd' to the SLIB directory and type `make prefix=<prefix> slib48'. To install the image, type `make prefix=<prefix> install48'. This will also create a shell script with the name `slib48' which will invoke the saved image. File: slib.info, Node: Porting, Next: Coding Standards, Prev: Installation, Up: About SLIB Porting ======= If there is no initialization file for your Scheme implementation, you will have to create one. Your Scheme implementation must be largely compliant with `IEEE Std 1178-1990', `Revised^4 Report on the Algorithmic Language Scheme', or `Revised^5 Report on the Algorithmic Language Scheme' in order to support SLIB. (1) `Template.scm' is an example configuration file. The comments inside will direct you on how to customize it to reflect your system. Give your new initialization file the implementation's name with `.init' appended. For instance, if you were porting `foo-scheme' then the initialization file might be called `foo.init'. Your customized version should then be loaded as part of your scheme implementation's initialization. It will load `require.scm' from the library; this will allow the use of `provide', `provided?', and `require' along with the "vicinity" functions (these functions are documented in the section *Note Require::). The rest of the library will then be accessible in a system independent fashion. Please mail new working configuration files to `jaffer @ ai.mit.edu' | so that they can be included in the SLIB distribution. | ---------- Footnotes ---------- (1) If you are porting a `Revised^3 Report on the Algorithmic Language Scheme' implementation, then you will need to finish writing `sc4sc3.scm' and `load' it from your initialization file. File: slib.info, Node: Coding Standards, Next: Copyrights, Prev: Porting, Up: About SLIB Coding Standards ================ All library packages are written in IEEE P1178 Scheme and assume that a configuration file and `require.scm' package have already been loaded. Other versions of Scheme can be supported in library packages as well by using, for example, `(provided? 'rev3-report)' or `(require 'rev3-report)' (*Note Require::). The module name and `:' should prefix each symbol defined in the package. Definitions for external use should then be exported by having `(define foo module-name:foo)'. Code submitted for inclusion in SLIB should not duplicate routines already in SLIB files. Use `require' to force those library routines to be used by your package. Care should be taken that there are no circularities in the `require's and `load's between the library packages. Documentation should be provided in Emacs Texinfo format if possible, But documentation must be provided. Your package will be released sooner with SLIB if you send me a file which tests your code. Please run this test *before* you send me the code! Modifications ------------- Please document your changes. A line or two for `ChangeLog' is sufficient for simple fixes or extensions. Look at the format of `ChangeLog' to see what information is desired. Please send me `diff' files from the latest SLIB distribution (remember to send `diff's of `slib.texi' and `ChangeLog'). This makes for less email traffic and makes it easier for me to integrate when more than one person is changing a file (this happens a lot with `slib.texi' and `*.init' files). If someone else wrote a package you want to significantly modify, please try to contact the author, who may be working on a new version. This will insure against wasting effort on obsolete versions. Please *do not* reformat the source code with your favorite beautifier, make 10 fixes, and send me the resulting source code. I do not have the time to fish through 10000 diffs to find your 10 real fixes. File: slib.info, Node: Copyrights, Prev: Coding Standards, Up: About SLIB Copyrights ========== This section has instructions for SLIB authors regarding copyrights. Each package in SLIB must either be in the public domain, or come with a statement of terms permitting users to copy, redistribute and modify it. The comments at the beginning of `require.scm' and `macwork.scm' illustrate copyright and appropriate terms. If your code or changes amount to less than about 10 lines, you do not need to add your copyright or send a disclaimer. Putting code into the Public Domain ----------------------------------- In order to put code in the public domain you should sign a copyright disclaimer and send it to the SLIB maintainer. Contact jaffer @ | ai.mit.edu for the address to mail the disclaimer to. | I, NAME, hereby affirm that I have placed the software package NAME in the public domain. I affirm that I am the sole author and sole copyright holder for the software package, that I have the right to place this software package in the public domain, and that I will do nothing to undermine this status in the future. SIGNATURE AND DATE This wording assumes that you are the sole author. If you are not the sole author, the wording needs to be different. If you don't want to be bothered with sending a letter every time you release or modify a module, make your letter say that it also applies to your future revisions of that module. Make sure no employer has any claim to the copyright on the work you are submitting. If there is any doubt, create a copyright disclaimer and have your employer sign it. Mail the signed disclaimer to the SLIB maintainer. Contact jaffer @ ai.mit.edu for the address to mail the disclaimer to. An example disclaimer follows. Explicit copying terms ---------------------- If you submit more than about 10 lines of code which you are not placing into the Public Domain (by sending me a disclaimer) you need to: * Arrange that your name appears in a copyright line for the appropriate year. Multiple copyright lines are acceptable. * With your copyright line, specify any terms you require to be different from those already in the file. * Make sure no employer has any claim to the copyright on the work you are submitting. If there is any doubt, create a copyright disclaimer and have your employer sign it. Mail the signed disclaim to the SLIB maintainer. Contact jaffer @ ai.mit.edu for the address to mail the disclaimer to. Example: Company Copyright Disclaimer ------------------------------------- This disclaimer should be signed by a vice president or general manager of the company. If you can't get at them, anyone else authorized to license out software produced there will do. Here is a sample wording: EMPLOYER Corporation hereby disclaims all copyright interest in the program PROGRAM written by NAME. EMPLOYER Corporation affirms that it has no other intellectual property interest that would undermine this release, and will do nothing to undermine it in the future. SIGNATURE AND DATE, NAME, TITLE, EMPLOYER Corporation File: slib.info, Node: Index, Prev: About SLIB, Up: Top Procedure and Macro Index ************************* This is an alphabetical list of all the procedures and macros in SLIB. * Menu: * -: Multi-argument / and -. * -1+: Rev2 Procedures. * /: Multi-argument / and -. * 1+: Rev2 Procedures. * <=?: Rev2 Procedures. * <?: Rev2 Procedures. * =?: Rev2 Procedures. * >=?: Rev2 Procedures. * >?: Rev2 Procedures. * absolute-path?: System Interface. | * add-domain: Database Utilities. * add-process!: Multi-Processing. * add-setter: Setters. * adjoin: Lists as sets. * adjoin-parameters!: Parameter lists. * alarm: Multi-Processing. * alarm-interrupt: Multi-Processing. * alist->wt-tree: Construction of Weight-Balanced Trees. * alist-associator: Association Lists. * alist-for-each: Association Lists. * alist-inquirer: Association Lists. * alist-map: Association Lists. * alist-remover: Association Lists. * and?: Non-List functions. * any?: Collections. * append!: Rev2 Procedures. * apply: Multi-argument Apply. * array-1d-ref: Arrays. * array-1d-set!: Arrays. * array-2d-ref: Arrays. * array-2d-set!: Arrays. * array-3d-ref: Arrays. * array-3d-set!: Arrays. * array-copy!: Array Mapping. * array-dimensions: Arrays. * array-for-each: Array Mapping. * array-in-bounds?: Arrays. * array-index-map!: Array Mapping. * array-indexes: Array Mapping. * array-map!: Array Mapping. * array-rank: Arrays. * array-ref: Arrays. * array-set!: Arrays. * array-shape: Arrays. * array?: Arrays. * asctime: Posix Time. * ash: Bit-Twiddling. * atom?: Non-List functions. * batch:apply-chop-to-fit: Batch. * batch:call-with-output-script: Batch. * batch:comment: Batch. * batch:delete-file: Batch. * batch:initialize!: Batch. * batch:lines->file: Batch. * batch:rename-file: Batch. * batch:run-script: Batch. * batch:system: Batch. * batch:try-system: Batch. * bit-extract: Bit-Twiddling. * bit-field: Bit-Twiddling. * bitwise-if: Bit-Twiddling. * break: Breakpoints. * break-all: Debug. * breakf: Breakpoints. * breakpoint: Breakpoints. * browse: Database Browser. * browse-url-netscape: System Interface. | * butlast: Lists as sequences. * butnthcdr: Lists as sequences. * byte-ref: Byte. * byte-set!: Byte. * bytes: Byte. * bytes->list: Byte. * bytes-length: Byte. * call-with-dynamic-binding: Dynamic Data Type. * call-with-input-string: String Ports. * call-with-output-string: String Ports. * call-with-tmpnam: System Interface. | * call-with-values: Values. * capture-syntactic-environment: Syntactic Closures. * cart-prod-tables: Relational Database Operations. * catalog->html: HTML HTTP and CGI. | * catalog->page: HTML HTTP and CGI. | * cgi:read-query-string: HTML HTTP and CGI. * cgi:serve-command: HTML HTTP and CGI. * chap:next-string: Chapter Ordering. * chap:string<=?: Chapter Ordering. * chap:string<?: Chapter Ordering. * chap:string>=?: Chapter Ordering. * chap:string>?: Chapter Ordering. * check-parameters: Parameter lists. * close-base: Base Table. * close-database: Relational Database Operations. * close-table: Table Operations. * coerce: Non-List functions. * collection?: Collections. * combined-rulesets: Commutative Rings. * command->html: HTML HTTP and CGI. * continue: Breakpoints. * copy-bit: Bit-Twiddling. * copy-bit-field: Bit-Twiddling. * copy-list: List construction. * copy-random-state: Random Numbers. | * copy-tree: Tree Operations. * create-database <1>: Database Utilities. * create-database: Creating and Opening Relational Databases. * create-report: Database Reports. * create-table: Relational Database Operations. * create-view: Relational Database Operations. * cring:define-rule: Commutative Rings. * ctime: Posix Time. * current-directory: System Interface. | * current-error-port: Input/Output. * current-input-port <1>: Byte. * current-input-port: Ruleset Definition and Use. * current-output-port: Byte. * current-time: Time and Date. | * debug:breakf: Breakpoints. * debug:tracef: Trace. * debug:unbreakf: Breakpoints. * debug:untracef: Trace. * decode-universal-time: Common-Lisp Time. * define-access-operation: Setters. * define-operation: Yasos interface. * define-predicate: Yasos interface. * define-record: Structures. * define-syntax: Macro by Example. * define-tables: Database Utilities. * defmacro: Defmacro. * defmacro:eval: Defmacro. * defmacro:expand*: Defmacro. * defmacro:load: Defmacro. * defmacro?: Defmacro. * delete <1>: Destructive list operations. * delete: Base Table. * delete*: Base Table. * delete-domain: Database Utilities. * delete-file: Input/Output. * delete-if: Destructive list operations. * delete-if-not: Destructive list operations. * delete-table: Relational Database Operations. * dequeue!: Queues. * difftime: Time and Date. | * display-file: Line I/O. | * do-elts: Collections. * do-keys: Collections. * domain-checker: Database Utilities. * dynamic-ref: Dynamic Data Type. * dynamic-set!: Dynamic Data Type. * dynamic-wind: Dynamic-Wind. * dynamic?: Dynamic Data Type. * empty?: Collections. * encode-universal-time: Common-Lisp Time. * enquque!: Queues. * equal?: Byte. * eval: Eval. * every: Lists as sets. * every?: Collections. * extended-euclid: Modular Arithmetic. * factor: Prime Numbers. * file-exists?: Input/Output. * filename:match-ci??: Filenames. * filename:match??: Filenames. * filename:substitute-ci??: Filenames. | * filename:substitute??: Filenames. | * fill-empty-parameters: Parameter lists. * find-if: Lists as sets. * find-string-from-port?: String Search. * fluid-let: Fluid-Let. * for-each-elt: Collections. * for-each-key <1>: Collections. * for-each-key: Base Table. * for-each-row: Table Operations. * force-output: Input/Output. * format: Format Interface. * fprintf: Standard Formatted Output. * fscanf: Standard Formatted Input. * ftp-upload: System Interface. | * generic-write: Generic-Write. * gentemp: Defmacro. * get: Table Operations. * get*: Table Operations. * get-decoded-time: Common-Lisp Time. * get-method: Object. | * get-universal-time: Common-Lisp Time. * getenv: System Interface. * getopt: Getopt. * getopt--: Getopt. * getopt->arglist: Getopt Parameter lists. * getopt->parameter-list: Getopt Parameter lists. * glob-pattern?: System Interface. | * gmktime: Posix Time. * gmtime: Posix Time. * gtime: Posix Time. * has-duplicates?: Lists as sets. * hash: Hashing. * hash-associator: Hash Tables. * hash-for-each: Hash Tables. * hash-inquirer: Hash Tables. * hash-map: Hash Tables. * hash-remover: Hash Tables. * hashq: Hashing. * hashv: Hashing. * heap-extract-max!: Priority Queues. * heap-insert!: Priority Queues. * heap-length: Priority Queues. * home-vicinity: Vicinity. | * html:comment: HTML HTTP and CGI. * html:end-form: HTML HTTP and CGI. * html:end-page: HTML HTTP and CGI. * html:end-table: HTML HTTP and CGI. | * html:heading: HTML HTTP and CGI. | * html:href-heading: HTML HTTP and CGI. | * html:pre: HTML HTTP and CGI. | * html:start-form: HTML HTTP and CGI. * html:start-page: HTML HTTP and CGI. * html:start-table: HTML HTTP and CGI. | * http:read-request-line: HTML HTTP and CGI. * http:serve-query: HTML HTTP and CGI. * identifier=?: Syntactic Closures. * identifier?: Syntactic Closures. * identity: Legacy. * implementation-vicinity: Vicinity. * in-vicinity: Vicinity. * init-debug: Breakpoints. * integer-expt: Bit-Twiddling. * integer-length: Bit-Twiddling. * integer-sqrt: Root Finding. * interaction-environment: Eval. * intersection: Lists as sets. * jacobi-symbol: Prime Numbers. * kill-process!: Multi-Processing. * kill-table: Base Table. * laguerre:find-polynomial-root: Root Finding. * laguerre:find-root: Root Finding. * last: Lists as sequences. * last-pair: Legacy. * library-vicinity: Vicinity. * list*: List construction. * list->bytes: Byte. * list->string: Rev4 Optional Procedures. * list->vector: Rev4 Optional Procedures. * list-tail: Rev4 Optional Procedures. * load-option: Weight-Balanced Trees. * localtime: Posix Time. * logand: Bit-Twiddling. * logbit?: Bit-Twiddling. * logcount: Bit-Twiddling. * logior: Bit-Twiddling. * lognot: Bit-Twiddling. * logtest: Bit-Twiddling. * logxor: Bit-Twiddling. * macro:eval <1>: Syntax-Case Macros. * macro:eval <2>: Syntactic Closures. * macro:eval <3>: Macros That Work. * macro:eval: R4RS Macros. * macro:expand <1>: Syntax-Case Macros. * macro:expand <2>: Syntactic Closures. * macro:expand <3>: Macros That Work. * macro:expand: R4RS Macros. * macro:load <1>: Syntax-Case Macros. * macro:load <2>: Syntactic Closures. * macro:load <3>: Macros That Work. * macro:load: R4RS Macros. * macroexpand: Defmacro. * macroexpand-1: Defmacro. * macwork:eval: Macros That Work. * macwork:expand: Macros That Work. * macwork:load: Macros That Work. * make-: Structures. * make-array: Arrays. * make-atval: HTML HTTP and CGI. | * make-base: Base Table. * make-bytes: Byte. * make-command-server: Database Utilities. * make-directory: System Interface. | * make-dynamic: Dynamic Data Type. * make-generic-method: Object. | * make-generic-predicate: Object. | * make-getter: Base Table. * make-hash-table: Hash Tables. * make-heap: Priority Queues. * make-key->list: Base Table. * make-key-extractor: Base Table. * make-keyifier-1: Base Table. * make-list: List construction. * make-list-keyifier: Base Table. * make-method!: Object. | * make-object: Object. | * make-parameter-list: Parameter lists. * make-plain: HTML HTTP and CGI. | * make-port-crc: Cyclic Checksum. * make-predicate!: Object. | * make-promise: Promises. * make-putter: Base Table. * make-queue: Queues. * make-random-state: Random Numbers. * make-record-type: Records. * make-relational-system: Creating and Opening Relational Databases. * make-row-converter: HTML HTTP and CGI. | * make-ruleset: Commutative Rings. * make-shared-array: Arrays. * make-sierpinski-indexer: Hashing. * make-syntactic-closure: Syntactic Closures. * make-table: Base Table. * make-vicinity: Vicinity. * make-wt-tree: Construction of Weight-Balanced Trees. * make-wt-tree-type: Construction of Weight-Balanced Trees. * map-elts: Collections. * map-key: Base Table. * map-keys: Collections. * member-if: Lists as sets. * merge: Sorting. * merge!: Sorting. * mktime: Posix Time. * modular:: Modular Arithmetic. * modular:*: Modular Arithmetic. * modular:+: Modular Arithmetic. * modular:expt: Modular Arithmetic. * modular:invert: Modular Arithmetic. * modular:invertable?: Modular Arithmetic. * modular:negate: Modular Arithmetic. * modular:normalize: Modular Arithmetic. * modulus->integer: Modular Arithmetic. * must-be-first: Batch. * must-be-last: Batch. * nconc: Destructive list operations. * newton:find-root: Root Finding. * newtown:find-integer-root: Root Finding. * notany: Lists as sets. * notevery: Lists as sets. * nreverse: Destructive list operations. * nthcdr: Lists as sequences. * null-directory?: System Interface. | * null-environment: Eval. * object: Yasos interface. * object->limited-string: Object-To-String. * object->string: Object-To-String. * object-with-ancestors: Yasos interface. * object?: Object. | * offset-time: Time and Date. | * open-base: Base Table. * open-database <1>: Database Utilities. * open-database: Creating and Opening Relational Databases. * open-database!: Database Utilities. * open-table <1>: Relational Database Operations. * open-table: Base Table. * operate-as: Yasos interface. * or?: Non-List functions. * ordered-for-each-key: Base Table. * os->batch-dialect: Batch. * output-port-height: Input/Output. * output-port-width: Input/Output. * parameter-list->arglist: Parameter lists. * parameter-list-expand: Parameter lists. * parameter-list-ref: Parameter lists. * parse-ftp-address: System Interface. | * path->url: System Interface. | * plot!: Plotting. * position: Lists as sequences. * pprint-file: Pretty-Print. * pprint-filter-file: Pretty-Print. * prec:commentfix: Grammar Rule Definition. * prec:define-grammar: Ruleset Definition and Use. * prec:delim: Grammar Rule Definition. * prec:infix: Grammar Rule Definition. * prec:inmatchfix: Grammar Rule Definition. * prec:make-led: Nud and Led Definition. * prec:make-nud: Nud and Led Definition. * prec:matchfix: Grammar Rule Definition. * prec:nary: Grammar Rule Definition. * prec:nofix: Grammar Rule Definition. * prec:parse: Ruleset Definition and Use. * prec:postfix: Grammar Rule Definition. * prec:prefix: Grammar Rule Definition. * prec:prestfix: Grammar Rule Definition. * predicate->asso: Association Lists. * predicate->hash: Hash Tables. * predicate->hash-asso: Hash Tables. * present?: Base Table. * pretty-print: Pretty-Print. * prime?: Prime Numbers. * primes<: Prime Numbers. * primes>: Prime Numbers. * print: Yasos interface. * printf: Standard Formatted Output. * process:schedule!: Multi-Processing. * program-vicinity: Vicinity. * project-table: Relational Database Operations. * provide <1>: Require. * provide: Feature. * provided? <1>: Require. * provided?: Feature. * qp: Quick Print. * qpn: Quick Print. * qpr: Quick Print. * queue-empty?: Queues. * queue-front: Queues. * queue-pop!: Queues. * queue-push!: Queues. * queue-rear: Queues. * queue?: Queues. * random: Random Numbers. * random:exp: Random Numbers. * random:hollow-sphere!: Random Numbers. * random:normal: Random Numbers. * random:normal-vector!: Random Numbers. * random:solid-sphere!: Random Numbers. * random:uniform: Random Numbers. * rationalize: Rationalize. * read-byte: Byte. * read-command: Command Line. * read-line: Line I/O. * read-line!: Line I/O. * read-options-file: Command Line. * record-accessor: Records. * record-constructor: Records. * record-modifier: Records. * record-predicate: Records. * reduce <1>: Lists as sequences. * reduce: Collections. * reduce-init: Lists as sequences. * remove: Lists as sets. * remove-duplicates: Lists as sets. * remove-if: Lists as sets. * remove-if-not: Lists as sets. * remove-setter-for: Setters. * repl:quit: Repl. * repl:top-level: Repl. * replace-suffix: Filenames. * require <1>: Require. * require <2>: Catalog Compilation. * require: Requesting Features. * require:feature->path <1>: Require. * require:feature->path: Requesting Features. * restrict-table: Relational Database Operations. * row:delete: Table Operations. * row:delete*: Table Operations. * row:insert: Table Operations. * row:insert*: Table Operations. * row:remove: Table Operations. * row:remove*: Table Operations. * row:retrieve: Table Operations. * row:retrieve*: Table Operations. * row:update: Table Operations. * row:update*: Table Operations. * scanf: Standard Formatted Input. * scanf-read-list: Standard Formatted Input. * scheme-report-environment: Eval. * schmooz: Schmooz. * secant:find-bracketed-root: Root Finding. | * secant:find-root: Root Finding. | * seed->random-state: Random Numbers. | * serve-urlencoded-command: HTML HTTP and CGI. * set: Setters. * set-: Structures. * set-difference: Lists as sets. * Setter: Collections. * setter: Setters. * singleton-wt-tree: Construction of Weight-Balanced Trees. * size <1>: Collections. * size: Yasos interface. * slib:error: System. * slib:eval: System. * slib:eval-load: System. * slib:exit: System. * slib:load: System. * slib:load-compiled: System. * slib:load-source: System. * slib:report: Configuration. * slib:report-version: Configuration. * slib:warn: System. * software-type: Configuration. * some: Lists as sets. * sort: Sorting. * sort!: Sorting. * sorted?: Sorting. * soundex: Hashing. * sprintf: Standard Formatted Output. * sscanf: Standard Formatted Input. * string->list: Rev4 Optional Procedures. * string-capitalize: String-Case. * string-captialize!: String-Case. * string-ci->symbol: String-Case. * string-copy: Rev4 Optional Procedures. * string-downcase: String-Case. * string-downcase!: String-Case. * string-fill!: Rev4 Optional Procedures. * string-index: String Search. * string-index-ci: String Search. * string-join: Batch. * string-null?: Rev2 Procedures. * string-reverse-index: String Search. * string-reverse-index-ci: String Search. * string-subst: String Search. * string-upcase: String-Case. * string-upcase!: String-Case. * sub-vicinity: Vicinity. * subst: Tree Operations. * substq: Tree Operations. * substring-ci?: String Search. * substring-fill!: Rev2 Procedures. * substring-move-left!: Rev2 Procedures. * substring-move-right!: Rev2 Procedures. * substring?: String Search. * substv: Tree Operations. * supported-key-type?: Base Table. * supported-type?: Base Table. * symmetric:modulus: Modular Arithmetic. * sync-base: Base Table. * syncase:eval: Syntax-Case Macros. * syncase:expand: Syntax-Case Macros. * syncase:load: Syntax-Case Macros. * synclo:eval: Syntactic Closures. * synclo:expand: Syntactic Closures. * synclo:load: Syntactic Closures. * syntax-rules: Macro by Example. * system: System Interface. * table->html: HTML HTTP and CGI. | * table->page: HTML HTTP and CGI. | * table-exists?: Relational Database Operations. * table-name->filename: HTML HTTP and CGI. | * TAG: Structures. * tek40:draw: Tektronix Graphics Support. * tek40:graphics: Tektronix Graphics Support. * tek40:init: Tektronix Graphics Support. * tek40:linetype: Tektronix Graphics Support. * tek40:move: Tektronix Graphics Support. * tek40:put-text: Tektronix Graphics Support. * tek40:reset: Tektronix Graphics Support. * tek40:text: Tektronix Graphics Support. * tek41:draw: Tektronix Graphics Support. * tek41:encode-int: Tektronix Graphics Support. * tek41:encode-x-y: Tektronix Graphics Support. * tek41:graphics: Tektronix Graphics Support. * tek41:init: Tektronix Graphics Support. * tek41:move: Tektronix Graphics Support. * tek41:point: Tektronix Graphics Support. * tek41:reset: Tektronix Graphics Support. * time-zone: Time Zone. * tmpnam: Input/Output. * tok:char-group: Token definition. * topological-sort: Topological Sort. * trace: Trace. * trace-all: Debug. * tracef: Trace. * transcript-off: Transcripts. * transcript-on: Transcripts. * transformer: Syntactic Closures. * truncate-up-to: Batch. * tsort: Topological Sort. * two-arg:-: Multi-argument / and -. * two-arg:/: Multi-argument / and -. * two-arg:apply: Multi-argument Apply. * type-of: Non-List functions. * tz:params: Time Zone. * tzset: Time Zone. * unbreak: Breakpoints. * unbreakf: Breakpoints. * union: Lists as sets. * unmake-method!: Object. | * untrace: Trace. * untracef: Trace. * user-email-address: System Interface. | * user-vicinity: Vicinity. * values: Values. * variant-case: Structures. * vector->list: Rev4 Optional Procedures. * vector-fill!: Rev4 Optional Procedures. * with-input-from-file: With-File. * with-output-to-file: With-File. * write-base: Base Table. * write-byte: Byte. * write-database: Relational Database Operations. * write-line: Line I/O. * wt-tree/add: Basic Operations on Weight-Balanced Trees. * wt-tree/add!: Basic Operations on Weight-Balanced Trees. * wt-tree/delete: Basic Operations on Weight-Balanced Trees. * wt-tree/delete!: Basic Operations on Weight-Balanced Trees. * wt-tree/delete-min: Indexing Operations on Weight-Balanced Trees. * wt-tree/delete-min!: Indexing Operations on Weight-Balanced Trees. * wt-tree/difference: Advanced Operations on Weight-Balanced Trees. * wt-tree/empty?: Basic Operations on Weight-Balanced Trees. * wt-tree/fold: Advanced Operations on Weight-Balanced Trees. * wt-tree/for-each: Advanced Operations on Weight-Balanced Trees. * wt-tree/index: Indexing Operations on Weight-Balanced Trees. * wt-tree/index-datum: Indexing Operations on Weight-Balanced Trees. * wt-tree/index-pair: Indexing Operations on Weight-Balanced Trees. * wt-tree/intersection: Advanced Operations on Weight-Balanced Trees. * wt-tree/lookup: Basic Operations on Weight-Balanced Trees. * wt-tree/member?: Basic Operations on Weight-Balanced Trees. * wt-tree/min: Indexing Operations on Weight-Balanced Trees. * wt-tree/min-datum: Indexing Operations on Weight-Balanced Trees. * wt-tree/min-pair: Indexing Operations on Weight-Balanced Trees. * wt-tree/rank: Indexing Operations on Weight-Balanced Trees. * wt-tree/set-equal?: Advanced Operations on Weight-Balanced Trees. * wt-tree/size: Basic Operations on Weight-Balanced Trees. * wt-tree/split<: Advanced Operations on Weight-Balanced Trees. * wt-tree/split>: Advanced Operations on Weight-Balanced Trees. * wt-tree/subset?: Advanced Operations on Weight-Balanced Trees. * wt-tree/union: Advanced Operations on Weight-Balanced Trees. * wt-tree?: Basic Operations on Weight-Balanced Trees. Variable Index ************** This is an alphabetical list of all the global variables in SLIB. * Menu: * *catalog*: Require. * *features*: Require. * *html:output-port*: HTML HTTP and CGI. * *modules*: Require. * *optarg*: Getopt. * *optind*: Getopt. * *qp-width*: Quick Print. * *random-state*: Random Numbers. * *ruleset*: Commutative Rings. * *syn-defs*: Ruleset Definition and Use. * *syn-ignore-whitespace*: Ruleset Definition and Use. * *timezone*: Time Zone. * batch:platform: Batch. * catalog-id: Base Table. * char-code-limit: Configuration. * charplot:height: Plotting. * charplot:width: Plotting. * column-domains: Table Operations. * column-foreigns: Table Operations. * column-names: Table Operations. * column-types: Table Operations. * daylight?: Time Zone. * distribute*: Commutative Rings. * distribute/: Commutative Rings. * most-positive-fixnum: Configuration. * nil: Legacy. * number-wt-type: Construction of Weight-Balanced Trees. * primary-limit: Table Operations. * prime:prngs: Prime Numbers. * prime:trials: Prime Numbers. * slib:form-feed: Configuration. * slib:tab: Configuration. * stderr: Standard Formatted I/O. * stdin: Standard Formatted I/O. * stdout: Standard Formatted I/O. * string-wt-type: Construction of Weight-Balanced Trees. * t: Legacy. * tok:decimal-digits: Token definition. * tok:lower-case: Token definition. * tok:upper-case: Token definition. * tok:whitespaces: Token definition. * tzname: Time Zone. Concept and Feature Index ************************* * Menu: * alist: Association Lists. * alist-table <1>: Creating and Opening Relational Databases. * alist-table: Base Table. * ange-ftp: System Interface. | * array: Arrays. * array-for-each: Array Mapping. * attribute-value: HTML HTTP and CGI. * balanced binary trees: Weight-Balanced Trees. * batch: Batch. * binary trees: Weight-Balanced Trees. * binary trees, as discrete maps: Weight-Balanced Trees. * binary trees, as sets: Weight-Balanced Trees. * break: Breakpoints. * byte: Byte. * calendar time <1>: Posix Time. | * calendar time: Time and Date. | * Calendar-Time: Posix Time. * caltime: Posix Time. * careful: Commutative Rings. * catalog: Requesting Features. * Catalog File: Library Catalogs. * chapter-order: Chapter Ordering. * charplot: Plotting. * collect: Collections. * command line: Command Line. * commentfix: Precedence Parsing Overview. * common-list-functions <1>: Common List Functions. * common-list-functions: Collections. * commutative-ring: Commutative Rings. * Coordinated Universal Time: Posix Time. * database-utilities <1>: Database Utilities. * database-utilities: Batch. * debug <1>: Breakpoints. * debug: Debug. * defmacroexpand <1>: Pretty-Print. * defmacroexpand: Defmacro. * delim: Precedence Parsing Overview. * discrete maps, using binary trees: Weight-Balanced Trees. * dynamic: Dynamic Data Type. * dynamic-wind: Dynamic-Wind. * Euclidean Domain: Commutative Rings. * factor: Prime Numbers. * feature <1>: About this manual. * feature <2>: Requesting Features. * feature: Feature. * fluid-let <1>: Database Utilities. * fluid-let: Fluid-Let. * form: HTML HTTP and CGI. * format: Format. * generic-write: Generic-Write. * getit: System Interface. | * getopt <1>: Database Utilities. * getopt: Getopt. * glob <1>: Batch. * glob: Filenames. * hash: Hashing. * hash-table: Hash Tables. * HOME <1>: Vicinity. * HOME: Library Catalogs. * homecat: Catalog Compilation. * implcat: Catalog Compilation. * infix: Precedence Parsing Overview. * inmatchfix: Precedence Parsing Overview. * Left Denotation, led: Nud and Led Definition. * line-i: Line I/O. * logical: Bit-Twiddling. * macro <1>: Repl. * macro: R4RS Macros. * macro-by-example: Macro by Example. * macros-that-work: Macros That Work. * make-crc: Cyclic Checksum. * match: Base Table. * match-key: Base Table. * match-keys: Table Operations. * matchfix: Precedence Parsing Overview. * minimum field width (printf): Standard Formatted Output. * mkimpcat.scm: Catalog Compilation. * mklibcat.scm: Catalog Compilation. * modular: Modular Arithmetic. * multiarg-apply: Multi-argument Apply. * mutliarg: Multi-argument / and -. * nary: Precedence Parsing Overview. * net-clients: System Interface. | * nofix: Precedence Parsing Overview. * Null Denotation, nud: Nud and Led Definition. * object: Object. | * object->string: Object-To-String. * oop: Yasos. * option, run-time-loadable: Weight-Balanced Trees. * options file: Command Line. * package: Top. * packages: Top. * parameters <1>: Database Utilities. * parameters <2>: Batch. * parameters: Parameter lists. * parse: Precedence Parsing. * plain-text: HTML HTTP and CGI. * posix-time: Posix Time. * postfix: Precedence Parsing Overview. * pprint-file: Pretty-Print. * PRE: HTML HTTP and CGI. | * precedence: Precedence Parsing. * precision (printf): Standard Formatted Output. * prefix: Precedence Parsing Overview. * prestfix: Precedence Parsing Overview. * pretty-print: Pretty-Print. * primes: Prime Numbers. * printf: Standard Formatted Output. * priority-queue: Priority Queues. * PRNG: Random Numbers. * process: Multi-Processing. * promise: Promises. * qp <1>: Quick Print. * qp: Getopt. * query-string: HTML HTTP and CGI. * queue: Queues. * random: Random Numbers. * rationalize: Rationalize. * read-command: Command Line. * record: Records. * relational-database: Relational Database. * repl <1>: Repl. * repl: Syntax-Case Macros. * rev2-procedures: Rev2 Procedures. * rev3-report: Coding Standards. * rev4-optional-procedures: Rev4 Optional Procedures. * ring, commutative: Commutative Rings. * RNG: Random Numbers. * root: Root Finding. * run-time-loadable option: Weight-Balanced Trees. * scanf: Standard Formatted Input. * Scheme: Top. * schmooz: Schmooz. * session: Feature. * sets, using binary trees: Weight-Balanced Trees. * sierpinski: Hashing. * sitecat: Catalog Compilation. * SLIB: Top. * slibcat: Catalog Compilation. * sort: Sorting. * soundex: Hashing. * stdio: Standard Formatted I/O. * string-case: String-Case. * string-port: String Ports. * string-search: String Search. * struct: Structures. * syntactic-closures: Syntactic Closures. * syntax-case: Syntax-Case Macros. * time: Time and Date. | * time-zone: Time Zone. * topological-sort: Topological Sort. * trace: Trace. * transcript: Transcripts. * tree: Tree Operations. * trees, balanced binary: Weight-Balanced Trees. * tsort: Topological Sort. * TZ-string: Time Zone. * Uniform Resource Locator: System Interface. | * Unique Factorization: Commutative Rings. * usercat: Catalog Compilation. * UTC: Posix Time. * values: Values. * weight-balanced binary trees: Weight-Balanced Trees. * wild-card: Base Table. * with-file: With-File. * wt-tree: Weight-Balanced Trees. * yasos: Yasos. Tag Table: Node: Top Node: The Library System Node: Feature Node: Requesting Features Node: Library Catalogs Node: Catalog Compilation Node: Built-in Support Node: Require 10405 Node: Vicinity 12898 Node: Configuration 15865 Node: Input/Output 18806 Node: Legacy 20405 Node: System 21247 Node: About this manual 23739 Node: Scheme Syntax Extension Packages 24296 Node: Defmacro 24981 Node: R4RS Macros 26931 Node: Macro by Example 28186 Node: Macros That Work 31062 Node: Syntactic Closures 37120 Node: Syntax-Case Macros 54553 Node: Fluid-Let 58679 Node: Yasos 59620 Node: Yasos terms 60413 Node: Yasos interface 61437 Node: Setters 63512 Node: Yasos examples 66153 Node: Textual Conversion Packages 69625 Node: Precedence Parsing 70201 Node: Precedence Parsing Overview 70864 Node: Ruleset Definition and Use 73061 Node: Token definition 75442 Node: Nud and Led Definition 77711 Node: Grammar Rule Definition 80160 Node: Format 87734 Node: Format Interface 87982 Node: Format Specification 89719 Node: Standard Formatted I/O 99776 Node: Standard Formatted Output 100342 Node: Standard Formatted Input 109394 Node: Programs and Arguments 116053 Node: Getopt 116566 Node: Command Line 122408 Node: Parameter lists 125597 Node: Getopt Parameter lists 129234 Node: Filenames 131429 Node: Batch 134846 Node: HTML HTTP and CGI 142756 Node: Printing Scheme 152961 Node: Generic-Write 153284 Node: Object-To-String 154687 Node: Pretty-Print 155091 Node: Time and Date 157037 Node: Time Zone 158959 Node: Posix Time 168656 Node: Common-Lisp Time 170871 Node: Vector Graphics 172450 Node: Tektronix Graphics Support 172639 Node: Schmooz 174013 Node: Mathematical Packages 178239 Node: Bit-Twiddling 178794 Node: Modular Arithmetic 183385 Node: Prime Numbers 185519 Node: Random Numbers 186971 Node: Cyclic Checksum 193593 Node: Plotting 195303 Node: Root Finding 197878 Node: Commutative Rings 203071 Node: Determinant 214457 Node: Database Packages 214755 Node: Base Table 215019 Node: Relational Database 225177 Node: Motivations 225961 Node: Creating and Opening Relational Databases 231008 Node: Relational Database Operations 233440 Node: Table Operations 236237 Node: Catalog Representation 244115 Node: Unresolved Issues 247013 Node: Database Utilities 249964 Node: Database Reports 265619 Node: Database Browser 269443 Node: Weight-Balanced Trees 270504 Node: Construction of Weight-Balanced Trees 274374 Node: Basic Operations on Weight-Balanced Trees 277824 Node: Advanced Operations on Weight-Balanced Trees 280789 Node: Indexing Operations on Weight-Balanced Trees 286811 Node: Other Packages 290725 Node: Data Structures 291124 Node: Arrays 291883 Node: Array Mapping 294837 Node: Association Lists 296754 Node: Byte 299005 Node: Collections 301236 Node: Dynamic Data Type 307338 Node: Hash Tables 308599 Node: Hashing 310716 Node: Object 315570 Node: Priority Queues 333584 Node: Queues 334506 Node: Records 335632 Node: Structures 339143 Node: Procedures 340443 Node: Common List Functions 341130 Node: List construction 341554 Node: Lists as sets 343217 Node: Lists as sequences 348589 Node: Destructive list operations 353834 Node: Non-List functions 356497 Node: Tree Operations 357845 Node: Chapter Ordering 359391 Node: Sorting 361011 Node: Topological Sort 366788 Node: String-Case 368475 Node: String Ports 369096 Node: String Search 369860 Node: Line I/O 372227 Node: Multi-Processing 374820 Node: Standards Support 375903 Node: With-File 376558 Node: Transcripts 376834 Node: Rev2 Procedures 377155 Node: Rev4 Optional Procedures 378862 Node: Multi-argument / and - 379432 Node: Multi-argument Apply 380083 Node: Rationalize 380569 Node: Promises 381232 Node: Dynamic-Wind 381649 Node: Eval 382903 Node: Values 386240 Node: Session Support 387027 Node: Repl 387508 Node: Quick Print 388791 Node: Debug 389904 Node: Breakpoints 390546 Node: Trace 392764 Node: System Interface 394138 Node: Extra-SLIB Packages 401331 Node: About SLIB 403465 Node: Installation 403908 Node: Porting 405758 Node: Coding Standards 407309 Node: Copyrights 409387 Node: Index 412712 End Tag Table