Resource Library: Multimedia

home *** CD-ROM | disk | FTP | other *** search

/ Resource Library: Multimedia / Resource Library: Multimedia.iso / sgml / msdos / sgmls08 / sgmls.doc < prev next >

Wrap

Text File | 1992-05-11 | 21.1 KB | 595 lines

SGMLS(1) SGMLS(1) NAME sgmls - a validating SGML parser An SGML System Conforming to International Standard ISO 8879 -- Standard Generalized Markup Language SYNOPSIS sgmls [ -acdeglrsuv ] [ -ffile ] [ -iname ] filename... DESCRIPTION Sgmls parses and validates the SGML document entity in filename... and prints on the standard output a simple ASCII representation of its Element Structure Information Set. (This is the information set which a structure- controlled conforming SGML application should act upon.) The following options are available: -a Detect and report ambiguous content models. -c Describe capacity usage at the end of the parse. -d Warn about duplicate entity declarations. -e Describe open entities in error messages. Error messages always include the position of the most recently opened external entity. -ffile Redirect errors to file. -g Show the GIs of open elements in error messages. -iname Pretend that <!ENTITY % name INCLUDE> occurs at the start of the document type declara- tion subset in the SGML document entity. Since repeated definitions of an entity are ignored, this definition will take precedence over any other def- initions of this entity in the document type decla- ration. Multiple -i options are allowed. If the SGML declaration replaces the reserved name INCLUDE then the new reserved name will be the replacement text of the entity. Typically the document type declaration will contain <!ENTITY % name IGNORE> and will use %name; in the status keyword specifi- cation of a marked section declaration. In this case the effect of the option will be to cause the marked section not to be ignored. 1 SGMLS(1) SGMLS(1) -l Output L commands giving the current line number and filename. -p Parse only the prolog. Sgmls will exit after pars- ing the document type declaration. Implies -s. -r Warn about defaulted references. -s Suppress output. Error messages will still be printed. -u Warn about undefined element: elements used in the DTD but not defined. -v Print the version number. Entity Manager An external entity resides in one or more files. The entity manager component of sgmls maps a sequence of files into an entity in three sequential stages: 1. each carriage return character is turned into a non-SGML character; 2. each newline character is turned into a record end character, and at the same time a record start character is inserted at the beginning of each line; 3. the files are concatenated. A system identifier is interpreted as a list of filenames separated by semi-colons. If no system identifier is sup- plied, then the entity manager will attempt to generate a filename using the public identifier (if there is one) and other information available to it. Notation identifiers are not subject to this treatment. This process is con- trolled by the environment variable SGML_PATH; this con- tains a semicolon-separated list of filename templates. A filename template is a filename that may contain substitu- tion fields; a substitution field is a % character fol- lowed by a single letter that indicates the value of the substitution. If SGML_PATH uses the %S field (the value of which is the system identifier), then the entity man- ager will also use SGML_PATH to generate a filename when a system identifier that does not contain any semi-colons is supplied. The value of a substitution can either be a string or it can be null. The entity manager transforms the list of filename templates into a list of filenames by substituting for each substitution field and discarding any template that contained a substitution field whose value was null. It then uses the first resulting filename that exists and is readable. Substitution values are transformed before being used for substitution: firstly, 2 SGMLS(1) SGMLS(1) any names that were subject to upper case substitution are folded to lower case; secondly, the characters +,./:=? and space characters are deleted. The value of the %S field is not transformed. The values of substitution fields are as follows: %% A single %. %D The entity's data content notation. This substitu- tion will succeed only for external data entities. %N The entity, notation or document type name. %P The public identifier if there was a public identi- fier, otherwise null. %S The system identifier if there was a system identi- fier otherwise null. %X (This is provided mainly for compatibility with ARCSGML.) A three-letter string chosen as follows: | | | | With public identifier | +-------------+----------- | No public | Device | Device | identifier | independent | dependent ---------------------------+------------+-------------+----------- Data or subdocument entity | nsd | pns | vns General SGML text entity | gml | pge | vge Parameter entity | spe | ppe | vpe Document type definition | dtd | pdt | vdt Link process definition | lpd | plp | vlp The device dependent version is selected if the public text class allows a public text display ver- sion but no public text display version was speci- fied. %Y The type of thing for which the filename is being generated: SGML subdocument entity sgml Data entity data General text entity text Parameter entity parm Document type definition dtd Link process definition lpd The value of the following substitution fields will be null unless a valid formal public identifier was supplied. %A Null if the text identifier in the formal public identifier contains an unavailable text indicator, otherwise the empty string. 3 SGMLS(1) SGMLS(1) %C The public text class, mapped to lower case. %E The public text designating sequence (escape sequence) if the public text class is CHARSET, oth- erwise null. %I The empty string if the owner identifier in the formal public identifier is an ISO owner identi- fier, otherwise null. %L The public text language, mapped to lower case, unless the public text class is CHARSET, in which case null. %O The owner identifier (with the +// or -// prefix stripped.) %R The empty string if the owner identifier in the formal public identifier is a registered owner identifier, otherwise null. %T The public text description. %U The empty string if the owner identifier in the formal public identifier is an unregistered owner identifier, otherwise null. %V The public text display version. This substitution will be null if the public text class does not allow a display version or if no version was speci- fied. If an empty version was specified, a value of default will be used. System declaration The system declaration for sgmls is as follows: SYSTEM "ISO 8879-1986" CHARSET BASESET "ISO 646-1983//CHARSET International Reference Version (IRV)//ESC 2/5 4/0" DESCSET 0 128 0 CAPACITY PUBLIC "ISO 8879-1986//CAPACITY Reference//EN" FEATURES MINIMIZE DATATAG NO OMITTAG YES RANK NO SHORTTAG YES LINK SIMPLE NO IMPLICIT NO EXPLICIT NO OTHER CONCUR NO SUBDOC YES 1 FORMAL YES SCOPE DOCUMENT SYNTAX PUBLIC "ISO 8879-1986//SYNTAX Reference//EN" SYNTAX PUBLIC "ISO 8879-1986//SYNTAX Core//EN" VALIDATE GENERAL YES MODEL YES EXCLUDE YES CAPACITY YES NONSGML YES SGML YES FORMAL YES SDIF 4 SGMLS(1) SGMLS(1) PACK NO UNPACK NO The memory usage of sgmls is not a function of the capac- ity points used by a document; however, sgmls can handle capacities significantly greater than the reference capac- ity set. In some environments, higher values may be supported for the SUBDOC parameter. Documents that do not use optional features are also sup- ported. For example, if FORMAL NO is specified in the SGML declaration, public identifiers will not be required to be valid formal public identifiers. Certain parts of the concrete syntax may be changed: The shunned character numbers can be changed. Uppercase substitution can be performed or not per- formed both for entity names and for other names. Either short reference delimiters assigned by the reference delimiter set or no short reference delimiters are supported. The reserved names can be changed. The quantity set can be increased within certain limits subject to there being sufficient memory available. The upper limit on NAMELEN is 239. The upper limits on ATTCNT, ATTSPLEN, BSEQLEN, ENTLVL, LITLEN, PILEN, TAGLEN, and TAGLVL are more than thity times greater than the reference limits. The upper limit on GRPCNT, GRPGTCNT, and GRPLVL is 253. NORMSEP cannot be changed. DTAGLEN are DTEMPLEN irrelevant since sgmls does not support the DATATAG feature. Ambiguous content models are reported (as specified by MODEL YES) only if the -a option is given. SGML declaration The SGML declaration may be omitted, the following decla- ration will be implied: <!SGML "ISO 8879-1986" CHARSET BASESET "ISO 646-1983//CHARSET International Reference Version (IRV)//ESC 2/5 4/0" DESCSET 0 9 UNUSED 9 2 9 11 2 UNUSED 13 1 13 5 SGMLS(1) SGMLS(1) 14 18 UNUSED 32 95 32 127 1 UNUSED CAPACITY PUBLIC "ISO 8879-1986//CAPACITY Reference//EN" SCOPE DOCUMENT SYNTAX PUBLIC "ISO 8879-1986//SYNTAX Reference//EN" FEATURES MINIMIZE DATATAG NO OMITTAG YES RANK NO SHORTTAG YES LINK SIMPLE NO IMPLICIT NO EXPLICIT NO OTHER CONCUR NO SUBDOC YES 99999999 FORMAL YES APPINFO NONE> with the exception that characters 128 through 254 will be assigned to DATACHAR. When exporting documents that use characters in this range, an accurate description of the upper half of the document character set should be added to this declaration. For ISO Latin-1, an appropriate description would be: BASESET "ISO Registration Number 100//CHARSET ECMA-94 Right Part of Latin Alphabet Nr. 1//ESC 2/13 4/1" DESCSET 128 32 UNUSED 160 95 32 255 1 UNUSED Output format The output is a series of lines. Lines can be arbitrarily long. Each line consists of an initial command character and one or more arguments. Arguments are separated by a single space, but when a command takes a fixed number of arguments the last argument can contain spaces. There is no space between the command character and the first argu- ment. Arguments can contain the following escape sequences. \\ A \. \n A record end character. \| Internal SDATA entities are bracketed by these. \nnn The character whose code is nnn octal. \s A space. This is used only in filenames or nota- tion identifiers that contain a space. (Filenames can occur in the S, E and L commands.) The possible command characters and arguments are as fol- lows: (gi The start of an element whose generic identifier is gi. Any attributes for this element will have been specified with A commands. )gi The end an element whose generic identifier is gi. 6 SGMLS(1) SGMLS(1) -data Data. &name A reference to an external data entity name; name will have been defined using an E command. ?pi A processing instruction with data pi. Aname val The next element to start has an attribute name with value val which takes one of the following forms: IMPLIED The value of the attribute is implied. CDATA data The attribute is character data. This is used for attributes whose declared value is CDATA. TOKEN token... The attribute is a list of tokens. This is used for attributes whose declared value is a name token group or one of NAME, NMTOKEN, NUTOKEN, NUMBER, NAMES, NMTOKENS, NUTOKENS or NUMBERS. NOTATION nname The attribute is a notation name; nname will have been defined using a N command. This is used for attributes whose declared value is NOTATION. ENTITY name... The attribute is a list of general entity names. Each entity name will have been defined using an I, E or S command. This is used for attributes whose declared value is ENTITY or ENTITIES. ID id The attribute is an id value. This is used for attributes whose declared value is ID. IDREF id... The attribute is a list of id references. This is used for attributes whose declared value is IDREF or IDREFS. Dename name val This is the same as the A command, except that it specifies a data attribute for an external entity named ename. Any D commands will come after the E command that defines the entity to which they apply, but before any & or A commands that 7 SGMLS(1) SGMLS(1) reference the entity. Nnname sysid pubid Define a notation nname associated with system identifier sysid, and public identifier pubid. If no system identifier was specified, the notation name will be used (after being transformed as if it were a substitution value). If no public identi- fier was specified, pubid will be omitted. A nota- tion will only be defined if it is to be referenced in an E command or in an A command for an attribute with a declared value of NOTATION. Eename typ nname filename... Define an external data entity named ename with type typ (CDATA, NDATA or SDATA), notation not and a list of files filename...; not will have been defined using a N command. Data attributes may be specified for the entity using D commands. An external data entity will only be defined if it is to be referenced in a & command or in an A command for an attribute whose declared value is ENTITY or ENTITIES. Iename typ text Define an internal data entity named ename with type typ (CDATA or SDATA) and entity text text. An internal data entity will only be defined if it is referenced in an A command for an attribute whose declared value is ENTITY or ENTITIES. Sename filename... Define a subdocument entity with a list of files filename.... Such an entity will only be defined if it is referenced in an A command for an attribute whose declared value is ENTITY or ENTI- TIES. {ename The start of the SGML subdocument entity ename. }ename The end of the SGML subdocument entity ename. Llineno file Llineno Set the current line number and filename. The filename argument will be omitted if only the line number has changed. This will be output only if the -l option has been given. #text An APPINFO parameter of text was specified in the SGML declaration. This is not strictly part of the ESIS, but a structure-controlled application is permitted to act on it. No # command will be out- put if APPINFO NONE was specified. A # command 8 SGMLS(1) SGMLS(1) will occur at most once, and may be preceded only by a single L command. BUGS Non-SGML characters in literals are counted as two charac- ters for the purposes of quantity and capacity calcula- tions. No error message is given for character references or marked section declarations between the end of the DTD and the start of the document element. SEE ALSO The SGML Handbook, Charles F. Goldfarb ISO 8879 (Standard Generalized Markup Language), Interna- tional Organization for Standardization ORIGIN ARCSGML was written by Charles F. Goldfarb. Sgmls was derived from ARCSGML by James Clark (jjc@jclark.com), to whom bugs should be reported. 9