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COM-AND Script Utility --------------------------------------- COM-AND Script Utility Script utility for the COM-AND language --------------------------------------- CACMP ver.1.2 and COM-AND are copyright by 1992 CABER Software. CACMP and COM-AND are distributed freely and may be copied by anyone for any number of machines, for purposes of evaluation. The author offers COM-AND and its accessory programs together as "shareware". If you USE the program you MUST pay for it. The complete user license and registration information is to be found in the file REGISTER.DOC. Limitations on redistribution of COM-AND are set out in the file VENDOR.DOC. These two files are included with the COM-AND program release. CABER Software R. (Scott) McGinnis P.O. Box 3607 Mdse Mart Chicago, IL 60654-0607 GEnie, Delphi: TARTAN CIS .......... 73147,2665 Internet ..... 73147.2665@compuserve.com Version 1.2: 921012 COM-AND Script Utility Table of Contents ----------------- I. Introduction .............................................. page 1 II. Running CACMP ............................................. page 2 III. CACMP functions ............................................ page 4 A. Syntax check ............................................ page 4 B. Semantic check .......................................... page 5 C. Partial strip ........................................... page 9 D. Full strip .............................................. page 10 E. Preprocessing ........................................... page 11 IV. CACMP and COM-AND .......................................... page 12 V. Program Requirements ....................................... page 13 VI. Program and Author Information ............................ page 14 Version 1.2: 921012 COM-AND Script Utility Page 1 I. Introduction A. What is COM-AND? COM-AND for the IBM PC and compatibles is a communications pro- gram for use by itself, or with several integrated accessory programs (which themselves may be used independently of COM-AND). COM-AND provides standard comm program functions: a dialing directory, macros, disk logging, binary and ASCII file transfers, ... and scripted execution. B. COM-AND scripts A script automates certain manual tasks, and allows COM-AND to run unattended (if the script has been tested (!!!)). A script is a program written to control COM-AND execution. Scripts distributed with COM-AND include: LEARN mode (a script that writes a script), a FILEMGR (perform DOS functions and find files for transmission), a BBS, a HOST mode, and many more. Script commands are read by COM-AND from an ASCII file (word processor files are not usually ASCII files (!)). COM-AND's internal editor (Alt-Q), programmer's text editors and EDLIN (included with DOS) may be used to create and modify a script file. C. The CACMP program CACMP is a diagnostic and preprocessor for COM-AND scripts. CACMP may be used simply to perform syntax and semantic review of a COM-AND script, or it may be used to preprocess scripts for COM-AND. This document discusses the use of CACMP.EXE. COM-AND scripts and the script language are discussed in the CASCRIPT.DOC document, distributed with COM-AND. Version 1.2: 921012 COM-AND Script Utility Page 2 II. Running CACMP Generally, CACMP is invoked at the DOS prompt with the command: ----------------------------------------------------------------- "d>" CACMP <options> [<infilename> [<outfilename>]] Where "d>" is the DOS prompt, and <options> are [<switch> [<switch> ...]] ----------------------------------------------------------------- CACMP could be invoked with a command such as: "d>" CACMP to simply start CACMP. In this case, CACMP prompts for an input file and does not write a stripped/preprocessed file. The command: "d>" CACMP /s causes CACMP to prompt for both an input AND an output file name (the input file MUST NOT be the same as the output file). Output is the input stripped of comments (see below). CACMP by default deletes an output file (if there is one) when a syntax error is found. This action may be inhibited with the switch "/k". In the case: "d>" CACMP /s/k the output file is retained (and lines marked as 'syntax errors' are retained (partially stripped, regardless of preprocessing). The input file name (and output file name) may be specified in the run command. For example: "d>" CACMP /s bbs.src reads the file BBS.SRC and prompts for an output file name. Input file names default to the extension ".CMD" if the name given is not found. The output file, if it exists, is deleted and recreated when CACMP begins. For this reason, CACMP must not be run with the same file as INPUT and output. Version 1.2: 921012 COM-AND Script Utility Page 3 II. Running CACMP (continued) The following switches are defined for CACMP at run-time: /1 Partial strip output (see below) /s Full strip output (see below) /k Keep output when syntax error is detected /p Preprocess script (for speed) The default settings for CACMP are: no output, and delete output if a syntax error is detected. All error and diagnostic output by CACMP is directed to the standard output device. Therefore, the command: "d>" CACMP >temp script.cmd records all the diagnostic information in the file TEMP on the cur- rent subdirectory, for later review. When CACMP terminates it displays the following summary: Total input lines: Total input statements: Total input comments: Total input labels: Total syntax errors: Total semantic warnings: If CACMP created an output file, CACMP also reports: Input file size: Output file size: CACMP terminates with a DOS error level of 0 if no syntax errors and no semantic errors are detected. CACMP terminates with a DOS error level of 1 if either syntax or semantic errors are reported. [Batch checks of a group of scripts may be stopped on an error using the error level returned to DOS.] Version 1.2: 921012 COM-AND Script Utility Page 4 III. CACMP functions A. Syntax check CACMP's first function is to syntactically verify each line of the input file. Syntax errors are noted as follows: Line 3: Syntax error S0 = N0+5(N1+ N2) ^ General parse failure (syntax) The first line records the line number and the error. The second line echoes the input line. The third line points to the highest point the parser reached parsing the line (probably close to the point at which the error occurs). The fourth line adds any addi- tional information returned by the parser. Developer's note: In the fourth line, ANY return except the one above should be reported to the author. The fourth line properly may be considered diagnostic to CACMP. For example, 'Stack overflow' at this point indicates that the parser recursed beyond its stack - a CACMP problem and not an input problem. All error and diagnostic information listed by CACMP is directed to the standard output device. Therefore, the command: "d>" CACMP >temp script.cmd records all CACMP diagnostic information in the file TEMP on the current subdirectory, for later review. Syntax errors are counted, and the number reported at CACMP ter- mination. If CACMP is used to strip/preprocess a file and syntax errors are detected, the output file is deleted (unless /k in the run command is specified). Version 1.2: 921012 COM-AND Script Utility Page 5 III. CACMP functions (continued) B. Semantic check Beyond syntactic verification of each line, CACMP follows the input file to verify the structure of the script. Semantic verification in CACMP consists of: 1. Overlapped domains The IF, SWITCH, WHILE, FOR and DO statements imply a 'domain' of execution. The domain of the IF statement extends until an ENDIF statement (except in compound IF statements, where a single statement to be executed (when the condition is true) is carried on the same line). The domain of a SWITCH statement extends until an ENDSWITCH. Similarly the WHILE, FOR and DO statements domains extend until their respective terminators. Domains may NOT overlap. For example, the following construction is an overlapped domain: WHILE N0 LT 5 IF N0 EQ 3 ENDWHILE GOTO somewhere ENDIF ENDWHILE [In the above case, the ENDWHILE within the IF domain is superfluous (the WHILE loop domain would terminate on the GOTO).] CACMP diagnoses this code as: Line 3: WARNING: Overlapped domain ENDWHILE ^ ....... Current domain is IF starting: 2 The ENDWHILE on line 3 overlaps the IF domain that began in line 2. Version 1.2: 921012 COM-AND Script Utility Page 6 III. CACMP functions (continued) B. Semantic check (continued) 2. Incomplete domain On completion of processing, domains left open (i.e. with- out closure) are reported as 'incomplete domains' by CACMP. For example: WARNING: Incomplete WHILE domain starting: 1 In this case, a WHILE loop was not properly closed with an ENDWHILE. The WHILE statement is in line 1. 3. Unreachable code The GOTO, RETURN, FRETURN, ACCESSORY, EXECUTE, EXIT, BYE, TERMINAL, CONNECT, and QUIT statements are unconditional transfers of control. They do not return. When one of these statements is found OUTSIDE of the domain of an IF, WHILE, SWITCH, FOR, or DO statement, CACMP expects to find a label as the next executable statement. If not, CACMP issues the following semantic warning: Line 2: WARNING: Cannot reach this statement N0 = N0+1 ^ 4. Duplicate labels CACMP keeps track of label statements. When a label dupli- cates one previously seen, CACMP issues the warning: Line 9: WARNING: Duplicate label label: ^ Note that the label has been truncated to 8 characters. COM-AND only uses the first 8 characters of a label. Dupli- cation of the first 8 characters is often the root of a duplicate label condition. Version 1.2: 921012 COM-AND Script Utility Page 7 III. CACMP functions (continued) B. Semantic check (continued) 5. Undefined labels CACMP also keeps track of label used in GOTO, GOSUB, ON and WOPEN statements. On completion of processing, any label referenced by one of these statements but not found in the script is reported as 'undefined label'. For example: WARNING: Undefined label: SOMEWHER 6. Label in domain (IF/SWITCH/WHILE/FOR/DO) Above, it is noted that a GOTO terminates the 'domain' of an IF, SWITCH, WHILE, FOR, and DO statement. GOTOs may NOT transfer control INTO the domain of one of these statements. When a label is encountered within a domain, CACMP reports: Line 8: WARNING: Label in WHILE domain starting: 3 label: ^ It will be noted (painfully), that a single unclosed domain (for example, an IF missing its ENDIF) results in MANY 'label in domain' warnings. The clue in this case is that all errors reference a domain beginning on the same line. Correct the unclosed domain, and improper 'label in domain' warnings will disappear. Version 1.2: 921012 COM-AND Script Utility Page 8 III. CACMP functions (continued) B. Semantic check (continued) 7. COM-AND stack overflow COM-AND allows IF, WHILE, SWITCH, FOR and DO statements to be nested to a depth of 20. When CACMP finds a nesting level greater than 20 it issues a warning: WARNING: DO/FOR/IF/SWITCH/WHILE stack overflow WHILE 1 EQ 1 ^ 8. COM-AND stack underflow When an ENDIF, ENDWHILE, ENDSWITCH, ENDFOR or UNTIL statement is encountered with no corresponding start-of-domain state- ment, CACMP issues the warning: WARNING: DO/FOR/IF/SWITCH/WHILE stack underflow ENDWHILE ^ Version 1.2: 921012 COM-AND Script Utility Page 9 III. CACMP functions (continued) C. Partial strip When CACMP is run with the /1 switch, records of the input file are 'partially stripped' and written to the output file. Partial stripping is similar in function to the STRIPPER.CMD script once distributed with COM-AND. Partial stripping consists of: 1) Removal of comment lines 2) Removal of comments on statement lines 3) Removal of all blanks to the left of a statement 4) Reduction of multiple blanks to a single blank 5) Removal of redundant blanks (e.g. " = " -> "=") The STRIPPER.CMD script only performs function (1) above. Addi- tionally, CACMP writes the output file records with only a car- riage return (not carriage return/line feed), as COM-AND needs only the carriage return. A file 'partially stripped' by CACMP is smaller than one stripped by STRIPPER. The actual reduction in size is determined by the input file, but CACMP necessarily produces a smaller file. Please note that once stripped by CACMP, a file may not be 'read- able' by the same editor that produced its source. Some editors tolerate the missing line feed, and some don't. The popular LIST program by Vern Buerg, for example, won't display the file (except as a hex dump). Lines marked as 'syntax errors' are written to the output file partially stripped. Version 1.2: 921012 COM-AND Script Utility Page 10 III. CACMP functions (continued) D. Full Strip When CACMP is run with the /s switch, records of the input file are 'fully stripped' and written to the output file. Full stripping includes the functions listed above as 'partial stripping', and: 1) Reduction of label lines to an 8 character maximum 2) Reduction of labels in GOTO, GOSUB, ON and WOPEN statements to an 8 character maximum 3) Reduction of initial keywords in statements to a four character maximum. Again, CACMP writes the output file records with only a carriage return (not carriage return/line feed) as COM-AND needs only the carriage return. A file 'fully stripped' by CACMP is considerably smaller than one stripped by STRIPPER. The actual reduction in size is determined by the input file. [Your mileage may vary; contents are shipped by weight, not volume...] Lines marked 'syntax errors' are written to the output file, but only partially stripped. [Tricky ones in the audience might propose that labels be con- verted to numeric equivalents. After all, "1:" is a legitimate label. However, the COM-AND language supports indirect GOTOs. For example, "GOTO S0" branches to the label in S0 (given that S0 contains a valid label name). Therefore, such a reduction, although generally possible, is not supported.] Version 1.2: 921012 COM-AND Script Utility Page 11 III. CACMP functions (continued) E. Preprocessing When CACMP is run with the /P switch, records of the input file are 'preprocessed' and written to the output file. Preprocessing performs the full strip as described above, and: . adds a two byte keyword to each executable line to speed COM-AND's execution of the statement Preprocessed scripts are accepted by COM-AND as of its version 2.7. The two-byte code added to each executable line speeds the interpretor's execution of the statement. [Author's note: the two byte keyword may easily be recognized - the first byte is always negative (larger than 127).] A file 'preprocessed' by CACMP is larger than one stripped by CACMP. It executes approximately 30% faster than the same script stripped by CACMP. [Please note, preprocessing does not have any effect on writes to screen or disc. It simply speeds the interpretation of script statements.] Lines marked 'syntax errors' are written to the output file, but only partially stripped. They are not preprocessed. Version 1.2: 921012 COM-AND Script Utility Page 12 IV. CACMP and COM-AND CACMP implements a parser based upon a meta-language specification of the COM-AND language. COM-AND does not; its interpretor parses ad hoc (or if you wish, on-the-fly). The advantages of ad hoc interpretation are: 1) execution speed, and 2) simplicity of extension The disadvantage of ad hoc interpretation is that a syntax/semantic utility such as CACMP is not possible (not based on the interpretor's code, at least). The important point is that CACMP may kick out perfectly valid statements because its meta-language statement of the language does not accommodate a particular construction. COM-AND executes the statement happily, but CACMP rejects it. The language syntax implemented is taken from version 2.8 COM-AND documentation... however, COM-AND proper (not its documentation) is the final arbiter of syntax (and documentation is adjusted accordingly <smile>). If you use this, please save doubtful reports and submit them to the developer. Such reports are used to further refine CACMP. For the curious, the meta-language implemented here is similar in form to the LANGPACK language developed at Bell Labs. LANGPACK per se was not implemented - a modified Backus-Naur form for the meta- language was implemented in a lexical compiler created for CACMP. The parser CACMP implements uses the lexical compiler's output to control text parsing. Version 1.2: 921012 COM-AND Script Utility Page 13 V. Program requirements CACMP is written for an IBM PC or DOS compatible machine. CACMP uses DOS and BIOS for all I/O... no fancy games with screen buffers are played. COM-AND disk I/O is done through the 'Handle' oriented I/O routines added to DOS 2.0. Therefore DOS 2.0 is a minimum requirement. CACMP (Version 1.2) requires 110K for itself. You need 256K to take advantage of it. COM-AND requires 384k to be useful. Version 1.2: 921012 COM-AND Script Utility Page 14 VI. Author information CACMP was written using Microsoft Macro-Assembler. The author likes assembler. Assembly language is an entirely appropriate vehicle for some of the program, and a not-inappropriate vehicle for the rest of it. Everything, in moderation... The author of this program is R. Scott McGinnis of Chicago, IL. GEnie and Delphi id: TARTAN. CIS id: 73147,2665. Comment and suggestions (and criticism in moderation) are welcomed: CABER Software R. (Scott) McGinnis P.O. Box 3607 Mdse Mart Chicago, IL 60654-0607 I thank my wife, Elizabeth, who put up with my obsessing while I developed the parser on which CACMP is based. The meta-language specification of a language the size of COM-AND's is an obsessive task - writing a compiler to compile the meta-language and a parser to execute the compiler's output... the mind is a terrible thing to lose. Elizabeth refreshes this one every day. This program may be distributed freely (but it isn't a whole lot of use without COM-AND). Any problems that are reported to the author gets attention. COM-AND is shareware. If COM-AND is USED after a 30 day period of evaluation, you MUST pay for it. CACMP is included in the license to use COM-AND. [Please read REGISTER.DOC.] Version 1.2: 921012