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- .TH plex 1 "10 Jan 2000" "Free Pascal" "Pascal lexical analyzer generator"
- .SH NAME
- plex \- The Pascal Lex lexical analyzer generator.
- .SH USAGE
- .B lex [options] lex-file[.l] [output-file[.pas]]
- .SH OPTIONS
- .TP
- .B \-v
- .I Verbose:
- Lex generates a readable description of the generated
- lexical analyzer, written to lex-file with new extension
- .I .lst
- .TP
- .B \-o
- .I Optimize:
- Lex optimizes DFA tables to produce a minimal DFA.
- .SH DESCRIPTION
- TP Lex is a program generator that is used to generate the Turbo Pascal source
- code for a lexical analyzer subroutine from the specification of an input
- language by a regular expression grammar.
- TP Lex parses the source grammar contained in lex-file (with default suffix
- .l) and writes the constructed lexical analyzer subroutine to the specified
- output-file (with default suffix .pas); if no output file is specified, output
- goes to lex-file with new suffix .pas. If any errors are found during
- compilation, error messages are written to the list file (lex-file with new
- suffix .lst).
- The generated output file contains a lexical analyzer routine, yylex,
- implemented as:
- .RS
- function yylex : Integer;
- .RE
- This routine has to be called by your main program to execute the lexical
- analyzer. The return value of the yylex routine usually denotes the number
- of a token recognized by the lexical analyzer (see the return routine in the
- LexLib unit). At end-of-file the yylex routine normally returns 0.
- The code template for the yylex routine may be found in the yylex.cod
- file. This file is needed by TP Lex when it constructs the output file. It
- must be present either in the current directory or in the directory from which
- TP Lex was executed (TP Lex searches these directories in the indicated
- order). (NB: For the Linux/Free Pascal version, the code template is searched
- in some directory defined at compile-time instead of the execution path,
- usually /usr/lib/fpc/lexyacc.)
- The TP Lex library (LexLib) unit is required by programs using Lex-generated
- lexical analyzers; you will therefore have to put an appropriate uses clause
- into your program or unit that contains the lexical analyzer routine. The
- LexLib unit also provides various useful utility routines; see the file
- lexlib.pas for further information.
- .SH MORE INFORMATION
- For more information, see the documentation that comes with TP lex and yacc.
- .SH AUTHOR
- Albert Graeff (<[email protected]>, <[email protected]>)
- .SH SEE ALSO
- .BR ppc386 (1)
- .BR pyacc (1)
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