plex(1)
NAME
plex - The Pascal Lex lexical analyzer generator.
USAGE
lex [options] lex-file[.l] [output-file[.pas]]
OPTIONS
- -v Verbose: Lex generates a readable description of
- the generated lexical analyzer, written to lex-file with new ex
- tension .lst
- -o Optimize: Lex optimizes DFA tables to produce a
- minimal DFA.
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 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 rou
- tine, yylex, implemented as:
function yylex : Integer;- This routine has to be called by your main program to exe
- cute 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 con
- structs 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 pro
- vides various useful utility routines; see the file lexlib.pas
- for further information.
MORE INFORMATION
- For more information, see the documentation that comes
- with TP lex and yacc.
AUTHOR
- Albert Graeff (<ag@muwiinfa.geschichte.uni-mainz.de>,
- <Dr.Graef@t-online.de>)