README

JLexPHP: a Lexical Analyzer Generator for PHP, based on JLex.
For copyright and licensing information, see the COPYING file.

This is an adaptation of some Java code that generates lexers from lex style
input files.

The porting effort was pretty trivial, with the hardest part being the buffer management.

Usage is fairly typical of lexers; you'll want to create a lexer file like this:

----8<------
<?php
include 'jlex.php';

%%

D = [0-9]

%%

D+ { echo "The number ", $this->yytext(), "\n"; }
.  { echo "Something else ", $this->yytext(), "\n"; }

----8<------

Then run process this file:

  java -cp JLexPHP.jar JLexPHP.Main your.lex

(the supplied makefile will create the jar file for you, or you
can build it with:

  javac JLexPHP/Main.java
  jar cvf JLexPHP.jar JLexPHP/*.class
)

JLexPHP will output your.lex.php.  It will contain a class that will recognize
the input stream described in your .lex file.

Usage of that class is along the lines of:

$scanner = new Yylex(fopen("file", "r"));
while ($scanner->yylex())
	;

A more complicated scanner will use the createToken() method to create a token
object that can then be fed into a parser, such as a lemon based parser.  You
can see an example of that in the c.lex source file.  It is designed to work in
conjunction with it's corresponding c.y file in my lemon port for php.


You can find more information on the lexer syntax in the JLex manual:
http://www.cs.princeton.edu/~appel/modern/java/JLex/current/manual.html


Enjoy!

--Wez.
progminer / jlex-php-lib

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