%{
// This is for UCSD CSE 141L, Spring 2006.  -Wei and JSampson
// 
// documentation on flex found in:
//
// http://www.gnu.org/software/flex/manual/html_mono/flex.html
//

// This is a source file for GNU flex.  Flex compiles this file
// into a text processing tool using the grammar specified below.  
// Run flex as to generate lex.yy.c:
// > flex sample_lex.l
//
// The makefile adds an option to rename the generated output file.
// 
// The generated lex.yy.c will provide an API to recognize 
// certain strings.  See further comments below


#include <stdio.h>
#include <stdlib.h>
#include "token.h"
int size;	


// The following definitions specifies regular expressions.  Regular 
// expressions are patterns that may match a given string, indicating 
// some action is to be taken.  The action may communicate things like 
// what is it classified as, along with other information. 

// Everything between %{ and %} are directly passed to lex.yy.c
%}

ws      [ \t]+
token   [a-zA-Z][a-zA-Z0-9_\-]*
comment \#[^\n]+

%%


\n	        { /* This section contains several "rules" consisting of an
                   * a "pattern" and "action".  If an input string matches
                   * the pattern, then the action executes, often passing
                   * this information externally.  In this actions you can see that
                   * it return a macro defined NEWLINE (see token.h). This is
                   * used in parser.C to count line numbers.
                   * The matched string is visible externally as yytext variable.
                   */
                  return NEWLINE; }
{ws}	
{comment}	
{token}:	{ size = strlen(yytext); yytext[size-1]=0; return LABEL; }
{token}		{ return TOKEN; }

%%