%option noyywrap outfile="simple_lexer.c"
/* scanner for a toy calculator                                    simple_lexer.l  */
%{
#include "Expr.h"                       /* required for the types in next line */
#include "simple_parser.tab.h"          /* token definitions and types */
%}
%%
[0-9]+               yylval.intval = atoi(yytext); return TOK_NUMBER;
if                       return TOK_IF;
then                  return TOK_THEN;
else                   return TOK_ELSE;
[a-z][a-z0-9]*   yylval.string = strdup(yytext); return TOK_ID;
[ \t]+                   /* eat up whitespace */
[+\-*/()\n]           { return yytext[0];}
.                        fprintf(stderr, "Unrecognized character: %s\n", yytext ); return -1;