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Author: John Gunderman
This file contains a lexical analyzer for
a C-like compiler.
#include <stdio.h>
#include <string.h>
#include "hash_tables.h"
if yywrap returns 1, the parser will terminate when
it reaches EOF
int yywrap (void) {return 1;}
/* Regular Definitions */
delim [ \t\n]
ws {delim}+
letter [A-Za-z]
digit [0-9]
id {letter}({letter}|{digit})*
number {digit}+(E[+-]?{digit}+)?
real {digit}+(\.{digit}+)?(E[+-]?{digit}+)?
{ws} {/* no action and no return */}
if {return(IF);}
do {return(DO);}
while {return(WHILE);}
break {return(BREAK);}
then {return(THEN);}
else {return(ELSE);}
true {yylval = &true_var; return(TRUE);}
false {yylval = &false_var; return(FALSE);}
int {yylval = (void *)&int_var; return(BASIC);}
float {yylval = (void *)&float_var; return(BASIC);}
{id} {yylval = malloc(sizeof(yytext)); strcpy(yylval, yytext); return(ID);}
{number} {int *a = malloc(sizeof(int)); *a = (int) atof(yytext);
yylval = a; return (NUM);}
{real} {double *a = malloc(sizeof(double)); *a = (double) atof(yytext);
yylval = a; return (REAL);}
\< {return(LT);}
> {return(GT);}
\<= {return(LE);}
>= {return(GE);}
== {return(EQ);}
!= {return(NE);}
&& {return(AND);}
\|\| {return(OR);}
\n|. {return yytext[0];}
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