/* file name: calc4.l */

/* lexer for calculator with variable identifiers. */
/* flex specification */

%{
#include "symtab4.h"     /* declaration of `symrec'  */
#include "calc4.tab.h"
%}

DIGIT  [0-9]
LETTER [A-Za-z]

%%

{DIGIT}+("."{DIGIT}+)?  {
         yylval.val = atof(yytext); return NUM; }

[ \t]    /* ignore whitespace */

{LETTER}({LETTER}|{DIGIT})*  {
         symrec *sym;
         sym = getsym(yytext);
         if (sym == 0)
           sym = putsym(yytext);
         yylval.tptr = sym;
         return VAR; }

<<EOF>>  yyterminate();  /* signal end of dialogue */

\n       return yytext[0];
.        return yytext[0];

%%