scan.l

   1 %option noinput
   2 %option nounput
   3 %{
   4
   5 #include <stdio.h>
   6 #include "ast.h"
   7 #define YYSTYPE struct ast *
   8 #include "y.tab.h"
   9 extern YYSTYPE yylval;
  10
  11 %}
  12
  13 %%
  14
  15 [0-9]+      { yylval = ast_int(atoi(yytext)); return INTEGER; }
  16 \+          return PLUS;
  17 -           return MINUS;
  18 \*          return TIMES;
  19 \/          return DIVIDE;
  20 \(          return BOPEN;
  21 \)          return BCLOSE;
  22 \;          return SEMICOLON;
  23 [ \n\t]  ;
  24
  25 %%