text: #include <stdio.h>
  #include <stdlib.h>
  #include <ctype.h>
  #include <string.h>
  #include "y.tab.h"
  
  extern int tokenval;
  extern int lineno;
  struct entry
  {
    char *lexptr;
    int token;
  };
  extern struct entry symtable[];
  int insert (char s[], int tok);
  void error (char *m) ;
  int lookup (char s[]) ;
  void init () ;
  void parse () ;
  int lexan () ;
  void expr () ;
  void term () ;
  void factor () ;
  void match (int t) ;
  void emit (int t, int tval) ;
  
  