%{
#include <stdio.h>
extern int yylval;
extern int symcount;
typedef struct {
  char mysymbol[20];
  int value;} SYMBOL_TBL;


SYMBOL_TBL sym_tbl[100];
#include "y.tab.h"
int x;
%}

letter [A-Za-z]
digit  [0-9]

ident  {letter}({letter}|{digit})*
op    "+"|"-"|"*"|"/"|"("|")"|";"
ws    [ \t\n]+
other .

%%
{ws}    ;
"if"    {return IF;}
"print" { return PRINT;}
"then"  { return THEN;}
"else"  { return ELSE;}
"endif" { return ENDIF; }
{ident} {
         yylval = install(yytext,0);
         return ID;
        }
{op}    return yytext[0];

{digit}+ {
         sscanf(yytext,"%d",&x);
         yylval = install(yytext,x);
          return NUM;
         }

"="    return ASSIGN;

.       ;

%%

int install(char *ident, int val)
{
 int i;
 i = 1;
 while ((i <= symcount) && strcmp(ident, sym_tbl[i].mysymbol)) 
 i++;
 if (i <= symcount) return i;
 else 
  {
   symcount++;
   strcpy(sym_tbl[symcount].mysymbol,ident);
   sym_tbl[symcount].value = val;
   return symcount;
  }
}