%{

#include <iostream>
using namespace std;
extern int yylex();
extern int lineno;
void yyerror(char*s);
#include "stab.h"

Symbol_Table stab;

%}
%union {
  int value;
  char name;
}

%token EQUAL PLUS TIMES CR RPAREN LPAREN
%token <name> ID
%token <value> INT
%type <value> expr term factor
%%
lines	:	lines line
	|	line
	;
line	:	expr CR		{cout << "= " << $1 << endl; }
	|	ID EQUAL expr CR {stab.assign($1,$3); }
	;
expr	:	expr PLUS term	{$$ = $1 + $3;}
	|	term
	;
term	:	term TIMES factor	{$$ = $1 * $3;}
	|	factor
	;
factor	:	LPAREN expr RPAREN  	{$$ = $2;}
	|	INT
	|	ID { $$=stab.lookup($1); }
	;
%%

int main()
{ yyparse(); }

void yyerror(char *s) {
   cout << "Syntax error on line " << lineno << endl;
}