pol.y

%{
#include <stdio.h>
%}

%token COLON
%token COLON_EQUAL
%token NUMBER
%token PLUS
%token TIMES
%token VARIABLE

%% 
assignment	: VARIABLE COLON_EQUAL iterm_list
		| VARIABLE COLON 
		    {yyerror("':=' expected");}
		| VARIABLE NUMBER
		    {yyerror("':=' expected");}
		| VARIABLE VARIABLE
		    {yyerror("invalid id");}
		;
iterm_list	: iterm
                | iterm_list iterm_list PLUS
                | iterm_list iterm_list TIMES
                ;
iterm		: VARIABLE
                | NUMBER  
		;

%%
#include "lex.yy.c" 

yyerror(s)
	char *s;
{
  if (!strcmp(s,"parse error"))
     printf("Ligne %d: Erro sinta'tico perto de \"%s\"\n", 
	    yylineno,yytext);
  else
     printf("Ligne %d: %s\n", yylineno, s);
}


main  ()
{
  printf("Digite uma atribuicao: ");
  yyparse();
}