%{
extern int yylex();
#include <stdio.h>
int yyerror (char const *message) { 
  fprintf(stderr,"<%s>\n", message);
  return 0;
}
#include <stdlib.h>
#include "set.h"
Set_t Var[100]; /* tableau des variables */
%}

%error-verbose

%union {
  int index;    /* valeur = indice de variable S_i */
  Elem_t elem;  /* valeur = elemt d'ensemble */
  Set_t set;    /* Ensemble (bit-vector) */
}

%token <index> VAR  
%token <elem> ELEM  
%token '(' ')' '{' '}' ',' '\n' '='
%token UNION INTER COMP DIFF

%type <set> Expr E_list U_list I_list

%%
Ligne   :
	  | Ligne  Expr         '\n' {printf("  == "); Println_set($2);}
	  | Ligne  VAR '=' Expr '\n' {Var[$2]=$4; printf("Var[%d] = ",$2); Println_set($4);}
	  | Ligne  error        '\n' {yyerrok; printf(" ERREUR SYNTAXE \n");}
        ;

Expr : '{' '}'                     {$$=Empty_set();}
     | '{' E_list '}'              {$$=$2;}
  //   | UNION '(' Expr ',' Expr ')' {$$=Union_set($3,$5);}
  //   | INTER '(' Expr ',' Expr ')' {$$=Inter_set($3,$5);}
     | UNION '(' U_list ')'        {$$=$3;}
     | INTER '(' I_list ')'        {$$=$3;}
     | DIFF  '(' Expr ',' Expr ')' {$$=Diff_set($3,$5);}
     | COMP  '(' Expr ')'          {$$=Comp_set($3);}
     | VAR                         {$$=Var[$1];}

E_list :          ELEM  {$$=Singleton_set($1);}
     | E_list ',' ELEM  {$$=Add_elem_set($3,$1);}

I_list : Expr {$$=$1;}
       | I_list ',' Expr {$$=Inter_set($1,$3);}

U_list : Expr {$$=$1;}
       | U_list ',' Expr {$$=Union_set($1,$3);}

%%
int main(void) { return yyparse(); }