%{
#include <stdio.h>
#include <stdlib.h>
#include "lse_syntabstr.tic.h"

  extern void yyerror(char const *);  
  extern int yylineno;
  extern FILE * yyin; 
%}


%union {
  char* str;
  int num;
  union e_expr *e;
  union b_expr *b;
}

%left PLUS
%token LPAR RPAR
%token IF  ELSE
%token THEN
%token LET EQ IN
%token <str> ID 
%token <num> CONST

%type <e> e_expression
%type <b> b_expression

%start S


%%
S: b_expression;

b_expression: e_expression {$$=makeExpr($1);}
| LPAR b_expression RPAR {$$=$2;}
| LET ID EQ e_expression IN b_expression 
   {$$=makeLet($2,$4,$6);} 
| IF e_expression THEN b_expression ELSE b_expression
   {$$=makeIte($2,$4,$6);} 
;

e_expression: ID {$$=makeId($1);} 
| CONST {$$=makeConst($1);}
| e_expression PLUS  e_expression 
    {$$=makePlus($1,$3);}
| LPAR e_expression RPAR {$$=$2;}
;
%%

void yyerror(char const *str)
{
  fprintf(stderr,"Ligne %d : %s\n", yylineno, str); 
  exit(EXIT_FAILURE);
}


int 
main(int argc, char* argv[])
{
  if ( argc > 1 ) {
    if((yyin = fopen( argv[1], "r" ))==NULL)
      exit(EXIT_FAILURE);
    
    yyparse();
    fclose(yyin);
  }
  else exit(EXIT_FAILURE);

  exit(EXIT_SUCCESS);
}