%{
#define YYDEBUG 1
#include "node.h"
#include <stdio.h>
%}
%union {
  node* nd;
  double double_value;
}

%type<nd> primary_expression
%type<double_value> DOUBLE_LITERAL
%type<double_value> expression term

%token DOUBLE_LITERAL
%token ADD SUB MUL DIV CR
%token COND_BEGIN COND_END
%token IF ELSE ENDIF

%%
line_list
  : line
  | line_list line
  ;
line
  : expression CR
  {
    printf(">>%lf\n", $1);
  }
expression
  : term
  | expression ADD term
  {
    $$ = $1 + $3;
  }
  | expression SUB term
  {
    $$ = $1 - $3;
  }
  | IF COND_BEGIN expression COND_END expression ELSE expression ENDIF
  {
    $$ = ($3) ? ($5) : ($7);
  }
term
  : primary_expression
  {
    $$ = ((node_float*)$1)->value;
  }
  | term MUL primary_expression
  {
    $$ = $1 * ((node_float*)$3)->value;
  }
  | term DIV primary_expression
  {
    $$ = $1 / ((node_float*)$3)->value;
  }
  ;
primary_expression
  : DOUBLE_LITERAL
  {
    $$ = node_float_new($1);
  }
  ;
%%
int
yyerror(char const *str)
{
  extern char *yytext;
  fprintf(stderr, "parser error near %s\n", yytext);
  return 0;
}

int main(void)
{
  extern int yyparse(void);
  extern FILE *yyin;

  yyin = stdin;
  if(yyparse()) {
    fprintf(stderr, "Error! Error! Error!\n");
    exit(1);
  }
}