%{
#include <stdio.h>

#include "exprtree.h"

extern exprtree *theExprtree;
%}

%union {
    ident ident;
    exprtree *exprtree;
}

%token T_IDENT T_NUMBER

%left '+' '-'
%left '*' '/' '%'
%left NEG

%%

start :   expr               { theExprtree = $<exprtree>1; }
        ;

expr :   T_NUMBER            { $<exprtree>$ = $<exprtree>1; }
       | T_IDENT             { $<exprtree>$ = make_var($<ident>1); }
       | expr '+' expr       { $<exprtree>$ = make_operator(EXPR_ADD,
                                                            $<exprtree>1, $<exprtree>3); }
       | expr '-' expr       { $<exprtree>$ = make_operator(EXPR_SUB,
                                                            $<exprtree>1, $<exprtree>3); }
       | expr '*' expr       { $<exprtree>$ = make_operator(EXPR_MUL,
                                                            $<exprtree>1, $<exprtree>3); }
       | expr '/' expr       { $<exprtree>$ = make_operator(EXPR_DIV,
                                                            $<exprtree>1, $<exprtree>3); }
       | expr '%' expr       { $<exprtree>$ = make_operator(EXPR_MOD,
                                                            $<exprtree>1, $<exprtree>3); }
       | '-' expr %prec NEG  { $<exprtree>$ = make_operator(EXPR_NEG, $<exprtree>2, 0); }
       | '(' expr ')'        { $<exprtree>$ = $<exprtree>2; };
       | T_IDENT '(' arglist ')' { $<exprtree>$ = make_function($<ident>1, $<exprtree>3); }
       ;

arglist :                    { $<exprtree>$ = 0; }
          | args             { $<exprtree>$ = $<exprtree>1; }
          ;

args :   expr                { $<exprtree>$ = $<exprtree>1; }
       | args ',' expr       { $<exprtree>$ = arglist_append($<exprtree>1, $<exprtree>3); }
       ;

%%

int
yyerror (char *s)
{
    fprintf(stderr, "%s\n", s);

    return 0;
}