%token NUMBER
%token ID
%token STRING
%token PLUS
%token MINUS
%token MULTIPLY
%token DIVIDE
%token MOD
%token EQUAL
%token LESS_THAN
%token GREATER_THAN
%token QUOTE
%token BANG
%token BAR
%token AMPERSAND
%token POINT
%token COMMA
%token SEMICOLON
%token COLON
%token QUESTION
%token LEFT_PAREN
%token RIGHT_PAREN
%token LEFT_BRACE
%token RIGHT_BRACE
%token LEFT_BRACKET
%token RIGHT_BRACKET
%token COMMENT
%token NEWLINE

%left PLUS MINUS
%left BANG
%left LEFT_PAREN RIGHT_PAREN

%{
#include "ast.h"
#define YYSTYPE struct Node*
%}

%%
Main                    : Expression NEWLINE
                        {
                            PrintTree($1);
                        }

PrimaryExpression       : ID
                        {
                            $$ = MakeIdentifierNode(yytext);
                        }
                        | NUMBER
                        {
                            $$ = MakeNumberNode(yytext);
                        }
                        | STRING
                        {
                            $$ = MakeStringNode(yytext);
                        }
                        | LEFT_PAREN Expression RIGHT_PAREN
                        ;

UnaryExpression         : BANG Expression
                        {
                            $$ = MakeUnaryNode(Negate, $2);
                        }

BinaryExpression        : Expression PLUS Expression
                        {
                            $$ = MakeBinaryNode(Add, $1, $3);
                        }
                        | Expression MINUS Expression
                        {
                            $$ = MakeBinaryNode(Subtract, $1, $3);
                        }

Expression              : PrimaryExpression
                        | UnaryExpression
                        | BinaryExpression
                        ;
%%

#include "lex.yy.c"

/* yacc error handler */
void yyerror(char *s)
{
    fprintf (stderr, "%s\n", s);
}

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