%{
#include <stdio.h>

#include "ast.c"

extern FILE *yyin;

extern int yylex();
extern void yyerror();

ast_node* yyast = NULL;
%}

%define parse.error verbose

%union {
  char* string;
  int number;
  ast_node* node;
}

%token OPERATOR_PLUS
%token OPERATOR_MINUS
%token ASSIGN

%token FUNCTION
%token IF
%token ELSE
%token RETURN
%token CONST
%token VAR

%token TYPE_INTEGER
%token TYPE_STRING
%token TYPE_VOID

%token PARENTHESIS_LEFT
%token PARENTHESIS_RIGHT
%token BRACE_LEFT
%token BRACE_RIGHT
%token BRACKET_LEFT
%token BRACKET_RIGHT

%token COMMA;
%token COLON;

%token NUMBER;
%token IDENTIFIER
%token COMMENT;

%token END_OF_LINE;

%type <node> program
%type <node> function
%type <node> arguments
%type <node> argument
%type <node> return_type
%type <node> variable_type
%type <node> statements
%type <node> statement
%type <node> expression

%type <node> IDENTIFIER
%type <node> RETURN

%start program

%%
program: { $$ = NULL; }
  | program statement END_OF_LINE { $$ = create_program_node($1, $2); }


// function henshin(): void {}
// function henshin(hen: integer, shin: integer): void {}
function:
  | FUNCTION IDENTIFIER PARENTHESIS_LEFT PARENTHESIS_RIGHT COLON return_type BRACE_LEFT statements BRACE_RIGHT
  | FUNCTION IDENTIFIER PARENTHESIS_LEFT arguments PARENTHESIS_RIGHT COLON return_type BRACE_LEFT statements BRACE_RIGHT { $$ = create_node(); $$->value = $2; }

arguments:
  | argument
  | arguments COMMA argument

argument:
  | IDENTIFIER COLON variable_type


return_type:
  | TYPE_INTEGER
  | TYPE_STRING
  | TYPE_VOID

variable_type:
  | TYPE_INTEGER
  | TYPE_STRING


statements:
  | statement
  | statements END_OF_LINE statement

statement:
  // const henshin: integer = 2
  | CONST IDENTIFIER COLON variable_type ASSIGN expression
  | RETURN expression { $$ = create_node(); $$->left = $1; $$->right = $2; }
  | IDENTIFIER PARENTHESIS_LEFT PARENTHESIS_RIGHT
  | function


expression:
  | NUMBER
  | IDENTIFIER
%%

void main (int argc, char **argv)
{
  //henshin_lex();
  yyin = fopen(argv[1], "r");
  yyparse();

  printf("%s", yyast);
}