%require "3.2"
%language "c++"

%code requires {
    #include <cstdint>
    #include <iostream>
    #include "elna/source/parser.hpp"


    #if ! defined(yyFlexLexerOnce)
        #include <FlexLexer.h>
    #endif

    namespace elna::syntax
    {
    class FooLexer;
    }
}

%code provides {
    namespace elna::syntax
    {

    class FooLexer : public yyFlexLexer
    {
    public:
        yy::location location;

        FooLexer(std::istream& arg_yyin)
            : yyFlexLexer(&arg_yyin)
        {
        }

        yy::parser::symbol_type lex();
    };

    }
}

%define api.token.raw
%define api.token.constructor
%define api.value.type variant
%define parse.assert

%parse-param {elna::syntax::FooLexer& lexer}
%parse-param {std::unique_ptr<elna::source::program>& program}
%locations

%header

%code {
    #define yylex lexer.lex
}
%start program;

%token <std::string> IDENTIFIER "identifier"
%token <std::int32_t> NUMBER "number"
%token <bool> BOOLEAN
%token IF THEN WHILE DO
%token CONST VAR PROCEDURE
%token BEGIN_BLOCK END_BLOCK
%token TRUE FALSE
%token LEFT_PAREN RIGHT_PAREN SEMICOLON DOT COMMA
%token GREATER_EQUAL LESS_EQUAL LESS_THAN GREATER_THAN NOT_EQUAL EQUALS
%token PLUS MINUS MULTIPLICATION DIVISION
%token ASSIGNMENT COLON HAT AT

%type <std::unique_ptr<elna::source::integer_literal>> integer_literal;
%type <std::unique_ptr<elna::source::constant_definition>> constant_definition;
%type <std::vector<std::unique_ptr<elna::source::constant_definition>>> constant_definition_part constant_definitions;
%type <std::unique_ptr<elna::source::type_expression>> type_expression;
%%
program: constant_definition_part
        {
            elna::source::position position;
            std::vector<std::unique_ptr<elna::source::declaration>> declarations;
            std::vector<std::unique_ptr<elna::source::definition>> definitions($1.size());
            std::vector<std::unique_ptr<elna::source::definition>>::iterator definition = definitions.begin();

            for (auto& constant : $1)
            {
                *definition++ = std::move(constant);
            }
            program = std::make_unique<elna::source::program>(position,
                 std::move(definitions), std::move(declarations),
                 std::make_unique<elna::source::compound_statement>(position));
        }
integer_literal: NUMBER
        {
            elna::source::position position{
                static_cast<std::size_t>(@1.begin.line),
                static_cast<std::size_t>(@1.begin.column)
            };
            $$ = std::make_unique<elna::source::integer_literal>(position, $1); 
        };
type_expression:
        HAT IDENTIFIER
            {
                elna::source::position position{
                    static_cast<std::size_t>(@1.begin.line),
                    static_cast<std::size_t>(@1.begin.column)
                };
                $$ = std::make_unique<elna::source::type_expression>(position, $2, true);
            }
        | IDENTIFIER
            {
                elna::source::position position{
                    static_cast<std::size_t>(@1.begin.line),
                    static_cast<std::size_t>(@1.begin.column)
                };
                $$ = std::make_unique<elna::source::type_expression>(position, $1, false);
            }
variable_declaration: IDENTIFIER COLON type_expression
variable_declarations:
        variable_declaration COMMA variable_declarations
        | variable_declaration
constant_definition: IDENTIFIER EQUALS integer_literal
        {
            elna::source::position position{
                static_cast<std::size_t>(@1.begin.line),
                static_cast<std::size_t>(@1.begin.column)
            };
            $$ = std::make_unique<elna::source::constant_definition>(position,
                $1, std::move($3)); 
        };
constant_definitions:
    constant_definition COMMA constant_definitions
        {
            std::swap($$, $3);
            $$.emplace($$.cbegin(), std::move($1));
        }
    | constant_definition { $$.emplace_back(std::move($1)); }
constant_definition_part:
    /* no constant definitions */ {}
    | CONST constant_definitions SEMICOLON { std::swap($$, $2); };
%%

void yy::parser::error(const location_type& loc, const std::string &message)
{
    std::cerr << "Error: " << message << std::endl;
}