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

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

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

    namespace elna::source
    {
    class lexer;
    }
}

%code provides {
    namespace elna::source
    {

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

        lexer(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::source::lexer& lexer}
%parse-param {elna::source::driver& driver}
%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::boolean_literal>> boolean_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::declaration>> variable_declaration;
%type <std::vector<std::unique_ptr<elna::source::declaration>>> variable_declarations variable_declaration_part
    formal_parameter_list;
%type <std::unique_ptr<elna::source::type_expression>> type_expression;
%type <std::unique_ptr<elna::source::expression>> expression pointer summand factor address;
%type <std::vector<std::unique_ptr<elna::source::expression>>> expressions actual_parameter_list;
%type <std::unique_ptr<elna::source::variable_expression>> variable_expression;
%type <std::unique_ptr<elna::source::compound_statement>> compound_statement;
%type <std::unique_ptr<elna::source::assign_statement>> assign_statement;
%type <std::unique_ptr<elna::source::call_statement>> call_statement;
%type <std::unique_ptr<elna::source::while_statement>> while_statement;
%type <std::unique_ptr<elna::source::if_statement>> if_statement;
%type <std::unique_ptr<elna::source::statement>> statement;
%type <std::vector<std::unique_ptr<elna::source::statement>>> statements optional_statements;
%type <std::unique_ptr<elna::source::procedure_definition>> procedure_definition;
%type <std::vector<std::unique_ptr<elna::source::procedure_definition>>> procedure_definitions;
%type <std::unique_ptr<elna::source::block>> block;
%%
program: constant_definition_part variable_declaration_part procedure_definitions statement DOT
        {
            std::vector<std::unique_ptr<elna::source::definition>> definitions($1.size() + $3.size());
            std::vector<std::unique_ptr<elna::source::definition>>::iterator definition = definitions.begin();

            for (auto& constant : $1)
            {
                *definition++ = std::move(constant);
            }
            for (auto& constant : $3)
            {
                *definition++ = std::move(constant);
            }
            driver.tree = std::make_unique<elna::source::program>(elna::source::position{},
                 std::move(definitions), std::move($2),
                 std::move($4));
        }
block: constant_definition_part variable_declaration_part statement
        {
            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);
            }
            $$ = std::make_unique<elna::source::block>(elna::source::position{},
                 std::move(definitions), std::move($2), std::move($3));
        };
procedure_definition:
    PROCEDURE IDENTIFIER formal_parameter_list SEMICOLON block SEMICOLON
        {
            $$ = std::make_unique<elna::source::procedure_definition>(elna::source::position{},
                 std::move($2), std::move($5));
            std::swap($$->parameters(), $3);
        };
procedure_definitions:
    procedure_definition procedure_definitions
        {
            std::swap($$, $2);
            $$.emplace($$.cbegin(), std::move($1));
        }
    | procedure_definition { $$.emplace_back(std::move($1)); }
integer_literal: NUMBER
        {
            $$ = std::make_unique<elna::source::integer_literal>(elna::source::make_position(@1), $1); 
        };
boolean_literal: BOOLEAN
        {
            $$ = std::make_unique<elna::source::boolean_literal>(elna::source::make_position(@1), $1); 
        };
compound_statement: BEGIN_BLOCK optional_statements END_BLOCK
        {
            $$ = std::make_unique<elna::source::compound_statement>(elna::source::make_position(@1));
            std::swap($$->statements(), $2);
        }
assign_statement: IDENTIFIER ASSIGNMENT expression
        {
            $$ = std::make_unique<elna::source::assign_statement>(elna::source::make_position(@1), $1, std::move($3));
        }
call_statement: IDENTIFIER actual_parameter_list
        {
            $$ = std::make_unique<elna::source::call_statement>(elna::source::make_position(@1), $1);
            std::swap($$->arguments(), $2);
        }
while_statement: WHILE expression DO statement
        {
            $$ = std::make_unique<elna::source::while_statement>(elna::source::make_position(@1),
                std::move($2), std::move($4));
        }
if_statement:
    IF expression THEN statement
        {
            $$ = std::make_unique<elna::source::if_statement>(elna::source::make_position(@1),
                std::move($2), std::move($4));
        }
pointer:
    integer_literal { $$ = std::move($1); }
    | boolean_literal { $$ = std::move($1); }
    | variable_expression { $$ = std::move($1); }
    | LEFT_PAREN expression RIGHT_PAREN { $$ = std::move($2); }
summand:
    factor { $$ = std::move($1); }
    | factor MULTIPLICATION factor
        {
            $$ = std::make_unique<elna::source::binary_expression>(elna::source::make_position(@1),
                std::move($1), std::move($3), '*');
        }
    | factor DIVISION factor
        {
            $$ = std::make_unique<elna::source::binary_expression>(elna::source::make_position(@1),
                std::move($1), std::move($3), '/');
        }
address:
    pointer HAT
        {
            $$ = std::make_unique<elna::source::unary_expression>(elna::source::make_position(@1),
                std::move($1), '^');
        }
    | pointer { $$ = std::move($1); }
factor:
    AT address
        {
            $$ = std::make_unique<elna::source::unary_expression>(elna::source::make_position(@1),
                std::move($2), '@');
        }
    | address { $$ = std::move($1); }
expression:
    summand EQUALS summand
        {
            $$ = std::make_unique<elna::source::binary_expression>(elna::source::make_position(@1),
                std::move($1), std::move($3), '=');
        }
    | summand NOT_EQUAL summand
        {
            $$ = std::make_unique<elna::source::binary_expression>(elna::source::make_position(@1),
                std::move($1), std::move($3), 'n');
        }
    | summand LESS_THAN summand
        {
            $$ = std::make_unique<elna::source::binary_expression>(elna::source::make_position(@1),
                std::move($1), std::move($3), '<');
        }
    | summand GREATER_THAN summand
        {
            $$ = std::make_unique<elna::source::binary_expression>(elna::source::make_position(@1),
                std::move($1), std::move($3), '>');
        }
    | summand LESS_EQUAL summand
        {
            $$ = std::make_unique<elna::source::binary_expression>(elna::source::make_position(@1),
                std::move($1), std::move($3), '<');
        }
    | summand GREATER_EQUAL summand
        {
            $$ = std::make_unique<elna::source::binary_expression>(elna::source::make_position(@1),
                std::move($1), std::move($3), '>');
        }
    | summand { $$ = std::move($1); }
expressions:
    expression COMMA expressions
        {
            std::swap($$, $3);
            $$.emplace($$.cbegin(), std::move($1));
        }
    | expression { $$.emplace_back(std::move($1)); }
variable_expression: IDENTIFIER
        { $$ = std::make_unique<elna::source::variable_expression>(elna::source::make_position(@1), $1); }
statement:
    compound_statement { $$ = std::move($1); }
    | assign_statement { $$ = std::move($1); }
    | call_statement { $$ = std::move($1); }
    | while_statement { $$ = std::move($1); }
    | if_statement { $$ = std::move($1); }
statements:
    statement SEMICOLON statements
        {
            std::swap($$, $3);
            $$.emplace($$.cbegin(), std::move($1));
        }
    | statement { $$.emplace_back(std::move($1)); }
optional_statements:
    statements { std::swap($$, $1); }
    | /* no statements */ {}
type_expression:
    HAT IDENTIFIER
        {
            $$ = std::make_unique<elna::source::type_expression>(elna::source::make_position(@1), $2, true);
        }
    | IDENTIFIER
        {
            $$ = std::make_unique<elna::source::type_expression>(elna::source::make_position(@1), $1, false);
        }
variable_declaration: IDENTIFIER COLON type_expression
        {
            $$ = std::make_unique<elna::source::declaration>(elna::source::make_position(@1),
                $1, std::move($3)); 
        };
variable_declarations:
    variable_declaration COMMA variable_declarations
        {
            std::swap($$, $3);
            $$.emplace($$.cbegin(), std::move($1));
        }
    | variable_declaration { $$.emplace_back(std::move($1)); }
variable_declaration_part:
    /* no variable declarations */ {}
    | VAR variable_declarations SEMICOLON { std::swap($$, $2); }
constant_definition: IDENTIFIER EQUALS integer_literal
        {
            $$ = std::make_unique<elna::source::constant_definition>(elna::source::make_position(@1),
                $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($$, $2); };
formal_parameter_list:
    LEFT_PAREN RIGHT_PAREN {}
    | LEFT_PAREN variable_declarations RIGHT_PAREN { std::swap($$, $2); }
actual_parameter_list:
    LEFT_PAREN RIGHT_PAREN {}
    | LEFT_PAREN expressions RIGHT_PAREN { std::swap($$, $2); }
%%

void yy::parser::error(const location_type& loc, const std::string& message)
{
    driver.error(loc, message);
}