/**
 * lisp-compiler: Compiles LISP using LLVM.
 * Copyright (C) 2022  Clyne Sullivan
 *
 * This program is free software: you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * @file parser.hpp
 * @brief Source code parser to produce AST.
 */

#ifndef PARSER_HPP
#define PARSER_HPP

#include "ast.hpp"
#include "state.hpp"

#include <deque>
#include <optional>
#include <string>
#include <variant>

class Parser {
public:
    enum Error {
        None,
        ExpectedProcedure,
        ExpectedIdentifier,
        ExpectedProcedureCallClose,
        ExpectedArgumentList,
        UnknownIdentifier,
        InvalidOperator,
        InvalidOperand,
    };

    void addString(const std::string& str);

    void consumeWhitespace();
    std::optional<std::string> consumeIdentifier();
    std::optional<std::variant<int, double>> consumeLiteralNumber();

    AST::Node *parse(CompilerState&);

private:
    std::deque<char> text;
    Error lastError = None;

    AST::Node *parseExpression();
    AST::Node *parseProcedureCall();
    AST::Node *parseConditional();
    AST::Node *parseDefinition();
    AST::Node *parseAssignment();
    AST::Node *parseLambdaExpression();
};

#endif // PARSER_HPP