token.hpp

/*
 * CoNLL-U - https://github.com/tugrulgungor/CoNLL-U
 *
 * Copyright (c) 2026. All rights reserved.
 * Tuğrul Güngör - https://conll-u.tugrulgungor.me
 *
 * Distributed under the MIT License.
 * https://opensource.org/license/mit/
 */

 
#ifndef TG_CONLLU_TOKEN_HPP
#define TG_CONLLU_TOKEN_HPP 1
 
#include "conllu/error.hpp"
 
#include <charconv>
#include <expected>
#include <format>
#include <optional>
#include <string>
#include <unordered_map>
#include <vector>
 
namespace tg::conllu {
    class Sentence;
    class Word;

    using TokenId = std::uint64_t;

    class Token final {
        TokenId id_{};
        std::optional<TokenId> head_{std::nullopt};
 
        std::vector<std::optional<std::string>> fields_{};
 
        std::vector<std::unique_ptr<Token>> empty_nodes_{};
 
        Token *parent_{nullptr};
        Sentence *sentence_{nullptr};
 
        [[nodiscard]] constexpr std::optional<std::error_code> set_known_field_(
        std::size_t position, std::string_view name, const std::optional<std::string_view> &value) noexcept;
        [[nodiscard]] constexpr std::error_code set_field_value_(std::size_t position,
                                                                 const std::optional<std::string_view> &value) noexcept;
        [[nodiscard]] constexpr std::error_code set_field_value_(std::size_t position, std::string_view name,
                                                                 const std::optional<std::string_view> &value) noexcept;
 
        [[nodiscard]] constexpr std::error_code set_head_(const std::optional<std::string_view> &value) noexcept;
 
        explicit(true) constexpr Token(Sentence *sentence, Token *parent) noexcept;
 
        friend class Parser;
        friend class Sentence;
        friend class Treebank;
        friend class Word;
        friend class Writer;
 
    public:
        constexpr Token() noexcept = delete;
        [[nodiscard]] constexpr Sentence *sentence() const noexcept;
        [[nodiscard]] constexpr Token *get_parent() const noexcept;
        [[nodiscard]] constexpr TokenId get_id() const noexcept;
        [[nodiscard]] constexpr std::optional<Token *> get_head() const noexcept;
        constexpr std::error_code set_head(TokenId id) noexcept;
        [[nodiscard]] constexpr bool is_empty_node() const noexcept;
        [[nodiscard]] constexpr std::optional<Word *> get_word() const noexcept;
        [[nodiscard]] constexpr bool is_in_word() const noexcept;
        [[nodiscard]] constexpr auto fields() const noexcept;
        [[nodiscard]] constexpr std::size_t num_fields() const noexcept;
        [[nodiscard]] constexpr std::optional<std::string_view> get_field_value(std::size_t position) const noexcept;
        [[nodiscard]] constexpr std::optional<std::string_view> get_field_value(std::string_view name) const noexcept;
        [[nodiscard]] constexpr std::error_code set_field_value(std::size_t position, std::string_view value) noexcept;
        [[nodiscard]] constexpr std::error_code set_field_value(std::string_view name, std::string_view value) noexcept;
        [[nodiscard]] constexpr std::error_code unset_field_value(std::size_t position) noexcept;
        [[nodiscard]] constexpr std::error_code unset_field_value(std::string_view name) noexcept;
        [[nodiscard]] constexpr auto empty_nodes() const noexcept;
        [[nodiscard]] constexpr std::size_t empty_node_count() const noexcept;
        [[nodiscard]] constexpr std::expected<Token *, std::error_code> add_empty_node() noexcept;
        constexpr std::error_code remove_empty_node(TokenId id) noexcept;
        constexpr std::error_code remove_empty_node(Token *node) noexcept;
        constexpr void remove_all_empty_nodes() noexcept;
        [[nodiscard]] constexpr std::error_code validate() const noexcept;
        constexpr ~Token() noexcept = default;
    };
} // namespace tg::conllu
 
#endif // TG_CONLLU_TOKEN_HPP