draconisplusplus/include/rfl/Field.hpp

#ifndef RFL_FIELD_HPP_
#define RFL_FIELD_HPP_

#include <algorithm>
#include <string_view>
#include <tuple>
#include <type_traits>
#include <utility>

#include "Literal.hpp"
#include "default.hpp"
#include "internal/Array.hpp"
#include "internal/StringLiteral.hpp"
#include "internal/to_std_array.hpp"
#include "internal/wrap_in_rfl_array_t.hpp"

namespace rfl {

  /// Used to define a field in the NamedTuple.
  template <internal::StringLiteral _name, class T>
  struct Field {
    /// The underlying type.
    using Type = internal::wrap_in_rfl_array_t<T>;

    /// The name of the field.
    using Name = rfl::Literal<_name>;

    Field(const Type& _value) : value_(_value) {}

    Field(Type&& _value) noexcept : value_(std::move(_value)) {}

    Field(Field<_name, T>&& _field) noexcept = default;

    Field(const Field<_name, T>& _field) = default;

    template <class U>
    Field(const Field<_name, U>& _field) : value_(_field.get()) {}

    template <class U>
    Field(Field<_name, U>&& _field) : value_(_field.get()) {}

    template <class U, typename std::enable_if<std::is_convertible_v<U, Type>, bool>::type = true>
    Field(const U& _value) : value_(_value) {}

    template <class U, typename std::enable_if<std::is_convertible_v<U, Type>, bool>::type = true>
    Field(U&& _value) noexcept : value_(std::forward<U>(_value)) {}

    template <class U, typename std::enable_if<std::is_convertible_v<U, Type>, bool>::type = true>
    Field(const Field<_name, U>& _field) : value_(_field.value()) {}

    /// Assigns the underlying object to its default value.
    template <
      class U                                                                 = Type,
      typename std::enable_if<std::is_default_constructible_v<U>, bool>::type = true>
    Field(const Default& _default) : value_(Type()) {}

    ~Field() = default;

    /// The name of the field, for internal use.
    constexpr static const internal::StringLiteral name_ = _name;

    /// Returns the underlying object.
    const Type& get() const { return value_; }

    /// The name of the field.
    constexpr static std::string_view name() { return name_.string_view(); }

    /// Returns the underlying object.
    Type& operator()() { return value_; }

    /// Returns the underlying object.
    const Type& operator()() const { return value_; }

    /// Assigns the underlying object.
    auto& operator=(const Type& _value) {
      value_ = _value;
      return *this;
    }

    /// Assigns the underlying object.
    auto& operator=(Type&& _value) noexcept {
      value_ = std::move(_value);
      return *this;
    }

    /// Assigns the underlying object.
    template <class U, typename std::enable_if<std::is_convertible_v<U, Type>, bool>::type = true>
    auto& operator=(const U& _value) {
      value_ = _value;
      return *this;
    }

    /// Assigns the underlying object to its default value.
    template <
      class U                                                                 = Type,
      typename std::enable_if<std::is_default_constructible_v<U>, bool>::type = true>
    auto& operator=(const Default& _default) {
      value_ = Type();
      return *this;
    }

    /// Assigns the underlying object.
    Field<_name, T>& operator=(const Field<_name, T>& _field) = default;

    /// Assigns the underlying object.
    Field<_name, T>& operator=(Field<_name, T>&& _field) = default;

    /// Assigns the underlying object.
    template <class U>
    auto& operator=(const Field<_name, U>& _field) {
      value_ = _field.get();
      return *this;
    }

    /// Assigns the underlying object.
    template <class U>
    auto& operator=(Field<_name, U>&& _field) {
      value_ = std::forward<T>(_field.value_);
      return *this;
    }

    /// Assigns the underlying object.
    void set(const Type& _value) { value_ = _value; }

    /// Assigns the underlying object.
    void set(Type&& _value) { value_ = std::move(_value); }

    /// Returns the underlying object.
    Type& value() { return value_; }

    /// Returns the underlying object.
    const Type& value() const { return value_; }

    /// The underlying value.
    Type value_;
  };

  template <internal::StringLiteral _name, class T>
  inline auto make_field(T&& _value) {
    using T0 = std::remove_cvref_t<T>;
    if constexpr (std::is_array_v<T0>) {
      return Field<_name, T0>(internal::Array<T0>(std::forward<T>(_value)));
    } else {
      return Field<_name, T0>(std::forward<T>(_value));
    }
  }

} // namespace rfl

#endif // RFL_FIELD_HPP_