convertible_map

template<typename J, typename T, typename D>
concept convertible_map = std::ranges::range<T> && requires {
    requires std::is_constructible_v<typename T::mapped_type, D>;
    requires std::is_convertible_v<typename J::Str, typename T::key_type>;
    requires convertible<J, typename T::mapped_type>;
    requires std::is_default_constructible_v<T>;
    requires std::is_default_constructible_v<typename T::mapped_type>;
    requires std::is_copy_constructible_v<typename T::mapped_type>;
} && requires (T t, typename J::Str s, typename T::mapped_type m) {
    t.emplace(static_cast<typename T::key_type>(s), std::move(m));
};

Located in the mysvac::json namespace, this concept indicates that a JSON container type J can attempt to convert its internal data to key-value pair type T using to()/move() member functions.

Satisfying this concept only means T can be used as a template parameter for to()/move(), while actual conversion success depends on the JSON container's internal data.

The template parameter D represents the default value type for key-value pair type T, which need not be mapped_type but must be convertible to mapped_type. This is used to provide default values for subobjects in conversion functions.

Version

Since v3.0.0 .