Concept definition

template< typename CHARACTER_RANGE >
concept prototype_character_range =
(::std::is_base_of_v < ::character_range< const typename CHARACTER_RANGE::CHARACTER* >, CHARACTER_RANGE >
&& prototype_character < typename CHARACTER_RANGE::CHARACTER > )||
(::is_same < ::character_range< const typename CHARACTER_RANGE::ITEM* >, CHARACTER_RANGE > &&
prototype_character < typename CHARACTER_RANGE::ITEM >)