refactor: redesign the type system | embrace the new bit_type concept

include/concept.h

@@ -0,0 +1,41 @@
+#pragma once
+#include <cstdint>
+#include <concepts>
+
+namespace dark {
+
+using max_size_t = std::uint32_t;
+using max_ssize_t = std::int32_t;
+
+} // namespace dark
+
+namespace dark::concepts {
+
+template <typename _Tp>
+using func_t = void(*)(_Tp);
+
+template <typename _From, typename _To>
+concept implicit_convertible_to = requires(_From &a, func_t <_To> b) {
+    b(a); // Can implicitly convert
+};
+
+template <typename _From, typename _To>
+concept explicit_convertible_to =
+    !implicit_convertible_to <_From, _To>
+&&   std::constructible_from <_To, _From>;
+
+template <typename _Tp>
+concept has_length = requires { _Tp::_Bit_Len; };
+
+template <typename _Tp>
+concept bit_type =  has_length <_Tp> && explicit_convertible_to <_Tp, max_size_t>;
+
+template <typename _Tp>
+concept int_type = !has_length <_Tp> && implicit_convertible_to <_Tp, max_size_t>;
+
+template <typename _Lhs, typename _Rhs>
+concept bit_match =
+    (bit_type <_Lhs> && bit_type <_Rhs> && _Lhs::_Bit_Len == _Rhs::_Bit_Len)
+||  (int_type <_Lhs> || int_type <_Rhs>);
+
+} // namespace dark::concepts