From bb05e3434ea488c805780b46f72e5b9357aa29e8 Mon Sep 17 00:00:00 2001
From: Mateusz Pusz <mateusz.pusz@gmail.com>
Date: Wed, 8 Feb 2023 22:03:41 -0800
Subject: [PATCH] feat: type traits for template template auto parameters added

---
 .../mp_units/bits/external/type_traits.h      | 30 ++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/src/core/include/mp_units/bits/external/type_traits.h b/src/core/include/mp_units/bits/external/type_traits.h
index bc227acc..5f3779ee 100644
--- a/src/core/include/mp_units/bits/external/type_traits.h
+++ b/src/core/include/mp_units/bits/external/type_traits.h
@@ -65,6 +65,12 @@ inline constexpr bool is_specialization_of = false;
 template<typename... Params, template<typename...> typename Type>
 inline constexpr bool is_specialization_of<Type<Params...>, Type> = true;
 
+template<typename T, template<auto...> typename Type>
+inline constexpr bool is_specialization_of_v = false;
+
+template<auto... Params, template<auto...> typename Type>
+inline constexpr bool is_specialization_of_v<Type<Params...>, Type> = true;
+
 // is_derived_from_specialization_of
 namespace detail {
 
@@ -92,6 +98,12 @@ consteval bool contains()
   return (false || ... || is_specialization_of<Ts, T>);
 }
 
+template<template<auto...> typename T, typename... Ts>
+consteval bool contains()
+{
+  return (false || ... || is_specialization_of_v<Ts, T>);
+}
+
 template<typename T, std::same_as<T> auto V>
 consteval auto get()
 {
@@ -117,7 +129,23 @@ consteval auto get()
 template<template<typename...> typename T, typename T1, typename T2, typename... Ts>
 consteval auto get()
 {
-  if constexpr (is_specialization_of<T1, T2, T>)
+  if constexpr (is_specialization_of<T1, T>)
+    return T1{};
+  else
+    return get<T, T2, Ts...>();
+}
+
+template<template<auto...> typename T, typename T1>
+  requires is_specialization_of_v<T1, T>
+consteval auto get()
+{
+  return T1{};
+}
+
+template<template<auto...> typename T, typename T1, typename T2, typename... Ts>
+consteval auto get()
+{
+  if constexpr (is_specialization_of_v<T1, T>)
     return T1{};
   else
     return get<T, T2, Ts...>();