From 922907890f389d46f2c54f48d7685e0918d660ea Mon Sep 17 00:00:00 2001
From: Mateusz Pusz <mateusz.pusz@gmail.com>
Date: Thu, 26 Sep 2024 13:04:52 +0200
Subject: [PATCH] feat: `type_list_unique` added

---
 src/core/include/mp-units/bits/type_list.h | 22 ++++++++++++++++++++++
 test/static/type_list_test.cpp             | 12 ++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/src/core/include/mp-units/bits/type_list.h b/src/core/include/mp-units/bits/type_list.h
index 636c1df1..f0e6817f 100644
--- a/src/core/include/mp-units/bits/type_list.h
+++ b/src/core/include/mp-units/bits/type_list.h
@@ -235,6 +235,28 @@ struct type_list_sort_impl<List<Types...>, Pred> {
 template<TypeList List, template<typename, typename> typename Pred>
 using type_list_sort = type_list_sort_impl<List, Pred>::type;
 
+// sort
+template<typename List>
+struct type_list_unique_impl;
+
+template<template<typename...> typename List>
+struct type_list_unique_impl<List<>> {
+  using type = List<>;
+};
+
+template<template<typename...> typename List, typename T, typename... Rest>
+struct type_list_unique_impl<List<T, Rest...>> {
+  using type = type_list_push_front<typename type_list_unique_impl<List<Rest...>>::type, T>;
+};
+
+template<template<typename...> typename List, typename T, typename... Rest>
+struct type_list_unique_impl<List<T, T, Rest...>> {
+  using type = type_list_unique_impl<List<T, Rest...>>::type;
+};
+
+template<TypeList List>
+using type_list_unique = type_list_unique_impl<List>::type;
+
 }  // namespace mp_units::detail
 
 MP_UNITS_DIAGNOSTIC_POP
diff --git a/test/static/type_list_test.cpp b/test/static/type_list_test.cpp
index 35af8b60..5db9afbb 100644
--- a/test/static/type_list_test.cpp
+++ b/test/static/type_list_test.cpp
@@ -189,4 +189,16 @@ static_assert(is_same_v<type_list_sort<type_list<v2, v1>, constant_less>, type_l
 static_assert(is_same_v<type_list_sort<type_list<v2, v1, v3>, constant_less>, type_list<v1, v2, v3>>);
 static_assert(is_same_v<type_list_sort<type_list<v4, v3, v2, v1>, constant_less>, type_list<v1, v2, v3, v4>>);
 
+// type_list_unique
+
+static_assert(is_same_v<type_list_unique<type_list<v1>>, type_list<v1>>);
+static_assert(is_same_v<type_list_unique<type_list<v1, v1>>, type_list<v1>>);
+static_assert(is_same_v<type_list_unique<type_list<v1, v1, v1>>, type_list<v1>>);
+static_assert(is_same_v<type_list_unique<type_list<v1, v2>>, type_list<v1, v2>>);
+static_assert(is_same_v<type_list_unique<type_list<v1, v1, v2>>, type_list<v1, v2>>);
+static_assert(is_same_v<type_list_unique<type_list<v1, v2, v2>>, type_list<v1, v2>>);
+static_assert(is_same_v<type_list_unique<type_list<v1, v2, v3>>, type_list<v1, v2, v3>>);
+static_assert(is_same_v<type_list_unique<type_list<v1, v2, v2, v3>>, type_list<v1, v2, v3>>);
+static_assert(is_same_v<type_list_unique<type_list<v1, v1, v2, v3, v3>>, type_list<v1, v2, v3>>);
+
 }  // namespace