From 4914be80995ec0e2d620da070f9301e7c29b4582 Mon Sep 17 00:00:00 2001
From: lisyarus <lisyarus@gmail.com>
Date: Thu, 4 Mar 2021 18:37:07 +0300
Subject: [PATCH] Proper sfinae for vector & point constructors instead of
 static_assert

---
 libs/geom/include/psemek/geom/detail/array.hpp | 15 +++++++++++++++
 libs/geom/include/psemek/geom/point.hpp        |  6 ++----
 libs/geom/include/psemek/geom/vector.hpp       |  6 ++----
 3 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/libs/geom/include/psemek/geom/detail/array.hpp b/libs/geom/include/psemek/geom/detail/array.hpp
index 53cf4895..3e451546 100644
--- a/libs/geom/include/psemek/geom/detail/array.hpp
+++ b/libs/geom/include/psemek/geom/detail/array.hpp
@@ -32,4 +32,19 @@ namespace psemek::geom::detail
 		};
 	};
 
+	template <typename T, typename ... Args>
+	struct all_convertible_to;
+
+
+	template <typename T>
+	struct all_convertible_to<T>
+		: std::true_type
+	{};
+
+	template <typename T, typename H, typename ... Args>
+	struct all_convertible_to<T, H, Args...>
+		: std::bool_constant<std::is_convertible_v<H, T>
+			&& all_convertible_to<T, Args...>::value>
+	{};
+
 }
diff --git a/libs/geom/include/psemek/geom/point.hpp b/libs/geom/include/psemek/geom/point.hpp
index 2bce6b0b..253ad190 100644
--- a/libs/geom/include/psemek/geom/point.hpp
+++ b/libs/geom/include/psemek/geom/point.hpp
@@ -24,12 +24,10 @@ namespace psemek::geom
 		point & operator = (point &) = default;
 		point & operator = (point &&) = default;
 
-		template <typename ... Args>
+		template <typename ... Args, typename = std::enable_if_t<(sizeof...(Args) == N) && detail::all_convertible_to<T, Args...>::value>>
 		point(Args && ... args)
 			: coords{ static_cast<T>(std::forward<Args>(args))... }
-		{
-			static_assert(sizeof...(Args) == N);
-		}
+		{}
 
 		std::size_t dimension() const
 		{
diff --git a/libs/geom/include/psemek/geom/vector.hpp b/libs/geom/include/psemek/geom/vector.hpp
index bb20a72b..0e9681f3 100644
--- a/libs/geom/include/psemek/geom/vector.hpp
+++ b/libs/geom/include/psemek/geom/vector.hpp
@@ -29,12 +29,10 @@ namespace psemek::geom
 		vector & operator = (vector &) = default;
 		vector & operator = (vector &&) = default;
 
-		template <typename ... Args>
+		template <typename ... Args, typename = std::enable_if_t<(sizeof...(Args) == N) && detail::all_convertible_to<T, Args...>::value>>
 		vector(Args && ... args)
 			: coords{ static_cast<T>(std::forward<Args>(args))... }
-		{
-			static_assert(sizeof...(Args) == N);
-		}
+		{}
 
 		std::size_t dimension() const
 		{