kfr

commit ee827301599a0c4a6e67c5bf0ff4926aedd930da
parent 02fa0219dd0cec8503cad03e71e144b466cc7c3f
Author: d.levin256@gmail.com <d.levin256@gmail.com>
Date:   Mon,  2 Dec 2019 18:30:44 +0000

is_invocable

Diffstat:
M
include/kfr/cometa.hpp
 | 
3
+++
M
include/kfr/cometa/function.hpp
 | 
10
+++++-----

2 files changed, 8 insertions(+), 5 deletions(-)
diff --git a/include/kfr/cometa.hpp b/include/kfr/cometa.hpp
@@ -186,6 +186,9 @@ constexpr inline bool is_convertible = std::is_convertible<Tfrom, Tto>::value;
 template <typename T, typename... Args>
 constexpr inline bool is_constructible = std::is_constructible<T, Args...>::value;
 
+template <typename T, typename... Args>
+constexpr inline bool is_invocable = std::is_invocable<T, Args...>::value;
+
 template <typename T>
 constexpr inline bool is_template_arg = std::is_integral<T>::value || std::is_enum<T>::value;
 
diff --git a/include/kfr/cometa/function.hpp b/include/kfr/cometa/function.hpp
@@ -5,10 +5,10 @@
 
 #include "../cometa.hpp"
 #include "memory.hpp"
-#include <cstdlib>
 #include <cstddef>
-#include <type_traits>
+#include <cstdlib>
 #include <memory>
+#include <type_traits>
 #if CMT_HAS_EXCEPTIONS
 #include <functional>
 #endif
@@ -91,9 +91,9 @@ struct function<R(Args...)>
 
     function(nullptr_t) noexcept {}
 
-    template <typename Fn, typename = std::enable_if_t<std::is_invocable_r_v<R, Fn, Args...> &&
-                                                       !std::is_same_v<std::decay_t<Fn>, function>>>
-    function(Fn fn) : impl(new details::function_impl<std::decay_t<Fn>, R, Args...>(std::move(fn)))
+    template <typename Fn,
+              typename = enable_if<is_invocable<R, Fn, Args...> && !is_same<decay<Fn>, function>>>
+    function(Fn fn) : impl(new details::function_impl<decay<Fn>, R, Args...>(std::move(fn)))
     {
     }