Imported Upstream version 1.66.0upstream/1.66.0

1 files changed, 97 insertions, 0 deletions

diff --git a/boost/callable_traits/function_type.hpp b/boost/callable_traits/function_type.hpp
new file mode 100644
index 0000000000..a3305f7bfd
--- /dev/null
+++ b/boost/callable_traits/function_type.hpp
@@ -0,0 +1,97 @@
+/*
+
+@Copyright Barrett Adair 2015-2017
+Distributed under the Boost Software License, Version 1.0.
+(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+
+*/
+
+#ifndef BOOST_CLBL_TRTS_FUNCTION_TYPE_HPP
+#define BOOST_CLBL_TRTS_FUNCTION_TYPE_HPP
+
+#include <boost/callable_traits/detail/core.hpp>
+
+namespace boost { namespace callable_traits {
+
+//[ function_type_hpp
+/*`[section:ref_function_type function_type]
+[heading Header]
+``#include <boost/callable_traits/function_type.hpp>``
+[heading Definition]
+*/
+
+template<typename T>
+using function_type_t = //see below
+//<-
+    detail::try_but_fail_if_invalid<typename detail::traits<
+            detail::shallow_decay<T>>::function_type,
+        cannot_determine_parameters_for_this_type>;
+
+namespace detail {
+
+    template<typename T, typename = std::false_type>
+    struct function_type_impl {};
+
+    template<typename T>
+    struct function_type_impl <T, typename std::is_same<
+        function_type_t<T>, detail::dummy>::type>
+    {
+        using type = function_type_t<T>;
+    };
+}
+
+//->
+
+template<typename T>
+struct function_type : detail::function_type_impl<T> {};
+
+//<-
+}} // namespace boost::callable_traits
+//->
+
+/*`
+[heading Constraints]
+* `T` must be one of the following:
+  * function
+  * function pointer
+  * function reference
+  * member function pointer
+  * member data pointer
+  * user-defined type with a non-overloaded `operator()`
+  * type of a non-generic lambda
+
+[heading Behavior]
+* When the constraints are violated, a substitution failure occurs.
+* When `T` is a function, the aliased type is identical to `T`, except that the aliased function type will not have member qualifiers or the `transaction_safe` specifier.
+* When `T` is a function pointer, the aliased type is equivalent to `std::remove_pointer_t<T>`.
+* When `T` is a function reference, the aliased type is equivalent to `std::remove_reference_t<T>`.
+* When `T` is a function object, the aliased type is a function type with the same return type and parameter list as `T`'s `operator()`.
+* When `T` is a member function pointer, the aliased type is a function type with the same return type as `T`, and the first parameter is a reference to the parent class of `T`, qualified according to the member qualifiers on `T`. The subsequent parameters, if any, are the parameter types of `T`.
+* When `T` is a member data pointer, the aliased type is a function type returning the underlying member type of `T`, taking a single parameter, which is a `const` reference to the parent type of `T`.
+* In all cases, the aliased function type will not have member qualifiers, and will not have the `transaction_safe` specifier.
+
+[heading Input/Output Examples]
+[table
+    [[`T`]                              [`function_type_t<T>`]]
+    [[`void(int)`]                      [`void(int)`]]
+    [[`void(int) const`]                [`void(int)`]]
+    [[`void(int) transaction_safe`]     [`void(int)`]]
+    [[`void(*const &)(int)`]            [`void(int)`]]
+    [[`void(&)(int)`]                   [`void(int)`]]
+    [[`void(* volatile)()`]             [`void()`]]
+    [[`int(foo::*)(int)`]               [`int(foo&, int)`]]
+    [[`int(foo::*)(int) const`]         [`int(const foo&, int)`]]
+    [[`void(foo::*)() volatile &&`]     [`void(volatile foo&&)`]]
+    [[`int foo::*`]                     [`int(const foo&)`]]
+    [[`const int foo::*`]               [`int(const foo&)`]]
+    [[`int`]                            [(substitution failure)]]
+]
+
+[heading Example Program]
+[import ../example/function_type.cpp]
+[function_type]
+[endsect]
+*/
+//]
+
+#endif