renaming function qualifier manipulations

example/add_function_rvalue.cpp

@@ -0,0 +1,55 @@
+/*<-
+Copyright Barrett Adair 2016
+Distributed under the Boost Software License, Version 1.0.
+(See accompanying file LICENSE.md or copy at http ://boost.org/LICENSE_1_0.txt)
+->*/
+
+//[ add_function_rvalue
+#include <type_traits>
+#include <callable_traits/add_function_rvalue.hpp>
+
+namespace ct = callable_traits;
+
+struct foo {};
+
+int main() {
+
+    {
+        using pmf = void(foo::*)();
+        using expect = void(foo::*)() &&;
+        using test = ct::add_function_rvalue<pmf>;
+        static_assert(std::is_same<test, expect>::value, "");
+    } {
+        // add_function_rvalue doesn't change anything when
+        // the function type already has an rvalue qualifier.
+        using pmf = void(foo::*)() &&;
+        using expect = void(foo::*)() &&;
+        using test = ct::add_function_rvalue<pmf>;
+        static_assert(std::is_same<test, expect>::value, "");
+    } {
+        // add_function_rvalue models C++11 reference collapsing
+        // rules, so that adding an rvalue qualifier to an
+        // lvalue-qualified type will not change anything.
+        using pmf = void(foo::*)() const &;
+        using expect = void(foo::*)() const &;
+        using test = ct::add_function_rvalue<pmf>;
+        static_assert(std::is_same<test, expect>::value, "");
+    } {
+        // add_function_rvalue can also be used with "abominable"
+        // function types.
+        using f = void() const;
+        using expect = void() const &&;
+        using test = ct::add_function_rvalue<f>;
+        static_assert(std::is_same<test, expect>::value, "");
+    } {
+        // add_function_rvalue has no affect on function pointers,
+        // function references, function objects, or member data pointers.
+        auto lambda = []{};
+        using lambda_t = decltype(lambda);
+        using expect = lambda_t;
+        using test = ct::add_function_rvalue<lambda_t>;
+        static_assert(std::is_same<test, expect>::value, "");
+    }
+}
+//]
+