[libcxx] Implement n4169 - Add invoke function template.

[mclow.lists]

The code LGTM. Working my way through the tests.

[EricWF]

Mark test XFAIL in c++14.

[mclow.lists]

LGTM.

www/cxx1z_status.html

57

This should be 3.7 - the first released version to contain this feature.

[EricWF]

Fixed the cxx1Z status. Committed as r242195.

include/functional

 };
 #endif
 
+
+#if _LIBCPP_STD_VER > 14
+template <class _Fn, class ..._Args>
+result_of_t<_Fn&&(_Args&&...)>
+invoke(_Fn&& __f, _Args&&... __args) {
+    return __invoke(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)...);
+}
+#endif
+
 // struct hash<T*> in <memory>
 
 _LIBCPP_END_NAMESPACE_STD

test/std/utilities/function.objects/func.invoke/invoke.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+
+// <functional>
+
+// template <class F, class ...Args>
+// result_of_t<F&&(Args&&...)> invoke(F&&, Args&&...);
+
+/// C++14 [func.def] 20.9.0
+/// (1) The following definitions apply to this Clause:
+/// (2) A call signature is the name of a return type followed by a parenthesized
+///     comma-separated list of zero or more argument types.
+/// (3) A callable type is a function object type (20.9) or a pointer to member.
+/// (4) A callable object is an object of a callable type.
+/// (5) A call wrapper type is a type that holds a callable object and supports
+///     a call operation that forwards to that object.
+/// (6) A call wrapper is an object of a call wrapper type.
+/// (7) A target object is the callable object held by a call wrapper.
+
+/// C++14 [func.require] 20.9.1
+///
+/// Define INVOKE (f, t1, t2, ..., tN) as follows:
+///   (1.1) — (t1.*f)(t2, ..., tN) when f is a pointer to a member function of a class T and t1 is an object of
+///   type T or a reference to an object of type T or a reference to an object of a type derived from T;
+///   (1.2) — ((*t1).*f)(t2, ..., tN) when f is a pointer to a member function of a class T and t1 is not one of
+///   the types described in the previous item;
+///   (1.3) — t1.*f when N == 1 and f is a pointer to member data of a class T and t1 is an object of type T or a
+///   reference to an object of type T or a reference to an object of a type derived from T;
+///   (1.4) — (*t1).*f when N == 1 and f is a pointer to member data of a class T and t1 is not one of the types
+///   described in the previous item;
+///   (1.5) — f(t1, t2, ..., tN) in all other cases.
+
+#include <functional>
+#include <type_traits>
+#include <cassert>
+
+struct NonCopyable {
+    NonCopyable() {}
+private:
+    NonCopyable(NonCopyable const&) = delete;
+    NonCopyable& operator=(NonCopyable const&) = delete;
+};
+
+struct TestClass {
+    explicit TestClass(int x) : data(x) {}
+
+    int& operator()(NonCopyable&&) & { return data; }
+    int const& operator()(NonCopyable&&) const & { return data; }
+    int volatile& operator()(NonCopyable&&) volatile & { return data; }
+    int const volatile& operator()(NonCopyable&&) const volatile & { return data; }
+
+    int&& operator()(NonCopyable&&) && { return std::move(data); }
+    int const&& operator()(NonCopyable&&) const && { return std::move(data); }
+    int volatile&& operator()(NonCopyable&&) volatile && { return std::move(data); }
+    int const volatile&& operator()(NonCopyable&&) const volatile && { return std::move(data); }
+
+    int data;
+private:
+    TestClass(TestClass const&) = delete;
+    TestClass& operator=(TestClass const&) = delete;
+};
+
+struct DerivedFromTestClass : public TestClass {
+    explicit DerivedFromTestClass(int x) : TestClass(x) {}
+};
+
+int& foo(NonCopyable&&) {
+    static int data = 42;
+    return data;
+}
+
+template <class Signature,  class Expect, class Functor>
+void test_b12(Functor&& f) {
+    // Create the callable object.
+    typedef Signature TestClass::*ClassFunc;
+    ClassFunc func_ptr = &TestClass::operator();
+
+    // Create the dummy arg.
+    NonCopyable arg;
+
+    // Check that the deduced return type of invoke is what is expected.
+    typedef decltype(
+        std::invoke(func_ptr, std::forward<Functor>(f), std::move(arg))
+    ) DeducedReturnType;
+    static_assert((std::is_same<DeducedReturnType, Expect>::value), "");
+
+    // Check that result_of_t matches Expect.
+    typedef typename std::result_of<ClassFunc&&(Functor&&, NonCopyable&&)>::type
+      ResultOfReturnType;
+    static_assert((std::is_same<ResultOfReturnType, Expect>::value), "");
+
+    // Run invoke and check the return value.
+    DeducedReturnType ret =
+            std::invoke(func_ptr, std::forward<Functor>(f), std::move(arg));
+    assert(ret == 42);
+}
+
+template <class Expect, class Functor>
+void test_b34(Functor&& f) {
+    // Create the callable object.
+    typedef int TestClass::*ClassFunc;
+    ClassFunc func_ptr = &TestClass::data;
+
+    // Check that the deduced return type of invoke is what is expected.
+    typedef decltype(
+        std::invoke(func_ptr, std::forward<Functor>(f))
+    ) DeducedReturnType;
+    static_assert((std::is_same<DeducedReturnType, Expect>::value), "");
+
+    // Check that result_of_t matches Expect.
+    typedef typename std::result_of<ClassFunc&&(Functor&&)>::type
+            ResultOfReturnType;
+    static_assert((std::is_same<ResultOfReturnType, Expect>::value), "");
+
+    // Run invoke and check the return value.
+    DeducedReturnType ret =
+            std::invoke(func_ptr, std::forward<Functor>(f));
+    assert(ret == 42);
+}
+
+template <class Expect, class Functor>
+void test_b5(Functor&& f) {
+    NonCopyable arg;
+
+    // Check that the deduced return type of invoke is what is expected.
+    typedef decltype(
+        std::invoke(std::forward<Functor>(f), std::move(arg))
+    ) DeducedReturnType;
+    static_assert((std::is_same<DeducedReturnType, Expect>::value), "");
+
+    // Check that result_of_t matches Expect.
+    typedef typename std::result_of<Functor&&(NonCopyable&&)>::type
+            ResultOfReturnType;
+    static_assert((std::is_same<ResultOfReturnType, Expect>::value), "");
+
+    // Run invoke and check the return value.
+    DeducedReturnType ret = std::invoke(std::forward<Functor>(f), std::move(arg));
+    assert(ret == 42);
+}
+
+void bullet_one_two_tests() {
+    {
+        TestClass cl(42);
+        test_b12<int&(NonCopyable&&) &, int&>(cl);
+        test_b12<int const&(NonCopyable&&) const &, int const&>(cl);
+        test_b12<int volatile&(NonCopyable&&) volatile &, int volatile&>(cl);
+        test_b12<int const volatile&(NonCopyable&&) const volatile &, int const volatile&>(cl);
+
+        test_b12<int&&(NonCopyable&&) &&, int&&>(std::move(cl));
+        test_b12<int const&&(NonCopyable&&) const &&, int const&&>(std::move(cl));
+        test_b12<int volatile&&(NonCopyable&&) volatile &&, int volatile&&>(std::move(cl));
+        test_b12<int const volatile&&(NonCopyable&&) const volatile &&, int const volatile&&>(std::move(cl));
+    }
+    {
+        DerivedFromTestClass cl(42);
+        test_b12<int&(NonCopyable&&) &, int&>(cl);
+        test_b12<int const&(NonCopyable&&) const &, int const&>(cl);
+        test_b12<int volatile&(NonCopyable&&) volatile &, int volatile&>(cl);
+        test_b12<int const volatile&(NonCopyable&&) const volatile &, int const volatile&>(cl);
+
+        test_b12<int&&(NonCopyable&&) &&, int&&>(std::move(cl));
+        test_b12<int const&&(NonCopyable&&) const &&, int const&&>(std::move(cl));
+        test_b12<int volatile&&(NonCopyable&&) volatile &&, int volatile&&>(std::move(cl));
+        test_b12<int const volatile&&(NonCopyable&&) const volatile &&, int const volatile&&>(std::move(cl));
+    }
+    {
+        TestClass cl_obj(42);
+        TestClass *cl = &cl_obj;
+        test_b12<int&(NonCopyable&&) &, int&>(cl);
+        test_b12<int const&(NonCopyable&&) const &, int const&>(cl);
+        test_b12<int volatile&(NonCopyable&&) volatile &, int volatile&>(cl);
+        test_b12<int const volatile&(NonCopyable&&) const volatile &, int const volatile&>(cl);
+    }
+    {
+        DerivedFromTestClass cl_obj(42);
+        DerivedFromTestClass *cl = &cl_obj;
+        test_b12<int&(NonCopyable&&) &, int&>(cl);
+        test_b12<int const&(NonCopyable&&) const &, int const&>(cl);
+        test_b12<int volatile&(NonCopyable&&) volatile &, int volatile&>(cl);
+        test_b12<int const volatile&(NonCopyable&&) const volatile &, int const volatile&>(cl);
+    }
+}
+
+void bullet_three_four_tests() {
+    {
+        typedef TestClass Fn;
+        Fn cl(42);
+        test_b34<int&>(cl);
+        test_b34<int const&>(static_cast<Fn const&>(cl));
+        test_b34<int volatile&>(static_cast<Fn volatile&>(cl));
+        test_b34<int const volatile&>(static_cast<Fn const volatile &>(cl));
+
+        test_b34<int&&>(static_cast<Fn &&>(cl));
+        test_b34<int const&&>(static_cast<Fn const&&>(cl));
+        test_b34<int volatile&&>(static_cast<Fn volatile&&>(cl));
+        test_b34<int const volatile&&>(static_cast<Fn const volatile&&>(cl));
+    }
+    {
+        typedef DerivedFromTestClass Fn;
+        Fn cl(42);
+        test_b34<int&>(cl);
+        test_b34<int const&>(static_cast<Fn const&>(cl));
+        test_b34<int volatile&>(static_cast<Fn volatile&>(cl));
+        test_b34<int const volatile&>(static_cast<Fn const volatile &>(cl));
+
+        test_b34<int&&>(static_cast<Fn &&>(cl));
+        test_b34<int const&&>(static_cast<Fn const&&>(cl));
+        test_b34<int volatile&&>(static_cast<Fn volatile&&>(cl));
+        test_b34<int const volatile&&>(static_cast<Fn const volatile&&>(cl));
+    }
+    {
+        typedef TestClass Fn;
+        Fn cl_obj(42);
+        Fn* cl = &cl_obj;
+        test_b34<int&>(cl);
+        test_b34<int const&>(static_cast<Fn const*>(cl));
+        test_b34<int volatile&>(static_cast<Fn volatile*>(cl));
+        test_b34<int const volatile&>(static_cast<Fn const volatile *>(cl));
+    }
+    {
+        typedef DerivedFromTestClass Fn;
+        Fn cl_obj(42);
+        Fn* cl = &cl_obj;
+        test_b34<int&>(cl);
+        test_b34<int const&>(static_cast<Fn const*>(cl));
+        test_b34<int volatile&>(static_cast<Fn volatile*>(cl));
+        test_b34<int const volatile&>(static_cast<Fn const volatile *>(cl));
+    }
+}
+
+void bullet_five_tests() {
+    using FooType = int&(NonCopyable&&);
+    {
+        FooType& fn = foo;
+        test_b5<int &>(fn);
+    }
+    {
+        FooType* fn = foo;
+        test_b5<int &>(fn);
+    }
+    {
+        typedef TestClass Fn;
+        Fn cl(42);
+        test_b5<int&>(cl);
+        test_b5<int const&>(static_cast<Fn const&>(cl));
+        test_b5<int volatile&>(static_cast<Fn volatile&>(cl));
+        test_b5<int const volatile&>(static_cast<Fn const volatile &>(cl));
+
+        test_b5<int&&>(static_cast<Fn &&>(cl));
+        test_b5<int const&&>(static_cast<Fn const&&>(cl));
+        test_b5<int volatile&&>(static_cast<Fn volatile&&>(cl));
+        test_b5<int const volatile&&>(static_cast<Fn const volatile&&>(cl));
+    }
+}
+
+int main() {
+    bullet_one_two_tests();
+    bullet_three_four_tests();
+    bullet_five_tests();
+}

www/cxx1z_status.html

 -->
   <tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n3911">N3911</a></td><td>LWG</td></td><td>TransformationTrait Alias <code>void_t</code>.</td><td>Urbana</td><td>Complete</td><td>3.6</td></tr>
   <tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4089">N4089</a></td><td>LWG</td></td><td>Safe conversions in <code>unique_ptr&lt;T[]&gt;</code>.</td><td>Urbana</td><td></td><td></td></tr>
-  <tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4169">N4169</a></td><td>LWG</td></td><td>A proposal to add invoke function template</td><td>Urbana</td><td></td><td></td></tr>
+  <tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4169">N4169</a></td><td>LWG</td></td><td>A proposal to add invoke function template</td><td>Urbana</td><td>Complete</td><td>3.6</td></tr>
   <tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4190">N4190</a></td></td><td>LWG</td><td>Removing auto_ptr, random_shuffle(), And Old <functional> Stuff.</td><td>Urbana</td><td></td><td></td></tr>
   <tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4258">N4258</a></td><td>LWG</td></td><td>Cleaning-up noexcept in the Library.</td><td>Urbana</td><td>In progress</td><td>3.7</td></tr>
   <tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4259">N4259</a></td><td>CWG</td></td><td>Wording for std::uncaught_exceptions</td><td>Urbana</td><td>Complete</td><td>3.7</td></tr>