cleaning up interface, adding std_function example

example/bind/example1.cpp

@@ -0,0 +1,77 @@
+/*
+
+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)
+
+*/
+
+#include <cassert>
+#include <type_traits>
+#include <functional>
+#include <tuple>
+#include <callable_traits/callable_traits.hpp>
+
+struct Vampire {};
+struct Robot {};
+struct Animal {};
+struct Dog : Animal {};
+struct Poodle : Dog {};
+struct ScaryMonster : Vampire, Robot, Poodle {};
+
+auto vampire_to_robot(Vampire) {
+    return Robot{};
+}
+
+auto robot_to_dog = [](Robot){
+    return Dog{};
+};
+
+struct converter {
+    auto dog_to_vampire(Dog) {
+        return Vampire{};
+    }
+};
+
+int take_all(Vampire, Robot, Animal, Dog, Poodle, ScaryMonster) {
+    return 0;
+}
+
+using namespace std::placeholders;
+namespace ct = callable_traits;
+
+int main() {
+
+    auto b =
+        ct::bind(&take_all,
+            ct::bind(&converter::dog_to_vampire,
+                converter{},
+                ct::bind(robot_to_dog,
+                    ct::bind(&vampire_to_robot, _1)
+                )
+            ),
+            ct::bind(&vampire_to_robot, _3),
+            Animal{},
+            _1,
+            _2,
+            _1
+        );
+
+    // the last _1 placeholder in this bind expression forces
+    // all other _1 slots to accept ScaryMonster, the
+    // narrowest of all _1 parameters.
+
+    {
+        using args = ct::args<decltype(b)>;
+        using expect = std::tuple<ScaryMonster, Poodle, Vampire>;
+        static_assert(std::is_same<args, expect>::value, "");
+    } {
+        using type = ct::function_type<decltype(b)>;
+        using expect = int(ScaryMonster, Poodle, Vampire);
+        static_assert(std::is_same<type, expect>::value, "");
+    }
+
+    assert(b(ScaryMonster{}, Poodle{}, Vampire{}) == 0);
+
+    return 0;
+}