cleaning up interface, adding std_function example

example/std_function/example.cpp

@@ -0,0 +1,52 @@
+/*
+
+Copyright Barrett Adair 2015
+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>
+#undef NDEBUG
+#include "make_function.hpp"
+
+using example::make_function;
+using namespace std::placeholders;
+
+int add(int i, int j) {
+    return i + j;
+}
+
+struct adder {
+
+    int eval(int i, int j) const {
+        return i + j;
+    }
+};
+
+void check_add(std::function<int(int, int)> f) {
+
+    auto add_result = f(99, 1);
+    assert(add_result == 100);
+}
+
+int main() {
+
+    //function pointer
+    auto f = make_function(&add);
+    check_add(f);
+
+    //function reference
+    f = make_function(add);
+    check_add(f);
+
+    //lambda
+    f = make_function([](int i, int j) {
+        return i + j;
+    });
+    check_add(f);
+
+    //member function pointer (bound to object)
+    f = make_function(&adder::eval, adder{}, _1, _2);
+    check_add(f);
+}

example/std_function/make_function.hpp

@@ -0,0 +1,40 @@
+#include <functional>
+#include <callable_traits/callable_traits.hpp>
+
+#ifndef EXAMPLE_ADAPTORS_HPP
+#define EXAMPLE_ADAPTORS_HPP
+
+namespace example {
+
+    namespace ct = callable_traits;
+
+    //`make_function` turns any (non-overloaded) callable into std::function
+    template<typename T>
+    inline decltype(auto) make_function(T&& t) {
+        using signature = ct::function_type<T&&>;
+        using result_type = std::function<signature>;
+        return result_type{ ::std::forward<T>(t) };
+    }
+
+    //this `make_function` overload turns a bind expression into std::function
+    template<typename T, typename First, typename... Others>
+    inline decltype(auto) make_function(T&& t, First&& first, Others&&... others) {
+
+        using bind_expr = decltype(::callable_traits::bind(
+            ::std::forward<T>(t),
+            ::std::forward<First>(first),
+            ::std::forward<Others>(others)...
+        ));
+
+        using signature = ct::function_type<bind_expr>;
+        using result_type = std::function<signature>;
+
+        return result_type{ ::std::bind(
+            ::std::forward<T>(t),
+            ::std::forward<First>(first),
+            ::std::forward<Others>(others)...
+        )};
+    }
+}
+
+#endif