adding interface example

fixing build errors

adding Boost to travis.yml

fixing travis.yml

fixing travis.yml

fixing travis.yml, fixing for libstdc++ bug

fixing travis.yml

fixing travis.yml

adding is_like_function

fixing interface example, doc gen

removing rogue tab characters

fixing build error

adding FunctionTypes section in documentation

removing empty note

fixing misspelling of inheritance

example/make_function_example.cpp

@@ -0,0 +1,54 @@
+/*<-
+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 <callable_traits/config.hpp>
+
+#ifdef CALLABLE_TRAITS_DISABLE_CONSTEXPR_CHECKS
+int main(){ return 0; }
+#else
+    
+//[ make_function_example
+#include <cassert>
+
+#include "make_function.hpp"
+
+using namespace example;
+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;
+    }
+};
+
+int main() {
+
+    // function pointer
+    auto f = make_function(&add);
+    assert(f(99, 1) == 100);
+
+    // function reference
+    f = make_function(add);
+    assert(f(99, 1) == 100);
+
+    // member function pointer (bound to object)
+    f = make_function(&adder::eval, adder{}, _1, _2);
+    assert(f(99, 1) == 100);
+
+    // lambda
+    f = make_function([](int i, int j) {
+        return i + j;
+    });
+
+    assert(f(99, 1) == 100);
+}
+//]
+#endif