renaming can_invoke to is_invokable

example/is_invokable_function_reference.cpp

@@ -0,0 +1,29 @@
+/*<-
+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)
+->*/
+
+//[ is_invokable_function_reference
+#include <callable_traits/callable_traits.hpp>
+
+namespace ct = callable_traits;
+
+int foo(int&& i) {
+    return i;
+}
+
+// is_invokable returns std::true_type here because the
+// arguments are valid to INVOKE
+static_assert(ct::is_invokable(foo, 0), "");
+
+int i = 0;
+
+// is_invokable returns std::false_type here because the
+// arguments are NOT valid to INVOKE - foo expects an
+// rvalue reference, not an lvalue reference.
+static_assert(!ct::is_invokable(foo, i), "");
+
+int main() {}
+//]
+