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diff --git a/boost/hof/detail/callable_base.hpp b/boost/hof/detail/callable_base.hpp
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+++ b/boost/hof/detail/callable_base.hpp
@@ -0,0 +1,65 @@
+/*=============================================================================
+    Copyright (c) 2015 Paul Fultz II
+    callable_base.h
+    Distributed under the Boost Software License, Version 1.0. (See accompanying
+    file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+==============================================================================*/
+
+#ifndef BOOST_HOF_GUARD_CALLABLE_BASE_H
+#define BOOST_HOF_GUARD_CALLABLE_BASE_H
+
+#include <boost/hof/detail/delegate.hpp>
+#include <boost/hof/detail/result_of.hpp>
+#include <boost/hof/apply.hpp>
+
+#ifndef BOOST_HOF_CALLABLE_BASE_USE_TEMPLATE_ALIAS
+#if (defined(__GNUC__) && !defined (__clang__) && __GNUC__ == 4 && __GNUC_MINOR__ < 7)
+#define BOOST_HOF_CALLABLE_BASE_USE_TEMPLATE_ALIAS 0
+#else
+#define BOOST_HOF_CALLABLE_BASE_USE_TEMPLATE_ALIAS 1
+#endif
+#endif
+
+namespace boost { namespace hof { namespace detail {
+
+template<class F>
+struct non_class_function
+{
+    F f;
+    BOOST_HOF_DELEGATE_CONSTRUCTOR(non_class_function, F, f)
+
+    template<class... Ts>
+    constexpr BOOST_HOF_SFINAE_RESULT(apply_f, id_<F>, id_<Ts>...) 
+    operator()(Ts&&... xs) const BOOST_HOF_SFINAE_RETURNS
+    (
+        boost::hof::apply(f, BOOST_HOF_FORWARD(Ts)(xs)...)
+    );
+};
+
+template<class F>
+struct callable_base_type
+: std::conditional<(BOOST_HOF_IS_CLASS(F) && !BOOST_HOF_IS_FINAL(F) && !BOOST_HOF_IS_POLYMORPHIC(F)), F, non_class_function<F>>
+{};
+
+#if BOOST_HOF_CALLABLE_BASE_USE_TEMPLATE_ALIAS
+template<class F>
+using callable_base = typename callable_base_type<F>::type;
+#else
+template<class F>
+struct callable_base
+: callable_base_type<F>::type
+{
+    typedef typename callable_base_type<F>::type base;
+    BOOST_HOF_INHERIT_CONSTRUCTOR(callable_base, base)
+};
+
+template<class F>
+struct callable_base_type<callable_base<F>>
+: callable_base_type<F>
+{};
+
+#endif
+
+}}} // namespace boost::hof
+
+#endif