/*=============================================================================
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Copyright (c) 2014 Paul Fultz II
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is_invocable.h
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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==============================================================================*/
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#ifndef BOOST_HOF_GUARD_IS_CALLABLE_H
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#define BOOST_HOF_GUARD_IS_CALLABLE_H
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/// is_invocable
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/// ===========
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///
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/// Description
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/// -----------
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///
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/// The `is_invocable` metafunction checks if the function is callable with
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/// certain parameters.
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///
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/// Requirements
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/// ------------
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///
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/// F must be:
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///
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/// * [Invocable](Invocable)
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///
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/// Synopsis
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/// --------
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///
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/// template<class F, class... Ts>
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/// struct is_invocable;
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///
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/// Example
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/// -------
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///
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/// #include <boost/hof.hpp>
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/// using namespace boost::hof;
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///
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/// struct is_invocable_class
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/// {
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/// void operator()(int) const
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/// {
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/// }
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/// };
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/// static_assert(is_invocable<is_invocable_class, int>(), "Not callable");
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///
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/// int main() {}
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///
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#include <boost/hof/detail/can_be_called.hpp>
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#include <boost/hof/apply.hpp>
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namespace boost { namespace hof {
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template<class F, class... Ts>
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struct is_invocable
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: detail::can_be_called<detail::apply_f, F, Ts...>
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{};
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template<class F, class... Ts, class... Us>
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struct is_invocable<F(Ts...), Us...>
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{
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static_assert(!std::is_same<F, F>::value,
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"The is_invocable<F(Args...)> form is not supported because it is problematic."
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"Please use is_invocable<F, Args...> instead."
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);
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};
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}} // namespace boost::hof
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#endif
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