#ifndef BOOST_LEAF_DETAIL_FUNCTION_TRAITS_HPP_INCLUDED
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#define BOOST_LEAF_DETAIL_FUNCTION_TRAITS_HPP_INCLUDED
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// Copyright (c) 2018-2020 Emil Dotchevski and Reverge Studios, Inc.
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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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#ifndef BOOST_LEAF_ENABLE_WARNINGS
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# if defined(__clang__)
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# pragma clang system_header
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# elif (__GNUC__*100+__GNUC_MINOR__>301)
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# pragma GCC system_header
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# elif defined(_MSC_VER)
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# pragma warning(push,1)
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# endif
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#endif
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#include <boost/leaf/detail/mp11.hpp>
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#include <tuple>
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namespace boost { namespace leaf {
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namespace leaf_detail
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{
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template<class...>
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struct gcc49_workaround //Thanks Glen Fernandes
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{
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using type = void;
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};
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template<class... T>
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using void_t = typename gcc49_workaround<T...>::type;
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template<class F,class V=void>
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struct function_traits
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{
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constexpr static int arity = -1;
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};
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template<class F>
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struct function_traits<F, void_t<decltype(&F::operator())>>
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{
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private:
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using tr = function_traits<decltype(&F::operator())>;
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public:
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using return_type = typename tr::return_type;
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static constexpr int arity = tr::arity - 1;
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using mp_args = typename leaf_detail_mp11::mp_rest<typename tr::mp_args>;
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template <int I>
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struct arg:
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tr::template arg<I+1>
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{
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};
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};
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template<class R, class... A>
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struct function_traits<R(A...)>
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{
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using return_type = R;
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static constexpr int arity = sizeof...(A);
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using mp_args = leaf_detail_mp11::mp_list<A...>;
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template <int I>
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struct arg
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{
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static_assert(I < arity, "I out of range");
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using type = typename std::tuple_element<I,std::tuple<A...>>::type;
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};
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};
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template<class F> struct function_traits<F&> : function_traits<F> { };
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template<class F> struct function_traits<F&&> : function_traits<F> { };
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template<class R, class... A> struct function_traits<R(*)(A...)> : function_traits<R(A...)> { };
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template<class R, class... A> struct function_traits<R(* &)(A...)> : function_traits<R(A...)> { };
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template<class R, class... A> struct function_traits<R(* const &)(A...)> : function_traits<R(A...)> { };
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template<class C, class R, class... A> struct function_traits<R(C::*)(A...)> : function_traits<R(C&,A...)> { };
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template<class C, class R, class... A> struct function_traits<R(C::*)(A...) const> : function_traits<R(C const &,A...)> { };
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template<class C, class R> struct function_traits<R(C::*)> : function_traits<R(C&)> { };
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template <class F>
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using fn_return_type = typename function_traits<F>::return_type;
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template <class F, int I>
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using fn_arg_type = typename function_traits<F>::template arg<I>::type;
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template <class F>
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using fn_mp_args = typename function_traits<F>::mp_args;
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}
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} }
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#endif
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