forked from boostorg/mp11
131 lines
3.2 KiB
C++
131 lines
3.2 KiB
C++
#ifndef BOOST_MP11_UTILITY_HPP_INCLUDED
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#define BOOST_MP11_UTILITY_HPP_INCLUDED
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// Copyright 2015, 2017 Peter Dimov.
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//
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// Distributed under the Boost Software License, Version 1.0.
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//
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// See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt
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#include <boost/mp11/integral.hpp>
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namespace boost
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{
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// mp_identity
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template<class T> struct mp_identity
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{
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using type = T;
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};
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// mp_identity_t
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template<class T> using mp_identity_t = T;
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// mp_inherit
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template<class... T> struct mp_inherit: T... {};
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// mp_if, mp_if_c
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namespace detail
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{
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template<bool C, class T, class E> struct mp_if_c_impl;
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template<class T, class E> struct mp_if_c_impl<true, T, E>
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{
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using type = T;
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};
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template<class T, class E> struct mp_if_c_impl<false, T, E>
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{
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using type = E;
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};
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} // namespace detail
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template<bool C, class T, class E> using mp_if_c = typename detail::mp_if_c_impl<C, T, E>::type;
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template<class C, class T, class E> using mp_if = typename detail::mp_if_c_impl<static_cast<bool>(C::value), T, E>::type;
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// mp_eval_if, mp_eval_if_c
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namespace detail
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{
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template<bool C, class T, template<class...> class F, class... U> struct mp_eval_if_c_impl;
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template<class T, template<class...> class F, class... U> struct mp_eval_if_c_impl<true, T, F, U...>
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{
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using type = T;
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};
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template<class T, template<class...> class F, class... U> struct mp_eval_if_c_impl<false, T, F, U...>
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{
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using type = F<U...>;
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};
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} // namespace detail
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template<bool C, class T, template<class...> class F, class... U> using mp_eval_if_c = typename detail::mp_eval_if_c_impl<C, T, F, U...>::type;
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template<class C, class T, template<class...> class F, class... U> using mp_eval_if = typename detail::mp_eval_if_c_impl<static_cast<bool>(C::value), T, F, U...>::type;
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// mp_valid
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// implementation by Bruno Dutra (by the name is_evaluable)
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namespace detail
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{
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template<template<class...> class F, class... T> struct mp_valid_impl
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{
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template<template<class...> class G, class = G<T...>> static mp_true check(int);
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template<template<class...> class> static mp_false check(...);
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using type = decltype(check<F>(0));
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};
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} // namespace detail
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template<template<class...> class F, class... T> using mp_valid = typename detail::mp_valid_impl<F, T...>::type;
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// mp_defer
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namespace detail
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{
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template<template<class...> class F, class... T> struct mp_defer_impl
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{
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using type = F<T...>;
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};
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struct mp_no_type
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{
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};
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} // namespace detail
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template<template<class...> class F, class... T> using mp_defer = mp_if<mp_valid<F, T...>, detail::mp_defer_impl<F, T...>, detail::mp_no_type>;
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// mp_quote
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template<template<class...> class F, class... T> struct mp_quote
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{
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template<class... U> using apply = F<T..., U...>;
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};
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// mp_unquote
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namespace detail
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{
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template<class Q, class... T> struct mp_unquote_impl
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{
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using type = typename Q::template apply<T...>;
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};
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template<template<class...> class F, class... T, class... U> struct mp_unquote_impl<mp_quote<F, T...>, U...>
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{
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using type = F<T..., U...>;
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};
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} // namespace detail
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template<class Q, class... T> using mp_unquote = typename detail::mp_unquote_impl<Q, T...>::type;
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} // namespace boost
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#endif // #ifndef BOOST_MP11_UTILITY_HPP_INCLUDED
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