#ifndef BOOST_MP11_UTILITY_HPP_INCLUDED #define BOOST_MP11_UTILITY_HPP_INCLUDED // Copyright 2015-2020 Peter Dimov. // // 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 #include <boost/mp11/integral.hpp> #include <boost/mp11/detail/mp_list.hpp> #include <boost/mp11/detail/mp_fold.hpp> #include <boost/mp11/detail/mp_front.hpp> #include <boost/mp11/detail/mp_rename.hpp> #include <boost/mp11/detail/config.hpp> namespace boost { namespace mp11 { // mp_identity template<class T> struct mp_identity { using type = T; }; // mp_identity_t template<class T> using mp_identity_t = typename mp_identity<T>::type; // mp_inherit template<class... T> struct mp_inherit: T... {}; // mp_if, mp_if_c namespace detail { template<bool C, class T, class... E> struct mp_if_c_impl { }; template<class T, class... E> struct mp_if_c_impl<true, T, E...> { using type = T; }; template<class T, class E> struct mp_if_c_impl<false, T, E> { using type = E; }; } // namespace detail template<bool C, class T, class... E> using mp_if_c = typename detail::mp_if_c_impl<C, T, E...>::type; template<class C, class T, class... E> using mp_if = typename detail::mp_if_c_impl<static_cast<bool>(C::value), T, E...>::type; // mp_valid #if BOOST_MP11_WORKAROUND( BOOST_MP11_INTEL, != 0 ) // tested at 1800 // contributed by Roland Schulz in https://github.com/boostorg/mp11/issues/17 namespace detail { template<class...> using void_t = void; template<class, template<class...> class F, class... T> struct mp_valid_impl: mp_false {}; template<template<class...> class F, class... T> struct mp_valid_impl<void_t<F<T...>>, F, T...>: mp_true {}; } // namespace detail template<template<class...> class F, class... T> using mp_valid = typename detail::mp_valid_impl<void, F, T...>; #else // implementation by Bruno Dutra (by the name is_evaluable) namespace detail { template<template<class...> class F, class... T> struct mp_valid_impl { template<template<class...> class G, class = G<T...>> static mp_true check(int); template<template<class...> class> static mp_false check(...); using type = decltype(check<F>(0)); }; } // namespace detail template<template<class...> class F, class... T> using mp_valid = typename detail::mp_valid_impl<F, T...>::type; #endif template<class Q, class... T> using mp_valid_q = mp_valid<Q::template fn, T...>; // mp_defer namespace detail { template<template<class...> class F, class... T> struct mp_defer_impl { using type = F<T...>; }; struct mp_no_type { }; #if BOOST_MP11_WORKAROUND( BOOST_MP11_CUDA, >= 9000000 && BOOST_MP11_CUDA < 10000000 ) template<template<class...> class F, class... T> struct mp_defer_cuda_workaround { using type = mp_if<mp_valid<F, T...>, detail::mp_defer_impl<F, T...>, detail::mp_no_type>; }; #endif } // namespace detail #if BOOST_MP11_WORKAROUND( BOOST_MP11_CUDA, >= 9000000 && BOOST_MP11_CUDA < 10000000 ) template<template<class...> class F, class... T> using mp_defer = typename detail::mp_defer_cuda_workaround< F, T...>::type; #else 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>; #endif // mp_eval_if, mp_eval_if_c namespace detail { template<bool C, class T, template<class...> class F, class... U> struct mp_eval_if_c_impl; template<class T, template<class...> class F, class... U> struct mp_eval_if_c_impl<true, T, F, U...> { using type = T; }; template<class T, template<class...> class F, class... U> struct mp_eval_if_c_impl<false, T, F, U...>: mp_defer<F, U...> { }; } // namespace detail 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; 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; template<class C, class T, class Q, class... U> using mp_eval_if_q = typename detail::mp_eval_if_c_impl<static_cast<bool>(C::value), T, Q::template fn, U...>::type; // mp_eval_if_not template<class C, class T, template<class...> class F, class... U> using mp_eval_if_not = mp_eval_if<mp_not<C>, T, F, U...>; template<class C, class T, class Q, class... U> using mp_eval_if_not_q = mp_eval_if<mp_not<C>, T, Q::template fn, U...>; // mp_eval_or template<class T, template<class...> class F, class... U> using mp_eval_or = mp_eval_if_not<mp_valid<F, U...>, T, F, U...>; template<class T, class Q, class... U> using mp_eval_or_q = mp_eval_or<T, Q::template fn, U...>; // mp_valid_and_true template<template<class...> class F, class... T> using mp_valid_and_true = mp_eval_or<mp_false, F, T...>; template<class Q, class... T> using mp_valid_and_true_q = mp_valid_and_true<Q::template fn, T...>; // mp_cond // so elegant; so doesn't work // template<class C, class T, class... E> using mp_cond = mp_eval_if<C, T, mp_cond, E...>; namespace detail { template<class C, class T, class... E> struct mp_cond_impl; } // namespace detail template<class C, class T, class... E> using mp_cond = typename detail::mp_cond_impl<C, T, E...>::type; namespace detail { template<class C, class T, class... E> using mp_cond_ = mp_eval_if<C, T, mp_cond, E...>; template<class C, class T, class... E> struct mp_cond_impl: mp_defer<mp_cond_, C, T, E...> { }; } // namespace detail // mp_quote template<template<class...> class F> struct mp_quote { // the indirection through mp_defer works around the language inability // to expand T... into a fixed parameter list of an alias template template<class... T> using fn = typename mp_defer<F, T...>::type; }; // mp_quote_trait template<template<class...> class F> struct mp_quote_trait { template<class... T> using fn = typename F<T...>::type; }; // mp_invoke_q #if BOOST_MP11_WORKAROUND( BOOST_MP11_MSVC, < 1900 ) namespace detail { template<class Q, class... T> struct mp_invoke_q_impl: mp_defer<Q::template fn, T...> {}; } // namespace detail template<class Q, class... T> using mp_invoke_q = typename detail::mp_invoke_q_impl<Q, T...>::type; #elif BOOST_MP11_WORKAROUND( BOOST_MP11_GCC, < 50000 ) template<class Q, class... T> using mp_invoke_q = typename mp_defer<Q::template fn, T...>::type; #else template<class Q, class... T> using mp_invoke_q = typename Q::template fn<T...>; #endif // mp_not_fn<P> template<template<class...> class P> struct mp_not_fn { template<class... T> using fn = mp_not< mp_invoke_q<mp_quote<P>, T...> >; }; template<class Q> using mp_not_fn_q = mp_not_fn<Q::template fn>; // mp_compose namespace detail { template<class L, class Q> using mp_compose_helper = mp_list< mp_apply_q<Q, L> >; } // namespace detail #if !BOOST_MP11_WORKAROUND( BOOST_MP11_MSVC, < 1900 ) template<template<class...> class... F> struct mp_compose { template<class... T> using fn = mp_front< mp_fold<mp_list<mp_quote<F>...>, mp_list<T...>, detail::mp_compose_helper> >; }; #endif template<class... Q> struct mp_compose_q { template<class... T> using fn = mp_front< mp_fold<mp_list<Q...>, mp_list<T...>, detail::mp_compose_helper> >; }; } // namespace mp11 } // namespace boost #endif // #ifndef BOOST_MP11_UTILITY_HPP_INCLUDED