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/*=============================================================================
Copyright (c) 2015 Paul Fultz II
apply.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_APPLY_H
#define BOOST_HOF_GUARD_APPLY_H
/// apply
/// =====
///
/// Description
/// -----------
///
/// The `apply` function calls the function given to it with its arguments.
///
/// Synopsis
/// --------
///
/// template<class F, class... Ts>
/// constexpr auto apply(F&& f, Ts&&... xs);
///
/// Semantics
/// ---------
///
/// assert(apply(f)(xs...) == f(xs...));
/// assert(fold(apply, f)(x, y, z) == f(x)(y)(z));
///
/// Requirements
/// ------------
///
/// F must be:
///
/// * [Invocable](Invocable)
///
/// Example
/// -------
///
/// #include <boost/hof.hpp>
/// #include <cassert>
///
/// struct sum_f
/// {
/// template<class T, class U>
/// T operator()(T x, U y) const
/// {
/// return x+y;
/// }
/// };
///
/// int main() {
/// assert(boost::hof::apply(sum_f(), 1, 2) == 3);
/// }
///
#include <boost/hof/detail/result_of.hpp>
#include <boost/hof/detail/forward.hpp>
#include <boost/hof/detail/static_const_var.hpp>
#ifdef _MSC_VER
#pragma warning(push)
#pragma warning(disable: 4003)
#endif
#define BOOST_HOF_DETAIL_FOREACH_QUAL(m, data) \
m(, data) \
m(const, data) \
m(volatile, data) \
m(const volatile, data)
namespace boost { namespace hof {
namespace detail {
#if BOOST_HOF_HAS_MANUAL_DEDUCTION || BOOST_HOF_NO_EXPRESSION_SFINAE
struct apply_mem_fn
{
template<class...>
struct convertible_args;
template<class T, class U, class=void>
struct is_convertible_args
: std::false_type
{};
template<class... Ts, class... Us>
struct is_convertible_args<
convertible_args<Ts...>,
convertible_args<Us...>,
typename std::enable_if<(
sizeof...(Ts) == sizeof...(Us)
)>::type
>
: and_<std::is_convertible<Ts, Us>...>
{};
template<class From, class To>
struct is_compatible
: std::is_convertible<
typename std::add_pointer<typename std::remove_reference<From>::type>::type,
typename std::add_pointer<typename std::remove_reference<To>::type>::type
>
{};
#define BOOST_HOF_APPLY_MEM_FN_CALL(cv, data) \
template <class R, class Base, class Derived, class... Ts, class... Us, class=typename std::enable_if<and_< \
is_compatible<Derived, cv Base>, \
is_convertible_args<convertible_args<Us...>, convertible_args<Ts...>> \
>::value>::type> \
constexpr R operator()(R (Base::*mf)(Ts...) cv, Derived&& ref, Us &&... xs) const \
BOOST_HOF_RETURNS_DEDUCE_NOEXCEPT((BOOST_HOF_FORWARD(Derived)(ref).*mf)(BOOST_HOF_FORWARD(Us)(xs)...)) \
{ \
return (BOOST_HOF_FORWARD(Derived)(ref).*mf)(BOOST_HOF_FORWARD(Us)(xs)...); \
}
BOOST_HOF_DETAIL_FOREACH_QUAL(BOOST_HOF_APPLY_MEM_FN_CALL, ~)
};
struct apply_mem_data
{
template<class T, class R>
struct match_qualifier
{ typedef R type; };
#define BOOST_HOF_APPLY_MEM_DATA_MATCH(cv, ref) \
template<class T, class R> \
struct match_qualifier<cv T ref, R> \
: match_qualifier<T, cv R ref> \
{};
BOOST_HOF_DETAIL_FOREACH_QUAL(BOOST_HOF_APPLY_MEM_DATA_MATCH,&)
BOOST_HOF_DETAIL_FOREACH_QUAL(BOOST_HOF_APPLY_MEM_DATA_MATCH,&&)
template <class Base, class R, class Derived, class=typename std::enable_if<(
std::is_base_of<Base, typename std::decay<Derived>::type>::value
)>::type>
constexpr typename match_qualifier<Derived, R>::type
operator()(R Base::*pmd, Derived&& ref) const noexcept
{
return BOOST_HOF_FORWARD(Derived)(ref).*pmd;
}
};
template<class T, class U=decltype(*std::declval<T>())>
struct apply_deref
{ typedef U type; };
#endif
struct apply_f
{
#if BOOST_HOF_HAS_MANUAL_DEDUCTION || BOOST_HOF_NO_EXPRESSION_SFINAE
template<class F, class T, class... Ts, class=typename std::enable_if<(
std::is_member_function_pointer<typename std::decay<F>::type>::value
)>::type>
constexpr BOOST_HOF_SFINAE_MANUAL_RESULT(apply_mem_fn, id_<F>, id_<T>, id_<Ts>...)
operator()(F&& f, T&& obj, Ts&&... xs) const BOOST_HOF_SFINAE_MANUAL_RETURNS
(
apply_mem_fn()(f, BOOST_HOF_FORWARD(T)(obj), BOOST_HOF_FORWARD(Ts)(xs)...)
);
template<class F, class T, class... Ts, class U=typename apply_deref<T>::type, class=typename std::enable_if<(
std::is_member_function_pointer<typename std::decay<F>::type>::value
)>::type>
constexpr BOOST_HOF_SFINAE_MANUAL_RESULT(apply_mem_fn, id_<F>, id_<U>, id_<Ts>...)
operator()(F&& f, T&& obj, Ts&&... xs) const BOOST_HOF_SFINAE_MANUAL_RETURNS
(
apply_mem_fn()(f, *BOOST_HOF_FORWARD(T)(obj), BOOST_HOF_FORWARD(Ts)(xs)...)
);
template<class F, class T, class... Ts, class=typename std::enable_if<(
std::is_member_function_pointer<typename std::decay<F>::type>::value
)>::type>
constexpr BOOST_HOF_SFINAE_MANUAL_RESULT(apply_mem_fn, id_<F>, id_<T&>, id_<Ts>...)
operator()(F&& f, const std::reference_wrapper<T>& ref, Ts&&... xs) const BOOST_HOF_SFINAE_MANUAL_RETURNS
(
apply_mem_fn()(f, ref.get(), BOOST_HOF_FORWARD(Ts)(xs)...)
);
template<class F, class T, class=typename std::enable_if<(
std::is_member_object_pointer<typename std::decay<F>::type>::value
)>::type>
constexpr BOOST_HOF_SFINAE_MANUAL_RESULT(apply_mem_data, id_<F>, id_<T>)
operator()(F&& f, T&& obj) const BOOST_HOF_SFINAE_MANUAL_RETURNS
(
apply_mem_data()(f, BOOST_HOF_FORWARD(T)(obj))
);
template<class F, class T, class U=typename apply_deref<T>::type, class=typename std::enable_if<(
std::is_member_object_pointer<typename std::decay<F>::type>::value
)>::type>
constexpr BOOST_HOF_SFINAE_MANUAL_RESULT(apply_mem_data, id_<F>, id_<U>)
operator()(F&& f, T&& obj) const BOOST_HOF_SFINAE_MANUAL_RETURNS
(
apply_mem_data()(f, *BOOST_HOF_FORWARD(T)(obj))
);
template<class F, class T, class=typename std::enable_if<(
std::is_member_object_pointer<typename std::decay<F>::type>::value
)>::type>
constexpr BOOST_HOF_SFINAE_MANUAL_RESULT(apply_mem_data, id_<F>, id_<T&>)
operator()(F&& f, const std::reference_wrapper<T>& ref) const BOOST_HOF_SFINAE_MANUAL_RETURNS
(
apply_mem_data()(f, ref.get())
);
#else
template <class Base, class T, class Derived>
constexpr auto operator()(T Base::*pmd, Derived&& ref) const
BOOST_HOF_RETURNS(BOOST_HOF_FORWARD(Derived)(ref).*pmd);
template <class PMD, class Pointer>
constexpr auto operator()(PMD&& pmd, Pointer&& ptr) const
BOOST_HOF_RETURNS((*BOOST_HOF_FORWARD(Pointer)(ptr)).*BOOST_HOF_FORWARD(PMD)(pmd));
template <class Base, class T, class Derived>
constexpr auto operator()(T Base::*pmd, const std::reference_wrapper<Derived>& ref) const
BOOST_HOF_RETURNS(ref.get().*pmd);
template <class Base, class T, class Derived, class... Args>
constexpr auto operator()(T Base::*pmf, Derived&& ref, Args&&... args) const
BOOST_HOF_RETURNS((BOOST_HOF_FORWARD(Derived)(ref).*pmf)(BOOST_HOF_FORWARD(Args)(args)...));
template <class PMF, class Pointer, class... Args>
constexpr auto operator()(PMF&& pmf, Pointer&& ptr, Args&&... args) const
BOOST_HOF_RETURNS(((*BOOST_HOF_FORWARD(Pointer)(ptr)).*BOOST_HOF_FORWARD(PMF)(pmf))(BOOST_HOF_FORWARD(Args)(args)...));
template <class Base, class T, class Derived, class... Args>
constexpr auto operator()(T Base::*pmf, const std::reference_wrapper<Derived>& ref, Args&&... args) const
BOOST_HOF_RETURNS((ref.get().*pmf)(BOOST_HOF_FORWARD(Args)(args)...));
#endif
template<class F, class... Ts>
constexpr BOOST_HOF_SFINAE_MANUAL_RESULT(F, id_<Ts>...)
operator()(F&& f, Ts&&... xs) const BOOST_HOF_SFINAE_MANUAL_RETURNS
(
f(BOOST_HOF_FORWARD(Ts)(xs)...)
);
};
}
BOOST_HOF_DECLARE_STATIC_VAR(apply, detail::apply_f);
}} // namespace boost::hof
#ifdef _MSC_VER
#pragma warning(pop)
#endif
#endif
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