Edit: /usr/include/boost/hof/unpack.hpp (5588B)
/*=============================================================================
Copyright (c) 2015 Paul Fultz II
unpack.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_UNPACK_H
#define BOOST_HOF_GUARD_UNPACK_H
/// unpack
/// ======
///
/// Description
/// -----------
///
/// The `unpack` function adaptor takes a sequence and uses the elements of
/// the sequence for the arguments to the function. Multiple sequences can be
/// passed to the function. All elements from each sequence will be passed
/// into the function.
///
///
/// Synopsis
/// --------
///
/// template
/// unpack_adaptor unpack(F f);
///
/// Requirements
/// ------------
///
/// F must be:
///
/// * [ConstInvocable](ConstInvocable)
/// * MoveConstructible
///
/// Example
/// -------
///
/// #include
/// #include
/// using namespace boost::hof;
///
/// struct sum
/// {
/// template
/// T operator()(T x, U y) const
/// {
/// return x+y;
/// }
/// };
///
/// int main() {
/// int r = unpack(sum())(std::make_tuple(3,2));
/// assert(r == 5);
/// }
///
/// References
/// ----------
///
/// * [std::apply](http://en.cppreference.com/w/cpp/utility/apply) - C++17 function to unpack a tuple
/// * [`unpack_sequence`](unpack_sequence)
///
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
namespace boost { namespace hof {
namespace detail {
template
constexpr auto unpack_simple(F&& f, Sequence&& s) BOOST_HOF_RETURNS
(
detail::unpack_impl(BOOST_HOF_FORWARD(F)(f), BOOST_HOF_FORWARD(Sequence)(s))
)
template
constexpr auto unpack_join(F&& f, Sequences&&... s) BOOST_HOF_RETURNS
(
boost::hof::pack_join(unpack_simple(boost::hof::pack_forward, BOOST_HOF_FORWARD(Sequences)(s))...)(BOOST_HOF_FORWARD(F)(f))
);
}
template
struct unpack_adaptor : detail::callable_base
{
typedef unpack_adaptor fit_rewritable1_tag;
BOOST_HOF_INHERIT_CONSTRUCTOR(unpack_adaptor, detail::callable_base);
template
constexpr const detail::callable_base& base_function(Ts&&... xs) const noexcept
{
return boost::hof::always_ref(*this)(xs...);
}
struct unpack_failure
{
template
struct apply
{
struct deducer
{
template
typename Failure::template of operator()(Ts&&...) const;
};
template::value
)>::type>
static auto deduce(T&& x)
BOOST_HOF_RETURNS
(
boost::hof::detail::unpack_simple(deducer(), BOOST_HOF_FORWARD(T)(x))
);
template::value && BOOST_HOF_AND_UNPACK(is_unpackable::value)
)>::type>
static auto deduce(T&& x, Ts&&... xs) BOOST_HOF_RETURNS
(
boost::hof::detail::unpack_join(deducer(), BOOST_HOF_FORWARD(T)(x), BOOST_HOF_FORWARD(Ts)(xs)...)
);
#ifdef _MSC_VER
template
struct nop_failure;
template::value)
)>::type>
static as_failure deduce(Ts&&... xs);
#endif
template
struct of
#if (defined(__GNUC__) && !defined (__clang__) && __GNUC__ == 4 && __GNUC_MINOR__ < 7) || defined (_MSC_VER)
: std::enable_if()...))>::type
#else
: decltype(apply::deduce(std::declval()...))
#endif
{};
};
};
struct failure
: failure_map>
{};
BOOST_HOF_RETURNS_CLASS(unpack_adaptor);
template::value
)>::type>
constexpr auto operator()(T&& x) const
BOOST_HOF_RETURNS
(
boost::hof::detail::unpack_simple(BOOST_HOF_MANGLE_CAST(const detail::callable_base&)(BOOST_HOF_CONST_THIS->base_function(x)), BOOST_HOF_FORWARD(T)(x))
);
template::value && BOOST_HOF_AND_UNPACK(is_unpackable::value)
)>::type>
constexpr auto operator()(T&& x, Ts&&... xs) const BOOST_HOF_RETURNS
(
boost::hof::detail::unpack_join(BOOST_HOF_MANGLE_CAST(const detail::callable_base&)(BOOST_HOF_CONST_THIS->base_function(x)), BOOST_HOF_FORWARD(T)(x), BOOST_HOF_FORWARD(Ts)(xs)...)
);
};
BOOST_HOF_DECLARE_STATIC_VAR(unpack, detail::make);
}} // namespace boost::hof
#endif