stabilize build system: depends, installer, boost/bdb fixes, cross targets groundwork
This commit is contained in:
@@ -0,0 +1,105 @@
|
||||
/*!
|
||||
@file
|
||||
Defines `boost::hana::partial`.
|
||||
|
||||
@copyright Louis Dionne 2013-2017
|
||||
Distributed under the Boost Software License, Version 1.0.
|
||||
(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
|
||||
*/
|
||||
|
||||
#ifndef BOOST_HANA_FUNCTIONAL_PARTIAL_HPP
|
||||
#define BOOST_HANA_FUNCTIONAL_PARTIAL_HPP
|
||||
|
||||
#include <boost/hana/basic_tuple.hpp>
|
||||
#include <boost/hana/config.hpp>
|
||||
#include <boost/hana/detail/decay.hpp>
|
||||
|
||||
#include <cstddef>
|
||||
#include <utility>
|
||||
|
||||
|
||||
BOOST_HANA_NAMESPACE_BEGIN
|
||||
//! @ingroup group-functional
|
||||
//! Partially apply a function to some arguments.
|
||||
//!
|
||||
//! Given a function `f` and some arguments, `partial` returns a new
|
||||
//! function corresponding to the partially applied function `f`. This
|
||||
//! allows providing some arguments to a function and letting the rest
|
||||
//! of the arguments be provided later. Specifically, `partial(f, x...)`
|
||||
//! is a function such that
|
||||
//! @code
|
||||
//! partial(f, x...)(y...) == f(x..., y...)
|
||||
//! @endcode
|
||||
//!
|
||||
//! @note
|
||||
//! The arity of `f` must match the total number of arguments passed to
|
||||
//! it, i.e. `sizeof...(x) + sizeof...(y)`.
|
||||
//!
|
||||
//!
|
||||
//! Example
|
||||
//! -------
|
||||
//! @include example/functional/partial.cpp
|
||||
#ifdef BOOST_HANA_DOXYGEN_INVOKED
|
||||
constexpr auto partial = [](auto&& f, auto&& ...x) {
|
||||
return [perfect-capture](auto&& ...y) -> decltype(auto) {
|
||||
return forwarded(f)(forwarded(x)..., forwarded(y)...);
|
||||
};
|
||||
};
|
||||
#else
|
||||
template <typename Indices, typename F, typename ...X>
|
||||
struct partial_t;
|
||||
|
||||
struct make_partial_t {
|
||||
struct secret { };
|
||||
template <typename F, typename ...X>
|
||||
constexpr partial_t<
|
||||
std::make_index_sequence<sizeof...(X)>,
|
||||
typename detail::decay<F>::type,
|
||||
typename detail::decay<X>::type...
|
||||
>
|
||||
operator()(F&& f, X&& ...x) const {
|
||||
return {secret{}, static_cast<F&&>(f), static_cast<X&&>(x)...};
|
||||
}
|
||||
};
|
||||
|
||||
template <std::size_t ...n, typename F, typename ...X>
|
||||
struct partial_t<std::index_sequence<n...>, F, X...> {
|
||||
partial_t() = default;
|
||||
|
||||
template <typename ...T>
|
||||
constexpr partial_t(make_partial_t::secret, T&& ...t)
|
||||
: storage_{static_cast<T&&>(t)...}
|
||||
{ }
|
||||
|
||||
basic_tuple<F, X...> storage_;
|
||||
|
||||
template <typename ...Y>
|
||||
constexpr decltype(auto) operator()(Y&& ...y) const& {
|
||||
return hana::at_c<0>(storage_)(
|
||||
hana::at_c<n+1>(storage_)...,
|
||||
static_cast<Y&&>(y)...
|
||||
);
|
||||
}
|
||||
|
||||
template <typename ...Y>
|
||||
constexpr decltype(auto) operator()(Y&& ...y) & {
|
||||
return hana::at_c<0>(storage_)(
|
||||
hana::at_c<n+1>(storage_)...,
|
||||
static_cast<Y&&>(y)...
|
||||
);
|
||||
}
|
||||
|
||||
template <typename ...Y>
|
||||
constexpr decltype(auto) operator()(Y&& ...y) && {
|
||||
return static_cast<F&&>(hana::at_c<0>(storage_))(
|
||||
static_cast<X&&>(hana::at_c<n+1>(storage_))...,
|
||||
static_cast<Y&&>(y)...
|
||||
);
|
||||
}
|
||||
};
|
||||
|
||||
constexpr make_partial_t partial{};
|
||||
#endif
|
||||
BOOST_HANA_NAMESPACE_END
|
||||
|
||||
#endif // !BOOST_HANA_FUNCTIONAL_PARTIAL_HPP
|
||||
Reference in New Issue
Block a user