Edit: /usr/include/boost/hana/drop_while.hpp (3174B)
/*!
@file
Defines `boost::hana::drop_while`.
@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_DROP_WHILE_HPP
#define BOOST_HANA_DROP_WHILE_HPP
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
BOOST_HANA_NAMESPACE_BEGIN
//! @cond
template
constexpr auto drop_while_t::operator()(Xs&& xs, Pred&& pred) const {
using It = typename hana::tag_of::type;
using DropWhile = BOOST_HANA_DISPATCH_IF(drop_while_impl,
hana::Iterable::value
);
#ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
static_assert(hana::Iterable::value,
"hana::drop_while(xs, pred) requires 'xs' to be an Iterable");
#endif
return DropWhile::apply(static_cast(xs), static_cast(pred));
}
//! @endcond
namespace iterable_detail {
struct drop_while_helper {
struct next {
template
constexpr decltype(auto) operator()(Xs&& xs, Pred&& pred) const {
return hana::drop_while(
hana::drop_front(static_cast(xs)),
static_cast(pred)
);
}
};
template
constexpr decltype(auto) operator()(Xs&& xs, Pred&& pred) const {
return hana::eval_if(pred(hana::front(xs)),
hana::make_lazy(next{})(xs, pred),
hana::make_lazy(xs)
);
}
};
}
template
struct drop_while_impl> : default_ {
template
static constexpr auto apply(Xs&& xs, Pred&& pred) {
return hana::eval_if(hana::is_empty(xs),
hana::make_lazy(xs),
hana::make_lazy(iterable_detail::drop_while_helper{})(
xs, static_cast(pred))
);
}
};
template
struct drop_while_impl::value>> {
template
static constexpr auto apply(Xs&& xs, Pred&&) {
using FirstUnsatisfied = decltype(
hana::unpack(static_cast(xs),
detail::first_unsatisfied_index{})
);
return hana::drop_front(static_cast(xs),
FirstUnsatisfied{});
}
};
BOOST_HANA_NAMESPACE_END
#endif // !BOOST_HANA_DROP_WHILE_HPP