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/*!
@file
Forward declares `boost::hana::drop_while`.
@copyright Louis Dionne 2013-2016
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_FWD_DROP_WHILE_HPP
#define BOOST_HANA_FWD_DROP_WHILE_HPP
#include <boost/hana/config.hpp>
#include <boost/hana/core/when.hpp>
BOOST_HANA_NAMESPACE_BEGIN
//! Drop elements from an iterable up to, but excluding, the first
//! element for which the `predicate` is not satisfied.
//! @ingroup group-Iterable
//!
//! Specifically, `drop_while` returns an iterable containing all the
//! elements of the original iterable except for those in the range
//! delimited by [`head`, `e`), where `head` is the first element and
//! `e` is the first element for which the `predicate` is not satisfied.
//! If the iterable is not finite, the `predicate` has to return a false-
//! valued `Logical` at a finite index for this method to return.
//!
//!
//! @param iterable
//! The iterable from which elements are dropped.
//!
//! @param predicate
//! A function called as `predicate(x)`, where `x` is an element of the
//! structure, and returning a `Logical` representing whether `x` should
//! be dropped from the structure. In the current version of the library,
//! `predicate` should return a compile-time `Logical`.
//!
//!
//! Example
//! -------
//! @include example/drop_while.cpp
#ifdef BOOST_HANA_DOXYGEN_INVOKED
constexpr auto drop_while = [](auto&& iterable, auto&& predicate) {
return tag-dispatched;
};
#else
template <typename It, typename = void>
struct drop_while_impl : drop_while_impl<It, when<true>> { };
struct drop_while_t {
template <typename Xs, typename Pred>
constexpr auto operator()(Xs&& xs, Pred&& pred) const;
};
constexpr drop_while_t drop_while{};
#endif
BOOST_HANA_NAMESPACE_END
#endif // !BOOST_HANA_FWDDROP_WHILE_HPP
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