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/*!
@file
Forward declares `boost::hana::remove`.
@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_FWD_REMOVE_HPP
#define BOOST_HANA_FWD_REMOVE_HPP
#include <boost/hana/config.hpp>
#include <boost/hana/core/when.hpp>
BOOST_HANA_NAMESPACE_BEGIN
//! Remove all the elements of a monadic structure that are equal to some
//! value.
//! @ingroup group-MonadPlus
//!
//! Given a monadic structure `xs` and a `value`, `remove` returns a new
//! monadic structure equal to `xs` without all its elements that are
//! equal to the given `value`. `remove` is equivalent to `remove_if`
//! with the `equal.to(value)` predicate, i.e.
//! @code
//! remove(xs, value) == remove_if(xs, equal.to(value))
//! @endcode
//!
//!
//! Signature
//! ---------
//! Given a MonadPlus `M` and a value of type `T`, the signature is
//! \f$
//! \mathrm{remove} : M(T) \times T \to M(T)
//! \f$
//!
//! @param xs
//! A monadic structure to remove some elements from.
//!
//! @param value
//! A value that is compared to every element `x` of the structure.
//! Elements of the structure that are equal to that value are removed
//! from the structure. This requires every element to be Comparable
//! with `value`. Furthermore, in the current version of the library,
//! comparing `value` with any element of the structure must yield a
//! compile-time Logical.
//!
//!
//! Example
//! -------
//! @include example/remove.cpp
#ifdef BOOST_HANA_DOXYGEN_INVOKED
constexpr auto remove = [](auto&& xs, auto&& value) {
return tag-dispatched;
};
#else
template <typename M, typename = void>
struct remove_impl : remove_impl<M, when<true>> { };
struct remove_t {
template <typename Xs, typename Value>
constexpr auto operator()(Xs&& xs, Value&& value) const;
};
constexpr remove_t remove{};
#endif
BOOST_HANA_NAMESPACE_END
#endif // !BOOST_HANA_FWD_REMOVE_HPP
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