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/*!
@file
Forward declares `boost::hana::intersperse`.
@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_INTERSPERSE_HPP
#define BOOST_HANA_FWD_INTERSPERSE_HPP
#include <boost/hana/config.hpp>
#include <boost/hana/core/when.hpp>
BOOST_HANA_NAMESPACE_BEGIN
//! Insert a value between each pair of elements in a finite sequence.
//! @ingroup group-Sequence
//!
//! Given a finite `Sequence` `xs` with a linearization of
//! `[x1, x2, ..., xn]`, `intersperse(xs, z)` is a new sequence with a
//! linearization of `[x1, z, x2, z, x3, ..., xn-1, z, xn]`. In other
//! words, it inserts the `z` element between every pair of elements of
//! the original sequence. If the sequence is empty or has a single
//! element, `intersperse` returns the sequence as-is. In all cases,
//! the sequence must be finite.
//!
//!
//! @param xs
//! The sequence in which a value is interspersed.
//!
//! @param z
//! The value to be inserted between every pair of elements of the sequence.
//!
//!
//! Example
//! -------
//! @include example/intersperse.cpp
#ifdef BOOST_HANA_DOXYGEN_INVOKED
constexpr auto intersperse = [](auto&& xs, auto&& z) {
return tag-dispatched;
};
#else
template <typename S, typename = void>
struct intersperse_impl : intersperse_impl<S, when<true>> { };
struct intersperse_t {
template <typename Xs, typename Z>
constexpr auto operator()(Xs&& xs, Z&& z) const;
};
constexpr intersperse_t intersperse{};
#endif
BOOST_HANA_NAMESPACE_END
#endif // !BOOST_HANA_FWD_INTERSPERSE_HPP
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