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- /*!
- @file
- Forward declares `boost::hana::insert`.
- @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_INSERT_HPP
- #define BOOST_HANA_FWD_INSERT_HPP
- #include <boost/hana/config.hpp>
- #include <boost/hana/core/when.hpp>
- BOOST_HANA_NAMESPACE_BEGIN
- // Note: This function is documented per datatype/concept only.
- //! @cond
- template <typename T, typename = void>
- struct insert_impl : insert_impl<T, when<true>> { };
- //! @endcond
- struct insert_t {
- template <typename Set, typename ...Args>
- constexpr decltype(auto) operator()(Set&& set, Args&& ...args) const;
- };
- constexpr insert_t insert{};
- //! Insert a value at a given index in a sequence.
- //! @ingroup group-Sequence
- //!
- //! Given a sequence, an index and an element to insert, `insert` inserts
- //! the element at the given index.
- //!
- //! @param xs
- //! The sequence in which a value should be inserted.
- //!
- //! @param n
- //! The index at which an element should be inserted. This must be a
- //! non-negative `Constant` of an integral type, and it must also be
- //! true that `n < length(xs)` if `xs` is a finite sequence.
- //!
- //! @param element
- //! The element to insert in the sequence.
- //!
- //!
- //! Example
- //! -------
- //! @include example/insert.cpp
- #ifdef BOOST_HANA_DOXYGEN_INVOKED
- constexpr auto insert = [](auto&& xs, auto&& n, auto&& element) {
- return tag-dispatched;
- };
- #endif
- BOOST_HANA_NAMESPACE_END
- #endif // !BOOST_HANA_FWD_INSERT_HPP
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