axmol/thirdparty/range-v3/include/range/v3/view/for_each.hpp

139 lines
3.6 KiB
C++

/// \file
// Range v3 library
//
// Copyright Eric Niebler 2014-present
//
// Use, modification and distribution is subject to the
// Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
// Project home: https://github.com/ericniebler/range-v3
//
#ifndef RANGES_V3_VIEW_FOR_EACH_HPP
#define RANGES_V3_VIEW_FOR_EACH_HPP
#include <utility>
#include <meta/meta.hpp>
#include <range/v3/range_fwd.hpp>
#include <range/v3/functional/bind_back.hpp>
#include <range/v3/functional/invoke.hpp>
#include <range/v3/utility/static_const.hpp>
#include <range/v3/view/all.hpp>
#include <range/v3/view/generate_n.hpp>
#include <range/v3/view/join.hpp>
#include <range/v3/view/repeat_n.hpp>
#include <range/v3/view/single.hpp>
#include <range/v3/view/transform.hpp>
#include <range/v3/view/view.hpp>
#include <range/v3/detail/prologue.hpp>
namespace ranges
{
/// \addtogroup group-views
/// @{
namespace views
{
/// Lazily applies an unary function to each element in the source
/// range that returns another range (possibly empty), flattening
/// the result.
struct for_each_base_fn
{
template(typename Rng, typename Fun)(
requires viewable_range<Rng> AND transformable_range<Rng, Fun> AND
joinable_range<transform_view<all_t<Rng>, Fun>>)
constexpr auto operator()(Rng && rng, Fun fun) const
{
return join(transform(static_cast<Rng &&>(rng), std::move(fun)));
}
};
struct for_each_fn : for_each_base_fn
{
using for_each_base_fn::operator();
template<typename Fun>
constexpr auto operator()(Fun fun) const
{
return make_view_closure(bind_back(for_each_base_fn{}, std::move(fun)));
}
};
/// \relates for_each_fn
RANGES_INLINE_VARIABLE(for_each_fn, for_each)
} // namespace views
struct yield_fn
{
template(typename V)(
requires copy_constructible<V>)
single_view<V> operator()(V v) const
{
return views::single(std::move(v));
}
};
/// \relates yield_fn
RANGES_INLINE_VARIABLE(yield_fn, yield)
struct yield_from_fn
{
template(typename Rng)(
requires view_<Rng>)
Rng operator()(Rng rng) const
{
return rng;
}
};
/// \relates yield_from_fn
RANGES_INLINE_VARIABLE(yield_from_fn, yield_from)
struct yield_if_fn
{
template<typename V>
repeat_n_view<V> operator()(bool b, V v) const
{
return views::repeat_n(std::move(v), b ? 1 : 0);
}
};
/// \relates yield_if_fn
RANGES_INLINE_VARIABLE(yield_if_fn, yield_if)
struct lazy_yield_if_fn
{
template(typename F)(
requires invocable<F &>)
generate_n_view<F> operator()(bool b, F f) const
{
return views::generate_n(std::move(f), b ? 1 : 0);
}
};
/// \relates lazy_yield_if_fn
RANGES_INLINE_VARIABLE(lazy_yield_if_fn, lazy_yield_if)
/// @}
/// \cond
template(typename Rng, typename Fun)(
requires viewable_range<Rng> AND views::transformable_range<Rng, Fun> AND
input_range<invoke_result_t<Fun &, range_reference_t<Rng>>>)
auto
operator>>=(Rng && rng, Fun fun)
{
return views::for_each(static_cast<Rng &&>(rng), std::move(fun));
}
/// \endcond
} // namespace ranges
#include <range/v3/detail/epilogue.hpp>
#endif