flatten.h File Reference

View adaptor for flattening tuple-like elements in a range. More...

#include <ranges>
#include "jh/metax/flatten_proxy.h"
#include "jh/ranges/views/transform.h"

Go to the source code of this file.

Namespaces
namespace	jh::ranges
	Semantic pipeline namespace for JH range operations.
namespace	jh::ranges::views
	Range view adaptor implementations with explicit semantic control.

Variables
constexpr detail::flatten_fn	jh::ranges::views::flatten {}
	User-facing flatten adaptor.

Detailed Description

View adaptor for flattening tuple-like elements in a range.

Copyright

Copyright 2025 JeongHan-Bae <mastropseudo@gmail.com>
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

Full license: GitHub

Author

JeongHan-Bae <mastropseudo@gmail.com>

The jh::ranges::views::flatten adaptor produces a lazy view that inspects each element of a range and, if it models jh::concepts::tuple_like, wraps it in a jh::meta::flatten_proxy. Non-tuple-like elements are forwarded unchanged.

Behavior

• Tuple-like elements are recursively flattened into jh::meta::flatten_proxy objects.
• Non-tuple-like elements are passed through as-is.
• The transformation is applied lazily; no element is copied or expanded eagerly.

Implementation Notes

• flatten delegates to jh::ranges::views::transform.
• jh::ranges::views::transform internally decides whether to construct a non-consuming or consuming transformation view depending on the behavior of the projection function.
• Because flatten is a pure observation, its output preserves the consumption property of the underlying range: if the input is non-consuming, the output remains non-consuming; if the input is single-pass, the result is also single-pass.

Version

1.3.x

Date

2025