enumerate.h File Reference

jh::ranges::views::enumerate — sequence-aware enumerate adaptor. More...

#include "jh/ranges/views/zip.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::enumerate_fn	jh::ranges::views::enumerate {}
	The user-facing enumerate adaptor.

Detailed Description

jh::ranges::views::enumerate — sequence-aware enumerate adaptor.

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>

See also

jh::ranges::views::zip

This adaptor provides a Python-like enumerate view, implemented via jh::ranges::views::zip and std::views::iota. It pairs each element of a sequence with an increasing index.

Usage (same form as zip):

for (auto [i, v] : enumerate(seq)) { ... }       // start from 0
for (auto [i, v] : enumerate(seq, 10)) { ... }   // start from 10
for (auto [i, v] : seq | enumerate(5)) { ... }   // pipe form

About index type (diff_t):

• Deduced via jh::concepts::sequence_difference_t<std::remove_cvref_t<Seq>>.
• If the associated iterator defines a valid difference_type, or supports subtraction (it - it), that type is used (they must be consistent if both exist).
• If neither is available, the type falls back to std::ptrdiff_t.
• Conflicting iterator traits (mismatched difference_type and subtraction result) invalidate the type — such a type does not model jh::concepts::sequence.
• start is static_cast to diff_t; invalid conversions are ill-formed.

Note

Behavior, composition, and pipeline rules are identical to zip.

Version

1.3.x

Date

2025