rustworkx_core/
utils.rs

1// Licensed under the Apache License, Version 2.0 (the "License"); you may
2// not use this file except in compliance with the License. You may obtain
3// a copy of the License at
4//
5//     http://www.apache.org/licenses/LICENSE-2.0
6//
7// Unless required by applicable law or agreed to in writing, software
8// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
9// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
10// License for the specific language governing permissions and limitations
11// under the License.
12
13use std::iter;
14
15pub fn pairwise<I>(right: I) -> impl Iterator<Item = (Option<I::Item>, I::Item)>
16where
17    I: IntoIterator + Clone,
18{
19    let left = iter::once(None).chain(right.clone().into_iter().map(Some));
20    left.zip(right)
21}