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60625a6ef0
Allow reverse iteration of lowercase'd/uppercase'd chars
The PR implements `DoubleEndedIterator` trait for `ToLowercase` and `ToUppercase`.
This enables reverse iteration of lowercase/uppercase variants of character sequences.
One of use cases: determining whether a char sequence is a suffix of another one.
Example:
```rust
fn endswith_ignore_case(s1: &str, s2: &str) -> bool {
for eob in s1
.chars()
.flat_map(|c| c.to_lowercase())
.rev()
.zip_longest(s2.chars().flat_map(|c| c.to_lowercase()).rev())
{
match eob {
EitherOrBoth::Both(c1, c2) => {
if c1 != c2 {
return false;
}
}
EitherOrBoth::Left(_) => return true,
EitherOrBoth::Right(_) => return false,
}
}
true
}
```
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|---|---|---|
| .. | ||
| arc.rs | ||
| binary_heap.rs | ||
| borrow.rs | ||
| boxed.rs | ||
| btree_set_hash.rs | ||
| const_fns.rs | ||
| cow_str.rs | ||
| fmt.rs | ||
| heap.rs | ||
| lib.rs | ||
| linked_list.rs | ||
| rc.rs | ||
| slice.rs | ||
| str.rs | ||
| string.rs | ||
| vec_deque.rs | ||
| vec.rs | ||