pub unsafe trait ReverseSearcher<'a>: Searcher<'a> {
// Required method
fn next_back(&mut self) -> SearchStep;
// Provided methods
fn next_match_back(&mut self) -> Option<(usize, usize)> { ... }
fn next_reject_back(&mut self) -> Option<(usize, usize)> { ... }
}
🔬This is a nightly-only experimental API. (
pattern
)Expand description
A reverse searcher for a string pattern.
This trait provides methods for searching for non-overlapping matches of a pattern starting from the back (right) of a string.
It will be implemented by associated Searcher
types of the Pattern
trait if the pattern supports searching
for it from the back.
The index ranges returned by this trait are not required to exactly match those of the forward search in reverse.
For the reason why this trait is marked unsafe, see the
parent trait Searcher
.
Required Methods§
sourcefn next_back(&mut self) -> SearchStep
🔬This is a nightly-only experimental API. (pattern
)
fn next_back(&mut self) -> SearchStep
pattern
)Performs the next search step starting from the back.
- Returns
Match(a, b)
ifhaystack[a..b]
matches the pattern. - Returns
Reject(a, b)
ifhaystack[a..b]
can not match the pattern, even partially. - Returns
Done
if every byte of the haystack has been visited
The stream of Match
and
Reject
values up to a Done
will contain index ranges that are adjacent, non-overlapping,
covering the whole haystack, and laying on utf8 boundaries.