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)> { ... }
}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
Doneif 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.
A Match result needs to contain the whole matched
pattern, however Reject results may be split up
into arbitrary many adjacent fragments. Both ranges may have zero length.
As an example, the pattern "aaa" and the haystack "cbaaaaab"
might produce the stream
[Reject(7, 8), Match(4, 7), Reject(1, 4), Reject(0, 1)].
Provided Methods§
Sourcefn next_match_back(&mut self) -> Option<(usize, usize)>
🔬This is a nightly-only experimental API. (pattern)
fn next_match_back(&mut self) -> Option<(usize, usize)>
pattern)Finds the next Match result.
See next_back().
Sourcefn next_reject_back(&mut self) -> Option<(usize, usize)>
🔬This is a nightly-only experimental API. (pattern)
fn next_reject_back(&mut self) -> Option<(usize, usize)>
pattern)Finds the next Reject result.
See next_back().