pub unsafe trait Searcher<'a> {
// Required methods
fn haystack(&self) -> &'a str;
fn next(&mut self) -> SearchStep;
// Provided methods
fn next_match(&mut self) -> Option<(usize, usize)> { ... }
fn next_reject(&mut self) -> Option<(usize, usize)> { ... }
}pattern #27721)Expand description
A searcher for a string pattern.
This trait provides methods for searching for non-overlapping matches of a pattern starting from the front (left) of a string.
It will be implemented by associated Searcher
types of the Pattern trait.
The trait is marked unsafe because the indices returned by the
next() methods are required to lie on valid utf8
boundaries in the haystack. This enables consumers of this trait to
slice the haystack without additional runtime checks.
Required Methods§
sourcefn haystack(&self) -> &'a str
🔬This is a nightly-only experimental API. (pattern #27721)
fn haystack(&self) -> &'a str
pattern #27721)Getter for the underlying string to be searched in
Will always return the same &str.
sourcefn next(&mut self) -> SearchStep
🔬This is a nightly-only experimental API. (pattern #27721)
fn next(&mut self) -> SearchStep
pattern #27721)Performs the next search step starting from the front.
- 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(0, 1), Reject(1, 2), Match(2, 5), Reject(5, 8)]
Provided Methods§
sourcefn next_match(&mut self) -> Option<(usize, usize)>
🔬This is a nightly-only experimental API. (pattern #27721)
fn next_match(&mut self) -> Option<(usize, usize)>
pattern #27721)Finds the next Match result. See next().
Unlike next(), there is no guarantee that the returned ranges
of this and next_reject will overlap. This will return
(start_match, end_match), where start_match is the index of where
the match begins, and end_match is the index after the end of the match.
sourcefn next_reject(&mut self) -> Option<(usize, usize)>
🔬This is a nightly-only experimental API. (pattern #27721)
fn next_reject(&mut self) -> Option<(usize, usize)>
pattern #27721)Finds the next Reject result. See next()
and next_match().
Unlike next(), there is no guarantee that the returned ranges
of this and next_match will overlap.