Trait core::str::pattern::ReverseSearcher [] [src]

pub unsafe trait ReverseSearcher<'a>: Searcher<'a> {
    fn next_back(&mut self) -> SearchStep;

    fn next_match_back(&mut self) -> Option<(usize, usize)> { ... }
    fn next_reject_back(&mut self) -> Option<(usize, usize)> { ... }
}
Unstable

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`Searchertypes of the` types of the Pattern`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 them parent trait Searcher`Searcher`.

Required Methods

fn next_back(&mut self) -> SearchStep

Unstable

Performs the next search step starting from the back.

  • Returns Match(a, b)`Match(a, b)if` if haystack[a..b]`haystack[a..b]` matches the pattern.
  • Returns Reject(a, b)`Reject(a, b)if` if haystack[a..b]`haystack[a..b]` can not match the pattern, even partially.
  • Returns Done`Done` if every byte of the haystack has been visited

The stream of Match`Matchand` and Reject`Rejectvalues up to a` values up to a Done`Done` will contain index ranges that are adjacent, non-overlapping, covering the whole haystack, and laying on utf8 boundaries.

A Match`Matchresult needs to contain the whole matched pattern, however` result needs to contain the whole matched pattern, however Reject`Reject` results may be split up into arbitrary many adjacent fragments. Both ranges may have zero length.

As an example, the pattern "aaa"`"aaa"and the haystack` and the haystack "cbaaaaab"`"cbaaaaab"might produce the stream` might produce the stream [Reject(7, 8), Match(4, 7), Reject(1, 4), Reject(0, 1)]`[Reject(7, 8), Match(4, 7), Reject(1, 4), Reject(0, 1)]`

Provided Methods

fn next_match_back(&mut self) -> Option<(usize, usize)>

Unstable

Find the next Match`Matchresult. See` result. See next_back()`next_back()`

fn next_reject_back(&mut self) -> Option<(usize, usize)>

Unstable

Find the next Reject`Rejectresult. See` result. See next_back()`next_back()`

Implementors