Trait std::str::pattern::Searcher [−] [src]

pub unsafe trait Searcher<'a> {
    fn haystack(&self) -> &'a str;
    fn next(&mut self) -> SearchStep;

    fn next_match(&mut self) -> Option<(usize, usize)> { ... }
    fn next_reject(&mut self) -> Option<(usize, usize)> { ... }
}
Unstable (pattern #27721)

: API not fully fleshed out and ready to be stabilized

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

fn haystack(&self) -> &'a str

Unstable (pattern #27721)

: API not fully fleshed out and ready to be stabilized

Getter for the underlaying string to be searched in

Will always return the same &str

fn next(&mut self) -> SearchStep

Unstable (pattern #27721)

: API not fully fleshed out and ready to be stabilized

Performs the next search step starting from the front.

  • Returns Match(a, b) if haystack[a..b] matches the pattern.
  • Returns Reject(a, b) if haystack[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.

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

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

Unstable (pattern #27721)

: API not fully fleshed out and ready to be stabilized

Find the next Match result. See next()

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

Unstable (pattern #27721)

: API not fully fleshed out and ready to be stabilized

Find the next Reject result. See next()

Implementors