impl Match

fn new<S: Into<Span>>(pattern: PatternID, span: S) -> Match

Create a new match from a pattern ID and a span.

This constructor is generic over how a span is provided. While a Span may be given directly, one may also provide a std::ops::Range<usize>.

Panics

This panics if end < start.

Example

This shows how to create a match for the first pattern in a regex object using convenient range syntax.

use regex_automata::{Match, PatternID};

let m = Match::new(PatternID::ZERO, 5..10);
assert_eq!(0, m.pattern().as_usize());
assert_eq!(5, m.start());
assert_eq!(10, m.end());

fn must<S: Into<Span>>(pattern: usize, span: S) -> Match

Create a new match from a pattern ID and a byte offset span.

This constructor is generic over how a span is provided. While a Span may be given directly, one may also provide a std::ops::Range<usize>.

This is like Match::new, but accepts a usize instead of a PatternID. This panics if the given usize is not representable as a PatternID.

Panics

This panics if end < start or if pattern > PatternID::MAX.

Example

This shows how to create a match for the third pattern in a regex object using convenient range syntax.

use regex_automata::Match;

let m = Match::must(3, 5..10);
assert_eq!(3, m.pattern().as_usize());
assert_eq!(5, m.start());
assert_eq!(10, m.end());

fn pattern(&self) -> PatternID

Returns the ID of the pattern that matched.

The ID of a pattern is derived from the position in which it was originally inserted into the corresponding regex engine. The first pattern has identifier 0, and each subsequent pattern is 1, 2 and so on.

fn start(&self) -> usize

The starting position of the match.

This is a convenience routine for Match::span().start.

fn end(&self) -> usize

The ending position of the match.

This is a convenience routine for Match::span().end.

fn range(&self) -> Range<usize>

Returns the match span as a range.

This is a convenience routine for Match::span().range().

fn span(&self) -> Span

Returns the span for this match.

fn is_empty(&self) -> bool

Returns true when the span in this match is empty.

An empty match can only be returned when the regex itself can match the empty string.

fn len(&self) -> usize

Returns the length of this match.

This returns 0 in precisely the cases that is_empty returns true.