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56 lines
1.2 KiB
Rust
56 lines
1.2 KiB
Rust
// run-pass
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#![allow(unused_must_use)]
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#![allow(dead_code)]
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// pretty-expanded FIXME #23616
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trait Matcher {
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fn next_match(&mut self) -> Option<(usize, usize)>;
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}
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struct CharPredMatcher<'a, 'b> {
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str: &'a str,
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pred: Box<dyn FnMut(char) -> bool + 'b>,
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}
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impl<'a, 'b> Matcher for CharPredMatcher<'a, 'b> {
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fn next_match(&mut self) -> Option<(usize, usize)> {
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None
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}
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}
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trait IntoMatcher<'a, T> {
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fn into_matcher(self, _: &'a str) -> T;
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}
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impl<'a, 'b, F> IntoMatcher<'a, CharPredMatcher<'a, 'b>> for F where F: FnMut(char) -> bool + 'b {
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fn into_matcher(self, s: &'a str) -> CharPredMatcher<'a, 'b> {
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CharPredMatcher {
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str: s,
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pred: Box::new(self),
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}
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}
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}
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struct MatchIndices<M> {
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matcher: M
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}
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impl<M: Matcher> Iterator for MatchIndices<M> {
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type Item = (usize, usize);
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fn next(&mut self) -> Option<(usize, usize)> {
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self.matcher.next_match()
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}
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}
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fn match_indices<'a, M, T: IntoMatcher<'a, M>>(s: &'a str, from: T) -> MatchIndices<M> {
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let string_matcher = from.into_matcher(s);
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MatchIndices { matcher: string_matcher }
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}
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fn main() {
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let s = "abcbdef";
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match_indices(s, |c: char| c == 'b')
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.collect::<Vec<_>>();
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}
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