Implement ExactSizeIterator for Pair iterators
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Signed-off-by: MucTepDayH16 <[email protected]>
Signed-off-by: MucTepDayH16 <[email protected]>
Signed-off-by: MucTepDayH16 <[email protected]>
Signed-off-by: MucTepDayH16 <[email protected]>
tomtau
approved these changes
Apr 17, 2023
pest/src/iterators/flat_pairs.rs
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| fn len(&self) -> usize { | ||
| let mut start = self.start; | ||
| let mut count = 0; | ||
| while start < self.end { | ||
| start += 1; | ||
| while start < self.end && !self.is_start(start) { | ||
| start += 1; | ||
| } | ||
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| count += 1; | ||
| } | ||
| count | ||
| } |
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is it ok for a len to have a linear complexity / a loop there? maybe we can check with this benchmark https://github.com/pest-parser/pest/blob/master/grammars/benches/json.rs#L91 to see if it had any impact? (@huacnlee used to to check that the impact of the line index )
alternatively, perhaps there could be a private field to maintain the length iteratively?
| @@ -92,6 +92,12 @@ impl<'i, R: RuleType> Tokens<'i, R> { | |||
| } | |||
| } | |||
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| impl<'i, R: RuleType> ExactSizeIterator for Tokens<'i, R> { | |||
| fn len(&self) -> usize { | |||
| self.end - self.start | |||
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likely ok, but perhaps good to check / add a test that this works with non-ASCII UTF-8 characters
Signed-off-by: MucTepDayH16 <[email protected]>
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PR adds impl
ExactSizeIteratorandsize_hintaccordingly forPairs,Tokens,FlatPairsandLinesSpan. This can hint rust compiler to allocate proper memory amount while collecting to vector or similar containers