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Reduce genericity in TakeWhile

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This commit is contained in:
Josh Stone 2019-07-11 18:09:27 -07:00
parent 5902522c04
commit 2d7fc4dd49
1 changed files with 23 additions and 16 deletions
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39
src/libcore/iter/adapters/mod.rs
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@ -1495,14 +1495,13 @@ impl<I: Iterator, P> Iterator for TakeWhile<I, P>
if self.flag {
None
} else {
self.iter.next().and_then(|x| {
if (self.predicate)(&x) {
Some(x)
} else {
self.flag = true;
None
}
})
let x = self.iter.next()?;
if (self.predicate)(&x) {
Some(x)
} else {
self.flag = true;
None
}
}
}
@ -1517,22 +1516,30 @@ impl<I: Iterator, P> Iterator for TakeWhile<I, P>
}
#[inline]
fn try_fold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
{
if self.flag {
Try::from_ok(init)
} else {
let flag = &mut self.flag;
let p = &mut self.predicate;
self.iter.try_fold(init, move |acc, x|{
fn check<'a, T, Acc, R: Try<Ok = Acc>>(
flag: &'a mut bool,
p: &'a mut impl FnMut(&T) -> bool,
mut fold: impl FnMut(Acc, T) -> R + 'a,
) -> impl FnMut(Acc, T) -> LoopState<Acc, R> + 'a {
move |acc, x| {
if p(&x) {
LoopState::from_try(fold(acc, x))
} else {
*flag = true;
LoopState::Break(Try::from_ok(acc))
}
}).into_try()
}
}
if self.flag {
Try::from_ok(init)
} else {
let flag = &mut self.flag;
let p = &mut self.predicate;
self.iter.try_fold(init, check(flag, p, fold)).into_try()
}
}
}