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30 lines
646 B
Rust
30 lines
646 B
Rust
fn iterate<T, F>(initial: T, f: F) -> Iterate<T, F> {
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Iterate {
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state: initial,
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f: f,
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}
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}
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pub struct Iterate<T, F> {
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state: T,
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f: F
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}
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impl<T: Clone, F> Iterator for Iterate<T, F> where F: Fn(&T) -> T {
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type Item = T;
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#[inline]
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fn next(&mut self) -> Option<Self::Item> {
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self.state = (self.f)(&self.state);
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Some(self.state.clone())
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}
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#[inline]
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fn size_hint(&self) -> (usize, Option<usize>) { (usize::MAX, None) }
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}
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fn main() {
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let a = iterate(0, |x| x+1);
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println!("{:?}", a.iter().take(10).collect::<Vec<usize>>());
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//~^ ERROR no method named `iter` found
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}
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