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// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
fn iterate<T, F>(initial: T, f: F) -> Iterate<T, F> {
Iterate {
state: initial,
f: f,
}
}
pub struct Iterate<T, F> {
state: T,
f: F
}
impl<T: Clone, F> Iterator for Iterate<T, F> where F: Fn(&T) -> T {
type Item = T;
#[inline]
fn next(&mut self) -> Option<Self::Item> {
self.state = (self.f)(&self.state);
Some(self.state.clone())
}
#[inline]
fn size_hint(&self) -> (usize, Option<usize>) { (std::usize::MAX, None) }
}
fn main() {
let a = iterate(0, |x| x+1);
println!("{:?}", a.iter().take(10).collect::<Vec<usize>>());
//~^ ERROR no method named `iter` found for type `Iterate<{integer}
}
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