78 lines
1.7 KiB
Rust
78 lines
1.7 KiB
Rust
// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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#![feature(generators, generator_trait)]
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use std::ops::{GeneratorState, Generator};
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fn finish<T>(mut amt: usize, mut t: T) -> T::Return
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where T: Generator<Yield = usize>
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{
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loop {
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match unsafe { t.resume() } {
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GeneratorState::Yielded(y) => amt -= y,
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GeneratorState::Complete(ret) => {
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assert_eq!(amt, 0);
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return ret
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}
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}
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}
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}
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fn main() {
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finish(1, || yield 1);
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finish(3, || {
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let mut x = 0;
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yield 1;
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x += 1;
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yield 1;
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x += 1;
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yield 1;
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assert_eq!(x, 2);
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});
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finish(7*8/2, || {
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for i in 0..8 {
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yield i;
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}
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});
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finish(1, || {
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if true {
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yield 1;
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} else {
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}
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});
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finish(1, || {
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if false {
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} else {
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yield 1;
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}
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});
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finish(2, || {
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if { yield 1; false } {
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yield 1;
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panic!()
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}
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yield 1;
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});
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// also test a self-referential generator
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assert_eq!(
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finish(5, || {
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let mut x = Box::new(5);
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let y = &mut *x;
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*y = 5;
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yield *y;
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*y = 10;
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*x
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}),
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10
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);
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}
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