46 lines
1.1 KiB
Rust
46 lines
1.1 KiB
Rust
// Copyright 2012 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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// There is some other borrowck bug, so we make the stuff not mut.
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use std::ops::Add;
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trait Positioned<S> {
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fn SetX(&mut self, _: S);
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fn X(&self) -> S;
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}
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trait Movable<S: Add<Output=S>>: Positioned<S> {
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fn translate(&mut self, dx: S) {
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let x = self.X() + dx;
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self.SetX(x);
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}
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}
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struct Point<S> { x: S, y: S }
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impl<S: Clone> Positioned<S> for Point<S> {
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fn SetX(&mut self, x: S) {
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self.x = x;
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}
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fn X(&self) -> S {
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self.x.clone()
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}
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}
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impl<S: Clone + Add<Output=S>> Movable<S> for Point<S> {}
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pub fn main() {
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let mut p = Point{ x: 1, y: 2};
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p.translate(3);
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assert_eq!(p.X(), 4);
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}
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