59 lines
1.7 KiB
Rust
59 lines
1.7 KiB
Rust
// Copyright 2012-4 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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// Tests that type assignability is used to search for instances when
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// making method calls, but only if there aren't any matches without
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// it.
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// pretty-expanded FIXME #23616
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#![feature(unboxed_closures)]
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trait iterable<A> {
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fn iterate<F>(&self, blk: F) -> bool where F: FnMut(&A) -> bool;
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}
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impl<'a,A> iterable<A> for &'a [A] {
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fn iterate<F>(&self, f: F) -> bool where F: FnMut(&A) -> bool {
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self.iter().all(f)
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}
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}
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impl<A> iterable<A> for Vec<A> {
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fn iterate<F>(&self, f: F) -> bool where F: FnMut(&A) -> bool {
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self.iter().all(f)
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}
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}
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fn length<A, T: iterable<A>>(x: T) -> usize {
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let mut len = 0;
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x.iterate(|_y| {
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len += 1;
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true
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});
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return len;
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}
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pub fn main() {
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let x: Vec<isize> = vec!(0,1,2,3);
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// Call a method
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x.iterate(|y| { assert!(x[*y as usize] == *y); true });
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// Call a parameterized function
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assert_eq!(length(x.clone()), x.len());
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// Call a parameterized function, with type arguments that require
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// a borrow
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assert_eq!(length::<isize, &[isize]>(&*x), x.len());
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// Now try it with a type that *needs* to be borrowed
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let z = [0,1,2,3];
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// Call a parameterized function
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assert_eq!(length::<isize, &[isize]>(&z), z.len());
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}
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