39 lines
1.1 KiB
Rust
39 lines
1.1 KiB
Rust
// Copyright 2013 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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//! Traits for generic collections
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/// A trait to represent the abstract idea of a container. The only concrete
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/// knowledge known is the number of elements contained within.
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pub trait Collection {
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/// Return the number of elements in the container
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///
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/// # Example
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///
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/// ```
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/// let a = [1i, 2, 3];
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/// assert_eq!(a.len(), 3);
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/// ```
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fn len(&self) -> uint;
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/// Return true if the container contains no elements
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///
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/// # Example
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///
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/// ```
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/// let s = String::new();
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/// assert!(s.is_empty());
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/// ```
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#[inline]
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fn is_empty(&self) -> bool {
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self.len() == 0
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}
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}
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