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