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// Copyright 2012-2013 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.
//! The `Clone` trait for types that cannot be 'implicitly copied'
//!
//! In Rust, some simple types are "implicitly copyable" and when you
//! assign them or pass them as arguments, the receiver will get a copy,
//! leaving the original value in place. These types do not require
//! allocation to copy and do not have finalizers (i.e. they do not
//! contain owned boxes or implement `Drop`), so the compiler considers
//! them cheap and safe to copy. For other types copies must be made
//! explicitly, by convention implementing the `Clone` trait and calling
//! the `clone` method.
#![unstable]
use kinds::Sized;
/// A common trait for cloning an object.
pub trait Clone {
/// Returns a copy of the value.
fn clone(&self) -> Self;
/// Perform copy-assignment from `source`.
///
/// `a.clone_from(&b)` is equivalent to `a = b.clone()` in functionality,
/// but can be overridden to reuse the resources of `a` to avoid unnecessary
/// allocations.
#[inline(always)]
#[experimental = "this function is mostly unused"]
fn clone_from(&mut self, source: &Self) {
*self = source.clone()
}
}
impl<'a, Sized? T> Clone for &'a T {
/// Return a shallow copy of the reference.
#[inline]
fn clone(&self) -> &'a T { *self }
}
macro_rules! clone_impl(
($t:ty) => {
impl Clone for $t {
/// Return a deep copy of the value.
#[inline]
fn clone(&self) -> $t { *self }
}
}
)
clone_impl!(int)
clone_impl!(i8)
clone_impl!(i16)
clone_impl!(i32)
clone_impl!(i64)
clone_impl!(uint)
clone_impl!(u8)
clone_impl!(u16)
clone_impl!(u32)
clone_impl!(u64)
clone_impl!(f32)
clone_impl!(f64)
clone_impl!(())
clone_impl!(bool)
clone_impl!(char)
macro_rules! extern_fn_clone(
($($A:ident),*) => (
#[experimental = "this may not be sufficient for fns with region parameters"]
impl<$($A,)* ReturnType> Clone for extern "Rust" fn($($A),*) -> ReturnType {
/// Return a copy of a function pointer
#[inline]
fn clone(&self) -> extern "Rust" fn($($A),*) -> ReturnType { *self }
}
)
)
extern_fn_clone!()
extern_fn_clone!(A)
extern_fn_clone!(A, B)
extern_fn_clone!(A, B, C)
extern_fn_clone!(A, B, C, D)
extern_fn_clone!(A, B, C, D, E)
extern_fn_clone!(A, B, C, D, E, F)
extern_fn_clone!(A, B, C, D, E, F, G)
extern_fn_clone!(A, B, C, D, E, F, G, H)
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