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Implement Option::replace in the core library #52003

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Merged
bors merged 3 commits into from
Jul 13, 2018
Merged

Implement Option::replace in the core library #52003

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6035534
Implement `Option::replace` in the core library
Kerollmops Jul 4, 2018
af87a35
Add a basic test to `Option::replace`
Jul 9, 2018
c8f0e6f
Fix the documentation of `Option::replace`
Jul 9, 2018
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27 changes: 27 additions & 0 deletions src/libcore/option.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -845,6 +845,33 @@ impl<T> Option<T> {
pub fn take(&mut self) -> Option<T> {
mem::replace(self, None)
}

/// Replaces the actual value in the option by the value given in parameter,
/// returning the old value if present,
/// leaving a `Some` in its place without deinitializing either one.
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@Kerollmops Kerollmops Jul 9, 2018

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Ooops.. And I forgot to add [] around Some.

///
/// [`Some`]: #variant.Some
///
/// # Examples
///
/// ```
/// #![feature(option_replace)]
///
/// let mut x = Some(2);
/// let old = x.replace(5);
/// assert_eq!(x, Some(5));
/// assert_eq!(old, Some(2));
///
/// let mut x = None;
/// let old = x.replace(3);
/// assert_eq!(x, Some(3));
/// assert_eq!(old, None);
/// ```
#[inline]
#[unstable(feature = "option_replace", issue = "51998")]
pub fn replace(&mut self, value: T) -> Option<T> {
mem::replace(self, Some(value))
}
}

impl<'a, T: Clone> Option<&'a T> {
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