diff options
| -rw-r--r-- | src/libcore/mem/mod.rs | 28 |
1 files changed, 20 insertions, 8 deletions
diff --git a/src/libcore/mem/mod.rs b/src/libcore/mem/mod.rs index e110e93a954..b31522db474 100644 --- a/src/libcore/mem/mod.rs +++ b/src/libcore/mem/mod.rs @@ -552,6 +552,12 @@ pub fn swap<T>(x: &mut T, y: &mut T) { /// mem::take(&mut self.buf) /// } /// } +/// +/// let mut buffer = Buffer { buf: vec![0, 1] }; +/// assert_eq!(buffer.buf.len(), 2); +/// +/// assert_eq!(buffer.get_and_reset(), vec![0, 1]); +/// assert_eq!(buffer.buf.len(), 0); /// ``` /// /// [`Clone`]: ../../std/clone/trait.Clone.html @@ -586,17 +592,17 @@ pub fn take<T: Default>(dest: &mut T) -> T { /// struct Buffer<T> { buf: Vec<T> } /// /// impl<T> Buffer<T> { -/// fn get_and_reset(&mut self) -> Vec<T> { +/// fn replace_index(&mut self, i: usize, v: T) -> T { /// // error: cannot move out of dereference of `&mut`-pointer -/// let buf = self.buf; -/// self.buf = Vec::new(); -/// buf +/// let t = self.buf[i]; +/// self.buf[i] = v; +/// t /// } /// } /// ``` /// -/// Note that `T` does not necessarily implement [`Clone`], so it can't even clone and reset -/// `self.buf`. But `replace` can be used to disassociate the original value of `self.buf` from +/// Note that `T` does not necessarily implement [`Clone`], so we can't even clone `self.buf[i]` to +/// avoid the move. But `replace` can be used to disassociate the original value at that index from /// `self`, allowing it to be returned: /// /// ``` @@ -605,10 +611,16 @@ pub fn take<T: Default>(dest: &mut T) -> T { /// /// # struct Buffer<T> { buf: Vec<T> } /// impl<T> Buffer<T> { -/// fn get_and_reset(&mut self) -> Vec<T> { -/// mem::replace(&mut self.buf, Vec::new()) +/// fn replace_index(&mut self, i: usize, v: T) -> T { +/// mem::replace(&mut self.buf[i], v) /// } /// } +/// +/// let mut buffer = Buffer { buf: vec![0, 1] }; +/// assert_eq!(buffer.buf[0], 0); +/// +/// assert_eq!(buffer.replace_index(0, 2), 0); +/// assert_eq!(buffer.buf[0], 2); /// ``` /// /// [`Clone`]: ../../std/clone/trait.Clone.html |