std::cell::RefMut
Struct std::cell::RefMut
pub struct RefMut<'b, T> where T: 'b + ?Sized, { /* fields omitted */ }
A wrapper type for a mutably borrowed value from a RefCell<T>.
See the module-level documentation for more-
Methods
impl<'b, T> RefMut<'b, T> where
T: ?Sized,
[src]
T: ?Sized,
fn map<U, F>(orig: RefMut<'b, T>, f: F) -> RefMut<'b, U> where
F: FnOnce(&mut T) -> &mut U,
U: ?Sized, 1.8.0
F: FnOnce(&mut T) -> &mut U,
U: ?Sized,
Make a new RefMut for a component of the borrowed data, e.g. an enum variant.
The RefCell is already mutably borrowed, so this cannot fail.
This is an associated function that needs to be used as RefMut::map(...). A method would interfere with methods of the same name on the contents of a RefCell used through Deref.
Example
use std::cell::{RefCell, RefMut};
let c = RefCell::new((5, 'b'));
{
let b1: RefMut<(u32, char)> = c.borrow_mut();
let mut b2: RefMut<u32> = RefMut::map(b1, |t| &mut t.0);
assert_eq!(*b2, 5);
*b2 = 42;
}
assert_eq!(*c.borrow(), (42, 'b')); Trait Implementations
impl<'b, T, U> CoerceUnsized<RefMut<'b, U>> for RefMut<'b, T> where
T: Unsize<U> + ?Sized,
U: ?Sized,
[src]
T: Unsize<U> + ?Sized,
U: ?Sized,
impl<'b, T> DerefMut for RefMut<'b, T> where
T: ?Sized,
[src]
T: ?Sized,
fn deref_mut(&mut self) -> &mut T
The method called to mutably dereference a value
impl<'b, T> Debug for RefMut<'b, T> where
T: Debug + ?Sized,
[src]
T: Debug + ?Sized,
fn fmt(&self, f: &mut Formatter) -> Result<(), Error>
Formats the value using the given formatter.
impl<'b, T> Deref for RefMut<'b, T> where
T: ?Sized,
[src]
T: ?Sized,
type Target = T
The resulting type after dereferencing
fn deref(&self) -> &T
The method called to dereference a value
© 2010 The Rust Project Developers
Licensed under the Apache License, Version 2.0 or the MIT license, at your option.
https://doc.rust-lang.org/std/cell/struct.RefMut.html
