Struct std::cell::RefMut1.0.0 [] [src]

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.


impl<'b, T> RefMut<'b, T> where T: ?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.


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'));Run

Trait Implementations

impl<'b, T> Deref for RefMut<'b, T> where T: ?Sized

The resulting type after dereferencing

The method called to dereference a value

impl<'b, T> Debug for RefMut<'b, T> where T: Debug + ?Sized

Formats the value using the given formatter.

impl<'b, T> DerefMut for RefMut<'b, T> where T: ?Sized

The method called to mutably dereference a value

impl<'b, T, U> CoerceUnsized<RefMut<'b, U>> for RefMut<'b, T> where T: Unsize<U> + ?Sized, U: ?Sized