Struct std::cell::RefMut
[−]
[src]
pub struct RefMut<'b, T> where T: 'b + ?Sized {
_value: &'b mut T,
_borrow: BorrowRefMut<'b>,
}A wrapper type for a mutably borrowed value from a RefCell<T>.
See the module-level documentation for more.
Fields
_value | |
_borrow |
Methods
impl<'b, T> RefMut<'b, T> where T: ?Sized
fn map<U, F>(orig: RefMut<'b, T>, f: F) -> RefMut<'b, U> where U: ?Sized, F: FnOnce(&mut T) -> &mut U
cell_extras): recently added
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'));
fn filter_map<U, F>(orig: RefMut<'b, T>, f: F) -> Option<RefMut<'b, U>> where F: FnOnce(&mut T) -> Option<&mut U>, U: ?Sized
cell_extras): recently added
Make a new RefMut for an optional 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::filter_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(Ok(5)); { let b1: RefMut<Result<u32, ()>> = c.borrow_mut(); let mut b2: RefMut<u32> = RefMut::filter_map(b1, |o| { o.as_mut().ok() }).unwrap(); assert_eq!(*b2, 5); *b2 = 42; } assert_eq!(*c.borrow(), Ok(42));