std::cell::Ref
Struct std::cell::Ref
pub struct Ref<'b, T> where T: 'b + ?Sized, { /* fields omitted */ }
Wraps a borrowed reference to a value in a RefCell box. A wrapper type for an immutably borrowed value from a RefCell<T>.
See the module-level documentation for more-
Methods
impl<'b, T> Ref<'b, T> where
T: ?Sized,
[src]
T: ?Sized,
fn clone(orig: &Ref<'b, T>) -> Ref<'b, T>1.15.0
Copies a Ref.
The RefCell is already immutably borrowed, so this cannot fail.
This is an associated function that needs to be used as Ref::clone(...). A Clone implementation or a method would interfere with the widespread use of r.borrow().clone() to clone the contents of a RefCell.
fn map<U, F>(orig: Ref<'b, T>, f: F) -> Ref<'b, U> where
F: FnOnce(&T) -> &U,
U: ?Sized, 1.8.0
F: FnOnce(&T) -> &U,
U: ?Sized,
Make a new Ref for a component of the borrowed data.
The RefCell is already immutably borrowed, so this cannot fail.
This is an associated function that needs to be used as Ref::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, Ref};
let c = RefCell::new((5, 'b'));
let b1: Ref<(u32, char)> = c.borrow();
let b2: Ref<u32> = Ref::map(b1, |t| &t.0);
assert_eq!(*b2, 5) Trait Implementations
impl<'b, T, U> CoerceUnsized<Ref<'b, U>> for Ref<'b, T> where
T: Unsize<U> + ?Sized,
U: ?Sized,
[src]
T: Unsize<U> + ?Sized,
U: ?Sized,
impl<'b, T> Debug for Ref<'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 Ref<'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.Ref.html
