Struct std::cell::Ref1.0.0[][src]

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]

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.

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.

Examples

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)Run

🔬 This is a nightly-only experimental API. (refcell_map_split #51476)

Split a Ref into multiple Refs for different components 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_split(...). A method would interfere with methods of the same name on the contents of a RefCell used through Deref.

Examples

#![feature(refcell_map_split)]
use std::cell::{Ref, RefCell};

let cell = RefCell::new([1, 2, 3, 4]);
let borrow = cell.borrow();
let (begin, end) = Ref::map_split(borrow, |slice| slice.split_at(2));
assert_eq!(*begin, [1, 2]);
assert_eq!(*end, [3, 4]);Run

Trait Implementations

impl<'b, T> Debug for Ref<'b, T> where
    T: Debug + ?Sized
[src]

Formats the value using the given formatter. Read more

impl<'b, T, U> CoerceUnsized<Ref<'b, U>> for Ref<'b, T> where
    T: Unsize<U> + ?Sized,
    U: ?Sized
[src]

impl<'b, T> Deref for Ref<'b, T> where
    T: ?Sized
[src]

The resulting type after dereferencing.

Important traits for &'a mut I

Dereferences the value.

impl<'a, T> Display for Ref<'a, T> where
    T: Display + ?Sized
1.20.0
[src]

Formats the value using the given formatter. Read more

Auto Trait Implementations

impl<'b, T> !Send for Ref<'b, T>

impl<'b, T> !Sync for Ref<'b, T>