Struct std::cell::Ref 1.0.0
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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]
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: ?Sized1.8.0
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)Run
Trait Implementations
impl<'b, T, U> CoerceUnsized<Ref<'b, U>> for Ref<'b, T> where T: Unsize<U> + ?Sized,
U: ?Sized[src]
U: ?Sized