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,
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T: ?Sized,
pub fn clone(orig: &Ref<'b, T>) -> Ref<'b, T>
1.15.0[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
.
pub fn map<U, F>(orig: Ref<'b, T>, f: F) -> Ref<'b, U> where
F: FnOnce(&T) -> &U,
U: ?Sized,
1.8.0[src]
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
.
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
Trait Implementations
impl<'b, T> Debug for Ref<'b, T> where
T: Debug + ?Sized,
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T: Debug + ?Sized,
fn fmt(&self, f: &mut Formatter) -> Result<(), Error>
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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,
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T: Unsize<U> + ?Sized,
U: ?Sized,
impl<'b, T> Deref for Ref<'b, T> where
T: ?Sized,
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T: ?Sized,
type Target = T
The resulting type after dereferencing.
ⓘImportant traits for &'a mut Ifn deref(&self) -> &T
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Dereferences the value.
impl<'a, T> Display for Ref<'a, T> where
T: Display + ?Sized,
1.20.0[src]
T: Display + ?Sized,