1.0.0[−][src]Struct std::cell::Ref
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,
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,
Makes 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
pub fn map_split<U, V, F>(orig: Ref<'b, T>, f: F) -> (Ref<'b, U>, Ref<'b, V>) where
F: FnOnce(&T) -> (&U, &V),
U: ?Sized,
V: ?Sized,
1.35.0[src]
F: FnOnce(&T) -> (&U, &V),
U: ?Sized,
V: ?Sized,
Splits a Ref
into multiple Ref
s 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
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<'_, T> Debug for Ref<'_, T> where
T: Debug + ?Sized,
[src]
T: Debug + ?Sized,
impl<'_, T> Deref for Ref<'_, T> where
T: ?Sized,
[src]
T: ?Sized,
type Target = T
The resulting type after dereferencing.
ⓘImportant traits for &'_ mut Ffn deref(&self) -> &T
[src]
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<'_, T> Display for Ref<'_, T> where
T: Display + ?Sized,
1.20.0[src]
T: Display + ?Sized,
Auto Trait Implementations
impl<'b, T> !UnwindSafe for Ref<'b, T>
impl<'b, T> !RefUnwindSafe for Ref<'b, T>
impl<'b, T: ?Sized> Unpin for Ref<'b, T>
impl<'b, T> !Send for Ref<'b, T>
impl<'b, T> !Sync for Ref<'b, T>
Blanket Implementations
impl<T> From<T> for T
[src]
impl<T, U> TryFrom<U> for T where
U: Into<T>,
[src]
U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> Into<U> for T where
U: From<T>,
[src]
U: From<T>,
impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
[src]
U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
[src]
impl<T> Borrow<T> for T where
T: ?Sized,
[src]
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
[src]
T: ?Sized,
ⓘImportant traits for &'_ mut Ffn borrow_mut(&mut self) -> &mut T
[src]
impl<T> Any for T where
T: 'static + ?Sized,
[src]
T: 'static + ?Sized,
impl<T> ToString for T where
T: Display + ?Sized,
[src]
T: Display + ?Sized,