1.0.0[−][src]Struct core::cell::RefMut
A wrapper type for a mutably borrowed value from a RefCell<T>
.
See the module-level documentation for more.
Methods
impl<'b, T: ?Sized> RefMut<'b, T>
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impl<'b, T: ?Sized> RefMut<'b, T>
pub fn map<U: ?Sized, F>(orig: RefMut<'b, T>, f: F) -> RefMut<'b, U> where
F: FnOnce(&mut T) -> &mut U,
1.8.0[src]
pub fn map<U: ?Sized, F>(orig: RefMut<'b, T>, f: F) -> RefMut<'b, U> where
F: FnOnce(&mut T) -> &mut U,
Make a new RefMut
for a component of the borrowed data, e.g. an enum
variant.
The RefCell
is already mutably borrowed, so this cannot fail.
This is an associated function that needs to be used as
RefMut::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, RefMut}; let c = RefCell::new((5, 'b')); { let b1: RefMut<(u32, char)> = c.borrow_mut(); let mut b2: RefMut<u32> = RefMut::map(b1, |t| &mut t.0); assert_eq!(*b2, 5); *b2 = 42; } assert_eq!(*c.borrow(), (42, 'b'));Run
pub fn map_split<U: ?Sized, V: ?Sized, F>(
orig: RefMut<'b, T>,
f: F
) -> (RefMut<'b, U>, RefMut<'b, V>) where
F: FnOnce(&mut T) -> (&mut U, &mut V),
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pub fn map_split<U: ?Sized, V: ?Sized, F>(
orig: RefMut<'b, T>,
f: F
) -> (RefMut<'b, U>, RefMut<'b, V>) where
F: FnOnce(&mut T) -> (&mut U, &mut V),
Split a RefMut
into multiple RefMut
s for different components of the
borrowed data.
The underlying RefCell
will remain mutably borrowed until both
returned RefMut
s go out of scope.
The RefCell
is already mutably borrowed, so this cannot fail.
This is an associated function that needs to be used as
RefMut::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::{RefCell, RefMut}; let cell = RefCell::new([1, 2, 3, 4]); let borrow = cell.borrow_mut(); let (mut begin, mut end) = RefMut::map_split(borrow, |slice| slice.split_at_mut(2)); assert_eq!(*begin, [1, 2]); assert_eq!(*end, [3, 4]); begin.copy_from_slice(&[4, 3]); end.copy_from_slice(&[2, 1]);Run
Trait Implementations
impl<T: ?Sized, '_> Deref for RefMut<'_, T>
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impl<T: ?Sized, '_> Deref for RefMut<'_, T>
type Target = T
The resulting type after dereferencing.
fn deref(&self) -> &T
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fn deref(&self) -> &T
Dereferences the value.
impl<T: ?Sized, '_> DerefMut for RefMut<'_, T>
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impl<T: ?Sized, '_> DerefMut for RefMut<'_, T>
impl<'b, T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<RefMut<'b, U>> for RefMut<'b, T>
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impl<'b, T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<RefMut<'b, U>> for RefMut<'b, T>
impl<T: ?Sized + Debug, '_> Debug for RefMut<'_, T>
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impl<T: ?Sized + Debug, '_> Debug for RefMut<'_, T>
fn fmt(&self, f: &mut Formatter) -> Result
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fn fmt(&self, f: &mut Formatter) -> Result
Formats the value using the given formatter. Read more
impl<T: ?Sized + Display, '_> Display for RefMut<'_, T>
1.20.0[src]
impl<T: ?Sized + Display, '_> Display for RefMut<'_, T>
Auto Trait Implementations
Blanket Implementations
impl<T, U> Into for T where
U: From<T>,
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impl<T, U> Into for T where
U: From<T>,
impl<T> From for T
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impl<T> From for T
impl<T, U> TryInto for T where
U: TryFrom<T>,
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impl<T, U> TryInto for T where
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>
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fn try_into(Self) -> Result<U, <U as TryFrom<T>>::Error>
Performs the conversion.
impl<T, U> TryFrom for T where
T: From<U>,
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impl<T, U> TryFrom for T where
T: From<U>,
type Error = !
The type returned in the event of a conversion error.
fn try_from(U) -> Result<T, <T as TryFrom<U>>::Error>
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fn try_from(U) -> Result<T, <T as TryFrom<U>>::Error>
Performs the conversion.
impl<T> Borrow for T where
T: ?Sized,
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impl<T> Borrow for T where
T: ?Sized,
impl<T> BorrowMut for T where
T: ?Sized,
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impl<T> BorrowMut for T where
T: ?Sized,
fn borrow_mut(&mut Self) -> &mut T
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fn borrow_mut(&mut Self) -> &mut T
Mutably borrows from an owned value. Read more
impl<T> Any for T where
T: 'static + ?Sized,
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impl<T> Any for T where
T: 'static + ?Sized,
fn get_type_id(&Self) -> TypeId
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fn get_type_id(&Self) -> TypeId
🔬 This is a nightly-only experimental API. (get_type_id
#27745)
this method will likely be replaced by an associated static
Gets the TypeId
of self
. Read more