1.0.0[−][src]Struct std::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> RefMut<'b, T> where
T: ?Sized,
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T: ?Sized,
pub fn map<U, F>(orig: RefMut<'b, T>, f: F) -> RefMut<'b, U> where
F: FnOnce(&mut T) -> &mut U,
U: ?Sized,
1.8.0[src]
F: FnOnce(&mut T) -> &mut U,
U: ?Sized,
Makes 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, V, F>(
orig: RefMut<'b, T>,
f: F
) -> (RefMut<'b, U>, RefMut<'b, V>) where
F: FnOnce(&mut T) -> (&mut U, &mut V),
U: ?Sized,
V: ?Sized,
1.35.0[src]
orig: RefMut<'b, T>,
f: F
) -> (RefMut<'b, U>, RefMut<'b, V>) where
F: FnOnce(&mut T) -> (&mut U, &mut V),
U: ?Sized,
V: ?Sized,
Splits 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
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> DerefMut for RefMut<'_, T> where
T: ?Sized,
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T: ?Sized,
impl<'_, T> Deref for RefMut<'_, T> where
T: ?Sized,
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T: ?Sized,
type Target = T
The resulting type after dereferencing.
ⓘImportant traits for &'_ mut Ffn deref(&self) -> &T
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impl<'_, T> Debug for RefMut<'_, T> where
T: Debug + ?Sized,
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T: Debug + ?Sized,
impl<'b, T, U> CoerceUnsized<RefMut<'b, U>> for RefMut<'b, T> where
T: Unsize<U> + ?Sized,
U: ?Sized,
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T: Unsize<U> + ?Sized,
U: ?Sized,
impl<'_, T> Display for RefMut<'_, T> where
T: Display + ?Sized,
1.20.0[src]
T: Display + ?Sized,
Auto Trait Implementations
Blanket Implementations
impl<T, U> TryFrom<U> for T where
U: Into<T>,
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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>,
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U: From<T>,
impl<T> From<T> for T
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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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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impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
ⓘImportant traits for &'_ mut Ffn borrow_mut(&mut self) -> &mut T
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impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> ToString for T where
T: Display + ?Sized,
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T: Display + ?Sized,