Struct enso_prelude::RefMut 1.0.0[−][src]
pub struct RefMut<'b, T> where
T: 'b + ?Sized, { /* fields omitted */ }
Expand description
A wrapper type for a mutably borrowed value from a RefCell<T>
.
See the module-level documentation for more.
Implementations
impl<'b, T> RefMut<'b, T> where
T: ?Sized,
[src]
impl<'b, T> RefMut<'b, T> where
T: ?Sized,
[src]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]
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]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'));
pub fn filter_map<U, F>(
orig: RefMut<'b, T>,
f: F
) -> Result<RefMut<'b, U>, RefMut<'b, T>> where
F: FnOnce(&mut T) -> Option<&mut U>,
U: ?Sized,
[src]
🔬 This is a nightly-only experimental API. (cell_filter_map
)
recently added
pub fn filter_map<U, F>(
orig: RefMut<'b, T>,
f: F
) -> Result<RefMut<'b, U>, RefMut<'b, T>> where
F: FnOnce(&mut T) -> Option<&mut U>,
U: ?Sized,
[src]🔬 This is a nightly-only experimental API. (cell_filter_map
)
recently added
Makes a new RefMut
for an optional component of the borrowed data. The
original guard is returned as an Err(..)
if the closure returns
None
.
The RefCell
is already mutably borrowed, so this cannot fail.
This is an associated function that needs to be used as
RefMut::filter_map(...)
. A method would interfere with methods of the
same name on the contents of a RefCell
used through Deref
.
Examples
#![feature(cell_filter_map)] use std::cell::{RefCell, RefMut}; let c = RefCell::new(vec![1, 2, 3]); { let b1: RefMut<Vec<u32>> = c.borrow_mut(); let mut b2: Result<RefMut<u32>, _> = RefMut::filter_map(b1, |v| v.get_mut(1)); if let Ok(mut b2) = b2 { *b2 += 2; } } assert_eq!(*c.borrow(), vec![1, 4, 3]);
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),
V: ?Sized,
U: ?Sized,
1.35.0[src]
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),
V: ?Sized,
U: ?Sized,
1.35.0[src]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]);
pub fn leak(orig: RefMut<'b, T>) -> &'b mut T
[src]
🔬 This is a nightly-only experimental API. (cell_leak
)
pub fn leak(orig: RefMut<'b, T>) -> &'b mut T
[src]cell_leak
)Convert into a mutable reference to the underlying data.
The underlying RefCell
can not be borrowed from again and will always appear already
mutably borrowed, making the returned reference the only to the interior.
This is an associated function that needs to be used as
RefMut::leak(...)
. A method would interfere with methods of the
same name on the contents of a RefCell
used through Deref
.
Examples
#![feature(cell_leak)] use std::cell::{RefCell, RefMut}; let cell = RefCell::new(0); let value = RefMut::leak(cell.borrow_mut()); assert_eq!(*value, 0); *value = 1; assert!(cell.try_borrow_mut().is_err());
Trait Implementations
impl<'b, T, U> CoerceUnsized<RefMut<'b, U>> for RefMut<'b, T> where
T: Unsize<U> + ?Sized,
U: ?Sized,
[src]
T: Unsize<U> + ?Sized,
U: ?Sized,
Auto Trait Implementations
impl<'b, T> !RefUnwindSafe for RefMut<'b, T>
impl<'b, T> !Send for RefMut<'b, T>
impl<'b, T> !Sync for RefMut<'b, T>
impl<'b, T: ?Sized> Unpin for RefMut<'b, T>
impl<'b, T> !UnwindSafe for RefMut<'b, T>
Blanket Implementations
impl<T> BorrowMut<T> for T where
T: ?Sized,
[src]
impl<T> BorrowMut<T> for T where
T: ?Sized,
[src]pub fn borrow_mut(&mut self) -> &mut T
[src]
pub fn borrow_mut(&mut self) -> &mut T
[src]Mutably borrows from an owned value. Read more
impl<T> Same<T> for T
impl<T> Same<T> for T
type Output = T
type Output = T
Should always be Self
impl<SS, SP> SupersetOf<SS> for SP where
SS: SubsetOf<SP>,
impl<SS, SP> SupersetOf<SS> for SP where
SS: SubsetOf<SP>,
pub fn to_subset(&self) -> Option<SS>
pub fn to_subset(&self) -> Option<SS>
The inverse inclusion map: attempts to construct self
from the equivalent element of its
superset. Read more
pub fn is_in_subset(&self) -> bool
pub fn is_in_subset(&self) -> bool
Checks if self
is actually part of its subset T
(and can be converted to it).
pub fn to_subset_unchecked(&self) -> SS
pub fn to_subset_unchecked(&self) -> SS
Use with care! Same as self.to_subset
but without any property checks. Always succeeds.
pub fn from_subset(element: &SS) -> SP
pub fn from_subset(element: &SS) -> SP
The inclusion map: converts self
to the equivalent element of its superset.