Struct gc::GcCellRefMut
source · pub struct GcCellRefMut<'a, T: Trace + ?Sized + 'static, U: ?Sized = T> { /* private fields */ }
Expand description
A wrapper type for a mutably borrowed value from a GcCell<T>
.
Implementations§
source§impl<'a, T: Trace + ?Sized, U: ?Sized> GcCellRefMut<'a, T, U>
impl<'a, T: Trace + ?Sized, U: ?Sized> GcCellRefMut<'a, T, U>
sourcepub fn map<V, F>(orig: Self, f: F) -> GcCellRefMut<'a, T, V>where
V: ?Sized,
F: FnOnce(&mut U) -> &mut V,
pub fn map<V, F>(orig: Self, f: F) -> GcCellRefMut<'a, T, V>where V: ?Sized, F: FnOnce(&mut U) -> &mut V,
Makes a new GcCellRefMut
for a component of the borrowed data, e.g., an enum
variant.
The GcCellRefMut
is already mutably borrowed, so this cannot fail.
This is an associated function that needs to be used as
GcCellRefMut::map(...)
. A method would interfere with methods of the same
name on the contents of a GcCell
used through Deref
.
Examples
use gc::{GcCell, GcCellRefMut};
let c = GcCell::new((5, 'b'));
{
let b1: GcCellRefMut<(u32, char)> = c.borrow_mut();
let mut b2: GcCellRefMut<(u32, char), u32> = GcCellRefMut::map(b1, |t| &mut t.0);
assert_eq!(*b2, 5);
*b2 = 42;
}
assert_eq!(*c.borrow(), (42, 'b'));
Trait Implementations§
Auto Trait Implementations§
impl<'a, T, U = T> !RefUnwindSafe for GcCellRefMut<'a, T, U>
impl<'a, T, U = T> !Send for GcCellRefMut<'a, T, U>
impl<'a, T, U = T> !Sync for GcCellRefMut<'a, T, U>
impl<'a, T: ?Sized, U: ?Sized> Unpin for GcCellRefMut<'a, T, U>
impl<'a, T, U = T> !UnwindSafe for GcCellRefMut<'a, T, U>
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more