1.0.0[][src]Struct std::cell::Ref

pub struct Ref<'b, T> where
    T: 'b + 'b + ?Sized
{ /* fields omitted */ }

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
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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]

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
[src]

🔬 This is a nightly-only experimental API. (refcell_map_split #51476)

Splits a Ref into multiple Refs 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

#![feature(refcell_map_split)]
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> Display for Ref<'_, T> where
    T: Display + ?Sized
1.20.0
[src]

impl<'b, T, U> CoerceUnsized<Ref<'b, U>> for Ref<'b, T> where
    T: Unsize<U> + ?Sized,
    U: ?Sized
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impl<'_, T> Debug for Ref<'_, T> where
    T: Debug + ?Sized
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impl<'_, T> Deref for Ref<'_, T> where
    T: ?Sized
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type Target = T

The resulting type after dereferencing.

Auto Trait Implementations

impl<'b, T> !Send for Ref<'b, T>

impl<'b, T> !Sync for Ref<'b, T>

Blanket Implementations

impl<T> From for T[src]

impl<T, U> TryFrom for T where
    U: Into<T>, 
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type Error = Infallible

The type returned in the event of a conversion error.

impl<T, U> TryInto for T where
    U: TryFrom<T>, 
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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.

impl<T, U> Into for T where
    U: From<T>, 
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impl<T> Borrow for T where
    T: ?Sized
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impl<T> BorrowMut for T where
    T: ?Sized
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impl<T> Any for T where
    T: 'static + ?Sized
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impl<T> ToString for T where
    T: Display + ?Sized
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