1.0.0[−][src]Trait core::convert::AsRef
A cheap reference-to-reference conversion. Used to convert a value to a reference value within generic code.
AsRef is very similar to, but serves a slightly different purpose than,
Borrow.
AsRef is to be used when wishing to convert to a reference of another
type.
Borrow is more related to the notion of taking the reference. It is
useful when wishing to abstract over the type of reference
(&T, &mut T) or allow both the referenced and owned type to be treated
in the same manner.
The key difference between the two traits is the intention:
- Use
AsRefwhen the goal is to simply convert into a reference - Use
Borrowwhen the goal is related to writing code that is agnostic to the type of borrow and whether it is a reference or value
Note: this trait must not fail. If the conversion can fail, use a
dedicated method which returns an Option<T> or a Result<T, E>.
Generic Implementations
AsRefauto-dereferences if the inner type is a reference or a mutable reference (e.g.:foo.as_ref()will work the same iffoohas type&mut Fooor&&mut Foo)
Examples
Both String and &str implement AsRef<str>:
fn is_hello<T: AsRef<str>>(s: T) { assert_eq!("hello", s.as_ref()); } let s = "hello"; is_hello(s); let s = "hello".to_string(); is_hello(s);Run
Required methods
fn as_ref(&self) -> &T
Performs the conversion.
Implementors
impl AsRef<[u8]> for str[src]
impl AsRef<str> for str[src]
impl<T> AsRef<[T]> for [T; 0][src]
impl<T> AsRef<[T]> for [T; 1][src]
impl<T> AsRef<[T]> for [T; 2][src]
impl<T> AsRef<[T]> for [T; 3][src]
impl<T> AsRef<[T]> for [T; 4][src]
impl<T> AsRef<[T]> for [T; 5][src]
impl<T> AsRef<[T]> for [T; 6][src]
impl<T> AsRef<[T]> for [T; 7][src]
impl<T> AsRef<[T]> for [T; 8][src]
impl<T> AsRef<[T]> for [T; 9][src]
impl<T> AsRef<[T]> for [T; 10][src]
impl<T> AsRef<[T]> for [T; 11][src]
impl<T> AsRef<[T]> for [T; 12][src]
impl<T> AsRef<[T]> for [T; 13][src]
impl<T> AsRef<[T]> for [T; 14][src]
impl<T> AsRef<[T]> for [T; 15][src]
impl<T> AsRef<[T]> for [T; 16][src]
impl<T> AsRef<[T]> for [T; 17][src]
impl<T> AsRef<[T]> for [T; 18][src]
impl<T> AsRef<[T]> for [T; 19][src]
impl<T> AsRef<[T]> for [T; 20][src]
impl<T> AsRef<[T]> for [T; 21][src]
impl<T> AsRef<[T]> for [T; 22][src]
impl<T> AsRef<[T]> for [T; 23][src]
impl<T> AsRef<[T]> for [T; 24][src]
impl<T> AsRef<[T]> for [T; 25][src]
impl<T> AsRef<[T]> for [T; 26][src]
impl<T> AsRef<[T]> for [T; 27][src]
impl<T> AsRef<[T]> for [T; 28][src]
impl<T> AsRef<[T]> for [T; 29][src]
impl<T> AsRef<[T]> for [T; 30][src]
impl<T> AsRef<[T]> for [T; 31][src]
impl<T> AsRef<[T]> for [T; 32][src]
impl<T> AsRef<[T]> for [T][src]
impl<T, '_> AsRef<[T]> for Iter<'_, T>[src]
impl<T: ?Sized, U: ?Sized, '_> AsRef<U> for &'_ T where
T: AsRef<U>, [src]
T: AsRef<U>,
impl<T: ?Sized, U: ?Sized, '_> AsRef<U> for &'_ mut T where
T: AsRef<U>, [src]
T: AsRef<U>,