1.0.0[][src]Trait std::convert::AsRef

pub trait AsRef<T> where
    T: ?Sized
{ fn as_ref(&self) -> &T; }

Used to do a cheap reference-to-reference conversion.

This trait is similar to AsMut which is used for converting between mutable references. If you need to do a costly conversion it is better to implement From with type &T or write a custom function.

AsRef has the same signature as Borrow, but Borrow is different in few aspects:

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

Examples

By using trait bounds we can accept arguments of different types as long as they can be converted to the specified type T.

For example: By creating a generic function that takes an AsRef<str> we express that we want to accept all references that can be converted to &str as an argument. Since both String and &str implement AsRef<str> we can accept both as input argument.

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

Important traits for &'_ mut I
fn as_ref(&self) -> &T

Performs the conversion.

Loading content...

Implementors

impl AsRef<[u8]> for str[src]

impl AsRef<[u8]> for String[src]

impl AsRef<str> for str[src]

impl AsRef<str> for String[src]

impl AsRef<CStr> for CStr[src]

impl AsRef<CStr> for CString[src]

impl AsRef<OsStr> for str[src]

impl AsRef<OsStr> for OsStr[src]

impl AsRef<OsStr> for OsString[src]

impl AsRef<OsStr> for Path[src]

impl AsRef<OsStr> for PathBuf[src]

impl AsRef<OsStr> for String[src]

impl AsRef<Path> for str[src]

impl AsRef<Path> for OsStr[src]

impl AsRef<Path> for OsString[src]

impl AsRef<Path> for Path[src]

impl AsRef<Path> for PathBuf[src]

impl AsRef<Path> for String[src]

impl<'_> AsRef<OsStr> for Component<'_>[src]

impl<'_> AsRef<OsStr> for Components<'_>[src]

impl<'_> AsRef<OsStr> for std::path::Iter<'_>[src]

impl<'_> AsRef<Path> for Cow<'_, OsStr>[src]

impl<'_> AsRef<Path> for Component<'_>[src]

impl<'_> AsRef<Path> for Components<'_>[src]

impl<'_> AsRef<Path> for std::path::Iter<'_>[src]

impl<'_, T> AsRef<[T]> for std::slice::Iter<'_, T>[src]

impl<'_, T> AsRef<T> for Cow<'_, T> where
    T: ToOwned + ?Sized
[src]

impl<'_, T, U> AsRef<U> for &'_ T where
    T: AsRef<U> + ?Sized,
    U: ?Sized
[src]

impl<'_, T, U> AsRef<U> for &'_ mut T where
    T: AsRef<U> + ?Sized,
    U: ?Sized
[src]

impl<T> AsRef<[T]> for [T][src]

impl<T> AsRef<[T]> for Vec<T>[src]

impl<T> AsRef<Vec<T>> for Vec<T>[src]

impl<T> AsRef<T> for Box<T> where
    T: ?Sized
[src]

impl<T> AsRef<T> for Rc<T> where
    T: ?Sized
[src]

impl<T> AsRef<T> for Arc<T> where
    T: ?Sized
[src]

impl<const N: usize, T> AsRef<[T]> for [T; N] where
    [T; N]: LengthAtMost32
[src]

Loading content...