1.0.0[−][src]Trait nom::lib::std::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
AsRef
when the goal is to simply convert into a reference - Use
Borrow
when the goal is related to writing code that is agnostic to the type of borrow and whether it is a reference or value
See the book for a more detailed comparison.
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
AsRef
auto-dereferences if the inner type is a reference or a mutable reference (e.g.:foo.as_ref()
will work the same iffoo
has type&mut Foo
or&&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);
Required Methods
Implementations on Foreign Types
impl AsRef<OsStr> for OsStr
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impl AsRef<OsStr> for OsStr
impl AsRef<OsStr> for Path
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impl AsRef<OsStr> for Path
impl<'a> AsRef<Path> for Cow<'a, OsStr>
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impl<'a> AsRef<Path> for Cow<'a, OsStr>
impl AsRef<OsStr> for str
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impl AsRef<OsStr> for str
impl AsRef<OsStr> for OsString
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impl AsRef<OsStr> for OsString
impl<'a> AsRef<Path> for Components<'a>
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impl<'a> AsRef<Path> for Components<'a>
impl<'a> AsRef<Path> for Component<'a>
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impl<'a> AsRef<Path> for Component<'a>
impl AsRef<Path> for OsString
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impl AsRef<Path> for OsString
impl<'a> AsRef<OsStr> for Component<'a>
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impl<'a> AsRef<OsStr> for Component<'a>
impl AsRef<Path> for OsStr
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impl AsRef<Path> for OsStr
impl AsRef<Path> for PathBuf
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impl AsRef<Path> for PathBuf
impl<'a> AsRef<Path> for Iter<'a>
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impl<'a> AsRef<Path> for Iter<'a>
impl AsRef<CStr> for CString
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impl AsRef<CStr> for CString
impl AsRef<OsStr> for PathBuf
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impl AsRef<OsStr> for PathBuf
impl AsRef<Path> for str
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impl AsRef<Path> for str
impl<'a> AsRef<OsStr> for Iter<'a>
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impl<'a> AsRef<OsStr> for Iter<'a>
impl AsRef<CStr> for CStr
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impl AsRef<CStr> for CStr
impl AsRef<Path> for Path
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impl AsRef<Path> for Path
impl<'a> AsRef<OsStr> for Components<'a>
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impl<'a> AsRef<OsStr> for Components<'a>
impl<T> AsRef<[T]> for [T; 4]
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impl<T> AsRef<[T]> for [T; 4]
impl<T> AsRef<[T]> for [T; 7]
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impl<T> AsRef<[T]> for [T; 7]
impl<T> AsRef<[T]> for [T; 16]
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impl<T> AsRef<[T]> for [T; 16]
impl<T> AsRef<[T]> for [T; 2]
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impl<T> AsRef<[T]> for [T; 2]
impl<T> AsRef<[T]> for [T; 27]
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impl<T> AsRef<[T]> for [T; 27]
impl AsRef<[u8]> for str
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impl AsRef<[u8]> for str
impl<T> AsRef<[T]> for [T; 1]
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impl<T> AsRef<[T]> for [T; 1]
impl<T> AsRef<[T]> for [T; 32]
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impl<T> AsRef<[T]> for [T; 32]
impl<T> AsRef<[T]> for [T; 13]
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impl<T> AsRef<[T]> for [T; 13]
impl<T> AsRef<[T]> for [T; 6]
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impl<T> AsRef<[T]> for [T; 6]
impl<T> AsRef<[T]> for [T; 14]
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impl<T> AsRef<[T]> for [T; 14]
impl<'a, T, U> AsRef<U> for &'a T where
T: AsRef<U> + ?Sized,
U: ?Sized,
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impl<'a, T, U> AsRef<U> for &'a T where
T: AsRef<U> + ?Sized,
U: ?Sized,
impl<T> AsRef<[T]> for [T; 22]
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impl<T> AsRef<[T]> for [T; 22]
impl<T> AsRef<[T]> for [T; 24]
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impl<T> AsRef<[T]> for [T; 24]
impl<T> AsRef<[T]> for [T; 0]
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impl<T> AsRef<[T]> for [T; 0]
impl<T> AsRef<[T]> for [T; 31]
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impl<T> AsRef<[T]> for [T; 31]
impl<T> AsRef<[T]> for [T; 28]
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impl<T> AsRef<[T]> for [T; 28]
impl<T> AsRef<[T]> for [T; 25]
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impl<T> AsRef<[T]> for [T; 25]
impl<T> AsRef<[T]> for [T; 10]
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impl<T> AsRef<[T]> for [T; 10]
impl<T> AsRef<[T]> for [T; 15]
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impl<T> AsRef<[T]> for [T; 15]
impl<T> AsRef<[T]> for [T; 30]
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impl<T> AsRef<[T]> for [T; 30]
impl<T> AsRef<[T]> for [T; 8]
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impl<T> AsRef<[T]> for [T; 8]
impl<T> AsRef<[T]> for [T; 9]
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impl<T> AsRef<[T]> for [T; 9]
impl<T> AsRef<[T]> for [T; 12]
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impl<T> AsRef<[T]> for [T; 12]
impl<T> AsRef<[T]> for [T]
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impl<T> AsRef<[T]> for [T]
impl<T> AsRef<[T]> for [T; 19]
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impl<T> AsRef<[T]> for [T; 19]
impl<T> AsRef<[T]> for [T; 21]
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impl<T> AsRef<[T]> for [T; 21]
impl<T> AsRef<[T]> for [T; 20]
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impl<T> AsRef<[T]> for [T; 20]
impl<T> AsRef<[T]> for [T; 5]
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impl<T> AsRef<[T]> for [T; 5]
impl<T> AsRef<[T]> for [T; 29]
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impl<T> AsRef<[T]> for [T; 29]
impl<T> AsRef<[T]> for [T; 23]
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impl<T> AsRef<[T]> for [T; 23]
impl<T> AsRef<[T]> for [T; 18]
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impl<T> AsRef<[T]> for [T; 18]
impl<'a, T, U> AsRef<U> for &'a mut T where
T: AsRef<U> + ?Sized,
U: ?Sized,
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impl<'a, T, U> AsRef<U> for &'a mut T where
T: AsRef<U> + ?Sized,
U: ?Sized,
impl AsRef<str> for str
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impl AsRef<str> for str
impl<T> AsRef<[T]> for [T; 3]
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impl<T> AsRef<[T]> for [T; 3]
impl<T> AsRef<[T]> for [T; 11]
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impl<T> AsRef<[T]> for [T; 11]
impl<T> AsRef<[T]> for [T; 17]
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impl<T> AsRef<[T]> for [T; 17]
impl<T> AsRef<[T]> for [T; 26]
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impl<T> AsRef<[T]> for [T; 26]
impl<T> AsRef<T> for Rc<T> where
T: ?Sized,
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impl<T> AsRef<T> for Rc<T> where
T: ?Sized,
impl<'a, T> AsRef<T> for Cow<'a, T> where
T: ToOwned + ?Sized,
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impl<'a, T> AsRef<T> for Cow<'a, T> where
T: ToOwned + ?Sized,
impl<T> AsRef<T> for Arc<T> where
T: ?Sized,
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impl<T> AsRef<T> for Arc<T> where
T: ?Sized,
Implementors
impl AsRef<[u8]> for String
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impl AsRef<[u8]> for String
impl AsRef<str> for String
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impl AsRef<str> for String
impl AsRef<OsStr> for String
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impl AsRef<OsStr> for String
impl AsRef<Path> for String
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impl AsRef<Path> for String
impl<'a> AsRef<str> for CompleteStr<'a>
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impl<'a> AsRef<str> for CompleteStr<'a>
impl<'a, T> AsRef<[T]> for nom::lib::std::slice::Iter<'a, T>
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impl<'a, T> AsRef<[T]> for nom::lib::std::slice::Iter<'a, T>
impl<T> AsRef<[T]> for Vec<T>
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impl<T> AsRef<[T]> for Vec<T>
impl<T> AsRef<Vec<T>> for Vec<T>
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impl<T> AsRef<Vec<T>> for Vec<T>
impl<T> AsRef<T> for Box<T> where
T: ?Sized,
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impl<T> AsRef<T> for Box<T> where
T: ?Sized,