struct META_FULL_PATH {
__private_field: (),
}
Fields§
§__private_field: ()
Methods from Deref<Target = Option<Arc<Path>>>§
1.0.0 · Sourcepub fn as_ref(&self) -> Option<&T>
pub fn as_ref(&self) -> Option<&T>
Converts from &Option<T>
to Option<&T>
.
§Examples
Calculates the length of an Option<String>
as an Option<usize>
without moving the String
. The map
method takes the self
argument by value,
consuming the original, so this technique uses as_ref
to first take an Option
to a
reference to the value inside the original.
let text: Option<String> = Some("Hello, world!".to_string());
// First, cast `Option<String>` to `Option<&String>` with `as_ref`,
// then consume *that* with `map`, leaving `text` on the stack.
let text_length: Option<usize> = text.as_ref().map(|s| s.len());
println!("still can print text: {text:?}");
1.75.0 · Sourcepub fn as_slice(&self) -> &[T]
pub fn as_slice(&self) -> &[T]
Returns a slice of the contained value, if any. If this is None
, an
empty slice is returned. This can be useful to have a single type of
iterator over an Option
or slice.
Note: Should you have an Option<&T>
and wish to get a slice of T
,
you can unpack it via opt.map_or(&[], std::slice::from_ref)
.
§Examples
assert_eq!(
[Some(1234).as_slice(), None.as_slice()],
[&[1234][..], &[][..]],
);
The inverse of this function is (discounting
borrowing) [_]::first
:
for i in [Some(1234_u16), None] {
assert_eq!(i.as_ref(), i.as_slice().first());
}
1.40.0 · Sourcepub fn as_deref(&self) -> Option<&<T as Deref>::Target>where
T: Deref,
pub fn as_deref(&self) -> Option<&<T as Deref>::Target>where
T: Deref,
Converts from Option<T>
(or &Option<T>
) to Option<&T::Target>
.
Leaves the original Option in-place, creating a new one with a reference
to the original one, additionally coercing the contents via Deref
.
§Examples
let x: Option<String> = Some("hey".to_owned());
assert_eq!(x.as_deref(), Some("hey"));
let x: Option<String> = None;
assert_eq!(x.as_deref(), None);
Trait Implementations§
Source§impl Deref for META_FULL_PATH
impl Deref for META_FULL_PATH
impl LazyStatic for META_FULL_PATH
Auto Trait Implementations§
impl Freeze for META_FULL_PATH
impl RefUnwindSafe for META_FULL_PATH
impl Send for META_FULL_PATH
impl Sync for META_FULL_PATH
impl Unpin for META_FULL_PATH
impl UnwindSafe for META_FULL_PATH
Blanket Implementations§
§impl<T> ArchivePointee for T
impl<T> ArchivePointee for T
§type ArchivedMetadata = ()
type ArchivedMetadata = ()
§fn pointer_metadata(
_: &<T as ArchivePointee>::ArchivedMetadata,
) -> <T as Pointee>::Metadata
fn pointer_metadata( _: &<T as ArchivePointee>::ArchivedMetadata, ) -> <T as Pointee>::Metadata
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
§impl<F, W, T, D> Deserialize<With<T, W>, D> for F
impl<F, W, T, D> Deserialize<With<T, W>, D> for F
§fn deserialize(
&self,
deserializer: &mut D,
) -> Result<With<T, W>, <D as Fallible>::Error>
fn deserialize( &self, deserializer: &mut D, ) -> Result<With<T, W>, <D as Fallible>::Error>
§impl<T> Downcast for Twhere
T: Any,
impl<T> Downcast for Twhere
T: Any,
§fn into_any(self: Box<T>) -> Box<dyn Any>
fn into_any(self: Box<T>) -> Box<dyn Any>
Box<dyn Trait>
(where Trait: Downcast
) to Box<dyn Any>
, which can then be
downcast
into Box<dyn ConcreteType>
where ConcreteType
implements Trait
.§fn into_any_rc(self: Rc<T>) -> Rc<dyn Any>
fn into_any_rc(self: Rc<T>) -> Rc<dyn Any>
Rc<Trait>
(where Trait: Downcast
) to Rc<Any>
, which can then be further
downcast
into Rc<ConcreteType>
where ConcreteType
implements Trait
.§fn as_any(&self) -> &(dyn Any + 'static)
fn as_any(&self) -> &(dyn Any + 'static)
&Trait
(where Trait: Downcast
) to &Any
. This is needed since Rust cannot
generate &Any
’s vtable from &Trait
’s.§fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)
fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)
&mut Trait
(where Trait: Downcast
) to &Any
. This is needed since Rust cannot
generate &mut Any
’s vtable from &mut Trait
’s.§impl<T> DowncastSend for T
impl<T> DowncastSend for T
§impl<T> DowncastSync for T
impl<T> DowncastSync for T
§impl<T> Instrument for T
impl<T> Instrument for T
§fn instrument(self, span: Span) -> Instrumented<Self> ⓘ
fn instrument(self, span: Span) -> Instrumented<Self> ⓘ
§fn in_current_span(self) -> Instrumented<Self> ⓘ
fn in_current_span(self) -> Instrumented<Self> ⓘ
Source§impl<T> IntoEither for T
impl<T> IntoEither for T
Source§fn into_either(self, into_left: bool) -> Either<Self, Self>
fn into_either(self, into_left: bool) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left
is true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read moreSource§fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left(&self)
returns true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read more