Struct AttributePropertyOptionalSyn 

pub struct AttributePropertyOptionalSyn<T, Marker = AttributePropertyOptionalSynMarker>(/* private fields */)
where
    T: Parse + ToTokens;

Property of an attribute which simply wraps one of the standard syn types and keeps it optional.

Implementations

impl<T, Marker> AttributePropertyOptionalSyn<T, Marker>

where T: Parse + ToTokens,

pub fn internal(self) -> Option<T>

Just unwraps and returns the internal data.

pub fn ref_internal(&self) -> Option<&T>

Returns an Option reference to the internal data.

Methods from Deref<Target = Option<T>>

pub fn is_some(&self) -> bool

Returns true if the option is a Some value.

Examples

let x: Option<u32> = Some(2);
assert_eq!(x.is_some(), true);

let x: Option<u32> = None;
assert_eq!(x.is_some(), false);

pub fn is_none(&self) -> bool

Returns true if the option is a None value.

Examples

let x: Option<u32> = Some(2);
assert_eq!(x.is_none(), false);

let x: Option<u32> = None;
assert_eq!(x.is_none(), true);

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:?}");

pub fn as_pin_ref(self: Pin<&Option<T>>) -> Option<Pin<&T>>

Converts from Pin<&Option<T>> to Option<Pin<&T>>.

pub fn as_pin_mut(self: Pin<&mut Option<T>>) -> Option<Pin<&mut T>>

Converts from Pin<&mut Option<T>> to Option<Pin<&mut 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());
}

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);

pub fn iter(&self) -> Iter<'_, T>

Returns an iterator over the possibly contained value.

Examples

let x = Some(4);
assert_eq!(x.iter().next(), Some(&4));

let x: Option<u32> = None;
assert_eq!(x.iter().next(), None);

Trait Implementations

impl<T, Marker> AsRef<Option<T>> for AttributePropertyOptionalSyn<T, Marker>

where T: Parse + ToTokens,

fn as_ref(&self) -> &Option<T>

Converts this type into a shared reference of the (usually inferred) input type.

impl<T, Marker, IntoT> Assign<AttributePropertyOptionalSyn<T, Marker>, IntoT> for AttributePropertyOptionalSyn<T, Marker>

where T: Parse + ToTokens, IntoT: Into<AttributePropertyOptionalSyn<T, Marker>>,

fn assign(&mut self, component: IntoT)

Inserts value of another instance into the option if it is None, then returns a mutable reference to the contained value. If another instance does is None then do nothing.

fn impute(self, component: IntoT) -> Self

where Self: Sized,

Sets or replaces the component on the object with the given value. Unlike function (assing) function (impute) also consumes self and return it what is useful for builder pattern.

impl<T, Marker> AttributePropertyComponent for AttributePropertyOptionalSyn<T, Marker>

where T: Parse + ToTokens, Marker: AttributePropertyComponent,

const KEYWORD: &'static str = Marker::KEYWORD

The keyword that identifies the component.

impl<T, Marker: Clone> Clone for AttributePropertyOptionalSyn<T, Marker>

where T: Parse + ToTokens + Clone,

fn clone(&self) -> AttributePropertyOptionalSyn<T, Marker>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T, Marker: Debug> Debug for AttributePropertyOptionalSyn<T, Marker>

where T: Parse + ToTokens + Debug,

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T, Marker> Default for AttributePropertyOptionalSyn<T, Marker>

where T: Parse + ToTokens,

fn default() -> Self

Returns the “default value” for a type.

impl<T, Marker> Deref for AttributePropertyOptionalSyn<T, Marker>

where T: Parse + ToTokens,

type Target = Option<T>

The resulting type after dereferencing.

fn deref(&self) -> &Option<T>

Dereferences the value.

impl<'a, T, Marker> From<&'a AttributePropertyOptionalSyn<T, Marker>> for Option<&'a T>

where T: Parse + ToTokens,

fn from(src: &'a AttributePropertyOptionalSyn<T, Marker>) -> Self

Converts to this type from the input type.

impl<T, Marker> From<AttributePropertyOptionalSyn<T, Marker>> for Option<T>

where T: Parse + ToTokens,

fn from(src: AttributePropertyOptionalSyn<T, Marker>) -> Self

Converts to this type from the input type.

impl<T, Marker> From<Option<T>> for AttributePropertyOptionalSyn<T, Marker>

where T: Parse + ToTokens,

fn from(src: Option<T>) -> Self

Converts to this type from the input type.

impl<T, Marker> From<T> for AttributePropertyOptionalSyn<T, Marker>

where T: Parse + ToTokens,

fn from(src: T) -> Self

Converts to this type from the input type.

impl<T, Marker> Parse for AttributePropertyOptionalSyn<T, Marker>

where T: Parse + ToTokens,

fn parse(input: ParseStream<'_>) -> Result<Self>

impl<T, Marker> ToTokens for AttributePropertyOptionalSyn<T, Marker>

where T: Parse + ToTokens,

fn to_tokens(&self, tokens: &mut TokenStream)

Write self to the given TokenStream.

fn to_token_stream(&self) -> TokenStream

Convert self directly into a TokenStream object.

fn into_token_stream(self) -> TokenStream

where Self: Sized,

Convert self directly into a TokenStream object.