Enum syn::Meta

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pub enum Meta {
    Path(Path),
    List(MetaList),
    NameValue(MetaNameValue),
}
Expand description

Content of a compile-time structured attribute.

Path

A meta path is like the test in #[test].

List

A meta list is like the derive(Copy) in #[derive(Copy)].

NameValue

A name-value meta is like the path = "..." in #[path = "sys/windows.rs"].

Syntax tree enum

This type is a syntax tree enum.

Variants§

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Path(Path)

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List(MetaList)

A structured list within an attribute, like derive(Copy, Clone).

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NameValue(MetaNameValue)

A name-value pair within an attribute, like feature = "nightly".

Implementations§

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impl Meta

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pub fn path(&self) -> &Path

Returns the path that begins this structured meta item.

For example this would return the test in #[test], the derive in #[derive(Copy)], and the path in #[path = "sys/windows.rs"].

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pub fn require_path_only(&self) -> Result<&Path>

Error if this is a Meta::List or Meta::NameValue.

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pub fn require_list(&self) -> Result<&MetaList>

Error if this is a Meta::Path or Meta::NameValue.

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pub fn require_name_value(&self) -> Result<&MetaNameValue>

Error if this is a Meta::Path or Meta::List.

Trait Implementations§

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impl Clone for Meta

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fn clone(&self) -> Self

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for Meta

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

Formats the value using the given formatter. Read more
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impl From<MetaList> for Meta

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fn from(e: MetaList) -> Meta

Converts to this type from the input type.
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impl From<MetaNameValue> for Meta

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fn from(e: MetaNameValue) -> Meta

Converts to this type from the input type.
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impl From<Path> for Meta

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fn from(e: Path) -> Meta

Converts to this type from the input type.
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impl Hash for Meta

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fn hash<H>(&self, state: &mut H)
where H: Hasher,

Feeds this value into the given Hasher. Read more
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fn hash_slice<H>(data: &[Self], state: &mut H)
where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
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impl Parse for Meta

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

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impl PartialEq for Meta

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fn eq(&self, other: &Self) -> bool

This method tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl ToTokens for Meta

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

Write self to the given TokenStream. Read more
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fn to_token_stream(&self) -> TokenStream

Convert self directly into a TokenStream object. Read more
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fn into_token_stream(self) -> TokenStream
where Self: Sized,

Convert self directly into a TokenStream object. Read more
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impl Eq for Meta

Auto Trait Implementations§

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impl RefUnwindSafe for Meta

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impl !Send for Meta

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impl !Sync for Meta

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impl Unpin for Meta

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impl UnwindSafe for Meta

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> Spanned for T
where T: Spanned + ?Sized,

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fn span(&self) -> Span

Returns a Span covering the complete contents of this syntax tree node, or Span::call_site() if this node is empty.
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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.