Enum `Meta`

pub enum Meta

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

Path(Path)
List(MetaList): A structured list within an attribute, like derive(Copy, Clone).
NameValue(MetaNameValue): A name-value pair within an attribute, like feature = "nightly".

Implementations

`impl Meta`

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"].

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

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

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

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

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

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

Trait Implementations

`impl Clone for Meta`

fn clone(&self) -> Self

`impl From<MetaList> for Meta`

fn from(meta: MetaList) -> Meta

`impl From<MetaNameValue> for Meta`

fn from(meta: MetaNameValue) -> Meta

`impl From<Path> for Meta`

fn from(meta: Path) -> Meta

`impl Parse for Meta`

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

`impl ToTokens for Meta`

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

Auto Trait Implementations

`impl !Send for Meta`

`impl !Sync for Meta`

`impl Freeze for Meta`

`impl RefUnwindSafe for Meta`

`impl Unpin for Meta`

`impl UnsafeUnpin for Meta`

`impl UnwindSafe for Meta`

Blanket Implementations

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

fn type_id(&self) -> TypeId

`impl<T> Borrow<T> for Meta where T: ?Sized,`

fn borrow(&self) -> &T

`impl<T> BorrowMut<T> for Meta where T: ?Sized,`

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

`impl<T> CloneToUninit for Meta where T: Clone,`

unsafe fn clone_to_uninit(&self, dest: *mut u8)

`impl<T> From<T> for Meta`

fn from(t: T) -> T: Returns the argument unchanged.

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

fn span(&self) -> Span

`impl<T> ToOwned for Meta where T: Clone,`

type Owned = T;
fn to_owned(&self) -> T
fn clone_into(&self, target: &mut T)

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

fn into(self) -> U

Calls U::from(self).

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

`impl<T, U> TryFrom for Meta where U: Into<T>,`

type Error = never;
fn try_from(value: U) -> Result<T, never>

`impl<T, U> TryInto for Meta where U: TryFrom<T>,`

type Error = >::Error;
fn try_into(self) -> Result<U, >::Error>