Enum Meta

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

Available on crate features full or derive only.

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

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"].

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

Available on crate feature parsing only.

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

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

Available on crate feature parsing only.

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

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

Available on crate feature parsing only.

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

Trait Implementations

impl Clone for Meta

Available on crate feature clone-impls only.

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Meta

Available on crate feature extra-traits only.

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

Formats the value using the given formatter.

impl From<MetaList> for Meta

fn from(meta: MetaList) -> Meta

Converts to this type from the input type.

impl From<MetaNameValue> for Meta

fn from(meta: MetaNameValue) -> Meta

Converts to this type from the input type.

impl From<Path> for Meta

fn from(meta: Path) -> Meta

Converts to this type from the input type.

impl Hash for Meta

Available on crate feature extra-traits only.

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

where H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Parse for Meta

Available on crate feature parsing only.

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

impl PartialEq for Meta

Available on crate feature extra-traits only.

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

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl ToTokens for Meta

Available on crate feature printing only.

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.

impl Eq for Meta

Available on crate feature extra-traits only.

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 232 bytes

Size for each variant:

• Path: 56 bytes
• List: 104 bytes
• NameValue: 232 bytes