Enum Meta 

pub enum Meta {
    PathValue(PathValue),
    PathList(PathList),
    Expr(Expr),
    Verbatim(TokenStream),
}

Variants

PathValue(PathValue)

A path followed by an equal sign and a single Meta — e.g. my_attribute = my_value.

PathList(PathList)

A path followed by a wrapped list of Metas — e.g. my_attribute(one, two, three). This accepts an optional equal sign before the list — e.g. my_attribute = (one, two, three).

Expr(Expr)

An expression — e.g. my_attribute, 42, "hello" or a + b.

Verbatim(TokenStream)

A verbatim token stream — e.g. [<=>]. This is the fallback for any other Meta that does not match the other variants.

Implementations

impl Meta

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

pub fn path_str(&self) -> String

Returns the path as a string if it is a valid path or an empty string if it is not a path.

pub fn is_path_or_list(&self) -> bool

pub fn is_path_or_empty_list(&self) -> bool

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

pub fn as_path_list(&self) -> Result<&PathList>

pub fn as_path_value(&self) -> Result<&PathValue>

pub fn as_value(&self) -> Result<&Meta>

pub fn as_expr_or_value_expr(&self) -> Result<&Expr>

pub fn as_expr(&self) -> Result<&Expr>

pub fn as_verbatim(&self, msg: impl Display) -> Result<&TokenStream>

pub fn assert_directive(&self, directive: &str) -> Result<&Self>

Trait Implementations

impl Debug for Meta

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

Formats the value using the given formatter.

impl From<Expr> for Meta

fn from(value: Expr) -> Self

Converts to this type from the input type.

impl From<PathList> for Meta

fn from(value: PathList) -> Self

Converts to this type from the input type.

impl From<PathValue> for Meta

fn from(value: PathValue) -> Self

Converts to this type from the input type.

impl From<TokenStream> for Meta

fn from(value: TokenStream) -> Self

Converts to this type from the input type.

impl Parse for Meta

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

impl ToTokens for Meta

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.