Enum MetaItem 

pub enum MetaItem {
    Expr(MetaExpr),
    KeyValue(Ident, MetaExpr),
}

Represents a single metadata item provided as an argument to an attribute.

For example, the foo attribute in @foo(bar, baz) has two metadata items, both of Expr type, which compose a `

Variants

Expr(MetaExpr)

A metadata expression, e.g. "some text" in @foo("some text")

This represents the element type for Meta::List-based attributes.

KeyValue(Ident, MetaExpr)

A named metadata expression, e.g. letter = a in @foo(letter = a)

This represents the element type for Meta::KeyValue-based attributes.

Implementations

impl MetaItem

pub fn unwrap_expr(self) -> MetaExpr

Unwrap this item to extract the contained MetaExpr.

Panics if this item is not the Expr variant.

pub fn unwrap_key_value(self) -> (Ident, MetaExpr)

Unwrap this item to extract the contained key-value pair.

Panics if this item is not the KeyValue variant.

Trait Implementations

impl Clone for MetaItem

fn clone(&self) -> MetaItem

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl From<&str> for MetaItem

fn from(value: &str) -> Self

Converts to this type from the input type.

impl<V> From<(&str, V)> for MetaItem

where V: Into<MetaExpr>,

fn from(entry: (&str, V)) -> Self

Converts to this type from the input type.

impl<V> From<(Ident, V)> for MetaItem

where V: Into<MetaExpr>,

fn from(entry: (Ident, V)) -> Self

Converts to this type from the input type.

impl<V> From<(String, V)> for MetaItem

where V: Into<MetaExpr>,

fn from(entry: (String, V)) -> Self

Converts to this type from the input type.

impl From<Felt> for MetaItem

fn from(value: Felt) -> Self

Converts to this type from the input type.

impl From<Ident> for MetaItem

fn from(value: Ident) -> Self

Converts to this type from the input type.

impl From<String> for MetaItem

fn from(value: String) -> Self

Converts to this type from the input type.

impl From<WordValue> for MetaItem

fn from(value: WordValue) -> Self

Converts to this type from the input type.

impl From<u16> for MetaItem

fn from(value: u16) -> Self

Converts to this type from the input type.

impl From<u32> for MetaItem

fn from(value: u32) -> Self

Converts to this type from the input type.

impl From<u8> for MetaItem

fn from(value: u8) -> Self

Converts to this type from the input type.

impl FromIterator<MetaItem> for Meta

fn from_iter<T: IntoIterator<Item = MetaItem>>(iter: T) -> Self

Creates a value from an iterator.

impl PartialEq for MetaItem

fn eq(&self, other: &MetaItem) -> 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 Eq for MetaItem

impl StructuralPartialEq for MetaItem