Trait AttributePositional

pub trait AttributePositional: AttributeBase {
    // Required method
    fn parse_positional(
        input: ParseStream<'_>,
    ) -> Result<Option<SpannedValue<Self::Partial>>>;
}

Values that can be parsed positionally, i.e., without a name, e.g. "literal", a + b, true.

When deriving FromAttr this behavior is enabled via putting #[attr(positional)] on the field.

The trait is implemented for each AttributeValue that implements the marker trait PositionalValue.

Required Methods

fn parse_positional( input: ParseStream<'_>, ) -> Result<Option<SpannedValue<Self::Partial>>>

Parses Self, positionally.

Note: This needs to stop parsing at the end of the value, before a possible following , and further arguments.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl AttributePositional for bool

fn parse_positional( input: ParseStream<'_>, ) -> Result<Option<SpannedValue<Self::Partial>>>

impl<T: AttributePositional + AttributePeekable> AttributePositional for Option<T>

fn parse_positional( input: ParseStream<'_>, ) -> Result<Option<SpannedValue<Self::Partial>>>

Implementors

impl<T: AttributeValue + PositionalValue> AttributePositional for T