Trait PositionIndex

pub trait PositionIndex: VariantCount {
    // Required methods
    fn index(&self) -> usize;
    fn position_of(index: usize) -> Option<Self>
       where Self: Sized;
}

Maps semantic variants to zero-based position indices.

VariantCount is 1-based, while PositionIndex is 0-based. As a result, the maximum valid index is VariantCount::VARIANT_COUNT - 1.

Required Methods

fn index(&self) -> usize

Returns the zero-based index for this variant, or None if the variant must not participate in indexing.

fn position_of(index: usize) -> Option<Self>

where Self: Sized,

Returns the variant for the given zero-based index, or None if the index is out of range or non-semantic.

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.

Implementors

impl PositionIndex for Disposition

impl PositionIndex for Polarity

impl PositionIndex for Ignore

Trivial implementation for marker type Ignore, representing a single, non-variant position.