Trait Enumable 

pub trait Enumable: Copy + 'static {
    const VARIANTS: &'static [Self];
    const COUNT: usize = _;

    // Provided method
    fn variant_index(&self) -> usize { ... }
}

A trait for enumerations that can be used with EnumTable.

This trait requires that the enumeration provides a static array of its variants and a constant representing the count of these variants.

Safety

The implementations of this trait rely on the memory layout of the enum. It is strongly recommended to use a primitive representation (e.g., #[repr(u8)]) to ensure that the enum has no padding bytes and a stable layout.

Note on Padding: If the enum contains padding bytes (e.g., #[repr(u8, align(2))]), it will cause a compile-time error during constant evaluation, as Rust’s constant evaluator does not allow reading uninitialized memory (padding).

Required Associated Constants

const VARIANTS: &'static [Self]

Provided Associated Constants

const COUNT: usize = _

Provided Methods

fn variant_index(&self) -> usize

Returns the index of this variant in the sorted VARIANTS array.

When derived via #[derive(Enumable)], this is O(1) at runtime (using compile-time-computed constants). The default implementation falls back to O(log N) binary search for manual implementations.

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