Enumeration static methods

Enumerations may also have static methods. The use for static methods on the enumeration itself is primarily for alternative constructors. E.g.:

<?php

enum Size
{
    case Small;
    case Medium;
    case Large;

    public static function fromLength(int $cm): self
    {
        return match (true) {
            $cm < 50 => self::Small,
            $cm < 100 => self::Medium,
            default => self::Large,
        };
    }
}

var_dump(Size::fromLength(50));

Static methods may be public, private, or protected, although in practice private and protected are equivalent as inheritance is not allowed.