A simple PHP trait that allows you to compare instances of one class to instances of any other class by implementing the getComparisonValue() method.

IsComparable.php

trait IsComparable
{
    abstract public function getComparisonValue() : int|float|string;

    /**
     * @return int<-1, 1>
     */
    public function compareTo($other) : int
    {
        if (! in_array(self::class, class_uses($other), true)) {
            throw new RuntimeException('Compared class does not use IsComparable trait!');
        }

        return $this->getComparisonValue() <=> $other->getComparisonValue();
    }
}