What is an enumeration (enum) in PHP and in what context is it used?

In PHP, an enumeration (enum) is a special data type introduced starting from version 8.1, which allows defining a set of named constants. Enums are used to restrict a variable's value to a specific set of options, enhancing code readability and safety.

Example of using enum:

enum Status {
    case Draft;
    case Published;
    case Archived;
}

function publish(Status $status) {
    if ($status === Status::Draft) {
        // publishing logic
    }
}

publish(Status::Draft);

Thus, enum helps explicitly specify valid values and avoid errors related to passing incorrect data.