Enumerations & bitsets¶
Use an enumeration, if you have a fixed list of values.
Use a bitset, if you have a list of boolean flags.
Do not use PHP constants directly, if your code is meant to be extendable, as constants cannot be deprecated, but the values of an enumeration or methods of a bitset can.
Background and history¶
Before version 8.1, PHP had no enumeration concept as part of the language. Therefore the TYPO3 Core includes a custom enumeration implementation.
In TYPO3, enumerations are implemented by extending the abstract class
\TYPO3\CMS\Core\Type\Enumeration. It was originally implemented similar
\SplEnum which is unfortunately part of the unmaintained package
With PHP version 8.1, an enumeration concept was implemented (see the Enumeration documentation for more details). This makes it possible to drop the custom enumeration concept from the Core in a future TYPO3 version.