Re: Typed constants revisited

On Fri, Mar 25, 2022 at 10:55 AM Guilliam Xavier <guilliam.xavier@gmail.com> wrote: > I intentionally left abstract out of public > const bool CAN_FLY; in the >> abstract class for consistency with the implementation with >> interface, >> which would also have to be public const bool CAN_FLY;. >> Currently >> abstract is only used in front of methods `abstract >> function doThing(): >> bool;`. Open to discussion - which way is ideal or preferred? That could be >> included as a subset of an RFC vote if a consensus during discussion isn't >> reached. >> > > I understand, but note that methods are implicitly abstract in an > interface, but it must be explicit in an abstract class; and since I see > the proposed feature mainly as a "replacement" for abstract static methods > [whose all implementations just return a literal value]... (anyway, not > super important) > Constants are not abstract in an interface - they must be assigned a value. Only classes and methods can be abstract. Within an abstract class it is not valid to have an abstract property. Properties can be defined protected int $id; and optionally assigned a value `protected int $id = 5;, but cannot be abstract protected int $id;`. So to me it makes more sense to have constants follow the same syntax as properties `public const bool CAN_FLY; without the abstract` keyword. An example: ``` abstract class Bird { public const bool CAN_FLY; protected bool $isExtinct; ``` This allows for similar behavior, similar requirements, and similar syntax - consistency ftw! There seems to be interest and good use cases (thanks Sara for the good practical example!). At this point I'm going to work on a new RFC with all the details and feedback from this discussion.