Alex, On Wed, Mar 30, 2022 at 7:47 AM Alexandru Pătrănescu <dreal...@gmail.com> wrote:
> Hey Mark, > > On Wed, Mar 30, 2022 at 4:01 PM Mark Niebergall <mbnieberg...@gmail.com> > wrote: > >> Alex, >> >> On Tue, Mar 29, 2022 at 10:35 PM Alexandru Pătrănescu <dreal...@gmail.com> >> wrote: >> >>> Hey Mark, >>> >>> >>> On Wed, Mar 30, 2022 at 6:03 AM Mark Niebergall <mbnieberg...@gmail.com> >>> wrote: >>> >>>> >>>> I have updated the RFC https://wiki.php.net/rfc/typed_class_constants >>>> with >>>> more details and examples from this thread, and updated the RFC status >>>> to >>>> Under Discussion. Hopefully the updated RFC helps answer questions and >>>> clarifies what the proposal includes. >>>> >>> >>> Thanks for the RFC and the drive here. >>> I personally see the benefit and I think it would be a nice addition. >>> >>> I think you should also update the "Supported types" section. >>> Starting with enums, constants can also be objects. Once a good >>> technical solution is found, any object would be supported probably >>> https://wiki.php.net/rfc/new_in_initializers#future_scope >>> I think that only void, never and callable types should not be >>> supported, just like on properties. >>> >>> >> I have updated the "Supported types" to list out all types that are >> supported and which types are not supported. >> >> Constants cannot be objects since objects are mutable, so typed constants >> will not be allowed to be an enum (which is technically an object). A typed >> constant _may_ be an enum value though, so the following example will be >> valid: >> >> ``` >> enum Fruit >> { >> case Apple; >> case Banana; >> } >> >> class Colors >> { >> protected const string RED = Fruit::Apple; >> protected const string YELLOW = Fruit::Banana; >> } >> ``` >> > > Actually, Fruit::Apple is an enum instance and that is an object that is > of Fruit enum type (Fruit class). > You can check this as it's already possible in PHP 8.1, even if it's not > yet possible to have them with type: https://3v4l.org/f4WIC > > What you are referring to as enum value is actually a backed value for an > enum instance. > If you would define the enum as > ``` > enum Fruit: string > { > case Apple = 'apple'; > case Banana = 'banana'; > } > ``` > You could obtain the value with Fruit::Apple->value. But I'm not > referring to this. > > So going back to the topic I mentioned, a constant can right now be an > object. > It can be only an enum instance for now but I believe that in the near > future we will be able to have any object there. > Ah yes, you are correct, my mistake. I will need to make some more updates to the RFC page to address that. > > Also, self and parent would make sense for valid typed constants, just > like they do work on properties. > I'll add examples and an item about this as well. > > Regards, > Alex > > >> >>> >>>> Of note is the "Inheritance and variance" section, which details uses >>>> with >>>> abstracts and interfaces, plus the "Constant values" section which >>>> includes >>>> details about errors. >>>> >>>> >>>> > >>>> > -- >>>> > Guilliam Xavier >>>> > >>>> >>> >>> Thanks, >>> Alex >>> >>
