Re: [RFC] [Discussion] Add get_declared_enums() function

On Wed, Oct 2, 2024 at 11:06 AM Rob Landers <rob@bottled.codes> wrote: > On Wed, Oct 2, 2024, at 09:20, Alexandru Pătrănescu wrote: > > > On Wed, Oct 2, 2024 at 1:48 AM Juliette Reinders Folmer < > php-internals_nospam@adviesenzo.nl> wrote: > > L.S., > > After the earlier discussion [1] regarding this topic in August, it is our > pleasure to present the RFC to add a get_declared_enums() > function to PHP > for discussion. > > https://wiki.php.net/rfc/get_declared_enums > > We look forward to your feedback and hope for a constructive discussion. > > > I'm all for get_declared_enums(). > However, I don't accept that enums are not classes and going with the > assumption that they are not will bring more problems than it solves. > > I noticed how you analyzed things internally, that everything is a class > internally, including an interface or a trait. > But this is an API for the userland, and in userland this is not true. > The 3 structures: classes, interfaces and traits and distinct things that > you can use in different ways in (generated) code. > > I believe that in userland, the common understanding is that enums are > just a specific type of class, final ones. > I would find it surprising if get_declared_classes() would not > return > enums. > > Avoiding a BC break would be nice also if there is no reason for it. > One would be able to get only the enums by using something like: > ```php > function get_declared_enums_only() { > return array_diff(get_declared_classes(), get_declared_enums()); > } > ``` > > -- > Alex > > > Interesting observation Alexandru, > > I find it weird that class_exists("MyEnum") would return true, but there > is only one symbol table—you can’t name a class and enum with the same > name, so it makes some sense. However, while enums have “some” similarities > with classes in PHP, they are not the same. For example, you cannot > implement arbitrary interfaces (ie, Stringable), you cannot extend another > class, you cannot instantiate them with “new”, you cannot have state, you > cannot clone them, magic methods are forbidden, etc. > > You cannot build a “class” with these rules in PHP, so I don’t think enums > quack sufficiently like classes to be called a class. I would argue that it > is an object, however. I think it would be worth implementing a > get_declared_objects() that behaves like get_declared_classes() currently > does. > > — Rob > Yes, that's a good point as well. I think my view comes from when I initially dug (15+ years ago) into what an enum in Java is, and learned that it is just a syntactic sugar, and a final class would be generated implementing Comparable and extending an abstract class Enum. And I think in PHP that could be a similar view. And most of the limitations we have are not impossible to create with a standard class. I think in time we might get to remove some limitations. I, personally, don't agree with the Stringable related limitation. And also with the limitation on no state. In Java this is the simple way to create a singleton: an enum with one case; and we can't have this in PHP. If we remove the limitations, should we reclassify at that point enums as classes? -- Alex