Hi Internals,
I want to introduce the `static` keyword at the class declaration level.
That is, the following would be valid: `static class Foo {}`.
A "static class" is one that only permits static members
(methods/properties) and could have similar semantics to a static class
in C#
<https://learn.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/static-classes-and-static-class-members>.
In particular: static classes are implied final and they cannot inherit
from any other class. These specific semantics are negotiable, but in
practice I've never seen the need to mix inheritance with pure static
classes.
A static class can be emulated somewhat with a trait in userland, and I
have long used such a micro library for this purpose
<https://github.com/ScriptFUSION/StaticClass/blob/master/src/StaticClass.php>.
This works by forcing the constructor to be private, thus preventing
instantiation, but it cannot guarantee that the consumer does not create
any instance methods anyway (just that such methods would be useless as
they would be inaccessible). Ergo, it would be better to have this as a
language feature so the compiler can provide the necessary guarantees
and warnings against improper use.
I am not too familiar with internals, but I figure I can probably muddle
my way through an implementation by following the readonly PR
<https://github.com/php/php-src/pull/7305/files>, which I imagine has
similar touch points. The main thing I'd like to ascertain at this stage
is whether such a PR would have support?
Kind regards,
Bilge
- [PHP-DEV] Static class Bilge
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