Am 25.04.2021 um 05:47 schrieb Larry Garfield <la...@garfieldtech.com>:
> In practice, I think all of the use cases for sealed classes are ADT-esque.
> As I noted before, combining sealed classes with Nikita's new-in-expressions
> RFC would allow for this (also using my short-functions RFC for this example,
> although that's a nice-to-have):
>
> sealed class Maybe permits Some, None {
...
> }
>
> final class None extends Maybe {}
This is exactly the thing I'm worried about.
Say I want to add something like logging to the None type.
Now your sealed and final classes prevent me from defining MyNone extending
None even though it would be 100% compatible with None. Just because *you*
deemed that useless or wrong.
I've encountered situations like this and came to the conclusion that while
this makes sense for languages like Haskell - where the whole idea is to be
able to reason about a complex type system - it is an anti-pattern for other
languages like PHP.
Referring to another post, not yours: People, please don't use Java as a reason
to add something to PHP, Java is the king of anti-patterns ;-)
- Chris
