Re: Optional interfaces

On Sat, Nov 16, 2024, at 01:27, Marco Aurélio Deleu wrote: > >> On 15 Nov 2024, at 20:42, Rob Landers <rob@bottled.codes> wrote: >>  >> On Sat, Nov 16, 2024, at 00:34, Juris Evertovskis wrote: >>> Hey all, >>> >>> If you try to implement an interface that does not exist, you get the ‘Interface >>> “%s” not found’ error. Usually that’s useful as it points to a code error. >>> >>> However, sometimes we want our code to be compatible with an optional library. For >>> example, my Expression class might be compatible with some ORM, but it would also usable without it >>> or with another ORM. This can already be accomplished, but the solutions seems very workaroundish: >>> https://stackoverflow.com/questions/57996429/implements-interface-only-if-exists >>> >>> Maybe the PHP itself should allow marking some interfaces as optional — such that >>> they are discarded from the list if the interface class does not exist? Here’s one way the syntax >>> could look like: >>> >>> class Expression implements MyInterface, ?OptionalInterface {} >>> >>> interface EventDispatcherInterface extends ?PsrEventDispatcherInterface {} >>> >>> BR, >>> Juris >> >> Hey Juris, >> >> Is there some reason you cannot do this: >> >> https://3v4l.org/hF1vr >> >> — Rob > > That seems to match what he shared on SO link? Thanks Marco, I don't visit stackoverflow because I loath "features locked behind internet points". Thanks for letting me know what is behind the link! > > I think I opened this email with a strong negative feeling towards what would be optional > interface, but to be honest a syntax sugar where implements ?MyInterface becomes something pretty > close to what Rob shared doesn’t sound bad, it’s just convenience. Unfortunately PHP is not keen > on being open to those. > > Overall, I dig it. I maintain a PHP SDK that needs to be compatible with Symfony and Laravel and any other framework. The shenanigans are all bound in one file that I very rarely touch. So, I do kinda like the idea of having optional interfaces, but I feel like it is rather niche. As an application developer, I can't think of one time I've ever needed this. However, the single biggest advantage comes from IDEs that can somehow show that there is an optional interface on a type. I think that would be the most useful bit to come from this, honestly. It also prevents IDEs or static analysis from giving a warning that there are multiple definitions of an interface if you have the appropriate libraries installed. It's also rather simple to implement, so I think it is worth pursuing, IMHO. — Rob