Re: [RFC] Nullable Return Type Declaration

On 4/14/16 8:48 PM, Larry Garfield wrote:

I am highly, highly sceptical about nullable parameters or returns, and frankly would rather they were not included in the language. By nature they undermine type safety. At best, they indicate to all callers "*every* time you call this function, you MUST put is_null() around it or your program may fail randomly."

Yes.

While that's better to know explicitly than not (which is the case for any untyped return, aka any PHP code pre-7.0), it would be better still to, well, not have to worry about that billion dollar mistake[1] cropping up in my code.

I agree. To be clear, I do not intend the RFC to encourage nullable return or suggest that it's a fine thing to use. But given where we are, it's hard to imagine how to extirpate it. When we started using PHP 7.0 type, initially when authoring new models (and using Yii2), it immediately became clear that we lacked two things: this and void returns. We're getting the latter in 7.1. It would be very nice if we could have both. I'm a practical PHP user, with a generally conservative attitude to the language, often unmoved by proposals add a feature because some other more fashionable language has it (I call it language envy, to borrow from Freud). And while PHP 7.0 is good, I'd rather have Something|null in the return declaration than just in the docblock. That's all.

In a sense, if we really must allow for value-or-null (which I consider a code smell in the 98% case) I'd prefer if it was ONLY available via union types: That is, Something|null. That's longer and clumsier to type, and harder to read. Which it should be. (Static casts in C++ have a fugly syntax, which has been defended by the language designers on the grounds that static casts are fugly, so the syntax for them should be as well to remind you to stop doing it. There is a fair amount of validity to that argument on affordance grounds, at least within C++.) Using an easy short hand notation for something that is inherently a code smell when you're already typing your code only serves to encourage something we should be training people out of in the first place.

With regard to syntax, I prefer the long form Something|null. That seems very clear to me. The proposed short-hand ? syntax always makes me think of what I hate most about regex. Tom