Re: [RFC] Nullable Return Type Declaration

Hi! 2016-04-17 23:56 GMT-04:00 Larry Garfield <larry@garfieldtech.com>: > On 04/17/2016 02:19 AM, Fleshgrinder wrote: > >> Everything always has pros and cons and I do not think that there is one >> answer to all of these questions. Different languages handle this >> problem differently. PHP has NULL and we should keep it >> this way. To >> minimize bugs resulting from unchecked NULL usage a >> compiler feature >> could be implemented that warns a developer in such cases. We already >> have it for uncatched exceptions (although IDEs are currently not >> telling one about that; Eclipse does in Java though). >> > > Rather than debate the relative merits of Null as a concept, since I think > all agree removing Null from the language is not even a thing, what do you > think of my recommendation to NOT have the ? shorthand for "or null" on > types, but keep the |null for union types? That is, if you want to return > Foo or null, you have to use the long-hand version: > > function foo($a) : Foo|null > > That > > 1) Allows for explicit or-null behavior. > 2) Doesn't make it quite so easy, which hopefully discourages (but does > not prohibit) its usage. > 3) Neatly avoids the ?Foo / Foo? question entirely. > > I think that's a win-win arrangement. > > > --Larry Garfield > > -- > PHP Internals - PHP Runtime Development Mailing List > To unsubscribe, visit: http://www.php.net/unsub.php > > I can agree with that. Language design wise, if you have no way to forecast how language features independently proposed are going to interact then it's a good idea to have a converging strategy. Fortunately, this seems to be happening almost spontaneously towards union types representation, as in the "multiple catch" RFC (https://wiki.php.net/rfc/multiple-catch) now in voting phase. Even if we decide not to commit to a full union types implementation now, the design process will be much easier in the future if we decide to use Foo|null instead of Foo? or ?Foo and we will not end up with 2 or 3 ways alternative to declare the same thing. Cheers, Márcio