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To: Levi Morrison <morrison.levi@gmail.com>
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	Joe Watkins <pthreads@pthreads.org>
Thread-Topic: [PHP-DEV] [RFC] Patch for Union and Intersection Types
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Subject: Re: [PHP-DEV] [RFC] Patch for Union and Intersection Types
From: dmitry@zend.com (Dmitry Stogov)

"Foo | null" doesn't make sense without "Union Types".
Voting for one RFC first makes a preference and unfair.

Voting for two different RFCs with 2/3 majority is not good as well.
But this is the best option from my point, in case both pass we may make ad=
ditional voting with simple majority "Union" or "Nullable" or "Union+Nullab=
le".

Thanks. Dmitry.

________________________________________
From: Levi Morrison <morrison.levi@gmail.com>
Sent: Tuesday, April 26, 2016 17:47
To: Dmitry Stogov
Cc: Bob Weinand; internals; Joe Watkins
Subject: Re: [PHP-DEV] [RFC] Patch for Union and Intersection Types

On Tue, Apr 26, 2016 at 8:30 AM, Dmitry Stogov <dmitry@zend.com> wrote:
>
>
> On 04/26/2016 05:19 PM, Bob Weinand wrote:
>>>
>>> Am 26.04.2016 um 15:33 schrieb Dmitry Stogov <dmitry@zend.com>:
>>>
>>> hi Levi,
>>>
>>> It looks like your "work" on "Nullable Types" RFC was intended to win
>>> time for this patch and block "Nullable Types" again.
>>> Actually, you have been blocking it for more than a year :(
>>>
>>> I'm going to push my own RFC for voting together with "Union Types".
>>>
>>> https://wiki.php.net/rfc/nullable_return_types
>>>
>>> At least, it has up to date implementation.
>>>
>>> We discussed this internally 2-3 weeks ago, and my politeness (or/and
>>> stupidity) allowed you  to pass your version for common discussion.
>>> Now I can see your real reason :(
>>>
>>> Both "Union Types" and "Nullable Types" may make sense, and both should
>>> be voted at the same time.
>>> Tomorrow is time to start voting. Right?
>>>
>>> Thanks. Dmitry.
>>>
>>>
>>> ________________________________________
>>> From: Levi Morrison <morrison.levi@gmail.com>
>>> Sent: Tuesday, April 26, 2016 02:37
>>> To: internals
>>> Subject: [PHP-DEV] [RFC] Patch for Union and Intersection Types
>>>
>>> Internals,
>>>
>>> Joe Watkins and Bob Weinand have worked out a [proof-of-concept patch
>>> for union types][1]. Please go download it and experiment with it.
>>>
>>> A few things to note:
>>>
>>>   * This patch includes intersection types. However, a type expression
>>> must be either a union type or an intersection type; it doesn't
>>> support both such as `Array | (Countable & Traversable)`.
>>>   * This patch adds `null`, `true` and `false` for type declarations.
>>>   * This patch includes conversion rules for weak types.
>>>   * It does not have short-hand for unions with null (`?Foo` being `Foo=
 |
>>> Null`)
>>>
>>> These features (or omitted ones) are not necessarily what will be
>>> voted on. Rather this patch allows us to experiment with these
>>> features in code. This experience should be helpful for us to solidify
>>> how we actually feel about these features.
>>>
>>> I especially would like people to try out the conversion rules for
>>> scalar types as it has been a point of discussion.
>>>
>>>   [1]: https://github.com/php/php-src/pull/1887
>>
>> Hey Dmitry,
>>
>> Please, do not accuse us of blocking the nullables. This wasn't
>> intentional and rather a coincidence that we provided a patch right now.
>> First we wanted to concentrate our forces on getting a great 7.0 out
>> before starting this RFC (as it didn't make it in time for going into 7.=
0
>> too as we waited for result on scalar types in general first).
>> Then, as you're aware Levi had absolutely no time for a few months=85 No=
w,
>> he has time to manage things and we could move ahead quickly and write t=
he
>> patch up.
>
> I know, we all like to make our best for PHP.
> Sorry, if I was too emotional.
>>
>> I'd like to hold first a formal (and binding) vote on whether "null |" o=
r
>> "?" should be used (in case both RFCs pass). Rushing things through righ=
t
>> now might just us ending up with semantics the vast majority dislikes.
>
> I didn't exactly get, what do you propose. One RFC with voting for
> "Nullable" or "Union"?
>
> Thanks. Dmitry.
>
>>
>> Thanks,
>> Bob
>
>
>
>
>
>

I believe the intention here is to decide whether we do the short-hand
syntax for nullable types or only the long-form. I can understand the
rationale of not having both or at least dis-allowing the syntax to
mix them. For example, I don't think anyone really likes allowing
this: `?Array | Travsersable` as .

However, if the union types RFC does not pass then it seems odd (to me
at least) to use the expression `Foo | Null` instead of `?Foo`, but I
know Bob would like the long-form in all cases, hence why he would
like a vote. Joe seems to just want nullables to have an outcome so it
is no longer blocking typed properties.

Is that a correct summary, Bob and Joe?