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Date: Thu, 21 Apr 2016 03:55:53 +1000
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To: Levi Morrison <morrison.levi@gmail.com>
Cc: internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] [RFC] Nullable Types
From: me@jesseschalken.com (Jesse Schalken)

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I read the RFC and it all sounds good to me. I appreciate the care taken to
ensure method compatibility rules are correct, a smooth interop with =null,
and to consider impact on union types if added later (? just becomes sugar).

I'm not sure if it's been mentioned or not, but the position of the ? has
impact on the ability to add a foo[] shorthand for generic arrays. Namely,
if the ? is at the start, then the syntax becomes ambiguous.

string[]? (nullable array of strings)

string?[] (array of nullable strings)

?string[] (ambiguous, need to consult precedence rules and/or use brackets)


I'm not sure how HHVM/Hack deals with that, or if it even has the foo[]
shorthand.


On Thu, Apr 14, 2016 at 1:42 PM, Levi Morrison <morrison.levi@gmail.com>
wrote:

> As alluded to in an earlier email today[1] I am now moving the
> Nullable Types RFC[2] to the discussion phase. In a nutshell this RFC
> proposes syntax for declaring a type to alternatively be null.
>
> There is a decision that needs to be made: does the question mark go
> before or after the type name?
>
>     function (?Foo $foo);
>     function (Foo? $foo);
>
> There are precedents in several languages for each position. Some
> relevant issues to where the question mark goes are noted in the
> RFC[3].
>
> I look forward to a helpful and meaningful discussion!
>
>   [1]: http://news.php.net/php.internals/92252
>   [2]: https://wiki.php.net/rfc/nullable_types
>   [3]: https://wiki.php.net/rfc/nullable_types#position_of
>
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