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Subject: Re: [PHP-DEV] RFC - Array Of for PHP 7
From: ajf@ajf.me (Andrea Faulds)

Hi Mark,

Mark Randall wrote:
> On 03/11/2017 02:27, Andrea Faulds wrote:
>> Your proposed objects would not be usable everywhere an array is,
>> because they're not arrays, and by converting to an array you lose the
>> type info, so we still have to iterate over the whole thing to type
>> check. This would be significantly less useful than an actually typed
>> array. I can see some benefit to it, but I'm not sure it's worth the
>> effort.
>
> Thanks for the reply.
>
> So if I am following right, would your goal in the short-to-mid term at
> least be to attach type information inside the HashTable, or as part of
> the zval value?

Inside the HashTable, yes. There's no space to hide it in the zval, and 
it's not the zval it's specific to anyway.

>
> I may be pulling this out our my arse of course, but does the nature of
> an array not mean that the individual values inside can be used as
> references and potentially break the type restrictions and require
> all-item checking again?
>
> $t1 = array<string>([ 'hello', 'goodbye']);
> $val = &$t1[1];
> $val = 1;
> -> [ 'hello', 1]

Yes. There's a similar problem for implementing typed property. I think 
Bob Weinand might have been working on a solution to this (typed 
references), but I have no idea where that went, if anywhere.

Thanks.
-- 
Andrea Faulds
https://ajf.me/