Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:91869
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Message-ID: <90.F4.30596.770A1F65@pb1.pair.com>
To: internals@lists.php.net
References: <CABDNdAHwgx+LJRc_gi9citiypxxWVGFMB+6hrmU+vVYDWCDV_g@mail.gmail.com>
 <56E9C241.1090905@fleshgrinder.com> <3B.AA.03097.757BDE65@pb1.pair.com>
 <56EEA379.20503@fleshgrinder.com>
Date: Tue, 22 Mar 2016 19:43:47 +0000
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:43.0)
 Gecko/20100101 Firefox/43.0 SeaMonkey/2.40
MIME-Version: 1.0
In-Reply-To: <56EEA379.20503@fleshgrinder.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Subject: Re: [PHP-DEV] [RFC Discussion] Typed Properties
From: ajf@ajf.me (Andrea Faulds)

Hi again,

Fleshgrinder wrote:
> On 3/19/2016 9:32 PM, Andrea Faulds wrote:
>> Fleshgrinder wrote:
>>> I see a big problem with the erroring no matter when as others already
>>> pointed out, e.g. together with named constructors (or factory methods
>>> if you prefer that name) but also with lazy loading. I think that the
>>> null value of properties during and after construction should simply be
>>> ignored and left to the implementer. I know that it would be nice to
>>> have 100% assurance that the property is always set but it would simply
>>> result in rules that are too strict for various use cases. I mean,
>>> aren't we trying to solve a problem that never was a problem here?
>>
>> This is actually a problem for optimising PHP. If the compiler cannot be
>> sure a property's value actually matches its declared type, it can't
>> optimise operations on that property to remove a type check.
>>
>
> Can we optimize operations or is this theoretical?

We can do it, in fact as of a week ago PHP 7.1 (or rather the master 
branch of php-src) has type-specialised opcodes: 
https://github.com/php/php-src/pull/1825

I haven't looked at Optimizer's type-inference code, but I don't think 
it currently applies to properties. It would be great if we could extend 
it to them using the information typed properties provide us, though.

> On 3/19/2016 9:32 PM, Andrea Faulds wrote:
>> I also think it would be unintuitive if typed properties had some
>> exception where they don't obey the given type. If I ask for an integer,
>> then surely I should get an integer?
>>
>
> Of course but there is some *void* time until an object is fully
> initialized. We've seen many examples now in this thread.

That still complicates things. If you need to convert types, I would 
suggest using something akin to __wakeup or some method to import data 
from an array. Then you could handle type conversion yourself before 
assigining to properties.

Thanks.
-- 
Andrea Faulds
https://ajf.me/