Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:64490
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: error (pb1.pair.com: domain mrclay.org from 50.22.11.19 cause and error)
Message-ID: <50E4D0BB.7060701@mrclay.org>
Date: Wed, 02 Jan 2013 19:28:43 -0500
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:17.0) Gecko/17.0 Thunderbird/17.0
MIME-Version: 1.0
To: Clint Priest <cpriest@zerocue.com>, 
 PHP Internals <internals@lists.php.net>
References: <50E41BB6.4030901@zerocue.com> <CADEasVEHFOgC_f-YFHPu4JoWogLgjiLouNX55oQUgSDyLM_Ggg@mail.gmail.com> <50E4A43E.6030302@zerocue.com> <50E4B232.5000505@mrclay.org> <50E4BDDE.8050509@zerocue.com>
In-Reply-To: <50E4BDDE.8050509@zerocue.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Subject: Re: [PHP-DEV] [PHP-RFC] Property Accessors 1.2 for Final Review before
 Vote
From: steve@mrclay.org (Steve Clay)

On 1/2/13 6:08 PM, Clint Priest wrote:
> Sorry, there was a typo in that RFC there, this line:
>          isset { return $this->Hours != NULL; }
> Should have been with !==:
>          isset { return $this->Hours !== NULL; }
>
> I've already updated the 1.2 doc to reflect the correct way.
>
> Given what I mentioned above, I'm assuming you did not test this with the fork, right?
> Just based your comments on how it should logically work (with the incorrect != vs !==?)

I haven't tested the fork. I just borrowed your logic with the typo :)

> One last thing about that, the isset/unset with $this->Hours calls the getter to retrieve
> the $this->Hours value, so it behaves as your example below indicates.

The RFC says, "only the accessors themselves may directly access the shadowed property." I 
read that as:

   Within get,   $this->Hours is the raw shadowed property.
   Within set,   $this->Hours is the raw shadowed property.
   Within isset, $this->Hours is the raw shadowed property.
   Within unset, $this->Hours is the raw shadowed property.

But you seem to imply:

   Within get,   $this->Hours is the raw shadowed property.
   Within set,   $this->Hours is the raw shadowed property.
   Within isset, $this->Hours is accessed via __getHours()/__setHours().
   Within unset, $this->Hours is accessed via __getHours()/__setHours().

So really the default implementations behave like this:

   isset { return $this->__getHours() !== NULL; }
   unset { $this->__setHours(NULL); }

I think the RFC should be much clearer about what property access actually means within 
each accessor method, as I expect users to be very surprised by this behavior.

This is also looks like it could lead to surprises:

   Within get, $this->Hours is the raw shadowed property.
   Within get, parent::$Hours is accessed via parent::__getHours()/parent::__setHours().

Also, is there no way to access the shadow property within isset/unset? If not, is there a 
good reason to not allow it?


Also, do/should multiple property accessors interact? Consider:

class Foo {
     public $a {
         get { $this->a = 1; return 2; }
     }
     public $b {
         get { return $this->a; }
     }
}

$foo = new Foo;
$foo->a; // 2 (but shadowed property is 1)
$foo->b; // 1 or 2?


Steve Clay
-- 
http://www.mrclay.org/