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Date: Thu, 17 Jan 2013 17:24:35 -0500
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Subject: Re: [PHP-DEV] [VOTE] Property Accessors for 5.5
From: steve@mrclay.org (Steve Clay)

On 1/17/13 1:20 PM, Clint Priest wrote:
> I'm happy to say that Property Accessors is ready for a vote for inclusion in 5.5 release.
>
> Nikita and I (as well as Stas a bit) have all been working hard to make this happen for
> 5.5, voting and the specifications are here:

 > https://wiki.php.net/rfc/propertygetsetsyntax-v1.2#voting

I'll say my peace on this. This is a very good implementation, and as long as authors use 
accessors that depend on a separate property for storage (like other langs require), 
everything will be straightforward. Otherwise, I fear they're in for some confusing behavior.

Consider the code from the RFC:

class TimePeriod {
     public $Hours {
         get { return $this->Hours ?: "not specified"; }
         set { $this->Hours = $value; }
     }
}

$tp = new TimePeriod();
$tp->Hours; // "not specified"
isset($tp->Hours); // true!?

The auto implementation of isset compares $this->Hours to NULL, but since $this->Hours 
goes through the getter, it will return "not specified". So the property will always 
appear to be isset.

* The guards seem spooky: A set of tokens ($this->prop) will have varying behavior (e.g. 
direct prop read vs. getter call) *depending on the call stack*.

* Giving issetter/unsetter no direct access to the property limits functionality and leads 
to weirdness like the example above.


Steve Clay
-- 
http://www.mrclay.org/