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Date: Thu, 25 May 2006 01:48:47 -0500
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To: Sara Golemon <pollita@php.net>
Cc: dante@lorenso.com, internals@lists.php.net
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Subject: Re: [PHP-DEV] Re: left/right order of assignment and ++ increment
	changed? 5.0.x -->5.1.x
From: dante@vocalspace.com ("D. Dante Lorenso")

Sara Golemon wrote:
>> Seems the order or left vs right assignment evaluation has changed 
>> somehow recently in my upgrade to PHP 5.1.4.  See the following code:
>>
> That's is indeed a quirk of a change in the way variables are 
> retreived/stored between 5.0 and 5.1.
> Is it an unexpected BC break? In functional terms yes, but technically 
> no. As mike already replied, using the same var more than once in a 
> single expression where the value of the variable is expected to 
> change is (and has always been) considered "undefined behavior".  I'd 
> recommend changing your statement to:
> $data[$index] = $index;
> ++$index;
>
> And before you complain about the "extra work" for the engine, let me 
> just mention this is still lighter weight than what 5.0 and 4.x were 
> doing.

No complaints here.  This is a change I can easily work around and don't 
mind the BC breakage.  Just wanted to illuminate the error to internals 
just in case it would reflect upon possible breakage elsewhere.  I 
worked around the undefined behavior before the first email was sent ;-)

Keep up the good work all.

Dante