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Date: Fri, 08 Apr 2011 12:49:09 +1000
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To: Rasmus Lerdorf <rasmus@lerdorf.com>
CC: Rafael Dohms <listas@rafaeldohms.com.br>,
  internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Implicit isset/isempty check on short-ternary operator
From: mail_ben_schmidt@yahoo.com.au (Ben Schmidt)

On 8/04/11 4:41 AM, Rasmus Lerdorf wrote:
> On 4/7/11 2:30 PM, Rafael Dohms wrote:
>> On Thu, Mar 31, 2011 at 7:46 PM, Ben Schmidt
>> <mail_ben_schmidt@yahoo.com.au> wrote:
>>> On 1/04/11 3:29 AM, David Coallier wrote:
>>>>
>>>> Hey there,
>>>>
>>>> I've been working on a little patch that will allow variables ($1) in
>>>> a short-ternary operation to go through an implicit isset
>>>> (zend_do_isset_or_isempty) check so that the average use-case for the
>>>> short-ternary operator doesn't yield in a notice whenever the first
>>>> variable of the expression isn't set.
>>>>
>>>> So the use-case I'm considering is the following:
>>>>
>>>> <?php
>>>> $list = array('name' => 'list');
>>>>
>>>> echo $list['name'] ?: 'List not set.' . PHP_EOL;
>>>> echo $list['name-notset'] ?: 'List not set.' . PHP_EOL;
>>>> ?>
>>>>
>>>> This example, which we all know, will result in a notice for the
>>>> second echo statement because the requested array-key doesn't actually
>>>> exist in the array.
>>>
>>> I'm not familiar with the construct, but to be honest, I fail to see how
>>> it is useful without the suppression of the notice. I mean, it's a
>>> shorthand for isset($var)?$var:$something_else isn't it? That
>>> presupposes that $var may not be set, but that you've accounted for that
>>> fact, so don't want a notice about it. Obviously the isset() can only be
>>> applied if the 'left hand side' is an lval, but I think it makes sense
>>> to apply it whenever it is an lval.
>>>
>>> So a big +1 from me.
>>>
>>> Ben.
>>>
>>
>> Its also a +1 for me, it would make the ternary operator much more
>> useful to me e remove lots of verbose code for handling arrays.
>
> Well, it would change the semantics. And Ben, no, it isn't shorthand for an
> isset() it is like writing (boolean)$var?$var:$something

Thanks for the clarification, Rasmus. That makes sense.

I still think the patch would be very useful, though I can also see how an 
argument could be made for keeping the warning. In my opinion, the case for 
removing the warning is stronger than for keeping it.

Ben.