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Date: Wed, 2 May 2012 07:37:34 -0400
Message-ID: <CAAyV7nGi6EvEf_tjFp_chn771+5cn-Lqt6mQSDQn2fD61nsAiw@mail.gmail.com>
To: Pierre Joye <pierre.php@gmail.com>
Cc: Ferenc Kovacs <tyra3l@gmail.com>, Laruence <laruence@php.net>, 
	Patrick ALLAERT <patrickallaert@php.net>, Nikita Popov <nikita.ppv@googlemail.com>, 
	PHP internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] [RFC] Allow non-variable arguments to empty() and isset()
From: ircmaxell@gmail.com (Anthony Ferrara)

Pierre,

On Wed, May 2, 2012 at 5:43 AM, Pierre Joye <pierre.php@gmail.com> wrote:
> hi,
>
> On Wed, May 2, 2012 at 11:36 AM, Ferenc Kovacs <tyra3l@gmail.com> wrote:
>
>> $foo=3Dnull;
>> var_dump(isset($foo)); //prints=A0bool(false)
>
> No offset meant, but it is totally expected and well known, and as far
> as I remember documented too. Assigning NULL to a variable unsets it
> (so to say).

Well, except that it doesn't unset it.  It only fails isset().  The
symbol still exists in the symbol table, and the zval is still
allocated.  That's one reason that isset() can return false, and
array_key_exists() will return true.  But right now there's no way to
check if a symbol exists since isset returns falls for a null value in
a symbol (and there's no other way to check it)...

Not saying it should change, just that it's a corner case that's not
accounted for in the API...

I voted for the ability to use an expression for isset() as well,
since I agree with Ferenc, it's a matter of consistency.  Sure, the
use-case for isset() is definitely weaker than for empty(), but at the
same token they are definitely related...

Anthony

>>> empty() on the other hand, tests if something is empty, and only if it
>>> is empty. The result of an expression can be empty.
>>>
>>
>> an expression can also have a value of null.
>
> And NULL is empty. No issue here.
>
> Cheers,
> --
> Pierre
>
> @pierrejoye | http://blog.thepimp.net | http://www.libgd.org
>
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