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Date: Sat, 03 Jun 2006 10:11:58 -0700
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To: Marcus Boerger <helly@php.net>
CC: Ilia Alshanetsky <ilia@prohost.org>, internals@lists.php.net,
	Dmitry Stogov <dmitry@zend.com>, Andi Gutmans <andi@zend.com>,
	Zeev Suraski <zeev@zend.com>
References: <795156743.20060603134212@marcus-boerger.de> <18CE805D-C032-4B64-950A-119E46287AF5@prohost.org> <4481B92E.2030802@lerdorf.com> <1895425731.20060603184326@marcus-boerger.de>
In-Reply-To: <1895425731.20060603184326@marcus-boerger.de>
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Subject: Re: [PHP-DEV] Missing __toString() part
From: rasmus@lerdorf.com (Rasmus Lerdorf)

Right, just let me clarify.  My point here was that if we are going to 
make a change here, we should do it correctly and come up with a way to 
create a unique hash of the object so it really can be used as an array 
index.  Magically calling __toString() in a case where we don't have an 
explicit string context sounds half-assed and non-obvious to me.  If you 
want that ability, simply do: $a[(string)$obj] and it is obvious what 
you are doing.

-Rasmus

Marcus Boerger wrote:
> Hello Rasmus,
> 
>   though you are probably right here your idea brought to it's full
> extend will bring a major BC break. Just consider we had both key
> and value as a zval then the current behavior would change for quite
> a lot of situations including not only objects and resources but also
> booleans, floats and NULL.
> 
> Right now everybody is used to the restiction that an array key can
> only be a string or an integer and if not it is either not acceptable
> as a key at all or is being converted to either one.
> 
> best regards
> marcus
> 
> Saturday, June 3, 2006, 6:30:38 PM, you wrote:
> 
>> I don't understand why using the object as an index would trigger a 
>> __toString() call.  PHP's array indices are not defined to be strings, 
>> so I don't see this as being a string context use and thus __toString() 
>> shouldn't be called.
> 
>> I also don't see why we need to make a distinction between the key and 
>> the value here if there is any way we can avoid it.
> 
>> For example, this obviously works:
> 
>>    class foo {
>>      function a() { echo "a"; }
>>    }
>>    $a = new foo();
>>    $b[1] = $a;
>>    $b[1]->a();
> 
>> Why shouldn't this?
> 
>>    $b[$a] = 1;
>>    key($b)->a();
> 
>> I have always looked a PHP array as having 2 places to store things. 
>> You can store stuff in the key with the caveat/feature that it must be 
>> unique and you can store whatever you want in the value part.  Only 
>> allowing strings and integers in the key seems like an arbitrary 
>> restriction to me.  As long as the key is something we can somehow 
>> uniquely identify I think we should aim to support it.
> 
>> -Rasmus
> 
>> Ilia Alshanetsky wrote:
>>> I think this is a potentially missing bit of functionality we definitely 
>>> need to consider including. There is really no technical reason why 
>>> $foo[new ToStringObject] = "bar"; cannot work or a reason why it 
>>> shouldn't as far as functionality goes.
>>>
>>>
>>> Ilia Alshanetsky
>>>
>>>
>>>
>>>
>>> On 3-Jun-06, at 7:42 AM, Marcus Boerger wrote:
>>>
>>>> Hello guys,
>>>>
>>>>   the attached patch closes one more __toString() part. It allows
>>>> to use objects that define __toString as indexes to arrays. What do
>>>> you guys think about this, should we add it or stay with the old
>>>> behavior that didn't allow objects as indexes at all.
>>>>
>>>> --Best regards,
>>>>  Marcus                          mailto:mail@marcus-boerger.de
>>>> <ze2-offset-obj-tostring-20060603.diff.txt>
>>>> --PHP Internals - PHP Runtime Development Mailing List
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> 
> 
> 
> 
> Best regards,
>  Marcus