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Date: Fri, 19 Mar 2010 17:21:32 +0100
Message-ID: <660eb66f1003190921g56d47d2cq2c8739433b55f890@mail.gmail.com>
To: "mathieu.suen" <mathieu.suen@easyflirt.com>
Cc: internals@lists.php.net
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Subject: Re: [PHP-DEV] Assign array with __get
From: peter.e.lind@gmail.com (Peter Lind)

Have you considered that perhaps you're trying to use the wrong
language for what you're doing? PHP does what it does now consistently
(in this regard) - what you're suggesting breaks that consistency. To
gain what, exactly?

On 19 March 2010 17:07, mathieu.suen <mathieu.suen@easyflirt.com> wrote:
> Right I could work around the issue with the return by reference without =
any
> problem.
> I am still thinking that if you try to write a meta-circular interpreter =
you
> gonna work very hard
> to make this subtleties worked. And according to "Shriram Krishnamurthi" =
in
> his textbook PLAI:
>
> " a truly powerful language is one that makes it easy to write its
> meta-circular interpreter."
>
> -- Mathieu Suen
>
>
>
> Ionut G. Stan wrote:
>>
>> I guess what Mathieu is trying to say is that this:
>>
>> =C2=A0 =C2=A0class Foo
>> =C2=A0 =C2=A0{
>> =C2=A0 =C2=A0 =C2=A0 =C2=A0public $bar =3D array();
>> =C2=A0 =C2=A0}
>>
>> =C2=A0 =C2=A0$foo =3D new Foo;
>> =C2=A0 =C2=A0$foo->bar[3] =3D 1;
>>
>> =C2=A0 =C2=A0var_dump($foo);
>>
>>
>>
>>
>> ...is inconsistent with this:
>>
>> =C2=A0 =C2=A0class Foo
>> =C2=A0 =C2=A0{
>> =C2=A0 =C2=A0 =C2=A0 =C2=A0public function __get($property)
>> =C2=A0 =C2=A0 =C2=A0 =C2=A0{
>> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0if (! isset($this->$property)) =
{
>> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0$this->$property =
=3D array();
>> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0}
>>
>> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0return $this->$property;
>> =C2=A0 =C2=A0 =C2=A0 =C2=A0}
>> =C2=A0 =C2=A0}
>>
>> =C2=A0 =C2=A0$foo =3D new Foo;
>> =C2=A0 =C2=A0$foo->bar[3] =3D 1;
>>
>> =C2=A0 =C2=A0var_dump($foo);
>>
>>
>>
>>
>> ...or even this:
>>
>> =C2=A0 =C2=A0class Foo
>> =C2=A0 =C2=A0{
>> =C2=A0 =C2=A0 =C2=A0 =C2=A0private $bar =3D array();
>>
>> =C2=A0 =C2=A0 =C2=A0 =C2=A0public function __get($property)
>> =C2=A0 =C2=A0 =C2=A0 =C2=A0{
>> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0return $this->$property;
>> =C2=A0 =C2=A0 =C2=A0 =C2=A0}
>> =C2=A0 =C2=A0}
>>
>> =C2=A0 =C2=A0$foo =3D new Foo;
>> =C2=A0 =C2=A0$foo->bar[3] =3D 1;
>>
>> =C2=A0 =C2=A0var_dump($foo);
>>
>>
>> Now, I'm not really sure this is that bad, as there may be use cases whe=
re
>> one would like to return different values every time __get is called. An=
d,
>> as I wrote in a previous email, there are ways to work around this
>> inconsistency by using return by reference, so everybody can be happy. I
>> think.
>>
>>
>>
>> On 3/19/10 4:56 AM, Etienne Kneuss wrote:
>>>
>>> On Thu, Mar 18, 2010 at 5:47 PM, mathieu.suen
>>> <mathieu.suen@easyflirt.com> =C2=A0wrote:
>>>>
>>>> Peter Lind wrote:
>>>>>
>>>>> On the contrary, it's quite obvious what's going on. In both examples
>>>>> __get() returns an array as PHP would normally do it (i.e. NOT by
>>>>> reference) which means that if you try to modify that you'll end up
>>>>> modifying nothing much. However, in your second example, the point at
>>>>> which you call __get() indirectly comes before the assign to the zork
>>>>> array - hence, the $this->zork['blah'] =3D 'blah'; no longer indirect=
ly
>>>>> calls __get as object::$zork now exists.
>>>>>
>>>>> =C2=A0In other words, this is down to you confusing passing a variabl=
e by
>>>>> reference and passing it by value: PHP normally passes arrays by
>>>>> value, so when __get() returns an array, you're working on a copy of
>>>>> the array you returned. As someone noted earlier, you can easily
>>>>> change the behaviour of __get to return variables by reference, shoul=
d
>>>>> you want to. However, I personally wouldn't want this to be default
>>>>> behaviour as that would make debugging apps much more annoying -
>>>>> things should be consistent, even if consistency at times confuse
>>>>> people.
>>>>>
>>>>> Regards
>>>>> Peter
>>>>>
>>>>>
>>>
>>>
>
>
>
>
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>



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