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References: <4A01A9C3.5010108@smashlabs.com>
	 <e666c3890905060835q50f99e5coaa59ab2158165904@mail.gmail.com>
Date: Thu, 7 May 2009 02:37:43 +0200
Message-ID: <e666c3890905061737y6e8ff5ddhe1aa30e1a5ae4e6e@mail.gmail.com>
To: Ralph Schindler <ralph@smashlabs.com>
Cc: internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] RecursiveFilterItrator possible issues with inheritance
From: webmaster@colder.ch (Etienne Kneuss)

Hello,

On Wed, May 6, 2009 at 5:35 PM, Etienne Kneuss <webmaster@colder.ch> wrote:
> Hello,
>
> On Wed, May 6, 2009 at 5:16 PM, Ralph Schindler <ralph@smashlabs.com> wro=
te:
>> Hi all,
>>
>> I'd like to confirm something as a bug and/or design issue.
>
> This is a bug, could you please report it and assign it to me ?
>
> Thanks,
>
>>
>> Currently, its difficult to extend RecursiveFilterIterator() with additi=
onal
>> __construct() arguments (for configuring its behavior). =A0The reason it=
s
>> difficult is b/c when getChildren() is called, a new instance of the RFI=
 is
>> created (only way you'd know this is if you look into the source of RFI)=
.
>>
>> Ideally, this code would work:
>>
>>
>> $rArray =3D array('a' =3D> array('ab', 'ac', 'ad' =3D> array('ada', 'adc=
')), 'b'
>> =3D> array('bb', 'bc'));
>>
>> $ri =3D new RecursiveArrayIterator($rArray);
>> $filter =3D new MyRFI($ri, 'argument');
>> $iterator =3D new RecursiveIteratorIterator($filter);
>>
>> foreach ($iterator as $key =3D> $item) {
>> =A0 =A0echo $key . ' - ' . $item . PHP_EOL;
>> }
>>
>> class MyRFI extends RecursiveFilterIterator
>> {
>> =A0 =A0protected $_otherArg =3D null;
>>
>> =A0 =A0public function __construct($iterator, $otherArg =3D null)
>> =A0 =A0{
>> =A0 =A0 =A0 =A0$r =3D new ReflectionClass($this);
>> =A0 =A0 =A0 =A0$this->_otherArg =3D $otherArg;
>> =A0 =A0 =A0 =A0parent::__construct($iterator);
>> =A0 =A0}
>>
>> =A0 =A0public function accept()
>> =A0 =A0{
>> =A0 =A0 =A0 =A0echo ($this->_otherArg) ? 'Arg Present' : 'Arg NOT Presen=
t';
>> =A0 =A0 =A0 =A0echo PHP_EOL;
>> =A0 =A0 =A0 =A0return true;
>> =A0 =A0}
>>
>>
>> The current output would be:
>>
>>
>> ~/tmp/test-rii-filter$ php test-rii-problem.php
>> Arg Present
>> Arg NOT Present
>> 0 - ab
>> Arg NOT Present
>> 1 - ac
>> Arg NOT Present
>> Arg NOT Present
>> 0 - ada
>> Arg NOT Present
>> 1 - adc
>> Arg Present
>> Arg NOT Present
>> 0 - bb
>> Arg NOT Present
>> 1 - bc
>>
>>
>> The ideal output would be:
>>
>> Arg Present
>> Arg Present
>> 0 - ab
>> Arg Present
>> 1 - ac
>> Arg Present
>> Arg Present
>> 0 - ada
>> Arg Present
>> 1 - adc
>> Arg Present
>> Arg Present
>> 0 - bb
>> Arg Present
>> 1 - bc
>>
>>
>>
>>
>> The only proposed change I could would be to make the getChildren() insi=
de
>> of RecursiveFilterIterator use clone & add a method called setIterator()
>> instead of Reflection::newInstance($iterator)
>>
>> Is this possible? Or is extending and overriding getChildren() the best
>> strategy here?
>>
>> Reason I post is b/c it seems like using clone/setIterator() would
>> facilitate better inheritance / better polymorphism. =A0And since the
>> implementation is in the extension, the typical developer would generall=
y
>> not understand how getChildren() really works under the hood.

Sorry for the false hope, it is indeed how it's supposed to work and
not a bug. Since the new iterator is instanciated directly inside
getChildren, you can't magically have new arguments to your
constructor and have them filled appropriately.

But you can basically implement all features you want by simply
overriding getChildren.

Clone + setiterator could also work, but changing that would introduce
BC breaks, and I'm not sure it would make more sense than what we have
now.

Regards

>>
>> Thanks,
>> Ralph
>>
>>
>>
>>
>> --
>> PHP Internals - PHP Runtime Development Mailing List
>> To unsubscribe, visit: http://www.php.net/unsub.php
>>
>>
>
>
>
> --
> Etienne Kneuss
> http://www.colder.ch
>
> Men never do evil so completely and cheerfully as
> when they do it from a religious conviction.
> -- Pascal
>



--=20
Etienne Kneuss
http://www.colder.ch

Men never do evil so completely and cheerfully as
when they do it from a religious conviction.
-- Pascal