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Date: Tue, 9 Aug 2005 14:02:58 -0400
To: Andi Gutmans <andi@zend.com>
Cc: Pierre-Alain Joye <pierre@dotgeek.org>, internals@lists.php.net
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Subject: Re: [PHP-DEV] Re: RC1, instanceof?
From: kingwez@gmail.com (Wez Furlong)

Maybe a little late throwing my 2 cents in, but here they are anyway.
If you're writing an app that can optionally use a component that is
not present, there is nothing conceptually wrong with calling
instanceof to determine if that support is present; PHP should not
blow up.  If the class is not loaded, then the object can't possibly
be an instance of it, therefore the operator should return false.

--Wez.

On 8/9/05, Andi Gutmans <andi@zend.com> wrote:
> You are wrong because __autoload() *is* called and you can load the class
> on the-fly. The only problem is if the class does not exist in your code
> base, in which case, your application should blow up!
>=20
> Andi
>=20
> At 07:44 AM 8/9/2005 +0200, Pierre-Alain Joye wrote:
> >On Mon, 08 Aug 2005 14:43:25 -0700
> >andi@zend.com (Andi Gutmans) wrote:
> >
> > > I don't agree that instanceof on a class which doesn't exist
> > > should work. It doesn't do so in other languages (or at least not
> > > in Java/C++(dynamic_cast)) nor does it really seem to make a lot
> > > of sense and be useful. Sounds more like an edge case you have
> > > hit with some weird code which can probably be written
> > > differently.
> >
> >You cannot compare PHP with Java and C++ in this case, sorry. They
> >work differently for known reason (compiled being one).
> >
> >If you have a method, which could be a factory, or the behaviors
> >depends on which object it gets, you have now 2 choices:
> >
> >- Accept to live with a possible fatal error
> >
> >- Include all single classes you are going to check, even if you
> >   will use none of them.
> >
> >The 3rd possibility, fix instanceof.
> >
> > > Today, fetching of classes in the language is very generic, and
> > > they have to exist. I see very few cases where this would not be
> > > true if you are writing a regular application. In those few cases
> > > where you are doing something extremely weird, you can use
> > > reflection to introspect an object.
> >
> >Agreed, that's fetch_class is not opportun for instanceof. My point
> >is not about the fetch_class is done but the way instanceof works.
> >Reflection is terribly overkilled for such a need, and slow.
> >
> > > There is no way this would be changed for RC1 (or PHP 5.1)
> > > because it's a significant change which would affect many places
> > > and not only instanceof. I personally think it shouldn't be
> > > changed at all. If you're referencing classes/exceptions in your
> > > code that don't exist, then something is very bogus with your
> > > code. Don't use a NonExistantException if that could happen, use
> > > Exception...
> >
> >Agreed here too, not related to instanceof though.
> >
> >
> >--Pierre
> >
> >--
> >PHP Internals - PHP Runtime Development Mailing List
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