RE: [PHP] PHP5 - instanceof [SOLVED]

From: Date: Thu, 13 May 2004 04:47:33 +0000
Subject: RE: [PHP] PHP5 - instanceof [SOLVED]
Groups: php.general 
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ah yes, of course "instanceof" means you're working with an instance of an class - <slaps forehead> Pity there's no equivalent for classes :( oh well, I'll just have instantiate the class first then do the checking. Thanks Martin > -----Original Message----- > From: Travis Low [mailto:travis@dawnstar.com] > Sent: Thursday, 13 May 2004 2:42 PM > To: php-general@lists.php.net > Subject: Re: [PHP] PHP5 - instanceof > > > An instance only exists after it has been instantiated. So > you can't know > anything about an instance (== an object) beforehand. It's > like knowing a > person before they are born. > > Maybe you mean you want to determine if class B is a subclass > of class A. > That's the same problem again. Even if PHP5 had a Class > object (a la Java), > you'd have to instantiate *it* in order to find the > relationship between class > A and class B. Prior to that point, you only have text > strings to work with. > I suppose you could search the text of the file for "extends > FooBar" or something. > > cheers, > > Travis > > Martin Towell wrote: > > I have been playing with PHP5 and am liking it more and > more. But I have one > > question about "instanceof" > > > > If you have something like this: > > > > <? > > class A { } > > class B extends A { } > > $x = new B; > > if ($x instanceof B) echo "B"; > > if ($x instanceof A) echo "A"; > > ?> > > > > This would echo "BA". That's good, I understand that. > > > > Now the question: Is it possible to determine if B is an > instance of A > > without instantiating it? > > > > Thanks > > Martin > > > > -- > Travis Low

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