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Date: Mon, 04 Oct 2004 13:01:56 +0100
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Subject: Static call detection
From: marcus@synchromedia.co.uk (Marcus Bointon)

How can you find out definitively if a method of a PHP class has been called
statically, in both PHP 4 and 5? I'm aware of the way that $this behaves  -
this is not that old FAQ, but it's at the root of the problem. I can't find
a straight answer - even an "it's not possible" would be more helpful.

Just to illustrate:

Class a {
  function foo(){
    print "foo";
  }
  function spanner() {
    a::foo();
  }
}
Class b {
  function bar() {
    print "bar";
  }
  function foobar() {
    a::foo();
  }
  function foobar2() {
    $a = new a;
    $a->foo();
  }
}

$a = new a;
$b = new b;
$a->foo(); //dynamic
$b->bar(); //dynamic
a::foo(); //static, $this undefined
b::bar(); //static, $this undefined
$b->foobar(); //statically calls a::foo()
$b->foobar2(); //Dynamically calls a::foo()
$a->spanner(); //Static call from an instance of itself

The problem is in detecting the last 3 call types correctly. You can't look
at $this because it can't tell you anything useful about the call's context,
unless it's undefined, in which case you know for sure that the call is
static. Is_a() etc seem to be no use, as $this. It seems that there would be
a place for an additional predefined variable like $me or something that
does contain the current instance, if any, and avoids the transitive nature
of $this.

I've asked this a couple of times on the general list, plus several forums,
and aside from the usual pointers to the $this faq, no solution has been
suggested, so I'm asking here.

This has been bugging me for ages, and I've been resorting to param counting
to work around it for now - is there a better way?

Marcus
-- 
Marcus Bointon
Synchromedia Limited: Putting you in the picture
marcus@synchromedia.co.uk | http://www.synchromedia.co.uk