accessing $this within callback?

I'm using usort() to sort a complex array of arrays. The usort call is
wrapped in a sort method of my own class. The cmp() callback is also a
method of the class. Something like this:

class foo {

function foo() {
$this->thing = array();
$this->bar = 123;
}

function cmp($a, $b) {
print $this->bar; // $this undefined?
}

function sort() {
usort($this->thing, array("foo", "cmp"));
}

}

However, $this seems to be undefined in the cmp() block. Is that just
the way it is? Or is there something I need to do to either expose it,
or call it in a different manner?

TIA,

--cd

Coder Droid wrote:
> However, $this seems to be undefined in the cmp() block. Is that just
> the way it is? Or is there something I need to do to either expose it,
> or call it in a different manner?
>

Change the sort() method into the following:

function sort() {
usort($this->thing, array($this, "cmp"));
}

Also, don't forget to put something in the $thing array; on empty arrays,
the cmp() method will not be called.


JW

> Change the sort() method into the following:
>
> function sort() {
> usort($this->thing, array($this, "cmp"));
> }

Ta da! That was it... thank you. I don't know why I didn't think of
that. Sheesh!

> Also, don't forget to put something in the $thing array; on empty
arrays,
> the cmp() method will not be called.

Of course ... my example was just for illustrative purposes: an array
placeholder to avoid having to type out my complex array just for the
example. I figured $this not existing didn't have anything to with my
array value. (Not that that couldn't have been a bad assumption.)

Again, thanks for pointing out the obvious to me!

--cd