I found something...

$debug = ($debug eq FALSE) ? TRUE : FALSE;
[download]

But not that it seems THAT much more elegant to me...

Update: Yeah but you all use "0" and "1" instead of "TRUE" and "FALSE". That was not my intention.

Update2: Sorry to stretch that blatant things here, but I feel like like a really novice. So in perl 5.7.1 and 5.6.0 $debug == FALSE always evals to "TRUE", while the ´eq´ operator works ok.

HOWEVER: before I used the use constant FALSE => 0; perl 5.6.0 kept complaining when used "==". No - it´s not too hot here, my computer hasn´t faulty memory nor do have I :-)

Update3: And I hope the last one. First, I would like to thank all of you who responded, you´ve pointed me the right way in a fundamental question I was convinced to know the "truth". Well. I went for the use constant solution. My perhaps nitpicking question is:

use strict;
use constant TRUE  => 1;
use constant FALSE => 0;

(use other Modules)
[download]

use constant TRUE  => 1;
use constant FALSE => 0;
use strict;

(use other Modules)
[download]

The first solution seems consistent, but the second doesn´t have constant definitions spliting up the use field.

Ciao