Re: [RFC] export TRUE and FALSE from someplace

[muppet <scott asofyet org>]

On Tuesday, January 20, 2004, at 06:49 PM, Jens Luedicke wrote:

> scott asofyet org wrote:
> > i have grown very annoyed of needing to add
> >   use constant TRUE => 1;
> >   use constant FALSE => 0;
> > atop every gtk2-perl program i write.  [..]
>
> Hmm. I'm using 1 and 0 for TRUE and FALSE.
> Is there a special need for those constants?

no technical need.  i prefer them for maintenance.

(i'd stop there, because most of us know what that means, but i'll give 
some examples for those who may be wondering.)

as a contrived example:  at a glance, which of the arguments to 
Gtk2::Box::pack_start is the integer padding value?

  $box->pack_start ($widget1, 0, 0, 0);
  $box->pack_start ($widget2, 1, 1, 1);

it's a lot easier to tell with

  $box->pack_start ($widget, FALSE, FALSE, 0);
  $box->pack_start ($widget, TRUE, TRUE, 1);


more do the point, you may wonder what's magical about returning 1 from 
this closure used as a signal handler, and whether you can return 
positive or negative or even fractional values:

  $window->signal_connect (delete_event => sub { 1 });

but it's obvious here that it returns boolean.

   $window->signal_connect (delete_event => sub { TRUE });

and in this case, returns true to stop event propagation, which keeps 
delete-event from destroying a toplevel window.


--
muppet <scott at asofyet dot org>