[perl-win32-gui-hackers] Mini update to Hook()

[Stephen P. <Ste...@uc...>]

Hi,

Just thought I'd add a little something to the HEM =
(Hacker/Horrible/Hotchpotch Event Model). $win->Hook() now returns the =
previous coderef if you reassign a hook. For instance:

my $hookone =3D $win->Hook(0x0020, \&setcursor);
my $hooktwo =3D $win->Hook(0x0020, \&somethingelse);

$hookone now equals 0 (no previous reference).
$hooktwo is now a reference to &setcursor (the hook handler that was =
replaced by \&somethingelse).

You can't assign more than one handler to a message, since the message =
identifies the handler to call on a key/value basis (just a perl list).

The function still returns undef if you passed it invalid arguments, so =
error handling is a breeze:

if( defined($hookone) ) {
	if( ref($hookone) ) {
		print "Previous reference re-defined\n";
	}
	else {
		print "This is the first hook we've made for this message\n";
	}
}
else {
	print "We passed dumb arguments.\n";
}

It's in the CVS now. Hopefully this will make things more useful, and =
allows you to create modules that "grab" hooks but still honour any =
hooks that the user of your module has previously defined.

Steve