TK param passing

[jsteng]

I would see codes written like this:

$submit->bind('<1>' => sub { Submit($p1, $p2, $p3, $p4, $p5); } );

The above codes I understand, knowing how many parameters and how to intercept the params in a subroutine.



However I dont understand this code:

$yscroll=$mw->Scrollbar()->pack(-fill=>'y', -side=>'right',);
$yscroll->configure( -command => [ \&ScrollAll, $yscroll, [$p1, $p2, $
+p3, $p4, $p5]]);
sub ScrollAll {
    my ($sb, $wigs, @args) = @_;
        foreach my $w (@$wigs) {
            $w->yview(@args);
        }
}

Can anyone explain how the params are passed when it is constructed in this manner:
-command => [ \&ScrollAll, $yscroll, [$p1, $p2, $p3, $p4, $p5]]
In the above sub's code my ($sb, $wigs, @args) = @_;
What is assigned to $sb?
What is assigned to $wigs?
Is there any other way of passing params when used with -command?
And can that like be written like:

-command => sub {
    subname ($p1, $p2, $p3, $p4, $p5); 
}

thanks

[Discipulus]

Hello jsteng,

When you specify a callback (this is the magic word to search for) for a Tk action and this callback need arguments you need to pass an anonymous array with the function and it's arguments

-command => [ \&subname, arg1, arg2 ... ]

See it explained in it's own doc: Tk::callbacks

In your example, if I understand it correctly $yscroll arrives as $b in the sub and the anonymous array [$p1, $p2, $p3, $p4, $p5] arrives as $wigs in the sub.

Anyway, as AnonymousMonk telegraphically stated, use Data::Dump and it's dd method to dump what @_ is inside of your sub.

L*

[Anonymous Monk]

Try It To See?