use Tk;
$mw = new MainWindow(-title=>'mapp');
$pg = $mw->Frame;

@map_fields = \(qw( A B C D E ));
$cnt2 = 0;
@file_fieldnames =  qw( SHOW COLUMNS FROM lead SKIP );
  
foreach my $field ( @file_fieldnames ) 
{
   $pg->Label(-relief => 'sunken', -width => 15, -text => $field)->pack();
   my $brb = $pg->BrowseEntry(-variable => ($map_fields[$cnt2]) );
   $brb->insert('end', @$dbfields);
   $cnt2++;
   $brb->pack();
}

my $btn =$pg->Button(-text=>'doit', -command => sub { doit() } );
$btn->pack;
$pg->pack();

MainLoop;

sub doit 
{
	$ifg->{parameter} = '1,2,3,4,5';
	my @a = ( split ( ",", $ifg->{parameter} ) );
	for ( @map_fields ) { $$_ = shift @a } ;
}