package Track;
our %switch = (); # to be filled in by subclasses.
sub new { 
   my ($class) = @_; # don't have any args in mind yet.
   my $this = bless({}, $class); 
   return $this->init(); 
} 
sub move { AbstractMethod->throw("Not implemented in this class\n"); } # raise exception unless 
																	# implemented by a subclass

package BasicTrack;
use base Track;
sub init {
    my ($this) = @_; 

    # Add anonymous subroutines to the hash of possible combinations
    # of status and location. I.e., if the status is 'pending
    # approval' while the document is sitting in the workspace of a
    # supervisor, and 'forward' is the command issued to Track::move,
    # then the subroutine ought to set the status to 'approved',
    # change group to 'editors'. Other subclasses can inherit
	# or override these as necessary, to avoid duplication of behavior.

    $Track::switch{case1} = sub { # do the stuff };
}

sub move {
	my ($this, $arg) = @_;
	# complicated set of switch statements to figure 
	# out which subroutine in %Track::switch to call.
	# This would be called from Ticket::move most likely.
}