package FOO;
sub first {
  print "This is first\n";
}
sub second {
  print "This is second\n";
}
sub dispatch {
  my $self = shift;
  no strict 'refs';
  my $command = shift;
  print "In dispatch, command = $command\n";
  &{$self->{dispatch}{$command}}();

}

sub new {
  my $class = shift;
  my $self = {};
  bless $self, $class;
  $self->{dispatch} = { 'a'=> $self->can('first'), 'b'=> $self->can('second') };
  return $self;
}

package ::;
my $foo = new FOO();
$foo->dispatch('a');
$foo->dispatch('b');

##</code><code>##

$self->$command();