{
   my @new = ();
   my $in = sub {
     for(@array,@new){ return 1 if $_ eq $_[0] } return 0
   };
   local $_;
   while( @array ){
      $_ = shift @array;

      #this is of course pseufo for really figuring out
      # a new value
      my $new = shift @figure_out or next;

      $in->($new) or
             push @array,$new;

   } continue {
      push @new,$_
   }

   @array = @new;
}