anchor.diff:  
       %% Return an iterator function. Returns
       %% a new result.
  -    fun() -> 
  -            it_op_inner(Pid, Ref, Op)
  -    end.
  +    fun() -> it_op_inner(Pid, Ref, Op) end.
   
   %% @private Holds the function body of a leaf-iterator. When called,
   %% it requests the next result from the mailbox, and serves it up
  
positive.code: it_combine_inner(SelectFun, [IteratorA,IteratorB|Rest]) ->
      Iterator = fun() -> SelectFun(IteratorA(), IteratorB()) end,
      [Iterator|it_combine_inner(SelectFun, Rest)].
      
  %% @private Chain an operator, and build an iterator function around
  %% it. The iterator will return {Result, NotFlag, NewIteratorFun} each
  %% time it is called, or block until one is available. When there are
  
negative.code: it_op(Op, SearchState) ->
      %% Spawn a collection process...
      Ref = make_ref(),
      F = fun() ->
                  Parent = SearchState#search_state.parent,
                  erlang:link(Parent),
                  erlang:process_flag(trap_exit, true),
                  it_op_collector_loop(Parent, Ref, [])
          end,
      Pid = erlang:spawn_link(F),
  
  