anchor.diff:  %% XXX badly chosen function name - I mostly associate this name with
   %% functions like lists:append - hsten
   %%--------------------------------------------------------------------
  -join([], Separator) ->
  +join([], _Separator) ->
       [];
  -join([A], Separator) ->
  +join([A], _Separator) ->
       A;
   join([String | Rest], Separator) ->
       String ++ Separator ++ join(Rest, Separator).
  
positive.code: %% XXX badly chosen function name - I mostly associate this name with
  %% functions that add a element to a list - hsten
  %%--------------------------------------------------------------------
  concat([], Separator) ->
      [];
  concat([A | B], Separator) ->
      A ++ Separator ++ concat(B, Separator).
  
negative.code: %% Function:
  %% Descrip.: ???
  %% Returns :
  apply_rewrite([], _List) ->
      [];
  apply_rewrite([$\\, $\\ | Rest], List) ->
      [$\\ | apply_rewrite(Rest, List)];
  