anchor.diff:                                   false ->
                                        [];
                                    _ ->
  -                                     throw({error, lists:flatten(io_lib:format
  -                                                                   ("Condition checking of rule/collector "
  -                                                                    "returns non-boolean value. Template being matched: ~s.",
  -                                                                    [wrangler_prettypr:format(Exp1)]))})
  +                                     throw({error, lists:flatten(
  +                                                     io_lib:format
  +                                                       ("Condition checking of rule/collector "
  +                                                        "returns non-boolean value. Template being matched: ~s.",
  +                                                        [wrangler_prettypr:format(Exp1)]))})
                                end
                        end||{true,Subst}<-Res],
       case lists:append(PossibleMatches) of
  
positive.code:                             [{true, []}];
                         true -> [false]
                      end;
                  _ -> [{true, [{Exp1, Exp2}]}]
  	    end;
  	atom ->
              Exp1Val = wrangler_syntax:atom_value(Exp1),
  
negative.code:             case Rs of 
                  [] ->
                      [{true, E}||{true, E}<-R];
                  _  when R==[]->
                      zip_unification_results(Rs);
                  _ ->
                      [{true, E1++E2}||{true,E1}<-R, 
                                       {true,E2}<-zip_unification_results(Rs)]
  