anchor.diff:    {[$! | Acc], T, Length + 1, [$! | Special]};
   tokenize_continue([$? | T], Acc, Length, Special) ->
     {[$? | Acc], T, Length + 1, [$? | Special]};
  -tokenize_continue([H | T], Acc, Length, Special) when ?is_upcase(H); ?is_downcase(H); ?is_digit(H); H == $_ ->
  +tokenize_continue([H | T], Acc, Length, Special) when ?is_upcase(H); ?is_downcase(H); ?is_digit(H); H =:= $_ ->
     tokenize_continue(T, [H | Acc], Length + 1, Special);
   tokenize_continue(Rest, Acc, Length, Special) ->
     {Acc, Rest, Length, Special}.
  
positive.code: handle_space_sensitive_tokens([Sign, NotMarker | T], Line, Column, Scope, [{Identifier, _, _} = H | Tokens]) when
      ?dual_op(Sign),
      not(?is_space(NotMarker)),
      NotMarker /= $(, NotMarker /= $[, NotMarker /= $<, NotMarker /= ${,                  %% containers
      NotMarker /= $%, NotMarker /= $+, NotMarker /= $-, NotMarker /= $/, NotMarker /= $>, %% operators
      Identifier == identifier ->
    Rest = [NotMarker | T],
    DualOpToken = {dual_op, {Line, Column, nil}, list_to_atom([Sign])},
  
negative.code:     end,
  
    case lists:last(Identifier) of
      Last when Last =:= $!; Last =:= $? ->
        Msg = io_lib:format("found ~ts \"~ts\", ending with \"~ts\", followed by =. "
                            "It is unclear if you mean \"~ts ~ts=\" or \"~ts =\". Please add "
                            "a space before or after ~ts to remove the ambiguity",
  