SWI Prolog wrap string in newlines

swi_prolog_line_wrap.pl

% wrap_string(+String, +PadLength, -Output) is det.
wrap_string(String, PadLength, Output) :-
  string_length(String, StringLength),
  wrap_string_(String, 0, PadLength, StringLength, "", Output).
wrap_string_(String, PadStart, PadWidth, StrLength, Acc, Output) :-
  NewPadStart is PadStart + PadWidth,
  (   NewPadStart < StrLength
  ->  sub_string(String, PadStart, PadWidth, _, SubString),
      format(string(NewAcc), "~s~s~n", [Acc, SubString]),
      wrap_string_(String, NewPadStart, PadWidth, StrLength, NewAcc, Output)
  ;   sub_string(String, PadStart, _, 0, SubString),
      string_concat(Acc, SubString, Output)
  ).