let rec pp_hum_indent indent ppf = function
| Atom str -> pp_maybe_esc_str ppf str
| List (h :: t) ->
pp_open_box ppf indent;
pp_print_string ppf "(";
pp_hum_indent indent ppf h;
pp_hum_rest indent ppf t
| List [] -> pp_print_string ppf "()"
and pp_hum_rest indent ppf = function
| h :: t ->
pp_print_space ppf ();
pp_hum_indent indent ppf h;
pp_hum_rest indent ppf t
| [] ->
pp_print_string ppf ")";
pp_close_box ppf ()