+ let output_html ?(append_NL = true) html_msg =
+ let rec collect_string = function
+ | `BR -> "\n"
+ | `T s -> s
+ | `L tags -> String.concat "" (List.map collect_string tags)
+ in
+ match html_msg with
+ | `Error msg | `Msg msg ->
+ (if append_NL then prerr_endline else prerr_string)
+ (collect_string msg ^ (if append_NL then "\n" else ""))