+let cut prefix s =
+ let lenp = String.length prefix in
+ let lens = String.length s in
+ assert (lens > lenp);
+ assert (String.sub s 0 lenp = prefix);
+ String.sub s lenp (lens-lenp)
+;;
+
+let print_string =
+ let indent = ref 0 in
+ let print_string ~right_justify s =
+ let ss =
+ match right_justify with
+ None -> ""
+ | Some (ss,len_ss) ->
+ let i = 80 - !indent - len_ss - String.length s in
+ if i > 0 then String.make i ' ' ^ ss else ss
+ in
+ assert (!indent >=0);
+ print_string (String.make !indent ' ' ^ s ^ ss) in
+ fun enter ?right_justify s ->
+ if enter then (print_string ~right_justify s; incr indent) else (decr indent; print_string ~right_justify s)
+;;