pp : add one ansi-code function

src/bench/whybench.ml

@@ -377,7 +377,8 @@ let () =
             | Call_provers.Valid -> incr nb_valid
             | _     -> () end
         | _ -> ();
-          Format.printf "\027[0G(%i/%i) valid : %i%!"
+          Format.printf "%a(%i/%i) valid : %i%!"
+            Pp.Ansi.set_column 0
             !nb_done !nb_scheduled !nb_valid
       end;
     Debug.dprintf Scheduler.debug "%s.%s %a %i with %s : %a@."

src/util/pp.ml

@@ -167,3 +167,9 @@ let string_of_wnl p x =
   wnl fmt;
   fprintf fmt "%a@?" p x;
   Buffer.contents b
+
+module Ansi =
+  struct
+
+    let set_column fmt n = fprintf fmt "\027[%iG" n
+end

src/util/pp.mli

@@ -124,3 +124,8 @@ val string_of_wnl : (Format.formatter -> 'a -> unit) -> 'a -> string
   (** same as {!string_of} but without newline *)
 
 val wnl : Format.formatter -> unit
+
+module Ansi :
+sig
+  val set_column : Format.formatter -> int -> unit
+end