pp: expose fill and and fill_map

src/pp/containers_pp.ml

@@ -358,6 +358,8 @@ let fill sep = function
     in
     { view = Fill { sep; l }; wfl }
 
+let fill_map sep f l = fill sep (List.map f l)
+
 let of_list ?(sep = nil) f l =
   let rec loop = function
     | [] -> nil

src/pp/containers_pp.mli

@@ -55,6 +55,12 @@ val newline : t
 val nl : t
 (** Alias for {!newline} *)
 
+val fill : t -> t list -> t
+(** [fill sep l] resembles [group (append_l ~sep l)], except it tries
+    to put as many items of [l] as possible on each line.
+
+    In terms of {!Format}, this is like the hov box. *)
+
 (** {2 Output device} *)
 
 (** Arbitrary output.
@@ -167,6 +173,9 @@ val append_sp : t list -> t
 val append_nl : t list -> t
 (** Same as {!append_l} with [sep=nl] *)
 
+val fill_map : t -> ('a -> t) -> 'a list -> t
+(** [fill_map sep f l] is [fill sep (List.map f l)] *)
+
 val bool : bool -> t
 val int : int -> t
 val float : float -> t