Use finger trees in more places

2 files changed, 3 insertions, 4 deletions

diff --git a/lib/Utilities.ml b/lib/Utilities.ml
index 6f27b30..0472038 100644
--- a/lib/Utilities.ml
+++ b/lib/Utilities.ml
@@ -93,11 +93,9 @@ module FingerTree = struct
         match f elem with None -> acc | Some result -> BatFingerTree.snoc acc result)
       BatFingerTree.empty
 
-  let concat_mapm f xs = BatFingerTree.map f xs |> sequence |> Stdlib.Result.map BatFingerTree.append
-
-  let concat_map f =
-    BatFingerTree.fold_left (fun acc elem -> BatFingerTree.append acc @@ f elem) BatFingerTree.empty
+  let concat xss = BatFingerTree.fold_left BatFingerTree.append BatFingerTree.empty xss
 
+  let concat_mapm f xs = BatFingerTree.map f xs |> sequence |> Stdlib.Result.map concat
 end
 
 module Atomic = struct
diff --git a/lib/Utilities.mli b/lib/Utilities.mli
index 3f0787f..e748693 100644
--- a/lib/Utilities.mli
+++ b/lib/Utilities.mli
@@ -36,6 +36,7 @@ module FingerTree : sig
   val foldm_left : ('a -> 'b -> ('a, 'e) result) -> 'a -> 'b BatFingerTree.t -> ('a, 'e) result
   val join : string BatFingerTree.t -> string -> string
   val filter_map : ('a -> 'b option) -> 'a BatFingerTree.t -> 'b BatFingerTree.t
+  val concat : 'a BatFingerTree.t BatFingerTree.t -> 'a BatFingerTree.t
   val concat_mapm : ('a -> ('b BatFingerTree.t, 'e) result) -> 'a BatFingerTree.t -> ('b BatFingerTree.t, 'e) result
 end