diff --git a/lib/Block.ml b/lib/Block.ml
index dac57ca..f8cd17a 100644
--- a/lib/Block.ml
+++ b/lib/Block.ml
@@ -1,43 +1,40 @@
 type 'a t = Common of 'a | Changed of { mine : 'a list; their : 'a list }
 
 let of_hunk (hunk : 'a Patch.hunk) : 'a t list =
-  let rec process_hunk acc current_mine current_their = function
+  let rec aux acc current_mine current_their lines =
+    match lines with
     | [] ->
         if current_mine <> [] || current_their <> [] then
-          Changed
-            { mine = List.rev current_mine; their = List.rev current_their }
-          :: acc
+          Changed { mine = current_mine; their = current_their } :: acc
         else acc
     | `Common line :: rest ->
         let acc' =
           if current_mine <> [] || current_their <> [] then
-            Changed
-              { mine = List.rev current_mine; their = List.rev current_their }
-            :: acc
+            Changed { mine = current_mine; their = current_their } :: acc
           else acc
         in
-        process_hunk (Common line :: acc') [] [] rest
-    | `Mine line :: rest ->
-        process_hunk acc (line :: current_mine) current_their rest
-    | `Their line :: rest ->
-        process_hunk acc current_mine (line :: current_their) rest
+        aux (Common line :: acc') [] [] rest
+    | `Mine line :: rest -> aux acc (line :: current_mine) current_their rest
+    | `Their line :: rest -> aux acc current_mine (line :: current_their) rest
   in
-  List.rev (process_hunk [] [] [] hunk.lines)
+  List.rev (aux [] [] [] hunk.lines)
 
 let to_hunk (blocks : 'a t list) : 'a Patch.hunk =
-  let lines, mine_len, their_len =
-    List.fold_left
-      (fun (lines, mine_len, their_len) block ->
-        match block with
-        | Common line -> (`Common line :: lines, mine_len + 1, their_len + 1)
-        | Changed { mine; their } ->
-            let mine_lines = List.map (fun line -> `Mine line) mine in
-            let their_lines = List.map (fun line -> `Their line) their in
-            ( mine_lines @ their_lines @ lines,
-              mine_len + List.length mine,
-              their_len + List.length their ))
-      ([], 0, 0) blocks
+  let rec aux lines mine_len their_len blocks =
+    match blocks with
+    | [] -> (lines, mine_len, their_len)
+    | Common line :: rest ->
+        aux (`Common line :: lines) (mine_len + 1) (their_len + 1) rest
+    | Changed { mine; their } :: rest ->
+        let mine_lines = List.map (fun line -> `Mine line) mine in
+        let their_lines = List.map (fun line -> `Their line) their in
+        aux
+          (mine_lines @ their_lines @ lines)
+          (mine_len + List.length mine)
+          (their_len + List.length their)
+          rest
   in
+  let lines, mine_len, their_len = aux [] 0 0 blocks in
   {
     mine_start = 0;
     mine_len;