Cleanup, reduce Lwd.set calls

prompt.ml

@@ -64,7 +64,9 @@ module User_prompt = struct
     let text, position =
       Utils.render_cursor ~width:(max 0 (w - 3)) state.cursor
     in
-    Lwd.set cursor (position + 1, y);
+    let new_cursor = (position + 1, y) in
+    if new_cursor <> (Lwd.peek cursor) then
+      Lwd.set cursor new_cursor;
     I.hcat [ I.char A.empty ' ' 1 1 ; text ]
 end
 
@@ -116,7 +118,10 @@ let make ~quit ~message cursor =
   let ( and+ ) = Lwd.map2 ~f:(fun x y -> (x, y)) in
   let state = Lwd.var (make quit message) in
   let position = Lwd.var (0, 0) in
-  let hook = Lwd.set state in
+  let hook state' =
+    if (Lwd.peek state).cursor != state'.cursor then
+      Lwd.set state state'
+  in
   let update_prompt state (y, w) =
     let user = User_prompt.render ~cursor ~y ~w state in
     Ui.keyboard_area (handler ~hook state) (Ui.atom user)

window.ml

@@ -51,27 +51,22 @@ let render { w; h } msgs =
   done;
   Ui.atom (I.vsnap ~align:`Bottom h !image)
 
-let handler ~hook:_ _state _buffer _key = `Unhandled
-
 let make w =
   let ( let* ) x f = Lwd.bind ~f x in
   let ( let+ ) x f = Lwd.map ~f x in
   let ( and+ ) = Lwd.map2 ~f:(fun x y -> (x, y)) in
 
-  let state = Lwd.var { w = 0; h = 0; p = 0 } in
-  let hook = Lwd.set state in
+  let state = Lwd.var { w = 0; h = 0 } in
 
   let* document =
     let+ state = Lwd.get state
     and+ buffer = Lwd.get w in
-    Ui.keyboard_area
-      (handler ~hook state buffer)
-      (render state buffer)
+    render state buffer
   in
 
   let update_size ~w ~h =
     let state' = Lwd.peek state in
-    if state'.w <> w || state'.h <> h then Lwd.set state { state' with w; h }
+    if state'.w <> w || state'.h <> h then Lwd.set state { w; h }
   in
 
   let measure_size document =