added some lwd, not sure it's useful yet

dune

@@ -28,6 +28,7 @@
    irmin-git
    compiler-libs.toplevel
    re
+   lwd
  )
  (link_flags (-linkall))
   (ocamlopt_flags (:standard -O3 -unboxed-types))

ogui.ml

@@ -5,7 +5,6 @@ module Str = Re.Str
 
 type stroke = { width : float; color : Gv.Color.t }
 
-let debuglayout = ref false
 let stroke_none = { width = 0.; color = Gv.Color.transparent }
 
 let pp_text_row : Gv.Text.text_row F.t =
@@ -91,11 +90,25 @@ module TextBuffer = struct
     mutable path : string list;
     mutable tree : Store.S.tree;
     repo : Store.Sync.db Lwt.t;
+    var : string Lwd.var;
   }
 
-  let of_repo ~path ~(repo : Store.Sync.db Lwt.t) =
+  let of_repo ~path ~(repo : Store.Sync.db Lwt.t) : t Lwt.t =
     let tree = Lwt_main.run (repo >>= Store.S.tree) in
-    { path; tree; repo }
+    Store.S.Tree.find tree path >>= fun res ->
+    Lwt.return
+      {
+        path;
+        tree;
+        repo;
+        var =
+          Lwd.var
+            (match res with
+            | Some s -> s
+            | None ->
+                F.epr "TextBuffer.of_repo: None@.";
+                "");
+      }
 
   let of_string ~path ?(repo = None) str =
     {
@@ -104,13 +117,13 @@ module TextBuffer = struct
       repo =
         ( Store.S.Repo.v (Irmin_mem.config ()) >>= fun repo' ->
           Option.value ~default:Store.S.(empty repo') repo );
+      var = Lwd.var str;
     }
 
   let insert_uchar t n uc : t Lwt.t =
-    F.epr "TextBuffer.insert_uchar %d %a@." n pp_uchar uc;
-
+    (* F.epr "TextBuffer.insert_uchar %d %a@." n pp_uchar uc; *)
     match t with
-    | { path; tree; _ } as tt ->
+    | { path; tree; var; _ } as tt ->
         Store.S.Tree.update tree path (function
           | Some src ->
               let sn = String.length src in
@@ -126,15 +139,16 @@ module TextBuffer = struct
                 BytesLabels.blit_string ~src ~src_pos:n ~dst
                   ~dst_pos:(n + uclen)
                   ~len:(sn - (n + uclen));
-              Some (Bytes.to_string dst)
+              Lwd.set var (Bytes.to_string dst);
+              Some (Lwd.peek var)
           | None -> None)
         >>= fun tree -> Lwt.return { tt with tree }
 
   let remove t (a, b) : t Lwt.t =
     let a, b = (min a b, max a b) in
-    F.epr "TextBuffer.remove (%d, %d)@." a b;
+    (* F.epr "TextBuffer.remove (%d, %d)@." a b; *)
     match t with
-    | { path; tree; _ } as tt ->
+    | { path; tree; var; _ } as tt ->
         Store.S.Tree.update tree path (function
           | Some src ->
               let srcn = String.length src in
@@ -142,14 +156,15 @@ module TextBuffer = struct
               let dst = Bytes.create (srcn - (b - a)) in
               Bytes.blit_string src 0 dst 0 a;
               Bytes.blit_string src b dst a (srcn - b);
+              Lwd.set var (Bytes.to_string dst);
               Some (Bytes.to_string dst)
           | v -> v)
         >>= fun tree -> Lwt.return { tt with tree }
 
   let remove_uchar t n : t Lwt.t =
-    F.epr "TextBuffer.remove_subset n=%d @." n;
+    (* F.epr "TextBuffer.remove_subset n=%d @." n; *)
     match t with
-    | { path; tree; _ } as tt ->
+    | { path; tree; var; _ } as tt ->
         Store.S.Tree.update tree path (function
           | Some src ->
               let srcn = String.length src in
@@ -160,8 +175,11 @@ module TextBuffer = struct
               let dst = Bytes.create (srcn - ucn) in
               Bytes.blit_string src 0 dst 0 n;
               Bytes.blit_string src (n + ucn) dst n (srcn - n - ucn);
+              Lwd.set var (Bytes.to_string dst);
               Some (Bytes.to_string dst)
-          | v -> v)
+          | None ->
+              F.epr "TextBuffer.remove_uchar None";
+              None)
         >>= fun tree -> Lwt.return { tt with tree }
 
   let fold_string t (f : string -> 'a) : 'a Lwt.t =
@@ -169,6 +187,8 @@ module TextBuffer = struct
     | { path; tree; _ } ->
         Store.S.Tree.get tree path >>= fun text -> Lwt.return (f text)
 
+  let get t = Lwd.get t.var
+
   let contents { path; tree; _ } =
     (try Store.S.Tree.get tree path with
     | Not_found | Invalid_argument _ ->
@@ -504,19 +524,16 @@ module TextLayout = struct
         ])
 
   let cursor_default = { index = 0; last_col = 0 }
+  let cursor ?(last_col = 0) index : cursor = { index; last_col }
 
-  let cursor ?(last_col = 0) index : cursor =
-    F.epr "cursor last_col=%d index=%d@." last_col index;
-    { index; last_col }
-
-  let simple text ?(start = 0) ?(format = format_default) wrap_width :
-      layout Lwt.t =
-    TextBuffer.fold_string text (fun s ->
+  let simple (text : 'a) ?(start = Lwd.pure 0)
+      ?(format = format_default) wrap_width : layout Lwd.t =
+    Lwd.map2 (TextBuffer.get text) start ~f:(fun str start ->
         {
           layout_default with
           text;
           sections =
-            [ { byte_range = (start, String.length s); format } ];
+            [ { byte_range = (start, String.length str); format } ];
           wrap =
             { (default_text_wrapping ()) with max_width = wrap_width };
         })
@@ -537,10 +554,6 @@ module TextLayout = struct
         List.fold_left
           (fun (l : section list) sec ->
             let s, e = sec.byte_range in
-            if !debuglayout then
-              F.epr "with_range section cs=%d ce=%d s=%d e=%d@." cs ce
-                s e;
-
             l
             @ (if
                  e < cs || ce < s
@@ -571,21 +584,19 @@ module TextLayout = struct
           [] layout.sections;
     }
 
-  let with_cursor (cur : cursor) ?(format = default_cursor_formatter)
-      layout : layout =
-    let c = with_range (cur.index, cur.index + 1) ~format layout in
-    if !debuglayout then
-      F.epr "with_cursor %a@."
-        F.(brackets @@ list ~sep:cut pp_section)
-        c.sections;
-    c
+  let with_cursor (cursor : cursor Lwd.t)
+      ?(format = default_cursor_formatter) layout : layout Lwd.t =
+    Lwd.map2 cursor layout ~f:(fun c l ->
+        with_range (c.index, c.index + 1) ~format l)
 
-  let with_mark (mark : int option) (cur : int)
-      ?(format = default_mark_formatter) layout : layout =
-    match mark with
-    | Some mark' ->
-        with_range ~format (min mark' cur, max mark' cur) layout
-    | None -> layout
+  let with_mark (mark : int option Lwd.t) (cursor : cursor Lwd.t)
+      ?(format = default_mark_formatter) layout : layout Lwd.t =
+    Lwd.bind layout ~f:(fun l ->
+        Lwd.map2 mark cursor ~f:(fun m c ->
+            match m with
+            | Some m' ->
+                with_range ~format (min m' c.index, max m' c.index) l
+            | None -> l))
 end
 
 let rec nth_tl n = function
@@ -594,11 +605,11 @@ let rec nth_tl n = function
 
 module Ui = struct
   type t = {
-    mutable rect : Gg.box2;
+    rect : Gg.box2 Lwd.var;
     enabled : bool;
     gv : Gv.t;
     glfw_window : GLFW.window option;
-    mutable bindings : action list Event.t;
+    bindings : action list Event.t Lwd.var;
   }
 
   and action = Custom of (unit -> unit Lwt.t)
@@ -611,7 +622,7 @@ module Ui = struct
       enabled = true;
       gv;
       glfw_window = window;
-      bindings = Event.empty;
+      bindings = Lwd.var Event.empty;
     }
 
   let callback_resolver : action list Event.resolver option ref =
@@ -622,12 +633,18 @@ module Ui = struct
     let res =
       match !callback_resolver with
       | Some res -> res
-      | None -> Event.resolver [ Event.pack Fun.id t.bindings ]
+      | None ->
+          Event.resolver
+            [
+              Event.pack Fun.id
+                (t.bindings |> Lwd.get |> Lwd.observe
+               |> Lwd.quick_sample);
+            ]
     in
 
-    Event.(
+    (*Event.(
       F.epr "Ui.keycallback %a %a %a@." pp_key key pp_key_action state
-        pp_mods mods);
+        pp_mods mods); *)
     match Event.resolve (Key (state, key, mods)) res with
     | Event.Accepted actions ->
         callback_resolver := None;
@@ -645,11 +662,11 @@ module Ui = struct
 
   let update_bindings ui
       (f : action list Event.t -> action list Event.t) =
-    ui.bindings <- f ui.bindings
+    Lwd.set ui.bindings (f (Lwd.peek ui.bindings))
 
   let chrcallback_ref : (Uchar.t -> unit Lwt.t) ref =
-    ref (fun c ->
-        F.epr "chrcallback: '%a'@." pp_uchar c;
+    ref (fun _c ->
+        (* F.epr "chrcallback: '%a'@." pp_uchar _c; *)
         Lwt.return_unit)
 
   let chrcallback _t (chr : int) : unit Lwt.t =
@@ -691,11 +708,11 @@ module TextEdit = struct
   open Gg
 
   type t = {
-    mutable text : TextBuffer.t;
-    mutable cursor : TextLayout.cursor;
-    mutable mark : int option;
-    mutable scroll : int;
-    mutable rows : int;
+    text : TextBuffer.t;
+    cursor : TextLayout.cursor Lwd.var;
+    mark : int option Lwd.var;
+    scroll : int Lwd.var;
+    rows : int Lwd.var;
     text_format : TextLayout.format;
     formatter :
       (Ui.t -> TextBuffer.t -> float -> TextLayout.layout) option;
@@ -715,8 +732,8 @@ module TextEdit = struct
 
   let col t =
     TextBuffer.fold_string t.text (fun s ->
-        t.cursor.index
-        - Str.search_backward (Str.regexp "^") s t.cursor.index)
+        let c = Lwd.peek t.cursor in
+        c.index - Str.search_backward (Str.regexp "^") s c.index)
 
   let rec newlines (s : string) (i : int) : int list =
     match String.index_from_opt s i '\n' with
@@ -744,41 +761,38 @@ module TextEdit = struct
   let scroll_update ({ text; cursor; scroll; rows; _ } as t : t) :
       unit Lwt.t =
     TextBuffer.fold_string text (fun s ->
+        let cursor = Lwd.peek cursor in
+        let rows = Lwd.peek rows in
         let slen = String.length s in
-        (if cursor.index < scroll then
-           match
-             String.rindex_from_opt s
-               (min (slen - 1) (cursor.index - 1))
-               '\n'
-           with
-           | Some i' -> t.scroll <- i' + 1
-           | None -> t.scroll <- 0
-         else
-           match index_rows_from s scroll rows with
-           | None -> ()
-           | Some eow -> (
-               F.epr "eow=%d@." eow;
-               if cursor.index >= eow then
-                 match
-                   rindex_rows_from s
-                     (min (slen - 1) cursor.index)
-                     rows
-                 with
-                 | None -> ()
-                 | Some i' -> t.scroll <- i'));
-        F.epr
-          "scroll_update slen=%d cursor=%d scroll=%d c-s=%d rows=%d@."
-          (String.length s) t.cursor.index t.scroll
-          (cursor.index - t.scroll)
-          rows;
-        debuglayout := true)
+        if cursor.index < Lwd.peek scroll then
+          match
+            String.rindex_from_opt s
+              (min (slen - 1) (cursor.index - 1))
+              '\n'
+          with
+          | Some i' -> Lwd.set t.scroll (i' + 1)
+          | None -> Lwd.set t.scroll 0
+        else
+          match index_rows_from s (Lwd.peek scroll) rows with
+          | None -> ()
+          | Some eow -> (
+              if cursor.index >= eow then
+                match
+                  rindex_rows_from s
+                    (min (slen - 1) cursor.index)
+                    rows
+                with
+                | None -> ()
+                | Some i' -> Lwd.set t.scroll i'))
 
   let cursor_update (t : t) (f : int -> int) : unit Lwt.t =
     col t >>= fun last_col ->
     TextBuffer.fold_string t.text (fun s ->
-        t.cursor <-
-          TextLayout.cursor ~last_col
-            (f t.cursor.index |> max 0 |> min (String.length s)))
+        Lwd.set t.cursor
+          (TextLayout.cursor ~last_col
+             (f (Lwd.peek t.cursor).index
+             |> max 0
+             |> min (String.length s))))
     >>= fun () -> scroll_update t
 
   let cursor_move (t : t) (amt : int) : unit Lwt.t =
@@ -825,16 +839,18 @@ module TextEdit = struct
                          Str.search_forward (Str.regexp "$")
                        in
                        let next_bol =
-                         min sn (seol s t.cursor.index + 1)
+                         min sn (seol s (Lwd.peek t.cursor).index + 1)
                        in
                        let next_line_len =
                          seol s next_bol - next_bol
                        in
                        next_bol
                        +
-                       if t.cursor.last_col > next_line_len then
-                         next_line_len
-                       else min next_line_len t.cursor.last_col)
+                       if (Lwd.peek t.cursor).last_col > next_line_len
+                       then next_line_len
+                       else
+                         min next_line_len
+                           (Lwd.peek t.cursor).last_col)
                    >>= cursor_set t);
              ]
         |> adds
@@ -851,7 +867,7 @@ module TextEdit = struct
                        let sbol =
                          Str.search_backward (Str.regexp "^") s
                        in
-                       let bol = sbol t.cursor.index in
+                       let bol = sbol (Lwd.peek t.cursor).index in
                        if bol > 0 then
                          let prev_bol = sbol (max 0 (bol - 1)) in
                          let prev_line_len = bol - 1 - prev_bol in
@@ -862,10 +878,14 @@ module TextEdit = struct
                            t.cursor.index bol prev_bol prev_line_len; *)
                          prev_bol
                          +
-                         if t.cursor.last_col > prev_line_len then
-                           prev_line_len
-                         else min prev_line_len t.cursor.last_col
-                       else t.cursor.index)
+                         if
+                           (Lwd.peek t.cursor).last_col
+                           > prev_line_len
+                         then prev_line_len
+                         else
+                           min prev_line_len
+                             (Lwd.peek t.cursor).last_col
+                       else (Lwd.peek t.cursor).index)
                    >>= cursor_set t);
              ]
         |> adds (* EOL *)
@@ -879,14 +899,14 @@ module TextEdit = struct
                    TextBuffer.fold_string t.text (fun s ->
                        let bol =
                          Str.search_backward (Str.regexp "^") s
-                           t.cursor.index
+                           (Lwd.peek t.cursor).index
                        in
                        let eol =
                          Str.search_forward (Str.regexp "$") s
-                           t.cursor.index
+                           (Lwd.peek t.cursor).index
                        in
-                       t.cursor <-
-                         TextLayout.cursor ~last_col:(eol - bol) eol));
+                       Lwd.set t.cursor
+                       @@ TextLayout.cursor ~last_col:(eol - bol) eol));
              ]
         |> adds (* BOL *)
              [
@@ -897,10 +917,10 @@ module TextEdit = struct
                Custom
                  (fun () ->
                    TextBuffer.fold_string t.text (fun s ->
-                       t.cursor <-
-                         TextLayout.cursor ~last_col:0
-                           (Str.search_backward (Str.regexp "^") s
-                              t.cursor.index)));
+                       Lwd.set t.cursor
+                       @@ TextLayout.cursor ~last_col:0
+                            (Str.search_backward (Str.regexp "^") s
+                               (Lwd.peek t.cursor).index)));
              ]
         |> adds
              [
@@ -910,20 +930,19 @@ module TextEdit = struct
              [
                Custom
                  (fun () ->
-                   match t.mark with
+                   match Lwd.peek t.mark with
                    | Some mark ->
-                       TextBuffer.remove t.text (mark, t.cursor.index)
-                       >>= fun text ->
-                       t.text <- text;
-                       t.mark <- None;
-                       cursor_set t (min mark t.cursor.index)
+                       TextBuffer.remove t.text
+                         (mark, (Lwd.peek t.cursor).index)
+                       >>= fun _ ->
+                       Lwd.set t.mark None;
+                       cursor_set t
+                         (min mark (Lwd.peek t.cursor).index)
                    | None ->
-                       if t.cursor.index > 0 then (
+                       if (Lwd.peek t.cursor).index > 0 then
                          TextBuffer.remove_uchar t.text
-                           (t.cursor.index - 1)
-                         >>= fun text ->
-                         t.text <- text;
-                         cursor_move t (-1))
+                           ((Lwd.peek t.cursor).index - 1)
+                         >>= fun _ -> cursor_move t (-1)
                        else Lwt.return_unit);
              ]
         |> adds
@@ -933,20 +952,19 @@ module TextEdit = struct
                  (fun () ->
                    TextBuffer.fold_string t.text (fun s ->
                        TextBuffer.remove t.text
-                         ( t.cursor.index,
+                         ( (Lwd.peek t.cursor).index,
                            let eol =
                              Str.search_forward (Str.regexp "$") s
-                               t.cursor.index
+                               (Lwd.peek t.cursor).index
                            in
                            if
-                             eol == t.cursor.index
+                             eol == (Lwd.peek t.cursor).index
                              && String.length s > eol
                            then eol + 1
                            else eol )
-                       >>= fun text ->
-                       t.text <- text;
-                       t.mark <- None;
-                       cursor_set t t.cursor.index)
+                       >>= fun _ ->
+                       Lwd.set t.mark None;
+                       cursor_set t (Lwd.peek t.cursor).index)
                    >>= fun u -> u);
              ]
         |> adds
@@ -956,30 +974,26 @@ module TextEdit = struct
              [
                Custom
                  (fun () ->
-                   TextBuffer.insert_uchar t.text t.cursor.index
-                     (Uchar.of_char '\n')
-                   >>= fun text ->
-                   t.text <- text;
-                   cursor_move t 1);
+                   TextBuffer.insert_uchar t.text
+                     (Lwd.peek t.cursor).index (Uchar.of_char '\n')
+                   >>= fun _ -> cursor_move t 1);
              ]
         |> adds
              [ [ Key (Press, Space, [ Control ]) ] ] (* Mark set *)
              [
                Custom
                  (fun () ->
-                   t.mark <-
-                     (match t.mark with
+                   Lwd.set t.mark
+                     (match Lwd.peek t.mark with
                      | Some _ -> None
-                     | None -> Some t.cursor.index);
+                     | None -> Some (Lwd.peek t.cursor).index);
                    Lwt.return_unit);
              ]);
     (* WARN XXX TKTK TODO this is probably "breaking" the lwt context and being used in other calls to Lwt_main.run *)
     (Ui.chrcallback_ref :=
        fun c ->
-         TextBuffer.insert_uchar t.text t.cursor.index c
-         >>= fun text ->
-         t.text <- text;
-         cursor_move t 1
+         TextBuffer.insert_uchar t.text (Lwd.peek t.cursor).index c
+         >>= fun _ -> cursor_move t 1
        (* This creates a giant stack of calls lol
           >>= fun () -> !Ui.chrcallback_ref c *));
     Lwt.return_unit
@@ -989,10 +1003,10 @@ module TextEdit = struct
     let t =
       {
         text;
-        cursor = TextLayout.cursor 0;
-        mark = None;
-        scroll = 0;
-        rows = 0;
+        cursor = Lwd.var (TextLayout.cursor 0);
+        mark = Lwd.var None;
+        scroll = Lwd.var 0;
+        rows = Lwd.var 0;
         text_format;
         formatter = None;
         password = false;
@@ -1024,7 +1038,7 @@ module Layout = struct
     [ `Box of [ `H | `V | `Z ] * frame list
     | `String of string
     | `Buffer of TextBuffer.t
-    | `TextEdit of TextEdit.t
+    | `TextEdit of TextEdit.t * TextLayout.layout Lwd.root
     | `None ]
 
   and size = [ `Fixed of size2 | `Max | `Min ]
@@ -1043,8 +1057,14 @@ module Layout = struct
         margin = Margin.symmetric 10. 10.;
       }
 
-  let textedit ?size ?(style = textedit_style) te =
-    frame ?size ~style (`TextEdit te)
+  let textedit ?size ?(style = textedit_style) (t : TextEdit.t) =
+    let open TextLayout in
+    simple t.text ~start:(Lwd.get t.scroll) ~format:t.text_format
+      (Option.value ~default:80. t.desired_width)
+    |> with_cursor (Lwd.get t.cursor)
+    |> with_mark (Lwd.get t.mark) (Lwd.get t.cursor)
+    |> Lwd.observe
+    |> fun root -> frame ?size ~style (`TextEdit (t, root))
 
   let pp_dir ppf (t : [ `H | `V | `Z ]) =
     F.pf ppf "%s"
@@ -1112,26 +1132,23 @@ module Painter = struct
     Text.set_align t ~align:Align.(left lor top)
 
   let text_layout (t : Gv.t) (rect : box2) (te : TextEdit.t)
-      (g : TextLayout.layout) : box2 Lwt.t =
+      (layout : TextLayout.layout Lwd.root) : box2 Lwt.t =
+    let g = Lwd.quick_sample layout in
     let line_height =
       Option.value ~default:(Gv.Text.metrics t).line_height
         g.line_height
     in
     let max_rows = Int.of_float (Box2.h rect /. line_height) in
-    te.rows <- max_rows;
+    Lwd.set te.rows max_rows;
     let lines = Gv.Text.make_empty_rows max_rows in
     TextBuffer.contents g.text >>= fun contents ->
     let contents_len = String.length contents in
     let row_count =
       Gv.Text.break_lines t ~break_width:(Box2.w rect) ~max_rows
-        ~lines ~start:te.scroll contents
+        ~lines ~start:(Lwd.peek te.scroll) contents
     in
     Seq.fold_left
       (fun ((cur, start) : p2 * int) (row : Gv.Text.text_row) ->
-        if !debuglayout then
-          F.epr "start=%d row=%a %a @." start pp_text_row row
-            F.(brackets @@ list TextLayout.pp_section)
-            g.sections;
         let sections =
           List.filter
             (fun (r : TextLayout.section) ->
@@ -1174,18 +1191,17 @@ module Painter = struct
         |> fun cur'' ->
         ( V2.(v (max (x cur) (x cur'')) (y cur'' +. line_height)),
           row.next ))
-      (Box2.o rect, te.scroll)
+      (Box2.o rect, Lwd.peek te.scroll)
       (Seq.take row_count (Array.to_seq lines))
     |> fst
     |> (fun cur''' -> V2.(cur''' - v 0. line_height))
     |> Box2.(of_pts (o rect))
     |> Lwt.return
 
-  let rec layout (box : box2) (ui : Ui.t) (frame : frame) : box2 Lwt.t
-      =
-    let box' = Margin.inner frame.style.margin box in
-    if !debuglayout then F.epr "layout box'=%a@." Gg.Box2.pp box';
-    (match frame.t with
+  let rec layout (box : box2) (ui : Ui.t) ({ t; style; _ } : frame) :
+      box2 Lwt.t =
+    let box' = Margin.inner style.margin box in
+    (match t with
     | `Box (dir, ll) ->
         Lwt_list.fold_left_s
           (fun (c : box2) f ->
@@ -1199,28 +1215,14 @@ module Painter = struct
             in
             Lwt.return c')
           box' ll
-    | `TextEdit t ->
-        TextLayout.(
-          simple t.text ~start:t.scroll ~format:t.text_format
-            (Option.value ~default:(Box2.w box') t.desired_width)
-          >>= fun layout ->
-          with_cursor t.cursor layout
-          |> with_mark t.mark t.cursor.index
-          |> text_layout ui.gv box' t)
+    | `TextEdit (t, root) -> text_layout ui.gv box' t root
     | _ -> Lwt.return box)
     >>= fun r ->
     let r' =
       Box2.add_pt r
-        V2.(
-          Box2.max r
-          + v frame.style.margin.right frame.style.margin.bottom)
-      |> Margin.outer frame.style.margin
+        V2.(Box2.max r + v style.margin.right style.margin.bottom)
+      |> Margin.outer style.margin
     in
-    draw_box ui.gv ~box:r' ~style:frame.style;
+    draw_box ui.gv ~box:r' ~style;
     Lwt.return r'
-
-  let layout a b c =
-    let r = layout a b c in
-    debuglayout := false;
-    r
 end

oplevel.ml

@@ -18,7 +18,7 @@ end
 let errorcb error desc =
   Printf.printf "GLFW error %d: %s\n%!" error desc
 
-let load_data vg =
+let load_fonts vg =
   let _ = Gv.Text.create vg ~name:"mono" ~file:"./assets/mono.ttf" in
   let _ =
     Gv.Text.create vg ~name:"icons" ~file:"./assets/entypo.ttf"
@@ -62,8 +62,6 @@ let () =
   in
 
   let graph = Perfgraph.init Perfgraph.FPS "Frame Time" in
-  let _odata = load_data ctx in
-  let continue = ref true in
   let min_fps = ref Float.max_float in
   let max_fps = ref Float.min_float in
 
@@ -78,9 +76,11 @@ let () =
   in
 
   let ui =
-    Ogui.Ui.window ctx ~window Gg.(Box2.v P2.o (P2.v 500. 500.))
+    Ogui.Ui.window ctx ~window
+      (Lwd.var Gg.(Box2.v P2.o (P2.v 500. 500.)))
   in
 
+  load_fonts ui.gv;
   GLFW.setKeyCallback ~window
     ~f:
       (Some
@@ -100,7 +100,7 @@ let () =
 
   F.pr "oplevel.ml: building initial page@.";
   let page =
-    ref
+    Lwd.var
       Layout.(
         vbox
           ~style:
@@ -108,82 +108,76 @@ let () =
           [
             textedit
               (TextEdit.multiline ui
-                 (TextBuffer.of_repo
-                    ~path:[ ".config"; "init.ml" ]
-                    ~repo:rootrepo));
+                 (Lwt_main.run
+                    (TextBuffer.of_repo
+                       ~path:[ ".config"; "init.ml" ]
+                       ~repo:rootrepo)));
             (*textedit
               (TextEdit.multiline ui
                  (TextBuffer.of_repo ~path:[ "README" ] ~repo:rootrepo)); *)
           ])
   in
 
-  (let open GLFW in
-   let open Event in
-   let open Ui in
-   Ui.update_bindings ui
-     (adds
+  let open GLFW in
+  let open Event in
+  Ui.update_bindings ui
+    Ui.(
+      adds
         [
           [ Key (Press, X, [ Control ]); Key (Press, E, [ Control ]) ];
         ]
-        [ Custom (fun () -> Lwt.return ()) ]));
+        [ Custom (fun () -> Lwt.return ()) ]);
   F.pr "oplevel.ml: entering drawing loop@.";
   let period_min = 1.0 /. 30. in
   let t = GLFW.getTime () |> ref in
-  while (not GLFW.(windowShouldClose ~window)) && !continue do
-    Lwt_main.run
-      ((fun () ->
-         let now = GLFW.getTime () in
-         let dt = now -. !t in
-         t := now;
 
-         Perfgraph.update graph dt;
+  let render page =
+    let now = GLFW.getTime () in
+    let dt = now -. !t in
+    t := now;
 
-         if now > 2. then (
-           let avg = 1. /. Perfgraph.average graph in
-           min_fps := Float.min avg !min_fps;
-           max_fps := Float.max avg !max_fps);
+    Perfgraph.update graph dt;
 
-         let _mx, _my = GLFW.getCursorPos ~window in
-         let win_w, win_h = GLFW.getWindowSize ~window in
+    if now > 2. then (
+      let avg = 1. /. Perfgraph.average graph in
+      min_fps := Float.min avg !min_fps;
+      max_fps := Float.max avg !max_fps);
 
-         Gl.viewport 0 0 win_w win_h;
-         Gl.clear
-           (Gl.color_buffer_bit lor Gl.depth_buffer_bit
-          lor Gl.stencil_buffer_bit);
-         Gl.enable Gl.blend;
-         Gl.blend_func Gl.src_alpha Gl.one_minus_src_alpha;
-         Gl.enable Gl.cull_face_enum;
-         Gl.disable Gl.depth_test;
+    let _mx, _my = GLFW.getCursorPos ~window in
+    let win_w, win_h = GLFW.getWindowSize ~window in
 
-         let width, height = (float win_w, float win_h) in
-         let box =
-           Gg.(Box2.v V2.zero Size2.(v width (height -. 20.)))
-         in
-         Gv.begin_frame ctx ~width ~height ~device_ratio:1.;
-         Perfgraph.render graph ctx (width -. 205.) 5.;
-         (* F.epr "box=%a@." Gg.Box2.pp box;
-            F.epr "Painter.layout=%a@." Gg.Box2.pp *)
-         Painter.layout box ui !page >>= fun _ ->
-         (* Demo.render_demo ctx mx my win_w win_h now !blowup data; *)
-         Gv.end_frame ctx;
+    Gl.viewport 0 0 win_w win_h;
+    Gl.clear
+      (Gl.color_buffer_bit lor Gl.depth_buffer_bit
+     lor Gl.stencil_buffer_bit);
+    Gl.enable Gl.blend;
+    Gl.blend_func Gl.src_alpha Gl.one_minus_src_alpha;
+    Gl.enable Gl.cull_face_enum;
+    Gl.disable Gl.depth_test;
 
-         Gc.major_slice 0 |> ignore;
-         GLFW.swapBuffers ~window;
-         GLFW.pollEvents ();
-         Unix.sleepf
-           Float.(max 0. (period_min -. GLFW.getTime () +. !t));
-         Lwt.return_unit)
-         ())
+    let width, height = (float win_w, float win_h) in
+    let box = Gg.(Box2.v V2.zero Size2.(v width (height -. 20.))) in
+    Gv.begin_frame ctx ~width ~height ~device_ratio:1.;
+    Perfgraph.render graph ctx (width -. 205.) 5.;
+    (* F.epr "box=%a@." Gg.Box2.pp box;
+       F.epr "Painter.layout=%a@." Gg.Box2.pp *)
+    Painter.layout box ui page >>= fun _ ->
+    (* Demo.render_demo ctx mx my win_w win_h now !blowup data; *)
+    Gv.end_frame ctx;
+
+    Gc.major_slice 0 |> ignore;
+    GLFW.swapBuffers ~window;
+    GLFW.pollEvents ();
+    Unix.sleepf Float.(max 0. (period_min -. GLFW.getTime () +. !t));
+    Lwt.return_unit
+  in
+
+  while not GLFW.(windowShouldClose ~window) do
+    Lwt_main.run (render (Lwd.peek page))
   done;
 
   Printf.printf "MIN %.2f\n" !min_fps;
-  Printf.printf "MAX %.2f\n%!" !max_fps;
-
-  if Array.length Sys.argv = 1 then
-    while not GLFW.(windowShouldClose ~window) do
-      GLFW.pollEvents ();
-      Unix.sleepf 0.25
-    done
+  Printf.printf "MAX %.2f\n%!" !max_fps
 
 (* let out_ppf =
      Format.formatter_of_out_functions
@@ -205,5 +199,3 @@ let () =
 (* ignore
    (Toploop.use_input out_ppf
       (String "#use \"topfind\";;\n#list;;")); *)
-(* ignore (Toploop.use_input Format.std_formatter (String text)); *)
-(* Wait for it to be closed. *)