Add clear method to LTerm_widget.box

examples/double_editor.ml

@@ -27,24 +27,63 @@ let main () =
   let waiter, wakener = Lwt.wait () in
 
   let ctrl_c = [make_key ~ctrl:true @@ `Char 'c'] in
+  let ctrl_d = [make_key ~ctrl:true @@ `Char 'd'] in
   let tab = [make_key @@ `Other LTerm_key.Tab] in
   let quit = [LTerm_edit.Custom (Lwt.wakeup wakener)] in
 
   let vbox = new LTerm_widget.vbox in
 
   let top_editor = new LTerm_edit.edit () in
   let top_frame = frame top_editor in
+  top_frame#set_label "Editor 1";
 
   (* make bottom editor a fixed 10 rows in size *)
   let bottom_editor = new LTerm_edit.edit ~size:{ rows = 10; cols = 1 } () in
   (* changed my mind: make it 5 rows smaller *)
   bottom_editor#set_allocation
     { bottom_editor#allocation with row1 = bottom_editor#allocation.row1 - 5 };
   let bottom_frame = frame bottom_editor in
+  bottom_frame#set_label "Editor 2";
+  let editor_box = new LTerm_widget.vbox in
 
-  vbox#add top_frame;
+  editor_box#add top_frame;
   (* in versions before PR#42 this would either crash or make the bottom editor unusable *)
-  vbox#add ~expand:false bottom_frame;
+  editor_box#add ~expand:false bottom_frame;
+
+  vbox#add editor_box;
+
+  let swap =
+    let top = ref true in
+    let swapper () =
+      if !top then begin
+        editor_box#clear;
+        editor_box#add ~expand:false bottom_frame;
+        editor_box#add top_frame;
+        top := false
+      end else begin
+        editor_box#clear;
+        editor_box#add top_frame;
+        editor_box#add ~expand:false bottom_frame;
+        top := true
+      end in
+    (* Alternative Version (slightly better actually) *)
+    (*
+    let swapper () =
+      if !top then begin
+        editor_box#remove bottom_frame;
+        editor_box#add ~position:0 ~expand:false bottom_frame;
+        top := false
+      end else begin
+        editor_box#remove top_frame;
+        editor_box#add ~position:0 top_frame;
+        top := true
+      end in
+    *)
+    [LTerm_edit.Custom swapper] in
+
+  (* swap on C-d *)
+  top_editor#bind ctrl_d swap;
+  bottom_editor#bind ctrl_d swap;
 
   (* exit on C-c *)
   top_editor#bind ctrl_c quit;
@@ -54,10 +93,15 @@ let main () =
     LTerm_edit.Custom (fun () -> vbox#send_event @@ LTerm_event.Key (make_key key)) in
 
   (* switch editors on Tab *)
+  top_editor#set_focus { top_editor#focus with down = Some (bottom_editor :> LTerm_widget.t) };
+  bottom_editor#set_focus { bottom_editor#focus with up = Some (top_editor :> LTerm_widget.t) };
   top_editor#bind tab [send_key @@ `Other LTerm_key.Down];
   bottom_editor#bind tab [send_key @@ `Other LTerm_key.Up];
 
-  let label = new LTerm_widget.label "Press Tab to switch between editors.\nPress C-c to exit." in
+  let label =
+    let descr =
+      "Press Tab to switch between editors.\nPress C-d to swap editors.\nPress C-c to exit." in
+    new LTerm_widget.label descr in
   vbox#add ~expand:false label;
 
   Lazy.force LTerm.stdout

src/lTerm_widget.mli

@@ -128,6 +128,9 @@ class type box = object
 
   method remove : #t -> unit
     (** [remove widget] remove a widget from the box. *)
+
+  method clear : unit
+    (** [clear] removes all widgets from the box. *)
 end
 
 (** A widget displaying a list of widgets, listed horizontally. *)

src/widget_impl/lTerm_containers_impl.ml

@@ -26,6 +26,7 @@ class type box = object
   inherit t
   method add : ?position : int -> ?expand : bool -> #t -> unit
   method remove : #t -> unit
+  method clear : unit
 end
 
 class virtual abox rc = object(self)
@@ -68,6 +69,13 @@ class virtual abox rc = object(self)
     self#compute_size_request;
     self#compute_allocations;
     self#queue_draw
+
+  method clear =
+    List.iter (fun child -> child.widget#set_parent None) children;
+    children <- [];
+    self#compute_size_request;
+    self#compute_allocations;
+    self#queue_draw
 end
 
 class hbox = object(self)