properly handle input events. add some comments wrt. keyboard layout.

ViewModels/GridViewModel.fs

@@ -15,6 +15,7 @@ open System
 open model
 open widgets
 open System.Collections.Generic
+open Avalonia.Interactivity
 
 #nowarn "0025"
 
@@ -46,7 +47,7 @@ and GridViewModel(_gridid: int, ?_parent: GridViewModel, ?_gridsize: GridSize) a
     let m_popupmenu_vm           = new PopupMenuViewModel()
     let m_child_grids            = ResizeArray<GridViewModel>()
     let m_resize_ev              = Event<IGridUI>()
-    let m_input_ev               = Event<int * InputEvent>()
+    let m_input_ev               = Event<int * InputEvent * RoutedEventArgs>()
     let m_ext_winclose_ev        = Event<unit>()
     let m_drawops                = ResizeArray() // keeps the scroll and putBuffer operations
 
@@ -93,7 +94,7 @@ and GridViewModel(_gridid: int, ?_parent: GridViewModel, ?_gridsize: GridSize) a
     static let mutable g_create_seq = 0
     let m_create_seq = g_create_seq
 
-    let raiseInputEvent id e = m_input_ev.Trigger(id, e)
+    let raiseInputEvent id e ev = m_input_ev.Trigger(id, e, ev)
 
     let getPos (p: Point) =
         int(p.X / m_glyphsize.Width), int(p.Y / m_glyphsize.Height)
@@ -842,7 +843,7 @@ and GridViewModel(_gridid: int, ?_parent: GridViewModel, ?_gridsize: GridSize) a
     (*******************   Events   ***********************)
 
     member __.OnKey (e: KeyEventArgs) = 
-        raiseInputEvent _gridid <| InputEvent.Key(e.KeyModifiers, e.Key)
+        raiseInputEvent _gridid (InputEvent.Key(e.KeyModifiers, e.Key)) e
 
     member __.OnMouseDown (e: PointerPressedEventArgs) (root: Avalonia.VisualTree.IVisual) = 
         if m_mouse_en then
@@ -856,7 +857,7 @@ and GridViewModel(_gridid: int, ?_parent: GridViewModel, ?_gridsize: GridSize) a
               m_mouse_pressed_widget <- wid
               model.GuiWidgetMouseDown vm.BufNr wid
             else
-              raiseInputEvent vm.GridId <| InputEvent.MousePress(e.KeyModifiers, r, c, button)
+              raiseInputEvent vm.GridId (InputEvent.MousePress(e.KeyModifiers, r, c, button)) e
 
     member __.OnMouseUp (e: PointerReleasedEventArgs) (root: Avalonia.VisualTree.IVisual) = 
         if m_mouse_en then
@@ -869,7 +870,7 @@ and GridViewModel(_gridid: int, ?_parent: GridViewModel, ?_gridsize: GridSize) a
               model.GuiWidgetMouseUp m_mouse_pressed_vm.BufNr m_mouse_pressed_widget
               m_mouse_pressed_widget <- -1
             else
-              raiseInputEvent m_mouse_pressed_vm.GridId <| InputEvent.MouseRelease(e.KeyModifiers, r, c, button)
+              raiseInputEvent m_mouse_pressed_vm.GridId (InputEvent.MouseRelease(e.KeyModifiers, r, c, button)) e
 
     member __.OnMouseMove (e: PointerEventArgs) (root: Avalonia.VisualTree.IVisual) = 
         if m_mouse_en && m_mouse_pressed <> MouseButton.None then
@@ -884,14 +885,14 @@ and GridViewModel(_gridid: int, ?_parent: GridViewModel, ?_gridsize: GridSize) a
                   #if DEBUG
                   trace m_mouse_pressed_vm.GridId "mousemove: %d %d" r c
                   #endif
-                  raiseInputEvent m_mouse_pressed_vm.GridId <| InputEvent.MouseDrag(e.KeyModifiers, r, c, m_mouse_pressed)
+                  raiseInputEvent m_mouse_pressed_vm.GridId (InputEvent.MouseDrag(e.KeyModifiers, r, c, m_mouse_pressed)) e
 
     member __.OnMouseWheel (e: PointerWheelEventArgs) (root: Avalonia.VisualTree.IVisual) = 
         if m_mouse_en then
             let x, y = e.GetPosition root |> getPos
             let _, _, vm, r, c, _ = this.FindTargetVm y x
             let dx, dy = e.Delta.X, e.Delta.Y
-            raiseInputEvent vm.GridId <| InputEvent.MouseWheel(e.KeyModifiers, r, c, dx, dy)
+            raiseInputEvent vm.GridId (InputEvent.MouseWheel(e.KeyModifiers, r, c, dx, dy)) e
 
     member __.OnTextInput (e: TextInputEventArgs) = 
-        raiseInputEvent _gridid <| InputEvent.TextInput(e.Text)
+        raiseInputEvent _gridid (InputEvent.TextInput(e.Text)) e

Views/Grid.xaml.fs

@@ -260,7 +260,6 @@ type Grid() as this =
   let subscribeAndHandleInput fn (ob: IObservable<#Avalonia.Interactivity.RoutedEventArgs>) =
     ob.Subscribe(fun e ->
       if not e.Handled then
-        //e.Handled <- true
         doWithDataContext(fn e))
 
   let drawDebug(dc: IDrawingContextImpl) =

input.fs

@@ -6,6 +6,7 @@ open neovim
 open Avalonia.Input
 open System
 open FSharp.Control.Reactive
+open Avalonia.Interactivity
 
 let inline trace fmt = trace "input" fmt
 
@@ -270,6 +271,19 @@ let (|Special|Normal|Rejected|) (x: InputEvent) =
     match x with
     | Key(_, k) when RejectKeys.Contains k                        -> Rejected  
     | Key(DoesntBlockTextInput, k) when TextInputKeys.Contains k  -> Rejected  
+    // !!Note from here on, all TextInput-triggering keys should have been filtered.
+    // All that survived the purge are either non-textinput-triggering keys, or
+    // textinput-triggering keys with non-shift modifier active.
+    // The (possibly unwanted) side effect of this approach is the inconsistency
+    // between TextInput and modifier-active Key:
+    //
+    // | en-US kbd sequence | en result (sent to nvim) | de result (sent to nvim) |
+    // | ------------------ | ------------------------ | ------------------------ |
+    // | z                  | z                        | y                        |
+    // | Ctrl-z             | <C-z>                    | <C-z>                    |
+    // | '                  | '                        | ä                        |
+    // | Ctrl-'             | <C-'>                    | <C-'>                    |
+    //
     | Key(m, Key.Back)                                            -> 
       if m = KeyModifiers.Control then
         blockNextTextInput <- true
@@ -379,21 +393,23 @@ let rec ModifiersPrefix (x: InputEvent) =
     | TextInput _ -> ""
     | _ -> ""
 
-let onInput (nvim: Nvim) (input: IObservable<int*InputEvent>) =
-  let key,mouse = input |> Observable.partition(function | _, InputEvent.Key _ | _, InputEvent.TextInput _ -> true | _ -> false)
+let onInput (nvim: Nvim) (input: IObservable<int*InputEvent*RoutedEventArgs>) =
+  let key,mouse = input |> Observable.partition(function | _, InputEvent.Key _, _ | _, InputEvent.TextInput _, _ -> true | _ -> false)
   // translate to nvim input sequence
   let key = 
     key
-    |> Observable.choose(fun (_, x) ->
+    |> Observable.choose(fun (_, x, ev) ->
         match x with
-        | TextInput "<"        -> Some "<LT>"
-        | TextInput txt        -> 
-          if blockNextTextInput then
+        | TextInput txt -> 
+          ev.Handled <- true
+          if txt = "<" then Some "<LT>"
+          else if blockNextTextInput then
             blockNextTextInput <- false
             None
-          else 
+          else
             Some txt
         | InputEvent.Key _     -> 
+          ev.Handled <- true
           let pref = ModifiersPrefix x
           match x,pref with
           | (Special sp), ""   -> Some(sprintf "<%s>" sp)
@@ -404,13 +420,15 @@ let onInput (nvim: Nvim) (input: IObservable<int*InputEvent>) =
             #if DEBUG
             trace "rejected: %A" x
             #endif
+            ev.Handled <- false
             None
         | _ -> None
         )
 
   let mouse =
     mouse
-    |> Observable.choose(fun (gridid, x) -> 
+    |> Observable.choose(fun (gridid, x, ev) -> 
+      ev.Handled <- true
       let pref = ModifiersPrefix x
       match x with
       |  MousePress(_, r, c, NvimSupportedMouseButton but)   -> Some(gridid, MB but, "press", r, c, 1, pref)

ui.fs

@@ -15,6 +15,7 @@ open System
 open Avalonia.Media.TextFormatting
 open System.Globalization
 open SkiaSharp
+open Avalonia.Interactivity
 
 #nowarn "0009"
 
@@ -100,7 +101,7 @@ type IGridUI =
     /// Number of columns
     abstract GridWidth: int
     abstract Resized: IEvent<IGridUI>
-    abstract Input: IEvent<int*InputEvent>
+    abstract Input: IEvent<int*InputEvent*RoutedEventArgs>
     abstract BackgroundColor: Color
     abstract HasChildren: bool
     abstract RenderScale: float