add functionality to delete to chr (equivalent of Vi commands starting with 'df' like 'dfe' to delete to the next 'e', and also add equivalent of 'dFe' to delete backwards)

fcore/app-update.sml

@@ -591,14 +591,25 @@ struct
           | RESIZE_EVENT (width, height) => 
               resizeText (app, width, height))
       | #"d" => 
-          (* todo: delete whole line *)
+          (* delete whole line *)
           clearMode app
       | #"f" => 
-          (* todo: delete to chr, forwards *)
-          clearMode app
+          (case newCmd of
+            CHAR_EVENT chr =>
+              deleteToChr (app, count, Cursor.toNextChr, op+, chr)
+          | KEY_ESC =>
+              clearMode app
+          | RESIZE_EVENT (width, height) => 
+              resizeText (app, width, height))
       | #"F" => 
-          (* todo: delete to chr, backwards *)
-          clearMode app
+          (* delete to chr, backwards *)
+          (case newCmd of
+            CHAR_EVENT chr =>
+              deleteToChr (app, count, Cursor.toPrevChr, op-, chr)
+          | KEY_ESC =>
+              clearMode app
+          | RESIZE_EVENT (width, height) => 
+              resizeText (app, width, height))
       | #"g" => 
           (* todo: same events as handleGo *)
           clearMode app