add function to yank inside WORD

fcore/cursor.sml

@@ -624,6 +624,7 @@ struct
   (* equivalent of vi's `E` command *)
   val endOfWORD = ViCapsWordDfa.endOfCurrentWORD
   val endOfWORDForDelete = ViCapsWordDfa.endOfCurrentWORDForDelete
+  val endOfWORDStrict = ViCapsWordDfa.endOfCurrentWORDStrict
 
   (* Prerequisite: 
    * LineGap has been moved to start of line (provided with vi0). *)

fcore/normal-mode/normal-mode.sml

@@ -296,8 +296,8 @@ struct
     fun parseYankInside (app, chr) =
       case chr of
         #"w" => NormalYank.yankInsideWord app
+      | #"W" => NormalYank.yankInsideWORD app
       (*
-      | #"W" => NormalDelete.deleteInsideWORD app
       | #"(" => NormalDelete.deleteInsideChrOpen (app, chr)
       | #"[" => NormalDelete.deleteInsideChrOpen (app, chr)
       | #"{" => NormalDelete.deleteInsideChrOpen (app, chr)

fcore/normal-mode/normal-yank.sml

@@ -269,6 +269,25 @@ struct
       val buffer = LineGap.goToIdx (high, buffer)
       val length = high - low
 
+      val str = LineGap.substring (low, length, buffer)
+      val msg = YANK str
+      val mode = NORMAL_MODE ""
+    in
+      if str = "\n" then app
+      else NormalModeWith.modeAndBuffer (app, buffer, mode, [DRAW msg])
+    end
+
+  fun yankInsideWORD (app: app_type) =
+    let
+      val {buffer, cursorIdx, searchString, ...} = app
+      val buffer = LineGap.goToIdx (cursorIdx, buffer)
+      val low = Cursor.prevWORDStrict (buffer, cursorIdx, 1)
+      val high = Cursor.endOfWORDStrict (buffer, cursorIdx, 1)
+
+      val high = high + 1
+      val buffer = LineGap.goToIdx (high, buffer)
+      val length = high - low
+
       val str = LineGap.substring (low, length, buffer)
       val msg = YANK str
       val mode = NORMAL_MODE ""