anchor.diff:              | NormalMode, [ "u" ] -> [ run Undo Nothing ]
               | NormalMode, [ "d"; "d" ] -> [ run Delete WholeLine ]
               | NormalMode, [ "c"; "c" ] -> [ run Delete WholeLine; run (SwitchMode InsertMode) Nothing ]
  +            | NormalMode, [ "y"; "y" ] -> [ run Yank WholeLine ]
               | NormalMode, [ "C" ] -> [ run Delete EndOfLine; run (SwitchMode InsertMode) Nothing ]
               | NormalMode, [ "D" ] -> [ run Delete EndOfLine ]
               | NormalMode, [ "x" ] -> [ run Delete CurrentLocation ]
  
positive.code:         | "d" -> Some Delete
          | "c" -> Some Change
          | "v" -> Some Visual
          | "g" -> Some Go
          | _ -> None
  
  
negative.code: type CommandType =
      | Move
      | Visual
      | Yank
      | Delete
      | Change
      | Go
  