Sketch = <shape> Composite(Box) Mode. 
// Sketch = <shape> Shape Mode. 
Shape : 
  VisualComponent |
//  ShapeGroup |
  Box | 
  Line
  *common* <coords> Coordinates.

// Repetition-Buffer rule
ShapeGroup = "{" <shapes> List(Shape) "}".
VisualComponents = <components> List(VisualComponent).

VisualComponent : ShapeGroup | ADecorator.
ADecorator : ScrollDecorator | BorderDecorator *common*
  VisualComponents.
ScrollDecorator = "scroll".
BorderDecorator = "border".

Coordinates = 
  <p1> Point
  <p2> Point.
Point = 
  <x> Integer
  <y> Integer.
Box = "box".
Line = "line".
Mode : Gesture | Transfer | Drag *common*
  [<next> Mode].
Gesture = "gesture" Shape <origin> Point.
Drag = "drag" <shapes> ShapeGroup <last> Point.
Transfer = "transfer" <shapes> ShapeGroup <origin> Point.
List(S) ~  {S}.

Main = .
Cursor = .
DrawingVisitor = <color> Color.
Color : Black | Red.
Black = "black".
Red = "red".

Decorator(S) : Temp(S) | Decor(S).
Decor(S)        : Decor1(S) | Decor2(S)
		*common* <component> Decorator(S).
Decor1(S) = .
Decor2(S) = .

Composite(S) : Temp(S) | Compound(S).
Compound(S)  = "(" <composites> List(Composite(S)) ")".

Temp(S) = <t> S.