import java.io.*;

ObjectGraph = ":" <objType> Vertex <description> Obj_description.
Obj_description : DTerminal | DConstruction | DRepetition.
DTerminal = <value> String.
DConstruction = "(" <parts> List(Labeled_part) ")".
DRepetition = "{" [ <parts> Comma_list(ObjectGraph) ] "}".
Labeled_part = <label> Label <obj> ObjectGraph.
Label = "<" <lName> Ident ">".
Vertex = <vName> Ident.

List(S) ~ {S}.                                                             
Comma_list(S) ~ S {"," S}.                                                 

Main = .