// DH-nice
// class dictionary
Cd_graph = <first> Adj <rest> Adj_list.
Adj = <vertex> Vertex <ns> Neighbors ".".
Neighbors: Construct | Alternat.
Construct = "=" <c_ns> Any_vertex_list.
Alternat = ":" <first> Vertex "|" <second> Vertex.
Any_vertex : Labeled_vertex | Syntax_vertex.
Syntax_vertex = <string> String.
Labeled_vertex = "<" <label_name> Ident ">" 
                     <class_name> Vertex.
Adj_list: Empty_cd_graph | Cd_graph.
Any_vertex_list: Empty | Nany_vertex_list.
Nany_vertex_list = 
  <first> Any_vertex <rest> Any_vertex_list.
Empty = .
Empty_cd_graph = .
Vertex = <name> Ident.

Main = .