SuperClasses = <superclass_comma_list> SuperClass_Comma_list .
Common = .
Term_Bar_list = <first> Nonempty_Term_Bar_list .
Nonempty_Syntax_vertex_List = <it> Syntax_vertex [ <next> Nonempty_Syntax_vertex_List ] .
Regular_syntax = <string> String extends Syntax_vertex.
Neighbors_wc : Construct_ns | Alternat_ns 
			common <construct_ns> Any_vertex_List extends Neighbors.
Cd_graph = <adjacencies> Adjacency_Nlist .
Nonempty_Any_vertex_List = <it> Any_vertex [ <next> Nonempty_Any_vertex_List ] .
Syntax_vertex : Regular_syntax 
			common extends Any_vertex.
Nonempty_SuperClass_Comma_list = <it> SuperClass [ <next> Nonempty_SuperClass_Comma_list ] .
Regular = extends Opt_labeled_term.
Nonempty_Term_Bar_list = <it> Term [ <next> Nonempty_Term_Bar_list ] .
SuperClass = <super_name> Ident .
Optional_term = <opt> Opt_labeled_term_Sandwich extends Any_vertex.
Opt_labeled_term_Sandwich = <first> Syntax_vertex_List <inner> Opt_labeled_term <second> Syntax_vertex_List .
Opt_labeled_term : Labeled | Regular 
			common <vertex> Term extends Any_vertex.
Adjacency_Nlist = <first> Nonempty_Adjacency_Nlist .
Any_vertex : Opt_labeled_term | Optional_term | Syntax_vertex .
Alternat_ns = <alternat_ns> Term_Bar_list [ <common> Common ] extends Neighbors_wc.
Construct_ns = extends Neighbors_wc.
Vertex = <vertex_name> Ident .
Neighbors : Neighbors_wc .
Nonempty_Adjacency_Nlist = <it> Adjacency [ <next> Nonempty_Adjacency_Nlist ] .
Adjacency = <source> Vertex <ns> Neighbors [ <supers> SuperClasses ] .
Term : Normal 
			common <vertex> Vertex .
Normal = extends Term.
Syntax_vertex_List = [ <first> Nonempty_Syntax_vertex_List ] .
Any_vertex_List = [ <first> Nonempty_Any_vertex_List ] .
SuperClass_Comma_list = <first> Nonempty_SuperClass_Comma_list .
Labeled = <label_name> Ident extends Opt_labeled_term.