* error message *)
exception Error of int * int * string
-val notation_lexer: (string * string) Token.glexer
+val level1_pattern_lexer: (string * string) Token.glexer
+val level2_ast_lexer: (string * string) Token.glexer
+val level2_meta_lexer: (string * string) Token.glexer
+
+val add_level2_ast_keyword: string -> unit (** non idempotent *)
+val remove_level2_ast_keyword: string -> unit (** non idempotent *)