cup_spec   = package? import* class? code* symbol+ precedence* start? production+
package    = "package" ID ("." ID)* ";"  
import     = "import" ID ("." ID)* (".*")? ";"
class      = "class" ID ";"
code       = ("action""code"|"parser""code"|"init""with"|"scan""with") CODE ";"?
symbol     = ("terminal"|"non""terminal"|"nonterminal") JTYPE? ID ("," ID)* ";"
precedence = "precedence" ("left"|"right"|"nonassoc") ID ("," ID)* ";" 
start      = "start" "with" ID ";"    
production = ID "::=" rhs ("|" rhs)* ";"
       rhs = ( ID (":" ID)? | CODE )* ("%prec" ID)? 
ID         = [:jletter:] [:jletterdigit:]*
JTYPE      = /* Any non primitive Java Type */
CODE       = "{:" /* Any Java code */ ":}"