-- ASDL specicication in ASDL without use of labels
-- * = repetition ? = optional ala. grep
-- Think grep meets Cish prototypes

module Asdl {

  asdl_type = SumType(identifier, field*,constructor, constructor*)
            | ProductType(identifier,field?,field*)

  constructor = Con(identifier, field*)

  field = Id | Option | Sequence 
  attributes (identifier,identifier?)

  op = Plus | Minus | Times | Div
  t = (op bar,op* baz,op?)
  foo = (bar)
  bar = (foo)
}