(* Example calls for interp *)

interp(Num(0),
       [],
       NumV(0),
       NumV(0));; (* should be NumV(0) *)

interp(New("simple", []),
       [Class("simple", "object", [], [])],
       NumV(0),
       NumV(0));; (* should be ObjV(Class("simple", "object", [], []), []) *)

interp(Get(New("simple", [Num(12)]), "z"),
       [Class("simple", "object", [Field("z")], [])],
       NumV(0),
       NumV(0));; (* should be NumV(12) *)

interp(DSend(New("simple", [Num(12)]), "add", Num(17)),
       [Class("simple", "object", [Field("z")],
              [Method("add", Add(Get(This, "z"), Arg))])],
       NumV(0),
       NumV(0));; (* should be NumV(29) *)