type:Address:struct
 street:string
 city:string
endtype
type:Person:struct
 name:string
 addr:Address
endtype
value:a10:Address {
 vcity:Ottawa
 vstreet:queen st
}
value:x:Person {
value:addr:Address {
  vcity:Ottawa
  vstreet:queen st
}
 vname:abc
}
