(.using
 [library
  [lux {"-" Module}]]
 [/
  [descriptor {"+" Descriptor}]
  [document {"+" Document}]])

(type: .public ID
  Nat)

(def: .public runtime
  ID
  0)

(type: .public (Module a)
  (Record
   [#id ID
    #descriptor Descriptor
    #document (Document a)]))