(.module:
  [library
   [lux "*"
    [abstract
     [equivalence {"+" [Equivalence]}]]
    [data
     ["." sum]
     ["." text]]
    [world
     [file {"+" [Path]}]
     [net {"+" [URL]}]]]])

(type: .public Origin
  (Variant
   (#Local Path)
   (#Remote URL)))

(def: .public equivalence
  (Equivalence Origin)
  ($_ sum.equivalence
      text.equivalence
      text.equivalence
      ))