1. (deftype X []
  2.   Object
  3.   (toString [this]
  4.     (str "(instance? X this) -> " (instance? X this))))
  5.  
  6. (clojure-version)
  7. ; -> "1.2.0"
  8.  
  9. (str (X.))
  10. ; -> "(instance? X this) -> false"