boxen.clj

;; Let's not repeat ourselves
(def unix-good "This is a Unix box and therefore good")
(def windows-bad "This is a Windows box and therefore bad")
(def mac-superior "This is a Macintosh box and therefore far superior")
(def not-box "This is not a box")

;; Returning a string given some other string is not a unique and special
;; snowflake. Someone else did this before you did, so the language has it built
;; in. It's in an agent so it's easy to add to.
(def boxen (agent {"Linux" unix-good
                   "SunOS" unix-good
                   "Mac OS" mac-superior
                   "Windows NT" windows-bad
                   "Windows 95" windows-bad}))

(defn get-box []
  (get @boxen (System/getProperty "os.name") not-box))

;; Oh, let's add something. Someone using this as a library could do this too.

(def osx-arrogant "This is both a Macintosh and a Unix box. I look down my nose at you.")

(send boxen assoc "Mac OS X" osx-arrogant)

;; Did I mention this is all non-blocking and thread-safe?