Primitive Logging System in Clojure.

Logger.clj

(defn print-logger
  [writer]
  #(binding [*out* writer]
     (println %)))
(defn file-logger
  [file]
  #(with-open [f (clojure.java.io/writer file :append true)]
     ((print-logger f) %)))

;; Usage
(def log (file-logger "/tmp/log"))
(log "hi")