Config using optional named parameters

optional-config.clj

(def ^:dynamic *config* nil)

(defn save [data & {:keys [config] :or {config *config*}}]
  (println (format "Saved %s with %s" data config)))

;; => (save {:a 5 :b 6} :config {:some :config})
;; Saved {:a 5, :b 6} with {:some :config}
;; nil
;; => (binding [*config* {:some :config}] (save {:a 5 :b 6}))
;; Saved {:a 5, :b 6} with {:some :config}
;; nil