Getting Clojure

In the Wild

The Clojure language plugin for the LightTable text editor shows off a great example of using an atom to track some fairly complex data.^{[31] [32]} In this case it’s configuration data:

;; Lots of code omitted.

(def my-settings (atom {:name "clj"
                        :dir (fs/absolute-path fs/*cwd*)
                        :type "lein-light-nrepl"
                        :commands [:editor.eval.clj
                                   :editor.clj.doc
                                   :editor.cljs.doc
                                   :editor.clj.hints

                                   ;; Many keywords omitted...

                                   :editor.eval.cljs
                                   :cljs.compile]}))
;; Lots of code omitted.

(defn settings! [setts]
  (swap! my-settings merge setts))

Here we start with an atom containing a map of program settings along with a function that lets us merge new settings into the map. Anytime we need one of the settings, ...