A clj snippet #5

Today's post concerns nothing fancy, but rather touches upon some basic feature of Clojure which I didn't know about until recently. Common Lisp has this nice way of specifying keyword parameters.

(defun foo (x &key y z)

   (list x y z))

(foo 1 :y 2)

(foo 1 :z 2 :y 3)

I thought Clojure doesn't support keyword parameters, but it actually does. There is a map destructuring syntax for rest arguments.

(defn foo [x & {:keys [y z]}]

  (list x y z))

(foo 1 :y 2)

(foo 1 :z 2 :y 3)

This works because map destructuring also works with sequences.

Stay safe.