Getting Clojure

In the Wild

Our old friend the built-in = function is a great example of the function-related goodies we’ve been looking at in this chapter:

;; Code edited a bit for clarity.

(defn =
  "Equality. Returns true if x equals y, false if not. Same as
  Java x.equals(y) except it also works for nil, and compares
  numbers and collections in a type-independent manner.
  Clojure's immutable data structures define equals()
  (and thus =) as a value, not an identity, comparison."
  ([x] true)
  ([x y] (clojure.lang.Util/equiv x y))
  ([x y & more]
   (if (clojure.lang.Util/equiv x y)
     (if (next more)
       (recur y (first more) (next more))
       (clojure.lang.Util/equiv y (first more)))
     false)))

The = function takes any number of arguments ...