Destructure parameter of a Clojure function while keeping the original value.

Question

Can you destructure a function parameter but still have the original available for use? The way I'm doing it now is just using a let form inside the function body, but I wondering if there was a terser way of doing it.

Answer 1

Seems like :as works for functions too:

with vector

(defn test [[x y :as v]]
  {:x x :y y :v v})

(test [1 2 3 4])
=>  {:x 1 :y 2 :v [1 2 3 4]}

with hash-map

(defn test2 [{x :x y :y :as m}]
    {:x x :y y :m m})

(test2 {:x 1 :y 2 :z 3})
=> {:x 1 :y 2 :m {:x 1 :y 2 :z 3}}

See this terrific blog post: http://blog.jayfields.com/2010/07/clojure-destructuring.html