Comments on: Keyword Arguments in Clojure, the Right Way

By: Destillat 22-01-2010 | duetsch.info - Open Source, Wet-, Web-, Software

Destillat 22-01-2010 | duetsch.info - Open Source, Wet-, Web-, Software — Fri, 22 Jan 2010 10:09:47 +0000

[...] Keyword Arguments in Clojure, the Right Way [...]

Meikel — Mon, 18 Jan 2010 12:39:37 +0000

Now we have to construct a map on the caller site. But it will probably be an array-map which is faster to construct.

And we can’t use apply anymore:

(let [arguments [x y :key1 val1 :key2 val2]] (apply my-fn a b arguments))

Raises the question whether one needs apply with keyword arguments.

Getting away from the example:
Nice coverage of map destructuring. :)

Abhijith — Sun, 17 Jan 2010 12:16:14 +0000

sweet. Didn’t know that (let [ { :keys [a b] } {:a 1 :b 2} ] [a b] ) was a special case of (let [{a :a b :b} {:a 1 b: 2}] [a b] ). Thanks!

Stuart — Fri, 15 Jan 2010 20:46:38 +0000

Yes, it mixes well. Although I would have written your example as a multiple-arity function, like this:

(defn text-input
([name value] (text-input name value {}))
([name value {:keys [size class]}] …))

Radu Floricica — Fri, 15 Jan 2010 20:37:06 +0000

Should probably be pointed that this mixes really well with normal parameters:

(defn text-input [name value & [{:keys [size class]}] ]
[:input {:name name :value value :size size :class class}])

and can be called either:

(text-input “first_name” “John”)

(text-input “first_name” “John” {:size 20})