Define clojure hash map without duplicating tokens

Question

I'd like to return a hash-map like so:

(fn [foo bar] {:foo foo :bar bar})

Is it possible to do that without repeating the names? Something like how let allows this:

(let [{:keys [foo bar]} args]
   (...))

See also http://stackoverflow.com/q/20913319/1756702 – A. Webb Jan 26 '14 at 01:42 — A. Webb, Jan 26 '14 at 01:42

Shepmaster · Accepted Answer · 2014-01-26T03:48:52.950

3

The macro:

(defmacro some-hash-thing [& vals]
  (zipmap (map keyword vals) vals))

And in use:

(let [a 4, b 5]
  (some-hash-thing b a))
;; => {:a 4, :b 5}

edited Jan 26 '14 at 03:48

answered Jan 25 '14 at 22:47

Shepmaster

I'd suggest stealing the names from @noisesmith answer: `as-keymap` and `names` are way better. – Shepmaster Jan 25 '14 at 22:58
2

The syntax-quote unquote is extraneous - they cancel each other out. – A. Webb Jan 26 '14 at 02:04
Thanks for pointing that out, @A.Webb. Obviously, I didn't clean it up as much as I could from all my REPL experimenting. I've edited to reflect that. – Shepmaster Jan 26 '14 at 03:48

score 3 · Answer 2 · answered Jan 25 '14 at 22:48

3

(defmacro as-keymap [& names] `(conj {} ~@(map (juxt keyword symbol) names)))

answered Jan 25 '14 at 22:48

noisesmith

2 Answers2