Clojure on the Tube

Thought I should share this, as it surprised me. I solved one of the 4Clojure problems on the London Underground today while commuting home, using my smart phone.

I didn’t think it would be possible to write anything useful on such a small device, but with a bit of persistance I was not only able to write some Clojure, I was also able to run it inside a REPL to see what I was doing wrong and iterate on my solution.

If you’ve got an Android phone the REPL I used was Clojure REPL and the local instance of the 4Clojure problems were held on the 4Clojure app. Both apps are pretty nifty. The only thing that slowed me down was trying to type all those parens on the native keyboard.

4Clojure is good resource of problems to help learn Clojure; I’ve been getting rusty recently as my main focus has been JavaScript. And planning my wedding.

For the record, this is the function I wrote:

(fn flatn [lst]
  (if (coll? lst)
    (apply concat (map flatn lst))
    [lst]))

Note that this was done at the north end of the Victoria line, near Finsbury Park. I don’t think I’d have managed it on the Northern line in the City…