Is there an opening in June for a few speakers?

[Stephen Adams]

Hello everyone, 

Myself and a group of people from the University of Minnesota, Morris have been working for the past year on transitioning our introductory class from Racket to Clojure. We are wondering if there was room in the June meeting to have us talk with you about what we are doing and to hear your thoughts. 

-- Stephen Adams

[Nick Bauman]

I don't control the schedule at all, but wow, this topic is really near and dear to my heart. For starters, Clojure doesn't have TCO, which I would think is something that might be important to consider from many perspectives.

So things like this (from SICP, section 2.3.4):

(define (decode bits tree)
  (define (decode-1 bits current-branch)
    (if (null? bits)
        '()
        (let ((next-branch
               (choose-branch (car bits) current-branch)))
          (if (leaf? next-branch)
              (cons (symbol-leaf next-branch)
                    (decode-1 (cdr bits) tree))
              (decode-1 (cdr bits) next-branch)))))
  (decode-1 bits tree))


Have to be done more like this in Clojure:

(defn decode
  [bits tree]
  (loop [my-bits bits
         current-branch tree
         decoded-seq []]
    (if (not (seq my-bits))
      decoded-seq

      (let [next-branch (choose-branch (first my-bits) current-branch)]
        (if (leaf? next-branch)
          (recur (rest my-bits) tree (conj decoded-seq (symbol-leaf next-branch)))
          (recur (rest my-bits) next-branch decoded-seq))))))


How is that working? Do you guys lament the lack of TCO in Clojure? Personally, I find the lack of TCO in Clojure requires a different mindset than what you bring to a Scheme. And I'm not sure it's all good. Not to mention that my version of decode up there is single threaded, where outwardly the Scheme version appears as though it could run on multiple cores.



Thanks for offering to talk! I'm very excited about it.


-Nick

-- Stephen Adams

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[Brian Maddy]

Stephen, that would certainly be a fun discussion! Would the July meeting possibly work for you? We don't have any other speakers lined up for June and it would be nice to have our nights be presentations xor hack nights (it's hard to get into things with only half a night I think). If that doesn't work for you we can squeeze you into June. Let me know.

Nick, you may find this interesting; apparently, Chris Frisz and Daniel Friedman (the guy behind miniKanren) came up with a way to do CTO in Clojure using continuations and thunks. It doesn't seem like something you'd want to use on production code yet (it only works with a subset of Clojure), but it certainly is interesting. I haven't read the blog post, but the presentation is good.

Code: https://github.com/cjfrisz/clojure-tco

Presentation: http://www.youtube.com/watch?v=RLqqGSthmC0

Blog: http://www.chrisfrisz.com/blog/Research/a-long-overdue-ctco-intro/

Cheers,

Brian

[Stephen Adams]

It would be really nice to be in June. The coordinator of the project will be out of the country for the July meetup.

[Nick Bauman]

Pretty interesting. Thanks for the followup, Brian.

[Brian Maddy]

Sounds good, let's to June then.

Does anyone else have something they'd be willing to present in June?

[Stephen Adams]

So we are planning about 25 minutes of presentation and then we want to have time for questions and discussion. Does this work for you guys?

[Brian Maddy]

Yep, that will work great--I'm looking forward to it!