#clojure – 2012-10-28

2012-10-28

00:03	muhoo	use ALL the cores!
00:03	tomoj	I wonder what's a good way to deal with learning that two datomic entities actually represent the same entity. then later learning that that was an error
00:35	Sgeo	@mail `fogus If I buy your book from B&N, how do I get the ePub version?
00:35	Sgeo	What's the correct command?
00:45	xeqi	$mail Sgeo maybe this one?
00:45	lazybot	Message saved.
00:46	Sgeo	Thanks
00:46	Sgeo	$mail `fogus I bought your book on B&N. Is it possible, from that, to get the ePub version? (Preferably before the physical book arrives, because it might be a while due to hurricane)
00:46	lazybot	Message saved.
01:04	S11001001	Sgeo: if you mean joy, you need the code in the leaflet in the physical book
01:05	S11001001	Sgeo: also, there's a major sale on manning.com for next few days; buy direct from them and it adds to your account right when you buy
01:07	Sgeo	S11001001, too late
01:07	S11001001	Sgeo: today and tomorrow dead trees (including ebook), tuesday ebooks, wednesday everything
01:07	Sgeo	lazybot, mail
01:07	S11001001	Sgeo: can't cancel an order on bn?
01:07	Sgeo	S11001001, I can, but why bother?
01:07	Sgeo	S11001001, also, easier for me to pay for stuff on B&N than elsewhere (long story)
01:08	S11001001	Sgeo: to be able to get the ebook right away
02:47	Sgeo	Does forcing a lazy sequence mutate stuff?
02:47	Sgeo	Suppose I have (def nums (range))
02:47	Sgeo	I do something like (doseq [i nums] (println i))
02:48	Sgeo	Hmm, bad example
02:48	Sgeo	(def nums (range some-really-large-number-such-that-holding-onto-the-entire-seq-at-once-will-run-out-of-memory-but-the-number-itself-isnt-that-big))
02:48	Sgeo	(doseq [i nums] (println i))
02:48	Sgeo	When everything is done printing, will I have run out of memory?
02:49	Sgeo	Or will nums be not forced?
02:52	tomoj	if nums isn't forced, what would print?
02:53	tomoj	you will run out of memory
02:55	tomoj	#'nums holds a reference to the head of the seq, so none of the seq can be garbage-collected
02:56	tomoj	http://programming-puzzler.blogspot.com/2009/01/laziness-in-clojure-traps-workarounds.html
02:56	tomoj	that is interesting in comparison to rx
02:56	tomoj	reminiscent of hot vs cold observables
03:13	Sgeo	rx?
03:15	scottj	Sgeo: probably reactive extensions on .net
03:18	tomoj	and/or js
04:49	sheldonels	is there a way to recurse without naming a function? like, to just recall the function you're in at the moment
04:50	rodnaph	sheldonels: recur?
04:54	Sgeo	sheldonels, ##(doc loop)
04:54	Sgeo	Oh, you probably want recur
04:54	Sgeo	Ignore me
04:54	Sgeo	But the two go togethre
04:54	Sgeo	together
04:54	Sgeo	But you can recur without loop
04:54	Sgeo	Ok, I'm shutting up.
04:55	sheldonels	heh, no worries
04:55	sheldonels	been reading about recur since rodnaph mentioned it, the docs are above my functional grade I think
04:56	sheldonels	both the explanation on special forms and the examples are confusing, but I think I'll get it eventually
04:57	rodnaph	sheldonels: u don't have to think about special forms any differently than functions, it's just an implementation detail.
04:58	Sgeo	rodnaph, that... seems like that could cause some harm, saying that
04:59	sheldonels	ok, not sure I'll grasp this without some help, the docs say (recur exprs*)
04:59	sheldonels	Evaluates the exprs in order, then, in parallel, rebinds the bindings of the recursion point to the values of the exprs.
04:59	Sgeo	sheldonels, first: Do you know what tail-call recursion means?
04:59	sheldonels	is this like saying recur can mutate the things passed into the function above it?
04:59	sheldonels	not really
05:00	rodnaph	Sgeo: well, maybe "don't worry about it for now" is better advice.
05:00	sheldonels	I know clojure doesn't do it fully as a result of the jvm, and that other lisps do
05:00	Sgeo	rodnaph, that seems like it would be better for special forms v. macros
05:00	sheldonels	heh, I'm ok with that, if it's something for later, for now I should just name my functions for recursion purposes
05:00	rodnaph	yes, i almost said macros, but that would have probably just led to more questions, when it wasn't what was trying to be understood. but anyway...
05:01	Sgeo	Let's pretend for the moment that Clojure has it
05:01	Sgeo	And I want to define a factorial function
05:01	sheldonels	ok
05:01	Sgeo	(defn factorial [n] (* n (factorial (dec n))))
05:01	sheldonels	yep
05:01	Sgeo	(dec is a function that returns its argument - 1
05:02	Sgeo	When I call (factorial 5), it needs to do (* 5 (factorial 4))
05:02	sheldonels	like -- in imperative langs, yep
05:02	Sgeo	And that factorial 4 needs to do 4 * factorial 3
05:02	Sgeo	And so forth
05:02	sheldonels	gotcha
05:02	Sgeo	None of these can return until the one at the bottom returns
05:02	Sgeo	Oh, pretend that (factorial 0) returns 1, forgot to do that lol
05:02	sheldonels	yep, so it's kinda like a stack of function calls
05:02	Sgeo	Yes.
05:03	sheldonels	and the stack has to get bigger with each recursion
05:03	Sgeo	Yes.
05:03	sheldonels	until some limit
05:03	Sgeo	So, with a large enough n, my function will crash.
05:03	sheldonels	or your computer explodes :)
05:03	Sgeo	And will use a lot of memory even if it doesn't crash.
05:03	sheldonels	yep, the usual worry with recursion style programming
05:03	Sgeo	Now, let's define factorial differently:
05:04	Sgeo	(Pretending that Clojure has tail-call optimization, which it doesn't)
05:04	Sgeo	(defn factorial [acc n] (if (== n 0) acc (factorial (* acc n) (dec n))))
05:05	Sgeo	Let's look at what happens with (factorial 1 2)
05:06	Sgeo	It will call (factorial (* 1 2) (dec 2)), which is (factorial 2 1)
05:06	Sgeo	And the function will return that
05:06	Sgeo	But since the function is going to return that, if Clojure was smart, it doesn't need to keep track of where it's coming from
05:06	Sgeo	The stack of function calls doesn't need to grow
05:07	Sgeo	Does this make sense?
05:07	sheldonels	kinda, just mulling over the brackets a bit still
05:08	sheldonels	in your example, you're calling 1 2
05:08	sheldonels	why is 1 there as well
05:08	Sgeo	It's the accumulator, the trick I'm using in order to avoid needing to grow the function stack
05:09	Sgeo	When n is 0, I just return the accumulator, which will be the answer.
05:09	sheldonels	right, a way to sum up each step
05:09	Sgeo	Well, multiply up each step, but yes
05:10	sheldonels	and that's the key to avoiding needing to keep track of each step in a stack right, cause it's a passed along value
05:10	sheldonels	think I got it
05:10	Sgeo	:)
05:10	sheldonels	actually, still not sure how that form wouldn't have a stacked effect
05:11	sheldonels	it still needs to call over and over right
05:11	sheldonels	and wait for the 0 condition it unwind
05:11	Sgeo	It is getting called over and over, but since the result of the call is the result of the function, it doesn't need to bother storing where it's calling from
05:12	Sgeo	There's no multiplication that it still needs to do as it unwinds, so it doesn't need to bother with growing the stack
05:12	sheldonels	right
05:12	sheldonels	gotcha
05:12	Sgeo	Tail-call optimization refers to whether the language is smart enough to detect this. Clojure is not.
05:13	Sgeo	However, Clojure provides a form called recur, that you would use in place of that inside factorial call
05:13	Sgeo	(defn factorial [acc n] (if (== n 0) acc (recur (* acc n) (dec n))))
05:14	sheldonels	makes a whole lot more sense now, thanks
05:14	Sgeo	You're welcome
05:15	sheldonels	so using recur is a good idea whenever you can if I'm reading the docs right, as it's the only non stacked recursion available?
05:15	Sgeo	But note that you can ONLY use recur in places where it will be the return value of the enclosing ... function or loop form.
05:15	Sgeo	sheldonels, there's another form of non stacked recursion, but it's more annoying to use
05:15	sheldonels	heh, fair enough
05:16	sheldonels	I'm ok with skipping the annoying parts :)
05:16	Sgeo	Well, if you're interested, look up trampoline
05:16	Sgeo	It does things you can't do with recur
05:20	Sgeo	And with recur you should probably look at loop
05:20	sheldonels	will do
05:20	sheldonels	it's quite a tough thing at first, all this recursion. my first time learning a functional language. so used to imperative style stuff.
05:21	Sgeo	I should note that often you can avoid using recur, since there are easier ways to loop. recur is mainly for when you need explicit recursion, there are functions that are implemented using it but are easier to use than using recur directly.
05:21	sheldonels	in your 2nd example using recur, the named fn wouldn't necessarily need a name right? recur can just work out to rerun the function/loop it's in?
05:22	sheldonels	sure, I've been working through 4clojure.com to try learn
05:22	Sgeo	Right
05:22	sheldonels	I think they purposefully are sidestepping those easier ways to help the learning process
05:22	sheldonels	like some of the questions disallow certain functions that would make the answers trivial
05:23	sheldonels	I'm about to try do a function to count the things in a sequence, going to see if I can do it with recur now
05:23	Sgeo	Awesome
05:23	Sgeo	After you do that, see if you can find a way to do it without recur.
05:29	sheldonels	heh, no luck working it out, maybe without recur will be easier
05:30	rodnaph	does anyone know with aleph, if i can use a single (wrap-ring-handler) for all my compujure routes, or if it needs to be done once for each route. doesn't seem to work, but wanna see if that i'm doing should work befroe investigating further...
05:32	Sgeo	sheldonels, hmm.
05:32	sheldonels	yep, got it
05:32	hiredman	rodnaph: a single wrap-ring-handler should work, but it tends to eat exceptions, so you should wrap your routes in something that deals with them somehow (prints them out or whatever)
05:32	sheldonels	named functions I guess are easier for my tiny brain!
05:32	sheldonels	why is recursion so hard, stupid thing
05:32	sheldonels	heh
05:33	sheldonels	with recur, I'm getting a "Can only recur from tail position"
05:33	Sgeo	sheldonels, you can't try to "do stuff" like multiply the result of a recur
05:34	sheldonels	is that cause of similar to your first factorial example, I can't use this construct unless the value it returns doesn't get reused in the function it's called from?
05:34	Sgeo	It can only go back up to the enclosing function or loop
05:34	sheldonels	right
05:34	Sgeo	sheldonels, yes
05:35	sheldonels	is the factorial example doable with recur without an accumulator? I don't think so, just checking
05:35	Sgeo	I don't believe so
05:46	sheldonels	no luck with the recur version, I need an accumulator, but can't default it to 0 it seems
05:46	sheldonels	if I make it optional, then I get a really weird error
05:46	sheldonels	and default makes it mismatch the argument count
05:46	sheldonels	I guess recur can only do runtime matching arguments
05:48	sheldonels	anyone know why I would be getting this error? https://gist.github.com/3968185
05:50	rodnaph	looks like the destructuring is causing problems as you recurse maybe?
05:51	sheldonels	I'm not even seeing a long anywhere there, is it something internal as part of recur maybe?
05:51	rodnaph	or the (next l) actually. l is a long correct?
05:52	rodnaph	`(next [1 2 3])
05:52	sheldonels	a list
05:52	rodnaph	oops
05:52	sheldonels	the idea is to count the items in the list
05:52	sheldonels	using an accumulator so that I can recur
05:52	rodnaph	yah, but (next 1) doesn't make sense (and will give that error)
05:53	rodnaph	(next) needs to take a collection, not a single long
05:53	sheldonels	right, I thought (next '(1 2 3)) gives '(2 3)
05:53	rodnaph	yes it does
05:53	sheldonels	l is my list I think, unless I messed up the syntax somewhere
05:53	sheldonels	(next l) should be l minus 1 item
05:54	rodnaph	well, l is not a list in some call (that's what the error is saying)
05:54	sheldonels	right, I see
05:54	sheldonels	thanks :)
05:57	sheldonels	ah well, I give up, at least I got it working without recur
05:58	sheldonels	thanks for all the help rodnaph, Sgeo. cya around.
05:58	rodnaph	good luck!
06:10	andrewmcveigh	&(= (
06:10	lazybot	java.lang.RuntimeException: EOF while reading, starting at line 1
06:10	andrewmcveigh	(fn c [l & [a]] (if l (recur (next l) (+ (if a a 0) 1)) 0))
06:10	andrewmcveigh	'(1 2 3 3 1)) 5)
06:11	andrewmcveigh	&((fn [l & a] (if l (recur (next l) (+ (if a a 0) 1)) a)) '(1 2 3 3 1))
06:11	lazybot	⇒ 5
06:20	samrat	tab-completion isn't working with emacs-live + evil-mode. Any ideas on how to fix it?
07:02	rodnaph	trying to create a websocket server with aleph - can anyone help?
07:48	mklappstuhl	gfredericks, any advice regarding my question from yesterday?
07:50	mklappstuhl	I want to simulate a fictional stock portfolio and I'm wondering which data structures to use to create the portfolio...
07:50	mklappstuhl	I have some ideas here: https://github.com/mklappstuhl/computational-investing.clj/blob/master/src/mklappstuhl/stock_utils/simulate.clj
07:50	mklappstuhl	Any feedback would be greatly appreciated :
08:34	mklappstuhl	I want to simulate a fictional stock portfolio and I'm wondering which data structures to use to create the portfolio...
08:34	mklappstuhl	I have some ideas here: https://github.com/mklappstuhl/computational-investing.clj/blob/master/src/mklappstuhl/stock_utils/simulate.clj
08:34	mklappstuhl	Any feedback would be greatly appreciated :)
09:44	sheldonels	((fn f [x] (if x (conj (rest x) (first x)) nil)) '(1 2 3 4)) trying to switch around rest and first to reverse the list, conj doesn't work with the first param being an item rather than a collection, anyone know of something I can use to get a new item added to a collection at the far end?
09:59	AimHere	sheldonels, you could just use the reverse function
10:02	AimHere	Oh, he's gone
10:29	ambrosebs	If anyone was thinking of contributing to Typed Clojure, some small jobs https://github.com/frenchy64/typed-clojure/wiki/Small-Jobs
10:43	edmund__	ambrosebs: was reading your dissertation this am. Very nice work.
10:44	edmund__	its a nice way for me to learn about this whole typing jiggery-poke
10:44	ambrosebs	edmund_: thanks!
10:44	ambrosebs	ditto for me :)
10:45	ambrosebs	Learnt a lot this year hehe
10:45	ambrosebs	How are you finding it? Any confusing bits?
10:46	ambrosebs	I didn't get a chance to run it by anyone but my supervisor...
10:46	ambrosebs	I can still correct it before December.
10:47	edmund__	well, I'm not academically able in CS
10:47	edmund__	but this is good as the new concepts you introduce are clear to me
10:48	edmund__	i did have a question on listing 1.9
10:48	ambrosebs	The target audience is basically people familiar with popular programming languages.
10:48	edmund__	the (if a a 0)
10:49	ambrosebs	yep
10:49	ambrosebs	just a regular if?
10:49	edmund__	should it be (if a a nil) perhaps
10:49	ambrosebs	look at the return type of num-vec2
10:49	tmciver	ambrosebs: where can one read this dissertation?
10:49	edmund__	the else branch returns a nil and you say that the type of the else branch collapses (U nil Number) to nil
10:50	edmund__	whereas 0 is Number
10:50	edmund__	I'm probably being dumb though :)
10:51	ambrosebs	ah it's a bit hard to read.
10:52	ambrosebs	Similarly, following the else branch refines the type of -->"a"<-- to nil from (U nil Number)
10:52	edmund__	aaaaaaaah
10:52	edmund__	yes
10:52	tmciver	ambrosebs: Ah, was looking for your disseration; found it.
10:52	edmund__	not the type of the function
10:52	edmund__	quite right ;)
10:52	ambrosebs	tmciver: cool, corrections welcome!
10:53	edmund__	i'm confused about the ... type
10:53	ambrosebs	edmund__: I'll reword it.
10:53	edmund__	but that needs further work from me :)
10:53	ambrosebs	edmund__: where does it come up first?
10:53	ambrosebs	Listing 1.8?
10:54	edmund__	pg 11
10:54	edmund__	yeah 1.8
10:54	edmund__	i just need to digest a bit what it meas
10:54	edmund__	s/meas/means
10:54	ambrosebs	yea, it's tough to get your head around it at first.
10:54	edmund__	and how Type b ... b interacts with Type a
10:55	edmund__	all new stuff to me
10:55	ambrosebs	I don't think there's anything notable about that interaction.
10:55	edmund__	what would be uber cool for the Conj is if you gave a handson session where we go through some examples of using TC
10:56	edmund__	i imagine your talk will be more technically focussed
10:56	ambrosebs	the interesting bit is between b ... b and (U nil (Seqable b)) ... b
10:56	edmund__	yeah, let me think about that for a bit and get back to you with questions
10:56	edmund__	but, this is really interesting work and something that I hope you continue with
10:56	edmund__	you doing further studies ?
10:57	ambrosebs	I still haven't worked out exactly what I'm talking on. But my Conj proposal says I'm talking about practical features.
10:57	edmund__	aaah well, in that case :)
10:57	edmund__	its always easier to reason from concrete to abstract
10:57	ambrosebs	I'm giving an Unsession talk on the theory.
10:58	ambrosebs	which is the day after
10:58	edmund__	perfect: pretty exciting stuff.
10:59	ambrosebs	I know right! ;)
10:59	edmund__	i still have to get my talk into any sort of shape. EEEP
11:01	ambrosebs	I'm giving a 20m seminar on Thursday for my degree. Hopefully will kickstart the work (although writing a dissertation sure helps)
11:01	edmund__	good luck with that - you'll kill
11:01	ambrosebs	:)
11:04	user	test
11:06	edmund__	user: pass
11:06	user	:)
11:29	solussd	I've been playing around with Clojure-py the past couple of days. Any insight on why it appears to be about 20x slower than python?
11:31	goracio	hi ther here is the problem - i try (def thing (func)) func takes some time to do stuff and then i use thing and it appears unbound - how to handle this stuff ?
11:38	goracio	so any thoughts ?
11:38	solussd	goracio: could you upload the actual usecase to refheap?
11:40	goracio	solussd: well it's pretty simple - i want define thing and then use it but to defining thing takes some time so when i use it compiler says that it is ubound
11:41	solussd	goracio: it shouldn't be, so there must be something weird going on in your code. :)
11:41	goracio	solussd: so function took some time to execute and it appears that thing wasn't defined cause compiler doesn't wait
11:43	goracio	solussd: for example (def thing (func)) will compiler wait for results that func will return or may be will not ever
11:44	solussd	so, does this leave blah unbound? : (def blah (#(do (Thread/sleep 5) "hi")))
11:44	solussd	it will wait
11:45	goracio	hmm
11:45	tmciver	goracio: I had a problem like this when trying to def a var to a jetty server. But since the 'create server' function never really returns (the server is running), the server var was unbound. I think you simply can't use the var until the function returns. Perhaps you need a Future, or something.
11:47	goracio	tmciver: yes func is communicating with the db server and waits results from it but func is returning something for sure
12:58	erwagasore	I am using require instead of use in my namespace, something like this : (ns mynamespace (:require [ring.adapter.jetty :refer [run-jetty]]))
12:59	erwagasore	Is something like this possible: (ns mynamespace (:require [ring.util.response :refer :all :exclude [not-found]])
12:59	erwagasore	?
13:09	erwagasore	or something like this: (ns mynamespace (:require [ring.util.response :refer :all [not-found :as nf]]))
14:22	TimMc	I think there might be a rename...
14:23	TimMc	Maybe that's only with use.
14:32	devn	Anyone know where (raise) went in clojure.contrib.condition? Is there an analagous form in slingshot?
15:10	hyPiRion	TimMc: Yeah, there's rename
15:11	hyPiRion	&(require '[clojure.pprint :refer [cl-format] :rename {cl-format fmt}])
15:11	lazybot	⇒ nil
15:11	hyPiRion	&(fmt true "~{~A~^, ~}~%" [1 2 3])
15:11	lazybot	⇒ 1, 2, 3 nil
15:25	hiredman	dnolen: does the clojurescript compiler (outside of google closure) do any constant propagation? I am seeing (def ^:export m 1) (defn f [] (g m)) turn 'm' in to the constant 1 in the generated js
15:25	hiredman	which means I cannot fiddle the exported value m and get a different result
15:30	dnolen	hiredman: it does not, that would be gclosure
15:30	dnolen	hiredman: I think you'll see that with even simple optimizations
15:32	tomoj	is there a problem doing `:where [$a _ :foo ?foo-a] [(foo ?foo-a) ?foo)] [$b _ :foo ?foo-b] [(foo ?foo-b) ?foo]` ?
15:34	hiredman	dnolen: that is kind of a drag
15:36	tomoj	shouldn't it be ^:dynamic ?
15:36	tomoj	(and would that make a difference?)
15:40	gfredericks	tomoj: probably depends on if it makes a difference in the generated JS, rather than just compiler warnings
15:42	dnolen	hiredman: yeah it's annoying, perhaps it can be defeated w/ a JS object? (def ^:export props (jsobj "m" 1)) ?
15:47	hiredman	dnolen: I'll try that next time
15:50	gfredericks	if the jsobj idea didn't work that would say bad things about the correctness of atoms I would think
15:51	dnolen	hiredman: hmm there's probably a way for us to avoid ugly hacks like that if we expose more hooks to closure annotations http://developers.google.com/closure/compiler/docs/js-for-compiler
15:52	dnolen	hiredman: ^:expose I think
15:55	hiredman	dnolen: maybe :export should just imply expose
15:57	dnolen	hiredman: that might be true, http://dev.clojure.org/jira/browse/CLJS-410
16:08	tomoj	seems joining on the output of a db fn like that is O(n^k)
17:20	mklappstuhl	I want to simulate a fictional stock portfolio and I'm wondering which data structures to use to create the portfolio...
17:20	mklappstuhl	I have some ideas here: https://github.com/mklappstuhl/computational-investing.clj/blob/master/src/mklappstuhl/stock_utils/simulate.clj
17:20	mklappstuhl	Any feedback would be greatly appreciated :)
17:21	mklappstuhl	basically I try to wrap "buy" functions in a list...
17:21	mklappstuhl	But I think there might be better tools in clojure to do it ..
17:26	technomancy	huh: https://twitter.com/atosborne/status/180246603586736128
17:30	etherealG	what's the difference between sequential and iseq?
17:30	amalloy	&(map (juxt sequential? seq?) '[[1 2 3] (1 2 3)])
17:30	lazybot	⇒ ([true false] [true true])
17:31	amalloy	technomancy: isn't that just optimizing refer :all? i can see it speeding up the refer-clojure that happens in every namespace, but not much else. given that, why not just cache the mappings for clojure.core, and have it take roughly zero time for the case that's actually slow?
17:31	frio	&(sequential [1 2 3 4 4])
17:31	lazybot	java.lang.RuntimeException: Unable to resolve symbol: sequential in this context
17:31	frio	&(sequential? [1 2 3 4 4])
17:31	lazybot	⇒ true
17:32	frio	hrm
17:33	bbloom	in short: sequential means it has a well defined order. It's a sequence if it's a head/tail cons-style data structure, and "seqable" implies that it can be coerced to a sequence via the seq function
17:33	bbloom	vectors are sequential, but not sequences
17:33	bbloom	lists are sequential and are actually sequences
17:33	technomancy	amalloy: yeah, probably makes more of a difference with :refer :all
17:34	amalloy	technomancy: no, i mean it looks to me like that code is only used at all for refer/all
17:34	etherealG	gotcha, so sequential? is the right thing to use for code that you want to be collection agnostic?
17:34	etherealG	if you need to check the incoming data for being able to do things like filters etc.
17:35	amalloy	if you need to filter, just call filter and break if an exception happens
17:35	technomancy	you can filter over lots of nonsequentials
17:36	bbloom	etherealG: generally, you simply coerce to a sequence and test against nil
17:37	bbloom	etherealG: er, sorry, misunderstood your question, yeah, you're right
17:37	Sgeo	,(for [[k v] {:a 1 :b 2}] [v k])
17:37	clojurebot	([1 :a] [2 :b])
17:38	bbloom	,(seq {:a 1 :b 2})
17:38	clojurebot	([:a 1] [:b 2])
17:38	bbloom	,(sequential? {:a 1 :b 2})
17:38	clojurebot	false
17:38	bbloom	etherealG: see that ^^ maps aren't sequential, but they are seq-able
17:39	bbloom	some canonical linearization of maps exists :-)
17:39	Sgeo	,(seq {:a 1 :b 2})
17:39	clojurebot	([:a 1] [:b 2])
17:39	Sgeo	hmm
17:40	Sgeo	,(find [2 1 0] 0)
17:40	clojurebot	[0 2]
17:40	Sgeo	awesome
17:40	Sgeo	,(class (find [2 1 0] 0))
17:40	clojurebot	clojure.lang.MapEntry
17:42	amalloy	&(-> (iterate #(find % 0) [0 0]) (nth 1000))
17:42	lazybot	⇒ [0 0]
18:05	dnolen	bbloom: hrm, it seems like we still have some let cases to address? http://dev.clojure.org/jira/browse/CLJS-411
18:06	bbloom	dnolen: give me a moment & i'll take a look
18:08	bbloom	neither of those throw an assertion error for me
18:09	bbloom	dnolen: what's the problem exactly?
18:14	ForSpareParts	If I compile some Clojure AOT using gen-class, will I still be able to do REPL-state stuff with the compiled code? Say, accessing def'd stuff in the clojure code that Java is invoking?
18:16	ForSpareParts	And a related question: what's the best way to pull data out of a Clojure map (with flexible structure) in Java code? I'd rather not have a chain of type casts several lines long, but I'm also a little concerned that using the RT package would have performance implications
18:16	ForSpareParts	(I'm trying to make a simple game, and parsing/compiling on every line seems like a bad choice)
18:40	AtKaaZ	is there a git library for clojure?
18:40	AtKaaZ	if not, what would be the way to run a command and get back its output?
18:41	AdmiralBumbleBee	conch is good for that
18:41	AdmiralBumbleBee	no idea if there's a git library
18:42	AtKaaZ	thank you, I'll check that
18:43	tomoj	codeq just uses Runtime.exec :O
18:44	Apage43	https://github.com/clj-jgit/clj-jgit
18:45	AtKaaZ	hmm, I'm getting cannot resolve dependency conch/conch , maybe I'll try using Runtime.exec
18:45	tomoj	it's just conch
18:46	tomoj	https://clojars.org/conch
18:46	amalloy	tomoj: conch is an alias for conch/conch; that's what lein does if you omit a groupid
18:46	AtKaaZ	yeah but that's what it says, probably resolves to that when namespace not specified
18:46	tomoj	orite
18:46	AtKaaZ	wait, do I need the clojars plugin?
18:47	AtKaaZ	or lein knows to look there
18:47	dnolen	bbloom: you're right, not a problem
18:47	bbloom	dnolen: good news! the unmanaged vars really do look nice huh? :-)
18:48	dnolen	bbloom: they do :)
18:48	amalloy	AtKaaZ: you could try jgit, though i don't know how easy it is to use
18:50	AtKaaZ	don't mind if I'll give it a try
19:00	AtKaaZ	amalloy: this seems useful: https://github.com/clj-jgit/clj-jgit
19:01	bbloom	dnolen: i might be doing something wrong, but i've got a relatively simple cljs-build setup going on and i'm getting a warning trying to use defprotocol
19:01	bbloom	WARNING: Use of undeclared Var cps/-return at line 3 src/cps.cljs
19:01	bbloom	where line 3 is the -return form here:
19:01	bbloom	(defprotocol IContinuation
19:01	bbloom	(-return [_ result])
19:01	bbloom	(-raise [_ error]))
19:01	bbloom	any ideas what might be causing that?
19:03	amalloy	bbloom: related to return being a javascript keyword?
19:03	bbloom	amalloy: i thought that might be it, but the - is converted to a _ also the next line gives a similar warning:
19:03	bbloom	WARNING: Use of undeclared Var cps/-raise at line 3 src/cps.cljs
19:03	bbloom	raise isn't a keyword
19:13	dnolen	bbloom: hmm I don't know.
19:14	dnolen	bbloom: it's only supposed to issue that warning if it encounters a symbol that hasn't been declared or def'd
19:14	bbloom	dnolen: could it have something to do with a cli (non cljs) namespace of the same name?
19:15	dnolen	bbloom: oh hmm, it looks like you've aliased a namespace to cps and are using -return in a different namespace?
19:16	dnolen	bbloom: if so it should have analyzed the other namespace first and picked up those protocol definitions
19:16	bbloom	dnolen: i have cps.clj and cps.cljs -- the former for compile time & macros, the later for runtime stuff
19:16	dnolen	bbloom: so is cps/-raise something emitted by the macro?
19:16	bbloom	dnolen: nope
19:17	bbloom	dnolen: https://github.com/brandonbloom/cljs-cps/
19:18	bbloom	dnolen: if you look at the bottom of cps.clj, you'll see all my compile time tests… i've started on test.cljs, which is going to be the runtime tests
19:18	bbloom	dnolen: you'll also see how pretty an AST transform can be :-)
19:19	dnolen	bbloom: yes that looks pretty cool. dunno about the issue tho, minimal case would be helpful.
19:19	dnolen	bbloom: I would look more closely myself but busy w/ some other things atm.
19:19	bbloom	ok, ill try to figure it out
19:19	bbloom	i've got to run now
20:06	AtKaaZ	type hint for array of String?
20:07	AtKaaZ	I hope it's not this {:tag "[Ljava.lang.String;"}
20:13	Sgeo	,(class (string-array))
20:13	clojurebot	#<CompilerException java.lang.RuntimeException: Unable to resolve symbol: string-array in this context, compiling:(NO_SOURCE_PATH:0)>
20:13	Sgeo	,(class (object-array))
20:13	clojurebot	#<ArityException clojure.lang.ArityException: Wrong number of args (0) passed to: core$object-array>
20:13	Sgeo	,(class (object-array 0))
20:13	clojurebot	[Ljava.lang.Object;
20:13	Sgeo	...what
20:13	Sgeo	I have no idea what's going on
20:29	dnolen	AtKaaZ: that is correct, ^"[Ljava.lang.String;"
20:29	AtKaaZ	yep thanks
20:31	wingy	the Java interop comes handy dealing with external services who only have Java SDK
20:32	wingy	how do i use maven projects in my project.clj?
20:40	amalloy	same way you use clojure projects, which are published via maven
20:41	akhudek	wingy: just add to the dependencies something like [group-id/artifact-id "version"]
20:41	akhudek	if the group and artifact id are the same, like for many clojure projects, you can just use [artifact-id "version"]
20:46	wingy	akhudek: it says i have to add their repository at http://x.github.com/x/releases
20:46	dnolen	bbloom: ok, I bendlas found a legitimate issue http://dev.clojure.org/jira/browse/CLJS-411
20:47	akhudek	wingy: you can specify extra repositories in lein with :repositories (see https://github.com/technomancy/leiningen/blob/preview/sample.project.clj#L161)
20:49	wingy	akhudek: ok thx
20:58	bendlas	bbloom: hi I had wondered about your IRC handle
20:58	bendlas	dnolen: yeah, sorry for the miscommunication
21:00	meredydd	Hey
21:01	meredydd	Anyone around and interested in giving me feedback on a new function-call mocking library?
21:01	meredydd	github.com/meredydd/expect-call
21:01	meredydd	(Hmm, that's not clickable in XChat. http://github.com/meredydd/expect-call)
21:16	AtKaaZ	,(assert false)
21:16	clojurebot	#<RuntimeException java.lang.RuntimeException: java.lang.AssertionError: Assert failed: false>
21:17	AtKaaZ	does this work regardless of the -ea jvm option?
21:17	AtKaaZ	in other words, is it unlike the assert used in java?
21:18	AtKaaZ	I believe the answer is yes but still, I'd prefer this to be documented
21:23	amalloy	&(macroexpand-1 '(assert false))
21:23	lazybot	⇒ (clojure.core/when-not false (throw (new java.lang.AssertionError (clojure.core/str "Assert failed: " (clojure.core/pr-str (quote false))))))
21:30	TimMc	The question is really whether Clojure assertions are enabled iff Java assertions are enabled at macro-expand time.
21:31	Sgeo	(source assert)
21:31	Sgeo	&(source assert)
21:31	lazybot	java.lang.RuntimeException: Unable to resolve symbol: source in this context
21:31	Sgeo	,(source assert)
21:31	clojurebot	Source not found
21:31	TimMc	,(apropos 'source)
21:31	clojurebot	(source-path source source-fn resource)
21:32	TimMc	,(apropos 'assert) bah
21:32	clojurebot	(assert assert)
21:32	AtKaaZ	&clojure-version
21:32	lazybot	⇒ {:major 1, :minor 4, :incremental 0, :qualifier nil}
21:32	gfredericks	TimMc: it's based on the assert var, ain't it?
21:32	AtKaaZ	&(use 'clojure.repl)
21:32	lazybot	⇒ nil
21:33	AtKaaZ	&(source source)
21:33	lazybot	⇒ Source not found nil
21:33	Sgeo	http://clojuredocs.org/clojure_core/clojure.core/assert
21:33	Sgeo	It only returns code when assert is truthy
21:34	gfredericks	(set! assert :falsy)
21:34	AtKaaZ	,(binding [assert false] (assert false))
21:34	clojurebot	#<RuntimeException java.lang.RuntimeException: java.lang.AssertionError: Assert failed: false>
21:34	gfredericks	AtKaaZ: it was truthy at compile-time
21:35	Sgeo	The binding occurs at runtime, but the macro is expanded at macroexpand time
21:35	AtKaaZ	makes sense
21:35	gfredericks	you can (binding [assert false] (eval '(assert false)))
21:35	Sgeo	,(alter-var-root #'assert (constantly false)) (assert false)
21:35	clojurebot	#<Exception java.lang.Exception: SANBOX DENIED>
21:36	AtKaaZ	,(binding [assert false] (eval '(assert false)))
21:36	clojurebot	#<Exception java.lang.Exception: SANBOX DENIED>
21:36	AtKaaZ	oh right, eval
21:36	gfredericks	what happens if you take a val and put it on computers?
21:37	AtKaaZ	the computer believes?
21:37	gfredericks	no, you get an e-val!
21:37	AtKaaZ	nice
21:48	callen	you know, I put up a pull request fixing that irritating SANBOX DENIED typo ages ago
21:50	AtKaaZ	in what way?
21:51	AtKaaZ	oh i see, typo :)
22:01	TimMc	callen: I've grown fond of it.
22:09	jimduey	Sgeo: Hi
22:12	Sgeo	Hi jimduey
22:13	jimduey	Saw your comment about m/do being a macro.
22:13	jimduey	I was actually pleased that it was the only one I needed to be a macro. :)
22:13	jimduey	And that's because it deals with binding values to symbols, which can only be done using a macro.
22:13	Sgeo	Actually, the thing with it is that its name is the same as the name of a special form
22:14	jimduey	Ah. That I understand.
22:14	Sgeo	Which means you can't actually use it in, you can only refer to it with a qualified name, either fully qualified or alias, like m/do
22:14	jimduey	Good point.
22:16	TimMc	OK, what's the point of this? https://github.com/clojure/clojure/blob/master/src/clj/clojure/main.clj#L85
22:16	jimduey	Not sure what else to call it, since 'do notation' is the term in Haskell.
22:16	jimduey	Regardless, thanks for carrying the monad flag in Clojure land. :)
22:16	TimMc	(binding [foo foo] ...) seems like a no-op -- is there a point to creating a new dynamic scope level?
22:17	Sgeo	http://ideone.com/JQz5VF
22:17	Sgeo	jimduey, you're welcome
22:18	Sgeo	A way to get special forms to be namespaced like the rest of clojure.core would be nice
22:23	Sgeo	I really should work on fixing delimc
22:23	Sgeo	Although I think it might be harder than I originally thought
22:23	Sgeo	I forgot how I came to that conclusion though
22:26	tomoj	what's wrong with delimc?
22:27	Sgeo	tomoj, it doesn't work unless you use it, bringing all its symbols directly into the current namespace
22:27	Sgeo	Due to it being a port from CL -> Clojure, and the subtle difference between CL symbols and Clojure symbols+namespaces
22:28	Sgeo	There might be more issues due to that difference, I'm not sure
22:28	Sgeo	Erm, Clojure symbols+vars
22:28	tomoj	I see
22:31	jimduey	If you do :exclude some symbols from clojure.core, you can always get at them again by fully qualifying their names. clojure.core/do etc.
22:33	Sgeo	jimduey, the point is that :exclude on do flat out does not work.
22:33	Sgeo	An unqualified do always refers to the core do, under all circumstances.
22:34	jimduey	so it is. I'll just hang up my keyboard and go to bed now. :)
22:38	ivan	<Sgeo> An unqualified do always refers to the core do, under all circumstances. <- only in list head position, maybe obvious
22:38	Sgeo	Oh, erm, yes
22:38	Sgeo	,(let [do 5] (do do))
22:38	clojurebot	5
22:38	gfredericks	is (do do) ever not funny??
22:38	lazybot	gfredericks: What are you, crazy? Of course not!
22:38	Sgeo	,(let [+ 5] (+ +))
22:38	clojurebot	#<ClassCastException java.lang.ClassCastException: java.lang.Long cannot be cast to clojure.lang.IFn>
22:40	gfredericks	,(let [+ partial] (+ + + + + + + +))
22:40	clojurebot	#<core$partial$fn__2495 clojure.core$partial$fn__2495@39ff48d8>
22:43	callen	TimMc: ugh.
22:48	muhoo	wait, how is that even possible
22:48	muhoo	,(5 5)
22:48	clojurebot	#<ClassCastException java.lang.ClassCastException: java.lang.Long cannot be cast to clojure.lang.IFn>
22:48	muhoo	right.
22:48	muhoo	,(let [do 5] (do do))
22:48	clojurebot	5
22:48	muhoo	????
22:51	Sgeo	muhoo, do is a special symbol
22:51	Sgeo	Unqualified, it always refers to the same thing in head form
22:52	Sgeo	So, the (do do) is the special form do with lexically scoped variable do
22:52	Sgeo	,(special-symbol? 'do)
22:52	Sgeo	&(special-symbol? 'do)
22:52	lazybot	⇒ true
22:54	Sgeo	,(let [-> 5] (-> ->))
22:54	Sgeo	&(let [-> 5] (-> ->))
22:54	lazybot	⇒ 5
22:55	Sgeo	o.O what
22:56	Sgeo	&(let [-> inc] (-> 5))
22:56	lazybot	⇒ 5
22:56	Sgeo	&(special-symbol? '->)
22:56	lazybot	⇒ false
22:57	metellus	,(let [+ -] (+ 5 3))
22:57	Sgeo	&(let [+ -] (+ 5 3))
22:57	lazybot	⇒ 2
22:57	metellus	&(let [inc 5] (inc inc))
22:57	lazybot	java.lang.ClassCastException: java.lang.Long cannot be cast to clojure.lang.IFn
22:58	xeqi	&(let [-> 5] ->)
22:58	lazybot	⇒ 5
23:00	Sgeo	Going to try it at the REPL, maybe clojail's weird?
23:01	Sgeo	user=> (let [-> inc] (-> 5))
23:01	Sgeo	6
23:02	Sgeo	(do do) still does its thing, though
23:03	Sgeo	&clojure-version
23:03	lazybot	⇒ {:major 1, :minor 4, :incremental 0, :qualifier nil}
23:03	Sgeo	Raynes, hello
23:03	gfredericks	lazybot: quit being weird
23:04	Sgeo	It's probably Clojail
23:05	Sgeo	Why is clojurebot broken?
23:05	Sgeo	,5
23:05	xeqi	,asdf
23:06	xeqi	,(5 5)
23:06	xeqi	hmm, muhoo got it to work earlier :p
23:09	gfredericks	&(let [-> 8] ->)
23:09	lazybot	⇒ 8
23:10	gfredericks	&(let [-> :foo] (-> {}))
23:10	lazybot	⇒ {}
23:10	gfredericks	in clojail, all clojure macros are special forms :)
23:11	Sgeo	Yes. As far as I'm concerned, this is a bug.
23:13	AtKaaZ	what's the safest way to make sure a bunch of statements get executed?
23:16	Sgeo	hm?
23:16	clojurebot	benchmarking is https://github.com/hugoduncan/criterium
23:17	AtKaaZ	I guess dorun will do...
23:21	Sgeo	AtKaaZ, what do you mean by "a bunch of statements"?
23:22	AtKaaZ	forms
23:22	AtKaaZ	with side effects
23:23	Sgeo	You don't need to wrap them in anything unless you're doing them in a for otherwise involving laziness
23:23	AtKaaZ	they are in a true branch of an if
23:23	Sgeo	Ah
23:23	AtKaaZ	but I used dorun
23:23	Sgeo	You probably want do
23:24	Sgeo	if takes three things: A test, ONE form for the true branch, and optionally, ONE form for the false branch
23:24	AtKaaZ	just that I was wondering if somehow it would trigger the dorun [n coll] instead of dorun [coll]
23:24	Sgeo	do will let you combine multiple forms into 1 form
23:25	Sgeo	(if true (do (println "Hello") (println "There")) (println "This is in the else"))
23:25	Sgeo	dorun is specifically for realizing lazy collections
23:26	AtKaaZ	what would be the difference between do and dorun there? assuming the first println is something like (.delete fFile)
23:26	AtKaaZ	for some reason I was unsure that do will cause the side effects to happen, but it kind of makes sense, since the forms are evaluated before being passed to the do (so to speak)
23:28	Sgeo	dorun is not intended to group multiple forms together. It is intended to fully realize a lazy sequence and induce any side-effects in that sequence by doing so
23:28	Sgeo	Why do you think that the side effects might not happen
23:31	AtKaaZ	I just cannot imagine all possible variants and therefore I chose to be unsure :) but if do was a macro then I'd be unsure, I guess since it's a function the passed forms are all evaluated prior to executing the do
23:31	AtKaaZ	which returns last
23:31	tomoj	it's not a function
23:31	AtKaaZ	special form?
23:31	tomoj	it's a special form
23:31	AtKaaZ	ok
23:31	AtKaaZ	so in theory it can act like a macro then?
23:32	Sgeo	Yes.
23:32	Sgeo	But macros can evaluate the forms they're given if they choose
23:32	Sgeo	But the do special form always evaluates its forms, assuming that the do itself is evaluated
23:33	AtKaaZ	alright
23:34	AtKaaZ	,(= (ifn? 'do) (special-symbol? 'do))
23:34	clojurebot	true
23:35	zackzackzack	What does the syntax ::foo mean?
23:36	Raynes	&::foo
23:36	lazybot	⇒ :clojure.core/foo
23:36	AtKaaZ	,:foo
23:36	clojurebot	:foo
23:37	AtKaaZ	,::foo
23:37	clojurebot	:sandbox/foo
23:37	zackzackzack	So a namespaced keyword of sorts?
23:39	AtKaaZ	prefixing it with the current namespace
23:39	AtKaaZ	,ns
23:39	clojurebot	#<Namespace sandbox>
23:39	zackzackzack	Ahhh
23:39	zackzackzack	That makes sense
23:42	Sgeo	Oh hey clojurebot's back
23:42	Sgeo	,(let [-> inc] (-> 5))
23:42	clojurebot	6
23:43	Sgeo	I don't think I'm going to forget which one uses Clojail now
23:50	flying_rhino	hello guys
23:51	zackzackzack	flying_rhino, hi
23:53	Raynes	Sgeo: Yeah, I noticed that a while back. Haven't had time to investigate.
23:53	flying_rhino	how 'scriptable' (for lack of a better word) is clojure? For example, I wonder if I can load clojure code as a replacement for XML. I also wonder if I can have REPL inside application, so I can try things out without recompliling.
23:54	Raynes	flying_rhino: You can absolutely have an embedded repl.
23:54	Raynes	You can even run an nrepl server in there and attach/detach from it as you please.
23:54	zackzackzack	,(println "Say hello clojurebot")
23:54	clojurebot	Say hello clojurebot
23:54	Raynes	There is actually a thing, drawbridge I think, for talking to nrepl servers deployed in web apps.
23:55	zackzackzack	flying_rhino, this irc room has an embedded repl named clojurebot
23:55	Raynes	Also lazybot
23:55	Raynes	&(+ 3 3)
23:55	lazybot	⇒ 6
23:57	flying_rhino	can I keep that repl sandoxed so if it crashes it doesn't crash my whole app?
23:57	flying_rhino	some sort of task manager thing where I can kill threads that get stuck?
23:58	zackzackzack	Raynes, clojail would work for that, right?
23:58	zackzackzack	https://github.com/flatland/clojail
23:58	Raynes	I don't think that's the kind of sandboxing he wants.
23:58	zackzackzack	Yeah, you've written it be pretty strong