#clojure – 2010-06-01

2010-06-01

00:23	mebaran151	I'm having some slime trouble
00:23	mebaran151	whenever I try to C-c C-k it fails to compile-file-for-emacs
00:31	Raynes	mebaran151: It fails to find the command?
00:32	mebaran151	wrong number of args passed
00:32	mebaran151	slime starts up, and I can run basic commands, but I can move any clojure from the edit buffer to the repl
00:32	Raynes	Wrong number of args passed to compile-file-for-emacs?
00:32	mebaran151	yep
00:33	mebaran151	wrong number of args passed to basic$eval--986$compile-file-for-emacs
00:33	mebaran151	thrown by a working slime
00:33	Raynes	C-c C-k is bound to slime-compile-and-load-file
00:33	Raynes	Not compile-file-for-emacs.
00:34	Raynes	Try doing M-x slime-compile-and-load-file and see what happens.
00:34	mebaran151	same problem
00:35	mebaran151	actually C-c C-c works
00:36	Raynes	Hrm.
00:36	mebaran151	it got a def
00:36	mebaran151	could it be a mismatch between my slime and clojure versions
00:36	mebaran151	I downloaded clojure-1.2 and I think I'm running swank-clojure-1.2
00:37	Raynes	mebaran151: Are you using leiningen for this project?
00:37	Raynes	The latest version of swank-clojure is 1.2.1.
00:37	mebaran151	right now I'm not using leiningen
00:38	Raynes	Shouldn't be any problems with whatever version of Clojure you're using.
00:38	mebaran151	I just swank-clojure-project to slurp up the jars in my lib dir
00:38	Raynes	mebaran151: I'd suggest asking on the swank-clojure mailing list, perhaps linking to this discussion.
03:07	bozhidar	hey, guys - how can one access the a resource in the resources folder of a lein application?
03:08	bozhidar	in Java I'd do a getResourceAsStream("/the/package/the_resource")
03:08	bozhidar	should I use the same code or is there something more idiomatic?
03:14	tomoj	as far as I know there is nothing more idiomatic
03:14	tomoj	I think something like (.getResourceAsStream (clojure.lang.RT/baseLoader) ...)
03:15	bozhidar	I see
03:17	lessthantristan	yeah, I've always just used the line tomoj suggested. i've never asked about a more idiomatic form tho :)
03:21	bozhidar	lessthantristan: I have nothing against the Java interop, after all I'm a Java dev
03:22	bozhidar	that said I enjoy idiomatic clojure a lot more, when available ;-)
03:33	tomoj	I guess ideally this bit of java interop will be wrapped over with pretty clojure
03:33	tomoj	I mean, e.g. enlive wraps over it so that a user of enlive never has to write it
04:06	LauJensen	Morning guys
04:06	bozhidar	Morning :-)
04:08	spariev	morning Lau
04:24	bartj	morning Lau
04:36	bartj	er, is it possible to call c++ from clojure (planning to call webkit functions)
04:38	LauJensen	bartj: There's a project which was/is called clojure-native (see the group), which allows you to do that
04:43	bartj	I am only able to see chouser's clojure-jna
04:43	Licenser_	mornin g
04:43	LauJensen	http://groups.google.com/group/clojure/browse_thread/thread/f0cc00d87912878b/467dc469f45498bd?lnk=gst&q=clojure+native#467dc469f45498bd
04:43	LauJensen	@ bartj
04:45	esj	Morning All
04:45	LauJensen	Morning esj
04:48	chuckler	anyone here using emacs23 and clojure-mode?
04:49	tomoj	plenty
04:51	LauJensen	chuckler: all the cool kids
04:51	LauJensen	and tomoj ...
04:51	LauJensen	:)
04:51	tomoj	:(
04:59	bozhidar	m2
04:59	bozhidar	:-)
05:40	bartj	a bit off topic - a question on sampling
05:41	bartj	A= (1 2 3 4 5), B = (1 2 3)
05:42	bartj	clearly B is a subset of A, but if I choose the wrong sampling set ie. (4, 5) then I will conclude wrongly
05:42	bartj	how do I prevent this?
05:43	bartj	ie. what is the best way to sample so that, I can check for common elements?
05:47	LauJensen	bartj: Do you just want to know if they intersect ?
05:47	tomoj	you want to guess whether B is a subset of A based on a limited number of inclusion checks?
05:48	LauJensen	$(clojure.set/intersection #{1 2 3 4 5} #{1 2 3})
05:48	sexpbot	java.lang.ClassNotFoundException: clojure.set$intersection$fn__5560
05:48	LauJensen	$(intersection #{1 2 3 4 5} #{1 2 3})
05:48	sexpbot	java.lang.Exception: Unable to resolve symbol: intersection in this context
05:48	tomoj	"B subset A" means "if it's in B, it's in A", so seems like picking random elements from B and checking whether they're in A would be the best way
05:48	LauJensen	ok, experiment in your own rpel :)
05:48	LauJensen	and swap letters where appropriate
05:49	bartj	LauJensen: actually, what elements should I pick from a given set to know that they intersect
05:50	bartj	ie. if two sets A and B intersect, and all my samples are from (A-B) then, I would conclude that they don't intersect
05:51	bartj	is there any way I can avoid this...
05:51	tomoj	suppose A and B each have 1000000 elements, and their intersection has just one element
05:51	tomoj	you're gonna have to get pretty damn lucky no matter how you sample
05:52	bartj	tomoj: yeah you are right!
05:54	bartj	tomoj: we could perhaps set a limit of 10%?
05:54	tomoj	it shouldn't be too hard to find the probability, hmm
05:55	bartj	trouble is, if all the 10,000 elements you picked are from (A-B)?
05:55	tomoj	right, but we can calculate the probability of that
05:55	tomoj	and so get some idea of how likely it is that they intersect given the evidence
05:55	tomoj	do you know the sizes of the sets?
05:56	bartj	5L and 1L
05:56	bartj	have another one which is 1M and 2L
05:57	G0SUB	LauJensen:
05:57	tomoj	what's "L" stand for?
05:57	bartj	lakh
05:57	G0SUB	what?
05:57	clojurebot	what is wrong with you
05:57	konr	Just out of curiosity: do you guys still use common lisp? If so, for what?
05:57	bartj	5L = 5,00,000
05:57	tomoj	ah, 100000?
05:57	G0SUB	bartj: are you from India?
05:58	bartj	GOSUB: yep!
05:58	bartj	I guess we use that here a lot...sorry!
05:58	tomoj	in america we are doomed to say 500K I guess
05:58	G0SUB	bartj: I am from India too.
05:58	tomoj	two extra characters :(
05:59	tomoj	I think you want to be sampling from the smaller set
06:01	bartj	tomoj: I still wouldn't want to pick all the 200,000 entries to compare against the 1M...
06:02	bartj	tomoj: that is, I do not want the sample size to be 200,000
06:02	tomoj	right
06:03	tomoj	but you will have a better chance of discovering the intersection if you sample from the smaller set
06:04	G0SUB	LauJensen: did you read my blog post on protocols?
06:07	tomoj	bartj: hmm.. the probability that you will discover the intersection with N checks depends on the size of the intersection
06:07	LauJensen	G0SUB: I did actually :)
06:07	tomoj	so it's more difficult than I thought
06:07	LauJensen	And I find your style of writing very compelling, must loot
06:07	G0SUB	LauJensen: oh, thanks, Lau. it's very valuable.
06:08	tomoj	I guess we can assume you've made N checks and haven't found any common elements
06:09	bartj	tomoj: yes you are right
06:10	bartj	tomoj: one obvious way would be to increase the size of N
06:10	bartj	tomoj: but, I want to know the upper limit of N
06:16	tomoj	well, hmm
06:23	bozhidar	G0SUB: can you post a link to this blog article?
06:23	tomoj	I don't think you can get any good handle on the probability that there is any intersection at all
06:23	G0SUB	bozhidar: http://freegeek.in/blog/2010/05/clojure-protocols-datatypes-a-sneak-peek/
06:23	tomoj	I think you may be able to get a good idea about the probability that there is an intersection of some size X
06:23	bozhidar	G0SUB: 10x
06:25	tomoj	if you sample 50% of the smaller set, I think you can be only 50% sure that there is no intersection at all
06:25	tomoj	but if you look for intersections of size X instead of any intersection you can do much better
06:28	bartj	tomoj: I am not sure I understand
06:29	tomoj	there is always the possibility that the sets share only one element
06:29	tomoj	and in that case, the problem is just to find that element
06:29	bartj	tomoj: yes
06:30	tomoj	which means if you sample 50% of the smaller set, you can only be 50% sure there is no such element
06:31	Licenser_	hmm is there any template engine in clojure that is somewhat like erb?
06:31	tomoj	:(
06:32	bartj	tomoj: yes
06:43	G0SUB	bozhidar: did you read it?
06:44	bozhidar	G0SUB: just started
06:44	G0SUB	bozhidar: oh, OK. feedback appreciated :)
06:52	bozhidar	G0SUB: great article, you've introduced a new concept in a clear and very understandable way
06:52	bozhidar	the swine flu part was very funny :-)
06:53	bozhidar	and I was surprised to find out that there is now a workaround allowing one to extend final Java classes(like String) in Clojure
06:54	G0SUB	bozhidar: thanks a lot.
06:54	LauJensen	hehe. Im glad we spent 56 billion USD on Swine Flu vaccines that nobody wanted, imagine if the whole world went around sneezing for 3 days :)
06:54	bartj	tomoj: thanks
06:54	bartj	tomoj: ...for your help
06:54	G0SUB	bozhidar: yeah, that basically solves the expression problem
06:55	patrkris	rhickey: just out of curiosity, which came first: persistent data structures or STM?
06:55	bozhidar	G0SUB: protocols support only single dispatching, right?
06:56	G0SUB	bozhidar: right. for arbit dispatch, you need multimethods
06:56	patrkris	rhickey: in Clojure, that is
06:56	G0SUB	bozhidar: in case you need only type/class based dispatch, use protocols :)
06:56	rhickey	patrkris: persistent data structures. Without them, I don't think STM works
06:57	bozhidar	G0SUB: I imagine so, it's just that in the beginning multimethods are always marketed as vastly superior to single dispatch based on the type
06:57	rhickey	patrkris: but thinking about how STM might work added to the desire for pds as the default
06:58	bozhidar	and later we see such a feature introduced :-)
06:58	G0SUB	bozhidar: superior, but slow :)
06:58	patrkris	rhickey: ah... but when you initially started developing Clojure, did you know that you wanted to have STM in it?
06:59	patrkris	rhickey: I am just wondering whether it is correct to say that Clojure was designed from the beginning to include STM.
06:59	rhickey	patrkris: I knew I wanted another model for state
07:00	rhickey	patrkris: It's not necessary like there was a clear point of "I'm going to write a language and this is what will be in it". More like a lot of ideas swirling around, among which was adding direct perception to the Actor model, which also pointed to pds and some sort of reference types
07:01	rhickey	what I knew was, I wanted 'doing the right thing' with state to be automatic and enforced, without adopting a static type system
07:02	rhickey	eventually there was enough alignment between all the ideas to make Clojure inevitable
07:02	patrkris	rhickey: Interesting. Another thing out of curiosity: When did you write the first line of code for what was to become Clojure? :)
07:05	rhickey	patrkris: sometime in 2005
07:06	rhickey	sourceforge project started in May 2005, so at that point I knew I was doing a language, and its name
07:06	SinDoc	I evaluate [1] and get: java.lang.ClassCastException: java.lang.Boolean cannot be cast to clojure.lang.Symbol (pair.clj:1) Any ideas?
07:06	SinDoc	[1] http://github.com/sindoc/algorithms/blob/master/src/clojure/main/com/khakbaz/algorithms/clojure/memory/fixed/manual/pair.clj
07:06	G0SUB	rhickey: would you mind if we create your action figure? It would be a very cool addition to our office desks.
07:07	Licenser_	SinDoc: it is in a require
07:07	patrkris	rhickey: Thanks for taking your time to answer my questions. :)
07:09	SinDoc	Licenser_: I'm not sure what's wrong with that!
07:15	G0SUB	SinDoc: (:require [com.khakbaz.algorithms.clojure.memory.fixed.pair :as p])
07:17	Licenser_	SinDoc: one of the files you require is wrong
07:17	G0SUB	SinDoc: you missed the manual part
07:18	G0SUB	SinDoc: I was wrong. sorry.
07:18	SinDoc	G0SUB: Licenser_: There are actually two pair.clj files
07:18	G0SUB	SinDoc: saw. sorry
07:18	SinDoc	Thanks G0SUB what you said, worked
07:19	G0SUB	SinDoc: yeah, the syntax was wrong. your ns name was correct :)
07:20	rhickey	urk - why are there clojure jars in clojars?
07:20	rhickey	when there is build.clojure.org
07:21	Licenser_	rhickey: I think clojars subdirectories clojars
07:21	rhickey	and is there a way to force maven to get clojure and contrib jars only from build.clojure.org?
07:21	Licenser_	but I'm not sure if that is what you mean
07:25	SinDoc	Thank you folks! See you soon ;)
07:32	G0SUB	rhickey: a lot of people are asking how protocols are different from haskell's type classes and Go's interfaces. what is the right answer to this question?
07:32	rhickey	G0SUB: sounds like 2 questions to me
07:33	G0SUB	rhickey: I grouped them together for brevity.
07:33	G0SUB	rhickey: you can give me two answers :)
07:36	rhickey	they differ from Haskell's type classes (from which they draw partial inspiration) in that the dispatch map isn't an independent entity passed around by the type system, and thus can't do return-type based method selection, and generally in that they are not static-type-system-based.
07:37	G0SUB	rhickey: thanks!
07:38	rhickey	they differ from Go interfaces in that Go just uses method conformance to determine interface support (vs explicit declaration of 'I implement this protocol'), and Go's interfaces, last time I checked, were only 'open' within a module.
07:38	G0SUB	ah
07:39	rhickey	If one said Clojure's protocols were like dynamic type classes you wouldn't offend me (but might offend some Haskellers)
07:39	G0SUB	heh
07:39	rhickey	but they are not very much like Go interfaces at all
07:41	G0SUB	whenever Blub programmers look at protocols, they say it's identical to the Transmogrify feature in Blub.
07:42	rhickey	G0SUB: the differences can be subtle, but are important
07:43	G0SUB	rhickey: indeed.
07:43	G0SUB	It's like saying Agents are identical to Actors
07:43	cemerick	rhickey: maven will grab dependencies from whereever it can get them, I believe. Stricter controls require the use of a proxy (e.g. nexus).
07:43	cemerick	clojars is a bit of a swamp w.r.t. following maven conventions
07:44	rhickey	cemerick: then I'm concerned about people putting their own Clojure jars in clojars
07:44	cemerick	rhickey: yeah, it simply shouldn't happen
07:44	cemerick	same goes for sha version numbers, misuse of classifiers, etc etc
07:46	cemerick	I'm guessing most people don't know that they're using a maven repo, and so without indications to do otherwise, they do what seems to make sense at the time, etc.
07:46	AWizzArd	cemerick: what do you mean by thas "sha version numbers" thing? Is it that some people try to depend on a specific version via hash, and that is not good?
07:46	rhickey	but something must have driven people to use clojars for Clojure vs build.clojure.org
07:47	cemerick	AWizzArd: I mean artifacts published with a sha1 version number instead of something like 1.5.9 or whatever.
07:47	AWizzArd	Oh okay, yes.
07:47	cemerick	rhickey: I presume just not knowing what should be done. Probably best to ping whoever pushed the libs to see what's up.
07:48	cemerick	bleh, no authorship notation in the accompanying poms
07:49	cemerick	rhickey: I'd say ato should just rm org/clojure/*, and make that dir read-only.
07:50	cemerick	anyone can push stuff up into clojars, which is good and bad
07:50	cemerick	eh, ok, so it's probably just all bad :-)
07:52	bozhidar	cemerick: giving anyone access to something always ends bad :-)
07:53	cemerick	rhickey: if there's to be any infrastructure managed by clojure/core, dropping a nexus instance on it as well would be a wise thing, I think. That'd presumably require some coordination with technomancy\|away, insofar as lein pushes at clojars by default (or, exclusively?).
07:54	cemerick	bozhidar: it's fine as long as you can see who did what when :-)
07:54	rhickey	cemerick: is nexus free for open source?
07:54	cemerick	rhickey: and for closed source as well :-)
07:54	cemerick	nexus pro costs, but the free version is extraordinarily full-featured.
07:55	cemerick	proxying, access control, host as many repos as you want, repo aggregation, etc.
07:57	cemerick	Looks like LDAP and P2 itnegration are the big additions in Pro http://nexus.sonatype.org/
07:57	cemerick	integration*
07:59	cemerick	rhickey: have you been following the java closure goings-on much?
08:00	rhickey	cemerick: not too much, I like #() though :)
08:00	cemerick	heh, yeah
08:01	cemerick	I saw this as a "function type", and almost fell over though: #int(int, int)(throws IOException \| SQLException) plusClosure = #(int
08:01	cemerick	a, int b) (a+b);
08:02	rhickey	checked exceptions showing their inherent evil again, will be the downfall of Java closures
08:02	cemerick	I can't imagine anyone's going to use that stuff.
08:02	cemerick	it seems like Oracle would be doing everyone a favor if they just got the non-Java language principals in the room, and did what they wanted (forgetting Java)
08:04	rhickey	getting rid of checked exceptions and adding a smattering of inference would go a long way, neither in the cards afaik
08:04	G0SUB	lol
08:06	rhickey	I'd be happiest if Java would just stay as-is, BUT, there is one very important side-effect of getting closures in to Java, which is: then (and only then?) they may start looking at the optimizations needed for higher-order functions like map et al
08:07	cemerick	gah, we'll probably have to type-hint our fns! :-x
08:07	cemerick	Seems like there's a lot of interop pain coming down the pike.
08:07	rhickey	cemerick: nope - Object, Object, Object...
08:08	bobo_	cemerick: that example is just the absolute worst scenario though, for everyday use it wont be THAT ugly, still ugly though
08:08	rhickey	cemerick: yes, interop the problem for alternate langs. Wanna bet the reflection story for these will stink?
08:08	cemerick	rhickey: but if Java libs start requiring function params of type #int(int, int)?
08:08	cemerick	oh, right, erasure
08:09	cemerick	though I saw someone on the mlvm list talking about "fixing" erasure not too long ago
08:09	rhickey	cemerick: depends
08:09	rhickey	cemerick: erasure is the best thing ever
08:10	cemerick	yeah; I caught a glimpse of what D. Miller is having to deal with with ClojureCLR, and felt bad for him.
08:11	rhickey	cemerick: yes, people don't realize the huge tradeoff involved in the CLR approach. It greatly complicates life for everyone, and is a poor fit for dynamic langs
08:12	G0SUB	by erasure, do we mean type erasure here?
08:12	cemerick	yeah
08:12	cemerick	rhickey: I presume the DLR doesn't just make it all go away magically?
08:12	rhickey	cemerick: nope
08:14	bozhidar	rhickey: can we expect some dramatic performance improvements on JDK 7 because of http://java.sun.com/developer/technicalArticles/DynTypeLang/
08:15	bozhidar	I read somewhere that to reap the benefits one has to rewrite a lot of him current implementation however
08:16	bozhidar	his*
08:17	rhickey	bozhidar: no, most of what you can do with invokedynamic you can do without it, it's just a bit cumbersome. But we've all done it already
08:18	rhickey	and few langs will want to be Java-7 only
08:19	bozhidar	rhickey: I've read some article from Charles Nutter from JRuby in which he claimed this invoke dynamic will be the holy grail of dynamic languages targeting the JVM
08:19	rhickey	It would have been better if they had just made classes themselves cheaper and faster
08:20	bozhidar	he mentioned that JRuby's performance will increase 10 fold, so I was wondering is Clojure affected in a similar manner
08:20	bozhidar	probably an implementation detail?
08:20	rhickey	bozhidar: is he still saying that today?
08:20	bozhidar	rhickey: let me look up some articles
08:21	bobo_	i think that mainly is because of heavy Reflectionusage they can remove
08:21	rhickey	method handles are just going to be an entirely new thing hotspot et al are going to have to be taught to optimize. They are already awesome at optimizing ordinary class method dispatch
08:22	rhickey	bobo_: invokedynamic is not needed for removing reflaction
08:22	rhickey	reflection
08:22	bobo_	no, but i think that is what nutter was saying.
08:22	bobo_	that jruby has loads of reflection, and they might remove that with invokedynamic
08:22	rhickey	it is just a different way of doing call site caches, which you can already do today with classes and methods
08:23	bobo_	was long ago i read the article though.
08:23	bozhidar	rhickey: the only article I find is a bit old - http://blog.headius.com/2008/09/first-taste-of-invokedynamic.html
08:23	rhickey	but, you end up with a lot of classes, so, IMO, make that cheaper
08:23	bozhidar	maybe he has reconsidered indeed :-)
09:12	SinDoc	I evaluate a .clj file and would like to interact with it using REPL. How can I have REPL automatically switch to a namespace other than the user ns?
09:13	SinDoc	I use IntelliJ and LaClojure
09:35	bartj	is there a better way to filter nils then do - (filter (complement nil?) [nil 1 2 nil nil])
09:35	bartj	,(filter (complement nil?) [nil 1 2 nil nil])
09:35	clojurebot	(1 2)
09:36	pjstadig	,(remove nil? [nil 1 2 nil nil])
09:36	clojurebot	(1 2)
09:40	bartj	pjstadig: thanks
09:40	cgrand	SinDoc: (in-ns 'foo)
09:40	pjstadig	np
09:42	G0SUB	bartj: if you see yourself using double negative verbs, know that there must be a positive verb too :)
09:42	SinDoc	cgrand: I've been trying that BUT without the quote
09:43	bartj	G0SUB: thanks!
09:43	G0SUB	bartj: np :)
09:46	SinDoc	cgrand: I put (in-ns 'myns) in code but after evaluation, it's still in the user namespace
09:47	cgrand	SinDoc: enter it at the repl
09:47	SinDoc	That's kinda the reason why I asked
09:48	SinDoc	I was hoping to make that implicit somewhere
09:48	cgrand	how do you eval your file?
09:49	SinDoc	I create a Run configuration for it in IntelliJ and simpley 'Run' it.
09:49	SinDoc	Then it evaluates my definitions but goes back to the user ns
09:54	cgrand	ok, too LaClojure specific for me then, sorry
09:54	SinDoc	Thanks cgrand
09:57	bozhidar	is there some existing way to take items in frame fashion from a sequence
09:57	bozhidar	for example I have 1 2 3 4 5
09:57	bozhidar	first I take 1 2 3
09:57	bozhidar	then 2 3 4
09:57	bozhidar	3 4 5
09:58	bozhidar	the frame being x items wide and advancing by one each time
09:59	vu3rdd	,(partition 3 1 [1 2 3 4 5 6])
09:59	clojurebot	((1 2 3) (2 3 4) (3 4 5) (4 5 6))
09:59	Joreji	Hey guys, I'd like to set a clojure variable from java code, is it possible to do it like this: String path = "/data/clojure/classes"; Var.pushThreadBindings(RT.map(Compiler.COMPILE_PATH, path));
10:00	vu3rdd	bozhidar: is that what you want?
10:00	bozhidar	vu3rdd: perfect, totally forgot about partition
10:01	bozhidar	vu3rdd: thanks
10:01	vu3rdd	bozhidar: no problem.
10:01	G0SUB	vu3rdd
10:01	vu3rdd	G0SUB: hi
10:02	G0SUB	bozhidar: also, don't forget partition-all :)
10:02	G0SUB	vu3rdd: how are you?
10:02	vu3rdd	G0SUB: fine. Was sick for the past 3-4 days. Back to work today
10:02	G0SUB	vu3rdd: Can I PM you?
10:02	vu3rdd	G0SUB: sure
10:03	bozhidar	G0SUB: never new about partition-all, what is its deal?
10:04	spariev	,(partition 3 [1 2 3 4])
10:04	clojurebot	((1 2 3))
10:04	spariev	,(partition-all 3 [1 2 3 4])
10:04	clojurebot	((1 2 3) (4))
10:04	hoeck	Joreji: not shure, but I believe pushThreadBindings is the same as of binding in clojure, so it shares its limitations
10:04	G0SUB	spariev: bravo!
10:04	bartj	, (partition 3 2 [1 2 3 4 5 6 7])
10:04	clojurebot	((1 2 3) (3 4 5) (5 6 7))
10:05	bartj	step=2 and still the same results?
10:05	G0SUB	,(partition 3 2 [1 2 3 4 5 6 7 8])
10:05	clojurebot	((1 2 3) (3 4 5) (5 6 7))
10:05	spariev	G0SUB: this difference struck me badly last week )
10:05	hoeck	Joreji: Var.alterRoot(...) alters the root binding, which is a bit more like "setting" the var
10:06	hoeck	Joreji: though I've never interfaced clojure from java, only the other way around :P
10:07	G0SUB	,(partition 3 2 [1 2 3 4 5 6])
10:07	clojurebot	((1 2 3) (3 4 5))
10:07	G0SUB	bozhidar: ^^^
10:07	Joreji	hoeck: Thanks, I'll try that out!
10:08	G0SUB	,(partition-all 3 2 [1 2 3 4 5 6])
10:08	clojurebot	((1 2 3) (3 4 5) (5 6))
10:08	G0SUB	bozhidar: ^^^
10:08	bozhidar	I see
10:09	bozhidar	G0SUB: 10x
10:10	G0SUB	bozhidar: np
10:11	bartj	,(doc partition)
10:11	clojurebot	"([n coll] [n step coll] [n step pad coll]); Returns a lazy sequence of lists of n items each, at offsets step apart. If step is not supplied, defaults to n, i.e. the partitions do not overlap. If a pad collection is supplied, use its elements as necessary to complete last partition upto n items. In case there are not enough padding elements, return a partition with less than n items."
10:12	bartj	what does "offsets step apart" mean?
10:14	cgrand	rhickey: any chance that #353 and #362 are related?
10:29	hugod	cgrand: thanks for finding the cause of #368. I have also been having issues with redefining multimethod dispatch functions which I assume is related. Makes interactive development very frustrating :(
10:31	cemerick	hugod: that's a known issue at the moment, noted in #309
10:31	hugod	cemerick: thanks, hadn't spotted that one
10:33	cemerick	seems like #368 should be moved into 1.2, no?
10:34	cgrand	who decieds what's in &
10:34	cgrand	1.2
10:35	pedroteixeira	one would create a new Exception type using deftype or using someting else? is there any macro for this already?
10:36	cemerick	cgrand: Stu's the only one outside of Rich that I know of who's got carte blache to promote issue.
10:36	cemerick	issues*
10:37	cemerick	anyone can do it, of course, but that's not so polite :-)
10:37	cemerick	pedroteixeira: why are you wanting to create a new Exception type?
10:38	pedroteixeira	cemerick: sometimes it's useful, isn't? instead of returning error codes for ex. Just tested and this worked fine: (deftype DomainException [Exception]) (DomainException. "oops")
10:39	cgrand	cemerick: ok, we have the same policy
10:40	cemerick	pedroteixeira: It's pretty rare for new exception types to be useful IMO. It's not really idiomatic within Clojure, certainly.
10:40	pedroteixeira	cemerick: i'm builind a large application, some part of the code might throw exceptions that have known semantic and can be handled specificly in a different part of the code.
10:41	pedroteixeira	cemeric: ok, thanks. will think about it.
10:42	Raynes	http://groups.google.com/group/clojure/browse_thread/thread/ad7f33cc59ce13cb?pli=1 This guy is officially awesome.
10:42	cemerick	pedroteixeira: if there's actually a recovery path available, then I'd consider it. Most applications don't have a reasonable recovery path though.
10:43	cemerick	Otherwise, IllegalArgument, IllegalState, IOException, etc. are good for 95% of the "oh, shite" error conditions that are likely to arise.
10:43	nDuff	What's the appropriate concurrency device to use for hashing a large tree of files? Agents, promises and futures all look potentially interesting.
10:43	pedroteixeira	cemerick: my current case is to handle possible ConflictException that has an entity with version. Different use cases, might retry and some might just return an error to the user.
10:44	pedroteixeira	cemerick: alright, i'm aware of those also ;)
10:46	hugod	pedroteixeira: you might also want to look at clojure.contrib.condition
10:47	pedroteixeira	hudod: thanks! looks useful
10:54	islon	how can I access an inner java class in clojure? I want to use javax.mail.Message.RecipientType
10:54	spariev	javax.mail.Message$RecipientType , IIRC
10:55	pedroteixeira	hudod: i think clojure.contrib.condition suits my needs fine.. one generic exception to rule them all :)
10:55	islon	thanks =)
11:17	jfields	can you memoize method calls on an instance of a java object?
11:19	cgrand	jfields: you have to wrap the method call in a fn: (memoize #(.substring s %))
11:19	pedroteixeira	jfields: memoize operates on pure functions, you can probably more easily just wrap this java call to a particular object..
11:20	jfields	cgrand, pedroteixeira: cool, thanks.
11:22	cgrand	hugod: http://github.com/richhickey/clojure/commit/f47b3d6f028e0370c495383731a449092d0ae451 fixes #368 too
11:22	pedroteixeira	jfields: sometimes, you don't want memoization for the entire lifecycle of your app (i.e. for memory constraints), then you can just bind the memoized function (the return of memoize) to a local scope.
11:38	hugod	cgrand: excellent :)
11:43	pedroteixeira	are there any recommended way to serialize clojure records? (with-in-str (binding [print-dup true] (pr-str (Foo. "bar"))) (read)) gives an exception.
11:43	_fogus_	dnolen: ping
11:43	dnolen	_fogus_: pong
11:43	_fogus_	dnolen: Do you mind if I use clj-cont in a presentation?
11:44	dnolen	_fogus_: not at all, I saw that you forked it.
11:44	dnolen	_fogus_: what is the presentation going to be about?
11:45	_fogus_	dnolen: Thanks! Delimited continuations (probably)
11:48	hiredman	ping?
11:48	clojurebot	PONG!
11:48	_fogus_	dnolen: I was going to use Scala for the preso, but thought better of it
11:49	dnolen	_fogus_: interesting, do you find the ideas easier to express in Clojure?
11:51	_fogus_	dnolen: I hadn't thought about it that way, but I would probably say yes.
11:57	LauJensen	_fogus_: glad you sobered up
11:59	Raynes	LauJensen: He puffed the magic dragon too many times last night.
12:01	LauJensen	_fogus_: You shouldn't focus on Scala daily, spend a little more time with Clojure before you finish the book please :)
12:13	_fogus_	LauJensen: What?! You don't like the latest chapter "Typed Clojure" ? :p
12:13	LauJensen	haha
12:21	dnolen	_fogus_: so where do you feel that Scala's type system comes in handy when writing real programs? I've been wondering whether good type systems still make certain kinds of real world programming more tedious.
12:24	_fogus_	dnolen: Scala's type system has benefited me in a couple of ways. 1) We have a fairly static system that we spent many moons agonizing over the design and Scala's types served as (sort-of) documentation. and 2) Because our types are rock solid, I've found that if it compiles then it's correct.
12:25	_fogus_	However, I wouldn't want to do that same exercise (agonizing design) on every project
12:31	cemerick	_fogus_: I didn't agonize enough on my first scala project -- so when things had to change in some tiny way, I was faced with a boil-the-ocean refactoring. Not fun at all.
12:32	_fogus_	cemerick: That was definitely a problem at first, but I (erm.. we) buckled down and solidified the API.
12:32	cemerick	Right. More work always makes problems go away. ;-)
12:33	_fogus_	cemerick: I like to think I didn't work harder but.... uhhhh... well not smarter either. :p
12:33	cemerick	I generally assume I'm going to bork my first four shots at something, and it's oh-so-nice to just add a slot to a map that gets passed around everywhere instead of having to shatter my carefully-crafted domaint types.
12:34	_fogus_	cemerick: The borked part was the previous system.
12:41	naeu	hi there
12:42	naeu	I'm currently playing around with type hints trying to remove use of reflection for the core pathways of my system
12:42	naeu	however, I'm not having much luck in a particular case: (.write out-stream bytes)
12:43	naeu	I tried: (.write #^java.io.OutputStream out-stream bytes)
12:43	naeu	but the reflection warning still flags that line
12:43	naeu	(call to write can't be resolved.)
12:45	cemerick	naeu: there are both int and byte[] overloads for .write
12:45	naeu	cemerick: oh ok, so how would I find that out?
12:45	naeu	do i need to inspect the javadoc, or is there a way i can ask clojure for this information?
12:45	cemerick	hrm; be familiar with the signatures of the methods you're calling, or have javadoc ready :-)
12:46	naeu	also, how would i type-hint byte[]
12:46	cemerick	it would be nice if the reflection warnings could point at whether the invocation target's type is unknown, or if it's trying to choose from a number of known overloads
12:46	cemerick	naeu: #^bytes should do it if you're using a pre-1.2 build
12:47	cemerick	otherwise, it's ^bytes
12:47	naeu	cemerick: haha, I keep reading overlords instead of overloads
12:47	naeu	I like the idea of choosing from a number of known overlords
13:18	KirinDave	cemerick: pingggggg
13:19	DeusExPikachu	if I want to generate a fn that's code depends on runtime information, must I use eval?
13:19	KirinDave	If you want to let outside input build code, that is what eval does.
13:20	KirinDave	But it's very rare that it's necessary.
13:23	DeusExPikachu	so to be more precise, I want a `(fn [] ~@(for [f# my-runtime-vector-of-fns] (f#)), I'm thinking I can't use defmacro for this cause at compile time my-runtime-vector-of-fns is not defined
13:27	DeusExPikachu	hmm, I think that code is wrong too, cause f# needs to be symbols not fns...
13:28	ericthorsen	cemerick: you still having frequent NB crashing?
13:28	ericthorsen	wroiong window
13:46	bsteuber	is it documented somewhere that it's not a clever idea to call a record field "size"?
13:47	bsteuber	say (defrecord Foo [size]) (:size (Foo. 42)) -> 1
13:56	cemerick	bsteuber: that's a bug from a few weeks ago that was fixed. Try a newer snapshot?
13:57	LauJensen	cemerick: is it just me, or does it seem that there is an increase in bugs recently ?
13:58	bsteuber	cemerick: ah, I froze my clojure version for swank
13:59	cemerick	LauJensen: Not sure you could characterize it as that. Part of it is stuff new in 1.2 being shaken out, which is going to produce some regressions.
13:59	LauJensen	Sounds like you expected that?
14:00	cemerick	it's inevitable as things draw up to a release, no?
14:00	cemerick	I'd be more concerned if issues weren't being raised -- that'd indicate a lack of thorough testing.
14:00	LauJensen	Relative to your workflow I presume
14:00	kotarak	LauJensen: I got the impression that 1.2 broke way more often than the versions before. The only things similar annoying was the initial use/require move.
14:00	LauJensen	That matches my experience kotarak
14:01	kotarak	cemerick: and (sometimes trivial) things won't get fixed... At least not contemporary...
14:01	LauJensen	contemporary ?
14:01	cemerick	I think he means lately.
14:02	LauJensen	Aha
14:03	kotarak	Ok. Dictionary issue. contemporary <=> zeitnah, meaning close in time. Things are reported now and fixed two months later <=> not contemporary. :/
14:03	cemerick	ah, timeliness
14:04	LauJensen	Ok - Also sometimes the magnitude of the bugs surprises me, like the effect of removing numbering in fns for instance
14:04	cemerick	The best I can suggest is to make noise about it, here and on the dev list.
14:05	LauJensen	Yes that would be the next move - Just wanted to be sure I wasn't the only one feeling it
14:05	stuarthalloway	late to the conversation ... feeling what?
14:05	kotarak	Well. This is nothing new. I hope things approve with the new leutnants.
14:06	stuarthalloway	what did removing numbering cause?
14:06	LauJensen	stuarthalloway: feeling an increase in bugs, both frequency and magnitude
14:06	kotarak	stuarthalloway: that it takes sometimes quite long to fix things. (even with patch available)
14:06	LauJensen	stuarthalloway: Caused toplevel macros to be un-redefinable, see hugods bugreport
14:06	stuarthalloway	ok, will discuss with Righ
14:07	stuarthalloway	(Rich)
14:07	LauJensen	Ok
14:08	cemerick	Even if that were true, I'm not sure what the "solution" would be.
14:08	cemerick	"Don't cause bugs"? ;-)
14:08	LauJensen	cemerick: right, I was just poking to verify and maybe guess the cause, change in workflow, whatever
14:09	cemerick	well, many fundamental things have changed over the last months, so I'd expect that.
14:10	cemerick	kotarak's issue with the cadence of patches being applied is a separate issue though; the same thing applies in contrib as well, which Chousuke raised as an issue on the dev list a while back.
14:11	kotarak	cemerick: I kind of complained also. is stuarthalloway now kind of leutnant to Rich? That would help things, I think. (I know, that Rich has a lot to do. A leutnant team would allow him to focus...)
14:15	cemerick	kotarak: I presume that's what clojure/core is meant to accomlish.
14:15	kotarak	cemerick: yeah thumbsup
14:15	cgrand	stuarthalloway & LauJensen, http://github.com/richhickey/clojure/commit/f47b3d6f028e0370c495383731a449092d0ae451 fixed #368 too
14:17	LauJensen	Yea i noticed
14:24	bsteuber	is there a function converting a lazy seq into another lazy seq with all duplicates removed?
14:26	bsteuber	nevermind - I should use find-doc more often :)
14:26	kotarak	oeh? Does someone have trouble with current git?
14:26	kotarak	I get a NPE in a macroexpansion in protocols.clj line 11 (a defprotocol)
14:27	LauJensen	kotarak: when compiling, using, what?
14:27	kotarak	compiling with ant
14:27	LauJensen	k, sec
14:28	kotarak	Does it need mvn now?
14:28	LauJensen	Rich hates mvn :)
14:28	kotarak	(Man! I'm disconnected with the 1.2 at the moment.... :/ )
14:29	LauJensen	kotarak: core.protocols compiles fine here
14:29	kotarak	what changeset?
14:29	LauJensen	changeset? I just cloned HEAD
14:30	kotarak	Hmm... Me too.
14:30	LauJensen	build.clojure.org gives the green light as well
14:30	kotarak	geez
14:31	kotarak	Caused by: java.lang.NullPointerException (protocols.clj:11)
14:32	LauJensen	kotarak: Could it be caused by the fact that you've renamed all the functions in core to have german names ?
14:32	kotarak	LauJensen: hehe. Unlikely.
14:32	cemerick	kotarak: sounds like you just need a clean build?
14:32	kotarak	cemerick: I did a fresh checkout. ant clean. ant.
14:33	kotarak	will iterate
14:33	cemerick	kotarak: what's the sha you have?
14:33	kotarak	f47b3d6f028e
14:35	kotarak	Hmpf.
14:35	kotarak	Works now.
14:36	cemerick	good here
14:36	cemerick	heh
14:36	kotarak	cemerick: I hate such errors. :(
14:36	cemerick	kotarak: it's those neutrinos hitting the DRAM :-)
14:36	kotarak	cemerick: dawn butterflies. ;)
14:37	kotarak	damn
14:37	cemerick	kotarak: just not your day, huh?
14:37	kotarak	cemerick: seems so.
14:37	cemerick	kotarak: are you still an hg loyalist?
14:38	kotarak	cemerick: yup
14:38	LauJensen	Oh yes he is :)
14:38	LauJensen	And I've got the "git sucks" inbox to prove it
14:38	kotarak	geninterface methods might also be strings, right?
14:38	cemerick	kotarak is the only hg evangelist I've had much of any contact with, so I wonder from time to time. :-)
14:39	kotarak	cemerick: I just like it more than git. So much easier to use.
14:39	cemerick	stuarthalloway: I love the change to name, FWIW. Thankyouohthankyou. :-)
14:39	cemerick	kotarak: I like my SCM as cryptic as possible. Keeps out the riff-raff. ;-)
14:41	LauJensen	cemerick: change to name?
14:41	kotarak	cemerick: yeah. git is probably pretty cool. I just don't use it often enough to hardwire things in my spine. I can return to hg after work with git and everything works immediately. The other way around? No way.
14:41	kotarak	nDuff: well. nothing new. The usual "git's interface sucks" argument. But I use both, prefering hg. I'm not even sure, that svn is the enemy.
14:42	cemerick	kotarak: that ;-) should've been in bold. I'm actually a tech populist, and would rather have hg's UX but git's guts. But I'm also pragmatic.
14:42	stuarthalloway	hey all, was on the phone a few minutes, would love to go back and respond to several things
14:42	cemerick	LauJensen: Second System
14:42	cemerick	bah
14:42	cemerick	LauJensen: http://github.com/richhickey/clojure/commit/4bea7a529bb14b99d48758cfaf0d71af0997f0ff
14:43	LauJensen	k :)
14:43	stuarthalloway	cemerick: rich is reviewing the thread on the dev list re: #352 (macro clearing meta). there may be subtleties there so I wasn't going to answer without his input
14:43	nDuff	kotarak, I remember Arch's interface enough that while I think git takes the wrong approach in asking users to learn to think in its terms, it's not exactly unprecedented. :)
14:44	cemerick	stuarthalloway: I didn't have any questions on #352?
14:44	stuarthalloway	doh! sorry, that was cgrand
14:45	stuarthalloway	too much multitasking
14:45	LauJensen	relax stuarthalloway, you are among friends :)
14:45	stuarthalloway	LauJensen: I have been working to add tests for both new code and for regressions as they are fixed
14:45	LauJensen	Great, thanks alot on behalf of the community
14:46	stuarthalloway	but that doesn't necessarily prevent some short-term pain
14:46	LauJensen	of course
14:47	stuarthalloway	also, I think that tickets have been moving through more quickly than in the past. Perception is often a lagging metric for such things
14:48	stuarthalloway	kotarak: the NPE at line 11 in protocols could be caused by reloading the code for a protocol, if that protocol called itself during the reload while things were in a half-baked state
14:49	stuarthalloway	when that has been a problem in the past it is a heisenbug -- very irritating to track
14:49	kotarak	stuarthalloway: I think I understand what happens. I'm trying to address the - in interface method names issue.
14:49	stuarthalloway	interface or protocol? interfaces can't have - in their names
14:50	kotarak	stuarthalloway: (when (some #(-> % first name (.contains "-")) methods) (throw ...)) in generate-interface causes the NPE.
14:50	cgrand	stuarthalloway: great to know (#352)
14:50	kotarak	stuarthalloway: right. the thread from the list, you said, gen-interface/definterface should error out.
14:50	kotarak	stuarthalloway: working on a patch
14:50	stuarthalloway	kotarak: cool
14:51	kotarak	stuarthalloway: obviously defprotocol somehow calls into gen-interfae
15:01	kotarak	oeh. I'm in trouble with name.
15:02	kotarak	I insert internal_reduce. A symbol. But name returns nil.
15:06	Borkdude	how do I maximize a list of things based on their content?
15:07	Borkdude	like this: [[1 2] [1 3]] => [1 3]
15:07	Borkdude	list comprehension with for?
15:08	kotarak	Borkdude: max-key?
15:08	kotarak	(doc max-key)
15:08	clojurebot	"([k x] [k x y] [k x y & more]); Returns the x for which (k x), a number, is greatest."
15:08	Borkdude	great
15:08	kotarak	,(apply max-key second [[1 2] [1 3]])
15:08	clojurebot	[1 3]
15:09	Borkdude	kotarak: what a relief this exists :)
15:10	kotarak	locals named after core functions. In particular "name". Pfff
15:13	tgk	What is the idiomatic way to return false for an expression when it evaluates to nil?
15:13	kotarak	tgk: return nil
15:14	tgk	What if it is used in a function with a foo? name? Idiomatically I wouldn't want foo? to return nil.
15:15	tgk	I could use (not (nil? ...)), but is there a nicer way?
15:16	LauJensen	hehe, "what is the idiomatic way to return false?" "return nil" - are you kidding kotarak ? :)
15:16	kotarak	,(boolean nil)
15:16	clojurebot	false
15:16	kotarak	tgk: see above
15:16	tgk	Oh, cool. Thanks.
15:19	kotarak	What a look there are languages with type inference.
15:19	kotarak	luck
15:21	_fogus_	kotarak: Hey, it is able to infer the return type on the RHS :p
15:22	kotarak	Wow. I'm impressed. ;) What's that? Scala?
15:23	_fogus_	kotarak: Java7
15:23	kotarak	o.O
15:41	bartj	,(find-doc "lazy-cons")
15:41	clojurebot	nil
15:42	bartj	er, is "lazy-cons" a function - if yes there isn't any documentation? - http://en.wikibooks.org/wiki/Clojure_Programming/Examples/Lazy_Fibonacci
15:42	hiredman	lazy-cons hasn't existed since before 1.0 was released
15:42	hiredman	sexpbot: leave me alone
15:43	kotarak	bartj: It's now named lazy-seq. See http://clojure.org/lazy
15:44	bartj	kotarak: thanks!
15:44	hiredman	lazy-seq is not lazy-cons with a new name
15:45	kotarak	hiredman: I know.
15:45	_fogus_	,(doc cons)
15:45	clojurebot	"([x seq]); Returns a new seq where x is the first element and seq is the rest."
15:47	_fogus_	with a combination of what kotarak said
16:00	timcharper	I'm wanting to do this: write a function that receives a writer and a list of headers, and then returns a function that receives a hash map and writes the data to the writer
16:01	timcharper	It needs to be able to be called by multiple threads in parallel, so it should process writes serially
16:01	timcharper	I'm thinking that agents are the best tool to use for this.
16:01	timcharper	Am I wrong to reach for this?
16:03	neotyk	bartj: this example caused quite some confusion in my head as well, should be updated
16:04	bartj	neotyk: I thought I was the only one with a head-ache now
16:04	bartj	neotyk: any simple examples on lazy-seq?
16:05	timcharper	.... agents it is then
16:06	neotyk	bartj: not really, let me think
16:08	tomoj	timcharper: but if you send off to the agent multiple times, the IO won't happen serially, will it?
16:09	neotyk	,(doc lazy-seq)
16:09	clojurebot	"([& body]); Takes a body of expressions that returns an ISeq or nil, and yields a Seqable object that will invoke the body only the first time seq is called, and will cache the result and return it on all subsequent seq calls."
16:11	neotyk	,(take 10 (lazy-seq (cycle [1 2 3])))
16:11	clojurebot	(1 2 3 1 2 3 1 2 3 1)
16:11	neotyk	bartj: though it doesn't make sense, as
16:11	tomoj	,(take 10 (cycle [1 2 3]))
16:11	clojurebot	(1 2 3 1 2 3 1 2 3 1)
16:11	neotyk	,(take 10 (ccyle [1 2 3]))
16:11	clojurebot	java.lang.Exception: Unable to resolve symbol: ccyle in this context
16:11	neotyk	as exactly tomoj says
16:12	bartj	since cycle itself is lazy, why are we passing it through lazy-seq again?
16:12	tomoj	no good reason
16:12	neotyk	so whats use of lazy-seq?
16:13	tomoj	cycle already returns a lazy seq
16:13	kotarak	bartj: (lazy-seq (cons (do (println "huhu") :first) nil))
16:13	tomoj	not everything returns a lazy seq
16:13	neotyk	bartj: was trying to come up with some body that will generate seq
16:13	kotarak	bartj: try in the repl, first (def x (lazy-seq ...) Then (first x)
16:14	tomoj	,(take 10 ((fn fib [i j] (lazy-seq (cons i (fib j (+ i j))))) 1 1))
16:14	clojurebot	(1 1 2 3 5 8 13 21 34 55)
16:14	bartj	an example which doesn't involve recursion would be good
16:15	tomoj	I don't think I've ever used lazy-seq without recursion
16:15	kotarak	bartj: see my example above
16:15	kotarak	bartj: it shows the effect of lazy-seq
16:17	bartj	er, it looks like a seq was not created at all?
16:18	neotyk	(let [x (lazy-seq (conj '() (do (println "ein") 1) (do (println "twei") 2)))] (first x))
16:18	neotyk	,(let [x (lazy-seq (conj '() (do (println "ein") 1) (do (println "twei") 2)))] (first x))
16:18	clojurebot	2
16:18	clojurebot	ein twei
16:19	kotarak	neotyk: you have to nest the lazy-seqs
16:20	neotyk	,(let [x (lazy-seq (cons (do (println "ein") 1) (lazy-seq (cons (do (println "twei") 2) nil))))] (first x))
16:20	clojurebot	1
16:20	clojurebot	ein
16:21	bartj	kotarak: I am sorry I don't get it
16:22	kotarak	bartj: the thing inside the lazy-seq is not evaluated until you actually access it.
16:22	kotarak	see in neotyk's example
16:22	kotarak	twei is not printed
16:22	kotarak	,(let [x (lazy-seq (cons (do (println "ein") 1) (lazy-seq (cons (do (println "twei") 2) nil))))] (second x))
16:22	clojurebot	2
16:23	clojurebot	ein twei
16:24	kotarak	bartj: in his first example twei is printed because it is evaluated in the same lazy-seq
16:24	neotyk	it was evaluated by cons
16:24	neotyk	not lazy-seq
16:28	neotyk	bartj: does it makes sense?
16:29	bartj	, (let [x (cons 1 (cons 2 nil))] (second x))
16:29	clojurebot	2
16:29	bartj	er, same result without the lazy-seq?
16:30	neotyk	bartj: yes, but sideeffects are missing
16:30	tomoj	,(take 10 ((fn fib [i j] (cons i (fib j (+ i j)))) 1 1))
16:30	clojurebot	java.lang.StackOverflowError
16:30	tomoj	:)
16:30	kotarak	bartj: no. not the same
16:30	neotyk	bartj: include side effects and do (first x)
16:31	kotarak	,(let [x (cons (do (println "eins") 1) (cons (do (println "zwei") 2) nil))] (first x)
16:31	clojurebot	EOF while reading
16:31	kotarak	,(let [x (cons (do (println "eins") 1) (cons (do (println "zwei") 2) nil))] (first x))
16:31	clojurebot	1
16:31	clojurebot	eins zwei
16:31	kotarak	bartj: compare to lazy-seq example with first
16:31	bartj	, (let [x (cons (do (print "test") 1) (cons 2 nil))] (first x))
16:31	clojurebot	1
16:31	clojurebot	test
16:32	neotyk	,(let [x (cons (do (println "ein") 1) (cons (do (println "twei") 2) nil))] (first x))
16:32	clojurebot	1
16:32	clojurebot	ein twei
16:32	kotarak	,(let [x (lazy-seq (cons (do (println "ein") 1) (lazy-seq (cons (do (println "twei") 2) nil))))] (first x))
16:32	clojurebot	1
16:32	clojurebot	ein
16:33	kotarak	no "twei"
16:33	bartj	kotarak: yes!
16:35	bartj	I guess I was trying with the wrong examples!
16:58	bartj	tomoj: one need not mention the "exit" condition while writing a lazy-seq?
16:58	bartj	tomoj: that is a bit hard to get over at first
16:59	tomoj	that's part of the point of laziness
16:59	tomoj	(iterate inc 0) is the natural numbers, all of them
16:59	tomoj	but only as many as you need will be generated
17:01	tomoj	I've liked my eeepc but haven't tried any others, so..
17:02	tomoj	oops
17:02	tomoj	wrong channel
17:07	KirinDave	Did anyone ever make good on that lazy hash idea?
17:08	Cumbayah	Hi clojurians. Newb alert. What would be an ideomatic way of providing a lazy sequence over floats serialized to a file from java? thanks a bundle
17:09	KirinDave	Cumbayah: Check out lazy-seq
17:09	KirinDave	Cumbayah: It really works with I/O
17:11	Cumbayah	thx for the pointer
17:13	tomoj	then you end up with the stream left open if you don't consume the whole seq, though
17:14	KirinDave	tomoj: That is a problem with laziness.
17:14	KirinDave	Another possibility is to eat the file entirely into memory
17:14	KirinDave	But if you're making a lazy seq it's probably because the file is ginormous.
17:14	KirinDave	In that case, you need to make sure the stream is closed. preferably by a finally clause.
17:14	Cumbayah	potentially huge files, want to avoid reading into mem as it can be processed sequentially
17:15	KirinDave	Cumbayah: So just be aware that the file can close. And if you close the file while the lazy seq has it, it'll chuck an exception.
17:15	KirinDave	Lazy seqs can handle streams, so it's fine.
17:15	tomoj	avoiding holding the head will prevent keeping everything into memory, right?
17:15	KirinDave	Right
17:15	KirinDave	Or so I'm told
17:16	arkahn	I'd like to (doall map prn (line-seq rdr)) and catch the IOException so I could continue reading the file at a later time, i.e. "tailing". What syntax would I use to specify java.io.IOException in the catch clause?
17:16	KirinDave	Cumbayah: The easiest example of a lazy-stream is something like iterate
17:16	KirinDave	Cumbayah: (defn forever [start] (lazy-seq (cons start (forever (inc start)))))
17:16	arkahn	the prn will be replaced with another fn
17:16	KirinDave	So (take 5 (forever)) is (0 1 2 3 4)
17:17	hiredman	clojurebot: exceptions?
17:17	clojurebot	http://paste.lisp.org/display/74305
17:19	bartj	for this function:
17:19	bartj	,(defn my-iterate [f x] (lazy-seq (conj [x] (my-iterate (f x)))))
17:19	clojurebot	DENIED
17:19	bartj	why can't I do a - (my-iterate inc 0)
17:21	KirinDave	bartj: Why conj?
17:21	KirinDave	bartj: But anyways, note that you're passing (my-iterate (f x))
17:21	KirinDave	Which is wrong
17:21	KirinDave	I think you meant
17:22	KirinDave	(my-iterate f (f x))
17:23	bartj	KirinDave: my knowledge of clojure functions is a bit limited
17:23	bartj	yes, you are right
17:23	KirinDave	bartj: I don't know why you're putting everything in a vector.
17:23	KirinDave	See my previous code for something like iterate
17:23	bartj	but, I use lazyseq and still get a stackoverflow
17:24	KirinDave	Try
17:24	KirinDave	(defn my-iterate [f x] (lazy-seq (cons x (my-iterate f (f x)))))
17:24	KirinDave	And then say (take 5 (my-iterate inc 0)))
17:24	KirinDave	err, ))
17:25	KirinDave	Infinite seqs are like hot lava. Unless you set up your repl to handle them, they're gonna burn you upon contact. :)
17:25	naeu	hot java lava
17:27	ninjudd	if i have an implementation of a protocol method that is the same for two different calls to deftype, what is the appropriate way to keep the code dry?
17:27	ninjudd	should i just call deftype without the protocol and then use extend, merging my methods into a hash of the default implementations?
17:28	naeu	ninjudd: is it possible to defn the method and pass the method name to deftype?
17:28	bartj	thank you all for helping me write my first lazy-seq
17:29	ninjudd	naeu: oh, does that work?
17:29	naeu	ninjudd: I have absolutely no idea :-)
17:29	naeu	'twas but a guess
17:30	ninjudd	i'll try it
17:33	ninjudd	naeu: i can't do what you suggested, but i can call the method from my implementation, though that results in an extra method call, rather than calling my implementation directly
17:34	naeu	hmm that's frustrating
17:35	naeu	I wonder what the speed difference actually is
17:36	naeu	it would be interesting to do some performance tests
17:36	naeu	perhaps hotspot optimises away that extra method call
17:37	ninjudd	yeah, i doubt the performance hit would be significant. i'm more concerned with what the generally accepted idiom is for doing it
17:38	naeu	ninjudd: I wonder if an idiom has had chance to form yet...
17:38	naeu	:)
17:41	ninjudd	clojure.contrib.io uses extend to share implementation: http://github.com/richhickey/clojure-contrib/blob/master/src/main/clojure/clojure/contrib/io.clj
17:41	ninjudd	but it doesn't use deftype
17:43	ninjudd	chouser: do you know what the right way to share implementation with deftype is?
17:43	kotarak	ninjudd: using extend with a map and eg. merge
17:45	ninjudd	kotarak: ok, so just call deftype and leave the protocol out, then do extend
17:45	kotarak	ninjudd: yes
17:45	ninjudd	kotarak: cool, thanks
17:47	ninjudd	kotarak: the deftype fields won't be accessible directly to those methods, right? or will they?
17:47	kotarak	ninjudd: you'll have to use (.field instance)
17:48	arkahn	I'm in the process of writing something that tails a file. Can anyone tell me why the following exits when it 'should' infinitely loop? http://gist.github.com/421550
17:48	ninjudd	kotarak: k
17:49	kotarak	arkahn: because repeatedly is not a loop. It create a lazy sequence, which gets never realised.
17:49	kotarak	You probably want loop/recur or so
17:49	kotarak	Or (while true ...)
17:49	arkahn	kotarak: oh - ok, thank you
17:59	DeusExPikachu	is there a function that simply executes its argument? similar to how identity simply returns its argument? basically a name for #(%)?
18:01	turbofail	,(apply (fn [] "Foo"))
18:01	clojurebot	java.lang.IllegalArgumentException: Wrong number of args passed to: core$apply
18:01	turbofail	doh
18:01	turbofail	works on my older version of clj
18:02	bartj	DeusExPikachu: what do you mean by simply execute?
18:02	raek	,(apply (fn [] "Foo") [])
18:02	clojurebot	"Foo"
18:02	DeusExPikachu	#(%)
18:02	DeusExPikachu	basically a name for that
18:03	turbofail	is there some reason you need a name for it?
18:04	DeusExPikachu	clarity, readability, nothing more really
18:04	turbofail	well, you could always make one
18:04	tomoj	hrmm
18:04	tomoj	so you have foo and you're doing (#(%) foo) ?
18:04	DeusExPikachu	I know I can, just wanted to know if there was one already in core
18:05	turbofail	the closest thing is "apply," but that requires an extra arg
18:05	DeusExPikachu	tomoj, no, more like (map #(%) vector-of-fns)
18:05	tomoj	ah, I see
18:06	tomoj	((apply juxt vector-of-fns)) heh
18:08	defn	http://gist.github.com/421584
18:08	defn	how can I turn that lazy-cons into a lazy-seq
18:09	tomoj	I think lazy-cons is (lazy-seq (cons ...)) ?
18:09	defn	yeah that sounds right
18:09	defn	not sure if the if needs to be inside though
18:10	tomoj	nope
18:10	defn	k cool, thanks
18:10	defn	need to get my markov on :)
18:16	bhenry	is there a function to which i can pass a symbol (representing a function) that tells me what namespace said symbol is defined?
18:17	tomoj	no
18:20	lancepantz	stuarthalloway: there was a discussion in the mailing list about splitting up contrib into individual jars, do you see this happening?
18:20	stuarthalloway	lancepantz: yes
18:20	tomoj	bhenry: can you maybe give an example of what you want?
18:20	lancepantz	that will be awesome
18:20	stuarthalloway	lancepantz: but not before beta1
18:21	lancepantz	but before 1.3?
18:26	bhenry	tomoj: a project uses all kinds of namespaces eg ns1 . . . ns10
18:27	bhenry	tomoj: i look through the project and see (fn-1 some stuff here)
18:27	bhenry	i was wondering if i could do (somefunc fn-1) to see what namespace it was in
18:28	tomoj	aha, in that case, yes
18:29	tomoj	,(resolve '+)
18:29	clojurebot	#'clojure.core/+
18:30	bhenry	haha derrr. doc will do it too
18:30	tomoj	yeah, that too
18:30	tomoj	best to use require or use :only, I think
18:30	tomoj	I mean, :require or :use :only
18:31	bhenry	yeah. i didn't write this project. but that seems like a good practice to adopt
18:33	tomoj	best for the people who will have to read your code later :)
18:37	bartj	trying to write a lazy-seq for generating prime numbers
18:38	bartj	and realized that I would have got the field's medal or something similar if I could write one....
18:38	bartj	FML
18:38	tomoj	where's my field's medal? :(
18:39	bartj	tomoj: I mean there is no function which will predict the next prime number, right?
18:39	tomoj	sure there is
18:40	bartj	hmm?
18:40	bartj	which is?
18:40	tomoj	the simplest example is the function that just keeps looking until it finds another prime..
18:41	defn	bartj: depends on what you mean by predit
18:41	defn	predict
18:42	defn	i could conceive of a function which guesses the next prime, but isn't always accurate
18:42	tomoj	but why bother when we can just make a function which is always accurate?
18:43	defn	shrug -- maybe for massive primes it's not a terrible idea to try
18:43	tomoj	oh, yeah, for massive primes my simple function will just run until you die
18:43	defn	:)
18:44	bartj	(defn is-prime? [x] (loop [i 2] (if (>= i x) true (if (= (rem x i) 0) false (recur (inc i))))))
18:47	candera	IIRC there are algorithms that can be run to determine with a lower bound on the probability that a number is prime. So if you're cool with a sequence of numbers that is highly likely to be prime, you could pull that off.
18:47	tomoj	I don't understand
18:47	tomoj	we can write a function which returns a lazy seq of all and only the prime numbers
18:48	candera	But it's horrendously inefficient to use the Sieve of Erasthenese.
18:48	tomoj	so what?
18:49	candera	If you only need the first n, for small n, then yep, so what?
18:51	bartj	(defn get-primes [] (lazy-seq (is-prime? (iterate inc 2))))
18:52	tomoj	,(doc filter)
18:52	clojurebot	"([pred coll]); Returns a lazy sequence of the items in coll for which (pred item) returns true. pred must be free of side-effects."
18:52	bartj	returns an error of - clojure.lang.Cons cannot be cast to java.lang.Number
18:52	candera	(defn get-primes [] (filter is-prime? (iterate inc 2))
18:53	bartj	candera: I was enthusiastic to use lazy-seq
18:54	bartj	also why doesn't (take 5 (get-primes)) work?
18:54	tomoj	you will rarely need to use lazy-seq
18:55	bartj	tomoj: why not in the above case?
18:56	tomoj	iterate already returns a lazy seq
18:57	tomoj	(take 5 (get-primes)) should work
18:58	bartj	clojure.lang.Cons cannot be cast to java.lang.Number
18:59	tomoj	candera corrected your get-primes
19:00	tomoj	is-prime? expects a number, you were passing (iterate inc 2) to it, not a number
19:04	bartj	tomoj: yes, thank you
19:11	nirly	where do I need to put clojure files so I can load them with (require )?
19:18	tomoj	nirly: on the classpath
19:18	hiredman	require works on namespaces, and tries to map those namespaces to files, so if your namespaces and filenames map to each other correctly require will work
19:19	hiredman	~namespaces
19:19	clojurebot	namespaces are (more or less, Chouser) java packages. they look like foo.bar; and corresponde to a directory foo/ containg a file bar.clj in your classpath. the namespace declaration in bar.clj would like like (ns foo.bar). Do not try to use single segment namespaces. a single segment namespace is a namespace without a period in it
19:19	tomoj	just use leiningen :P
19:21	hiredman	if you just want to load a file, there is, well, a function called load-file
19:22	jashmenn	is there a way i can pass a list "unpacked" to a function. like the splat* operator in ruby?
19:26	lancepantz	jashmenn: apply
19:26	lancepantz	,(apply println '("a\n" "b\n" "c\n"))
19:26	clojurebot	a b c
19:26	jashmenn	lancepantz: ah, right thanks!
19:27	lancepantz	that makes more sense at a repl )
19:27	lancepantz	:)
19:42	kensanata	I know very little of Java and Clojure; working on my first piece of code and getting java.lang.IllegalArgumentException: No matching ctor found for class javax.swing.JPanel for this code: (import '(javax.swing JPanel ImageIcon)) (def tile (JPanel. (ImageIcon. "empty.png"))) -- what am I doing wrong?
19:48	technomancy	kensanata: ctor means constructor, so apparently you can't construct at JPanel with an ImageIcon argument.
19:49	kensanata	Gah, I think I confused JPanel with JLabel... Must try again.
19:50	kensanata	That was it. Thanks for the pointer, technomancy. :)
20:27	nuba	guys, i have this centos 5.5 32 bit which i'm migrating from vmware server into a xen running on a centos 5.5 64bit, how should I go about it, regarding kernel and para or hvm?
20:27	nuba	the part about converting the disk image with qemu-img is sorted out already
20:28	nDuff	nuba, are you sure this is the channel you mean to be in?
20:29	nuba	aww crap, sorry guys, dammit
20:29	nDuff	nuba, (Xen's HVM is pretty slow, unlike KVM's; PV will require more work, but is likely worthwhile)
20:29	nuba	wrong window, i thought i had switched irssi to #xen
20:30	nuba	heh, and that's from someone using irssi for 10+ years, sorry folks
20:31	axi	anybody know why "(import ('java.io File))" isn't working with enclojure?
20:31	tomoj	(import java.io.File)
20:32	axi	ty
20:32	axi	strangely it works in repl 1.1.0
20:33	axi	hrm yeah, (import 'java.io.File) works
21:37	pedroteixeira	hello, any way to keep running tests automatic just with clojure.test?
21:49	cemerick	pedroteixeira: you mean similar to infinitest or autotest?
21:49	cemerick	I don't know of anything like that yet, no.
21:49	cemerick	Would be pretty simple to do though.
22:06	pedroteixeira	cemerick: ok, thanks. i found stuarthalloway's circumspec now, will try to do something to watch and run-tests when things change,.
22:14	Siasia	test
22:15	Siasia	Oh! Hi there!
22:15	Siasia	I have some troubles with leiningen and swank
22:15	Siasia	Doesn't even know whats up? Just starting with clojure.
22:16	tomoj	what are your troubles
22:16	Siasia	can i drop stacktrace in here
22:16	Siasia	?
22:17	Siasia	that project clj
22:17	Siasia	(defproject sandbox "1.0.0-SNAPSHOT"
22:17	Siasia	:description "FIXME: write"
22:17	Siasia	:dependencies [[org.clojure/clojure "1.1.0"]
22:17	Siasia	[org.clojure/clojure-contrib "1.1.0"]]
22:17	Siasia	:dev-dependencies [[swank-clojure "1.2.0"]])
22:18	Siasia	just an empty lein new
22:19	Siasia	http://pastebin.com/iestTgzW
22:19	Siasia	and console session
22:19	tomoj	hrmm
22:19	Siasia	so lien swank is not warking
22:20	tomoj	never seen that error before there
22:20	Siasia	oh i'm on freebsd
22:20	Siasia	also i tryed swank with maven and its working perfectly
22:21	tomoj	hurrah
22:22	tomoj	that project.clj works fine for me
22:23	hiredman	Siasia: you want lein-swank not swank-clojure
22:23	tomoj	oh, I see what the problem is
22:23	tomoj	perhaps
22:24	hiredman	tomoj: well to start with
22:24	tomoj	Siasia: can you do (System/getProperty "os.name") and (System/getProperty "os.arch") ?
22:25	hiredman	Siasia: doesn't matter
22:25	hiredman	er
22:25	hiredman	tomoj
22:25	tomoj	I thought we want swank-clojure not lein-swank nowadays
22:25	tomoj	hiredman: why do you think it doesn't matterL
22:25	hiredman	oh
22:25	hiredman	right
22:26	hiredman	I thought it was the reverse
22:26	tomoj	I think this is what's causing the error...
22:26	hiredman	tomoj: what?
22:26	tomoj	Siasia's os.name or os.arch aren't known by leiningen
22:26	Siasia	i was afk
22:26	Siasia	so
22:27	hiredman	tomoj: I highly doubt that
22:27	tomoj	well, the stacktrace seems pretty clear to me
22:27	Siasia	user=> (System/getProperty "os.name")
22:27	Siasia	"FreeBSD"
22:28	tomoj	exactly
22:28	Siasia	user=> (System/getProperty "os.name")
22:28	Siasia	"FreeBSD"
22:28	tomoj	native-names in compiler.clj has no key for FreeBSD
22:28	Siasia	sorry
22:28	tomoj	and thus the NullPointerException
22:28	Siasia	so how can i work this around?
22:29	tomoj	maybe you can override os.name? :/
22:29	tomoj	I think you should report this, but don't know where leiningen bugs are reported
22:29	Siasia	and how can i pass this to lein?
22:29	tomoj	I don't know any way to do that, sorry
22:30	Siasia	any solutions?
22:30	tomoj	the only one I can think of is to fix leiningen
22:31	Siasia	kinda
22:32	tomoj	I believe adding "FreeBSD" :freebsd to the native-names map should fix your problem
22:32	tomoj	but maybe leiningen should not explode on an unknown os.name..
22:32	hiredman	technomancy is kind of a linux snob
22:33	hiredman	I've been trying to tell him to use something other than #!/bin/bash in the shebang for lein for a while
22:34	tomoj	Siasia: your best bet may be to follow the directions under "Hacking" in the leiningen readme and make the patch
22:35	Siasia	mokay. already cloning lein :)
22:44	Siasia	yep that's working
22:44	cemerick	why does lein care about the os.name?
22:52	tomoj	cemerick: native lib path
22:53	cemerick	really
22:53	tomoj	ayup
22:54	cemerick	not sure what to think of that
22:54	axi	when I create a class using ns/gen:class.. how do I expose variables
22:58	axi	:gen-class*
23:10	tomoj	you need to access these variables from java I guess?
23:11	axi	hrm.. gen-class :exposes only works for inherited protected members :(
23:11	axi	tomoj, i'd like to be able to do both
23:12	axi	access from java code and other clojure namespaces
23:13	tomoj	does :state not do what you want?
23:16	axi	how would I make use of that?
23:17	axi	(. instance state member) - unable to resolve symbol
23:17	tomoj	in the gen-class, you do like :state foo
23:17	axi	I did
23:17	tomoj	then (.foo instance)
23:18	axi	No matching field found
23:19	cemerick	axi: do you have an :init function that sets the :state?
23:20	axi	no
23:20	axi	i have
23:20	axi	(ns x.y (:gen-class :state state :init init))
23:20	axi	(defn -init [] ...code... )
23:22	cemerick	that should work
23:22	tomoj	but what does -init return?
23:22	cemerick	regardless of that, he shouldn't be getting 'no matching field'
23:23	cemerick	if -init returns an 'improper' value, the :state field will just be nil
23:24	cemerick	axi: are you compiling the relevant namespace, and then starting a new repl with the classpath appropriately set up to be able to load the AOT-compiled class?
23:34	tomoj	so you can only have one state field?
23:34	cemerick	in gen-class, yes
23:35	tomoj	I guess it is only really meant to store a ref/atom/whatever?
23:35	cemerick	you can drop any object there if you so choose
23:35	tomoj	but the fact that it's final and there's only one...
23:35	cemerick	right, it leads you to certain good defaults
23:36	cemerick	deftype and defrecord are there and quite preferable unless you really need gen-class' interop features
23:36	tomoj	what if you wanted to implement the state object in clojure?
23:37	cemerick	how do you mean?
23:37	tomoj	maybe what I'm asking is, what tools would we use to write refs/atoms in clojure
23:37	cemerick	ah, that's exactly what deftype is for
23:37	tomoj	deftype doesn't give you something java can hook onto, does it?
23:38	tomoj	or does it, hmm
23:38	cemerick	it emits fields
23:38	cemerick	far better to define an interface and implement that in the type IMO
23:38	cemerick	for java interop, that is
23:39	cemerick	field access is quite non-idiomatic in java
23:39	tomoj	but then how does java get ahold of an actual concrete class
23:39	cemerick	AOT-compile a deftype, and you've got a class
23:39	tomoj	ah, yes, ok
23:39	tomoj	only, it can't subclass anything
23:39	cemerick	right
23:40	cemerick	extending concrete subclasses opens up a whole can of worms. That's why gen-class is sticking around.
23:40	tomoj	so if the java lib you're working with defines it's plugin api in terms of abstract classes instead of interfaces, you're out of luck
23:40	cemerick	(and proxy, for that matter)
23:40	tomoj	oh, can we use deftype with abstract classes?
23:40	cemerick	no
23:40	tomoj	but it would be less of a can of worms than extending concrete classes?
23:41	tomoj	I wish I could somehow sneak deftype into the system
23:41	cemerick	sorry, I meant any class
23:41	tomoj	ah
23:41	cemerick	as opposed to interfaces
23:42	tomoj	I feel like there should be universal pressure on jvm developers to define their shit in terms of interfaces not abstract classes
23:42	cemerick	If you need the full-boat java interop, that's what gen-class and proxy are for.
23:42	cemerick	yeah
23:42	cemerick	Lots of history there.
23:42	tomoj	maybe there is some reading material
23:43	tomoj	I want to know why solr uses abstract classes
23:43	cemerick	probably because lucene uses abstract classes
23:43	cemerick	:-P
23:43	cemerick	godawful choice that was
23:43	tomoj	is there something you gain in java for using abstract classes?
23:43	hiredman	you can inheriting implementation
23:43	cemerick	default implementations
23:45	tomoj	I see
23:45	gstamp	I was wondering if anyone could suggest a good way to avoid repeating the call to key-pressed? in the code at http://codepad.org/ZeqvTmut. condp seems to be almost what I want but I'm not sure how I'd make it apply to this particular case.
23:45	tomoj	so maybe what java devs should do is define public interfaces and use them all over, but use abstract classes internally?
23:45	tomoj	(if needed)
23:45	cemerick	That's the ideal, yeah.
23:46	tomoj	I guess this style is evident in clojure's java sources, eh?
23:46	tomoj	never thought much about the I's and A's there
23:47	tomoj	wonder how much work it would be to fix solr and lucene :(
23:48	cemerick	tomoj: never, ever, ever going to happen :-)
23:49	tomoj	nooo
23:49	tomoj	this is just a nightmare I will wake up from soon