#clojure – 2009-05-02

2009-05-02

03:30	yason	Hmmm, did Clojure have a function/idiom to join a list of strings together with a glue string? Java doesn't seem to have one!
04:02	unlink1	str-join?
04:03	yason	unlink1: sounds like it but it isn't in the API index
04:04	unlink1	http://code.google.com/p/clojure-contrib/wiki/StrUtilsApiDoc#str-join
04:05	yason	oh, the contrib repository
04:06	yason	thank you, i should remember that more often :)
04:12	cgrand	yason: or (apply str (interpose \- ["hello" "world"]))
04:12	cgrand	,(apply str (interpose \- ["hello" "world"]))
04:12	clojurebot	"hello-world"
11:49	Chousuke	:)
11:59	unlink1	Might I also recommend switching to mercurial? ;-)
12:21	jboner	hg over git, no
12:24	Raynes	jboner: Woar.
12:31	AWizzArd	Ah, again hg vs git? ;)
12:31	AWizzArd	This whole discussion could be ended by a sweet version control system written in Clojure :)
12:31	Raynes	I haven't even installed a VCS yet.
12:31	Chousuke	hg is fine, but I like having control over what branches I publish from a repo. :/
12:32	AWizzArd	I like to have different branches in different repos, and decide which of those repos I publish
12:32	Chousuke	with hg it seems I'd have to clone the repository every time I want a private branch... acceptable I guess, but not the way I want to work.
12:32	Chousuke	well, git obviously supports that as well :)
12:34	Chousuke	there's just rarely any need to clone a local repository because you can just branch.
12:45	AWizzArd	Chousuke: it is very simple with hg and the typical workflow
12:45	AWizzArd	hg supports hard links, so those repositories won't eat much HD space
12:45	Chousuke	git does too
12:45	AWizzArd	in googles analysis they only noticed that git repos are bigger than hgs
12:46	AWizzArd	So, that speaks more for hg in my opinion.
12:46	AWizzArd	It is trivial to start a new repo, and the hosting services provide tools for that.
12:46	Chousuke	bigger?
12:46	AWizzArd	as in "more hd space is used"
12:46	Chousuke	I thought they were about the same size.
12:47	AWizzArd	probably not huge differences
12:47	AWizzArd	what surprised me was that cloning via http is much faster with hg
12:47	AWizzArd	Google measured about 8 seconds for their test repo with hg
12:47	AWizzArd	and 178 seconds with git
12:47	Chousuke	yeah, that's one thing hg has for it.
12:48	Chousuke	git has no good protocol for http cloning.
12:48	AWizzArd	Anyway, from the technical point of view both are too similar to see an obvious better candidate
12:48	Chousuke	they'll probably fix it in some future version though.
12:48	Chousuke	actually the first benchmark I find with google regarding repo size shows that git repos are smaller :/
12:49	Chousuke	but it's almost a year old. maybe hg has improved.
12:50	Chousuke	http://vcscompare.blogspot.com/2008/06/git-mercurial-bazaar-repository-size.html anyway
12:50	AWizzArd	I think yes
12:51	Raynes	I can't believe I managed to spark a conversation about VCS's simply by saying I had switched to Linux. :o
12:51	AWizzArd	Raynes: yeah, good job
12:51	Chousuke	:P
12:51	Chousuke	Raynes: you mentioned git.
12:51	Chousuke	that's enough.
12:51	AWizzArd	if it is silent here mention git
12:52	Raynes	"What are the benefits of using Git?" I bet that phrase would make people talk in here who have never talked before.
12:53	AWizzArd	I think git has won the popularity thing
12:53	AWizzArd	For example in #git there sit around 500+ people, while in #mercurial we have 120 or so
12:53	AWizzArd	But this does not seem to reflect the technical capability
12:54	Chousuke	git and hg are both good. I just think git is a bit better
12:54	AWizzArd	For example git hosts as its maybe biggest project the Linux kernel with over 2,5 mio LOC
12:54	AWizzArd	hg has Mozilla with around 2,3 mio LOC
12:54	Raynes	:o
12:55	Chousuke	X.org uses git too
12:55	clojurebot	git is http://www.github.com
12:55	AWizzArd	and not to forget OpenSolaris. Alone the OpenJDK has 6,5 mio LOC. So from that it seems that hg is capabale of holding big code bases.
12:55	Chousuke	though X is modularised into several repos nowadays
12:56	AWizzArd	Would be cool if Rich would switch to hg which is now available on Google.
12:56	Chousuke	I wouldn't mind that at all :)
12:56	AWizzArd	I also already said: if the choice is hg or git instead of svn, then both options are a win
12:56	Chousuke	yeah :P
12:57	AWizzArd	But Rich will also have tool support in mind
12:57	AWizzArd	technicaly speaking hg and git seem to be very similar
12:58	AWizzArd	In 2010 someone will start Clojanarian - the next VCS
12:58	Chousuke	:P
13:00	Raynes	Yes, I will, and it will be called Verjure.
13:03	Raynes	Or, Jursion. JCS Jursion Control System.
13:06	Raynes	CVCS Clojure Version Control System.
13:07	Drakeson	just build a java/clojure version that reads and writes to the .git directory and uses git protocols, and everyone will be happy.
13:08	Chousuke	you mean http://www.jgit.org/ ? :P
13:08	Raynes	But, I'd rather just trump Git in general.
13:10	Drakeson	does it work well, then?
13:10	Drakeson	is it actively maintained?
13:13	alvivi	http://hgbook.red-bean.com/read/preface.html#id412633 more git vs hg flame :P
13:14	Chousuke	and out of date :P
13:30	AWizzArd	That Google decided to go with hg tells a lot :)
13:32	Drakeson	such as it is easier to deploy hg in a python environment
13:32	Drakeson	not to forget that they have a great set of tools around git (gerrit, etc.)
13:38	AWizzArd	So git as a set of C programs and shell scripts can make sense for the Linux kernel
13:39	unlink1	Why do I get a reflection warning from (defn f [o] (.toString o))?
13:39	AWizzArd	but things like Mozilla and the OpenJDK or Python decided to go the hg route.
13:40	AWizzArd	I think at compile time it is not obvious which .toString method needs to be called
13:40	Chousuke	I suppose for those projects, windows support is essential.
13:40	Chousuke	also in google's case, HTTP cloning.
13:40	Chousuke	not to mention they are very familiar with python :P
13:41	AWizzArd	unlink1: Clojure cannot insert a direct call to the right .toString. Only at runtime we know which of the many thousands .toString is the right one.
13:41	AWizzArd	The OpenJDK guys? ;-)
13:42	hiredman	unlink1: you need to type hint o
13:42	unlink1	Doesn't everything have toString?
13:43	Chousuke	AWizzArd: google
13:47	AWizzArd	funnily googles Android project..
13:47	Chousuke	what about it?
13:47	AWizzArd	it's under git
13:47	Chousuke	heh.
13:47	Chousuke	maybe they decided git was better for it :P
13:48	AWizzArd	Oh well, possible. In the end I don't care too much. I used git for some months, now switched for hg (because I like that working style more and find it easier to use). I can use both systems and have both installed.
13:48	AWizzArd	I hope they can divide the market fairly so that there is always some pressure on both teams to evolve their system.
13:49	Chousuke	I don't think that'll be a problem :)
13:51	AWizzArd	even if more people and projects decided to use git, I can still be happy that Mercurial has the cooler name
13:51	replaca	~seen hiredman
13:51	clojurebot	hiredman was last seen in #clojure, 9 minutes ago saying: unlink1: you need to type hint o
13:52	replaca	hiredman: I got some json for ya
13:53	replaca	hiredman: http://clojure-contrib.googlecode.com/svn/wiki/ApiDocIndex.json
13:53	dreish	unlink1: It looks like Clojure just spits out reflection warnings on non-type-hinted objects without exception. If you type hint it as #^Object (which provides no actual information; everything is an Object), the warning goes away.
13:56	replaca	1/4 MB on a single-line, since c.c.json.write doesn't seem to know any other way
13:56	danlarkin	replaca: clojure-json does :) It can do indenting!
13:56	replaca	danlarkin: cool, maybe we should pull that behavior into contrib
13:57	replaca	I was thing I'd just write a pp dispatch table rather then replicating the indenting logic everywhere
13:57	danlarkin	,(org.danlarkin.json/encode-to-str "[1 2 3 {\"a\" \"b\"} 4 5]" :indent 4)
13:57	clojurebot	"\"[1 2 3 {\\\"a\\\" \\\"b\\\"} 4 5]\""
13:57	danlarkin	well.. ok it doesn't indent on irc but you get the idea
13:57	hiredman	gnarly
13:58	danlarkin	,(org.danlarkin.json/encode-to-str [1 2 3 {"a" "b"} 4 5] :indent 4)
13:58	clojurebot	"[\n 1,\n 2,\n 3,\n {\n \"a\":\"b\"\n },\n 4,\n 5\n]"
13:58	danlarkin	there we go
13:58	hiredman	replaca: I'll get on that tomorrow or next week sometime
13:58	replaca	but since it's for clojurebot anyway, I'm not sure it matters right this sec - I'll fix it up later
13:59	replaca	yup, no worries, I just wanted you to know it was ready when you are
13:59	replaca	I'm thinking I'll probably write some repl and slime tools to go with it too
14:00	replaca	so you can find doc without loading all the namespaces
14:00	Lau_of_DK	Good evening all
14:00	replaca	Hi Lau
14:01	replaca	I'm off to spend a rainy day at the museum looking at Andy Warhol paintings...
14:01	replaca	by all
14:01	replaca	bye all
14:01	replaca	having fun arguing git vs. hg!
14:05	Lau_of_DK	Guys - I remember technomancy talking about using thread-local vars when handling sessions for webusers on a jetty servlet - Anybody know how thats done ?
14:06	Chousuke	with-local-vars?
14:09	Lau_of_DK	Thanks big guy, I'll look into it
14:14	Quiark	Anyone has vimclojure working? I'm getting all sorts of seemingly random errors...
14:17	hiredman	vimclojure is sensitive about having a correct namespace declaration
14:17	hiredman	and the namespace has to be on the classpath of the nailgun server
14:18	Quiark	yep, I think I have that correct
14:18	hiredman	are you sure?
14:18	Quiark	I restarted vim once more and now it works without changing anything...
14:19	hiredman	shrug
14:19	Quiark	I'm using the svn head version of clojure, so if its unstable, it could be the cause
14:22	hiredman	nope
14:22	hiredman	unless you wait months between checkouts
14:23	Quiark	I just started using clojure, so I have yesterday's checkout :)
14:24	hiredman	~latest
14:24	clojurebot	latest is 1360
14:24	hiredman	r1360
14:26	Quiark	yes, 1360 is what I have
14:34	unlink1	I'm not sure exactly what warn-on-reflection accomplishes. It seems like it just complains if you use field/method accesses on an object which doesn't have a type annotation, and then is silenced when that object is given a type annotation, regardless of the type; but then fails at runtime if the field/method doesn't resolve.
14:36	dnolen	unlink1: it's telling you that the code will have to use reflection. This is a _massive_ performance hit.
14:36	hiredman	type hinting is just a sort of unsafe cast :P
14:37	unlink1	OK, so it says "cast to this type"?
14:37	hiredman	more or less
14:37	hiredman	so if the type doesn't have the corrent field or method at runtime boom
14:37	hiredman	correct
14:40	unlink1	so (fun x [#^String s] (.trim s)) corresponds to something like public static Object x(Object s) { String s = (String)s; return s.trim(); } ?
14:41	unlink1	Well I mean you can't shadow a parameter in java.
14:42	hiredman	I forget if casts have higher or lower presidence then method calls
14:42	hiredman	((String)s).trim
14:42	hiredman	();
14:42	unlink1	uh, . has the highest precedence I think.
14:44	unlink1	I actually never used reflection in Java.
14:45	unlink1	Interesting, you can access private fields with it?
14:46	unlink1	I guess that would be an important feature.
15:00	technomancy	is there a function like remove that takes an element to remove instead of a predicate?
15:03	cgrand	technomancy: (remove #{foo} coll)?
15:04	cgrand	(doesn't work with false and nil as usual)
15:05	technomancy	right; that's fine; thanks
15:23	lisppaste8	technomancy pasted "dir-seq" at http://paste.lisp.org/display/79555
15:23	technomancy	how would you write that without using "flatten"?
15:30	Drakeson	who mentioned jGit? it is a funny joke at the moment. It only has branch, clone, daemon, fetch, init, log, push, rm, tag, version.
15:32	Drakeson	I cannot imagine what can be done using those, other than just reading a git repo, and/or serving it.
15:33	technomancy	Drakeson: well it would be pretty silly to use a JVM-hosted tool for actually committing given the JVM's boot time
15:33	technomancy	but letting JVM-hosted apps read repositories could be pretty useful
15:34	Drakeson	technomancy: no it is not. you don't need to launch a new JVM for every operation. People are already looking for libgit to use git as a storge backend for whatever makes sense.
15:35	technomancy	Drakeson: still, there's very little advantage to JVM-hosting for day-to-day usage.
15:35	Drakeson	also, it is a matter of things not written yet. the have added the "push" command recently.
15:36	Drakeson	technomancy: unless you use a git repos as a persistence backend.
15:36	Drakeson	(again, for limited but important use cases)
15:37	technomancy	well it sounds like if you want to do that you'll have to write the commit functionality yourself. =)
15:37	eee	does anyone here use clojure-dev
15:39	Drakeson	The usage I have in mind is sharing libraries with source code. A central repository of git repositories for clojure libraries.
15:40	Drakeson	(with read-only operations a good portion of that can be done, though)
15:41	eee	i'm interested in mercurial before git
15:41	eee	personally
15:42	kadaver_	I'm gonna post my mp3player to the mailinglist
15:42	kadaver_	what is thge best format to post it?
15:43	kadaver_	Ie should I paste the code somewhere or upload .clj files?
15:43	Drakeson	eee: It is not a matter of which is functionally superior, anymore. Right now it only matters which one is being used by more projects.
15:44	eee	i use the same reasoning, and the eclipse plugin sucks
15:44	eee	and eclipse is awesome
15:45	eee	therefore ...
15:45	eee	but I haven't used mercurial yet
15:45	eee	just curious about it
15:45	eee	is all I was saying :)
15:47	kadaver_	git git git git
15:48	eee	lol
15:48	kadaver_	noone is curious about my mp3player
15:48	kadaver_	it has a weirdo bug
15:48	kadaver_	probably with threading :P
15:48	eee	kadaver_ i don't know how to answer other than to say to check into the github
15:48	eee	and then post to the group that you have a third-party
15:49	eee	and then rich can add it to the third party page
15:49	eee	or that would be my guess
15:56	technomancy	interesting comparison: http://bitbucket.org/repo/all/?name=clojure vs http://github.com/languages/Clojure
15:57	technomancy	2 pages vs 12 pages
15:58	eee	i never heard of bitbucket
15:58	eee	to support your argument
15:58	eee	which one is older?
15:58	hiredman	can't say I am surprised that most clojure projects are following clojurebot's lead...
16:01	Drakeson	does github has a way to initiate a project right from the commandline, without going through the web interface?
16:06	Drakeson	What is the vision for lancet? Is it going to be a versatile dependency resolution and be able to obtain and track/update dependencies from external and local repositories?
16:11	technomancy	hiredman: heh
16:11	technomancy	Drakeson: yeah, you can initiate projects through the command line through github. the Jeweler project does that, and the "gh" gem might as well.
16:11	technomancy	Drakeson: Stu doesn't seem to be that interested in adding dependency resolution to lancet.
16:12	technomancy	I've been playing around with a prototype here: http://github.com/technomnacy/corkscrew ... doesn't support transitive deps yet, but it can pull jars from HTTP and projects from git/svn repos
16:18	Drakeson	Where do you put the jar files?
16:19	Drakeson	is it in ~/.m2 ?
16:45	technomancy	Drakeson: right now it uses ~/.corkscrew, but eventually it should integrate with mvn and use ~/.m2
17:55	Raynes	Business is picking up with severe weather here. :\ Tornado warnings.
17:55	Raynes	I don't like tornado warnings.
18:01	rsynnott	presumably better than un-warned-of tornados
18:10	kadaver_	there is no function like reduce-and-add-to-end?
18:12	unlink1	What's the idiomatic way of taking a list and an object and returning the list with the object appended (i.e. to the end of the list)?
18:12	unlink1	Like conj but at the end of the list.
18:14	Chousuke	,(concat '(1 2 3) (list 4)) ; this is probably as idiomatic as you can get.
18:14	clojurebot	(1 2 3 4)
18:14	AWizzArd	You should just be aware that this is O(n)
18:14	Chousuke	it's lazy, actually :)
18:14	AWizzArd	If you need that then maybe lists are not the right datatype for the task at hand.
18:14	Chousuke	so it's only O(n) if you traverse the list.
18:15	Chousuke	in which case it would be O(n) anyway :)
18:15	unlink1	I'm not too worried, I don't expect n > 4 or 5.
18:15	Chousuke	anyway, vectors would be more idiomatic
18:16	Chousuke	or well, I guess it depends on what you do with it.
18:16	unlink1	I'm trying to write a macro that does the same thing as -> except threads the return value as the last argument to the next function.
18:17	Chousuke	hmm, tricky.
18:17	kadaver_	the idiomatic way in clojrue is suing evctors...
18:18	Chousuke	but yeah, if it's a macro, performance doesn't matter much.
18:19	kadaver_	@paste
18:19	kadaver_	clojurebot: paste?
18:19	clojurebot	lisppaste8, url
18:19	lisppaste8	To use the lisppaste bot, visit http://paste.lisp.org/new/clojure and enter your paste.
18:20	lisppaste8	kadaver pasted "mp3-main" at http://paste.lisp.org/display/79566
18:20	AWizzArd	Chousuke: when does the concat gets fired off?
18:20	Chousuke	AWizzArd: immediately. it just returns a lazy seq
18:20	AWizzArd	Only when one touches the (to be concated) last element of the list?
18:21	Raynes	This is rare.
18:21	Raynes	116 people in here. 128 in #Scala.
18:21	Raynes	We normally trump that channel.
18:21	lisppaste8	kadaver pasted "guilogic" at http://paste.lisp.org/display/79567
18:22	lisppaste8	kadaver pasted "utils" at http://paste.lisp.org/display/79568
18:22	Chousuke	kadaver_: load-latest looks like it does IO. does it?
18:23	Chousuke	guessing from hte name :P
18:23	lisppaste8	kadaver pasted "database" at http://paste.lisp.org/display/79569
18:24	Chousuke	right, it does.
18:24	Chousuke	you can't do that in a transaction
18:24	arohner	spit and slurp both do I/O
18:24	Chousuke	it'll break.
18:25	Chousuke	I wonder if slurp and spit contain an (io!) block? :/
18:26	Chousuke	~source slurp
18:27	Chousuke	apparently not.
18:27	Chousuke	wonder if they should :P
18:28	cp2	i'll slurp you
18:31	aperotte	hi everyone
18:32	aperotte	I've been working on a new datatype for clojure and I posted my work so far up on github
18:33	aperotte	http://github.com/aperotte/persistentmatrix
18:33	aperotte	It's a matrix/n-dimensional array datatype, and would welcome any and all feedback
18:35	kadaver_	http://groups.google.com/group/clojure/browse_thread/thread/c0819f314391a311
18:35	kadaver_	^^ mp3player written in Clojure, thread in the google group, some info and comments on programming in clojrue + ofc the code.
18:36	kadaver_	it is ~400 LOC
18:38	kadaver_	I'd love comments on the code
18:39	Chousuke	aren't you using a version control system? :/
18:40	kadaver_	nah
18:40	Chousuke	you should
18:40	Chousuke	there's no reason not to use one :/
18:40	kadaver_	REAL programmers dont use version control systems
18:40	Chousuke	you're not a REAL programmer :)
18:40	kadaver_	they write one perfect program in ASM.
18:41	Chousuke	kadaver_: anyway, as I said, doing IO inside a dosync is generally not good
18:41	Chousuke	it might get retried.
18:43	Chousuke	have you even tested if that code works at all. because it looks like it won't :P
18:44	Chousuke	or hm.
18:45	Chousuke	never mind, I just forgot Ref does pass-through when in operator position
18:47	Chousuke	but you should do something like (let [latest (utils/load-latest (str (player-state :dir) "latest"))] (dosync (commute player-state assoc :playlist latest)))
18:49	Chousuke	alter works too, but looks like commute should do in that case.
18:49	kadaver_	it does
18:49	Chousuke	anyway, it's time for me to sleep. so good night. :)
18:50	kadaver_	alter vs commute?
18:54	Drakeson	How would you talk to a webserver (It needs POST, https).
18:55	Drakeson	I couldn't find anything for that in contrib
19:10	cgrand	technomancy: you can use tree-seq to avoid flatten (flatten being usually implemented with tree-seq), but file-seq looks very much like your dir-seq
19:12	Raynes	"What is linux?" :o
19:14	bradford	,(for [x (range 5)] x)
19:14	clojurebot	(0 1 2 3 4)
19:15	gnuvince_	bradford: alternatively, (range 5) ;)
19:15	bradford	gnuvince - just showing my friend the repl :-)
19:18	gnuvince_	ok
19:19	kadaver_	rhickey: are you opposed to static typing?
19:43	rlb	Does clojure already have something like a map for n-ary trees? i.e. map (fn [x] (* x 2)) over (1 (2 3)) to produce (2 (4 6))
19:53	Raynes	I hate the sound of tornado sirens.
20:33	AWizzArd	Drakeson: it depends on the complexity of your requirements
20:33	AWizzArd	You may want to consider htmlunit, if that fits your needs.
20:33	AWizzArd	http://htmlunit.sourceforge.net/
20:34	rlb	Can you index a map by a string, i.e. ("x" {"x" 42}) -> 42?
20:34	AWizzArd	,({"x" 1, "y" 2} "x")
20:34	clojurebot	1
20:34	rlb	I know maps are functions of their values for symbols at least.
20:34	rlb	oh, right
20:35	rlb	(thinking backward)
20:35	AWizzArd	rlb: only when you use keywords, such as :x or :my-keyword you can put them into the position of the function.
20:35	rlb	AWizzArd: I think that's what confused me.
20:35	rlb	Thanks
20:35	AWizzArd	,(:a {:a 1})
20:35	clojurebot	1
20:35	AWizzArd	there it works
20:40	rlb	I imagine there's probably a clever way to take f and '(x y z) and call (((f x) y) z).
20:54	ee	this should be easy, but how do you print "done" if a java object is null?
20:55	ee	I have (when (= nil heap) (println "done"))
20:55	ee	so what's the predicate for "isNull"
20:55	AWizzArd	,(doc nil?)
20:55	clojurebot	"([x]); Returns true if x is nil, false otherwise."
20:56	ee	i tried that
20:56	ee	i guess it's not null
20:56	ee	duh
20:57	ee	it ws null
20:59	ee	hmmm
20:59	AWizzArd	,(when (nil? nil) (print "done"))
20:59	clojurebot	done
21:00	AWizzArd	probably your heap was not nil at that time
21:00	ee	yeah
21:01	ee	it wasn't, but i was getting null pointer exception. but it was from inside the heap I guess
21:01	ee	thanks
21:01	ee	i think I figured it out
21:56	eee	i finally solved the problem with my heap. I'm glad I'm forcing myself to get through some gotchas
21:57	eee	my mistake was probably something pretty simple for a veteran java person.
21:57	eee	:)
22:00	eee	i was trying to break ties between user data associated with keys
22:00	eee	i mean associated with priorities
22:00	eee	so I call hashCode
22:00	eee	seems obvious now
22:13	technomancy	Drakeson: danlarkin and I are working on an HTTP client that may make it into contrib
22:13	technomancy	Drakeson: http://github.com/technomancy/clojure-http-client
22:14	technomancy	Drakeson: it does POST, but I don't know about https
22:15	eee	what's a longer description
22:15	technomancy	Drakeson: also check out the "resourcefully" branch for a higher-level wrapper.
22:16	eee	i see
22:17	eee	it's for programmatically accessing web pages?
22:17	technomancy	Drakeson: let me know if you end up using it; would like to hear what you think. obviously there's still a lot missing right now
22:17	technomancy	eee: more for REST-based APIs. if you just need to read a web page you can use slurp
22:17	eee	cool
22:18	technomancy	rather, use duck-streams; slurp might not do it
22:18	eee	oh i see in the test
22:18	technomancy	bbiab &
22:40	eee	glad to have learned about miglayout
22:40	eee	from that mp3 app
22:41	eee	posted to the user group