#clojure – 2010-01-31

2010-01-31

00:08	pdk	you could fuse them and be a hireddawg
00:09	abrooks	dawgedman
00:09	hiredman	:P
00:09	hiredman	I bring it up because I jost noticed kdawg_
01:44	technomancy	only one feature left before Leiningen 1.1.0
01:44	technomancy	wute
03:56	noidi	how can I create a double[][] in Clojure?
04:00	_ato	,(make-array Double/TYPE 10 10)
04:00	clojurebot	#<double[][] [[D@df090d>
04:00	noidi	thanks!
04:48	fholm	dmiller2718: you the guy who's working on clojure-clr ?
05:15	dr_df0	hi everyone
05:19	dr_df0	is anybody here?
05:19	dr_df0	are annotations supported now in clojure 1.1.0
05:19	dr_df0	I would like to use jboss netty library, but it requires annotations
05:25	_ato	no, they're not supported
05:27	dr_df0	do you know any other high performance socket server library for clojure?
05:27	dr_df0	socket-server from contrib is not suitable
05:27	dr_df0	since it creates thread for every connection
05:28	_ato	I'd just use NIO directly
05:29	_ato	I haven't heard of a clojure wrapper for it
05:29	_ato	there's a bunch of java NIO "frameworks" listed here: http://technfun.wordpress.com/2008/04/21/critique-of-java-nio-frameworks/
05:30	_ato	but they sound like overkill ;-)
05:30	dr_df0	+ato: thx
05:59	AWizzArd	Moin sys
08:02	noidi	is there something like assoc-in for conj?
08:02	noidi	I need to do this: {:foo [1 2 3]} --> {:foo [1 2 3 4]}
08:03	noidi	right now I'm tempted to make the value of :foo a ref just to make updating easier, but I know there must be a better way :)
08:04	Chousuke	noidi: updatein
08:05	Chousuke	with a dash :P
08:05	Chousuke	(doc update-in)
08:05	clojurebot	"([m [k & ks] f & args]); 'Updates' a value in a nested associative structure, where ks is a sequence of keys and f is a function that will take the old value and any supplied args and return the new value, and returns a new nested structure. If any levels do not exist, hash-maps will be created."
08:06	noidi	thanks!
08:06	noidi	that's exactly what I was looking for
09:02	AWizzArd	rhickey: is there a better/more performant way to do (= ::MyDefType (type obj))?
09:03	rhickey	AWizzArd: not really - why are you doing that?
09:05	AWizzArd	It is for my Clojure DB system. It can automatically create indexes during insertion, and for deftyped things it groups them by their type.
09:05	rhickey	ok, but why would it reference a type tag explicitly like that?
09:07	AWizzArd	Cause this can be the criteria for being taken into an index. The user can specify the criteria when to index something.
09:07	AWizzArd	And all objects one inserts that pass this test go into a specific index.
09:08	AWizzArd	(insert db obj) <-- this adds obj to all indexes for which obj pasess the index-predicate
09:09	AWizzArd	I just wanted to make sure that using = and type is the right thing.
09:09	rhickey	it will work
09:09	AWizzArd	good
09:09	AWizzArd	thanks
10:20	the-kenny	somnium: Does congomongo support mongo's modifiers? ($push $inc etc)
10:28	rrc7cz	has anyone implemented platform/plugin capabilities before?
11:22	satous	(doc assoc-in)
11:22	clojurebot	"([m [k & ks] v]); Associates a value in a nested associative structure, where ks is a sequence of keys and v is the new value and returns a new nested structure. If any levels do not exist, hash-maps will be created."
11:22	satous	(source assoc-in)
11:26	avarus	hi
13:54	AWizzArd	when I have a (deftype Foo [a b c]) and then (def x (Foo 10 20 30)), what name does have bar then? (bar x) ==> (:a :b :c)?
13:56	rhickey	AWizzArd: if you want map stuff, specify IPersistentMap and then you'll get support for (keys x)
13:56	rhickey	otherwise you have normal Java reflection of fields
13:56	AWizzArd	Ah sure, easy enough. I could have answered this myself. Thanks.
14:10	AWizzArd	Though it could be nice if Clojure offered its own reflection tools. Maybe this will be easier with clj-in-clj.
14:19	avarus	what's a simple template library for clojure in your opinion?
14:20	AWizzArd	avarus: template as in "html"?
14:20	avarus	yep
14:20	AWizzArd	did you look at Compojure?
14:21	avarus	oh, yes, I am just looking at it :)
14:21	AWizzArd	good choice
14:21	avarus	ok :)
14:22	avarus	I just set it up and it was very easy but I just tried the hello world for now :)
14:22	AWizzArd	This route makes sense.
14:29	avarus	the documentation is limited I think
14:29	AWizzArd	It is not optimal yet. The best thing is to start with the hello world and try to extend it a bit.
14:30	AWizzArd	Then the Google Group has code examples. There is a Wikibook with more examples.
14:31	AWizzArd	And a bit documentation you can find here: http://compojure.org/
14:31	avarus	ya, I'm there :)
14:32	avarus	the group seems to be full of info :)
14:32	avarus	the google group
14:32	AWizzArd	Compojure learning goes likes this: read the examples, modify them, play around with them, get an impression what you want to do, try to do it, begin asking questions in the GG.
14:32	avarus	:)
14:33	AWizzArd	after a few iterations Compojure will make very much sense. It is indeed pretty simple.
14:33	avarus	fine
14:37	avarus	cool, contrib has something for json :)
14:38	qbg	When I'm use `lein repl`, I can require my project, but when I using `lein swank`, I can't. What am I doing wrong?
14:41	AWizzArd	hi cg
15:08	robwolfe	qbg: "M-x swank-clojure-project" is probably what you need
15:09	qbg	I tried that and that also didn't work
15:09	robwolfe	do you have ":dev-dependencies [[leiningen/lein-swank "1.1.0"]])" in your project.clj?
15:09	qbg	Yes
15:11	Raynes	robwolfe: You don't need lein-swank in order to use swank-clojure-project.
15:12	robwolfe	Raynes: from swank-clojure.el "Note that you must have swank-clojure.jar in the lib/ directory"
15:12	Raynes	swank-clojure.jar isn't lein-swank.
15:13	robwolfe	Raynes: right, but I thought that lein-swank depends on it
15:14	dnolen	qbg: you probably need to compile lein-swank yourself. that's what I had to do to get it to work
15:14	dnolen	I believe that lein-swank in it's current release doesn't properly add the src to the classpath
15:14	dnolen	in the lein-swank directory
15:14	dnolen	lein uberjar
15:15	dnolen	then replace the lein-swank jar in the lib folder of your leiningen repo (I 90% sure you need to be using lein from source for any of this to work)
15:22	qbg	I built it and replaced the old one. Now it doesn't complain about the ^ reader macro, but I still can't require my project
15:24	robwolfe	qbg: slime starts ok, but you can not require your project?
15:24	qbg	Yes
15:25	qbg	It is just a classpath problem
15:25	robwolfe	what's the namespace of yoour project and how do you try to load it?
15:25	qbg	Currently it is called paradigmm (yes, a dumb name)
15:26	qbg	I currently call (require 'paradigmm) from the REPL to load it
15:26	qbg	This works just fine using lein repl
15:26	robwolfe	under "src" directory "paradigm.clj" with "(ns paradigm)"?
15:26	qbg	(add-classpath also works for loading it, but is non-ideal for other reasons)
15:26	qbg	Yes
15:27	qbg	The project directory was created with lein new
15:27	robwolfe	in "lib" do you see lein-swank-1.1.0.jar ?
15:29	qbg	yes
15:29	robwolfe	hmm... it works for me just fine
15:30	hiredman	don't use single segment namespaces
15:30	hiredman	foo.bar
15:31	qbg	Yeah, I need to come up with a better namespace name anyways
15:32	qbg	Most of the code is under paradigmm.<something> currently though
15:32	qbg	Hmm... If I remove lein-swank from leiningen's lib directory and the project's directory, and then run lein deps in the project directory, lein swank doesn't work, even though the lein-swank jar is copied to the project's lib directory
15:34	robwolfe	qbg: what error do you see?
15:34	qbg	"swank is not a task. Use "help" to list all tasks."
15:35	robwolfe	so you don't have lein-swank in project.clj dev-depdencies
15:35	qbg	But in my project.clj: ":dev-dependencies [[leiningen/lein-swank "1.1.0"]]"
15:36	robwolfe	try "DEBUG=1 lein swank" and see if there is "lein-swank.jar"
15:38	qbg	There is no lein-swank in the output, nor my project.
15:38	robwolfe	qbg: I hope you don't run "lein" script from Leinigen sources?
15:39	robwolfe	I mean I hope you copied this script to your "~/bin" for example
15:40	qbg	Grr...
15:40	qbg	Running lein-stable works; I have the lein script from the leiningen checkout symlinked to my ~/bin directory
15:40	robwolfe	wrong! :)
15:43	qbg	Hmm, the readme for leiningen says under Hacking: "When that finishes, symlink bin/lein from your checkout to your path. This will make "lein" run from your checkout while "lein-stable" uses the jar self-installed in ~/.m2."
15:43	qbg	This seems misleading then...
15:44	robwolfe	it's for hacking on Leiningen
15:45	robwolfe	for other projects just use lein-stable
15:47	qbg	The Emacs Integration page on github seems to implies that you need to be hacking on leiningen to use it
15:49	robwolfe	you just need "lein" script and "leiningen-standalone.jar" and that's it
15:49	robwolfe	and "clojure" of course ;)
15:50	qbg	The documentation seems misleading then
15:50	qbg	But now it works, so I'm happy
15:50	qbg	Now to subject myself to the pain of Swing...
15:55	avarus	good night
16:04	{aaron}	hi, i had a question about clojure...what, if anything, does clojure do about non-pure functions? do these matter, or affect assumptions clojure makes? e.g. if i want to, say, list files in a directory...that is a non-pure function... do i need to tell clojure that somehow?
16:04	thearthur	I'm trying to start a vpn(n2n) process through java.Runtime.exec and when the process starts in java the ioctl fails with "device or resource busy" when it starts form the shell it works??
16:05	hiredman	{aaron}: nope
16:05	thearthur	how does a process start by runtime.exec differ from a normal process
16:05	{aaron}	hiredman: so clojure doesn't cache results of functions, etc.?
16:06	hiredman	{aaron}: unless you use memoize
16:06	{aaron}	how about requirements for no side-effects in transactions?
16:06	hiredman	{aaron}: that is a practical requirement
16:06	{aaron}	that's my responsibility to ensure right?
16:06	hiredman	yes
16:06	{aaron}	ok
16:07	hiredman	you can use the io! macro
16:07	hiredman	,(doc io!)
16:07	clojurebot	"([& body]); If an io! block occurs in a transaction, throws an IllegalStateException, else runs body in an implicit do. If the first expression in body is a literal string, will use that as the exception message."
16:07	hiredman	but io! doesn't seem to be used much
16:07	{aaron}	i see
16:07	{aaron}	well, i guess it depends on whether the side effects are significant
16:08	{aaron}	i guess it's not really an "effect"
16:08	{aaron}	if i'm logging the time in a transaction, then i can't ensure the time is always going to be the same each try
16:08	hiredman	definitely not
16:09	hiredman	I think one possibility is to use an agent
16:09	hiredman	sends to agents inside a transaction don't happen until the transaction completes
16:10	hiredman	I believe the docs for agents also specify side-effect free functions, but it is common to ignore that
16:10	hiredman	,(doc agent)
16:10	clojurebot	"([state] [state & options]); Creates and returns an agent with an initial value of state and zero or more options (in any order): :meta metadata-map :validator validate-fn If metadata-map is supplied, it will be come the metadata on the agent. validate-fn must be nil or a side-effect-free fn of one argument, which will be passed the intended new state on any state change. If the new state is unacceptable, the validate-fn
16:10	hiredman	hmm
16:10	hiredman	,(doc send)
16:10	clojurebot	"([a f & args]); Dispatch an action to an agent. Returns the agent immediately. Subsequently, in a thread from a thread pool, the state of the agent will be set to the value of: (apply action-fn state-of-agent args)"
16:10	hiredman	I guess it doesn't specify that
16:13	{aaron}	i like the idea of be assured that functions can be side-effect free...but if there is no way to distinguish in the language...how do i know that mr. library author hasn't just implemented all of his library with the standard Java libraries and doesn't make guarantees about side-effects?
16:13	hiredman	you don't
16:14	rsynnott	in general, trusting that the library author is infallible is probably a bit over-optimistic :)
16:14	{aaron}	so then does programming functionally gain me anything? i'm only as pure as the code i rely on
16:14	hiredman	clojure emphasizes functional style with immutable values, but does not enforce it
16:14	{aaron}	hmm
16:15	{aaron}	ok. in other languages i guess they enforce declaring side effects or something?
16:15	rsynnott	{aaron}: well, if the library author SAYS their functions are side-effect fre, you can trust them or not
16:15	hiredman	{aaron}: well, I am pretty sure the only one that does is haskell
16:15	{aaron}	i see
16:15	rsynnott	just as when a glibc author says that function X won't segfault, you can trust them or not
16:15	{aaron}	right ;)
16:16	Chousuke	{aaron}: if the library author claims a function is pure, and it turns out not to be, file a bug :P
16:17	{aaron}	ok, another question - does clojure itself, separate from Java libraries, have the notion of side-effects...or does it just rely on the JVM for all IO?
16:17	Chousuke	hiredman: doesn't haskell have UnsafePerformIO or something that allows you to override the type system? :/
16:17	hiredman	Chousuke: no idea
16:17	Chousuke	I guess that's just an extension
16:18	hiredman	{aaron}: "just" is prejudicial, clojure is deigned to be integrated with the jvm
16:19	{aaron}	well, i'm trying to determine whether programming "only" in clojure guarantees pure functions...or whether there are intrinsically non-pure functions in clojure
16:19	Chousuke	there are.
16:19	{aaron}	(because then anything that imported stuff outside of clojure could automatically be labelled "dirty/sideeffects"
16:19	{aaron}	ok.
16:19	chouser	prn
16:20	chouser	builtin function that prints to stdout -- a side-effect.
16:20	Chousuke	but the host is such an integral part of the language that it doesn't make sense to consider Clojure without one :)
16:20	_ato	{aaron}: one of the main philosophies of Clojure is that pure-functional code, while having nice properties, is not always sufficient in a practical language. It allows side-effects but provides mechanisms (refs, atoms, agents etc) for making them safer.
16:20	Chousuke	it doesn't have to be the JVM though, but I guess that will always be the "main" Clojure host
16:21	{aaron}	ok. i assume the culture is such that when something has to have side effects, clojure authors typically make this pretty clear
16:22	Chousuke	hmm, well, you can use ! in naming :)
16:22	Chousuke	haphazardly mixing functional things and size effects just leads to bad code so it's implicitly discouraged :P
16:24	{aaron}	i see, that's what i was looking for
16:24	_ato	yep, usually it's either fairly clear from the context (eg you're doing IO or talking to a SQL database or something) or the ! naming convention is used.
16:25	{aaron}	cool
16:25	Chousuke	I think clojure actively tries to support a functional programming style rather than discourage any other style.
16:26	Chousuke	but a natural consequence is that imperative programming in clojure tends to feel out-of-place :/
16:26	qbg	When using lein swank, the system classloader doesn't have the project on the classpath, so where can I find a classloader that does?
16:27	Chousuke	hmm, wasn't there some function to get Clojure's classloader? :/
16:28	_ato	(clojure.lang.RT/baseLoader) IIRC
16:32	qbg	Yep, that works
17:30	technomancy	just tagged a Leiningen 1.1.0 release candidate: http://github.com/technomancy/leiningen/blob/master/NEWS
17:31	technomancy	would love to get some more eyes on it before the release
17:31	qed	technomancy: grabbing it right now
17:31	qed	thanks! :)
18:29	AWizzArd	rhickey: Is there a principle possibility to make insertion into sorted-sets (or maps) faster? Something like "transient sorted-sets" into which I insert elements guaranteed in the correct order?
18:30	AWizzArd	,(let [x (range 300000)] (count x) (time (count (apply sorted-set-by < x))))
18:30	clojurebot	300000
18:30	clojurebot	"Elapsed time: 7320.944 msecs"
18:30	AWizzArd	,(let [x (range 300000)] (count x) (time (count (apply vector x))))
18:30	clojurebot	300000
18:30	clojurebot	"Elapsed time: 92.089 msecs"
18:33	chouser	,(let [x (range 300000)] (count x) (time (count (into [] x))))
18:34	chouser	,(let [x (range 300000)] (count x) (time (count (into [] x))))
18:34	clojurebot	300000
18:34	clojurebot	"Elapsed time: 163.705 msecs"
18:34	chouser	,(let [x (range 300000)] (count x) (time (count (into [] x))))
18:34	clojurebot	300000
18:34	clojurebot	"Elapsed time: 132.526 msecs"
18:35	chouser	,(let [x (range 300000)] (count x) (time (count (vec x))))
18:35	clojurebot	300000
18:35	clojurebot	"Elapsed time: 86.965 msecs"
18:35	AWizzArd	also interesting
18:35	AWizzArd	vec and vector use transients under the hood i guess
18:35	hiredman	I doubt it
18:36	hiredman	I imagine they use to-array under the hood
18:46	mecolin	hello
18:46	chouser	hi
18:47	mecolin	i have these two snippets http://pastie.org/803512
18:47	mecolin	how can i make the second snippet to evaluate in the first one ?
18:49	Raynes	There are a couple of pastebins that do Clojure highlighting specifically, including gist.github.com, paste.pocoo.org, ideone.com (also evaluates your code for you), and I think snipt.org does as well.
18:49	Raynes	Not that it matters all that much. Just sayin'. :)
18:49	chouser	what's read-file? but perhaps that doesn't matter -- you were hoping for the locals 'meta' and 'content' to be available to the code you're eval'ing?
18:49	mecolin	Raynes: thanks ;)
18:50	mecolin	chouser: I'd like to start off with snippet 2 to evalute in place of (eval tempalte)
18:51	chouser	have you tried 'load-file'?
18:52	mecolin	chouser: next, I'd like decorate it with content and meta data
18:52	mecolin	chouser: with 'load-file' i cannot achieve it, can i ?
18:52	chouser	correct, you cannot.
18:52	chouser	nor with eval the way you're going about it.
18:53	mecolin	can you give some clue how should i proceed ?
18:53	mecolin	s/give/give me
18:53	chouser	I think you'd have to read in the file and wrap it in (let [...] ...), then eval that let form.
18:53	chouser	,(eval (read-string "(+ 10 foo)"))
18:53	clojurebot	DENIED
18:54	chouser	bah. anyway, that fails because foo is undefined
18:54	mecolin	ok
18:54	chouser	but this fails the same way: (let [foo 5] (eval (read-string "(+ 10 foo)")))
18:55	chouser	this returns 15: (eval `(let [~'foo 5] ~(read-string "(+ 10 foo)")))
18:55	mecolin	chouser: thanks !
18:55	chouser	hm. you might have other problems though if the file you're reading in is doing 'ns' or 'in-ns'
18:56	mecolin	in fact, i'm doing it in the 2nd snippet
18:58	chouser	yes you are. trouble.
19:06	mecolin	chouser: if i defined a function in 2nd snippet (let's say: defn template), is there a way to switch different layouts in 1st snippet using :use but within render-template ?
20:09	qed	eeneeeeasd
20:14	ag90	Hi. Does the Class/StaticField form work for static enums?
20:16	ag90	I'm trying to access java.awt.TrayIcon.MessageType but it complains about not being able to find the class. I have improted (java.awt TrayIcon) but none of the following work:
20:16	ag90	TrayIcon/MessageType/INFO
20:16	ag90	TrayIcon.MessageType/INFO
20:18	arbscht	java.awt.TrayIcon$MessageType/INFO
20:18	ag90	Oh great that works.
20:18	ag90	Thanks
20:40	konr	Guys, why is this false?
20:40	konr	,(= "44" (reverse "44"))
20:40	clojurebot	false
20:40	hiredman	,(reverse "44")
20:40	clojurebot	(\4 \4)
20:41	hiredman	,(= "44" '(\4 \4))
20:41	clojurebot	false
20:41	hiredman	good?
20:41	konr	yes! thanks!
20:43	konr	the correct would be, then
20:43	konr	,(= "44" (reduce str (reverse "44")))
20:43	clojurebot	true
20:43	hiredman	apply str, not reduce
20:43	konr	Why?
20:43	clojurebot	why not?
20:43	hiredman	clojurebot: deep
20:43	clojurebot	It's greek to me.
20:44	hiredman	str uses a StringBuilder internally for multiple args (the apply case), the reduce case produces more intermediate garbage
20:49	ts00000	anyone here with some clojureql clue?
21:38	jcromartie	would it make any reasonable sense to use a set with vectors as keys for two-dimensional data?
21:39	jcromartie	sorry, hash-map, not set
21:40	jcromartie	,{[0,1] :foo [1,1] :bar}
21:40	clojurebot	{[0 1] :foo, [1 1] :bar}
21:40	jcromartie	it seems pretty natural
21:40	jcromartie	and it's sparse
22:16	chouser	jcromartie: sure, why not.
22:16	chouser	maybe a sorted-map, depending on how you intend to use it
23:23	mquander	i'd like to have a function that either takes a number n, a number n and a list of strings xs, and if i pass it a number n and a single string x, i'd like to treat that string as a list of one string
23:23	mquander	is there a nice way to do this?
23:24	mquander	oh nevermind
23:24	mquander	i figured out how to do it using apply
23:34	technomancy	given a var that's bound to a function and a list of arguments to apply, is there anyway to tell if the arity is correct by looking at the :arglists metadata?
23:34	technomancy	I mean a built-in function?
23:35	hiredman	,(:arglists (meta #'+))
23:35	clojurebot	([] [x] [x y] [x y & more])
23:35	technomancy	I guess it wouldn't be terribly hard to just figure it out with reduce
23:35	hiredman	,(map count (:arglists (meta #'+)))
23:35	clojurebot	(0 1 2 4)
23:35	hiredman	or something
23:36	technomancy	trickier to do with varargs though, which is why I'd like something built-in
23:37	hiredman	,(map #(if (.contains % '&) :vararg (count %)) (:arglists (meta #'+)))
23:37	clojurebot	(0 1 2 :vararg)
23:52	abrooks	I'm pretty sure that there's a way to type-hint a defn with its metadata but I'm failing to emit the right words into Google to find it.
23:52	abrooks	Oh, I want to type hint the type on the RETURN Value.
23:54	abrooks	Hm. I should looking core.clj...
23:55	abrooks	Ah... {:tag "[Ljava.lang.Object;"}