#clojure – 2009-10-12

2009-10-12

04:27	LauJensen	Morning gents
04:53	AWizzArd	Hi the Lau.
04:57	adityo	Totally n00b question..in clojure how will i comapre two strings? eg. "Clojure" and "clojure"?
04:59	hoeck	,(= "Clojure" "Clojure")
04:59	clojurebot	true
04:59	AWizzArd	adityo: http://java.sun.com/javase/6/docs/api/java/lang/String.html#equalsIgnoreCase%28java.lang.String%29
05:00	AWizzArd	,(.equalsIgnoreCase "cloJURE" "CLOjure")
05:00	clojurebot	true
05:00	hoeck	those were lower and uppercase C's in "clojure"?
05:01	adityo	yeah i dont want to Ignore case?
05:02	hoeck	adityo: then use =
05:03	adityo	okie..is it equivalent to java equals
05:04	hoeck	adityo: yes, = uses equals under the hood
05:07	hoeck	adityo: stated in the doc of =, try: (doc =)
05:08	adityo	hoeck: yes i did check it out, thanks :)
05:15	triyo	I have a string that contains 2 forms "(print (+ 2 1) (print (- 2 1))". The read function seems to be able to read the forms from the Reader however it seems to only grab the first form. Am I missing some iteration spec to get the next form from my string reader?
05:16	ambient	you're parentheses are unequal
05:16	ambient	*your
05:16	triyo	Sorry typo in this message
05:20	hoeck	triyo: are you using the read-string function?
05:20	triyo	,(-> "(print (+ 2 1)) (print (- 2 1))" java.io.StringReader. java.io.PushbackReader. read)
05:20	clojurebot	(print (+ 2 1))
05:20	triyo	Using read
05:20	triyo	As above
05:20	hoeck	triyo: read only reads one object at a time
05:21	hoeck	to read in the whole string, either wrap it into a seq by using iterate
05:22	triyo	Ok I'll try that
05:22	hoeck	or wrap the string in parens using (str "[" your-string "]") and read that
05:22	Chousuke	don't forget that read-string exists :)
05:23	hoeck	,(read-string "first second")
05:23	clojurebot	first
05:23	hoeck	,(read-string (str "[" "first second" "]"))
05:23	clojurebot	[first second]
05:26	triyo	Thx hoeck, that'll work for me.
07:12	ambient	anyone know of the fate of Counterclockwise (clojure eclipse plugin)?
07:12	ambient	where would i get the latest, seems that it only supports clojure 1.0.0 and i need to use a newer platform
07:12	ambient	~ccw
07:12	clojurebot	ccw is http://github.com/laurentpetit/ccw
07:15	ambient	not sure who maintains it and is it even actively developed
07:18	rsynnott	isn't there another eclipse plugin?
07:21	ambient	clojure-dev was the original, but it was renamed to counterclockwise
07:31	cgrand	ambient: Laurent Petit (lpetit here) is actually the main developer
07:45	AWizzArd	I have one agent A and many threads which do (send A foo). foo must not threadsafe. The queue of A helps to serialize my requests. Each thread does the (send A...) and then (await A), to get the result. But now the question is how I can (deref A) so that I will get the result which was produce for the current thread.
07:45	AWizzArd	What I currently do is (let [x (atom nil)] ... (send A foo x) (await A) and have foo writing its result to x, and then I can work with @x.
07:46	AWizzArd	foo must not threadsafe ==> foo is not threadsafe
07:47	AWizzArd	cgrand: is there something like await which also returns the result of the agent?
07:50	cgrand	AWizzArd: clojure 1.0 or 1.1?
07:50	AWizzArd	a fresh master
07:50	AWizzArd	so, 1.1 i would say
07:51	AWizzArd	my clojure-version ==> {:interim true, :major 1, :minor 1, :incremental 0, :qualifier "alpha"}
07:51	cgrand	good! you can use a promise instead of an atom, thus you'll don't have to await, just @my-promise (it will block)
07:52	cgrand	or get rid of agents and use futures with you own executor
07:52	AWizzArd	ah okay, never heard of promises before.. is there already a doc page set up?
07:52	cgrand	I dunno
07:52	AWizzArd	is the promise the replacement for the agent or the atom or their combination?
07:53	cgrand	promises are simple: (def p (promise)) to create, (deliver p value) to set, @p to block and get
07:54	cgrand	do you _really_ need to proces the returned value on the same thread that dispacthed the action to the agent?
07:55	AWizzArd	It is a thread which jetty/compojure opens and which handles the request.
07:55	cgrand	ok
07:55	AWizzArd	My processing function may run in parallel, and i want the result in the same thread, so i can generate a response.
07:56	AWizzArd	The await makes sure that the thread will wait for the (send ..) which I did just one line above, right? I can not accidently await that A returns from a different thread?
07:57	cgrand	await awaits that actions dispatched from the current thread are executed
07:58	AWizzArd	ok good
07:58	AWizzArd	and btw, what is the advantage of a promise over an atom?
07:58	cgrand	atom+await ~= promise (in your use case)
07:58	cgrand	no explicit await
07:58	AWizzArd	well, I have a agent+atom+await
07:59	cgrand	agent+atom+await ~= agent+promise :-)
07:59	AWizzArd	okay good, I will test that - sounds good
08:00	cgrand	(let [x (atom nil)] ... (send A foo x) (await A) (do-something @x)) becomes (let [x (promise)] ... (send A foo x) (do-something @x))
08:02	AWizzArd	yes, I am doing this now, thanks for this tip
08:02	AWizzArd	didn't know this promise thing
08:05	adityo	how to convert a string to a number for eg. "2" to 2
08:06	eevar2	(Integer/parseInt "2")
08:07	adityo	hey thanks eevar2
10:09	octe	has anyone used clojure-install to set up slime/swank/clojure recently?
10:09	octe	it seems it sets up the swank-clojure-jar-path variable, but the latest swank-clojure doesn't use it anymore..
10:28	ambient	is git integration in emacs ok+
10:28	ambient	or would it be better to use it from command line
10:29	ambient	(ok this was perhaps too off-topic)
10:30	liwp	ambient: AFAIK there is no git integration in emacs out of the box
10:30	liwp	ambient: there is magit, which apparently works ok, but I haven't tried it myself
10:30	noidi	http://zagadka.vm.bytemark.co.uk/magit/
10:31	liwp	noidi: have you used it?
10:31	noidi	I only installed it a few days ago so can't really comment on it yet
10:32	froog	there's a good magit introduction video here: http://www.vimeo.com/2871241
10:32	liwp	I've never used SCM tools from emacs. Some people seem to love the VC-mode integration though. AFAICT it works on a per file basis which seems a bit weird to me, i.e. my commits tend to span more than one file and I'd like those changes to show up as a single commit
10:32	liwp	but I've probably misunderstood something...
10:34	ambient	i'd rather use mercurial but git seems to be de facto standard for open source devs, and gaining momentum a lot faster :/
10:36	Raynes	Git is the chit.
11:02	durka42	anybody know why there is no clojure package for debian lenny?
11:04	LauJensen	durka42, debian :P
11:04	durka42	i suppose clojure is not considered "stable"
11:15	ambient	the same code works from command line "java clojure.main gears.clj" but not from emacs using C-c C-k :(
11:16	ambient	"could not locate penumbra/opengl__init.class or..."
11:16	LauJensen	ambient, which OS are you on?
11:16	ambient	vista
11:16	LauJensen	aha... and you say you're having problems.... :)
11:17	ambient	i dont have much choice in the matter
11:17	LauJensen	Is it still the LIBRARY_PATH tripping you up ?
11:17	ambient	i have no such thing defined in my env vars
11:18	LauJensen	we can talk in priv if u need help
11:28	chouser	huh, I didn't know this... http://www.cs.umd.edu/~pugh/java/memoryModel/DoubleCheckedLocking.html
11:28	octe	i have a vector containing vectors with 2 elements in each one.. i want to create a hash-map from this
11:28	octe	i'm not even sure where to start
11:29	chouser	octe: (apply into {} your-vector)
11:29	chouser	wait
11:29	chouser	,(into {} [[1 2] [3 4] [5 6]])
11:29	clojurebot	{1 2, 3 4, 5 6}
11:29	chouser	there you go -- no apply
11:30	octe	cool, now i'm just wondering what the , does :)
11:30	dreish	chouser: Not that I'm endorsing double-checked locking, but the first objection they raise doesn't apply if all fields are final.
11:30	noidi	chouser, cool! :)
11:31	dreish	You can never see a "pre-initialized" value of a final field.
11:31	noidi	I ended up with: (into {} (map #(apply hash-map %) [[:foo 1] [:bar 2]]))
11:31	noidi	plenty of clojure idioms to learn :P
11:31	chouser	octe: , is whitespace in clojure -- , in IRC tells clojurebot to do it.
11:31	octe	oh..
11:31	octe	i thought it meant something special
11:31	chouser	just here
11:31	chouser	,(+ 1 2)
11:31	clojurebot	3
11:33	noidi	,(conj {} [[:foo :bar] [:baz :blah]])
11:33	clojurebot	{[:foo :bar] [:baz :blah]}
11:33	noidi	wow, I didn't know that conj is so flexible
11:33	noidi	,(conj {} [:foo :bar])
11:33	clojurebot	{:foo :bar}
11:33	noidi	eh, it wasn't :)
11:34	chouser	noidi: you understand your first example made a vector key?
11:34	noidi	yeah, i see it now
11:34	chouser	,(apply conj {} [[:foo :bar] [:baz :blah]])
11:34	clojurebot	{:baz :blah, :foo :bar}
11:34	chouser	but don't do that. Use into.
11:36	chouser	This surprises me a bit:
11:36	chouser	,(conj {} {:a 1, :b 2} {:c 3, :d 4})
11:36	clojurebot	{:d 4, :c 3, :b 2, :a 1}
11:38	octe	http://pastebin.ca/1615642 <- so this is a good way to do what i want? (parse line with fields seperated by ":" and their key/value seperated by "=" and turn it into a map)
11:38	froog	,(into {} [[1 2] [3 4] [5 6]])
11:38	clojurebot	{1 2, 3 4, 5 6}
11:39	froog	what version is clojurebot running?
11:39	froog	I get: {5 6, 3 4, 1 2}
11:40	chouser	froog: map order isn't generally guaranteed, so it shouldn't matter to you which you get. I happen to get the same as clojurebot on latest master.
11:42	chouser	octe: yep, looks good. you might want to take advantage of #() and the more modern (.method obj arg) interop form
11:43	chouser	dreish: as it mentions, though, there are more and more reasons it doesn't work. for example is the pointer assignment atomic?
11:43	durka42	is pastebin.ca dead or is it just me?
11:44	dreish	Like I said, I'm not claiming double-checked locking is okay.
11:44	froog	chouser: that makes sense. Still, would've expected the output to have been the same
11:44	octe	chouser: thanks
11:45	chouser	froog: yeah, I'm surprised by your output. what version are you running? :-)
11:45	octe	#().. more magic ungoogable symbols ;) (found the docs on clojure.org though)
11:45	froog	chouser: "1.0.0--SNAPSHOT"
11:45	froog	,(clojure-version)
11:45	clojurebot	"1.1.0-alpha-SNAPSHOT"
11:47	chouser	octe: and even more: ->> can be used here (though not sure if it's better than without it)
11:47	chouser	that's not even on clojure.org yet. :-/
11:48	chouser	,(let [line "version=123:foo=bar:something=moo"] (->> (.split line ":") (map #(vec (.split % "="))) (into {})))
11:48	clojurebot	{"version" "123", "foo" "bar", "something" "moo"}
11:56	froog	is 1.1.0 going to be a bugfix release?
11:57	morphling	hi, is there a way to get the argument count of a #(...)-created function?
11:58	morphling	I found (count (first ((meta #'foo) :arglists))), but that does not seem work on anonymous functions created by #() or (fn)
12:00	technomancy	cgrand: party time!
12:02	cgrand	morphling: no, you can't get the argcount of a function. What are you trying to do?
12:03	djork	I'm using Aquamacs and it seems like clojure-install from clojure-mode fails to "stick"
12:03	djork	not sure why
12:03	technomancy	djork: did you follow the note at the end of the install process?
12:03	djork	I think so
12:03	djork	(can't remember)
12:04	morphling	cgrand: I'm trying to print a truth table for a boolean function, it would be nice you did not have to specify the argcount explicitly
12:05	chouser	froog: depends on what you mean I guess -- lots of new features coming.
12:06	chouser	morphling: you can introspect on the invoke methods of the class created, but it's definitely a hack
12:08	cgrand	other hack: try to call the function and catch the exception when you call with an unsupported argcount
12:08	djork	technomancy: yup, I missed it :)
12:08	djork	that was easy
12:09	djork	<3 swank-clojure and clojure-mode... now that it works every time :D
12:10	morphling	I actually thought of the latter but it's not worth the hacks
12:10	noidi	,(doc partial)
12:10	clojurebot	"([f arg1] [f arg1 arg2] [f arg1 arg2 arg3] [f arg1 arg2 arg3 & more]); Takes a function f and fewer than the normal arguments to f, and returns a fn that takes a variable number of additional args. When called, the returned function calls f with args + additional args."
12:10	noidi	morphling, maybe that could work for you?
12:11	noidi	,((partial str "foo") "bar" "baz")
12:11	clojurebot	"foobarbaz"
12:12	noidi	oops, i didn't even understand the question properly
12:12	noidi	maybe i'll just shut up and call it a day :)
12:25	technomancy	djork: most of the problems people have are missing that notice... I think I might automate the process of adding it to your config.
12:25	djork	it should just be on a separate line, like the "run M-x slime" line
13:03	froog	,(into {} [[:a 1] [:b 2] [:a 43]])
13:03	clojurebot	{:a 43, :b 2}
13:37	raek	how do I do the dissoc counterpart to assoc-in ?
13:38	raek	nevermind, found clojure.contrib.core/dissoc-in
13:42	ambient	so, did anyone at any point complete the translation of Minilight (ray tracing engine) to Clojure?
13:42	ambient	there seem to have been several attempts
13:44	djork	hmm, it appears that Clojure is not suited to serving up dumb cgi scripts :)
13:45	djork	(s/Clojure/Java)
13:47	drewr	not if you'd like to exceed >1 req/s
13:57	funkenblatt	yeah... wouldn't that have to restart the jvm process every time?
14:04	drewr	funkenblatt: yep
14:06	chouser	you at least need fastcgi or equiv, and it's hard to find a context where that's a better fit than jetty or some other servlet container.
14:07	LauJensen	funkenblatt, if your only problem is start/stopping the JVM, just use Nailgun
14:07	funkenblatt	heh... not MY problem per se
14:07	funkenblatt	but i'll keep that in mind
14:07	drewr	do you guys know if there is a fs-backed version of LinkedBlockingQueue?
14:08	drewr	thinking about writing one, but not sure if it's solving the right problem
14:09	drewr	I need somewhere to stash data while I process it, but I don't want the heap to fill up
14:09	licoresse	...
14:11	chouser	drewr: seems pretty reasonable. I think several message-passing libs provide disk buffering
14:11	chouser	except I'm probably using all the wrong terminology because I still don't know anything about them. :-)
14:11	drewr	yeah, looks like jms et al have similar func
14:12	drewr	wanted something lighter weight than that, but it's not a trivial solution
14:24	raek	I am amazed how simple it is to make a simple event-driven system!
14:24	raek	http://gist.github.com/208575
14:25	technomancy	drewr: rabbitmq is great at that.
14:25	raek	clojure is the only language I've been using where my code actually shrinks in size the more I work on it
14:25	Chousuke	heh
14:25	raek	now: begin coding on irc bot
14:25	Chousuke	hack on Clojurebot :P
14:26	technomancy	clojurebot's nontrivial to set up and hack on. =\
14:26	chouser	raek: that's pretty tidy. I love how all of the code (except the example usage) could be used as-is on any reference type, not just an agent.
14:28	djork	"how simple it is to make a simple ..."
14:28	djork	it always is :)
14:28	chouser	raek: depending on how you intend to use it, you might also consider multimethods instead.
14:28	djork	now make a complex one :P
14:29	raek	chouser: in what way?
14:29	raek	I want to be able to have multiple event handlers
14:30	drewr	technomancy: yeah, we're already using that in our infrastructure, although I wanted to solve this problem inside one jvm
14:31	drewr	raek: clot has the beginnings of what you want
14:31	hiredman	technomancy: :(
14:32	hiredman	clojurebot: be simpler
14:32	clojurebot	It's greek to me.
14:32	technomancy	hiredman: well, at the time I tried it, fnparse was totally nonfunctional.
14:32	hiredman	yeah
14:33	technomancy	probably has improved since then
14:33	hiredman	I have had thought perhaps hitching clojurebot's star to fnparse's wagon was not the wisest move
14:33	technomancy	still though, until you get the deps situation improved, recommending it for a newbie to hack on is questionable
14:33	hiredman	yes
14:38	chouser	raek: ah, good point -- multimethods are probably not a good fit then.
14:43	adityo	can anybody provide an example of using sort-by with an comparator?
14:46	adityo	ping
14:46	Chousuke	hm
14:47	Chousuke	,(sort-by count > [[1] [1 2] [1 2 3]])
14:47	clojurebot	([1 2 3] [1 2] [1])
14:47	Chousuke	like this?
14:48	adityo	yeah, sort-by by default returns in an ascending order
14:49	Chousuke	the docstring is pretty clear
14:50	LauJensen	Speaking of clear, is there some work being put into those backtraces?
14:50	adityo	yep, it is
15:53	ambient	how do i know after which operations i can still use the function lazily?
15:53	ambient	for example, does into-array break the laziness?
15:54	chouser	into-array is greedy
15:54	chouser	I think everything lazy says it is.
15:55	ambient	eg. range doesn't say it is lazy, nor does map
15:59	Chousuke	,(doc map)
15:59	clojurebot	"([f coll] [f c1 c2] [f c1 c2 c3] [f c1 c2 c3 & colls]); Returns a lazy sequence consisting of the result of applying f to the set of first items of each coll, followed by applying f to the set of second items in each coll, until any one of the colls is exhausted. Any remaining items in other colls are ignored. Function f should accept number-of-colls arguments."
15:59	ambient	i can define oscillators as infinite sequences :))
15:59	Chousuke	third word. :P
15:59	ambient	hmm, ok i see
16:08	hiredman	if the sequence interface allows it to be lazy, it is
16:08	ambient	(audiochan-play source (into-array Byte/TYPE (take (msec-samples 500) (sin-osc 440.0)))) this works
16:10	ambient	i'll see if i can do the whole synth framework lazily
16:10	ambient	IIR filters might be a PITA thou
16:13	funkenblatt	there's a recursive sequence thing in clojure-contrib
16:13	funkenblatt	that'll do IIR filters
16:13	ambient	sweet
16:16	adityo	how do i remove all nil's in '(1 nil 3 nil 6 nil nil)
16:17	funkenblatt	,(filter identity '(1 nil 3 nil 6 nil nil))
16:17	clojurebot	(1 3 6)
16:17	adityo	.(doc identity)
16:17	Chousuke	identity does nothing :)
16:17	adityo	,(doc identity)
16:17	clojurebot	"([x]); Returns its argument."
16:18	Chousuke	a better way would be (remove nil? ...)
16:20	adityo	thanks :Chousuke :funkenblatt
16:26	arohner	Chouser: I asked this question the other day, but I don't think you were around
16:27	arohner	in Clojurescript, how do you determine whether a form is a javascript memeber access vs. function call?
16:27	arohner	i.e. (. foo bar) turns into "foo.bar()" or "foo.bar"?
16:28	Chousuke	is clojurescript actually functional? :/
16:30	raek	,(into {} '([:a 1] nil [:b 1] nil))
16:30	clojurebot	{:a 1, :b 1}
16:34	arohner	Chousuke: sort of
16:34	arohner	I'm asking because I'm trying to figure out how to handle it in scriptjure
16:34	arohner	and javascript cares about the difference between foo.bar and foo.bar()
16:35	Chousuke	does it have static fields like java though?
16:35	arohner	what do you mean by static?
16:36	Chousuke	I mean, if javascript doesn't need it, maybe you could use the Foo/bar notation to differentiate
16:36	arohner	yeah, but so far scriptjure's semantics are largely the same as clojure's
16:37	arohner	Foo/bar in clojure can be a variable access or a function call
16:37	arohner	which it can do because it can know the type of bar
16:38	arohner	if I want to do that, I have to add a check in the generated code
16:38	Chousuke	hmmh :/
16:39	Chousuke	the conceptually valid choice would be to require users to write ((.foo bar) args) but that's not very neat
16:39	arohner	right
16:43	arohner	the other thing that's interesting is that in javascript, foo.bar could be a function, so you could want to return the function. you can't do that in Clojure, so that's something else I have to worry about
16:45	Chousuke	hm
16:46	lpetit	,clojure-version
16:46	clojurebot	{:interim true, :major 1, :minor 1, :incremental 0, :qualifier "alpha"}
16:46	Chousuke	I really can't think of any other way than restricting (.foo bar) to be field access only
17:49	itistoday	is it possible to create lexical closure with 'with-local-vars'?
17:49	itistoday	i.e., I'm trying to see if it's possible to avoid using atoms to create a counter-generator. no practical reason, just an exercise
17:49	itistoday	this is what i have so far:
17:49	itistoday	(defn new-counter [] (with-local-vars [a 0] (fn [] (var-set a (inc @a)))))
17:49	itistoday	and it doesn't work
17:51	itistoday	yes, i know that code is probably in terrible form ;-)
17:56	ambient	is there a way to polymorphically handle sequences and numbers (floats, integers, etc..)? like (* 10.0 (repeat 5.0))
17:57	ambient	vectors and matrices wouldbe gravy
18:05	morphling	ambient: (map (partial * 10.0) (repeat 5.0)) ?
18:05	ambient	the point is that i dont want to use map
18:06	ambient	because im using map on every damn line :/
18:06	ambient	if * / + - would be polymorphic, my code size would dramatically lessen
18:06	morphling	ah
18:06	ambient	and all basic functions that work on one numeric input
18:06	ambient	like sin, cos etc
18:07	ambient	perhaps i should write equivalent macroes that just wrap all numbers to (repeat foo)
18:10	ambient	simple frequency modulation looks like this: (take 15000 (sin-osc (map + (repeat 440.0) (sin-osc (repeat 100.0)))
18:11	ambient	when it could be (sin-osc (+ 440.0 (sin-osc 100.0)))
18:16	itistoday	is it possible to create lexical closure with 'with-local-vars'?
18:17	itistoday	i.e., I'm trying to see if it's possible to avoid using atoms to create a counter-generator. no practical reason, just an exercise
18:17	itistoday	this is what i have so far:
18:17	itistoday	(defn new-counter [] (with-local-vars [a 0] (fn [] (var-set a (inc @a)))))
18:17	itistoday	it doesn't work though (java.lang.IllegalStateException: Var null/null is unbound.). Yes, I also know that it's probably in bad for, but i was just wondering if it was possible
18:18	itistoday	it could be thread-safe though if the function were only used in a single thread :-)
18:19	Licenser_	itistoday: everyting is thread safe when only used in a single thread :P
18:20	itistoday	Licenser_: indeed, and that's kinda an interesting point, because Clojure doesn't seem to offer optimizations for that case...
18:20	Licenser_	I know, but it
18:20	Licenser_	I know, but it's a tradeoff for the fact that we get thread safety for most of everything for no extra work ;)
18:22	itistoday	it would be cool though if you could bind a function, or an "instance" of a function to a specific thread. that would be a neat optimization, and a sort-of "best of both worlds" approach i think
18:22	itistoday	but i have a feeling that the mindset of clojure is "we don't want you shooting yourself in the foot accidentally"...
18:23	itistoday	it might be possible to ensure thread-safety though. sortof how you can't use set! except in (binding ..)
18:23	technomancy	you can use alter-var-root outside of binding, but it's almost always the Wrong Thing to Do.
18:24	itistoday	technomancy: thanks, didn't know of that function
18:24	itistoday	why then are there atoms?
18:24	danlarkin	unless you're using with-alter-var-root!!!
18:25	itistoday	that's another thing i'm having difficulty understanding, is the point of atoms
18:25	itistoday	or perhaps the point of vars.
18:25	itistoday	(i.e. use atoms everywhere instead of vars)
18:27	gbj	i love with-alter-var-root!!
18:27	danlarkin	gbj: you would!
18:27	itistoday	what is the reasoning to have atoms and vars as opposed to just one of them?
18:28	danlarkin	itistoday: vars are threadlocal
18:28	itistoday	danlarkin: what about vars bound to the root?
18:28	itistoday	with def?
18:29	itistoday	are they threadlocal?
18:29	kib2	Hi; is there any way to repeat a string a given times ?
18:30	itistoday	quiet day?
18:31	danlarkin	well it's more nuanced than vars just being threadlocal
18:31	itistoday	kib2: (repeat 4 "foo") ?
18:31	danlarkin	bindings are thread local
18:31	itistoday	sure, bindings are threadlocal, but does that make vars threadlocal? i don't think they are
18:32	kib2	itistoday: so simple! I was looking for java solutions! thanks.
18:32	itistoday	and as technomancy pointed out, you have alter-var-root
18:32	itistoday	which seems very similar to set!
18:32	itistoday	rhickey: taskete! save me!
18:33	technomancy	dude.
18:33	technomancy	no offense, but I think Rich has more important things to do than explain this to you.
18:33	danlarkin	+1
18:33	itistoday	technomancy: probably, couldn't hurt to ask though?
18:34	itistoday	if he didn't want to be bugged would he be on this channel?
18:34	itistoday	:-)
18:35	chouser	vars are what namespaces intern
18:35	danlarkin	every time rich answers a question in IRC he's not accepting technomancy's patches :)
18:35	chouser	hehe
18:36	itistoday	chouser: i guess i'm asking, why have vars and atoms? why not just have one of them? and aren't symbols interned, not vars?
18:37	chouser	itistoday: symbols are not interned
18:38	itistoday	chouser: i'm reading through clojure.org/vars and i don't quite get it
18:38	chouser	itistoday: a namespace holds a bunch of named vars because that provides useful semantics for named globals with optional thread-local dynamic scope
18:39	chouser	atoms provide no thread-local or dynamic scope, but use fast CAS to make changes to the value they store.
18:40	itistoday	chouser: and they are also not named...?
18:40	itistoday	and by that meaning they are not "interned"?
18:40	chouser	that's true, though the fact that vars know their own name (if any) may be more of an implementation detail.
18:41	octe	is there a repository for clojurebot's code?
18:41	itistoday	chouser: i suppose being more anonymous does give them a unique use
18:42	itistoday	chouser: and the fact that vars, unlike atoms, can be used with 'with-local-vars'
18:42	chouser	itistoday: interned I think in this case means that there is a single place for each named var -- if you do (def foo) two different times in the same namespace, there will still be only the one var
18:42	chouser	with-local-vars is how you can create anonymous vars -- an extremely rarely used feature afaik
18:43	itistoday	ahhhh, so both atoms and vars can be anonymous
18:43	itistoday	but vars... unlike atoms, can be "non-anonymous"... eh...
18:43	itistoday	my head hurts
18:43	itistoday	i guess the main thing is that atoms are always global
18:43	itistoday	or rather, always "shared data" CAS stuff
18:44	itistoday	and vars are less likely to be mutated
18:44	itistoday	and can be local
18:44	itistoday	chouser: get-var/set-var do not use CAS, correct?
18:44	chouser	itistoday: correct -- I believe they use a lock on the var
18:45	itistoday	a lock??
18:45	technomancy	itistoday: clojure existed for quite some time without atoms... if you're just getting started it would probably be easier to just ignore them and focus on refs and functional code first.
18:45	chouser	,(.sym (var print-length))
18:45	clojurebot	print-length
18:45	chouser	,(with-local-vars [x 5] (.sym x))
18:45	clojurebot	nil
18:45	itistoday	neat
18:45	itistoday	chouser: are you sure they use a lock?
18:45	chouser	itistoday: so there is a named vs. an anonymous var
18:45	itistoday	why would they use a lock?
18:46	chouser	itistoday: just for you, I'll check.
18:47	danlarkin	itistoday: clojure itself has lots of locks. The point is that it has them so you don't have to
18:47	itistoday	chouser: sorry, you don't need to trouble yourself for me
18:47	itistoday	chouser: but if you do i'm thankful!
18:47	danlarkin	well let me rephrase that... not "lots of locks", but it uses locking
18:47	chouser	itistoday: var-set is thread local, so there are no locks or anything there.
18:48	itistoday	chouser: that's what i thought, which is why i was shocked when you said it
18:48	chouser	itistoday: alter-var-root is a sychronized function, so it's essentially a lock.
18:48	itistoday	chouser: that's also good to know... although i think someone said it was CAS
18:48	chouser	atom is CAS
18:49	chouser	if it helps, here's how I think of them...
18:49	chouser	vars are how you build up the global definition of your program, but using them to store functions and configuration type values in namespaces.
18:50	chouser	on rare occasions it's useful to give a particular var a thread-local binding, perhaps to tweak the definition of a function or adjust one of those config values
18:51	chouser	they can be used in other ways, but it's hardly ever a good idea
18:51	chouser	I would not recommend storing any of your applications actual state in a var, for example.
18:52	chouser	atoms on the other hand are the very simplest way to store application data
18:52	itistoday	instead store it in an atom? or a ref?
18:52	chouser	right, or an agent
18:52	itistoday	gotcha
18:53	ambient	anyone know how i could make this into an actual infinite sequence? http://paste.pocoo.org/show/144606/
18:53	ambient	seems that (iterate inc 0.0) can't be infinite
18:53	ambient	at least performance wise
18:53	chouser	although both atoms and vars overlap in a subset of their technical feature support, I've never had any trouble choosing between the two for any particular purpose.
18:54	itistoday	chouser: thanks, that helps a bit
18:55	chouser	ambient: few things have infinite performance
18:55	chouser	:-)
18:55	chouser	sorry, I guess I don't know what you're asking.
18:55	ambient	what i meant that eventually it will jump into bignums and the program will DIE
18:55	chouser	ah
18:55	itistoday	chouser: the other day Chousuke helped me with a function i was trying to write, here it is: (defn new-counter [] (let [a (atom 0)] (fn [] (swap! a inc))))
18:56	ambient	because oscillators are by definition looping inside a defined waveform, im just trying to find out how to do an infinite stream of sin oscillator
18:56	ambient	which can be modulated by frequency
18:56	itistoday	chouser: (defn c (new-counter)) (c) => 1 (c) => 2, etc. Is there a way to do that instead with with-local-vars or is that not possible?
18:56	itistoday	chouser: i.e. i tried this and it failed: (defn new-counter [] (with-local-vars [a 0] (fn [] (var-set a (inc @a)))))
18:57	chouser	itistoday: right, vars aren't for that.
18:57	ambient	perhaps i should give up this stream based approach and just start managing global state :\|
18:57	chouser	ambient: wait wait
18:57	chouser	:-)
18:57	itistoday	chouser: k, thanks!
18:58	chouser	ambient: could you use bignum for all of them?
18:59	ambient	i'd rather not use bignum anywhere, because afaik it kills performance
19:00	ambient	here's the full app. im not sure my approach is the right one http://paste.pocoo.org/show/144608/
19:00	chouser	well, at some point your float is going be out of precision such that adding 1 to it wouldn't produce any different number if it were still a float.
19:00	chouser	what would you like it to do at that point?
19:01	ambient	i just want to loop between 0 and PI * 2
19:01	ambient	but twisting my brain around how to do that with streams, especially with phase and frequency modulation is just too much
19:02	itistoday	ambient: what does the function (or macro) 'do' do? i couldn't find it in the api
19:02	itistoday	(looking at your paste)
19:03	ambient	it does, sequentially
19:03	ambient	:p
19:03	itistoday	,(doc do)
19:03	clojurebot	Pardon?
19:03	itistoday	why isn't it in the API?
19:03	chouser	itistoday: do is a special operator, like if
19:04	itistoday	chouser: ah, ok. hopefully i'll stumble upon an explanation on the clojure site
19:05	itistoday	found it: http://clojure.org/special_forms
19:05	chouser	itistoday: http://clojure.org/special_forms#do
19:05	chouser	:-)
19:05	itistoday	hehe :-)
19:05	itistoday	it's like prgn?
19:05	itistoday	(or 'begin' in other languages)
19:05	chouser	ambient: do you need to be able to change the frequency during the course of the oscillation?
19:05	ambient	chouser yes
19:07	itistoday	ambient: sorry to bother, but if 'do' is like begin/prgn, why do you use it in audiochan-close/audiochan-play? doesn't defn allow you to not use it?
19:07	ambient	itistoday yes, probably
19:07	itistoday	ambient: ah k, just wondering, guess it's a matter of style
19:08	ambient	nah, it's completely redundant
19:08	itistoday	i wasn't going to say it ;-)
19:08	ambient	you're not clearly finnish
19:08	itistoday	:)
19:14	ambient	i think there's no going around it, oscillator has to have state
19:14	chouser	ambient: how will state help?
19:14	ambient	it will define at which point the oscillation is
19:14	ambient	which can then be phase modulated, and checked against limits
19:14	chouser	ambient: personally, I'd try bignum first since it's so easy. if the performance is unacceptiable, then take another look.
19:17	ambient	with state i can just do new_phase = (old_phase++)%256 in some old arcaic language, which keeps the oscillation inside 0..255
19:17	ambient	oops ++old_phase
19:18	ambient	immutability has corrupted my mind. it's phase = (++phase) % 256 of course
19:18	chouser	ah, that kind of "state" isn't so bad -- you can still use that to produce a lazy seq and therefore remain purely functional.
19:19	ambient	hmm i dont know how
19:19	chouser	seq-utils/reductions is one way to produce a lazy seq where each new value depends on the previous value.
19:19	ambient	because i have to modulate the phase delta
19:19	ambient	ok i'll check that out
19:19	chouser	but in this case it's probably easiest to use the lazy-seq macro directly
19:20	chouser	I hope lazy sequences themselves aren't too slow for your application.
19:20	ambient	yeah, we'll see
19:21	itistoday	what happened to lazy-cons?
19:21	chouser	itistoday: gone the way of all dinosaurs
19:21	funkenblatt	sleeping with the garbage collected fishes
19:21	itistoday	is lazy-seq its replacement?
19:21	chouser	ambient: have you used lazy-seq directly?
19:21	ambient	i think once, a month ago
19:22	ambient	:p
19:22	chouser	itistoday: http://clojure.org/lazy ...except what is future there is now past
19:22	itistoday	chouser: thanks
19:23	chouser	ambient: one technique would be to write your function as a infinitely recursive loop
19:23	ambient	yeah i was thinking about that too
19:23	chouser	(defn foo [i] (prn i) (foo (inc i)))
19:24	chouser	...that prints your new values.
19:24	chouser	then you can transform that into a lazy seq
19:24	chouser	(defn foo [i] (lazy-seq (cons i (foo (inc i))))))))) ; lost track of parens
19:25	itistoday	ambient: is your code somewhere? i'd love to see the finished version when it's ready
19:25	itistoday	ambient: just tried, sounded cool
19:26	ambient	well all the synth code is in the paste
19:26	itistoday	ambient: just wondering if you had it up, i.e. github or something like that
19:27	ambient	its on bitbucket but i'd rather not yet publish it anywhere
19:27	itistoday	mmk
19:31	chouser	Audio Device Unavailable ...my java audio setup must be completely broken and I just hadn't noticed before.
19:31	ambient	there might be some type hints missing
19:31	ambient	i stopped debugging when mine started working
20:08	octe	i've been reading up on concurrency-stuff in clojure and i'm kind of understanding how to deal with concurrent access to data objects, but what about sharing non-data non-threadsafe objects, like an OutputStream?
20:12	chouser	well, you've got to be careful. :-/ Often one nice way to handle an output stream use an agent to control access to it, so threads can send-off write functions to it.
20:14	octe	ok, i was thinking about agents but i wasn't sure that it "fit"
20:14	octe	i'll try it
20:16	itistoday	in http://clojure.org/lazy, why does he say use 'rest' instead of 'next' here: (lazy-cons (f (first coll)) (map f (rest coll)))))
20:17	itistoday	all that's said is "if consuming another seq, use rest instead of next", no clear explanation given
20:18	itistoday	err, rather, i copied the wrong code (from the old way)
20:18	itistoday	this is the one i'm referring to: http://paste.pocoo.org/show/144619/
20:18	itistoday	(copied from "The new way")
20:20	rhickey_	itistoday: using next would make it eager by one
20:20	chouser	next never returns an empty collection, but nil instead. This can be handy, but it means the next step of the lazy seq is forced so sometimes it's inappropriate
20:22	itistoday	does not compute
20:22	itistoday	sorry :-(
20:23	itistoday	i'm trying to understand this in terms of cons
20:23	itistoday	or rather... one sec
20:23	rhickey_	itistoday: it's not about the cons, but the args to cons, you'd be forcing the second arg (if it was lazy) by using next
20:24	rhickey_	(next x ) === (seq (rest x))
20:25	itistoday	do i understand correctly...
20:25	itistoday	rest returns a delay
20:25	itistoday	and next does not?
20:25	itistoday	or rather, next forces the delay returned by rest?
20:26	octe	chouser: i guess another alternative is to use something like a shared threadsafe queue object?
20:26	octe	that something reads off and sends off on the OutputStream..
20:26	chouser	octe: yes, that can work well. a BlockingQueue perhaps.
20:31	chouser	itistoday: a delay is something else specific. but if x is (cons a (lazy-seq ...)) then (rest x) doesn't force the lazy-seq while (next x) does.
20:33	itistoday	chouser: thanks, i think that helps a bit
20:33	itistoday	i'm playing around with the repl, hopefully that'll help clear up my confusion
20:33	itistoday	i think the problem is that i'm thinking in terms of streams
20:33	itistoday	what does lazy-seq do?
20:34	itistoday	nm.. reading the docs...
20:35	itistoday	,(doc first)
20:35	clojurebot	"([coll]); Returns the first item in the collection. Calls seq on its argument. If coll is nil, returns nil."
20:35	itistoday	,(doc next)
20:35	clojurebot	"([coll]); Returns a seq of the items after the first. Calls seq on its argument. If there are no more items, returns nil."
20:36	itistoday	,(doc rest)
20:36	clojurebot	"([coll]); Returns a possibly empty seq of the items after the first. Calls seq on its argument."
20:37	itistoday	,(doc seq)
20:37	clojurebot	"([coll]); Returns a seq on the collection. If the collection is empty, returns nil. (seq nil) returns nil. seq also works on Strings, native Java arrays (of reference types) and any objects that implement Iterable."
20:38	ambient	how do i generate infinite seq of random numbers? (take 10 (repeat (rand))) print out just one number for each run
20:39	chouser	repeatedly
20:39	funkenblatt	,(take 5 (map rand (repeat 1)))
20:39	clojurebot	(0.7265724927209442 0.3998850009265046 0.008882990808162017 0.1862657057261602 0.2660922579606133)
20:40	funkenblatt	there's probably a better way than that, but that's what came immediately to mind
20:41	ambient	(take 10 (repeatedly rand)) seems to work :)
20:41	itistoday	,(take 10 (repeatedly rand))
20:41	clojurebot	(0.7418891709881609 0.5002349453871904 0.6923304956080272 0.23683099175381928 0.6196438692623625 0.5261268340502978 0.4262760865021553 0.1628545274801868 0.8089272143742726 0.9269205296576724)
20:41	funkenblatt	oh standard libraries
20:42	funkenblatt	coming from scheme i'm totally used to not having any
20:43	itistoday	(defn rand-seq [] (lazy-seq (cons (rand) (rand-seq))))
20:43	itistoday	that works too
20:45	ambient	i'm wondering if i can keep a short ring-buffer inside a lazy-sequence
20:45	tomoj	itistoday: that's exactly what repeatedly does :)
20:45	ambient	loop/recur can be used to maintain some sort of state but dont know if it works with lazy-seq
20:46	chouser	you want something other that 'cycle' I guess?
20:46	itistoday	chouser: check this out:
20:46	itistoday	,(rest (cons 1 (lazy-seq (println "foo"))))
20:46	clojurebot	()
20:46	itistoday	,(next (cons 1 (lazy-seq (println "foo"))))
20:46	clojurebot	foo
20:46	chouser	ring-buffer sounds mutable -- not a good idea for a lazy seq
20:47	itistoday	illustrating your point right?
20:47	itistoday	,(seq (rest (cons 1 (lazy-seq (println "foo")))))
20:47	clojurebot	foo
20:47	ambient	chouser perhaps ring-buffer is not the right term, values that depend on the previous values
20:47	ambient	and roll-around depending on conditions
20:47	chouser	ambient: yeah, you can do that with lazy-seq
20:47	hiredman	you can implement a ring buffer with a vector and an index to the currect position in the vector
20:48	hiredman	all very immutable
20:48	itistoday	chouser: so, clojure isn't helping me here
20:48	itistoday	chouser: i see that that happens, but i still don't know why
20:48	itistoday	i guess i'm trying to figure out how 'seq' forces it
20:49	itistoday	as well as, what is returned by this: (rest (cons 1 (lazy-seq (println "foo"))))
20:49	steiger	why can't multimethods have '?' in their name? i always get: don't know how to create ISeq from: Character
20:51	hiredman	eh?
20:51	hiredman	pastebin
20:51	itistoday	tomoj: gotcha: (defn rep [f] (lazy-seq (cons (f) (rep f))))
20:52	steiger	hmm, seems it has nothnig to do with '?'
20:53	tomoj	itistoday: yup, that is exactly the source of repeatedly
20:53	steiger	hiredman: http://paste.lisp.org/display/88563
20:54	itistoday	i won't wrack my head about this a anymore
20:54	itistoday	i blame the documentation
20:55	itistoday	will just take hichey's word on it
20:55	rhickey_	,(doc lazy-seq)
20:55	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."
20:56	itistoday	rhickey_: "i guess i'm trying to figure out how 'seq' forces it", and "what is returned by this: (rest (cons 1 (lazy-seq (println "foo"))))" ?
20:57	rhickey_	how seq forces it? you can read the source
20:57	rhickey_	what does how matter for understanding the use?
20:57	itistoday	good point
20:57	hiredman	steiger: and the exception?
20:58	rhickey_	LazySeq.java has the gory details
20:58	steiger	hiredman: Exception in thread "main" java.lang.RuntimeException: java.lang.IllegalArgumentException: Don't know how to create ISeq from: Character (graphutilsNew.clj:9)
20:58	itistoday	rhickey_: thanks
20:58	steiger	sorry, forgot to paste it to pastebin
20:59	hiredman	huh
20:59	hiredman	oh
20:59	hiredman	defmethod's don't take docstrings
20:59	steiger	oh
20:59	steiger	yeah
20:59	steiger	just noticed that
21:00	steiger	that's odd, it feels very natural to put docstrings in defmethods
21:01	hiredman	how would you read the docstring?
21:01	clojurebot	with style and grace
21:01	hiredman	~botsnack
21:01	clojurebot	thanks; that was delicious. (nom nom nom)
21:01	itistoday	how would you read the docstring?
21:02	itistoday	damn bot
21:02	steiger	hiredman: how would i read? using (doc) ?
21:02	hiredman	steiger: but how would you pick out the particular method's docstring?
21:03	itistoday	how would you ______? => "with style and grace" chance of 5%?
21:03	steiger	oh. i see the dilema, hiredman
21:03	hiredman	~literal [?] how
21:03	clojurebot	1
21:03	hiredman	~literal [1] how
21:03	clojurebot	It's greek to me.
21:03	hiredman	~literal [0] how
21:03	clojurebot	<reply>with style and grace
21:04	itistoday	neato
21:04	hiredman	and clojurebot has a 1/100 chance of treating any line not addressed to it as addressed to it
21:04	itistoday	ah, thanks, good to know
21:04	steiger	maybe it should print all avaliable docstrings, i don't know. anyway, eliminating the possibility of having a docstring doesn't feel right
21:04	itistoday	why not put it in the defmulti?
21:05	steiger	defmulti supports it, right?
21:05	itistoday	i've no idea
21:05	steiger	itistoday: yeah, that's what i thought
21:05	steiger	it supports it
21:05	itistoday	:)
21:05	steiger	hm. weird.
21:05	steiger	ok, i'll put it in the defmulti
21:05	hiredman	you have to use the whole #^{:doc "foo bar"} stuff, if I recall
21:06	steiger	hiredman: it compiled nicely with the friendly syntax
21:07	steiger	i.e, after defmulti and the name
21:32	steiger	what's the cleanest way to check if a vector contains an item?
21:33	tomoj	,(.contains ["foo" "bar" "baz"] "bar")
21:33	clojurebot	true
21:33	steiger	thankyou tomoj
21:33	tomoj	of course it's slow
21:33	hiredman	eh?
21:34	hiredman	right
21:34	steiger	i see
21:34	steiger	maybe i should use hashmaps.
21:35	hiredman	well, key looks up would be fast, but not value lookups
21:36	steiger	i gotta think.
21:36	tomoj	key lookups in this case are really just checking whether the vector is at least that long, right?
21:36	tomoj	,(contains ["foo" "bar" "baz"] 2)
21:36	clojurebot	java.lang.Exception: Unable to resolve symbol: contains in this context
21:37	tomoj	,(contains? ["foo" "bar" "baz"] 2)
21:37	clojurebot	true
21:39	arohner	,(some #{:foo} [:bar :foo :baz])
21:39	clojurebot	:foo
21:39	arohner	,(some #{:bogus} [:bar :foo :baz])
21:39	clojurebot	nil
21:39	arohner	of course, that's a linear scan
21:39	arohner	if you want sublinear, use a map
21:39	tomoj	or a set, no?
21:40	arohner	tomoj: yes
22:12	ambient	,(take 10 (rec-cat fibs [0 1] (map + fibs (rest fibs))))
22:12	clojurebot	(0 1 1 2 3 5 8 13 21 34)
22:14	tomoj	is that new? I don't have it
22:14	ambient	clojure.contrib.seq-utils
22:15	tomoj	ah
22:15	tomoj	sweet
23:41	durka42	can clojureql do persistent connections?
23:52	tomoj	durka42: not yet, I believe
23:52	tomoj	btw, coi
23:52	durka42	coi lojbo
23:53	tomoj	there's some discussion about it on the lighthouse
23:54	tomoj	i mi gleki lonu lo lojbo cu pilno la klojur
23:54	durka42	ie la klojur cu logji
23:56	tomoj	ui ji'a melbi