#clojure – 2008-11-27

2008-11-27

00:06	quuxman	jshen: I had the same problem
00:07	quuxman	jshen: I gave up eventually. That was also the advice of a couple other people who were around here
00:07	jshen	hehe
00:07	quuxman	jshen: rlwrap is a little better than nothing
00:07	jshen	i'll just jump to getting oen of the emacs modes working
00:08	quuxman	jshen: yeah, think that's what most people do. I'd be interested to hear how you get SLIME working
00:09	jshen	is that a pain point for a lot of people?
00:09	quuxman	I don't know. I didn't try very hard
00:12	jshen	did you see this? http://en.wikibooks.org/wiki/Clojure_Programming#Emacs_.2F_Slime_Integration
00:12	jshen	I'm going to start there, but not tonight
00:13	mattrepl	jshen: let me know if you run into any hitches. the one gotcha is if you want extra items on the classpath, you need to set those before the requiring of swank-clojure-autoload.el
00:14	jshen	thanks
01:04	yanbe	A lisp compiler for the AVM2. http://github.com/aemoncannon/las3r/wikis/home
01:05	yanbe	perhaps related to this channel
03:18	Lau_of_DK	Top of the morning gents
09:05	mmcgrana	Is this a reasonable / the best way to do a trailing optional arg? : (fn [req-arg & [opt-arg]] (do-something req-arg opt-arg)) I'd prefer not make a second definition with reduced arity.
09:32	Lau_of_DK	mmcgrana: How else would you do it?
09:34	mmcgrana	I couldn't immediately think of one - that was my question.
09:34	mmcgrana	I was just wondering because I think of & as a "vararg" operator not an "optional arg" operator
09:35	mmcgrana	but this works for me i guess
09:35	Lau_of_DK	I cant think of a better way :)
09:35	mmcgrana	het Lau_of_DK I actually have a another question about warn-on-reflection - you ever use that?
09:36	mmcgrana	*hey
09:36	Lau_of_DK	I'd phrase it as: Ive disabled it :)
09:36	mmcgrana	ok
09:46	duck1123	warn on reflection is good if you're into premature optimization
09:49	Lau_of_DK	duck1123: news to me, can you explain what you mean ?
09:50	duck1123	# "We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil. Yet we should not pass up our opportunities in that critical 3%." - Donald Knuth
09:52	notallama	this reminds me: how do you do profiling, when you know something is going slow? just wrap things in a time block until you find it?
09:53	duck1123	notallama: You have all the java profiling tools at your disposal
09:53	Lau_of_DK	notallama: you just hook up the profiler, run the program and read the results :)
09:53	Lau_of_DK	Netbeans JFluid works fine with Clojure
09:54	duck1123	of course, I say this after just getting done profiling two different versions of a function with time
09:56	notallama	these java tools confuse me. : ( i suppose i'll have to learn them eventually, though.
09:57	mmcgrana	Lua_of_DK: is it possible to use JFluid outside of / without Netbeans? I've used YourKit with good results during my free trail period but can't really pay for a license at this point...
09:58	Lau_of_DK	Yes JFluid _should_ be able to standalone, I just downloaded the integrated version because it was so easy to fetch from the plugins list
09:58	Lau_of_DK	@ mmcgrana
10:00	mmcgrana	ok cool, will investigate.
10:00	mmcgrana	Lau_of_DK: thanks
10:00	Lau_of_DK	notallama: It should be TOO confusion. You start your repl with certain paramters. Like for the profiler you start an agent, which stops execution until the profiler connects. So in the end, it makes sense
10:02	Lau_of_DK	notallama: and for the debugger, you dont have to wait for anything, start with appropriate paramters, and code away to your hearts content. When you need it, just attach the debugger to localhost:8888 or whatever port you picked when starting the repl
10:05	notallama	i'm mainly thinking of jswat. it was situations where there's menus and windows /everywhere/. i got it hooked up, and found out how to set a breakpoint, though, so i'm probably not too far grom getting it to do something useful.
10:06	duck1123	has anyone here used jdee for emacs?
10:06	duck1123	I downloaded it, but haven't gotten around to setting it up
10:07	Lau_of_DK	duck1123: jdee?
10:11	duck1123	clojurebot: jdee is http://jdee.sourceforge.net/
10:11	clojurebot	You don't have to tell me twice.
10:12	Lau_of_DK	hiredman: Maybe you should let cb pick on questions without the clojurebot : prefix
10:12	duck1123	fsbot uses the ,keyword syntax
10:13	Lau_of_DK	duck1123: oh... a glorified java-mode :)
10:13	duck1123	Lau_of_DK: it says it has a debugger, so I'm thinking of giving it a try
10:13	timothypratley	what's a good way of of managing shared access (between threads) to a single stream?
10:13	Lau_of_DK	duck1123: looking forward to reading your report
10:14	Lau_of_DK	timothypratley: you mean besides refs ?
10:14	timothypratley	hmmm I assumed ref would only control access to the stream object
10:14	timothypratley	but writting to the stream would still conflict
10:16	timothypratley	ooo maybe an agent
10:16	Lau_of_DK	Commute the reads to the stream, have an agent atomically write out the stream and clear the buffer... how about that ?
10:20	timothypratley	oh... wait commute solves the problem without agents entirely though doesn't it? Because "write" can be the function, and it will be contained in the transaction
10:21	timothypratley	I hadn't thought of that
10:26	Chouser	You might want to use a clojure.lang.PersistentQueue in your collecting ref.
10:35	notallama	anyone know how to set up a classpath properly? i went into my clojure-extras clojure script, and i tried adding some jars and dirs to the path, but no luck. it can't seem to find anything i add, yet it can find jline and clojure.
10:35	notallama	i just put :path.jar at the end of the stuff on the -cp flag.
10:36	Chouser	notallama: that should be all it takes.
10:36	Chouser	java -cp foo/bar/clojure.jar:bing/bang/other.jar clojure.lang.Repl
10:37	Chouser	notallama: are you on Windows?
10:37	notallama	linux
10:38	timothypratley	Chouser: thanks for the tip re PersistentQueue, can you expand a bit on what you mean?
10:39	Chouser	well, that should do it. Then at the REPL you should be able to refer to a class name from the jar: user=> com.fancypants.Other
10:39	Chouser	timothypratley: you used the word "stream" which suggests you might have thread pushing items onto one and of the queue, and some other thread (or threads) pulling them off the other end. thus a queue.
10:40	timothypratley	yup, that's exactly right! :)
10:41	Chouser	so you can have a ref pointing to a persistent queue, push onto it inside transactions, pop from it inside transactions, and you should be all set.
10:41	timothypratley	yup, that's perfect thanks.
10:42	Chouser	on the other hand ... do you want these threads to block on empty queues?
10:42	rhickey	Chouser: exactly
10:42	rhickey	most usage of queues requires workflow
10:43	rhickey	that's why I haven't exposed PersistentQueue yet - I'm afraid of people building polling systems on top of refs
10:44	rhickey	that's also why java.util.concurrent wrappers are on the way - not enough people know about them
10:44	rhickey	but I consider them an important complement to Clojure's facilities
10:44	notallama	i think i tracked down the problem i was having: it doesn't seem to like "~" in the classpath.
10:44	Chouser	rhickey: I just saw clojure code that was doing busy polling on a UI events and a IO events.
10:45	rhickey	Chouser: aargh
10:45	Chouser	It's hard to save programmers from themselves via langauge features.
10:45	rhickey	Chouser: we'll see, when there are queues in the API and examples using them
10:46	rhickey	But yeah, polling sucks and everyone should know that
10:46	timothypratley	in my particular case I do want to block on empty queue, does that put me in the bad category or the good category?
10:46	Chouser	yeah, I guess that's the best hope -- make the right way so easy and obvious that nobody bothers trying the wrong way.
10:46	rhickey	Chouser: right
10:46	timothypratley	great!
10:47	Chouser	timothypratley: it means a PersistentQueue ref is not right for you.
10:47	rhickey	timothypratley: look at java.util.concurrent.BlockingQueue
10:47	timothypratley	damn.
10:47	timothypratley	ok will do
10:47	rhickey	http://java.sun.com/j2se/1.5.0/docs/api/java/util/concurrent/BlockingQueue.html
10:47	Chouser	timothypratley: the fact that you know you want to block is a great sign. :-) You'd find yourself stuck after a while trying to use the PersistentQueue.
10:49	Chouser	hm, and no dosyncs around 'put's or 'take's, right?
10:49	Chouser	those count as side-effects.
10:50	rhickey	Chouser: right, find out you have work, take and do it in a transaction, maybe put after transaction or via action sent in transaction
10:51	rhickey	queues are I/O
10:52	Chouser	non-persistent queues are I/O
10:52	rhickey	Chouser: yeah, I wish they had different names, the workflow queue and the data structure queue
10:52	Chouser	LFE? Is that the io/seq thing from the Haskell slides?
10:53	rhickey	Chouser: yes, cgrand did that nice write-up and I never got back to him
10:54	rhickey	I implemented about half the Haskell system exactly in Clojure - I found it extremely cumbersome and unlikely to be used as is in Clojure
10:54	timothypratley	just to humour me, would this be a terrible way: create an agent which is the stream. I send the stream agent a "send message" function which returns the stream itself. From my very virgin understanding of agents they effectively queue up function calls that transition states (though here I would just be side-effecting). [in reality I'm going to pursue the blockingqueue as I expect to later want to monitor the queue etc]
10:54	rhickey	Too much effort to make iterators chainable, lots of rules to follow in your implementation
10:56	Chouser	Just to make sure I was understanding it despite the Haskell syntax, I tried implementing what I thought were the important parts for the half or so of the slides. I was intruiged at how different my code was from cgrands.
10:56	Chouser	...mainly having to do with what I thought were the important features.
10:56	Chouser	But differing from cgrand is not a great sign, so I'll have to go back through it again at some point.
10:57	rhickey	cgrand based his work on an earlier paper (one I saw Oleg present at LL3), not the slides I mentioned, which is the most recent state of that earlier work
10:58	rhickey	The earlier paper tried to show that you could turn any enumerator into a seq/stream, but in doing so you negate the benefits of LFE in controlling resource lifetime
10:59	Chouser	timothypratley: hm, so your "work queue" would be the agent's own queue and the items of work would be action closures.
11:00	rhickey	the newer work instead focuses on making both iterators and enumerators composable so you don't convert to streams/seqs, but cgrand did to implement multi-collection map
11:00	Chouser	rhickey: ah! ok, that explains some of the different emphasis in cgrand's work.
11:01	Chouser	timothypratley: That would limit you to a single consuming thread, but other than that I can't think of why that wouldn't work.
11:04	rhickey	But the interfaces involved to/from the iterators are pretty complex - possibly empty streams, done states with stream remainders, continuation states with fns of streams - ugh, no wonder it takes 90 slides to explain
11:05	rhickey	Chouser: yes, agents are single-consumer queues
11:14	Chouser	clojure seqs are comparatively simple and tidy.
11:14	Chouser	But resource management is hardly ever simple or tidy, so I guess it's to be expected.
11:18	rhickey	Chouser: right, I want something as simple for io
12:06	notallama	is there a "standard" way to name two-word namespaces? dashes? camel case? underscores?
12:08	Chouser	dashes
12:08	Chouser	which become underscores in file and class names
14:05	AWizzArd	Anyone here who uses Tomcat and/or Jetty?
14:05	blackdog	jetty
14:06	AWizzArd	same here
14:06	AWizzArd	did you also use it in combination with Clojure?
14:06	blackdog	yes,
14:06	blackdog	i do servlets returning json
14:06	blackdog	that's it really, no jsp
14:06	AWizzArd	I want to get it running with Rife
14:06	blackdog	don't know what that is
14:07	AWizzArd	One of the (if not the) most powerful webapplication development frameworks available.
14:07	blackdog	ah
14:08	blackdog	i'm done with web frameworks, i do all my rendering on the client
14:08	AWizzArd	Yes, I will have to think about that as well.
14:08	AWizzArd	Still, there is a lot of stuff to do.
14:09	AWizzArd	Validation of each and every input field. Continuation support, so that the user can go back and forth, scaffolding, etc
14:10	blackdog	if you just return json then you have a very large selection of client side tools, jquery/dojo etc
14:10	blackdog	which can provide a lot of the scaffolding
14:10	AWizzArd	Yeah, I am looking at using dojo as well.
14:36	blackdog	AWizzArd, you need to do ./run test.clj
14:37	AWizzArd	re
15:41	nolbat	how does java make everything so complicated? im trying to translate paul grahams raytracer to clojure. i use javax.imageio but i dont get how to just create an image pixel for pixel.
15:41	nolbat	imagewrite has like 10 different donkeymethods
15:41	AWizzArd	:-)
15:41	AWizzArd	Java is the modern assembler
15:42	AWizzArd	If Java is your only tool then every problem looks like a thumb.
15:52	nolbat	no matching ctor found = constructor
16:09	nolbat	seriously can someone help me with this.
16:10	nolbat	(new ImageReader "C:/users/saftarn/desktop/raytracing.jpg")
16:10	nolbat	doesnt work no mathcin constructor
16:10	nolbat	i have to call some ImageReaderSpi wtf
16:10	nolbat	who writes the javax libs? is it Sun? becaus eif not even the creators of the language can write decent code...
16:11	pdoubleya	nolbat: do you have a working sample in Java? i worked with the imageio apis in the last...hmm, over a year ago, may have some sample code, at least for writing images to a file
16:12	walters	nolbat: ImageReader looks like it's an abstract class
16:13	nolbat	yeah i dont know java evry well, abtsratc this implements extends that.
16:14	walters	nolbat: it looks like you may want just ImageIO.read(new File("C:/users/saftarn/desktop/raytracing.jpg"))
16:14	nolbat	seems like Java was a contribution to an obfuscated C contest then some mistook for a real programming language
16:15	pdoubleya	nolbat: yeah, the imageio lib is pretty complex, from what i recall...but it was aimed at people who need full control over many different image formats...i found it a hassle as well
16:18	nolbat	java.lang.ClassNotFoundException: ImageIO.read (NO_SOURCE_FILE:1)
16:18	nolbat	(import '(javax.imageio ImageIO ImageWriter ImageReader))
16:18	nolbat	how do i import File=
16:18	nolbat	File?
16:19	walters	(import '(java.io File)) looks like
16:20	walters	so all together: (ImageIO/read (File. "/usr/share/icons/abiword_48.png"))
16:20	walters	worked for me
16:20	walters	but i don't actually know Clojure, only Java so take it with a grain of salt =)
16:29	nolbat	ah nice
16:32	AWizzArd	I would really like to know how many of you are actually coming from Java, from CLand from something else.
16:34	kotarak	AWizzArd: coming from Scheme, Perl, Ruby, C, pick one.... :)
16:44	nolbat	have minor java knowledge(tried and hated it). know Python very well adn scome Scheme, haskell, C, little C++
16:46	nolbat	wanted to learn lisp more and scheme and cl didnt have a practical platform.
16:48	nolbat	so: ImageIO.write(rendImage, "png", file);
16:48	nolbat	becomes what ? (ImageIO/write rendImage "png" file) ?
16:48	rotty	walters: hi there! didn't know you were into lisp :-)
16:49	nolbat	Does CLojure use Javas green threads?
16:49	walters	hey rotty! well, clojure has a lot of interesting ideas I think; the readonly data structures with structural sharing, the STM etc. I'm not totally sold on Lisp, but I'm pretty sure some of Clojure's DNA is going to start appearing in new languages at least
16:49	walters	(and existing ones)
16:50	walters	nolbat: OpenJDK hasn't used green threads since the mid 1990s
16:51	rotty	yeah, clojure is pretty interesting. I've yet to try it -- still sticking with Scheme so far...
16:53	notallama	i know a bit of java, c, scheme, and a tiny bit of python (i found python irritating.) i have not really written much of anything though. just school type stuff. clojure's by far the nicest, though.
16:54	AWizzArd	Not all are in the lucky position to be paid Clojure developers g
16:56	nolbat	notallama: what did you find annoyin about python?
16:58	notallama	i think it was the lambdas. they set my brain in scheme mode, but they're not really the same as scheme lambdas. it's probably somehting i'd get used to if i used it more.
16:59	kotarak	the python lambda doesn't deserve the name...
17:00	nolbat	so whatever
17:00	nolbat	they do everything i need
17:00	nolbat	big deal
17:03	notallama	it's probably the same idea as trying to use java style in scheme. it just doesn't work well.
17:04	nolbat	but you can do most of what u need wiht python lambdas
17:05	notallama	with c and java, i had classes to figure out what idiomatic code looks like. with scheme, there's sicp. with python, i just wasn't sure what i was doing. i'm not saying python is bad, just that my first attempt at it didn't go well.
17:06	nolbat	>>> map(lambda x: x2 if x < 5 else x3, range(10))
17:06	nolbat	[0, 1, 4, 9, 16, 125, 216, 343, 512, 729]
17:07	AWizzArd	walters: it is not dramatically different in Clojure. There you also have no "private" data. And you will store lot's of your data in hash maps :-)
17:09	walters	AWizzArd: right, but Clojure doesn't claim to be an object oriented system, which is fine; I agree for concurrency the readonly data structures make more sense, but object orientation (without the need for concurrency) makes a lot of sense in other problem domains like GUIs
17:11	notallama	clojure can do oo now, with gen-class. has private methods too.
17:12	AWizzArd	we want to try to avoid that as much as possible
17:12	notallama	oh? how come?
17:12	hiredman	(doc defn-)
17:12	clojurebot	same as defn, yielding non-public def; arglists ([name & decls])
17:13	hiredman	speaking of private
17:14	AWizzArd	notallama: because Clojure is a functional programming language and I personally believe that the functional paradigm has more use in many cases
17:15	AWizzArd	It is declarative.. you say what you want to do, and not how to do it.
17:17	nolbat	i wrote a basic OO-system in clojure, it is not hard
17:17	nolbat	but i dont need it
17:17	nolbat	just using Maps and multimethods works fine
17:17	notallama	i don't really see where the conflict is. you have a function that maps some set of objects onto some other set of objects.
17:19	nolbat	which conflict?
17:21	notallama	AWizzArd was saying that we want to avoid oo with gen-class because functional is more useful (i interpreted it that way, anyway). so your question is pretty much a repeat of mine.
17:22	nolbat	ah
17:22	nolbat	i still havent figured out how to write to an mage
17:23	nolbat	like in Python I just look these things up and then do it. with java...
17:25	notallama	did you look at the compilation section on the clojure site?
17:27	nolbat	i never have to throw and catch checked exceptions n Clojure?
17:29	AWizzArd	nolbat: we want to go away from telling the computers how to do things. The direction should be: saying what we want and let them figure out how to do it.
17:30	AWizzArd	to some extent a functional programming style is exactly that. When you write a fibonacci function you have not programmed anything. You wrote down the mathematical definition.
17:35	kotarak	(doc refer)
17:35	clojurebot	refers to all public vars of ns, subject to filters. filters can include at most one each of: :exclude list-of-symbols :only list-of-symbols :rename map-of-fromsymbol-tosymbol For each public interned var in the namespace named by the symbol, adds a mapping from the name of the var to the var to the current namespace. Throws an exception if name is already mapped to something else in the current namespa
17:35	notallama	right. but don't you still need the computer to have some description of what the function is operating on? (i'm aware that you can construct natural numbers from lambdas, but it's certainly helpful to have first class integers. why not extend that to objects?)
17:35	nolbat	(defn writeFile [image format path]
17:35	nolbat	(ImageIO/write image format (File. path)))
17:35	nolbat	works
17:36	AWizzArd	notallama: of course, a program without side effects makes no sense and is very boring
17:37	AWizzArd	I just want to minimize and centralize them
17:38	rotty	btw, is there any chance that clojure might get call/cc at some point in the future?
17:38	AWizzArd	You can do that with threads
17:38	notallama	i don't know a lot about call/cc, but trampoline seems like it's getting close.
17:39	rotty	notallama: I think trampolines are about proper tail calls
17:39	rotty	AWizzArd: how so?
17:39	AWizzArd	and well, you could implement them yourself rotty, you have macros
17:40	AWizzArd	threads and their environment
17:41	nolbat	anyway good with imageio? i can open a file and write to another file but i dont get how to manipulate it, it is funny how for all its documentation, static typing JAVA stillf ails to get to the point and tell wtf a method is actully doing. it just passes classes here and there
17:41	AWizzArd	rotty: do you know http://www.paulgraham.com/onlisp.html already? It's maybe the best book about macros in Lisp. Paul Graham implements continuations in there. You can download the book (legally) for free there.
17:42	AWizzArd	nolbat: I know how you feel.. it seems the authors wanted to put in everything at an extremly fine granularity
17:43	notallama	rotty: it is for that, but it works by passing a function and an environment around. i just have a hunch that it's about 2 macros away from call/cc.
17:44	walters	nolbat: it looks like you need to call createGraphics to get a graphics context; then there are a bunch of drawing methods on that
17:45	drewc	notallama: my pet project is an implementation of delimited continuations for clojure.
17:45	walters	nolbat: or if you want to get/set pixels, you can call getRaster
17:46	drewc	trampolining was the technique i was playing with prior to it being included, and it is indeed a good start.
17:47	nolbat	walters: ah iw ant toget/set pixels , thanks
17:47	drewc	rotty: that's honestly not the best introduction to either call/cc or on how to implement it IMO.. but it is somewhat accessible.
17:48	drewc	rotty: just don't go getting the idea that his method is the only, or the best, way to hack up call/cc on top of a lisp that doesn't offer it :)
17:48	nolbat	what d i call getRaster on? i cant find the method
17:49	walters	nolbat: BufferedImage
17:50	kotarak	Does anyone experience problems with the latest SVN?
17:50	kotarak	In particular with use/require?
17:58	nolbat	im a bit unsure on the whole how to use JAVA from clojure. if i pass a BufferedImage to a funciton and want to do getRaster on it, whats it he correct way.
17:58	kotarak	(.getRaster your-buffered-image)
18:21	nolbat	http://java.sun.com/javase/6/docs/api/java/awt/image/WritableRaster.html
18:25	nolbat	so i have my raster and want to do setPixel, how do i supply an areay?
18:25	nolbat	is that array meant to rep the color?
18:28	nolbat	#<ByteInterleavedRaster ByteInterleavedRaster: wid
18:28	nolbat	is what i get but i should get WritableRaster
18:29	nolbat	and then it says no setColor for ByteInt...Raster
18:30	walters	nolbat: http://clojure.org/java_interop#toc26
18:47	nolbat	one thing i dont get with the clojure mentality is. lets say i want the equivalence of an Image-class, how would abstract that in CLojure?
18:48	nolbat	i mean thats a thing where i normally think of some sort of entity/object with attached methods
18:48	AWizzArd	nolbat: a structured map with some functions operating on it, in it's own namespace
18:50	AWizzArd	so instead of having a class person with the fields name, age, address you will have a (defstruct person :name :age :address)
18:53	nolbat	ah i see
18:54	nolbat	can i check the type of a java-object at runtime?
18:55	nolbat	yes class
18:56	walters	nolbat: (.getClass foo)
19:00	nolbat	so if i want to collect a bunch of clojure-functions for image-stuff. should i put it in its own namespace?
19:01	nolbat	sun.awt.image.ByteInterleavedRaster is what i get but according to the docs i should get WritableRaster. anyone could guess why?
19:03	lisppaste8	nolbat pasted "raster-problems" at http://paste.lisp.org/display/71140
19:06	walters	nolbat: groovy:000> WritableRaster.class.isAssignableFrom(ByteInterleavedRaster.class)
19:06	walters	===> true
19:06	walters	(i don't know how to refer to class literals in clojure, so using groovy syntax)
19:08	nolbat	i dont know java to well so what does that mean? how do i go from Byteratser to Writableraster?
19:09	walters	the ByteInterleavedRaster is a WritableRaster, it subclasses it
19:11	nolbat	ok, but t doesnt have that methods
19:12	nolbat	wait wtf
19:12	nolbat	setPixel it should be wtf was i thinking
19:12	nolbat	still deosnt work though :)
19:13	Chouser	user=> (isa? sun.awt.image.ByteInterleavedRaster java.awt.image.WritableRaster)
19:13	Chouser	true
19:13	nolbat	java.lang.IllegalArgumentException: No matching method found: setPixel for class sun.awt.image.ByteInterleavedRaster (NO_SOURCE_FILE:0)
19:14	walters	as for how you set the pixels, it looks like the format depends on samples, and it isn't immediately obvious to me how it works
19:14	Chouser	nolbat: that error often means the argument types are incorrect.
19:14	walters	i haven't actually done any awt or swing since the late 1990s, and am in fact right now actively working to replace both of them =)
19:14	nolbat	anything wrong with them? arent they the most used ones in java?
19:18	walters	nothing strictly speaking wrong with them, particularly if you care about cross platform
19:18	Chouser	nolbat: setPixel takes an array of int, float, or double. into-array cannot produce any of those.
19:27	Chouser	(doc int-array)
19:27	clojurebot	Creates an array of ints; arglists ([size-or-seq] [size init-val-or-seq])
19:32	nolbat	but is int-array a java-array?
19:32	nolbat	or i ahve to do into-array (int-array?
19:33	nolbat	what does it mean when a JAVA method returns NIL? java method retuns nothing? just does its sideffect?
19:33	nolbat	so it workd?
19:34	Chouser	seems likely, yes.
19:34	Chouser	yeah, setPixel returns void, so if you should expect nil
19:34	Chouser	no exception is a good sign.
19:37	nolbat	im learning image analysis, clojure seem to be good because it connects to java, allows for easy parallell processing. is there an interface to matlab?
19:37	nolbat	would it possible to create?
19:38	nolbat	if i want to create an imaging-module, i then put it in its own namespace
19:38	nolbat	(in-ns 'imaging)
19:38	nolbat	but when i import in that fle i get import not recognized or soemthing
19:40	nolbat	should i import to the namespace or soemthing?
19:51	Chouser	in a file, use 'ns' instead of 'in-ns'
19:53	Chouser	and namespaces ought to have at least one package-part
19:53	nolbat	java.lang.ClassCastException: clojure.lang.PersistentList cannot be cast to clojure.lang.Symbol (imaging.clj:0)
19:53	nolbat	package-part? i thought that was the name-space
19:56	nolbat	#<imaging$get_image__2587 imaging$get_image__2587@1332109>
19:56	nolbat	(ns imaging)
19:57	Chouser	(ns nolbat.imaging (:import (java.awt.image WritableRaster)))
19:58	nolbat	you mean imaging should be part of a package?
19:58	nolbat	why?
19:58	Chouser	namespaces map to class names, and Java class names should be in a package.
20:51	nolbat	using setPixel should be enough right?
20:51	nolbat	on a Raster
20:52	Chouser	enough for what?
20:52	lisppaste8	nobalt pasted "writing-image" at http://paste.lisp.org/display/71145
20:52	nolbat	im trying to write a line on a white image.
20:57	Chouser	I don't know the APIs involved at all. you might want to try translate a Java example to begin with.
21:08	Flox_	nolbat: If you want something interactive accessible from Clojure, you might be interested in Fiji (http://groups.google.com/group/clojure/browse_thread/thread/15f566f12cc485a4/8b2a5b1a0dc61c87?lnk=gst&q=imagej#8b2a5b1a0dc61c87).
21:08	Flox_	That way, you would have access to all existing ImageJ image analysis plugins from Clojure...
21:09	nolbat	cool
21:10	nolbat	wow cool exactly what iw as thinking about creating :)
21:14	Flox_	nolbat: Don't look at what Albert Cardona has achieved using ImageJ. It will make your eyes pop out...
21:15	rsynnott	presumably the JVM would make returning multiple values similar in perfirmance to using a vector, anyway
21:16	Flox_	I can't wait to see the first multithreaded image transformation and analysis plugins appear - thanks to Clojure!
21:17	Flox_	Good night!
21:23	nolbat	Flox_: thats what im want to learn, image processing si perfect for parallellism(embarassingly parallell)
22:16	nolbat	ok i have a java-version fo what iw ant to do now. this is good btw cuz im learning java at the same time which you kind of have to no matter what you think of it right, its seems to be everywhere?
22:17	nolbat	but my main problem in mky head is
22:17	nolbat	java is sideffectful, clojure is functional
22:17	nolbat	so when oing with sideffects im a it confused here
22:19	lisppaste8	nolbat pasted "writing to image" at http://paste.lisp.org/display/71148
22:19	nolbat	someone can have a look?
22:24	nolbat	plz
22:31	nolbat	noone there?
22:32	nolbat	http://paste.lisp.org/display/71148
22:32	nolbat	(for [x (range 300 300)]
22:32	nolbat	(for [y (range 300 300)]
22:32	nolbat	(.setRGB buffered-reader x y rgb-color)))
22:32	nolbat	something wrong with that?
22:35	durka	i don't really know clojure yet but the range in the paste looks a little strange
22:35	nolbat	am i that annoying? everyone put me on ignore?
22:35	nolbat	oh well lol
22:35	durka	and different from the range you just typed
22:35	nolbat	but that isnt the problem it still doesnt work for 200 300
22:37	durka	hmm
22:38	lisppaste8	fdg annotated #71148 with "fdgfdg" at http://paste.lisp.org/display/71148#1
22:38	nolbat	wait i might see
22:38	nolbat	no it should be ok
22:39	nolbat	ah wait
22:39	nolbat	no that should be ok too :(
22:42	nolbat	or somehow the buffer im updating isnt the one im writing to the file?
22:44	nolbat	durka why does the range in the paste look strange?
22:45	durka	well the one in the annotation doesn't
22:45	durka	but range(100 200) doesn't look like lisp
22:45	nolbat	nah i hcnaged that
22:46	nolbat	but as i see it i do exactly like the JAVA version
22:48	nolbat	setRGB is void
22:48	nolbat	does for need a return value?
22:59	nolbat	imaging> (.getRGB (get-image rt) 10 20)
22:59	nolbat	-1
22:59	nolbat	imaging> (.getRGB (set-pixel (get-image rt) 10 20 212) 10 20)
22:59	nolbat	-16777004
22:59	nolbat	-16777004 is also the value iget in java
22:59	nolbat	but also for 112 or 212 as setRGB-value
23:05	dlonki	ok now i can set one pixel
23:05	dlonki	it must be something with the looping
23:06	dlonki	what does for do exactly? form some sort of clouse or soemthing where the image inside is something else than the image outside?
23:16	dlonki	ok so i can do change one pixel and save it
23:16	dlonki	i cant use map and ic ant use for
23:16	dlonki	maybe loop recur?
23:24	dlonki	wow faakkking finally
23:24	dlonki	it worked with looop recur
23:24	dlonki	map and for-comprehensions dont work, i have to pass along the picture
23:26	notallama	what was it you were trying to do?
23:26	dlonki	editing a picture
23:27	dlonki	BufferedImage
23:27	dlonki	and then give it a range of pixels to change to a specific color
23:27	lisppaste8	ak annotated #71148 with "loop-recur works!" at http://paste.lisp.org/display/71148#2
23:28	dlonki	that took several hours lol
23:28	notallama	that sounds lime something you could do with doseq and for.
23:28	dlonki	well for didnt work, maybe i was doing it wrong
23:28	notallama	what was your for?
23:29	notallama	for is lazy, so if you were trying to do side effects with it, that's your problem.
23:30	dlonki	aha
23:30	dlonki	u can see it all^^
23:34	notallama	what's vs?
23:34	dlonki	oh i changed to vector-pairs
23:34	dlonki	[[1 2] [2 4]] etc
23:34	dlonki	or (map vector (range 100) (range 100 200))
23:35	dlonki	im trying to do a doseq but dont quite get it
23:38	notallama	(doseq [[a b] vs] (set-pixel image a b color)) or something. it binds to the first thing in the seq, and does the body, then the second, etc.
23:40	notallama	the syntax might be different depending on what version you're using. the old one didn't have the square brackets around the binding forms.
23:53	dlonki	ah yes doseq is elegant
23:53	dlonki	what about laziness make for not work?
23:54	notallama	only the first thing in the seq gets evaluated.
23:54	notallama	the rest of it waits for something to call "rest" on the seq.
23:56	dlonki	so i should what? is there some way force it?
23:58	danlei	clojurebot: dorun?
23:58	clojurebot	Titim gan ?ir? ort.
23:58	danlei	(doc dorun)
23:58	clojurebot	When lazy sequences are produced via functions that have side effects, any effects other than those needed to produce the first element in the seq do not occur until the seq is consumed. dorun can be used to force any effects. Walks through the successive rests of the seq, does not retain the head and returns nil.; arglists ([coll] [n coll])