#clojure – 2008-12-22

2008-12-22

00:03	hiredman	the hard drive in the machine that was running clojurebot died
00:24	Chouser	hiredman: :-(
00:25	hiredman	it maybe a week or two before it gets rebuilt
00:50	joha1	would like to get unbuffered console input (e.g. pressing a key should return at once, instead of waiting for ENTER), preferably without having to use something big like JCurses. So far I'm failing. Any ideas?
00:56	Chouser	joha1: in C you'd use tcsetattr to set the terminal's parameters
00:58	joha1	yes, I tried something similar with stty (I'm on Linux). Didn't work, but perhaps my mistake
00:59	Chouser	ah, shelling out to stty?
00:59	Chouser	that rings a bell...
00:59	joha1	well, I couldn't make it work, but perhaps you have seen something similar?
01:00	Chouser	not from java/clojure, but I'm pretty sure I've done it. maybe from perl?
01:00	joha1	Hmm, perhaps I should google a bit more. I already tried "stty -icanon min 1"
01:05	Chouser	try adding "time 0" to that
01:11	Chouser	I don't think that's it.
01:12	Chouser	you're using Runtime's .exec method?
01:19	joha1	chouser: yes i am
01:19	joha1	must be a better way
01:19	Chouser	ok, the problem is that the sub-process is run in a way that's not associated with the terminal
01:20	joha1	makes sense
01:20	Chouser	if I add -F /dev/pts/termnum to the stty command line, it works
01:20	Chouser	so, what to use for termnum?
01:20	Chouser	I tested by running "tty" on the command line and copying the result into my test program manually.
01:21	Chouser	but I don't know if there's anyway to get the terminal associated with the java process's stdin
01:22	joha1	running tty from Runtime.exec would give the tty for the new process instead, right?
01:22	Chouser	right.
01:22	Chouser	trying that got me back the string "not a tty"
01:23	joha1	in worst case I could always to to get JCurses to work. Much overhead for something so simple, though...
01:24	joha1	thanks anyway
01:24	Chouser	or use Swing. :-)
01:24	joha1	sure, but sometimes you just need a text console
01:24	joha1	:)
01:24	Chouser	I think you mean a JTextPane
01:24	Chouser	sometimes you just need a JTextPane
01:25	joha1	not if I don't have X on my server
01:26	zakwilson	People have X on servers?
01:29	Chouser	joha1: you could do the stty setup/teardown in a launching script
01:31	joha1	I've just found a page describing how to set up nonblocking input in Java using the stty method
01:31	joha1	http://www.darkcoding.net/software/non-blocking-console-io-is-not-possible/
01:31	joha1	will try to get this working in clojure
01:32	joha1	but of course I could set it up in a calling script as well
01:36	Chouser	huh, he bounces it through "sh -c ... < /dev/tty" and apparently that does it.
01:39	Chouser	oh, nope, I screwed up my test.
01:47	joha1	Yeah, this works!
01:47	joha1	(import '(jline ConsoleReader))
01:47	joha1	(.readVirtualKey (new ConsoleReader))
01:47	joha1	and there are lots of other useful functions in Jline
01:47	Chouser	:-)
01:58	lisppaste8	Chouser pasted "unbuffered input at text terminal" at http://paste.lisp.org/display/72515
01:59	joha1	nice
02:00	Chouser	but if jline of jcurses is an option, I'm sure you'll have better results there.
02:01	joha1	it will certainly be easier, and multi-platform. Still interesting to know that it can be done
04:10	klinkers	how fast is Clojure?
04:10	klinkers	benchmarks?
04:14	leafw	klinkers: as fast as java.
04:15	leafw	but, considering it enables better algorithms, your programs may be faster than naive, imperative implementations in java.
04:18	klinkers	enables bette ralgorithms?
04:18	klinkers	dont yu always have more options in java? you can do inplce sorting etc
04:18	klinkers	ormaybe you cna in clojrue too
04:19	klinkers	anyway does AOT mean I can compile to a JAR? and that other java-libs can use my clojure code?
04:19	leafw	yes.
04:26	lisppaste8	leafw pasted "benchmark" at http://paste.lisp.org/display/72517
04:26	leafw	klinkers: have a look for yourself.
04:26	leafw	it's a very simple benchmark, adding numbers.
04:34	klinkers	janino?
04:35	klinkers	clojure wih primitives is that doing things like : (+ (int 5) (int 6)) ?
04:37	leafw	and type declarations.
04:44	klinkers	that is a type declaration no?
04:49	leafw	well, (int 5) is a type declaration indeed, although I can't help thinking of it as a cast (but it isn't)
04:50	leafw	although (int 1.5) prints 1.
04:50	leafw	"Coerce to int", (doc int) says.
05:00	klinkers	clojure.examples.hello
05:00	klinkers	is clojure and examples directories then?
05:01	hoeck	klinkers: right
05:02	hoeck	./clojure/examples/hello.clj
05:05	klinkers	hmm i use september there fore compiel is not working?
05:06	leafw	klinkers: pull svn
05:08	hoeck	klinkers: or use the clojure pre realease
05:08	hoeck	(the download link on clojure.org)
06:18	bOR_	Hi all, I ran into: java.lang.Exception: Transaction failed after reaching retry limit (NO_SOURCE_FILE:0)
06:18	bOR_	and on the forum I see that stuart sierra ran into the same thing, and rich recommended not using a wait function.
06:19	bOR_	wondered if the official (await ... ... ..) is also a dont-use-this-in-very-long-loops wait function
06:19	bOR_	http://groups.google.com/group/clojure/browse_thread/thread/c8c3510f01f951e1/a2b74c4fd85c89bb?lnk=gst&q=retry+limit#a2b74c4fd85c89bb
06:22	bOR_	it seems that all elements in my vector of refs are locked now.
06:22	bOR_	mm.
06:23	fyuryu	bOR_: I can't really answer your question, never encountered the problem so far, but try asking in a couple of hours (5-6)
06:23	fyuryu	bOR_: and a source snippet would help
06:23	bOR_	I'll drop it into the forum then.
06:26	fyuryu	try structuring the code differently, waiting in a loop doesn't seem like a goo idea (but without knowing what you want to do exactly, it's hard to tell)
06:26	fyuryu	maybe agents would be a good fit for you task?
06:29	fyuryu	bOR_: oh wait, you're using await in that loop?
06:35	jgracin	replaca: fantastic job on cl-format! I was hoping someone would do it eventually, and this was quick.
06:43	bOR_	(sorry, was cleaning my bike). I've 8 agents that each are send off in a loop, at the end of sending them off, I await them all.
06:43	bOR_	the loop itself is a million times.
06:43	bOR_	(but I'm not sending off 8 million agents at the same time)
06:43	bOR_	(just 8)
06:44	bOR_	each agent has the task of doing 7 things to every reference in a vector, in random order.
06:44	bOR_	and right now, while we're no longer in a loop or anything,
06:45	bOR_	I can't even do a single thing to a single ref anymore without it failing due to many retries.
06:45	bOR_	is there any way to see which refs are all locked right now, and by whom they are locked?
06:54	fyuryu	and how big is the vector that the agents operate on?
06:55	bOR_	vector of 1000 refs
06:56	bOR_	it's an agent-based model. each ref might contain a host, and the 7 things I'm doing to them are birth / death / evolution / infection.
06:57	bOR_	thanks for talking though, will help in knowing what information to put in the google group post.
06:58	fyuryu	bOR_: I don't think there is a way to see who locks the refs in a given moment
06:59	bOR_	think I know..
06:59	bOR_	based on doc await.
06:59	bOR_	if there's one of the transactions not returning.
06:59	bOR_	await just keeps blocking everything, I guess.
07:00	fyuryu	ah, so you're not sure if every agent completes his work?
07:00	bOR_	as await might still be waiting for one of the (send-off) to finish.
07:00	bOR_	normally it should.
07:00	bOR_	and it tends to
07:01	bOR_	but maybe if for some reason I don't know yet, one of the send-off agents blocks.
07:01	bOR_	ok..
07:01	bOR_	that's a good question.
07:01	bOR_	what happens with await, when one of your threads runs into the retry limit.
07:02	fyuryu	(doc await-for)
07:02	bOR_	gracias. that might work indeed.
07:02	bOR_	normally, a single year takes about 60 seconds to compute.
07:03	bOR_	well, sometimes 90
07:03	bOR_	so I can just put the await on 3 minutes.
07:04	bOR_	I'll make a post, cause I wonder what happens with the thread that didn't return on await.
07:24	klinkers	im trying to compile but the examples are not so easy
07:24	klinkers	ok i have a file C:/clojure/progs/hello.clj
07:24	klinkers	how would I compile it?
07:24	klinkers	hte namespeace should contain :gen-class?
07:24	klinkers	and the compeltr apth?
07:25	leafw	klinkers: http://pacific.mpi-cbg.de/wiki/index.php/Clojure_Scripting#Generating_java_classes_in_.class_files_from_clojure_code
07:26	leafw	klinkers: http://clojure.org/compilation
07:49	klinkers	yes but what im wondering voer is namespaces
07:50	klinkers	if i ahve a file
07:50	klinkers	C:/clojure/progs/hello.clj
07:50	klinkers	what namespace should i put it in?
07:51	Chouser	klinkers: they only way for that path to be a valid lib would be if it has the namespace progs.hello (and C:/clojure is in your classpath) or the namespace clojure.progs.hello (with C:/ in your classpath)
07:54	klinkers	i have C:/clojure in my classpath and I have the file int he namespace progs.hello
07:55	klinkers	i do (compile 'progs.hello) and i get:
07:55	klinkers	java.io.IOException: The system cannot find the path specified (hello.clj:1)
07:55	klinkers	user=>
08:00	fyuryu	klinkers: "progs.hello" namespace == "c:/some-path/progs/hello.clj", and c:/some-path AND c:/some-path/classes must be in your classpath.
08:04	klinkers	java.io.IOException: The system cannot find the path specified (hello.clj:1)
08:04	klinkers	progs.hello=>
08:04	klinkers	what is classes there btw?
08:04	klinkers	the classes it uses u mean?
08:05	Chousuke	klinkers: the classes dir contains the compiled code
08:05	Chousuke	or will contain
08:05	Chousuke	it needs to exist and be in the classpath before compilation though.
08:05	klinkers	http://hpaste.org/13252
08:06	Chousuke	which I think is not very nice, but I don't know a way around it either.
08:06	klinkers	should it be called classes?
08:07	Chousuke	klinkers: you don't need str with println btw.
08:07	Chousuke	it can take multiple arguments.
08:07	acieroid	how can I cast an Integer to a Char with clojure ?
08:07	klinkers	still: progs.hello=> java.io.IOException: The system cannot find the path specified (hello.clj:1)
08:08	Chousuke	you'll want your classpath to contain C:/clojure/;C:/clojure/classes/
08:09	Chousuke	along with the others
08:09	Chousuke	and remove the entry with hello.clj in it
08:09	kogu	acieriod: char?
08:09	acieroid	hum
08:09	acieroid	forgot this function ><
08:09	Chousuke	klinkers: and make sure C:/clojure/classes/ exists
08:10	kogu	ok, im really new to lisp, can someone help me with this really basic thing?
08:10	kogu	http://hpaste.org/13253
08:11	kogu	it always prints 0
08:11	klinkers	you should use if
08:11	klinkers	instead of when
08:11	klinkers	i think
08:11	acieroid	no
08:11	Chousuke	no
08:11	acieroid	because data are immutables
08:11	klinkers	yes and branch
08:11	Chousuke	kogu: + does not change points
08:12	klinkers	ah ysw recur points
08:12	Chousuke	kogu: it only outputs a new value, which is promptly discarded
08:12	kogu	i see, so how can i use a global variable for points?
08:12	acieroid	with refs
08:12	rhickey	could everyone please use paste.lisp.org please? then we get a single archive to look back through
08:13	rhickey	lisppaste8: url
08:13	lisppaste8	To use the lisppaste bot, visit http://paste.lisp.org/new/clojure and enter your paste.
08:13	Chousuke	kogu: once you (let [points 0]) points is 0 and will not change
08:13	kogu	ok, so how do i define a variable which will change
08:13	Chousuke	kogu: for that code, you don't.
08:14	Chousuke	kogu: simply modify the logic to call recur in a way that passes the change to the next loop :)
08:14	kogu	ah i see, that makes sense, thanks a bunch, emacs you bastard, here i come
08:14	Chousuke	but if you really need a global "points" state, the way to do that is to use a ref and dosync
08:15	kogu	i haven't gotten to that part yet, but i will keep that in mind
08:15	Chousuke	but surprisingly many apps don't even need refs
08:16	Chousuke	you can also have state as something that is passed to each function and they then return a new state
08:18	kogu	hmmmm
08:18	kogu	have to grok it, still think in java
08:18	kogu	one more ques, how can i do a lot of if elseif elseif else?
08:19	Chousuke	cond
08:19	kogu	wow, thats right
08:19	kogu	ty again
08:21	Chousuke	using (or) can also be useful if you need to stop as soon as you get something non-false
08:23	Chousuke	or returns the first non-false value as is, so the following will work assuming the search function returns nil if an item is not found: (defn get-item [] (or (search source1) (search source2) :default-item))
08:24	klinkers	acieroid: Integer.
08:25	acieroid	klinkers, char works perfect
08:27	klinkers	and it should be c:/clojure/classes/ not c:/clojure/progs/classes or anything?
08:27	klinkers	progs.hello=> (apply char "2")
08:27	klinkers	\2
08:27	klinkers	progs.hello=> (Integer. "2")
08:27	klinkers	2
08:29	Chousuke	klinkers: yeah, c:/clojure/classes/
08:31	klinkers	so what could i be missing?
08:31	klinkers	java.io.IOException: The system cannot find the path specified (hello.clj:1)
08:31	klinkers	i ahve the correct paths in the classpath
08:32	klinkers	path specified (hello.clj
08:32	klinkers	should that says the whole pth to hello.clj?
08:32	Chousuke	no.
08:33	Chousuke	does the classes dir exist?
08:33	Chousuke	it must exist when you start the VM
08:33	hoeck	klinkers: have you set compile-path to "c:\\clojure\\classes" ?
08:34	Chousuke	shouldn't that be the default.
08:34	klinkers	oh
08:34	klinkers	where is compile-path?
08:34	klinkers	where do is et it anyway?
08:34	Chousuke	in your clojure program
08:34	hoeck	it defaults to "classes"
08:35	Chousuke	a simple (set! compile-path "c:/clojure/classes") at the top of your script should do I guess.
08:35	klinkers	set! ?
08:36	hoeck	or do (binding [compile-path "bla\\foo"] (compile 'clojure.expamples.hello))
08:36	klinkers	u emand ef?
08:37	hoeck	compile-path is bound above the repl so you can set! it
08:37	klinkers	im using emacslisp in clojure then?
08:37	Chousuke	no.
08:37	Chousuke	compile-path is a clojure setting, not an emacs one
08:38	klinkers	hello mama!
08:38	klinkers	there it worked
08:38	klinkers	it egenrates a bunch of .class stuff
08:39	klinkers	then i can compile that to a JAR with javac!?
08:39	Chouser	I use the 'jar' command to produce a .jar file
08:42	klinkers	exactly how? you mvoe to ~/classes/ and then?
08:43	klinkers	or jsut form anywhere(mind me i dont know java tow ell)
08:43	kogu	klinkers: you just zip that folder, and rename it's extension to .jar
08:44	kogu	klinkers: make sure that the folder path is preserved
08:47	Chouser	kogu/hoek: you can set up the manifest correctly like that?
08:48	kogu	cho: usually if you don't have a main class, you don't need the manufest file
08:48	Chouser	ah, ok.
08:49	klinkers	jars a re zipped .class-collections?
08:49	Chouser	klinkers: yes
08:49	Chouser	with some (apparently optional) extra header info
08:50	kogu	jars, wars, *ars
08:50	kogu	all the same
08:50	klinkers	so i should have another word between progs and the actual program then
08:54	lisppaste8	kogu pasted "untitled" at http://paste.lisp.org/display/72523
08:54	kogu	ummm, how to i return the points from that function?
08:55	Chousuke	kogu: use let instead of def
08:55	Chousuke	kogu: and: (do (println points) points)
08:55	klinkers	kogu: exactly what are yout rying to do? idiomatically you shouldnt use de flike that
08:55	Chousuke	print*
08:56	kogu	cho: print is just for debugging
08:56	kogu	cho: im loopping 10 times, creating a new roll each time, eval the roll and adding points accordingly
08:57	Chousuke	kogu: oh right.
08:57	Chousuke	kogu: I misread that thing :P
08:57	Chousuke	use if instead of when then
08:57	Chouser	change your (when (> counter 0) ...) to (if (zero? counter) points (do ...))
08:58	kogu	cho: ah i see, ty, so i change def -> let, and change when->if
08:58	kogu	cho: ty
08:58	Chouser	right -- those changes are related, but you need both.
08:58	Chouser	those changes are NOT related, but you need both
08:59	kogu	cho: right, let because i want it scoped locally, and if to return the points
08:59	Chouser	right
08:59	Chousuke	kogu: (if (> counter 0) (let [roll (new-roll)] (print points) (recur (dec counter) (+ points (eval-roll roll)))) points)
08:59	Chousuke	parentheses may not match...
08:59	Chouser	well, also 'let' because 'def' inside a function like that is icky.
09:00	hoeck	kogu: or do (reduce + (take 10 (repeatedly new-roll)))
09:04	Chousuke	or because you need eval-roll: (reduce + (take 10 (repeatedly #(eval-roll (new-roll)))))
09:05	kogu	cho: whoa!!!
09:05	kogu	let me try that
09:14	kogu	cho: dude! that was awesome, that worked like a charm
09:17	Chousuke	it was hoeck's idea though. I just fixed it to match your code. :)
09:18	Chousuke	often you can use the higher-order functions and reduce instead of explicit loops.
09:19	kogu	cho: well i got both working, i need to look into this reduce, never used this before
09:23	Chousuke	kogu: reduce is a function which takes a function of (at least) two arguments and a sequence, then applies that function to the first two values of the seq, then again to the result and the next value in the seq, etc.
09:24	kogu	hmmm, never thought it could be used like this
09:24	Chousuke	so (reduce + [1 2 3 4]) = (+ 4 (+ 3 (+ 1 2)))
09:24	kogu	btw, anyone using clojure-mode on emacs here? how to see which parens does the parens under the cursor match to?
09:24	hoeck	kogu: i recommend the http://clojure.org/sequences page for an overview over the sequence library, though you may just use (doc reduce) at the repl
09:25	kogu	will read it, right now
09:25	Chousuke	but of course works with any function
09:25	Chousuke	for example, to find the max value of a sequence: (reduce #(if (< %1 %2) %2 %1)) []
09:26	Chousuke	oopw
09:26	Chousuke	well something like that
09:26	jdz	kogu: that's an emacs configuration option, "paren match highlighting" in options menu
09:26	Chousuke	does anyone know how to make emacs emit only spaces instead of tabs?
09:26	Chousuke	I noticed mine emits tabs and that screw up formatting sometimes.
09:27	jdz	Chousuke: indent-tabs-mode
09:27	jdz	(set it to nil ;)
09:27	hoeck	(setq-default indent-tabs-mode nil)
09:27	hoeck	but mine is an xemacs
09:27	jdz	yes, M-x customize-variable intent-tabs-mode
09:29	Chousuke	the customisation facilities in emacs are awesome
09:30	Chousuke	maybe a bit too awesome
09:30	Chousuke	there's so much to customise it can be difficult to find the relevant stuff
09:31	hoeck	but you can do <tab> and look at the autocomplete buffer
09:32	hoeck	i whish i could do this in the crappy powerbuilder ide i have to use at work :(
09:36	klinkers	nice
09:36	bOR_	Hi rhickey, working on a reproducable version that doesn't take 3 hours on 8 cores :)
09:37	bOR_	posted the source online.
09:38	klinkers	when will v1.0 of clojure come out?
09:38	bOR_	as long as none of you here are in the competitive field of doomsaying, I shouldn't get into trouble of sharing it here.
09:40	hoeck	klinkers: http://groups.google.com/group/clojure/browse_thread/thread/381e575bad1cfb77
10:00	rhickey	bOR_: I put up a rev that might help your problem - I think once you started failing you might have quickly wrapped the timestamp - now an AtomicLong in svn 1181
10:01	bOR_	thanks.
10:01	bOR_	not sure I understand.
10:01	bOR_	what you mean with wrapped the timestamp / now an AtomicLong.
10:02	kogu	rhickey : thank you for clojure
10:02	rhickey	bOR_: was an AtomicInteger - but once you started failing and let the sim continue you'd consume timestamps at a high rate
10:02	rhickey	kogu: you're welcome!
10:02	bOR_	ok.
10:03	bOR_	the high rate was 1.8 seconds? ("Elapsed time: 1871.911 msecs" )
10:05	rhickey	bOR_: that would explain your locked up situation afterwards, but you probably still have some bad transaction granularity.
10:06	bOR_	hehe. getting something to run concurrent in clojure is easier than understanding all the things that go wrong. Reading up on transaction granularity now. I'll just see if I can make a version of the model that quickly produces the error.
10:09	bOR_	I'll see if I can reduce it somehow.
10:11	bOR_	from birth: (let [living (apply vector (gather :born))
10:11	bOR_	ah.
10:11	rhickey	right
10:11	bOR_	birth is doing a gather of all living.
10:11	bOR_	and gather will be locking the whole thing.
10:11	rhickey	that's the gather I saw
10:11	bOR_	the rest almost only messes with a single ref.
10:12	rhickey	bOR_: it won't be locking, as it is only a read, but it will increase the footprint of the world snapshot required for that dosync
10:13	bOR_	ah.
10:14	bOR_	but if that is just a memory thing, I seem to have enough memory.
10:14	bOR_	for a moment thought it would be locking, but it is indeed only reading, and using a snapshot of what once was a father ;)
10:16	bOR_	at most I'm doing 8 births at the same time in the whole population. that doesn't seem too bad.
10:16	bOR_	(8 processors)
10:27	klinkers	how can i remove a namespace from the repl?
10:28	hoeck	(doc remove-ns)
10:28	klinkers	and how do I require my user-file? do i have to put it in a namespace?
10:29	klinkers	but the repl still says the old namespace...
10:35	kogu	what's the opp of "nil?"
10:37	Chouser	kogu: depends, but generally 'seq' or just the object itself
10:37	Chouser	s/generally/usually/
10:39	kogu	cho: its a number, hmmm
10:39	kogu	(defn eval-roll [roll]
10:39	kogu	(let [payout (odds roll)]
10:39	kogu	(if (nil? payout) -1 (- payout 1)))
10:39	kogu	where "odds" is a map
10:39	Chouser	you want to know if the map is empty?
10:40	Chousuke	payout is a number?
10:40	kogu	no, if i don't know have the key in the "odds" map, i get back null, which throws nullpointer
10:40	kogu	in if(payout)
10:40	Chousuke	kogu: you could use (get odds roll 0)
10:40	Chousuke	for a default value
10:40	Chouser	right, or just (odds roll 0)
10:43	kogu	(defn eval-roll [roll]
10:43	kogu	(let [payout (odds roll 0)]
10:43	kogu	(if (payout) -1 (- payout 1))))
10:43	Chouser	no
10:43	Chouser	(defn eval-roll [roll] (- (odds roll 0) 1))
10:44	kogu	yeah, that makes more sense
10:44	kogu	ty again
10:44	Chouser	but in the general case of wanting to handle a failed lookup separately, by default map lookups return 'nil', which in an 'if' means the same as false.
10:45	Chouser	so: (let [payout (odds roll)] (if payout (- payout 1) -1))
10:45	Chousuke	note no parentheses around payout. :)
10:45	kogu	ah, that was where i was stuck
10:45	Chouser	or: (if-let [payout (odds roll)] (- payout 1) -1)
10:47	kogu	cho: final question for you, I have a list of 2 random numbers, i have a odds table like this
10:47	kogu	(def odds {'(5 5 5) 25 '(4 4 4) 5 '(3 3 3) 5 '(2 2 2) 5 '(1 1 1) 5 '(0 0 0) 5})
10:48	kogu	now i need to check if i have 2 zeros 1 non zero
10:48	kogu	what would be the lispy way todo this
10:49	kogu	as i need to check for (0 0 ) (0 0) and (0 0 *)
10:49	Chouser	you have a list of 3 numbers?
10:49	kogu	yes, i have a list of 3 numbers (0-5 0-5 0-5)
10:50	kogu	for checking 3 numbers i made a map above
10:50	Chousuke	(= 2 (count (filter zero? triple))
10:50	Chousuke	)
10:51	Chouser	though I had: (= '(0 0) (filter zero? triple))
10:52	kogu	yes, that works perfectly
10:53	kogu	infact thats a better approach than the map for the 3 identical values
10:53	kogu	ty again
10:54	kogu	any fucntion to check if all values are identical?
10:54	Chouser	(apply = coll)
10:55	Chousuke	heh.
10:57	Chousuke	many of these solutions have the "d'oh" look to the
10:57	Chousuke	tem
10:57	Chousuke	...
10:57	Chousuke	them
10:57	kogu	(defn eval-roll [roll]
10:57	kogu	(cond
10:57	kogu	(apply = roll) 25
10:57	kogu	(= 2 (count (filter zero? roll))) 10
10:57	kogu	(= 1 (count (filter zero? roll))) 1
10:57	kogu	() -1))
10:57	kogu	how does this look
10:57	kogu	i think im done
10:58	Chouser	use :else instead of ()
10:58	kogu	done
10:58	kogu	time to benchmark against the java code, woohoo!!!
10:59	Chouser	you're sure it matters?
10:59	Chousuke	kogu: most likely it'll be a fair bit slower :)
11:00	Chouser	the most important benchmark is LOC, or some more reliable measure of mental complexity.
11:00	Chousuke	benchmarking might make java look good but does the code look as good as the clojure equivalent?
11:00	Chousuke	or "equivalent" :/
11:02	kogu	loc : 18 vs 57
11:02	Chouser	I wonder if condp would help here. I have no sense of how to use its features yet.
11:02	Chouser	kogu: ah, nice. That's worht so much more than 5 seconds vs. 1 second of processing time, or whatever.
11:03	kogu	speed : 7 sec vs 2, that's not bad
11:03	kogu	cho: ty again, you are truly awesome
11:04	Chouser	you could get back some or all of that speed, but it would start to cost you in code clarity
11:06	danm_	good morning
11:08	kogu	gm
11:15	kogu	any recommended profilers for clojure?
11:44	RSchulz	YourKit is what I use, though I've yet to apply it to Clojure code.
11:44	RSchulz	kogu: ^^^
11:44	kogu	rs: ty
11:45	kogu	does anyone of anywork on something like jsp's for clojure?
11:45	kogu	as in, compile to servlets
11:46	duck1123	kogu: there's been varying amounts of success with compojure
11:46	kogu	i did look into compojure, but right now there is no mention of any templating system
11:46	kogu	its much better to write html and embedd lisp rather than the other way around
11:47	duck1123	it uses compojure.html to generate html from vectors
11:48	kogu	duck: yeah, but i would like to write html file, and embedd bits of lisp in it
11:48	duck1123	There was a thread recently on that subject, I don't know how far anyone got
11:49	kogu	cool, let me dig that up
11:49	hiredman	ugh
11:49	hiredman	why would you want to write any html at all?
11:50	kogu	hehe, work!!!
11:51	kogu	is jvm good for anything else?
11:51	Chousuke	s-expressions map nicely to HTML anyway
11:51	qebab	hey, is it possible to use keyword params or optional params?
11:53	duck1123	kogu: http://tinyurl.com/7vlcj6
11:53	kogu	step 1: download free html template
11:53	kogu	step 2: write clojure blogging system
11:53	kogu	step 3: ???
11:53	kogu	step 4: profit!!!
11:53	hiredman	sounds horrible :(
11:54	Chouser	qebab: http://groups.google.com/group/clojure/msg/51bb53ca077154f8
11:54	hiredman	compojure's vector -> html deal is great
11:55	Chouser	qebab: that's some old code, so it could probably be written more concisely now. But at first glance it looks like it would still work.
11:58	qebab	Chouser: I don't really need it, I just think it'd be convenient. :)
11:58	qebab	Chouser: Thanks, though.
11:58	Chouser	if you just want some keyword args tacked on the end of zero or more positional args, you can do it in about one line
12:02	Chouser	(defn foo [a b c & keyargs] (let [{:keys [d e f]} (apply hash-map keyargs)] [a b c d e f]))
12:02	Chouser	(foo 1 2 3 :e 9) ==> [1 2 3 nil 9 nil]
12:39	daswerth	Chouser: yesterday you wrote up something on unbuffered input to a text terminal: http://paste.lisp.org/display/72515
12:39	Chouser	yep
12:40	daswerth	I'm afraid I don't understand why there are to defn's for "system"?
12:40	Chouser	just a pasting mistake on my part. The first is overridden by the second.
12:41	Chouser	as in, replaced. The first is completely unnecessary.
12:41	daswerth	ah, great. :)
13:30	klinkers	booya clojure is awesome
13:30	zakwilson	We've noticed. That's why we're here.
13:30	klinkers	a nice fairly pure functional language + a lot of good javalibs
13:31	klinkers	anyone working on machine learning stuff?
13:31	Chouser	people seem to ask about genetic programming a lot
13:31	klinkers	i working on webapp/mobile app using machine elarning for secret stuff and great profits!
13:32	klinkers	maybe i will eb the first big clojure success story
13:33	Kerris7	I've been tinkering with the idea of writing a Chinese Chess a.i. in Clojure
13:34	Kerris7	should make for a decent final year project, but the other candidates are quite strong (Scala)
13:36	klinkers	final year of what?
13:37	klinkers	undergrad?
13:37	klinkers	i wrote an optimal-playing tictactoe in clojure but chinese chess is a little harder :)
13:38	Kerris7	klinkers: undergrad
13:43	Kerris7	klinkers: yes, a little harder :P http://en.wikipedia.org/wiki/Xiangqi
13:44	Chouser	Kerris7: I was learning Scala before I abandoned it for Clojure, in case that's worth anything to you.
13:45	Kerris7	Chouser: I'm working on a portfolio that'll hopefully admit me to a good Master program and the existing material for that domain is mainly in OCaml
13:46	Chouser	Kerris7: ah. sounds like you may have significantly different goals than I had.
13:46	Kerris7	Chouser: if you don't mind me prying, what were your intentions?
13:46	Chouser	for a masters program, Clojure's non-invasive type system may look less impressive.
13:48	Chouser	Kerris7: For years I'd been looking for a practical language that was very "expressive", or at least that's the term I generally use.
13:50	Kerris7	alright
13:50	Chouser	...which means something along the lines of getting the most done with the least amount of code, where the things being done are the sorts of things python and ruby have been good at: command-line tools, data and string wrangling, web apps, etc.
13:50	gnuvince	Hehe
13:50	technomancy	heh; I guess for education purposes, Scala has the advantage of looking more impressive since the type system is harder to use. =)
13:50	Chouser	technomancy: exactly what I was thinking.
13:50	gnuvince	"Dude, Clojure is too easy, no way you're getting that Masters Degree!"
13:51	gnuvince	Throw in partial continuations and amb in there to make it look more impressive
13:51	Chouser	I was skating through project euler problems in Scala, liking it just fine.
13:52	Chouser	Then I tried to write a nice API (a.k.a. embedded DSL) for querying XML documents.
13:52	gnuvince	Didn't like it so much then?
13:52	Chouser	the type system bit me hard. I was trying to use the code as I wrote it to help me think about the problem. When I got it into a state that seemed to express what I wanted, I still couldn't test it because my types were all messed up.
13:53	Chouser	I spent a few days trying to get my trivial 4 or 5 function system to actually compile.
13:54	Chouser	and even then the lack of macros meant my API wasn't as tidy as I wanted.
13:54	Kerris7	If I can find sufficient material on writing lexers with Lisp maybe I can muster up something with Clojure
13:55	Chouser	Anyway, a couple rhickey videos later, and I'd found a new home here. The result a similar project in Clojure is at clojure.contrib.zip-filter
13:56	gnuvince	Chouser: are you a Java refugiee?
13:56	Chouser	not really. I learned Java a tiny bit ages ago -- actually learned threading in Java -- but I've never liked it much.
13:57	gnuvince	ok
13:57	gnuvince	I'm thinking I should probably learn Java
13:58	Chouser	I was giving the JVM a chance because Yegge talked me into Rhino, shortly before Project Euler talked me right back out of it.
13:58	gnuvince	Rhino...
13:58	gnuvince	meh
13:59	Chouser	Well, I thought I wanted an optional type system and C-like syntax.
13:59	gnuvince	Is there a Java library to do like Python's struct.pack and struct.unpack?
13:59	technomancy	the way they promoted it early on was pretty weird--hey guys, you can use all these awesome Java libraries and package stuff up as a WAR file.
13:59	gnuvince	Nobody really wants C-like syntax; people just think they want it.
13:59	Chouser	gnuvince: for C library interop, or more general binary data packing?
13:59	technomancy	and Ruby users look at the Java libs, and they have uniformly horrible APIs... and we have no idea what a WAR is, but it sounds violent.
14:00	technomancy	so it was hard to get excited about JRuby at first. =)
14:00	hiredman	technomancy: but uniformly documented
14:00	gnuvince	Chouser: general binary data unpacking
14:01	Chouser	gnuvince: ah, don't know. sorry.
14:01	technomancy	hiredman: you only have to learn a library once; you have to deal with the API forever. =)
14:01	gnuvince	Chouser: thanks
14:01	hiredman	technomancy: you just deal with the api long enough to wrap it with something more sane
14:02	hiredman	javadoc is a life saver
14:02	technomancy	well, the only Java libraries I've used have been jakarta httpclient (wretched, horrible API) and ROME (decently usable, but the docs weren't very good)
14:03	technomancy	why you'd name a library after Jakarta is beyond me; I've been there, and it's a pretty miserable city.
14:04	hiredman	maybe that is why they renamed it to apache commons
14:04	Kerris7	maybe it was mainly developed by programmers from the city :V
14:06	leafw	likely it was chosen beause of the 'j' in the name.
14:06	hiredman	heh
14:06	lisppaste8	drewr pasted "atom exception -- how is this possible?" at http://paste.lisp.org/display/72540
14:06	technomancy	leafw: probably. It's a good warning for what happens when you pick a name without doing research first.
14:07	drewr	I think there's either a bug in atom or swap!.
14:07	hiredman	someone in #java just asked about a "macro system" for java, and someone said "macros are for desktop apps like word and excel or for editors."
14:07	drewr	Somehow iref is nil in get-validator.
14:07	Chouser	drewr: got any code to reproduce it?
14:08	technomancy	heh
14:08	leafw	hiredman: difficult to preach to the blind.
14:08	Kerris7	or the deaf
14:08	drewr	Chouser: I'm trying to distill. My smaller test cases aren't triggering it.
14:08	Chouser	drewr: are you using validators?
14:08	drewr	I thought I would start with the exception first, because it's pretty strange.
14:10	Chouser	drewr: I can replicate the top 3 lines of that stack trace with: (swap! nil inc)
14:11	lisppaste8	drewr annotated #72540 with "possible sample code" at http://paste.lisp.org/display/72540#1
14:13	Chouser	drewr: so if your agent's map ever loses its :foo key, you'd get that exception.
14:14	drewr	Chouser: I'm trying to see if that happens.
14:15	drewr	Dangit, it's nil. This thing is supposed to be immutable! :-)
14:17	Chouser	hm, the agent? not likely. :-)
14:17	technomancy	has anyone here tried hashdot? (http://hashdot.sf.net) it seems to make the JVM CLI experience somewhat less onerous.
14:17	drewr	Chouser: No, the map :-)
14:41	gnuvince	How come (reduce str xs) is so much slower than (apply str xs)?
14:42	hiredman	str makes stringbuilders I believe
14:43	hiredman	so reduce ends up instanciating a lot more objects
14:45	gnuvince	How does apply avoid that?
14:48	rhickey	gnuvince: a single call to str creates one StringBuilder, and apply is a single call to str
14:48	rhickey	reduce is many calls to str
14:50	gnuvince	apply creates a single StringBuilder and calls .add() (or whatever the name is) n times while reduce creates n StringBuilders and calls .add() only once on those?
14:52	rhickey	gnuvince: it's best to forget about str - apply calls a fn once with a sequence of args, reduce calls it once for each pair of elements. str optimizes the concatenation of its args, but can't across calls
14:55	gnuvince	ok
14:55	hiredman	the "namespaces, keywords, and symbols" looks like it might need a faq entry
14:57	duck1123	Does anyone know if a SVG version of the clojure logo exists?
14:58	RSchulz	hiredman: Whatever makes you think that??
15:01	hiredman	:P
15:16	hoeck	duck1123: clojure-glyph.svg in the files section of the google group
15:21	Chouser	it only seems complicated if you try to think about it
15:22	hiredman	Chouser:?
15:22	Chouser	namespaces, vars, symbols, keywords. They all work very naturally almost all the time.
15:23	hiredman	yes
15:23	hiredman	I don't mean it is complicated, I mean there are two different threads in group about it, so maybe it is a faq
15:23	Chouser	it's only when you try to think about edge cases or unusualy usages that it starts to seem complicated.
15:23	Chouser	oh
15:27	Chouser	it does seem a bit hard to pin down what should go in a faq vs. an appropriate place in the regular docs.
15:29	hiredman	well
15:29	hiredman	things that are asked about frequently can go in the faq?
15:29	Chouser	if the docs were complete, would they still be asked about frequently?
15:30	hiredman	the only way to find out is to complete the docs
15:30	Chouser	if I want to learn about topic X, do I need to read it's section in the regular docs plus in the FAQ in order to get a complete picture?
15:32	hiredman	if the docs clear it up, and people stop asking about it, it can be removed from the faq
15:32	hiredman	it's not like this is being carved in stone, it's html
15:38	technomancy	is it safe to say atoms are meant for idempotent actions?
15:40	Chouser	not necessarily.
15:41	Chouser	Someone mentioned on the group the function of generating unique ids, where skipping an id is acceptible. atom would work fine for that.
15:42	technomancy	that makes sense
15:47	klinkers	if i have a file main that uses the namespace progs.someapp.donkey and progs.someapp.horse and they both happen to have a function group-by. now, how do i refer to each group-by in main?
15:49	Chouser	if you try to (use ...) both of them, it should complain on the second one.
15:52	Chouser	klinkers: so you can either do (use '[progs.someapp.horse :rename {group-by horse-group-by}])
15:53	Chouser	or (require '[progs.someapp.horse :as horse]) and say (horse/group-by ...)
16:47	hiredman	why don't explanations of what a monad is make sense?
17:04	Chousuke	hiredman: actually, reading through the wikipedia explanation I think I can see some sense in it.
17:05	hiredman	then you are a better man than I
17:06	Chousuke	hiredman: it seems monads can be used to specify semantics to computations without affecting the "functional" nature of the values those computations return
17:06	hiredman	woosh
17:07	Chousuke	I think the Maybe monad is pretty simple to understand: the computation can fail, so the Maybe monad wraps the value in something that can tell you whether it failed or not.
17:07	amit_	any idea why i might get an IllegalAccessError trying to invoke a constructor for a java class even though I'm able to import it succesfully ? (I'm on the clojure prompt)
17:08	Chousuke	but if it doesn't fail, the result is safe to extract from the monad and treat as if it were just another value
17:08	hiredman	sounds like Just Another Object
17:11	Chousuke	for IO I guess the IO monad "describes" the IO required to get the value (a string, for example), but once you have the value and have extracted it from the monad, it's immutable just like any other value
17:11	Chousuke	so monads give you a way to explicitly define that something else than just functional value computation is going on, and work with that.
17:12	hiredman	uh huh
17:50	drewr	Is there any way I can get @@(send-off (agent :a) (fn [x] (send-off (agent :b) (fn [y] y)))) to work?
17:50	drewr	Work == return :b immediately.
17:52	Chouser	you want the top-level expression to not return until both agents have updated their status?
17:53	Chouser	s/status/state/
17:53	drewr	Yes, that would be ideal.
17:54	Chouser	using agents synchronously like this is a bit non-idiomatic (are you sure you don't want refs?) which costs you some complexity, but it can be done.
17:54	drewr	In my use case, :a is a long-running thread which fires b's off periodically. What happens is b agents are return immediately, but their actions aren't fired until what seems like too late.
17:55	Chouser	'sends' done in an agent's action are held until the action is complete. this is a feature.
17:56	Chouser	agent :a is in some kind of loop, but not sending to itself?
17:57	drewr	Yes, :a is doing something similar to (loop [] (something-that-eventually-fires-b) (Thread/sleep ...) (recur)).
17:58	Chouser	it might help to (send agent thisfn) instead of recur. That will allow other sends to go as well.
17:59	drewr	You mean recurse by creating another agent?
17:59	hiredman	this might also be faq worthy
17:59	Chouser	drewr: no, recurse by sending to your own agent again
18:00	hiredman	agent is bound to the current agent inside an agent action
18:00	Chouser	drewr: this is how at least one of the agents behaves in Rich's ant demo
18:00	drewr	Ah. Hm, let me look at that.
18:02	hiredman	man, I miss clojurebot
18:02	hiredman	it's like phantom limb
18:02	drewr	OK, (send-off agent #'behave).
18:04	hiredman	clojurebot: FAQ#2 is sends and send-offs that occur in an action sent to an agent do not take place until the agent's state changes
18:05	Chouser	drewr: right, though there's no need for the #' prefix anymore
18:06	Chousuke	hiredman: talking to ghosts now? where is clojurebot, anyway?
18:06	hiredman	hard drive died, so I need to rebuild the machine
18:06	Chousuke	ah.
18:06	drewr	Chouser: So send* won't consume the stack?
18:07	drewr	It will just fire off new threads and the old ones gc?
18:07	Chouser	(send (agent 9) (fn act [v] (prn v) (when (pos? v) (send agent act) (dec v))))
18:07	hiredman	cute
18:08	Chouser	drewr: even better, it will probably return the current thread to the pool before the new one is needed, so it may even use the same thread.
18:08	Chouser	but yes, no consumption of finite resources
18:10	Chouser	interesting -- using 'send' on this dual-core laptop, the action is indeed run on the same thread each time.
18:10	drewr	Sweet.
18:11	Chouser	using 'send-off' it oscilates between two threads.
18:11	Chouser	I wouldn't bet too heavily on either behavior in any given circumstance, of course.
18:12	Chouser	drewr: so that'll get your sends to agent :b going periodically. you still need the top-level thread to wait until they're all done?
18:13	drewr	In this case, :b is a network connection, and :a watches to see if any die and restarts them.
18:14	drewr	Starting works great, but the restarts involve the nested agent issue.
18:14	Chouser	sure.
18:14	drewr	Each connection has a listener agent which is another long-running loop that's doing (read-line) on the input stream.
18:15	drewr	These listener agents (and their associated async msg queues) don't ever have their actions fired.
18:15	drewr	Presumably that's because of my infintely loop-recurs that don't return.
18:16	Chouser	right. another benefit of the re-send looping is you can swap in a new definition of your function at runtime and the next send will pick it up.
18:16	drewr	Ah, yes.
18:24	drewr	So in (send agent foo), does the arg to foo become the future state of the first run through foo?
18:25	Chouser	no, the return value of the action becomes the new state of the agent.
18:25	Chouser	in that little example I posted above, I did the (dec v) after the (send ...)
18:26	drewr	That's what I was basing that on. I think you said what I meant by my question.
18:26	drewr	Just didn't express it clearly.
18:26	Chouser	:-) ok
18:54	arohner	I'm trying to read out of a socket, and BufferedReader.read() wants a buffer to fill up. What is the easiest way to create a buffer from clojure?
18:56	Chouser	you want the classic char[] variety?
18:56	arohner	ah, make-array
18:56	arohner	Chouser: yes
18:56	Chouser	right, (make-array Character/TYPE 1024)
18:57	arohner	thanks
21:28	arohner	(java.util.regex.Pattern/matches "(.+): (.+)" "Host: localhost:1344")
21:28	arohner	true
21:29	arohner	user> (. #"(.+): (.+)" (split "Host: localhost:1344"))
21:29	arohner	#<String[] [Ljava.lang.String;@19ad02>
21:29	arohner	user> (alength (. #"(.+): (.+)" (split "Host: localhost:1344")))
21:29	arohner	0
21:29	arohner	That is completely unhelpful
21:29	arohner	matches with zero length?
21:35	Chouser	(re-seq #"(.+): (.+)" "Host: localhost:1344")
21:36	Chouser	the regex matches the entire string, so it's a match and you get an array
21:36	Chouser	but the contents of the array are the pieces of the string separated by what matched -- which is nothing.
21:39	arohner	oh, I needed to use re-matches
22:07	pjb3	Hey, I have a solution for Paul Graham
22:07	pjb3	's Accumulator Generator in Clojure: http://github.com/pjb3/accgen/tree/master/accgen.clj
22:07	pjb3	This seems pretty good, any ideas on how to do it differently?
22:08	hiredman	lisppaste8: url?
22:08	lisppaste8	To use the lisppaste bot, visit http://paste.lisp.org/new/clojure and enter your paste.
22:10	hiredman	pjb3: http://paste.lisp.org/display/70873
22:11	pjb3	hiredman: huh?
22:11	hiredman	its a counter
22:12	pjb3	The problem: Write a function foo that takes a number n and returns a function that takes a number i, and returns n incremented by i.
22:12	hiredman	so how c works is
22:12	hiredman	(c 3) returns a function
22:13	hiredman	which returns a function, etc
22:13	hiredman	until you pass the function something not a number
22:13	hiredman	at which point it tells you how many times you called the function
22:13	pjb3	hiredman: well, that's nice, but I don't see how that's a solution to the problem
22:14	hiredman	it is a subset of the problem, the case where you increment by 1
22:15	hiredman	anyway
22:16	pjb3	hiredman: It's a solution to a different problem
22:16	hiredman	I did not read the problem, I just saw "Accumulator Generator"
22:16	pjb3	(let [acc (foo 1)] (acc 20) (acc 21))
22:16	pjb3	should be 42
22:17	pjb3	I think the original intent of the problem is basically a test to see "does your language have closures and lambas"
22:17	pjb3	Which PG considers to be important things
22:18	pjb3	but the other thing you need is mutable state
22:19	pjb3	This works pretty much the same way, except you have to give the function access to the atom as a closure
22:33	doublefree	Hi all, I'm new to Clojure, and I wonder what is a fast way to select a (or n) random element(s) from a potentially large set?
22:35	doublefree	I'd like to avoid converting the set to a vector if possible
22:40	pjb3	doublefree: Off the top of my head, I don't know of a way to do that without converting it to a vector
22:42	doublefree	pjb3: ok - perhaps it is my data's destiny to live in a vector after all
22:42	pjb3	doublefree: Does this help? http://stackoverflow.com/questions/124671/picking-a-random-element-from-a-set
22:47	doublefree	I see the proposed Lisp solution there reflects my initial approach (the following doesn't work because PersistentHashSet does not support nth which makes sense I suppose): (defn pick-random [set] (nth set (random (count set))))
22:47	pjb3	huh, sets aren't seqs?
22:48	pjb3	doublefree: Yeah, I was just trying that, but ran into sets not being a seq
22:49	hiredman	nothing is it's own seq except lists
22:49	hiredman	but seq knows how to turn sets into seqs
22:49	hiredman	user=> (seq #{:a :b :C})
22:49	hiredman	(:b :a :C)
22:50	pjb3	(defn pick-random [set] (let [sq (seq set)] (nth sq (rand-int (count sq)))))
22:53	doublefree	pjb3: thanks works well enough for now!
22:53	pjb3	doublefree: yeah, not sure if that's "fast"
22:53	pjb3	is (seq #{...}) O(n)?
22:54	pjb3	Or is there some fast way under the covers of making a lazy-seq from a set
22:55	pjb3	clojurebot: ?
22:56	hiredman	I have the new hard drives for the clojurebot machine
22:56	hiredman	so it will be back soon
22:56	pjb3	anyway, the docs for nth say it takes a coll, and the docs for sets says it is a collection
22:57	pjb3	Right, and (coll? #{}) is true
22:57	pjb3	so, that's a little confusing
22:59	hiredman	maybe something to mention to rhickey
23:08	Chouser	almost none of the collections are seqs, but all provide efficient (generally lazy) seqs when you pass them to seq
23:09	Chouser	nth doesn't work on all collections, and unlike some functions doesn't apply seq to its parameter
23:09	hiredman	yeah I just looking at the source in google code
23:09	drewr	I changed some sends I had to send-off and certain things started working and I have no idea why.
23:10	hiredman	maybe it should say "only works on certain collections"
23:10	hiredman	I take that back
23:10	hiredman	the doc string doesn't say it takes collections
23:10	hiredman	don't know why I thought it did
23:11	Chouser	it uses 'coll' as the arg name
23:11	hiredman	short for collar of course
23:47	doublefree	I find it strange that (first #{1 2}) and (second #{1 2}) work while (nth #{1 2} 0) does not... I see first and second call seq on their args, and apparently nth does not. I wonder why this is.
23:47	Chouser	nth can't be any faster that O(n) on a seq
23:47	Chouser	but it it works in O(1) time on vectors, array, etc.
23:53	doublefree	yes, but nth could seq its arg if it's not of a class that provides constant time lookup itself and in doing so provide a more consistent interface. anyways no biggy.