#clojure – 2009-01-16

2009-01-16

00:22	durka	is it possible to define a lazy seq that is reified 100 elements at a time
00:22	durka	i suppose i could just use flatten
00:32	durka	so given that the namespaces a.b.c and a.b.d exist, and a.b.c/f and a.b.d/g are functions in them
00:32	durka	i sort of want to do this
00:33	durka	(use 'a.b)
00:33	durka	(c/f "blah") (d/g "quux")
00:33	durka	but it doesn't work
00:34	durka	is there a way to do that kind of thing?
00:37	Chouser	(require '[a.b.c :as c] '[a.b.d :as d]
00:37	Chouser	)
00:37	Chouser	I think.
00:38	Chouser	or even: (require '(a.b [c :as c] [d :as d]))
00:38	durka	thanks
03:38	sleven	why is it much faster to write to Derby than to postgresql?
04:58	timothypratley	In Rich's ants.clj there is a global 'running', how does this get set to false? [is it ever?]
05:01	hiredman	it would have to be a binding, a set!, or a def
05:01	hiredman	I have not looked at ants.clj, but maybe running is a flag, and if you set it to false the simulation stops
05:02	timothypratley	http://clojure.googlegroups.com/web/ants.clj
05:02	timothypratley	yeah that's what I thought,
05:02	timothypratley	except it never gets set to false
05:02	hiredman	I imagine you would set it to nil in the repl
05:03	timothypratley	ah :)
12:34	danlarkin	this is a goof, http://kiwi.cabal.fi/home/aki/misc/cons-ceremony.txt
12:41	durka	heh
12:41	durka	bit of a verbose trace there
13:20	Lau_of_DK	Good evening all
13:23	cgrand	evening, Lau!
13:23	durka	good afternoon
13:23	Lau_of_DK	;)
13:49	clojurebot	svn rev 1216; lift loops from expression contexts
14:03	kefka	I'm using Svn rev 1178. I do not have gen-and-save-class. Do I need a newer version of Clojure?
14:06	danlarkin	kefka: why not update anyway, you'll get lots of bug fixes :)
14:06	hiredman	the gen-and-save stuff is mostly gone
14:06	danlarkin	regarding your question, though, gen-and-save-class is old school
14:06	hiredman	a lot of changes in those areas
14:07	kefka	Ok, so gen-and-save-class is outdated? What do I do if I want to generate a .class file on the fly?
14:07	hiredman	,(doc compile)
14:07	clojurebot	------------------------- clojure.core/compile ([lib]) Compiles the namespace named by the symbol lib into a set of classfiles. The source for the lib must be in a proper classpath-relative directory. The output files will go into the directory specified by compile-path, and that directory too must be in the classpath.
14:07	hiredman	er
14:08	hiredman	kefka: you should avoid generating .class files on the fly
14:10	kefka	hiredman: Ok. So what are current best practices for generating a standalone executable?
14:10	hiredman	what are you doing that requires it?
14:10	hiredman	clojurebot: stand alone?
14:10	clojurebot	Excuse me?
14:10	kefka	I'm sending an executable to a remote machine that has the JVM but not a Clojure intrepreter.
14:10	hiredman	kefka: well, you will need the clojure.jar regardless
14:11	clows	that clojurebot doc just made me realize what i did wrong with gen-class :)
14:11	hiredman	the class clojure generates are just stubs that call to clojure
14:15	clows	if I wanted to subclass a swing class and use that in clojure (and also call methods of that subclass form clojure). would using gen-class allow me do to that?
14:16	Chousuke	gen-class or proxy perhaps
14:16	hiredman	clows: I would look at proxy
14:17	clows	I tried proxy first but i can't seem to be able to access the added methods
14:17	hiredman	proxy does 90% of what people want from gen-class and does it with less fuss and muss
14:17	hiredman	oh
14:17	hiredman	yeah
14:17	clows	might be my fault ofc
14:17	hiredman	nah
14:17	hiredman	proxy doesn't let you add methods
14:17	hiredman	that is right, for subclassing you still want gen-class
14:17	clows	ok
14:18	hiredman	clojurebot: gen-class?
14:18	clojurebot	No, hiredman, you want gen-interface + proxy
14:18	clows	I'm thinking just doing that stuff in java might be the best way to go anyway ... it kinda gets messy in clojure
14:18	Chousuke	AFAIK if you only need to override superclass methods then proxy works. otherwise you need gen-class
14:19	clows	that'd explain i think
14:20	hiredman	http://clojure.org/compilation <-
14:22	hiredman	http://gist.github.com/34229 <-- nasty bean maker macros using gen-class
14:23	hiredman	hmm
14:23	clows	I struggled with gen-class because i didn't have the right classpath ... meh ... but it seems to work now. thats a start :)
14:26	Chousuke	gen-class is a lot easier to use now than it used to be though :P
14:28	clows	it seems easy enough. once you read about compile-path ...
14:31	Chouser_	one thing to keep in mind is that lots of stuff that in Java would require a subclass with new methods or data members can be done in Clojure with proxy and closures.
14:32	Chouser_	If you really truly need new methods, then you will have to compile something (gen-class or gen-interface)
14:33	Lau_of_DK	Chouser_: Why isnt your nick verified?
14:33	Lau_of_DK	registered
14:50	pjb3	I'd like to have a ref that contains a vector
14:50	pjb3	and have some way to call a function like take on it
14:50	pjb3	where it returns n items from the vector, but also removes them from the vector in the ref
14:51	pjb3	but obviously in a safe way, so if there are multiple threads pulling stuff from the ref, things don't get taken twice by different threads
14:51	pjb3	does that make sense? ideas?
14:51	pjb3	Is there a name for that kind of pattern?
14:52	durka	that's a transaction isn't it
14:53	pjb3	well, it would probably invlove a transaction
14:53	pjb3	but in thinking about it initially it's tricky because you want to modify what's in the collection
14:54	durka	(doc pop)
14:54	clojurebot	For a list or queue, returns a new list/queue without the first item, for a vector, returns a new vector without the last item. If the collection is empty, throws an exception. Note - not the same as rest/butlast.; arglists ([coll])
14:54	hiredman	pjb3: you want a write lock
14:54	hiredman	or whatever it is called you you block others from writing
14:54	pjb3	hiredman: yeah, but I thought the whole point of clojure was to avoid having to manage locks :)
14:55	pjb3	,(pop '(1 2 3))
14:55	clojurebot	(2 3)
14:55	hiredman	pjb3: depends
14:55	pjb3	see, but I need the 1 as well
14:55	hiredman	(doc peek)
14:55	clojurebot	For a list or queue, same as first, for a vector, same as, but much more efficient than, last. If the collection is empty, returns nil.; arglists ([coll])
14:55	pjb3	,(peek "xyz")
14:55	clojurebot	java.lang.ClassCastException: java.lang.String cannot be cast to clojure.lang.IPersistentStack
14:55	pjb3	,(peek [1 2 3])
14:55	clojurebot	3
14:56	hiredman	,(peek (seq "xyz"))
14:56	clojurebot	java.lang.ClassCastException: clojure.lang.StringSeq cannot be cast to clojure.lang.IPersistentStack
14:56	hiredman	I see
14:56	pjb3	,(peek '(1 2 3))
14:56	clojurebot	1
14:56	hiredman	actually
14:56	hiredman	yeah, transactions, thats the ticket
14:56	pjb3	What I want is:
14:57	pjb3	(def stuff (ref '(1 2 3)))
14:57	pjb3	(take-and-remove 2) => (1 2)
14:57	pjb3	@stuff => (3)
14:57	hiredman	so if you do the read and write in the same dosync block
14:58	hiredman	(same transaction)
14:58	pjb3	,(take 2 '(1 2 3 4 5))
14:58	clojurebot	(1 2)
14:59	pjb3	,(drop 2 '(1 2 3 4 5))
14:59	clojurebot	(3 4 5)
14:59	pjb3	ah, there it is, do that in a dosync
15:00	hiredman	(doc split-at)
15:00	clojurebot	Returns a vector of [(take n coll) (drop n coll)]; arglists ([n coll])
15:00	pjb3	,(split-at 2 '(1 2 3 4 5))
15:00	clojurebot	[(1 2) (3 4 5)]
15:01	durka	heh, the source of split-at is its docstring
15:01	Chousuke	:)
15:01	tomsw	Can anyone explain why I get a "method not found" error from java when I try this: (doto (javax.swing.JFrame.)
15:01	tomsw	(.setLayout (java.awt.GridLayout. 2 2 3 3)))?
15:02	tomsw	It's from http://en.wikibooks.org/wiki/Clojure_Programming/By_Example - I'm just trying to get the hang of things
15:02	hiredman	tomsw: $5 says you have an old version of clojure
15:02	hiredman	what is the exact message?
15:03	tomsw	hiredman: java.lang.IllegalArgumentException: No matching method found: .setLayout for class javax.swing.JFrame (NO_SOURCE_FILE:0)
15:04	hiredman	yeah
15:05	hiredman	you are using the new doto syntax with an old version of clojure
15:05	pjb3	I don't get an error when I run that, just seems to not really do aything
15:05	pjb3	other than return the JFrame
15:05	pjb3	oh yeah, that's probably it
15:05	durka	well it won't until you .show the JFrame
15:05	pjb3	(.show *1)
15:05	pjb3	and there it is :)
15:05	hiredman	you can tell because of the ".setLayout" the fact that it sees the "." in the method name
15:06	tomsw	hiredman: you mean it should be trying to call "setLayout" without the leading dot
15:06	hiredman	yes
15:06	hiredman	clojurebot: svn?
15:06	clojurebot	svn is http://clojure.googlecode.com/svn/trunk/
15:07	Chousuke	tomsw: download the newer release from google code, or get the latest SVN
15:07	tomsw	hiredman: thanks. I'll install it & pester you all with silly questions in a bit :)
15:07	Chousuke	clojurebot: download
15:07	clojurebot	download is http://code.google.com/p/clojure/downloads/list
15:14	Chouser_	pjb3: you have your transaction function worked out?
15:16	pjb3	Chouser_: Yeah, I haven't written it out yet, but it should just be (let [things (take n the-list)] (drop n the-list) things)
15:16	pjb3	how do I set the ref to the dropped version of the list?
15:17	hiredman	(doc alter)
15:17	clojurebot	Must be called in a transaction. Sets the in-transaction-value of ref to: (apply fun in-transaction-value-of-ref args) and returns the in-transaction-value of ref.; arglists ([ref fun & args])
15:18	Chouser_	(dosync (let [things (take n the-list)] (alter the-list drop n) things)) I think
15:19	pjb3	(def stuff (ref '(1 2 3 4 5 6 7 8 9)))
15:19	pjb3	(dosync (alter stuff drop 3))
15:19	pjb3	java.lang.ClassCastException: clojure.lang.PersistentList
15:19	pjb3	same for
15:19	pjb3	(dosync (alter @stuff drop 3))
15:19	Chouser_	ah, indeed. (alter stuff #(drop 3 %))
15:20	durka	(alter stuff (switch drop) 3)
15:20	durka	(defn switch [f] #(f %2 %1))
15:20	Chouser_	heh
15:20	durka	i find myself using that all the time
15:20	Chouser_	really? I just use #(foo arg %)
15:21	pjb3	What's the difference between alter and commute
15:21	pjb3	?
15:21	pjb3	(doc alter)
15:21	clojurebot	Must be called in a transaction. Sets the in-transaction-value of ref to: (apply fun in-transaction-value-of-ref args) and returns the in-transaction-value of ref.; arglists ([ref fun & args])
15:21	pjb3	(doc commute)
15:21	clojurebot	Must be called in a transaction. Sets the in-transaction-value of ref to: (apply fun in-transaction-value-of-ref args) and returns the in-transaction-value of ref. At the commit point of the transaction, sets the value of ref to be: (apply fun most-recently-committed-value-of-ref args) Thus fun should be commutative, or, failing that, you must accept last-one-in-wins behavior. commute allows for more c
15:22	pjb3	I guess commute is faster, so if your operation is communative, you would use that instead of alter?
15:22	clows	java.lang.NoSuchMethodError: clojure.lang.Util.equal ... has that method been renamed by any chance?
15:22	Chouser_	commute is to be used on commutative functions, alter for others
15:23	pjb3	I assume replacing the value of a ref with another value is not communative
15:23	pjb3	especailly in this case
15:23	pjb3	so alter is needed
15:23	durka	,(show clojure.lang.Util)
15:23	clojurebot	java.lang.Exception: Unable to resolve symbol: show in this context
15:23	durka	clows: there is a static equals method, is that it?
15:23	Chouser_	no, alter and commute are always for replacing the value of a ref with another. The difference is the function you pass to each of them.
15:24	Chouser_	I used 'alter' because it's safer. It takes thought to determine if 'commute' will be ok in a given situation.
15:24	pjb3	,(def x (ref 1))
15:24	clojurebot	DENIED
15:25	clows	dukra: yeah i think so
15:25	clows	I get this error message when trying to (load-file) my test file... java.lang.NoSuchMethodError: clojure.lang.Util.equal(Ljava/lang/Object;Ljava/lang/Object;)Z (internal.clj:26)
15:26	Chouser_	clows: you may need to do a clean and rebuild of clojure, those functions have changed recently.
15:26	pjb3	(def x (ref 1))
15:26	pjb3	(dosync (alter x inc))
15:26	clows	I thought I did but ... yeah will do again :)
15:26	pjb3	(dosync (commute x inc))
15:26	Chouser_	cleans are supposed to happen automatically now, but someone on the group said that fixed a similar problem for them.
15:27	pjb3	so both of those work, but in that case, you want to use commute, because the operation is communative
15:27	Chouser_	pjb3: the difference will only show up under contention, when two threads are in the transaction at the same time.
15:27	pjb3	I'm not sure I understand how to tell if my function is communative
15:27	Chouser_	for your 'drop' case, i'm pretty sure you need 'alter'
15:27	pjb3	Chouser_: yeah, I agree
15:28	pjb3	Or would you?
15:28	pjb3	Because if I have 2 threads that need to get 10 items from the list
15:28	pjb3	to work on
15:28	pjb3	they don't care which ones
15:28	durka	if you don't care which one gets in first...
15:28	durka	then it should be commutative
15:28	rhickey	pjb3: you must use alter
15:29	durka	i stand corrected
15:29	durka	what did i miss
15:29	pjb3	The thread doesn't care which items it gets, so shouldn't that be communative?
15:29	Chouser_	with commute, you may see a different value for the ref than will actually be committed.
15:29	rhickey	pjb3: it does care that it doesn't get he same items as another
15:30	pjb3	(dosync (let [items (take 5 stuff)] (comute stuff #(drop 5 %))))
15:30	clows	I think it's a clojure contrib issue (I might have to update that too) :)
15:30	pjb3	that's what we are talking about doing
15:30	Chouser_	In your case if you used commute, the list would always shrink by the right amount, but two threads may get overlapping values, and other may get skipped.
15:30	pjb3	rhickey: that is true
15:30	rhickey	pjb3: that's plainly read-modify-write, must be alter
15:31	pjb3	rhickey: Ok, I'll take your word for it, like you said yesterday, I obviously need to read Java Concurrency in Practice
15:31	rhickey	commute is for things like a tasks-done counter, each transaction wants to increment it, but doesn't care about specific before/after values
15:31	pjb3	so when doing alter
15:31	pjb3	with the dosync above
15:31	pjb3	or commute I mean
15:31	pjb3	in the case above
15:32	pjb3	if the transaction detects there is a conflict, it won't run the take again?
15:32	rhickey	pjb3: with commute there is never a conflict
15:32	rhickey	each transaction takes the at-commit time value and modifies it
15:33	rhickey	you need alter, gotta run...
15:33	pjb3	rhickey: thanks, I believe you, just trying to understand it better
15:34	Chouser_	pjb3: I believe the commutes will get queued up and applied again later.
15:36	pjb3	Chouser_: so what happens with alter?
15:37	Chouser_	with alter, if there's a conflict the whole transaction will be retried.
15:37	Chouser_	I think. :-)
15:37	pjb3	and what does "the whole transaction" mean?
15:37	Chouser_	The outermost enclosing dosync
15:37	pjb3	because I assume that means everything in the body of the dosync, right?
15:38	Chouser_	yes
15:38	pjb3	so if the ref has the numbers 1 - 9 in it
15:38	pjb3	then thread a starts the dosync from above
15:38	clows	(updating clojure-contrib fixed that btw .... I love it when i trip over my own feet)
15:38	pjb3	first is does take 3 on the ref
15:38	pjb3	which returns 1 2 3
15:38	pjb3	then thread b does take 3 on the same ref, also returning 1 2 3
15:39	pjb3	then thread a does the drop in the alter , which leaves 4 - 9 in the ref
15:39	pjb3	then thread b tries to do the the drop, which would also leave 4 - 9, but that's a conflict
15:40	pjb3	so then thread b should restart that dosync, do take 3 which this time returns 4 5 6, because the ref has been altered by thread a to have just 4 - 9 left
15:40	hiredman	in a comute there is no conflict
15:40	pjb3	then thread b does the drop, leaving 7 8 9 and everybody is happy
15:40	hiredman	you are describing alter's behaviour
15:40	Chouser_	pjb3: I think that's right.
15:41	pjb3	thread a got 1 2 3 and thread b got 4 5 6
15:41	pjb3	hiredman: so what happens differently if I replace alter with commute?
15:41	hiredman	in a comute, the last one in wins
15:41	pjb3	so in the case of commute, if would just blindy do the drop, not checking for conflicts?
15:42	hiredman	there are no conflicts with commute
15:42	pjb3	gotcha
15:42	hiredman	so why would it check?
15:42	pjb3	so a transaction never restarts when there is just commute in there
15:42	pjb3	I get it now
15:43	pjb3	so to round out my example from above, if I incorrectly did commute instead of alter, both threads would get 1 2 3
15:43	pjb3	which is wrong
15:43	pjb3	and 4 - 9 would be left in the ref
15:43	Chouser_	two threads doing the commute, each dropping 3 would still end up dropping 6 total.
15:44	Chouser_	no, 7-9 would be left in the ref
15:44	Chouser_	the commutes would all happen, just not necessarily in the same order as seen inside the transactions.
15:48	pjb3	Chouser_: ah, you are right, both threads would get 1 2 3, but would each drop, so only 7 8 9 would be left
15:48	pjb3	so 1 2 3 would get processed twice
15:48	pjb3	and 4 5 6 never would
15:48	Chouser_	I think that's right.
15:49	pjb3	that;s all assuming the threads actually interleave in that way I described above
15:49	Chouser_	right, it would be a race condition -- sometimes you'd get unwanted results.
15:49	pjb3	this would definitely be one of those nasty concurrency bugs you might not catch until the app is in production
15:49	Chouser_	which is why I use 'alter' until I'm quite sure that 'commute' is ok.
15:49	Chouser_	:-)
15:50	rhickey	pjb3: alter is always correct, so no need to get into commute until you are trying to solve a performance issue
15:50	pjb3	rhickey: good point
15:50	pjb3	or unless it is a simple counter and you are just using inc
15:51	rhickey	pjb3: there are lots of valid uses of commute, like making an entry in a map
15:51	pjb3	sure
15:51	Chouser_	I wonder if premature optimization is frequently caused by insufficiently interesting problems.
15:51	rhickey	you don't care if someone has added something else in the meantime
15:51	rhickey	Chouser_: :)
15:51	pjb3	rhickey: you might care if someone has already set a value for that key, right?
15:52	rhickey	pjb3: yes
15:52	rhickey	more useful for a cache-like thing
15:52	Chouser_	the function you pass to commute will be run twice?
15:53	rhickey	or generated keys
15:53	pjb3	rhickey: you missed it while you were gone, but now I actually understand why I need to use alter :)
15:53	rhickey	Chouser_: yes, twice
15:53	rhickey	pjb3: great!
15:54	Chouser_	so merge-with might sometimes be a useful option in a commute.
15:59	rhickey	Chouser_: yes, good example
16:12	rfgpfeiffer	Java interop seems to choke on inner classes
16:12	rfgpfeiffer	http://gist.github.com/48138
16:16	rfgpfeiffer	I don't use inner classes myself, i found this in a paper and wanted to try it out on the REPL
16:16	Chouser_	rfgpfeiffer: the problem is not the inner class but the anonymous package
16:17	Chouser_	I moved R into a package P, and then (.makeAnI (new P.R)) works fine, no import needed.
16:18	rfgpfeiffer	Chouser_: thanks, I will try it
16:26	edw	Hi. My net connection sucks (or will suck once I leave the coffee shop) and I was wondering if there's a nice downloadable set of docs (PDF, HTML tarball, or something similar).
16:27	Chousuke	well, you can always use find-doc and doc in a clojure REPL. Other than that, there's the (non-free) clojure book beta
16:28	Chouser_	there's a PDF of the website, but it may be too out-of-date now to bother with.
16:29	hiredman	you could just print the website to pdf
16:29	Chousuke	though special forms don't have very useful doc strings. All the info of them is on the website
16:29	Chouser_	the html pages have print stylesheets, so yeah, you might try what hiredman said.
16:29	edw	Thanks. I haven't read enough of the docs to know that procedures have documentation.
16:30	Chousuke	(doc find-doc)
16:30	clojurebot	Prints documentation for any var whose documentation or name contains a match for re-string-or-pattern; arglists ([re-string-or-pattern])
16:37	edw	Thanks. I'm making about 40 PDFs right now.
16:38	danlarkin	you can always just download a copy of the website if you want
16:41	pjb3	danlarkin: how do you download a copy of the website?
16:42	danlarkin	wget can follow links
16:44	hiredman	looks like however I did it already got pushed out of my shell history
16:44	pjb3	danlarkin: Is it really as easy as wget --magic http://clojure.org?
16:44	pjb3	or do you have to do a bunch of hacking to get a reasonable local copy?
16:46	danlarkin	yeah, wget -m http://clojure.org
16:46	hiredman	I think http://www.easysw.com/htmldoc/ is what I used
16:46	hiredman	made a pdf of the website
16:47	pjb3	danlarkin: that didn't work, some error about a certificate
16:48	hiredman	actually I guess I used the .org version
16:48	pjb3	wget --no-check-certificate -m http://clojure.org
16:48	pjb3	that gets past the cert error, but then you only get index.html
16:51	danlarkin	shrug
16:51	danlarkin	-m stands for --mirror
16:51	danlarkin	which "Turn on options suitable for mirroring. This option turns on recursion and time-stamping, sets infinite recursion depth and keeps FTP directory listings."
16:51	pjb3	danlarkin: hmmm..well, it don't work :)
17:01	danlarkin	ok, here's an incantation that works for me
17:01	danlarkin	wget --no-check-certificate --mirror -k -w 2 -p clojure.org --convert-links clojure.org
17:02	danlarkin	-p flag probably not necessary
17:09	pjb3	danlarkin: all the links start with /
17:10	pjb3	Would have to either run it through a web server locally or figure out a way chomp those off
17:11	danlarkin	donno, I'm no wget master
17:11	danlarkin	maybe there's an option for chomping those
17:26	danlarkin	if I'm merging two hash-maps together and I want to remove an element from the first, the appropriate way to do that would be associate it with nil in the second, right?
17:26	danlarkin	,(:foo (merge {:foo 'bar} {:foo nil}))
17:26	clojurebot	nil
17:26	danlarkin	,(:foo {:not-foo 'bar})
17:26	clojurebot	nil
17:27	Chouser_	a nil value is not the same as a non-existent entry
17:28	Chouser_	I don't think there's any way to use merge or merge-with and end up with fewer entries than when you started.
17:28	danlarkin	yeahh
17:28	Chouser_	do you have a list of keys you want to remove?
17:28	hiredman	(doc dissoc)
17:28	clojurebot	dissoc[iate]. Returns a new map of the same (hashed/sorted) type, that does not contain a mapping for key(s).; arglists ([map] [map key] [map key & ks])
17:29	danlarkin	Well I want a function to return a hash-map and I'll merge that with another
17:29	danlarkin	but if the function wants to /remove/ an element...
17:29	hiredman	dissoc
17:30	Chouser_	can it return a 2-item vector? [#{set of keys to dissoc} {map to merge}) ?
17:30	danlarkin	Hmm
17:30	hiredman	,(dissoc {:a 1 :b 2} :a)
17:30	clojurebot	{:b 2}
17:30	danlarkin	Chouser_: yes I suppose it could, although that's uglier :-/
17:30	hiredman	,(apply dissoc {:a 1 :b 2} #{:a :b})
17:30	clojurebot	{}
17:31	hiredman	danlarkin: why can't the function just dissoc the element it wants to remove?
17:32	Chouser_	danlarkin: if you're sure you never want to have a nil value in your final map, I bet we could write something nice to use nil as a sentinel to mean dissoc
17:32	danlarkin	hiredman: because if I have the function return a hash-map and merge that with another that's no different than just not returning the element from the function
17:33	danlarkin	Chouser_: mmm. yeah it will be allowed nils now that I think about it. I guess I could use :BALLS or something :)
17:34	danlarkin	perhaps I'll just have this function return the entire map and not merge it, even though that's amazing either
17:34	Chouser_	yeah, you could pass in the other map and have the function do the merging.
17:35	danlarkin	yeah
17:37	clows	when i have an anonymous function within an anonymous function ponder what does % refer to in that case?
17:38	danlarkin	can't nest #() forms
17:38	clows	ok
18:07	danlarkin	so who's excited for a sweet night of clojure programming?!
18:08	rhickey	I am!
18:08	danlarkin	woo hooo
18:13	grosours	hi there
18:14	rhickey	hi
18:26	stuhood	could coercion and type hinting be combined somehow?
18:26	stuhood	the coercion example on the wiki is really simple, but it is already an example of coercion being ugly
18:27	stuhood	from
18:27	stuhood	(defn foo [n] (loop [i 1] (if (< i n) (recur (inc i)) i)))
18:27	stuhood	to
18:27	stuhood	(defn foo2 [n] (let [n (int n)] (loop [i (int 0)] (if (< i n) (recur (inc i)) i))))
18:29	stuhood	would be nicer to use:
18:29	stuhood	(defn foo [#^int n] (loop [#^int i 1] (if (< i n) (recur (inc i)) i)))
18:29	dreish	I think having to give extra information to the compiler so it can make your code go faster is always going to be inherently "ugly". That's somewhere way down the list of reasons premature optimization is forbidden.
18:29	hiredman	stuhood: how is that nicer?
18:30	stuhood	it doesn't contain another level of nesting
18:30	stuhood	for the let
18:30	sp00oon	hey all. was wondering if it was worth my time & money to buy the Stuart Halloway beta book
18:31	dreish	sp00oon: If you're just starting out, I'd say absolutely.
18:40	sp00oon	dreish: Yes. Am just getting my toes wet ;) Thx.
18:42	stuhood	also, it isn't really worth making a ticket about, but 'foo2' at http://clojure.org/java_interop#toc36 won't compile because it contains an extra paren
19:45	LARefugee	Anyone see Charles Nutter's recent talk about the JRuby implementation at InfoQ?
19:58	danlarkin	LARefugee: I haven't, link me?
20:00	LARefugee	danlarkin: http://www.infoq.com/presentations/nutter-jruby-jvm-lang-summit;jsessionid=4F95BB3A93601B4AE6F69BE064CEBEDD
20:00	danlarkin	thanks
20:01	LARefugee	It was gnarly. Ruby is very difficult to make fast.
20:01	LARefugee	On the jvm at least
20:04	dreish	Yet just when you thought no one could invent a slower language, along comes Groovy.
20:06	bitbckt	LARefugee: it isn't particularly quick on C, either. REE is somewhat better, though.
20:08	bitbckt	Charlie likes to puff about JRuby being comparable in speed to Ruby 1.9 and quicker than Ruby 1.8.6
20:08	bitbckt	but that really isn't saying much
20:22	LARefugee	I haven't looked at REE too closely. Besides better memory performance what's the biggest win?
20:25	LARefugee	Ruby's been around since 1993! No decen implementation yet. 1.9 was supposed to be a proof-of-concept on the way to 2.0.
20:27	LARefugee	I was thinking JRuby might be it but after Nutter's talk I'm not so sure people should trust it.
20:40	danlarkin	this talk makes me think JRuby is just like
20:40	danlarkin	not worth it
20:40	danlarkin	with the amount of work arounds they have to do
20:42	LARefugee	danlarkin: I've read Nutter say that the jvm is a good platform for dynamic languages. Sure didn't seem like it, at least not for ruby.
20:44	danlarkin	srsly
20:55	dreish	I think it helps if your language features correspond reasonably closely with what the computer can actually do in a reasonable amount of time.
22:26	LARefugee	clojurebot: logs?
22:26	clojurebot	logs is http://clojure-log.n01se.net/
22:57	Chouser	clojurebot, mind your grammar. "logs are"
22:57	danlarkin	patches welcome
22:57	Chouser	heh
22:57	danlarkin	couldn't resist, haha
23:00	danlarkin	:-o someone actually using clojure-json, sweeeet http://github.com/sethtrain/clojure-github/blob/e27d790078307ecf40840d1c0f9817e03f8e6ea3/src/org/buntin/github/email.clj
23:04	danlarkin	I might change the namespace
23:04	danlarkin	having my name in there bothers me
23:05	durka	i mean, you did write it
23:06	danlarkin	yeah but
23:06	danlarkin	it's lame
23:07	Chouser	danlarkin: have your CA in? You could lobby to have it in contrib.
23:08	danlarkin	true
23:20	durka	goodnight all
23:20	durka	this marks the end of winter break, so we'll see how much time school permits for clojure hacking
23:22	danlarkin	you make your own destiny!
23:44	danlarkin	joshua choi's fnparse is really cool
23:57	danlarkin	now if I could just remember BNF from university