#clojure – 2010-07-16

2010-07-16

00:43	Bahman	Hi all!
02:11	bortreb	How do I upload all the jars that I've hand-pick for my project to clojars, all under by group id?
02:27	bortreb	what happens if you screw up uploading something to clojars? can you remove it?
02:28	chouser	I think you can send email to ask that it be removed. :-/
02:30	robtp	hey - does anyone care to critique this for style and idiomatic usage? http://gist.github.com/478019
02:31	robtp	that's the prisoner-lightbulb problem
02:31	robtp	and other than the fact that storing turned-off and turned-on is redundant
02:32	bortreb	I wouldn't put (main) in the file itself because that will trigger it when it is 'used'
02:32	robtp	and then, another question - is there a readymade function to count the number of elements of a collection passing some test?
02:33	robtp	count-passes(coll, #(> % 5)) ; for [5, 7, 2, 9, -1] => 2
02:34	bortreb	you could always combine count and filter
02:36	bortreb	(defn count-passes [pred? coll] (count (filter pred? coll)))
02:48	cais2002	,((fn count-passes [pred? coll] (reduce #(+ %1 (if (pred? %2) 1 0)) 0 coll)) #(> % 5) [5 7 2 9 -1])
02:48	clojurebot	2
02:53	robtp	ahh, nice
02:54	chouser	,((fn count-passes [pred? coll] (count (filter pred? coll))) #(> % 5) [5 7 2 9 -1])
02:54	clojurebot	2
02:54	chouser	bortreb's is nice
02:55	cais2002	will filter create another copy of coll ?
02:57	chouser	it will lazily walk coll as count forces it to
02:57	chouser	so no, there will not be a full copy of coll alive in memory
03:00	cais2002	i mean a filtered copy of coll being created?
03:07	bortreb	Is it possible to delete stuff from clojars if you make a mistake?
03:21	robtp	in my test case, the reduce method works many times faster
03:21	robtp	~5-6x
03:21	clojurebot	No entiendo
03:21	robtp	~5-6x
03:24	cais2002	robtp: that's what i expect, as it avoids creating a filtered coll
03:41	bortreb	On my machine my version is about 20% faster
03:41	bortreb	,(time (dotimes [_ 30] (+))
03:41	clojurebot	EOF while reading
03:41	bortreb	,(time (dotimes [_ 30] (+)))
03:41	clojurebot	"Elapsed time: 1.155 msecs"
03:45	bortreb	,(time (dotimes [_ 50] ((fn count-passes-reduce [pred? coll] (reduce #(+ %1 (if (pred? %2) 1 0)) 0 coll)) even? (range 100))))
03:45	clojurebot	"Elapsed time: 26.85 msecs"
03:45	bortreb	,(time (dotimes [_ 50] ((fn count-passes [pred? coll] (count (filter pred? coll))) even? (range 100))))
03:45	clojurebot	"Elapsed time: 7.049 msecs"
03:51	kuwabara	I can't seem to compile a class, not even the example from the doc. It says: "Could not locate clojure/examples/hello__init.class or clojure/examples/hello.clj on classpath", although the source is in clojure/examples/hello.clj.
03:51	kuwabara	How do I add "." into the classpath ?
03:56	bortreb	first off, you can literally type "." in the -cp argument to java
03:56	bortreb	you also have to have the ./classes directory on the classpath to compile files
03:57	bortreb	are you using emacs and connecting via slime?
04:01	kuwabara	bortreb: no, I'm simply at the repl.
04:02	kuwabara	I added "." in the cp when running clojure, but I get the same error.
04:03	kuwabara	echo "(compile 'clojure.examples.hello)" \| java -cp /usr/share/java/clojure.jar:. clojure.main
04:05	kuwabara	Oops. I renamed clojure/examples/hello to clojure/examples/hello.clj and there is no more FileNotFoundException.
04:05	bortreb	that's great
04:05	kuwabara	but still java.io.IOException: No such file or directory (hello.clj:1)
04:06	kuwabara	Line 1 of hello.clj is: (ns clojure.examples.hello (:gen-class))
04:08	esj	Morning all.
04:08	bortreb	you may try a more complete (:gen-class)
04:08	kuwabara	Found it. -cp /usr/share/java/clojure.jar:./classes:. works.
04:08	bortreb	like
04:08	bortreb	(:gen-class
04:08	bortreb	:name rlm.push
04:08	bortreb	:main true)
04:09	bortreb	what did you change?
04:10	kuwabara	I added ./classes
04:10	kuwabara	which seems to be the hardcoded destination of compiled files, but it's not added to the cp by clojure
04:11	bortreb	yeah
04:11	bortreb	you can change compile-path to get a different destination
05:27	cais2002	what's the best way to do this in clojure: opts=[]; if (condA) opts+=[valA]; if (condB) opts+=[valB]; if (condC) opts+=[valC]; return opts;
05:37	esj	cais2002: dunno if its the best, but a seq comprehension might help
05:38	esj	something like
05:38	esj	,(apply + (for [c '([1 1] [0 2] [nil 3]) :while (first c)] (second c)))
05:38	clojurebot	3
05:38	esj	where the first elementi in each pair is your condition, and the second the value
05:38	boojum	cals2002: (let [opts []] (cond condA (conj opts "valA") condB (conj opts "valV) ..)
05:39	esj	or leave out the apply + if you want it as a seq of the values
05:39	mjul	boojum: we need to reduce over the list - evaluation stops on the first true in cond
05:40	boojum	mjul: true
05:41	mjul	cals2002: are you trying to append to the list for each true condition or just get the sum of the vals for which the corresponding condition is true?
05:41	cais2002	esj: I end up using reduce again, but similar to ur approach
05:41	esj	cais2002: reduce is awesome
05:41	cais2002	mjul: append.. but I want to know the general way to do it
05:41	esj	cons ?
05:42	esj	conj if you're using vectors, say.
05:42	cais2002	I mean the python way I mentioned above is intuitive to me.. but the clojure versions are not that obvious
05:43	esj	,(into [] (for [c '([1 1] [0 2] [nil 3]) :while (first c)] (second c)))
05:43	clojurebot	[1 2]
05:46	mjul	ejs: sweet :-) using for is so much more readable than reduce
05:46	esj	mjul: especially for pythonistas
05:48	cais2002	esj: talking about this, could explain why the reduce version is not faster?
05:48	cais2002	,(time (dotimes [_ 50] ((fn count-passes-reduce [pred? coll] (reduce #(+ %1 (if (pred? %2) 1 0)) 0 coll)) even? (range 10000))))
05:48	clojurebot	"Elapsed time: 580.593 msecs"
05:48	cais2002	,(time (dotimes [_ 50] ((fn count-passes [pred? coll] (count (filter pred? coll))) even? (range 10000))))
05:49	clojurebot	"Elapsed time: 529.725 msecs"
05:50	esj	cais2002: i'm afraid i can't, except to speculate that the provided higher order functions are likely to be better written than what you or I could do.
05:51	cais2002	I thought filter would create another list, while reduce does not..
05:51	bortreb	don't forget about derefrenceng
05:51	bortreb	,(into [] (for [[cond? value] [ [ true 1] [true 2] [false 3 ] [true 4]] :when cond?] value ))
05:51	clojurebot	[1 2 4]
05:53	Chousuke	cais2002: creating a new list isn't necessarily very expensive at all
05:54	Chousuke	cais2002: the clojure core functions make use of a whole bunch of tricks that improve performance, so doing things in a way that "seems" more efficient is not guaranteed to be so.
05:55	cais2002	Chousuke: if the elements are not simple structure, will that make a difference?
05:57	Chousuke	what do you mean by simple structure?
05:58	Chousuke	cais2002: rhickey just has put a lot of effort into making map/filter/for/into etc. really fast so that you don't need to write contrived code to get performance.
06:00	Chousuke	~def reduce
06:00	Chousuke	reduce is fast too though
06:00	cais2002	Chousuke: I am just wondering whether it's only to create the pointers to point to the objects or it's replicating the objects/elements.. simple refers to (range 10000), it's all integers in the list
06:01	Chousuke	in java you only have pointers.
06:01	Chousuke	except if you have primitives
06:01	Chousuke	s/java/JVM/
06:02	Chousuke	and the integers created by range are objects too
06:03	Chousuke	since you can't have a list of primitives.
06:04	Chousuke	But then JVM optimisations will kick in and all those object allocations will suddenly be virtually free, in the best case :P
06:04	bortreb	heh the jVm makes stuff "virtually" free :)
06:05	Chousuke	heh, no pun intended :P
06:08	cais2002	,(into [] (concat [1 2] [3 4]))
06:08	clojurebot	[1 2 3 4]
06:08	cais2002	,(vec (concat [1 2] [3 4]))
06:08	clojurebot	[1 2 3 4]
06:09	cais2002	thanks, guys, my code looks a bit easier to understand now..
06:24	cais2002	88 guys
06:37	mjul	LauJensen: hej! the Docjure lib for spreadsheet import/export is now open source: http://github.com/ative/docjure
06:46	zmila	mjul, it can read/write xlsx? so based on latest version of POI
06:46	zmila	our project uses old version, only for xls (2003) files
06:46	LauJensen	mjul: Great! Did you used a hacked version of Lein for that? :)
06:48	zmila	maybe the project was created before the -jure commit :)
06:52	mjul	it was created before the -jure commit :-) (it has been underway since 2009)
06:53	mjul	- and it reads/writes xlsx, too
07:30	powr-toc	Hey... is anyone using cljr http://github.com/liebke/cljr
07:31	powr-toc	It looks to be a pretty awesome complement for lein, for the times when you don't want a project, and just want a quick repl for experimenting with libs etc...
07:32	powr-toc	I was wondering though, if anyone knows whether you can get it to work with a .user.clj file
08:08	jowag	is it possible to dump the current environment?
08:13	zmila	right question is half of the answer. what is enviroment?
08:17	Kttmm	we found the solution of the problem of yesterday. There was some old code in the Library/Java/Extensions directory which was loaded and caused some troubles
08:17	Kttmm	thanks to all for the help
08:19	rhudson	jowag: if you mean system environment vars, (System/getenv)
08:21	jowag	I mean all the clojure Vars, all the stuff I've defined and loaded from .clj files
08:22	jowag	lets say I've been hacking in REPL and I want to save my stuff and later continue with it
08:22	rhudson	(ns-publics ns) maybe?
08:26	jowag	ok that will give me all the vars in the current ns, now what is left is how to dump a var
08:26	powr-toc	hmm I can't seem to get add-classpath to work properly with cljr... does it work ok in lein??
08:31	rhudson	jowag: any defn or macro is gonna be a problem
08:50	Bjering	I find time really neat for interactivly test runtime performance of what I do, is there an eqvivlant function for memory usage, something like (mem-usage [value] (...)) to give me how many bytes a particular value is occupying?
09:01	ragnard	How (if possible) can I write a function or a macro that, given a function as an argument returns a namespace qualified symbol (or a name/namespace pair) that can be used to resolve the given function?
09:02	neotyk	defn: lol, you must be getting notified quite a lot ;-)
09:02	defn	:)
09:02	defn	ragnard: i can answer that but i need to pull up my editor
09:04	ragnard	defn: cool, excitedly waiting... :)
09:04	defn	ragnard: you could use (meta)
09:06	rhickey	chouser: whither finger trees?
09:06	defn	ragnard: (ns-name (:ns (meta #'doall)))
09:07	defn	,(ns-name (:ns (meta #'doall)))
09:07	clojurebot	clojure.core
09:07	defn	(:name (meta #'doall))
09:07	defn	,(:name (meta #'doall))
09:07	clojurebot	doall
09:07	defn	ragnard: would using that work for you?
09:08	chouser	rhickey: haven't touched them in ages. they work but the api and probably the performance should be improved.
09:08	rhickey	chouser: did you ever compare to the functional java ones?
09:09	chouser	no, that's at the top of my list for once the book is out of the way
09:09	defn	,#^meta
09:09	clojurebot	EOF while reading
09:09	chouser	...can see the light at the end of the tunnel now. And by tunnel I mean the process of adding index links
09:10	chouser	rhickey: if I can't match function java performance, I have officially failed. :-)
09:10	ragnard	defn: yes, thank you... I didn't realise I could use meta for this...
09:10	defn	#^ was deprecated, yeah?
09:11	ragnard	defn: so basically, all vars have metadata containing their name, and namespace (amongst other stuff)
09:12	defn	i believe the answer to that ragnard is yes
09:12	defn	but i only have ever used this with core
09:13	defn	it might not work on all vars
09:14	defn	it looks like it does... (def foo 9) (meta #'foo)
09:14	rhudson	i believe the metadata is put there by def defn defmacro etc, so anything defined "the usual way" should be ok
09:14	raek	how often is the list on clojure.org/contributing updated?
09:14	defn	yeah rhudson
09:14	ragnard	defn: The docs says: http://clojure.org/special_forms#def
09:15	defn	rhudson: do you know if defmacro behaves similarly
09:15	rhudson	suspect so, but don't know
09:16	defn	and the answer is yes
09:16	chouser	rhickey: you have a finger tree use case or something?
09:17	defn	priority queue?
09:19	chouser	sorted set or map often works well for priority queue.
09:21	raek	rhickey: sorry for bugging you, but do you happen to know if my CA has arrived? (from Rasmus Svensson)
09:22	rhickey	chouser: it would be a nice addition to Clojure, I think. No specific use case here
09:22	rhickey	raek: sorry, it's been a couple of weeks since I last checked the box. Will try to get there today
09:23	raek	ok, thanks!
09:23	raek	acknowledged.
09:24	chouser	rhickey: ok. fwiw the possibility of getting finger trees included in Clojure has been and is a primary motivator for my work on it, so thanks for bringing it up again.
09:24	chouser	a few more weeks and I should be able to start making progress on it again.
09:25	rhickey	chouser: I periodically get asked about persistent data structures with efficient insertion, and reluctantly admit Clojure hasn't got one yet
09:26	chouser	sorted sets and maps :-) But I know what you mean.
09:28	chouser	testing the performance of my code vs. PersistentQueue and PersistentTreeMap was a bit discouraging.
09:37	LauJensen	chouser: How discouraging? :)
09:43	chouser	pretty discouraging. I forget the actual numbers, but conjing onto a vector is fast
09:50	AWizzArd	rhickey: The search box on the upper right side of http://clojure.org/ produces an error when being used.
09:50	AWizzArd	chouser: was the PersistentTreeMap more efficient?
09:51	chouser	for anything that existing clojure collections can do, they're faster than my figer trees are right now.
09:59	rhickey	AWizzArd: it says "Search is temporarily unavailable." So, search is temporarily unavailable.
10:18	AWizzArd	Will read-lines be moved from clojure.contrib.io into clojure.java.io sooner or later?
10:22	pjstadig	rhickey: saw the keyword GC change
10:23	rhickey	pjstadig: work ok for you?
10:23	pjstadig	haven't tested it just yet, but i think it will
10:26	neotyk	AWizzArd: I've released ahc-clj 0.1.1 with your suggestion on NPE, thanks!
10:37	Bahman	Hi all!
10:45	yacin	does = not work for java arrays?
10:45	yacin	,(= (into-array Byte/TYPE (map byte (range 10))) (into-array Byte/TYPE (map byte (range 10))))
10:45	clojurebot	false
10:49	AWizzArd	neotyk: oh cool!
10:50	defn	,(into-array Byte/TYPE (map byte (range 10)))
10:50	clojurebot	#<byte[] [B@53ff89>
10:50	defn	(into-array Byte/TYPE (map byte (range 10)))
10:50	defn	,(into-array Byte/TYPE (map byte (range 10)))
10:50	clojurebot	#<byte[] [B@184681f>
10:51	defn	yacin: they're not equal?
10:51	yacin	nope: http://osdir.com/ml/clojure/2010-03/msg01184.html
10:52	yacin	looks like it just compares the references
11:01	tomoj	did prim and friends make it into beta1, I wonder?
11:03	chouser	no
11:03	chouser	I think they've been officially pushed to post-1.2
11:10	tomoj	darn
11:26	defn	is there a way to print the full contents of a java array?
11:27	defn	i mean the obvious answer is yes, but using aget and looping doesn't seem very elegant
11:29	jkkramer	,(seq (into-array [1 2 3]))
11:29	clojurebot	(1 2 3)
11:31	AWizzArd	defn: for multidimensional arrays you will have to manually traverse them
11:55	tomoj	is there no way to test whether something is a java array?
11:59	AWizzArd	tomoj: yes
12:00	AWizzArd	,(let [x (byte-array 5)] (and (class? x) (.isArray x)))
12:00	clojurebot	false
12:01	AWizzArd	,(let [x (byte-array 5)] (and x (.isArray x)))
12:01	clojurebot	java.lang.IllegalArgumentException: No matching field found: isArray for class [B
12:01	AWizzArd	ok, no, .isArray must be called on a class
12:01	AWizzArd	so, it would be more like
12:02	AWizzArd	,(when-let [c (class (byte-array 5))] (.isArray c))
12:02	clojurebot	true
12:02	AWizzArd	,(when-let [c (class 42)] (.isArray c))
12:02	clojurebot	false
12:04	tomoj	ah
12:05	tomoj	I was surprised not to see (array? x)
12:06	AWizzArd	(def array? #(when-let [c (class %)] (.isArray c)))
12:06	AWizzArd	(def array? #(boolean (when-let [c (class %)] (.isArray c))))
12:06	AWizzArd	or if-let vs boolean
12:08	arohner	defn: pprint handles arrays, I believe
12:08	arohner	defn: or, it definitely handles 1-d arrays, not sure about 2-d
12:40	mefesto_	clojure couchdb driver "clutch" no longer on github?
12:42	bpsm	mefesto_: http://github.com/ashafa/clutch ?
12:42	mefesto_	bpsm: ah thanks, i guess i had a bad link
12:59	tomoj	username changed
13:42	savanni	Hi,all. I haven't been around in a while, but I ran into a question today.
13:43	defn	savanni: shoot
13:43	savanni	Is it idiomatic to, when a function encounters an error that it needs to report back up, raise an exception?
13:43	defn	i guess i don't see why not
13:43	savanni	and if so, how do I define new exceptions these days? The gen-and-load-class function that I see mentioned in a few places is not present in the clojure API documentation or in either version of clojure I have.
13:45	defn	that's a good question
13:45	savanni	Although I am considering just saying (throw (proxy [Exception] ["my error message"])), but I'd prefer to pattern match on the class of the exception.
13:45	ataggart	why bother with a proxy at all?
13:45	defn	^^
13:45	ataggart	(throw (Exception. "my error message")) works fine
13:45	savanni	Oh, in that case, you're right.
13:46	savanni	But i'd still like to define my own exception classes.
13:46	ataggart	then, you'll need to gen-class iirc
13:46	ataggart	but usually custom exceptions are a waste
13:46	savanni	Why is that?
13:46	savanni	err...
13:46	savanni	why are they a waste?
13:46	Hodapp	ugh
13:46	Hodapp	I got C++ all over me again
13:47	Raynes	Well, why would you need them?
13:47	Hodapp	how do I wash this off
13:47	defn	Hodapp: have a pressure washer?
13:47	Raynes	I've never needed DudeYouGaveMeTheWrongInformationException before.
13:47	Hodapp	defn: nah
13:47	Hodapp	defn: that's only good for Lispy languages... the water gets underneath all the parens
13:48	ataggart	in almost every case an exception indicates an unrecoverable condition anyway, just throw a RuntimeException
13:48	defn	Hodapp: as a service to the community ill hose you off, might sting a bit at 3000 PSI though
13:48	Hodapp	defn: wait till I get off work, I'm just gonna get covered in C++ again if I wash off
13:48	savanni	umm... no, I am working in cases where exceptions need to be handled. A runtime exception would not be nearly expressive enough. But I could possibly just match on the error string.
13:48	defn	good point.
13:48	ataggart	svanni: example of where the need to be handled, pls
13:48	defn	Hodapp: until then, enjoy the filth! :)
13:49	ataggart	I fail at typing today
13:49	ataggart	savanni: can you give an example of where they need to be handled?
13:49	ffailla	hello, does anyone know if we can define our own constructor via defrecord
13:49	ataggart	ffailla: no
13:50	savanni	Okay... user gets an object from a database, makes some modifications, then submits the object back. In the meantime, another user modified that same object and my code notices that the save would destroy something I don't want to destroy. So, I throw an exception which a high-level handler catches and provides a proper recovery interface to teh user.
13:51	ffailla	ataggart: thanks
13:52	ataggart	There are other, possibly better, ways to handle such cases
13:53	savanni	perhaps. I'm thinking of returning results using something like Haskell's Either structure.
13:53	savanni	failing a sanity check isn't necessarily exceptional, at least not in the same way that total database failure or total disk failure would be exceptional.
13:54	ataggart	in the java world such exceptions would be checked (i.e., derived from Exception, not RuntimeException), and the caller would be forced to handle it. Clojure doesn't force such behavior, thus intervening levels between handler and thrower can break in unexpected ways
13:56	ataggart	using typed, checked exceptions just isn't really a good fit
13:56	savanni	I'm much more experienced with Python than with Java, and we don't have checked exceptions there. But, again, the only way to return an expressive error is with an exception.
13:56	ataggart	yes, but "return[ing] an expressive error" is not your only option
13:57	ataggart	at least not from the code that detects a mid-air collision
14:00	ataggart	that said, you can also use error-kit
14:00	ataggart	http://richhickey.github.com/clojure-contrib/error-kit-api.html
14:01	savanni	Okay, I'll study that for a while.
14:44	mefesto_	is there a way to simply download a jar from clojars instead of having to use leiningen/maven?
14:45	savanni	Yeah. Hit the "browse" link on clojars.org and just delve down into the hierarchy until you find the jar files.
14:45	mefesto_	savanni: ahh thank you :)
14:55	rsh	is there a function to set a var's root binding without supplying a function? I really just want to set it to a value
14:59	bulters	Gday all...
15:04	raek	thinking of it, we clojurians use maps pretty much everywhere
15:04	raek	it's indeed a powerful data structure
15:04	technomancy	but, but--alists are functionally equivalent!</common-lisper>
15:04	programble	abloo
15:05	programble	heh
15:05	programble	lispy has no maps, uses alists
15:05	bulters	So I should consider myself lucky not having programmed in common lisp?
15:05	raek	I like how simple clojure makes usage of maps
15:06	technomancy	bulters: depends; are you often nostalgic for the 80s?
15:06	programble	=>72 / 24
15:06	ataggart	technomancy: what OS do you use?
15:06	programble	no?
15:06	bulters	technomancy: I'm from 1984
15:06	technomancy	ataggart: ubuntu
15:06	programble	->72 / 24
15:06	sexpbot	=> 72
15:06	programble	:\
15:06	programble	lies
15:07	bulters	technomancy: So not too much to be nostalgic about...
15:07	programble	lololol
15:07	programble	wtf is wrong with me
15:07	programble	->(/ 72 24)
15:07	sexpbot	=> 3
15:07	qbg	CL pathnames are just so weird
15:07	bulters	Although, I still have a movie of a 3 year old bashing on a MSX2 ;-)
15:07	qbg	Clojure makes CL look ugly
15:08	programble	lots of things do that
15:12	ponzao____	I have a small noob question, which is not from a real problem I am suffering, just something I stumbled onto and didn't quite grasp why it does what it does. I have defined a struct (defstruct Foo :a), I am trying to map with :a over a list of Foos (map :a '((struct Foo 10))) -> (nil), if I use (map :a (list (struct Foo 3))) I get (3). If I use a map instead of a struct in both cases I get (3), just wondering what is the reason for this.
15:13	arohner	ponzao____: ((struct Foo 10)) tries to call the struct
15:13	arohner	try [(struct Foo 10)] instead
15:13	AWizzArd	well, not that, because it is quoted.. but, it is (list (list foo))
15:14	AWizzArd	and (get '((100)) :a) ==> nil
15:14	programble	a quoted lists, nothing inside gets evaluated
15:14	ataggart	^
15:14	programble	use vectors
15:14	arohner	oh right
15:14	arohner	(:a struct) (:a Foo) (:a 10)
15:14	arohner	no
15:15	programble	'((+ 1 2)) is literally ((+ 1 2)), not (3)
15:15	ataggart	I can't think of a case outside of macros where one needs to use literal lists in clojure
15:16	ponzao____	ataggart, I've seen them used in some examples, are they something that are not recommended?
15:16	arohner	ponzao____: quoting is annoying, so it's just more convenient to use vectors
15:16	ataggart	and is visually useful
15:17	AWizzArd	It may help some newcomers to litterally write out quote from time to time, as in (map :a (quote ((struct foo 10))))
15:18	bulters	makes a mental note to quote lists
15:18	programble	no, make a mental to note to always use vectors
15:18	ataggart	alternately, don't use lists.
15:18	ataggart	damn my slow fingers
15:18	ponzao____	Why is the behavior different for maps and structs?
15:18	bulters	ataggart: You're telling me not to use lists in a lisp?
15:19	arohner	(list (struct Foo 10)) is also more convenient that quoting
15:19	programble	vectors are lists... just... different...
15:19	programble	vector-ish
15:19	ponzao____	(map :a '({:a 10})) -> (10)
15:19	arohner	ponzao____: that map is a literal, while (struct Foo 10) is a function call (that needs to be evaluated) to produce a struct
15:20	arohner	the quote prevented evaluation
15:20	ponzao____	arohner, aaaah okay, well that explains it.
15:20	ataggart	bulters: yes, when simply constructing a literal datastructure.
15:21	ponzao____	arohner, That brings up another question I wondered at some point: How can I force the evaluation of quoted code?
15:21	ataggart	eval
15:21	arohner	ponzao____: eval, or backticks
15:21	bulters	ataggart: I almost thought you were serious ;-)
15:22	arohner	in this case `(~(struct Foo 10)) would work
15:22	arohner	that says, build a quoted list, but evaluate the things that start with squigglies
15:23	arohner	ponzao____: though 99% of the time, you don't need eval
15:23	ataggart	not enough 9s
15:24	ataggart	I've used eval once in all the clojure I've written
15:25	ponzao____	arohner, Ok. As I said before my "problem" was not something I really ran into. Thanks for the help to you and everybody else. I think the biggest learning curve in Clojure (and other Lisps?) comes from understanding the evaluation and macros.
15:39	raek	basically, functions and macros are very similar:
15:39	raek	functions: (apply f (map eval args))
15:39	raek	macros: (eval (apply m args))
15:41	AWizzArd	,(doc apply)
15:41	clojurebot	"([f args* argseq]); Applies fn f to the argument list formed by prepending args to argseq."
15:41	AWizzArd	if m is a macro then apply won't work on it
15:42	raek	yes, that was just a rough scetch demonstrating the differences in evaluation of functions and macros
15:42	raek	I once made a lisp toy language
15:43	raek	I thought it'd be a good idea to be able to apply macros
15:43	raek	...and special forms
15:43	raek	(x true (do-foo) (do-bar))
15:44	raek	that could do completely different things if x was a function, a macro, or a special form
15:45	raek	e.g. if x evaluated to the special form object 'if'
15:45	somnium	Im guessing this was an interpreter?
15:46	raek	yes
15:46	raek	compiling this would not be very easy
15:46	TimMc	It would certainly not be as optimizable.
15:47	TimMc	(You could not compile it to bytecode.)
15:47	somnium	[if (= (%typeof x) if) ...]
15:48	somnium	maybe if it was lazy you could compile it
15:50	KirinDave	programble: Sorry you had to endure python
15:50	raek	i once began on a lisp with only parentheses
15:50	raek	() was 0
15:50	TimMc	Heh.
15:50	raek	(x) was (inc x)
15:50	raek	((())) = 2
15:51	raek	all functions had numbers
15:51	programble	KirinDave: lol i use python all the time
15:51	raek	say, 3 is +
15:51	KirinDave	programble: My condolences.
15:51	programble	i like it, obv
15:51	raek	((((())))()(())) -> (+ 0 1) => 1
15:51	TimMc	KirinDave: Hey now, someone has to like it.
15:51	programble	raek: im scared
15:52	raek	ok, 4 is let
15:53	raek	(4 <binding> <body>)
15:53	raek	hrm
15:53	programble	lol
15:53	raek	I think I solved naming with a special lookup functoin
15:54	raek	(lets call it 5)
15:54	raek	(5 3) is lookup variable 3
15:54	somnium	raek: I think the only legal identifiers should be sequences of [{}]...
15:55	KirinDave	TimMc: No. No one does.
15:55	programble	brainfuck is a great language
15:55	somnium	maybe ()<><>() for complex numbers
15:55	KirinDave	TimMc: Python is the first resort of the unimaginative. Knowing it is one thing. Liking it given the wealth of languages we have today that all do really well? Inexplicable.
15:55	raek	(let (var-6 (+ 1 2)) (+ 2 (lookup var-6)))
15:56	programble	i dont "like" it per se...
15:56	programble	its more just... easy to use
15:56	raek	(4 (6 (3 1 2)) (3 2 (5 6)))
15:56	ponzao____	KirinDave, :D
15:56	raek	(((((()))))(((((((()))))))((((())))(())((()))))((((())))((()))((((((())))))((((((())))))))))
15:57	raek	I should pick up this project again...
15:57	KirinDave	programble: Huh.
15:57	ponzao____	KirinDave, I think I'd like a t-shirt with that
15:57	programble	pythons works, and its not ugly...
15:57	programble	good for scripts if you ask m
15:57	programble	e
15:57	KirinDave	It's pretty ugly.
15:58	programble	well yeah
15:58	programble	not as bad as some
15:58	KirinDave	It's not Erlang ugly.
15:58	programble	doesn't shove oop down your throat
15:58	programble	its easy to do things
15:58	KirinDave	Hah. There Is Only One Way To Do It.
15:59	KirinDave	And It Is Not A Very Good Way But I Am Sure You Rubes Can Handle It. I'm GVR, I Don't Give A Fuck.
15:59	TimMc	raek: Ah, a lookup function.
15:59	KirinDave	Long acronyms in the python community.
15:59	TimMc	I almost buy that.
15:59	somnium	I am still amazed that GVR is actively opposed to adding TCO
16:00	somnium	apparently on the grounds that people would use it do recursion
16:00	TimMc	KirinDave: Unfortunately, PHP and Python can be run interpreted just about everywhere. :-(
16:00	KirinDave	So can PLT Scheme.
16:00	TimMc	KirinDave: Not on any web host I've seen.
16:00	programble	wait wait
16:01	programble	we are talking about how bad python is
16:01	programble	and someone mentions PHP?
16:01	TimMc	programble: As an example of something that is easy to use.
16:01	programble	lolololololol
16:01	TimMc	Not comparing ugliness.
16:01	programble	PHP is not easy to use
16:02	TimMc	PHP is easy to start using, sure. Great docs, great HTML integration, pretty good library of simple data manipulation functions.
16:02	TimMc	It's only hard to use once you try to make your project bigger or scure.
16:02	TimMc	*scure
16:02	programble	PHP is a preprocessor, not a language
16:03	KirinDave	TimMc: PHP's inconsistent libraries are its biggest weakness last time I checked.
16:03	TimMc	KirinDave: Yes. But as a noob I had no trouble just looking up the syntax every few minutes.
16:03	somnium	KirinDave: have you seen Phuby?
16:04	KirinDave	No.
16:04	programble	ruby seems great and all
16:04	programble	but the syntax makes me want to kill myself with a spoon
16:04	somnium	KirinDave: its on github, great stuff
16:04	KirinDave	Wait. Now I have.
16:04	zkim	Hey all
16:04	KirinDave	I wish I hadn't.
16:05	KirinDave	My last words will be, "My God, it's full of stars!"
16:05	somnium	KirinDave: theres a video where they run wordpress in rails
16:06	KirinDave	somnium: I'm going to have nightmares for weeks now.
16:06	somnium	:D
16:06	KirinDave	“When I open my eyes it is still there!”
16:06	programble	lol
16:28	zkim	Anybody doing swing development with clojure?
16:30	savanni	No, but i'm considering it, amongst other gui tools.
16:31	zkim	Ah, was wondering if there was a lib or people just roll their own wrappers
16:31	zkim	What other gui tools are you looking at?
16:48	dakrone	zkim: you could check out swing-utils in contrib: http://richhickey.github.com/clojure-contrib/swing-utils-api.html
16:51	zkim	dakrone: thanks, I'm starting to convert a java app of mine over to clojure, and was wondering if there was a consensus on swing dev
16:59	ragnard	zkim: have you read Stuart Sierras blog posts on clojure/Swing? can recommend them.
17:01	zkim	ragnard: yeah, the heating up clojure & swing post? Definitely helped.
17:02	ragnard	yup, I think it starts with "First Steps With Clojure & Swing"
17:03	zkim	I only saw the one, I'll have to take a look for the others
17:03	ragnard	zkim: first one is at http://stuartsierra.com/2010/01/02/first-steps-with-clojure-swing
17:03	zkim	it looks like the choices are c.c.swing-utils, Licenser's lib, and roll your own
17:04	Licenser	if you want clj-swing feel free to ask questions
17:04	zkim	Hey licenser
17:04	zkim	yeah definitely looking at your lib
17:05	zkim	Got two of your libs up on clojuredocs.org, having trouble with the other two
17:05	Licenser	:) yay
17:14	Raynes	zkim: Have you considered letting users add libraries themselves?
17:14	Raynes	Seems kind of tedious to do all that yourself.
17:15	zkim	Yeah, definitely, there's some manual process around adding libs that I'm trying to get around
17:16	zkim	It's basically pull source -> lein / mvn install -> add to the cd-analyzer deps -> run
17:16	Raynes	:)
17:16	zkim	So I'm trying to automate the first 4 steps
17:17	zkim	That'd be great, it's second or third down on the list after categories
17:18	dakrone	zkim: coming to the meetup next wednesday?
17:18	ataggart	it'd be nice if the "namespaces" list omitted the common prefix
17:18	ataggart	e.g. http://clojuredocs.org/Clojure%20Contrib
17:18	zkim	dakrone: yeah, I'm looking forward to it
17:19	dakrone	zkim: cool, will see you there then :)
17:19	zkim	ataggert: good idea, I'll add it to the list
17:19	zkim	dakrone: cool, hope there's a good turnout
17:19	dakrone	yea
17:33	robtp	any ideas, anyone - java.lang.ClassNotFoundException: incanter.Matrix - like this, maybe: http://www.mail-archive.com/clojure@googlegroups.com/msg14941.html
17:36	cschreiner	zkim: ataggert: and remove the center alignment
17:37	zkim	cschreiner: center alignment for on the ns sidebar?
17:37	zkim	(minus for)
17:38	cschreiner	on the namespaces column
17:38	zkim	It's left aligned for me, which browser / os you on?
17:38	cschreiner	mac/safari/ff
17:38	zkim	hrm
17:39	ataggart	left for me om mac chrome, but looks like its not left due to the elipses
17:40	cschreiner	ataggart: you're right :)
17:40	zkim	yeah, the ellipses were kind of a hack, prior to that the nss would wrap at odd places, or hang over the center
17:40	cschreiner	fooled myself
17:40	cschreiner	make them go away (the prefixes) and group them instead
17:41	cschreiner	no need to repeat clojure.contrib. 170 times on a page
17:41	zkim	agreed
17:41	cschreiner	really love your initiative
17:41	cschreiner	zkim
17:41	zkim	groupings a good idea, I'll play with it a bit
17:41	cschreiner	but, you're no designer ;)
17:41	zkim	thanks, labor of love and all
17:41	zkim	haha no kidding :)
17:42	cschreiner	but I'll look through that for now
17:42	zkim	know any designers that want to get their work out?
17:42	zkim	I'm trying to figure out where I would find somebody like that
17:43	cschreiner	I don't know
17:43	cschreiner	depends on what you want
17:43	cschreiner	would love to throw a css at it though
17:44	zkim	go for it and I'll test it out
17:44	cschreiner	okay
17:44	zkim	html's kind of ugly, but you should have all the hooks you need
17:45	cschreiner	you should try and clean up the html, like make it more 5'ish
17:46	zkim	havn't really looked at 5, they get rid of the div tag or something :)
19:29	lpetit	hi
19:29	lpetit	does this macro already exist ? :
19:30	lpetit	(let [x #"baz\(" y "bar"] (interpol-regex #"(?:a\|`x`\|`y`)") => #"(?:a\|baz\(\|bar)"
19:33	lpetit	more useful (and real!) example: (let [symbol-head #"[a-z\|A-Z]" symbol-rest (interpol-regex #"`symbol-head`\|[0-9]")] (interpol-regex #"`symbol-head``symbol-rest`*")
19:45	lpetit	nobody here ?
19:56	arohner	what's the type hint for an array of Objects?
19:59	defn	Wirth's law: Software is getting slower faster than hardware is getting faster
20:18	ataggart	arohner: ^objects
20:46	slyrus	s/uses/wishes/
20:48	dnolen	Clojure, Node.js and Concurrency Fail, http://dosync.posterous.com/clojure-nodejs-and-why-messaging-can-be-lame
20:49	dnolen	bound to stir up some controversy
20:50	TeXnomancy	dnolen: "how Node.js might fair" should be fare
20:50	dnolen	TeXnomancy: thx
20:50	ataggart	"Node.js is not faster that Aleph" s/that/than
20:51	dnolen	attagart: thx
20:51	ataggart	on a less pedantic note, are there any good guide to getting code out on he Amazon Compute cluster?
20:52	dnolen	attagart: it's pretty simple, just use the CentOS image, install the latest JDK and yr pretty much good to go.
20:52	ataggart	cool
20:52	ataggart	thx
20:58	dnolen	feel free to upvote on HN if you read that
21:15	robtp	logarithm?
21:15	robtp	i can't seem to find it
21:15	rhudson	Math/log
21:15	rhudson	(from java.lang.Math)
21:15	robtp	oh
21:16	robtp	slap
21:31	slyrus	umm... how do I specify a default value for an optional arg for a function again?
21:32	slyrus	i.e. the clojure equivalent of (defun foo (&optional (moose 32)) (1+ moose))
21:32	slyrus	wishes google translate would do cl -> clojure
21:36	slyrus	wait, let me guess... you can't do that in clojure
21:39	raek	you can do it like this:: (defn foo ([] (foo 32)) ([moose] (inc moose)))
21:40	ericthorsen_	Iit appears that after a I AOT a defprotocol and attempt to use it in an extend-type expression I get an error "java.lang.IllegalArgumentException: interface org.model.db.MyProtocol is not a protocol"
21:40	slyrus	ah, so I don't need the &
21:40	slyrus	thanks raek
21:40	slyrus	oh, i see...
21:41	slyrus	it's like i thought. ok.
21:41	ericthorsen_	I also noticed that when AOTing defrecords the namespaces that get prepended are clojure style not java (so this-that does not turn into this_that) which surprised me
21:41	ericthorsen_	Anyone else playing with defprotocol and defrecord?
21:43	raek	or like this: (defn foo [a b & [moose]] (+ a b (or moose 32)))
21:44	raek	not a very beautiful example, perhaps...
21:45	raek	I haven't played with defrecords and AOT at the same time
21:45	slyrus	raek: the (or moose 32) is hardly a default value for the parameter :) yes, I can add another let around the function body and check the value of the parameter, but I guess the whole &optional thing is at odds with clojure's multi-arity thing
21:46	slyrus	so the proper way to do this is as like what you had above
21:46	raek	that's probably the most common way of doing it
21:47	raek	destructuring with maps has support for :or which can provide default values
21:47	raek	this does not exist for sequence destructuring, though
21:48	raek	(let [{a :a, b :b, :or {a 1, b 2}} some-map] (+ a b))
22:04	mudge	hello
22:05	mudge	i declared an atom in one namespace, and i required the namespace from another namespace, but how do I access the atom from the first namespace?
22:05	mikem	mudge: how did you require it?
22:06	hiredman	my guess would be with require
22:06	mudge	i used (:require in the ns declaration of the second namespace and said ":as pt-hook" so i could use pt-hook to reference the name space
22:07	mikem	mudge: then pt-hook/name-of-atom should do it
22:07	mudge	so would I then do: @pt-hook/my-atom ?
22:07	mudge	okay
22:09	mudge	hmm... my second namespace dosen't see pt-hook/my-atom, my first names space is actually using gen-class for AOT
22:10	mudge	i know that if you are going to use methods for a gen-class namespace you have to use :methods and declare your methods
22:10	mudge	but i'm not making a method, just an atom
22:11	mudge	so i guess the question is how do you expose definitions from within a gen-class namespace
22:13	mudge	i have this in one namespace: (def oh nil)
22:13	mudge	i want to refer to in another namespace, like so: pt-tools/oh
22:14	mudge	the first namespace is gen-classed
22:20	mikem	mudge: i'm not sure how gen-class complicates things, sorry
22:22	mudge	ok
22:27	mudge	can two namespaces require each other?
22:31	rhudson	no
22:35	mudge	no what?
22:36	mudge	how do you make a global variable at runtime in clojure?
22:37	rhudson	You can't have two namespaces require each other.
22:37	rhudson	require is a dependency relationship
22:38	mudge	rhudson, great, great to know
22:38	mudge	rhudson: yea, it would be like mutually recursive requiring
22:39	mudge	or something
22:40	rhudson	Yeah, I learned this the first time I wrote a multi-ns program. I had to push some stuff into a different ns to break the loop.
22:42	slyrus	is there a good deftype example around?
22:42	slyrus	oh, nvm the circuitbreaker example...
22:43	slyrus	well, maybe not...
22:46	mudge	def works at compile time, is there something like that, that works at runtime, but has module scope like def does?
22:46	rhudson	,(doc intern)
22:46	clojurebot	DENIED
22:47	rhudson	mudge, look at clojure.core/intern
22:50	slyrus	erm... how do I undef a type?
22:50	mudge	thanks rhudson
22:53	Raynes	mudge: http://clojuredocs.org/v/1779
23:03	slyrus	grumble grumble... the defprotocol/deftype example in the clojure.core API docs doesn't work
23:04	hugod	slyrus: it is missing an explicit "this" argument in the deftype
23:05	slyrus	yes
23:05	hugod	you might try ns-unmap for removing a definition
23:06	slyrus	yeah, that worked. thanks.
23:07	slyrus	oh, no, sorry, I did remove-ns
23:07	slyrus	and rebuilt the ns
23:07	slyrus	i'll try ns-unmap next time
23:10	slyrus	if i have (defrecord Foo [a b] ...) can I specify a default zero-arg constructor that will fill set a and b?
23:12	hugod	you have to write a factory function at the moment, but I believe it is planned
23:12	wooby	slyrus: fyi, reify also requires explicit 'this' for methods (contrary to examples)
23:12	wooby	ran into that myself
23:12	slyrus	factory... bah... what is this java? :)
23:13	hugod	just elide the word if it offends :)
23:14	slyrus	is used to (defclass ...) not DefaultAbstractFactoryGeneratorSingleton or whatever the java equivalent is :)
23:15	slyrus	and (make-instance ...), of course
23:18	hugod	ode to a meta object protocol
23:18	slyrus	heh
23:19	hugod	the doc-string thing is bug #340, but seems to have been relegated to the backlog
23:20	hugod	it even has a patch from fogus
23:27	Bahman	Hi all!
23:40	defn	kisses
23:48	Tekk_	hey, my friend is too lazy to say why clojure is the best lisp and he sent me here >.>
23:49	rhudson	Tekk_: here's a good pitch: http://clojure.org/rationale
23:51	tautologico	is there any nice, built-in 2d matrix data structure available in clojure?
23:51	zkim	Tekk_: it sounds like you have a background in lisp, that correct?
23:54	Tekk_	zkim: learning scheme :P
23:54	zkim	Tekk_: background in any other languages?
23:55	Tekk_	zkim: also know python, some C, some C++, some perl, some ruby........
23:55	Tekk_	bit of everything :P
23:55	Raynes	We don't really deal in "this language is better than x". I'm sure you'll find plenty singing the praises of Clojure, but whether or not it's "the best Lisp" is for you to decide. :D
23:55	Tekk_	I like how simple scheme is, but I havent done clojure yet so not sure how I'll like it ;D
23:55	zkim	Tekk_: Video-wise http://blip.tv/file/982823 really helped when I was starting out
23:57	zkim	Trying to find that dzone video where rich talks about time, anybody got the link?
23:57	zkim	whoops, meant infoq
23:59	zkim	Tekk_: Prob my favorite: http://www.infoq.com/presentations/Are-We-There-Yet-Rich-Hickey
23:59	Raynes	zkim: http://www.infoq.com/presentations/Are-We-There-Yet-Rich-Hickey
23:59	Raynes	I think it's that one.
23:59	zkim	Raynes: Yeah, loved that one