#clojure – 2011-01-29

2011-01-29

00:00	semperos	their dev's don't always get them updated in the maven repo's particularly quickly
00:01	semperos	mefesto: thanks, makes absolute sense
00:01	mefesto	semperos: np
00:58	semperos	really cool that clojureql prints the query as the "string representation" of the table, without having to bind debug like Lau's earlier video shows
01:25	joshua__	&findfn 1 2 3
01:25	sexpbot	java.lang.Exception: Unable to resolve symbol: findfn in this context
01:25	joshua__	findfn 1 2 3
01:25	joshua__	%findfn 1 2 3
01:25	joshua__	$findfn 1 2 3
01:25	sexpbot	[clojure.core/bit-or clojure.core/bit-xor clojure.core/+ clojure.core/unchecked-add]
01:26	joshua__	$findfn 4 5 9
01:26	sexpbot	[clojure.core/+ clojure.core/unchecked-add]
01:26	joshua__	$findfn 2 3 8
01:26	sexpbot	[]
01:32	brehaut	$findfn #(cons %2 %1) '() [1 2 3] '(3 2 1)
01:32	sexpbot	java.lang.Exception: Unreadable form
01:32	brehaut	lame
01:33	brehaut	that'll teach me to read the doc first
07:06	dedeibel	is clojuredocs.org down for you too? :-/
07:08	raek	no. the search gives a 500 though.
07:09	dedeibel	Precise.
07:57	fliebel	how does the mail feature of sexpbot work? just $mail name message, right?
07:58	stephanmg	hello.
07:58	fliebel	hi
08:05	m1ll3`	/msg stephanmg yo
08:05	m1ll3`	lol irssi
08:07	m1ll3`	anybody knows where i can get this SimAnt clojure demo from rich hickey?
08:07	fliebel	$mail clgv I Think the answer is either x=2, y=6 or x=3, y=4. https://gist.github.com/801804
08:07	sexpbot	Message saved.
08:08	fliebel	m1ll3`: No… sounds interesting.
08:09	stephanmg	maybe we should ask kotarak.
08:10	m1ll3`	not on
08:11	incandenza	http://clojure.googlegroups.com/web/ants.clj
08:12	__name__	incandenza: this did not execute with 1.2 last i tried
08:13	m1ll3`	thx. i'll try it
08:13	incandenza	well, that is the original example... it may need some updates by now
08:15	__name__	I am confused that rather many constants are program global. is this recommended?
08:16	jkrueger	assuming that you have two java classes, where one extends the other. if you now extend both of these classes with a protocol, is it possible to call the parent classes implementation of the extended protocol from the derived classes implementation ?
08:16	fliebel	hm, it opens a window with a greeen square for me.
08:16	fliebel	uhm, blue rather
08:20	m1ll3`	you need to start it from repl
08:21	fliebel	hah! howrks!
08:22	fliebel	quite a lot of cpu and threads :)
08:22	incandenza	yup, still works for me, too.
08:22	__name__	m1ll3`: why do you need to start it from repl?
08:22	fliebel	__name__: You need to call some things to start it
08:22	fliebel	see the comment at the bottom.
08:22	incandenza	__name__: to start the program, you need to run the stuff in the 'comment' section at the end
08:23	__name__	oh
08:24	fliebel	I'm not exactly sure hwat these ants are trying to do, and why hey do it so randomly ;)
08:26	m1ll3`	great. works
08:26	m1ll3`	my system's screwed now lol
08:26	incandenza	here's the talk where he explains it: http://blip.tv/file/812787
08:26	__name__	wouldn't it be a bit better to use $CPU threads for that?
08:26	__name__	$ANTS threads sounds like a lot of overhead
08:26	stephanmg	ants seek for food driven by pheromones.
08:34	__name__	this is fun to watch
08:34	fliebel	incandenza: This is clojure 1.0?
08:39	incandenza	fliebel: not sure if it's been updated, but it still works on 1.2. the talk was from april 2008
08:39	fliebel	right
08:46	fliebel	heh, at least he decided to keep his glasses on his nose now...
10:00	bartj	is there a "between" function to check if a number is between two numbers
10:00	bartj	I want to use that instead of:
10:01	bartj	(or (>= n lower) (<= n upper))
10:02	tonyl	not that I know of
10:03	__name__	bartj: why or?
10:05	raek	,(<= 1 5 10)
10:05	clojurebot	true
10:05	raek	,(<= 1 20 10)
10:05	clojurebot	false
10:06	bartj	,(doc <=)
10:06	clojurebot	"([x] [x y] [x y & more]); Returns non-nil if nums are in monotonically non-decreasing order, otherwise false."
10:07	bartj	__name__: oops; yeah, and should be used
10:07	raek	all the <=, <, =, et.c., operations can take more than 2 args
10:07	raek	(< a b c d) is the same as (and (< a b) (< b c) (< c d))
10:08	bartj	so you mean to say:
10:08	__name__	bartj: (defn between [min max n] (and (>= n min) (<= n max)))
10:09	raek	(if (<= lower n upper) (... between ...) (... not between ...))
10:14	bartj	cool! thanks!
10:17	bartj	raek: you always show me a better way :)
10:29	robonobo	whenever i move a function to another namespace and try to use it at the repl, i get the error that the function is already defined, how do i fox that?
10:29	robonobo	s/fox/fix
10:29	sexpbot	<robonobo> whenever i move a function to another namespace and try to use it at the repl, i get the error that the function is already defined, how do i fix that?
10:31	raek	robonobo: you (ns-unmap 'dependent.namespace 'the-var) and then you can use the new one
10:31	tonyl	maybe ns-unmap
10:32	raek	you can also call (remove-ns 'dependent.namespace) to start over completely
10:32	raek	but in that case, make sure the repl is in another namespace and that you remove all namespaces that have used that one too
10:34	dedeibel	I am a bit confused - there is "every?" and "not-every?" and "not-any?" but no "any?", I was also missing something like "not-zero?". Any explanation for that, isn't it inconsistent?
10:34	raek	e.g. scenario: (ns a (:use b)). if you ns-remove b, be sure to ns-remove a too
10:34	raek	dedeibel: an "any?" function can be more general. instead of just returning true, it could return the item itself
10:35	raek	dedeibel: this function is 'some'
10:36	raek	,(some odd? [0 2 4 5 6 8])
10:36	raek	,(some #(when (odd? %) %) [0 2 4 5 6 8])
10:36	clojurebot	true
10:36	clojurebot	5
10:36	raek	so, 'some' is just like "any?", but even more powerful
10:37	raek	but yeah, for the sake of symmetry, one could say that not having 'any?' is a bit inconsistent
10:38	raek	re. complements of predicates: in these cases, it's common to use 'not' or the compound 'if-not' and 'when-not'
10:39	tonyl	or complement
11:24	robonobo	is there a to-the-power-of symbol in clojure?
11:24	robonobo	like ** in python
11:24	robonobo	2**3 = 8
11:30	dedeibel	raek: okay, thanks for the insight
11:32	dedeibel	:D
11:44	tonyl	ronobo: I am not sure, but there is Math/pow
11:46	robonobo	tonyl: i know, but i don't like using long function names when doing math. Anyway, i just made a ** function that calls math/pow
11:47	tonyl	there is also clojure.contrib.generic.math-functions/pow
11:47	tonyl	that is longer
11:47	tonyl	but
11:47	tonyl	y
11:47	tonyl	you can require or use it
11:48	tonyl	or clojure.contrib.math/expt
12:47	neilcj	is there a function that takes a library and returns a list of its public variables?
12:49	Raynes	&(keys (ns-interns 'clojure.core))
12:49	sexpbot	java.lang.SecurityException: You tripped the alarm! ns-interns is bad!
12:49	Raynes	Of course it is.
12:49	Raynes	neilcj: ^
12:50	Raynes	ns-interns returns a map of symbols to vars from whatever namespace you pass it. Calling keys on it just gets you a list of symbols in that namespace.
12:50	Raynes	As for publics...
12:51	raek	ns-publics?
12:51	Raynes	&(doc ns-publics)
12:51	sexpbot	java.lang.SecurityException: You tripped the alarm! ns-publics is bad!
12:51	Raynes	'course.
12:51	raek	"Returns a map of the public intern mappings for the namespace."
12:51	Raynes	Yeah, that's what I was looking for. :D
12:52	neilcj	that works, thanks guys
12:52	raek	the lib has to be loaded first
12:58	jaley	Hi guys! I want clojure.contrib.logging calls to write to a file in /var/log - where should I be looking? I think it's picked up commons-logging from my classpath for a dependent library i'm using. is this configurable in commons-logging.properties or something? I've been googling away about apache commons logging and I just get overwhelmed with complex stuff that I don't need :/
13:07	SergeyD	What do you think of adding ":binding" into the "for" construct? Is it a bad idea because "for" is lazy and it can lead to problems when crossing thread boundaries?
13:07	SergeyD	BTW, what is the right place to propose language changes?
13:08	SergeyD	Like the above )
13:11	chouser	SergeyD: The google group is the place to say such things
13:12	chouser	I don't think I've ever wanted to do a binding inside a 'for'
13:13	chouser	SergeyD: you have a use case for :binding between two iteration expressions in the same 'for'?
13:17	SergeyD	chouser, may be I'm overusing bindings now and not using "for" the right way.
13:17	SergeyD	chouser, I have this: (dorun (for [i (range 4) j (range 3)] (binding [offset-x (* i width) offset-y (* j height)] (make-stuff!))))
13:19	SergeyD	chouser, I will look for the best practices of using bindings.
13:20	_pyr_	hi
13:43	chouser	SergeyD: I'd recommend using binding less frequently. Is there a reason you couldn't pass offset-x and offset-y as args to make-stuff!
13:43	chouser	?
13:43	chouser	pyr: hi
13:47	SergeyD	chouser, I'm exploring using bindings for cross-a-lot-of-functions parameters to make my code more concise.
13:52	LauJensen	Morning
13:52	SergeyD	Evening :)
13:54	Scriptor	Afternoon!
14:06	bartj	doesn't re-gsub replaces globally ?
14:06	bartj	for eg: to replace industries and ltd from company names, I use the following:
14:06	bartj	, (re-gsub #"^(industries\|ltd)[\s]+\|[\s]+(industries\|ltd)[\s]+\|[\s]+(industries\|ltd)$" " " "apar industries ltd")
14:06	clojurebot	java.lang.Exception: Unable to resolve symbol: re-gsub in this context
14:07	LauJensen	SergeyD: Scriptor Look up UGT
14:07	bartj	but, I get "apar ltd"
14:08	bartj	what am I doing wrong ?
14:10	bartj	ie. why isn't the last ltd removed ?
14:10	SergeyD	LauJensen, I see :)
14:16	bartj	it seems to me that re-gsub is not doing a "global" substitute
14:17	LauJensen	bartj: Go check in #perl :)
15:23	robonobo	is there some kind of combination of some and map that returns the first element for which the given function returned true and false when none of them did?
15:25	robonobo	wait, i can use filter and first
15:27	pauldoo	where am I going wrong with this: (let [r (ref 10)] (set! r (inc @r)) @r)
15:27	pauldoo	trying to simply modify a ref..
15:28	mefesto	missing dosync?
15:29	pauldoo	mefesto: adding dosync doesn't help..
15:29	mefesto	pauldoo: and for refs i think you need ref-set
15:30	mefesto	http://clojure.org/refs
15:30	pauldoo	mefesto: brilliant - ref-set + dosync fixed it
15:30	pauldoo	hm.. this is interesting, because I'm only using this var/ref on a single thread
15:31	mefesto	,(let [r (ref 10)] (dosync (alter r inc)))
15:31	clojurebot	11
16:14	mjg123	Hi - I'm having trouble with compojure routes: deploying as a .war to tomcat with context-root of "tb", I know how to create a route which would match (eg) http://localhost:8080/tb/myresource
16:14	mjg123	(GET "myresource ...) or (GET "tb/myresource ...) - neither works.
16:15	mjg123	ahh - s/I know/I don't know/
16:15	LauJensen	mjg123: try moustache, everything nests, ie (app ["tb"] (app ["x"] ... ["y" .. etc))) so that all of your routes are moved up behind /tb/*
16:18	mjg123	nice. The answer to my original question seems to be (GET "/tb/myresource" ...)
16:21	LauJensen	wow you got that from reading up on moustache? Man christophes makes solid docs
16:21	mjg123	was multitasking
16:43	jaley	hi everyone. since updating leiningen 1.3.1 to 1.4.2, i get the help printed followed by a FileNotFoundException no matter what command i'm trying to run. anyone else seen this?
16:45	technomancy	jaley: how did you upgrade? just "lein upgrade"?
16:46	jaley	technomancy: no.. actually i didn't know that existed so i copied the latest version of the script
16:46	technomancy	can you paste the stack trace? I've never heard of that happening
16:47	jaley	technomancy: ok, i just ran lein upgrade and it's fixed
16:47	jaley	Exception in thread "main" java.io.FileNotFoundException: (No such file or directory)
16:47	jaley	at java.io.FileInputStream.open(Native Method)
16:47	jaley	at java.io.FileInputStream.<init>(FileInputStream.java:106)
16:47	jaley	at java.io.FileInputStream.<init>(FileInputStream.java:66)
16:47	jaley	at clojure.lang.Compiler.loadFile(Compiler.java:5817)
16:47	jaley	at clojure.main$load_script.invoke(main.clj:221)
16:48	jaley	at clojure.main$script_opt.invoke(main.clj:273)
16:48	jaley	at clojure.main$main.doInvoke(main.clj:354)
16:48	clojurebot	clojure bot is not immune to ,(iterate inc 0)
16:48	jaley	at clojure.lang.RestFn.invoke(RestFn.java:437)
16:48	jaley	at clojure.lang.Var.invoke(Var.java:373)
16:48	technomancy	I didn't mean literally paste =(
16:48	jaley	at clojure.lang.AFn.applyToHelper(AFn.java:169)
16:48	jaley	at clojure.lang.Var.applyTo(Var.java:482)
16:48	jaley	at clojure.main.main(main.java:37)
16:48	jaley
16:48	jaley	that was the trace, before it fixed
16:48	jaley	technomancy: oh. sorry. clojurebot is upset
16:49	technomancy	is this cygwin or something?
16:49	jaley	linux. ubuntu server 10.04 (i think)
16:51	jaley	technomancy: it's working fine now. will remember there's an upgrade feature next time :)
16:52	technomancy	oh, what was the fix?
16:52	jaley	technomancy: i just ran the upgrade as su, that seemed to work
16:54	LauJensen	hehe
16:54	technomancy	couple weeks and we'll have .deb packages
16:55	jaley	technomancy: for leiningen?
16:56	technomancy	yeah
16:57	jaley	nice. are you sticking it in a launchpad repo thing?
16:57	technomancy	probably
19:24	cc_	hello, quite new to clojure here. I was wondering if someone can clear up a with-open problem for me
19:24	cc_	(with-open [rdr (reader "project.clj")] (count (line-seq rdr)))
19:24	cc_	that one works fine, however for some reason if i try to take 2 instead the stream closes
19:25	cc_	(with-open [rdr (reader "project.clj")] (take 2 (line-seq rdr)))
19:25	cc_	this gives: java.io.IOException: Stream closed
19:25	cc_	any idea why?
19:26	tomoj	&(do (take 2 (repeatedly #(println "foo"))) nil)
19:26	sexpbot	⟹ nil
19:26	tomoj	&(take 2 (repeatedly #(println "foo")))
19:26	sexpbot	⟹ (foofoonil nil)
19:27	tomoj	line-seq and take are lazy
19:28	tomoj	count forces the file i/o to happen inside the with-open by iterating through the whole line seq
19:28	tomoj	with (take 2 (line-seq rdr)), no file i/o happens until the seq is forced, when the repl tries to print the return value
19:28	tomoj	but by then with-open has returned and the reader is closed
19:28	cc_	ah, so i need to force evaluation with doseq?
19:29	tomoj	doseq would be good if you are iterating through the lines and doing something for each
19:29	tomoj	in your example above, (doall (take 2 (line-seq rdr))) should work, I think
19:31	cc_	that worked. Thanks alot for clearing that up :)
21:08	yayitswei	does anyone have experience using clojure and selenium together?
23:24	andyfingerhut	I'd like to do (int x) where x is a primitive long, and truncate the value to the least significant 32 bits if the value is outside the range of an int. And I want it to be as fast as Java could do it, or within 2x the speed Java could. Any thoughts?