#clojure – 2009-08-07

2009-08-07

00:01	JAS415	hmm?
00:01	JAS415	tdd?
00:02	JAS415	i delete all my code and start over all the time
00:02	JAS415	but most of the time i keep it around so i can rewrite it
00:02	tomoj	I ended up with a huge nasty nasty mess
00:02	JAS415	rewrite/cannibalize
00:02	JAS415	yeah
00:02	tomoj	doing things like (first (first blah)) multiple times to deal with shitty functions I had written before
00:02	JAS415	haha yeah that's a problem
00:03	tomoj	and really long chains of crap with multiple anonymous functions and duplication all over the place :(
00:03	JAS415	are you parsing xml or something?
00:03	JAS415	duplication is time for some function passing or a macro though :-)
00:04	tomoj	parsing html
00:04	tomoj	nasty, nasty html
00:05	JAS415	i avoid html when i can
00:05	tomoj	I wish I could
00:05	tomoj	if my university offered the course schedule in JSON I would love them
00:05	JAS415	haha yeah
00:05	JAS415	JSON is beautiful by comparison
00:06	JAS415	and it parses into clojure really nicely
00:06	_mst	if you're willing to delve into java land slightly, I've found htmlcleaner.sourceforge.net nice for parsing "in the wild" html
00:06	JAS415	i think there is a contrib library for xml
00:07	JAS415	if is regular html (i.e. isn't missing anything) it might work
00:08	Derander	clearly clojure needs hpricot
00:08	JAS415	hpricot?
00:08	Derander	ruby library, makes html über easy
00:09	JAS415	how does it work?
00:09	tomoj	we have enlive
00:09	Derander	JAS415: not familiar w/ the internals.
00:09	tomoj	does css selectors nicely
00:09	tomoj	and it's extensible
00:09	Derander	ah, spiffy.
00:10	tomoj	like, it can do more than css
02:12	tomoj	hmm
02:13	tomoj	to me it seems like I have to think backwards to write clojure
02:13	tomoj	I mean, anticipate all the little functions I will need in the future
02:14	tomoj	or write a whole lot of code without compiling, or figure out some trick to have the compiler ignore the high level method I'm working on while I'm coding the smaller ones
02:16	tomoj	...or just learn to use clojure-mode better :)
02:16	mebaran151	you could always just declare the functions
02:16	mebaran151	or mock them up
02:17	mebaran151	also #_ is your friend (it will comment out exactly one expression)
02:17	hiredman	I tend to spend a lot of time in the repl
02:17	mebaran151	so #_(defn my-giant-fuction []) will get rid of that def all in one swoop
02:17	tomoj	ah nice
02:17	tomoj	I think I can just compile each smaller defun individually as well
02:17	tomoj	instead of compiling the whole file
02:17	mebaran151	yep
02:17	mebaran151	but sometimes it's easier just to slurp the whole file
02:18	hiredman	using -> and adding stuff to the chain until I get the desired output
02:18	mebaran151	after quickly marking the fialures
02:18	hiredman	tomoj: what do you mean by "compile"?
02:18	tomoj	previously I was doing slime-compile-and-load-file after every change
02:19	tomoj	which means the whole file has to compile successfully (so either comment out code that calls nonexistant code or declare the nonexistant functions)
02:19	hiredman	oh
02:19	hiredman	:/
02:19	hiredman	I load a function or so at a time
02:20	tomoj	clojure-mode binds lisp-eval-defun to "\e\C-x".. O_o
02:21	alinp	hi
02:21	alinp	how does clojure handle list copying ?
02:22	alinp	I mean ... (conj [1 2 3] 4)
02:22	alinp	it will not mutate the current collection (we all know that)
02:23	tomoj	intelligently
02:23	alinp	and as far as I remember, Rich said that the copying will not be expensive
02:23	tomoj	http://blog.higher-order.net/2009/02/01/understanding-clojures-persistentvector-implementation/
02:23	alinp	ok, thanks tomoj, I'll read about that
02:27	alinp	hmmm
02:27	alinp	there is also some System.arraycopy there
02:28	tomoj	it's amortized
02:30	tomoj	at least, I think so..
02:42	fsm	Hello everyone.
02:42	fsm	Is there a good sample anywhere to she the best practise for reading/parsing binary files in Clojure?
02:43	fsm	see*
03:19	demas	Hi,all. I need your help. I just wanted to use partition-all. I use 'Clojure 1.1.0-alpha-SNAPSHOT'.
03:20	demas	But when I write 'user=> (use 'clojure.contrib.seq-utils)'
03:20	demas	I have got next error message 'java.io.FileNotFoundException: Could not locate clojure/contrib/seq_utils__init.class or clojure/contrib/seq_utils.clj on classpath: (NO_SOURCE_FILE:0)'
03:20	demas	Is there any ideas how to fix this error ?
03:21	hoeck1	demas: adding clojure-contrib.jar to the classpath
03:22	hoeck1	demas: or adding the src folder of your clojure-contrib repository to the classpath
03:22	demas	How can I find clojure-contrib.jar? Is it part of clojure?
03:23	hiredman	~google clojure contrib
03:23	clojurebot	First, out of 4800 results is:
03:23	clojurebot	clojure-contrib - Project Hosting on Google Code
03:23	clojurebot	http://code.google.com/p/clojure-contrib/
03:23	hiredman	ugh
03:23	demas	thanks
03:23	hiredman	that is not right
03:23	hiredman	~google clojure contrib github
03:23	clojurebot	First, out of 1160 results is:
03:23	clojurebot	richhickey's clojure-contrib at master - GitHub
03:23	clojurebot	http://github.com/richhickey/clojure-contrib/tree/master
03:23	hiredman	↑
03:24	demas	ok, thanks
03:24	hiredman	clojurebot: contrib?
03:24	clojurebot	contrib is http://code.google.com/p/clojure-contrib/
03:24	hiredman	clojurebot: contrib is http://github.com/richhickey/clojure-contrib/tree/master
03:24	clojurebot	'Sea, mhuise.
03:24	lpetit	clojurebot: contrib?
03:24	clojurebot	contrib is http://github.com/richhickey/clojure-contrib/tree/master
03:25	lpetit	your bot is really really cool :)
03:25	lpetit	~contrib
03:25	clojurebot	contrib is http://github.com/richhickey/clojure-contrib/tree/master
03:25	hiredman	~botsnack
03:25	clojurebot	thanks; that was delicious. (nom nom nom)
03:26	lpetit	~google eclipse clojure plugin
03:26	clojurebot	First, out of 8920 results is:
03:26	clojurebot	clojure-dev - Project Hosting on Google Code
03:26	clojurebot	http://code.google.com/p/clojure-dev/
03:26	lpetit	Yes!
03:26	lpetit	:)
04:12	Jomyoot	intellij needs better support
04:19	vy	Shouldn't (let [[#^String x y & z] "abcdef"] [x y z]) supposed to throw an error since x is not a string?
04:28	lpetit	hmm
04:29	lpetit	,(let [#^String x "a"] (prn x))
04:29	clojurebot	"a"
04:29	lpetit	no sorry !
04:29	lpetit	,(let [#^String x \a] (prn x))
04:29	clojurebot	\a
04:29	hoeck1	vy: I would say it throws an exception if you call a String only method on it
04:32	lpetit	indeed, it seems it's just for optimizing code for avoiding reflection, but not complaining if the type is not correct but not used for any reflection-avoiding code optimization
04:32	lpetit	,(let [#^String x "a"] (.length x))
04:32	clojurebot	1
04:33	lpetit	,(let [#^String x \a] (.length x))
04:33	clojurebot	java.lang.ClassCastException: java.lang.Character cannot be cast to java.lang.String
04:33	lpetit	,(let [x \a] (.length x))
04:33	clojurebot	java.lang.IllegalArgumentException: No matching field found: length for class java.lang.Character
04:44	lpetit	(binding [warn-on-reflection true] (let [x "a"] (.length x)))
04:44	lpetit	,(binding [warn-on-reflection true] (let [x "a"] (.length x)))
04:44	clojurebot	1
05:19	angerman	how can I do something like (assoc obj {:k1 1 :k2 2}) ...?
05:19	angerman	basically I'd need to destruct the map in place
05:34	Chousuke	angerman: destruct? you mean you want to merge obj and the map?
05:37	lpetit	angerman : (merge obj {:k1 1 :k2 2})
05:42	angerman	Chousuke: well, no I want it to be (assoc obj :k1 1 :k2 2)
05:43	angerman	but yes I guess that's what merge does
05:43	angerman	hmm... I'm kinda stupid today I guess :)
06:32	djpowell	I'm currently using a big map to implement a sort of union-find datastructure, where key-value mappings represent edges in the tree. I guess building that might be sped up a bit by a transient hashmap?
06:37	djpowell	tbh though, most of the stuff I'm doing with clojure involves processing data from database queries, so I haven't had any kind of performance problems with clojure, that aren't be dwarfed by i/o
06:43	angerman	what is an easy way to turn [:x 1 :y 2] into {:x 1 :y 2}?
06:45	jdz	,(apply hash-map [:x 1 :y 2])
06:45	clojurebot	{:y 2, :x 1}
06:45	angerman	aye
07:46	Chousuke	hmm
07:46	Chousuke	syntax-quote behaviour with maps is weird.
07:46	Chousuke	,`{~@(do [1 2]}
07:46	clojurebot	Unmatched delimiter: }
07:47	Chousuke	,`{~@(do [1 2])}
07:47	clojurebot	1
07:47	Chousuke	,`{1 ~@(do [1 2 3])}
07:47	clojurebot	{1 1, 2 3}
07:47	Chousuke	I think I know why that is, though.
08:12	angerman	is there a short hand to create a keyword from a symbol or do I have to go the (keyword (str x)) route?
08:12	jdz	i'd use name instead of str
08:13	rhickey	,(keyword 'foo)
08:13	clojurebot	java.lang.ClassCastException: clojure.lang.Symbol cannot be cast to java.lang.String
08:14	rhickey	works in master
08:14	angerman	ahh, ok :)
08:14	angerman	,(keyword (name 'foo))
08:14	clojurebot	:foo
08:15	rhickey	,(clojure.lang.Keyword/intern 'foo)
08:15	clojurebot	DENIED
08:15	rhickey	nice
08:15	angerman	,(try (keyword 'foo) (catch ClassCastException e (keyword (name 'foo)))
08:15	clojurebot	angerman: Titim gan éirí ort.
08:15	angerman	yes.
08:20	angerman	rhickey: what is better? using defmulti and multimethod or having a map with lambdas that get called?
08:22	jdz	it is actually not the same thing
08:22	angerman	(let [dispatch-map {:a (fn [...] ...) :b (fn [...] ...)}] ((dispatch-selector dispatch-map) arg0 arg1 arg2 ...))
08:23	jdz	there's a benefit of using multimethods: you can pass around a single thing
08:23	jdz	on the other hand, you can wrap your dispatch map in a function
08:25	angerman	hmm i'll play with it a bit
08:26	rsynnott	why does clojurebot speak Irish?
08:26	rhickey	angerman: better how? defmulti automate the map/call process
08:27	angerman	rhickey: so the implementation does pretty much the same?
08:28	rhickey	angerman: multimethods use maps, they also do isa stuff and caching, why not use the most straightforward thing (multimethods)?
08:28	jdz	i'd also go the fewer-wheel-invention road
08:30	angerman	well, using dispatch-maps was something i knew already, I'm just getting used to defmulti
08:31	jdz	after thinking a bit, it appears to me that defmulti does just that, with some clever stuff mixed in
08:31	jdz	in your case, you even don't have to redefine dispatch-selector
08:32	jdz	(or so it seems to me)
08:47	cgrand	rhickey: (-> {} (assoc :a ()) (assoc :a [])) returns {:a []} but would it be ok to return {:a ()}? (no assoc when equality)
08:49	rhickey	cgrand: no, a list is not a vector
08:50	cark	,(= [] ())
08:50	clojurebot	true
08:50	rhickey	if someone were to start conjing on the val at that key they'd get different results
08:50	cark	hum
08:51	cgrand	ok, the last assoc must win for values
08:51	AWizzArd	,(identical? [] ())
08:51	clojurebot	false
08:52	cgrand	BUT right now (-> {} (assoc () :a) (assoc [] :a)) returns {() :a} should it return {[] :a} instead
08:52	cgrand	?
08:53	cark	hey awizard !
08:53	AWizzArd	,(-> {} (assoc () :a) (assoc [] :a))
08:53	cark	,(identical? [1] '(1))
08:53	clojurebot	{() :a}
08:53	clojurebot	false
08:53	cark	,(identical? (list 1) (list 1))
08:53	clojurebot	false
08:53	AWizzArd	cark: = is more like equal in CL
08:54	cemerick	identical? is reference identity, nothing to do with equality
08:54	cemerick	== in java, pointer comparison in C
08:54	cark	but is it ok to have a list and a vector being = ?
08:54	cemerick	cark: absolutely; it's up to the callee of = to decide what equality means
08:54	AWizzArd	= traverses them
08:55	cark	how about the conj argument from rhickey ?
08:55	AWizzArd	there is an infinit set of meanings of what equality means. The most basic one is checked with identical?.
08:55	rhickey	cgrand: keys are based on equality, the values identity test is an optimization
08:56	cemerick	AWizzArd: identical? is not equality. It returns true only if two objects are exactly the same object.
08:56	cgrand	ok, understood, thanks
08:56	cemerick	Which, in general, is hardly ever what you want.
08:57	cemerick	,(identical? "foo" "foo")
08:57	clojurebot	true
08:57	cemerick	,(identical? "foo" (str "foo" ""))
08:57	clojurebot	false
08:58	cemerick	even better:
08:58	cemerick	,(identical? 500 500)
08:58	clojurebot	false
08:58	rhickey	cgrand: the values identity test is an optimization that should be preserved, code can depend on assoc of item already in collection => same collection
08:58	jdz	cemerick: this is why in CL there is eq and eql
08:59	rhickey	,(let [m {:a :b}] (identical? m (assoc m :a :b)))
08:59	clojurebot	true
08:59	jdz	,(let [m {:a 500}] (identical? m (assoc m :a 500)))
08:59	clojurebot	false
08:59	cemerick	rhickey: that's cute
09:00	cemerick	jdz: I've thankfully forgotten all of the shades of equality in CL, but OK :-)
09:00	jdz	i expect many newbies to rave in agony upon finding this out
09:00	cark	actually i liked the precision of CL equality, though there is always more variations
09:00	rhickey	jdz: that's the same value, not the same object
09:00	jdz	rhickey: yes, go tell that to the newbies ;)
09:01	rhickey	jdz: newbies shouldn't be using identical
09:01	cemerick	(almost) no one should use identical, unless you're writing core data structures
09:01	rhickey	if they have that expectation they don't understand equality yet
09:01	rhickey	,(let [m {:a 500}] (= m (assoc m :a 500))
09:01	clojurebot	EOF while reading
09:02	rhickey	,(let [m {:a 500}] (= m (assoc m :a 500)))
09:02	clojurebot	true
09:02	cemerick	I think I've used it once or twice in ~14 months of clojure-ing, and I seem to remember it causing problems.
09:02	angerman	canI filter a map?
09:06	jdz	i was actually recently a bit surprised that rest on a vector returns different objects
09:06	jdz	,(let [s (seq [1 2 3])] (identical? (rest s) (rest s))
09:06	clojurebot	EOF while reading
09:07	jdz	,(let [s (seq [1 2 3])] (identical? (rest s) (rest s)))
09:07	clojurebot	false
09:07	jdz	,(let [s (seq '(1 2 3))] (identical? (rest s) (rest s)))
09:07	clojurebot	true
09:07	jdz	(was writing a tree substitution thing which would not copy a branch if there were no substitutions made)
09:08	rhickey	jdz: how could it efficiently do otherwise?
09:08	rhickey	(vectors not being a linked data structure)
09:11	jdz	well, after thinking about it, it makes perfect sense
09:11	jdz	and i was not really very surprised, just a little bit
09:21	Chousuke	hm
09:24	Chousuke	isn't (binding [foo bar] ...) supposed to establish a thread-local binding?
09:38	gulagong_	hi guys
09:38	cgrand	hi gulagong_
09:38	gulagong_	what happened to a java object which brings my thread to an infinite loop when i try to print it or return it ?
09:39	gulagong_	when printing it prints the classname and than hangs
09:39	gulagong_	while it is printable
09:40	gulagong_	difficult to describe for me but i nailed my problem down to this
09:43	gulagong_	it heats up one core and and my profiler crashes...
09:45	jdz	calculating with infinities is not supported on modern hardware
09:46	gulagong_	jdz: is this an answer to me?
09:46	Chousuke	so what's wrong if I do, in a macro, (binding [foo {}] (macro-driver* form)) and then try to (set! foo (assoc foo :stuff :here)) within macro-driver*?
09:46	Chousuke	I get an error about not being able to change root bindings :/
09:46	jdz	gulagong_: kinda
09:47	jdz	gulagong_: and what do you mean by "it is printable" when apparently it enters infinite loop?
09:48	gulagong_	jdz: these objects can regulary be printed
09:48	gulagong_	jdz: just this one in this situation not
09:49	jdz	gulagong_:so then it's easy - just look for what's different in "this situation"
09:49	gulagong_	jdz: its a matrix from the colt library
09:50	gulagong_	jdz: that is my problem.... i don't find a difference
09:50	gulagong_	jdz: it seems to have disappeared and send my cpu for a search out...
09:51	jdz	gulagong_: what seems to have disappeared?
09:51	gulagong_	the contents of the array
09:52	gulagong_	jdz: it prints the classname and then hangs when trying to print the array-content
09:52	jdz	so the array-content is infinite then
09:52	gulagong_	nope
09:53	gulagong_	#<DenseDoubleMatrix2D
09:53	gulagong_	and then nothing
09:53	jdz	try printing it to a PrintStream with auto flushing
09:54	gulagong_	which would be?
09:55	Chousuke	ah, I needed to use alter-var-root instead of set!...
09:55	gulagong_	jdz: it is a list of these matrices and all but the first element work... although i treat them all the same
09:56	gulagong_	jdz: and in the function returning this list i still have acces to the elements of this object
09:56	jdz	gulagong_: have you tried what i suggested?
09:57	gulagong_	jdz: i don't know which printstream has auto-flushing
09:57	jdz	the PrintStream
09:57	gulagong_	ok
09:58	djpowell	hmm - there is no sorted-set-by, to correspond to sorted-map-by (the constructor that takes a custom comparator)
09:59	Chousuke	user> (syntax-quote (fn [foo#] (+ foo# ~x)))
09:59	Chousuke	(clojure.core/fn [foo__auto__26935] (clojure.core/+ foo__auto__26935 1))
09:59	Chousuke	\o/
10:03	gulagong_	jdz: like this? (with-out-str (prn OBJECT)) ?
10:05	gulagong_	jdz: i used this as return value an it hung up
10:06	jdz	gulagong_: no, like (binding [out (new java.lang.PrintWriter out true)] (prn OBJECT))
10:06	gulagong_	jdz: ok, thanks
10:06	jdz	(untested)
10:07	jdz	or you can use System/out or System/err instead of out when creating that stream
10:14	Chousuke	http://gist.github.com/163921 hairy stuff... still needs some tweaking for special forms at least.
10:16	gulagong_	jdz: i tried and its the same problem
10:17	jdz	gulagong_: well then, since you don't have any output you'll have to work out where the cycle in your data structures is by yourself...
10:18	gulagong_	jdz: there is no cycle....
10:18	jdz	gulagong_: how do you know?
10:18	b4taylor	Well if it's a pure data structure you can't make a cycle.
10:19	gulagong_	jdz: cause i debug- printed this object before- then i return it and its contents brake the print?
10:19	jdz	b4taylor: as mentioned before it is something from external library
10:19	gulagong_	yap, a matrix
10:19	b4taylor	jdz: Sorry, just got here :p
10:20	gulagong_	but i'm not doing any concurrent stuff
10:20	b4taylor	Ah, which one are you using? I tried out Jama.Matrix.
10:20	gulagong_	colt
10:21	gulagong_	and it's great :)
10:21	gulagong_	eccept that it dissapears ;)
10:21	b4taylor	Disappears in what way?
10:22	jdz	gulagong_: it does not disappear. clojure tries to print it, and it [as you say] enters infinite loop
10:22	b4taylor	One problem I've been having is getting back lazy-seqs and having to force them with dorun.
10:22	gulagong_	no, nothing to do with that
10:22	b4taylor	Ah.
10:22	gulagong_	i return it and after that clojure knows the classname but not the contents.... from what i can observe
10:23	gulagong_	but only in one case
10:23	jdz	gulagong_: i told you like 3 times that what you observe is not what really happens.
10:23	gulagong_	jdz: i know
10:24	gulagong_	jdz: so, maybe i should ask how to observe better
10:24	gulagong_	jdz: but my profiler crashes... thats why i'm here - i have no clue
10:25	jdz	gulagong_: you don't need profiler. you need debugger.
10:26	gulagong_	jdz: ok, i'll try to find one for osx
10:28	b4taylor	I'm having some trouble importing from files in my current project. Say I have the files foo/bar/a.clj and foo/bar/b.clj and appropriate (ns foo.bar.a (:import foo.bar.b)) as well as (ns foo.bar.b) lines in each file respectively, why would this fail? Should I add /pathtofoo to my CLASSPATH?
10:28	jdz	you use import for Java packages
10:28	jdz	use for clojure ones
10:28	b4taylor	Oh of coarse.
10:29	b4taylor	Damn, thanks.
10:33	leafw	where are the docs for the xml functions?
10:33	leafw	search "xml" failed in the website.
10:40	bstephenson	well, there is this rather sparse documentation: http://clojure.org/api#toc673
10:43	bstephenson	and clojure.contrib has clojure.contrib.lazy-xml, zip-filter.zml, and a bunch of other xml utility funcs
10:43	bstephenson	s/zml/xml
10:43	leafw	thanks
10:45	leafw	bstephenson: by the way what is the fn to visualize an xml as a JTree in a JFrame? Haven't used this in a while
10:45	bstephenson	do (find-doc "xml") in your repl, and you will find all references to xml in the docs. if you have clojure.contrib library associated with your repl, you will get its funcs too
10:46	bstephenson	,(find-doc "xml)
10:46	clojurebot	EOF while reading string
10:46	bstephenson	,(find-doc "xml")
10:46	clojurebot	------------------------- clojure.core/xml-seq ([root]) A tree seq on the xml elements as per xml/parse ------------------------- clojure.zip/xml-zip ([root]) Returns a zipper for xml elements (as from xml/parse), given a root element ------------------------- hiredman.clojurebot.svn/summary ([tag-map]) takes output of clojure.xml/parse on svn's xml log, returns a vector of [rev-number commit-message] --------------------
10:47	bstephenson	leafw: I will talk to my java form guys here, try to get a quick answer
10:47	leafw	bstephenson: I use to knew it, that's the ugly part
10:47	bstephenson	clojure needs a function "find-old-code". I always need that one!
10:48	leafw	xD
10:51	leafw	bstephenson: I have it, it's clojure.inspector/inspect-tree
10:54	WizardofWestmarc	man after finding out what an idiot I am when it comes to transients now I wish I was set up on my work computer to build clojure from source so I could play with it here. Bah
10:55	rhickey	WizardofWestmarc: no one's an idiot on transients, they are pretty unusual
10:56	rhickey	but best to write it functionally first then add transient/persistent!
10:57	WizardofWestmarc	right. Already rewrote it and pretty sure it'll work now
10:57	WizardofWestmarc	what's funny is I actually DID write the original version functionally. But I didn't wrap my reduce in the persistant! so it screwed up.
10:57	bstephenson	leafw: looks good, should work well for you. we are dealing with xml slightly differently here, so could not find example of us using that in our clojure code.
10:57	WizardofWestmarc	I did it some other way that made it not quite functional.
10:59	WizardofWestmarc	goes to show what happens when you get away from functional programming, you fall out of good habits too quick when things get tough
11:07	WizardofWestmarc	btw Rich, any idea when fork/join will make it back up to master?
13:05	Chousuke	hm
13:06	Chousuke	wonder if it'd be worthwhile to reorganise core.clj a bit.
13:07	Chousuke	I'm trying to implement syntax-quote as a macro, and most of the functions I need to move "up" are small java wrappers.
13:13	Chousuke	for now, it seems my syntax-quote works though.
13:47	LauJensen	Good evening gents
13:48	danlarkin	Lau why did you change from Lau_of_DK
13:49	rsynnott	possibly there is now another Lau in Denmark :)
13:49	cark	or moved to Jensenia
13:50	leafw	any trivial way to read a file line-by-line using line-seq? I.e. how to create a reader from a file path string ?
13:50	leafw	and I don't mean the java way, I know that one ... there must be a clojure (read-file ...) or something
13:52	leafw	and slurp is not useful: not broken into lines
13:52	cark	(with-open [stream (BufferedReader. file-name)] (do-something (line-seq stream) ...
13:52	cark	or something like it
13:53	rsynnott	only a small amount of unsightly java :)
13:53	leafw	cark: the problem is, with that, I have to deal with imports
13:54	leafw	and I'd rather not have imports for something as trivial as creating a reader from a file.
13:54	cark	mhhh there was something in contribs duck-streams ?
13:54	LauJensen	danlarkin: Lau_of_DK was something I picked up as a temporary thing, because 'lau' was already taken. So I figured I might as well grab something a little more descriptive
13:54	leafw	the same way that regex functions hide all the ugliness of java.util.regex.Pattern and friends, so could clojure hide all the FileInputStream etc verbosity with (create-reader filename) or so.
13:55	rsynnott	leafw: well, you could always write a macro to do it
13:55	danlarkin	LauJensen: reasoning accepted :)
13:55	rsynnott	(something along the lines of the CL with-open-file macro, possibly)
13:55	leafw	rsynnott: the point is I'm trying to use clojure like I would use matlab. imports just get in the way, and fully qualified names are tedious.
13:56	leafw	and reading a file it's such an essential thing, one would think.
13:56	leafw	there is slurp. But there isn't a reader-creation function.
13:56	cark	you could fully qualify BufferedReader
13:56	cark	so no imports
13:56	rsynnott	(I always have to look up the appropriate commands in whatever I'm using)
13:57	rsynnott	ESPECIALLY in CL; I doubt anyone knows those from memory :)
13:57	cark	or use clojure.contrib.duck-streams/reader
13:57	LauJensen	danlarkin: Hows Madison coming along ?
13:57	rsynnott	':supersede_if_exists' et al :)
13:58	danlarkin	LauJensen: haven't touched it in months :-o
13:58	LauJensen	oh, not good
13:58	WizardofWestmarc	yeah I gave up on Dan and started using Compojure ;-)
13:59	WizardofWestmarc	though I am using your couchdb lib (haven't played with it much but it seems to work)
13:59	leafw	cark: clojure.contrib.duck-streams/reader is just as long. Why not a proper function in core clojure to create a reader? It's not a big deal, and it already has functions to deal with readers (hence it looks like an omision)
13:59	cark	it feels like library stuff to me
14:00	LauJensen	WizardofWestmarc: How are you interfacing with couchdb ?
14:00	cark	you should stick something in that "utils" file you will use with almost every project =)
14:01	leafw	cark: as much lib stuff as "slurp" is. Same thing.
14:01	WizardofWestmarc	Dan has a library on github
14:01	cark	leafw:true
14:01	LauJensen	~couchdb
14:01	clojurebot	I don't understand.
14:01	LauJensen	~clojureql
14:01	clojurebot	clojureql is a quite impressive piece of work
14:01	LauJensen	~clojureql
14:01	clojurebot	clojureql is http://github.com/Lau-of-DK/clojureql/tree/master
14:01	WizardofWestmarc	http://github.com/danlarkin/clojure-couchdb/tree/master
14:02	WizardofWestmarc	only played with it minimally as I haven't had the time to work on my clojure/compojure/couchdb project, but the very limited testing worked.
14:02	LauJensen	Ok - Was just wondering if this was something I should assimilate into ClojureQL
14:02	WizardofWestmarc	I wouldn't
14:02	WizardofWestmarc	couchdb and sql are too different to keep the libraries together IMO
14:02	LauJensen	No it doesnt look like a candidate
14:03	WizardofWestmarc	document based db instead of an RDBMS
14:03	LauJensen	Yep
14:03	WizardofWestmarc	which is pretty interesting so far.
14:03	WizardofWestmarc	views using javascript, able to easily split up data, all kinda of neat features
14:03	rsynnott	would anyone be interested in something like this: http://common-lisp.net/project/elephant/ on clojure?
14:04	rsynnott	I'm messing around with trying to write an analogue of it
14:04	rsynnott	(it's an object database)
14:04	LauJensen	rsynnott: That makes it alot like Coachdb
14:04	rsynnott	yep, but not quite the same
14:04	LauJensen	What are the major differences?
14:07	cark	LauJensen : about clojureql, does it support runtime query building or is this all macros ?
14:08	LauJensen	You can do everything runtime
14:08	cark	cool
14:08	LauJensen	Yea :)
14:08	cark	there are some examples of this ?
14:09	LauJensen	http://lau-of-dk.github.com/clojureql/2009/07/13/query-syntax.html
14:10	LauJensen	I think this will give you the general idea
14:11	cark	right, but what if i want to dynamically generate the where clause, like suddenly the user decides to use one of my filter boxes
14:11	LauJensen	(query tab [x y z] (= ~user-selection ~threshhold)) , that'll evaluate the environment at runtime
14:13	cark	i see
14:20	LauJensen	cark: Yea. And I know of 2 industry systems now relying on ClojureQL, and its holding up perfectly
14:20	cark	i would be using backend.clj for total control
14:21	LauJensen	cark: the frontend is all the functions you need to worry about. They compile an sql statement to our own format (which is a hash-map basically), then that gets passed through the backend when you call execute-sql or compile-sql, which then form a sql statement fitted for your particular database.
14:21	LauJensen	(note, postgresql create-table is currently under review)
14:22	cark	yes, but the point is that the structure of my queries varies quite a lot in a single function
14:22	cark	i quickly made something like your backend file, but yours is way cleaner
14:23	LauJensen	I dont quite follow
14:23	LauJensen	~clojureql is http://gitorious.org/clojureql/clojureql
14:23	clojurebot	c'est bon!
14:23	cark	say one query would be : select * from calls ... and the other select * from call where a=? and b=?
14:24	cark	and i need to programatically construct these
14:24	LauJensen	So why wouldnt you just wrap that in a cond or condp, calling query as needed?
14:25	cark	because of combinatorial explosion
14:25	LauJensen	If you like, you can Gist an example
14:25	cark	i'd never see the end of it
14:25	LauJensen	(are everybody aware that Emacs integrates Gists very nicely? Push buffer to gist? Pull gist to buffer?)
14:26	WizardofWestmarc	no but I only use GIT/github at all because clojure and several of it's useful libraries are on it :P
14:26	LauJensen	Seriously? :D
14:27	rsynnott	WizardofWestmarc: is there any vcs particularly associated with windows?
14:27	rsynnott	(they got rid of sourcesafe, right? :) )
14:27	Chousuke	LauJensen: gist.el fails to consider clojure-mode in scratch though :(
14:27	Chousuke	LauJensen: even after I added it to the list of knonw modes
14:28	LauJensen	Chousuke: Really? I hadn't noticed
14:28	Chousuke	LauJensen: you don't get syntax highlighting if the file isn't named foo.clj :/
14:28	Chousuke	so I made a scratch.clj :P
14:28	LauJensen	Well, I usually just mark a region and then gist it
14:28	LauJensen	hehe
14:29	cark	LauJensen: i'm not sure we're talking about the same thing, a good example are the html libraries in CL ... they all are macros ... but I prefer having lists that i can tear appart and mix together at run-time instead of compile-time. html libs are easier to me in clojure for that reason
14:29	WizardofWestmarc	rsynnott I prefer mercurial
14:29	LauJensen	cark: I think we are. We use drivers for all our macros to force evaluation of all the items we need to evaluate.
14:29	WizardofWestmarc	it works on every platform easily
14:30	WizardofWestmarc	since it's python based.
14:30	LauJensen	WizardofWestmarc: But seriously.. Windows? :)
14:30	WizardofWestmarc	though to be fair the Github guys made a bridge between git and mercurial
14:30	WizardofWestmarc	Lau: a) dayjob, and b) I still game sometimes :P
14:30	WizardofWestmarc	and I despise apple so Mac isn't an option.
14:30	LauJensen	I have a Macbook which runs Linux perfectly well
14:30	WizardofWestmarc	though my current clojure project is on an ubuntu 9.04 server VM.
14:31	cark	LauJensen: well i'll look into it =) thanks for your time
14:31	LauJensen	np
14:31	WizardofWestmarc	again, despise apple so no macbooks ;-)
14:31	LauJensen	ok, sounds like a political thing
14:32	WizardofWestmarc	not exactly. I don't like microsoft either honestly, but Wine doesn't cut it for some stuff sadly.
14:33	WizardofWestmarc	and my day job is windows dev so it's hard to jump off the deep end and just go pure linux.
15:18	cddr	what's the clojure equivalent of CLOS's `call-next-method'?
15:21	hiredman	cddr: I don't think there is one, but you can use parent and get-method
15:22	hiredman	,(parent String)
15:22	clojurebot	java.lang.Exception: Unable to resolve symbol: parent in this context
15:22	hiredman	:/
15:22	hiredman	,(parents String)
15:22	clojurebot	#{java.lang.CharSequence java.lang.Object java.io.Serializable java.lang.Comparable}
15:23	hiredman	,(get-method print-method Object)
15:23	clojurebot	#<core$fn__6175 clojure.core$fn__6175@199de59>
15:23	hiredman	,((get-method print-method Object) "foo")
15:23	clojurebot	java.lang.IllegalArgumentException: Wrong number of args passed to: core$fn
15:23	hiredman	whoops
15:23	hiredman	,(doc print-method)
15:23	clojurebot	"; "
15:23	hiredman	clojurebot: worthless
15:23	clojurebot	Pardon?
15:25	cddr	hiredman: thanks, I think I get it ((get-method (first (parents obj))) obj)
15:26	hiredman	something like that
15:27	cemerick	cddr: there was a very interesting thread on the group talking about clos, call-next-method, and how to do similar things in clojure, which led to Rich adding get-method (which is a superset of java's super, call-next-method, etc). Can't find it now, of course.
15:29	cddr	yeah I was surprised a search of the groups archive didn't turn anything up
15:30	cddr	does it keep all the history?
15:30	cemerick	google groups search sucks. hard.
15:30	hiredman	↑
15:30	cemerick	you're actually better off querying on google.com with "site:groups.google.com clojure ....."
15:35	WizardofWestmarc	yeah, it's kinda funny how bad groups search sucks, when google's searching groups with the web engine is fine...
15:36	cemerick	well, not fine by any stretch, but not totally useless
15:38	LauJensen	~brain-dump
15:38	clojurebot	brain dump is http://clj.thelastcitadel.com/clojurebot
15:59	LauJensen	~forget clojureql
15:59	clojurebot	I forgot clojureql
15:59	LauJensen	~clojureql is http://gitorious.org/clojureql
15:59	clojurebot	You don't have to tell me twice.
15:59	LauJensen	For those of you who use ClojureQL, we'd moved primarily development to Gitorious (and added a bugtracker). We will still update Github somewhat regularily
16:08	devinus	can anybody point me to a few good tutorials or free books for learning clojure? the clojure.org's few pages of introduction are too high-level for me
16:09	LauJensen	devinus: clojure.org is mostly for reference.
16:09	LauJensen	Google search for "clojure tutorial" yields about 44k results
16:10	djwhitt	devinus: this is a good tutorial: http://java.ociweb.com/mark/clojure/article.html
16:11	WizardofWestmarc	djwhitt's link is an excellent start
16:12	WizardofWestmarc	if you want a ton of useful clojure links I've got a ton that are clojure or clojure useful java stuff on my delicious feed once you get past that: http://delicious.com/wizardofwestmarch/clojure
16:13	WizardofWestmarc	this is a bit out of date now I believe, but also useful: http://www.youtube.com/view_play_list?p=AC43CFB134E85266
16:13	WizardofWestmarc	10 youtube videos about clojure
16:16	angerman	is there a (zip?
16:22	angerman	something like this: (defn zip [a b] (concat [(first a) (first b)] (if (or (= (rest a) '()) (= (rest b) '())) '() (zip (rest a) (rest b)))))
16:22	angerman	but that's quite ugly :/
16:23	Chousuke	hm
16:24	Chousuke	,(map vector [1 2 3] [1 2 3]);?
16:24	clojurebot	([1 1] [2 2] [3 3])
16:26	WizardofWestmarc	the one downside to map is if one list is longer and you want the rest of the longer list tacked on the end it won't do it.
16:32	angerman	,(concat (map vector [1 2 3] [3 2 1]))
16:32	clojurebot	([1 3] [2 2] [3 1])
16:32	angerman	,(apply concat (map vector [1 2 3] [3 2 1]))
16:32	clojurebot	(1 3 2 2 3 1)
17:03	cemerick	this is worth watching out for, if you're passing values back to java:
17:03	cemerick	,(and nil)
17:03	clojurebot	nil
17:03	cemerick	,(and false)
17:04	clojurebot	false
17:05	WizardofWestmarc	oh nice, (and nil false) gives nil back, but (and false nil) gives false back. Interesting.
17:05	WizardofWestmarc	wasn't sure if using them together would work that way or not.
17:07	cemerick	it short-circuits, and in that case, returns the first logically false value it encountered.
17:19	WizardofWestmarc	cemerick: right I understand it, but I wouldn't have thought of that.
17:19	WizardofWestmarc	good thing I rarely pass stuff to java ;-)
17:20	WizardofWestmarc	although at some point I'll probably try scala and mess with interop there.
18:02	fffej	I'm trying to write the "Man or Boy Test" in Clojure (just to try and understand trampoling) but it seems to be failing in bizarre ways, could someone take a look at http://clojure.pastebin.com/d25088b3 and point me in the right direction?
18:03	durka42	what are the bizarre ways?
18:04	fffej	one of the arguments (x4) becomes a function that doesn't return a number (it returns a function instead). I can't see how that can happen
18:05	Chousuke	I have no idea what's happening there.
18:05	Chousuke	:P
18:06	fffej	yeah, it's pretty convuluted!
18:06	durka42	is b supposed to return a function?
18:07	fffej	well, it's used with trampoline and I think that's what I'm supposed to do?
18:08	durka42	well, you return #(b)
18:08	durka42	but b in itself, from the letfn definition, returns a closure
18:08	fffej	yeah, that's the idea of the man or boy test I believe
18:09	dreish	#(b) == b more or less. Was that intentional?
18:10	durka42	so it works with values less than 4
18:10	dreish	Did you mean (fn [] b)?
18:10	fffej	durka42: yes
18:10	fffej	dreish: (fn [] b) is the same as #(b) isn't it?
18:10	dreish	No
18:10	dreish	Same as (fn [] (b))
18:11	dreish	,'#(x)
18:11	clojurebot	(fn* [] (x))
18:12	fffej	so it's plugging into trampoline and my reading of the docs is I should wrap a closure over the tail call rather than a direct call of b. Isn't that what #(b) does?
18:14	hiredman	yes
18:14	dreish	Can't tell what you're trying to do, but in any case, you can just replace #(b) with b.
18:14	dreish	It's already a function.
18:15	fffej	I see what you mean - I should get rid of the # in the letfn and just have it on the tail call
18:16	dreish	That also seems like a good idea.
18:16	fffej	but then I get a stackoverflow, presumably because the body of b is evaluated in the letfn? (and it calls a)
18:17	dreish	#(b) is syntactically a little absurd, by itself.
18:17	fffej	yup, I see that now :)
18:17	hiredman	fffej: have you tried this yet without the trampoline?
18:17	dreish	It says, "Give me a function that is the same as calling b."
18:18	fffej	hiredman: yeah, stack trace with x=4, correct values for x=0,1,2
18:18	fffej	(stack overflow)
18:22	dreish	I think your expectations that Clojure will behave like ALGOL60 are a little ... off.
18:23	fffej	I was adapting a Common Lisp version
18:23	dreish	Where's that?
18:23	fffej	and the test is about recursion and closures, so it's not Algol 60 specific :)
18:23	fffej	http://rosettacode.org/wiki/Man_or_boy_test#Common_Lisp
18:25	dreish	"This creates a tree of B call frames that refer to each other and to the containing A call frames, each of which has its own copy of k that changes every time the associated B is called."
18:25	dreish	You don't have anything mutable, so right away it can't be right.
18:26	fffej	hiredman: yup - it overflows the stack
18:26	fffej	dreish: so k should be an atom right?
18:27	dreish	Maybe.
18:27	fffej	ok, I got it now
18:29	fffej	well, by got it I mean I have something that doesn't crash; now it just produces the wrong results :) Thanks for pointing me in the right direction!
18:40	duck11231	What's the best way to pass the name of a function, execute that function, then modify the name of the function (to refer to a different function) and then execute that one? If I pass the function un-quoted, I can't get the ns and name of the original location, and if I quote it, it's not respecting the alias in place when it was declared
18:40	duck11231	I tried using keywords and converting them, but that resulted in a mess
18:40	hiredman	:(
18:41	hiredman	that sounds pretty horrible
18:41	duck11231	basically, in a different namespace, I wanted to be able to do (show-html (show args))
18:41	hiredman	clear as mud
18:42	Chousuke	you could use resolve
18:42	hiredman	,(resolve (symbol "+"))
18:42	clojurebot	#'clojure.core/+
18:42	Chousuke	,((resolve '-) 1 2)
18:42	clojurebot	-1
18:42	hiredman	,((resolve (symbol "+")) 1 2)
18:42	clojurebot	3
18:45	duck11231	I was trying to use ns-resolve, because the function wasn't refered to in the executing ns, but was having problems. I was trying to be able to return something like {:action :view/show, :format :html, :args [7]} and turn that into (unaliased.ns.for.view/show-html (unaliased.ns.for.view/show 7))
18:46	duck11231	but maybe I need to take a different approach
18:49	hiredman	,((ns-resolve (create-ns 'clojure.core) (symbol "+")) 1 2)
18:49	clojurebot	3
18:50	duck11231	hiredman: thanks, I should try using create-ns
18:51	hiredman	,(doc create-ns)
18:51	clojurebot	"([sym]); Create a new namespace named by the symbol if one doesn't already exist, returns it or the already-existing namespace of the same name."
18:53	hiredman	I would take a moment to think about alternatives
18:54	hiredman	symbol → string → string transformation → resolution to var → function call seems like a bad idea
18:55	duck11231	I agree, it sounded like a good idea when I first though of it, until I looked at what was actually involved
19:12	duck11231	the end result turned out to be not that ugly, but it still seems like it's overly "clever"
19:48	alrex021	I am finding it very difficult to follow the Stack traces in Clojure, am I missing something or is there a better way to view more informative exception stack trace in clojure?
19:51	Chousuke	alrex021: I think contrib has some functions that can clean up the stack trace a bit.
19:53	alrex021	Chousuke: I see, there is a trace lib in contrib
20:35	alrex021	I'm looking at the clojure.contrib online docs and I can't seem to require or use clojure.contrib.stacktrace.. Are the docs old and lib is not there or am I missing something?
20:40	alrex021	I see it seems to have been moved to clojure as this now works (use 'clojure.stacktrace)
20:41	rhickey	current docs: http://richhickey.github.com/clojure-contrib/
20:43	alrex021	rhickey: thanks, I got it bookmarked now
21:11	cemerick	rhickey: do you have any ideas off the top of your head on how to exercise arbitrary code, so as to prime the JIT? We have some UI code that is plenty fast after about 15 seconds worth of use, but it's dang slow (at least w.r.t. user-perceptible responsiveness) before then.
21:12	cemerick	Non-UI code is easy to optimize (just run some sample data through it in the background at app startup), but I don't see any obvious corollary for UI code.
21:13	cemerick	hrm, maybe record gestures with the Robot, serialize them, and use that as sample data on an off-screen UI component...
21:16	hiredman	:(