#clojure – 2009-07-03

2009-07-03

00:46	CoreyWhite	Does anyone know of a syntax highlighter with Clojure support? Or with generic Lisp support that would be fairly easy to adapt to Clojure? (For the web, preferably javascript/jQuery, although I could live with something server-side in PHP.)
00:47	CoreyWhite	I'm aware of the Clojure plugin for SyntaxHighlighter (here: http://travis-whitton.blogspot.com/2009/06/syntaxhighlighter-for-clojure.html), which is quite good . . . but unfortunately SyntaxHighlighter messes with my markup in very unpleasant ways.
00:53	gstamp	http://kai.myownsiteonline.com/clojure/html.clj.html
00:55	CoreyWhite	that seems pretty excellent! Is that your site?
01:04	gstamp	No not mine. There was a recent thread in the mailing list. I plucked the URL from that.
01:05	gstamp	Thread was titled "Displaying Clojure code on a Website" if you'd like to look it up
01:12	Knekk	anyone here use vimclojure?
01:28	Chouser	gah. why can't I have a reader hook!?
03:00	mrpika	t
03:00	mrpika	oops
03:06	Knekk	for a large(ish) multi-dimensional array of mutable data should I use vectors of refs? or Java arrays?
03:08	parthm	Knekk: If you want java interop + performance you can use java arrays
03:09	parthm	are there multiple threads in your program operating on the data?
03:09	Knekk	Would only need performance for the array. I can define the data itself without java interop
03:09	Knekk	yeah, multiple threads will manipulate the data
03:10	parthm	refs of vectors can be a start. if you feel performance is bad you can switch to arrays
03:10	parthm	vectors have a lot of functions to work on them
03:11	Knekk	that's what I am seeing, yeah
03:11	parthm	for most cases vector performance is fine
03:11	Knekk	I am blowing the heap space trying to create the vectors. Need to get my head around the implications here
03:12	parthm	hmm ... do you need all the initialization up front or maybe it can be lazy
03:14	Knekk	even if it's lazy I'll be iterating across all the array elements a number of times to do transformation on the data pretty fast, so all elements will be accessed
03:19	parthm	I probably don't get the use case but even the computation should be delayed and only the relevant values should be generated/computed.
03:19	parthm	user=> (time (def y (map (partial + 1) (range 10000000))))
03:19	parthm	"Elapsed time: 0.904514 msecs"
03:19	parthm	#'user/y
03:19	parthm	user=> (take 5 y)
03:19	parthm	(1 2 3 4 5)
03:19	parthm	user=> (take 5 (drop 1000000 y))
03:19	parthm	(1000001 1000002 1000003 1000004 1000005)
03:19	parthm	user=>
03:20	parthm	sometime I have seen the stack blow when we hold on to the head somewhere.
03:21	Knekk	I am probably not using the proper methods then. I am a n00b. Using (apply vector (map (fn [_] (ref (struct my-struct))) (range large-number))
03:21	Knekk	))
03:22	Knekk	to create one dimension of the array
03:23	Lau_of_DK	apply forces evaluation, thats not the same as parthm's example above
03:24	Knekk	I was basing mine on a different example, and that'd explain why I am blowing the heap
04:46	Knekk	ok, so now I have a better lazy approach to creating a multi-dimensional array of refs
04:52	Knekk	night
05:22	Knekk	laggy tonight
06:46	Chousuke	Chouser: are you handling the clojure-1.0 compatible contrib branch?
08:01	AWizzArd	Is there an efficient built-in function that removes an element from a vector at position n?
08:20	rhickey	AWizzArd: can't be
08:26	AWizzArd	rhickey: is it planned to add new immutable data structures to Clojure, such as doubly linked lists or skiplists?
08:27	rhickey	AWizzArd: finger trees would be welcome
08:27	rhickey	http://en.wikipedia.org/wiki/Finger_tree
08:30	AWizzArd	Finger trees or skiplists ( http://en.wikipedia.org/wiki/Skiplist ) would have to be implemented in Java for performance reasons yes?
08:32	rhickey	no
08:34	rhickey	any data structures need to be persistent
08:34	AWizzArd	yes
08:34	rhickey	so, doubly linked lists not possible
08:34	qra	hi clojure group, this is first time I entered this channel.
08:35	rhickey	qra: hi
08:36	AWizzArd	I see, didn't think about that yet. Anyway, what would you do if you wish to conj up a vector V of structs over which (V) you then run a unification and pattern matching algorithm that wants to remove at (possibly random) positions elements and add new ones?
08:37	rhickey	AWizzArd: what's the significance of the positions?
08:37	qra	how to force 'for' to run through all items in a lazy list?
08:38	durka421	qra: doall
08:38	durka421	or you may be looking for doseq instead of for
08:38	qra	ok
08:38	rhickey	qra: if your 'for' is only for side effects, use doseq instead, otherwise you can call doall on the result of for
08:39	rhickey	or vec
08:41	AWizzArd	rhickey: if the positions won't be important then maybe a set would be right. But if the order must stay the same it is not so easy anymore.
08:43	rhickey	AWizzArd: for splicing we need finger trees
08:43	AWizzArd	I see
08:49	qra	(for [i last-list] (doall (println i)) wont work?
08:50	durka42	for produces a lazy seq, so you want to wrap doall around the entire thing
08:50	durka42	(doall (for ...))
08:51	qra	ok, but i cant understand what's going on
08:51	rhickey	qra: for is designed to return a sequence of values
08:51	rhickey	but yoiu just want to perform a sequence of side effects, so use doseq
08:52	rhickey	(doseq [i last-list] (println i))
08:52	qra	doseq throws some error it expects vector, but I have only lazy-list
08:53	rhickey	for produces the values lazily, so if you never use them, it never produces them
08:54	rhickey	qra: try: (doseq [i (range 3)] (println i))
08:54	rhickey	at the repl
08:55	qra	thank u, it works.
09:02	tashafa	hello all
09:02	danlarkin__	salut!
09:02	tashafa	whats up danlarkin
09:02	danlarkin__	it's finally sunny!
09:03	tashafa	not in mass :(
09:03	danlarkin__	maybe... just maybe it can last all day
09:03	tashafa	massachusetts
09:03	tashafa	i dont think ive seen the sun in a month
09:04	danlarkin__	I was in Boston last weekend, and driving home was hilarious. I left boston in a hazy cloud cover and like 30 minutes west it turned into a beauuuutiful day
09:05	tashafa	thats new england weather for you
09:06	sgtarr_	england weather is worse.
09:06	tashafa	clojure ques.
09:06	sgtarr_	ques?
09:07	tashafa	it escapes me but how do you extend a java class again and override a method
09:07	tashafa	?
09:07	tashafa	in clojure ofcourse
09:07	tashafa	:)
09:08	sgtarr_	i can tell you how to do it in java.. :)
09:08	danlarkin__	proxy
09:09	danlarkin__	unless proxy is gone now
09:09	danlarkin__	it's been a few weeks since I've used clojure :(
09:09	tashafa	same here
09:09	sgtarr_	haha
09:09	sgtarr_	clojure changes that quickly?
09:09	tashafa	i've been in python world
09:09	sgtarr_	the cutting edge!
09:09	sgtarr_	tashafa: welcome back to civilization...
09:10	sgtarr_	naw, I shouldn't talk like that about Python. I use it often and i've used it for many projects since approx 2002
09:10	sgtarr_	But there are some things that bug me...
09:10	sgtarr_	and java is just much better for Enterprise
09:10	tashafa	yup... procedural programming is just mind numbing
09:12	tashafa	after messing with clojure that is
09:13	sgtarr_	yea
09:13	sgtarr_	tashafa: how did you get involved with clojure?
09:14	sgtarr_	interest in lisp from before?
09:14	tashafa	by way of paul graham
09:14	tashafa	but common lisp was just hard to get started with
09:16	sgtarr_	yea
09:16	sgtarr_	I was always fascinated by Lisp
09:16	sgtarr_	and there is a finance company that I was familiar with that used Lisp exclusively, still do, but they used LispWorks afaik
09:17	tashafa	cool
09:21	sgtarr_	I remember that asteroid probe Deep Space 1 also ran Lisp
09:21	durka42	really?
09:22	sgtarr_	It still does actually, even though its ion thrusters have been off since 2001
09:22	sgtarr_	Lisp up there in space, still running silently :)
09:22	durka42	the first google result for "deep space 1 lisp" is that rant about how JPL lost faith in lisp
09:23	sgtarr_	really? weird
09:23	sgtarr_	check out http://en.wikipedia.org/wiki/Deep_Space_1#Remote_Agent
09:23	sgtarr_	the RAX software was lisp
09:23	sgtarr_	and the mission was a huge success
09:24	sgtarr_	from your article:
09:24	sgtarr_	"Based on this experience I think it's safe to say that if not for Lisp the Remote Agent would have failed."
09:25	sgtarr_	"Debugging a program running on a $100M piece of hardware that is 100 million miles away is an interesting experience. Having a read-eval-print loop running on the spacecraft proved invaluable in finding and fixing the problem."
09:25	sgtarr_	Nice. REPL 100 million miles away
09:38	tashafa	hmm
09:39	tashafa	how do you call methods on the parnet class (super) in proxy?
09:43	tashafa	proxy-super
09:45	Chousuke	hm, is that even possible?
09:51	AWizzArd	Is there (maybe in contrib) a foo for doing (foo [1 2 3 4 :x 5 6 7 8 :x 9 10 :x 11]) ==> ((1 2 3 4) (:x) (5 6 7 8) (:x) (9 10) (:x) (11)) ?
09:52	AWizzArd	split-at, split-with, take-while, partition-by, group-by and others don't work
09:55	AWizzArd	my foo call was not complete, it misses something like #(= % :x) or #(not= % :x)
10:02	tashafa	Chousuke: I have no idea
10:02	tashafa	but shouldnt it be?
10:29	tashafa	Chousuke: http://dishevelled.net/Tricky-uses-of-Clojure-gen-class-and-AOT-compilation.html
10:32	Chousuke	interesting
11:31	lisppaste8	AWizzArd pasted "How to group/split contents of a collection into groups?" at http://paste.lisp.org/display/82957
11:32	rzoom	is there a github issue?
11:33	rzoom	rob@eniac:~$ git clone http://github.com/richhickey/clojure
11:33	rzoom	Initialized empty Git repository in /home/rob/clojure/.git/
11:33	rzoom	fatal: http://github.com/richhickey/clojure/info/refs not found: did you run git update-server-info on the server?
11:42	rzoom	nevermind
11:43	rzoom	in the future, use the github specified Clone URL, for .... you know ... cloning
11:43	rzoom	e.g. git clone git://github.com/richhickey/clojure.git
11:52	cgrand	AWizzArd: (s/partition-by #{:x} [1 2 3 4 :x 5 6 7 8 :x 9 10 :x 11])
11:52	cgrand	where s is seq-utils
11:53	AWizzArd	cgrand: ah good, that is much better
12:23	jackdempsey	rzoom: yea, .git on the end :)
12:49	lisppaste8	codyK pasted "already in zip libraries?" at http://paste.lisp.org/display/82962
13:38	Lau_of_DK	Good evening gents
13:39	dysinger	sup
13:50	jackdempsey	evenin
15:31	jackdempsey	anyone familiar with compojure round these parts?
15:39	jackdempsey	is there an idiomatic approach for getting the current time in clojure?
15:39	jackdempsey	reading a variety of ways to ask java, and prety much all end with
15:39	jackdempsey	"i hate the Calendar class" :-)
15:42	Lau_of_DK	I use Joda time for that stuff
15:42	Lau_of_DK	And yea, Compojure is hot
15:42	Lau_of_DK	sizzle
15:43	jackdempsey	k, saw Joda mentioned before as well, gotta check it out it seems
15:44	jackdempsey	sigh
15:44	jackdempsey	This page is unavailable at the moment. Please try again shortly. Sorry for the inconvenience.
15:44	jackdempsey	oh the yak shaving :-)
15:46	technomancy	the JDK calendar is horrible, but if all you want is the current time, it's not bad
15:46	technomancy	(java.util.Date.)
15:48	jackdempsey	hey technomancy , yeah, thanks man, i'm ultimately looking for just the current time in a unix style timestamp
15:48	jackdempsey	i thought it'd be fun to rewrite this in clojure/compojure: http://github.com/jcapote/watercoolr/blob/125707e211b0a3cb6462ea405bb77aefb1618f8b/watercoolr.rb
15:48	jackdempsey	good exercise to learn more, etc
15:48	lisppaste8	Lau_of_DK pasted "Macro this!" at http://paste.lisp.org/display/82973
15:48	Lau_of_DK	Boys - Can somebody shed some macrobiotic light on the question I asked in that lisp-paste ?
15:50	Chouser	macfoo always uses a function named 'foo' exactly twice?
15:52	Lau_of_DK	Yep
15:52	Lau_of_DK	On the first assumption
15:52	Lau_of_DK	But it will use it x number of times, depending on the length of your list, ie "mister" "#clojure" "bar" "baz" etc
15:53	Lau_of_DK	@ Chouser
15:54	Chouser	Lau_of_DK: did you want to pass in the initial string too?
15:54	Lau_of_DK	That would be ideal
15:55	technomancy	jackdempsey: my first project was porting a web app to compojure too, but I found I learned more from writing Mire; I kind of fizzled out on the web app.
15:55	jackdempsey	heh gotcha
15:56	jackdempsey	yeah its kinda painful so far
15:56	technomancy	web apps just have too much incidental stuff to worry about
15:56	jackdempsey	especially coming from rails
15:56	technomancy	might be better to tackle that domain once you've got a grasp on the core language
15:56	jackdempsey	ah
15:56	jackdempsey	i see what you mean
15:56	jackdempsey	not a bad point
15:56	Chouser	(defmacro macfoo [string & subs] `(-> ~string ~@(for [sub subs] `(foo ~sub))))
15:56	jackdempsey	my eyes are starting to glaze over
15:57	jackdempsey	hmm
15:57	jackdempsey	this isn't too bad tho
15:57	jackdempsey	(/ (. System currentTimeMillis) 1000.0)
15:57	Lau_of_DK	Chouser: Man thats nasty :)
15:58	Lau_of_DK	It was the ~@(for...) I couldnt work out, but it makes perfect sense
15:58	Chouser	:-)
16:00	krumholt_	why is it every? but some without "?"
16:01	Lau_of_DK	Chouser, mind if I annote it so that others can benefit?
16:01	Chouser	Lau_of_DK: by all means.
16:01	lisppaste8	Chouser annotated #82973 "Macroed" at http://paste.lisp.org/display/82973#1
16:02	Chouser	krumholt_: the "?" suggests it'll return true or false
16:02	achim	Lau_of_DK: umm, why a macro? that's "reduce" ...
16:02	achim	(reduce #(foo %1 %2) "hi!" ["mister" "#clojure"])
16:02	krumholt_	Chouser, ok thanks
16:02	Chouser	krumholt_: 'some' returns the value returned by the predicate -- could be something other than boolean
16:03	Chouser	achim is absolutely right.
16:03	jackdempsey	heh
16:04	Chouser	I violated the first rule of writing macros.
16:04	Lau_of_DK	Achim... ehm.... I was just setting Chouser up of course, I had it figured out hours ago :)
16:04	jackdempsey	lol
16:05	Lau_of_DK	Chouser you should paste your user.clj .... (defmacro println) etc... :)
16:18	achim	did anybody here have a look at Qi?
16:22	technomancy	can you start nailgun from an already-launched clojure instance?
16:22	technomancy	i'm using (com.martiansoftware.nailgun.NGServer/main (make-array String 0)) to no effect
16:23	rhickey	achim: Qi is definitely interesting
16:29	jackdempsey	ah cool
16:29	jackdempsey	hadn't heard of Qi
16:29	foox	i have three sub-expr in a 'let'. the third gets evaluated before the second; how can i prevent this
16:30	foox	the second sub-expr is a doseq
16:32	drewr	technomancy: I haven't tried nailgun yet. Like it?
16:32	technomancy	drewr: works like a charm
16:32	krumholt_	how can i remove an item from a map?
16:32	technomancy	except for starting the server in an already-running instance; I can't figure that out
16:32	technomancy	krumholt_: dissoc
16:33	krumholt_	thanks
16:33	technomancy	drewr: on the whole it's very simple and obvious
16:33	drewr	krumholt_: Also look at select-keys if you have a bunch to remove.
16:34	drewr	technomancy: Looked like it. I'll give it a shot.
16:34	krumholt_	thanks
16:44	technomancy	if the nailgun server is runnable, can I pass it to a new thread and have the thread run it for me?
16:44	technomancy	how does that interface work?
16:45	technomancy	oh, looks like that works.
17:51	dysinger_	thank goodness for #clojure's active irc channel
17:53	Chouser	hm. a joke?
17:53	Chousuke	:P
17:55	technomancy	I think he means relative to Java IRC channels
17:55	technomancy	#hadoop is like a tomb
17:55	Chouser	ah
17:55	technomancy	and dysinger_ is dancing among the gravestones
17:56	dysinger_	y Chouser - seems like often Java dudes ( I am on ex-10-yr one myself ) just hang out on IRC and don't actually participate in discussion.
17:56	Chouser	ah.
17:56	dysinger_	I've tried to ask a question on #hadoop 4 times - every time there's like 60 people in there but all I get is crickets
17:56	Chousuke	Can you do the moonwalk? Maybe it'd activate the channel.
17:57	dysinger_	I ran naked through the channel
17:57	technomancy	as long as it's not the Thriller zombies...
17:57	dysinger_	but nobody said anything :)
17:57	Chouser	normally I would have assumed you were making a straight statement, but since your comment was the first in over an hour I just wasn't sure.
17:57	dysinger_	seriously :) "dysinger_ runs by naked and nobody notices [2:52pm] •"
17:57	Chouser	heh
18:03	jackdempsey	man
18:03	jackdempsey	this is really interesting, but i feel like i'm starting to walk again
18:03	jackdempsey	except i have arthritis from OO land
18:03	jackdempsey	i'm staring at (let [id gen-id]....) for a while and wondering why i get the function back
18:04	jackdempsey	maybe because thats exactly what i asked it to set id to
18:04	jackdempsey	[id gen-id] will just st id to be the function referred to by gen-id, correct? if i actually want it to be the result i have to do (let [id (gen-id).....) right?
18:04	Chousuke	yes.
18:05	jackdempsey	cool
18:05	Chousuke	first-class functions are fun little things :)
18:05	jackdempsey	technomancy: that little web port is coming along ok....so far the hardest part has been trying to figure out what i can borrow from java......and of course some basic clojure stuff.
18:05	jackdempsey	haha, yep
18:05	jackdempsey	going to take a while to unlearn some bad habits
18:06	jackdempsey	i can't wait to see what this does to my ruby....
18:06	Chousuke	jackdempsey: you'll be using code blocks a lot more I guess.
18:07	jackdempsey	yeah, blocks are already kinda ubiquitous, but i think the way i use them and approach certain problems will certainly be different
18:07	Chousuke	or then you do an assignment and go "wtf, why is the old reference changing too?"
18:07	jackdempsey	i saw somethhing in couchdb earlier and thoguth" but but but, thats a side effect, oh god no!.......oh wait........ahem"
18:07	jackdempsey	lol
18:08	jackdempsey	user=> (def foo #{})
18:08	jackdempsey	#'user/foo
18:08	jackdempsey	user=> (conj foo 1)
18:08	jackdempsey	#{1}
18:08	jackdempsey	user=> (conj foo 2)
18:08	jackdempsey	#{2}
18:08	jackdempsey	that still cracks me up....not used to it at all :-)
18:08	Chousuke	yeah.
18:08	jackdempsey	"where'd the 1 go.........oh......ha"
18:09	jackdempsey	its definitely easier to think about things in the more pure functional sense...appeals to my math side for sure
18:09	Chousuke	I find it easier because functions become true black boxes.
18:09	Chousuke	once they work, you only need to know what they do, not how
18:09	jackdempsey	yep
18:09	jackdempsey	exactly
18:10	jackdempsey	"does that still set that random thing or not......have to go look"
18:10	jackdempsey	man, i really really want to reply with something about refs and STM: http://stackoverflow.com/questions/1080993/pure-ruby-concurrent-hash :-)
18:11	arohner	Clojure makes me more irritated by ruby
18:11	arohner	I get annoyed by things like not being able to pass multiple blocks to a function
18:11	technomancy	yes.
18:12	arohner	and blocks are not a replacement for first class functions
18:12	technomancy	I find myself writing classes for pure IO and keeping them totally separate from the bulk of the logic.
18:12	technomancy	but I've only written like two pages of Ruby since learning Clojure. =)
18:13	Chousuke	arohner: what, you can only pass one? :/
18:13	slashus2	technomancy: Was it your main language before?
18:13	jackdempsey	heh
18:13	arohner	Chousuke: yes, one "normal" block. After that, you have to start passing procs around, which use a different syntax
18:13	jackdempsey	yeah, if you do def (foo, &bar)
18:13	arohner	that, and there are 6 or 7 different kinds of blocks
18:14	jackdempsey	can pass that one normal block, otherwise as arohner says you have to use lambdas
18:14	jackdempsey	hehe
18:14	Chouser	though in a mutable language, first class functions are not a replacement for blocks
18:14	arohner	Chouser: how so?
18:16	arohner	http://innig.net/software/ruby/closures-in-ruby.rb
18:16	arohner	that is a great example of how Ruby is insane
18:16	jackdempsey	oh man
18:16	jackdempsey	lol
18:16	jackdempsey	really exposing the skeletons in the closet now :-D
18:16	Chouser	ruby blocks can use 'break' and such to control the loop they're in
18:16	arohner	ewww
18:16	jackdempsey	lambas can return as well....but procs return differently......and well......yea
18:17	jackdempsey	ruby's an excellent language for some things.....but for others, not so much, and like anything, has its warts
18:17	jackdempsey	k, workout time, later gents
18:28	codyK	is there an existing pretty-printer for xml-zip ?
18:31	Chouser	codyK: you can zip back up to the root and use 'emit' to print it as xml again.
18:35	codyK	good enough, thanks
19:11	_hrrld	Is there a function to tell me if a Var is "bound"?
19:16	Chousuke	_hrrld: (when-let [v (resolve sym)] (.isBound v)) perhaps
19:21	_hrrld	Comically, I can't seem to call resolve on an unbound symbol.
19:22	_hrrld	(declare x)(resolve x) ; Var user/x is unbound.
19:24	achim	_hrrld: (.isBound #'x) seems to do the trick
19:25	achim	resolve is a function, it doesn't even see the x, the compiler tries to substitute it before calling resolve
19:28	_hrrld	That makes sense, and the hash quote does work. Thanks.
19:28	Chouser	That assumes the var exists
19:29	Chouser	which is why Chousuke use 'resolve' first to see if there's even a var named by that symbol
19:37	unlink	hi
20:47	something	if I know the name of the function, is there a way to get the fn definition back during runtime?
20:59	Chouser	something: have you tried clojure.contrib.repl-utils/source ?
21:00	something	Chouser: no I didn't yet. let me take a look at that.
21:01	Chouser	it actually uses the var name not the fn, and it needs to be able to find the original .clj file in the classpath
21:01	something	Chouser: I want to figure out # of arguments a particular fn takes before I invoke it. Is there an easy way to do that?
21:02	Chouser	something: not perfectly, but you could get an 80%-type solution if you have access to the var
21:02	Chouser	if the var has been resolved to an actual fn, or if the fn was never in a var, you're pretty much out of luck.
21:03	Chouser	the var has :arglists metadata you can try to use
21:03	something	Chouser: awesome! let me check that out.
21:05	Chouser	the thing is even if you have the var, it's possible for the var's arglists to have been left out or changed
21:07	something	in what scenario can the arglists be left out?
21:08	Chouser	(def foo (fn [a b c] ...))
21:09	something	Chouser: right,
21:10	something	Chouser: I'm going after the defn case, so I should be ok, but I understand what you are saying.
21:23	something	Chouser: I guess the question is how to get a hold of the var when I only know the string representation of it
21:36	Chouser	something: (resolve sym)
21:46	something	Chouser: ah, thanks
21:49	Raynes	Joining #Concatenative after making less-than-nice remarks on reddit - Awkward.
23:33	Knekk	does clojure provide data/object serialization functionality (for writing to a stream, for instance) or does one need Java interop?
23:34	Chouser	Most Clojure collections can be printed as ascii that can then be read again.
23:35	Chouser	There's also a print-dup var that can be set to make sure you get identical object types when read as when printed.
23:37	Knekk	thank you. I have too much data to keep in memory and need to find an efficient way to offline to disk