#clojure – 2008-10-23

2008-10-23

00:08	AWizzArd	is (ensure ref) basically a lock?
00:19	arohner`	is there a good way to prevent "overwrapping" your arguments because of &rest args?
00:19	arohner`	i.e. (defn foo [& args] args) (foo (foo (foo 1))) => (((1)))
00:20	arohner`	or am I doing something wrong by getting into that situation?
00:30	AWizzArd	What would you expect should (foo (foo (foo 1))) return?
00:31	arohner`	I'm not sure. I'm just not aware of a clean solution to the problem
00:32	arohner`	I could say "if the rest argument is already a list, don't add another list around it", but that is very ugly
00:33	AWizzArd	I don't see the problem
00:33	AWizzArd	If you do [& args] it means args will be a list.
00:36	AWizzArd	Asking "IF the rest argument is already a list .." makes not too much too much sense as it will always be one.
00:37	arohner`	I'm not sure if/where the problem is. All i know is that I'm passing arguments from one rest parameter to another, and I end up with big nested loops.
00:37	arohner`	i.e. that (foo (foo (foo 1))) example. I started with 1 by itself, and ended up with (((1)))
00:38	AWizzArd	oh, maybe you want to magically have the parens around the argument to be removed?
00:38	AWizzArd	(some-function rest) ==> as if you said: (some-function 10 20 30) and not (some-function (10 20 30))?
00:39	arohner`	yeah, sort of
00:39	AWizzArd	(apply foo (foo 1)) ==> 1
00:39	arohner`	I'm not sure what the right solution is
00:39	AWizzArd	you need to apply these arguments, that's the right solution
00:39	AWizzArd	you can not solve it otherwise
00:39	arohner`	huh. ok.
00:39	arohner`	I'll try that
00:39	arohner`	thanks
00:40	AWizzArd	apply is a "magic function" that you can not implement yourself for the current "level" of programming.. You would need to provide one for an interpreter inside your language.
00:40	AWizzArd	(+ 1 2 3) = (apply + '(1 2 3))
01:12	Lau_of_DK	Morning all! =)
06:31	alvin-x	when I run this snippet: http://paste.lisp.org/display/69045 with clojure.lang.Script, I see the output from println, but not data gets to the file on disk; if i do a (. output flush) or (. output close) the string does get to the disk....
06:31	alvin-x	is this a java thing or a manifestation of clojure's lazyness?
06:31	alvin-x	. out* not output
06:32	tWip	I think that's just bufferedwriter
06:32	alvin-x	probably
06:39	alvin-x	it happens at the FileWriter level too; no output without flush/close.
06:43	tWip	what os?
06:43	alvin-x	win32
06:44	tWip	doesn't windows lock files that are open for writing?
06:46	alvin-x	i'm not sure; have to dig in MSDN. i just expect all buffered data to be written out on process exit.
06:46	cemerick	that's definitely not something to be relied upon
06:48	alvin-x	isn't that supposed to happen in unix/posix at least?
06:49	alvin-x	my process cleanly exited --- didn't die by a fatal signal or exception;
06:50	cemerick	I don't know about posix exit semantics, but no VM I've worked with will guarantee that anything is cleaned up before it exits.
06:51	alvin-x	hm
06:51	cemerick	Actually, most specify that you should expect buffered data, finalizers, etc., won't be flushed/run/whatever
06:52	Chousuke	doesn't cost anything to just close everything at the end anyway :)
06:54	alvin-x	not easy to know where "end" is sometimes, without a destructor mechanism...
06:55	alvin-x	no matter, i'll just flush whenever i write
06:55	cemerick	that's what finally blocks/forms are for
06:56	cemerick	flushing on every write essentially eliminates the benefits of buffering
06:59	alvin-x	is there some form in clojure that i could use to ensure file closing?(with-open ?
07:01	alvin-x	:)
07:02	cemerick	yeah, with-open will automatically close the Closable object you bind in it
07:02	cemerick	I don't think there's a form that will autoflush, but most (if not all) outputstream impls flush on close iirc
07:04	alvin-x	ha, this will work for JDBC too. nice.
07:05	jao	hi. in slime, when i compile a file (C-cC-k) and get errors, the compiler-notes window pops, but i cannot navigate from there to the error locations. is that normal?
07:05	cemerick	alvin-x: yes, indeed
08:38	rhickey	anyone want to tackle a simple pprint for Clojure?
08:47	jdz	that would be nice as hell :)
08:47	cemerick	and very helpful in enclojure
08:47	alvin-x	and probably non-trivial
08:48	jdz	well, one could learn a lot from CL's pretty-printer
08:48	rhickey	a first cut could be much less ambitious yet useful
08:49	jdz	like support for print-width and print-length
08:49	jdz	and depth
08:49	rhickey	jdz: yes
08:49	hoeck	and printing 'foo instead of (quote foo)
08:51	rhickey	I just don't see when I'll get time to do it myself
08:51	jdz	i could try doing it, but must finish a paper in a week...
08:51	jdz	and then there is some work queued after that...
08:51	rhickey	Wow - Clojure group just crossed 700 members and 5k messages
08:54	Chousuke	it says here it has 698 members.
08:54	rhickey	My admin screen says 712
08:54	Chousuke	I guess it hasn't updated yet, then
08:55	Chousuke	I just added myself.
08:55	cemerick	db consistency isn't key on g-g :-)
08:56	jdz	cemerick: consistency does not like concurrence
08:58	Chousuke	I keep dreaming of making a roguelike game in clojure but I don't have enough time to get started :/
08:58	cemerick	I'd say that scalability is more the driving factor, but sure :-)
08:58	Chousuke	it'd just be so much fun to include a repl in-game
09:39	lisppaste8	j-dot pasted "ns binding" at http://paste.lisp.org/display/69052
09:40	j-dot	Does anyone know why, in the code I just pasted, the 'bar var is set in the 'user ns instead of the 'foo ns?
09:41	j-dot	How do I go about def'ing a var in another namespace from within a 'do or 'binding expression?
09:42	wwmorgan	j-dot: (resolve 'bar) is nil when I run it. Could you have def'd it in user earlier?
09:43	Chouser	yeah, it's because ns controls the namespace resolution at compile time, so the original value is used when compiling that whole expression. By the time you actually bind and use in-ns to set it, it's too late.
09:44	j-dot	ah, I see ... thanks, Chouser
09:44	rhickey	j-dot: you need to control the ns where the code is compiled - the entire expression is compiled in the user ns, and def resolved there, then you execute the expression, getting runtime effects that don't matter
09:44	j-dot	That makes sense, thanks
10:08	rhickey	looking at proposed do-with, what is the preference - add do-with or breaking enhancement to doto (you'd just have to add . before method names)
10:09	H4ns	rhickey: better modify doto than having two things that do something subtly different in the base language
10:09	Chouser	I'd be content with a breaking change
10:09	H4ns	(certainly, i don't have a large code base that will break)
10:10	Chouser	esp. if it's coming at roughly the same time as a bunch of other simple structural breaking changes (like vectors for binding in if-let, deseq, etc.)
10:10	Lau_of_DK	Good afternoon gents
10:10	Chouser	Lau_of_DK: hi
10:25	walters_	rhickey: is the asm code in clojure a permanent fork or is it safe to use the system asm library?
10:27	charliekilo	aplogize upfront ... I'm watching Cojure for Java Programmers ...I got everything installed (Clojure, Aquamacs, clojure-mode), can bring up inferior-lisp, butr CAN'T figure out how he does that two frames trick with evaluate line in clj document in the inferior-lisp evaluator ... what's the magic key combination?
10:28	Lau_of_DK	The default in emacs is Ctrl-X Ctrl-X I believe
10:29	rhickey	walters_: it's not really a fork, just a snapshot, using a more current version is really a matter of compatibility between ASM versions - what are you trying to achieve?
10:29	tWip	I think it is C-M-x
10:29	walters_	rhickey: we (Fedora) try to avoid shipping duplicated source
10:31	rhickey	walters_: do you ship multiple versions of things?
10:31	walters_	rhickey: yeah, asm2 and asm3
10:31	Chousuke	charliekilo: two frames? do you mean how inf-lisp is at the bottom and the file buffer is at the top?
10:31	charliekilo	neither C-X C-X or C-M-x does not work for me ... is that part of Emacs or clojure-mode
10:32	Chousuke	do you have the clojure repl running?
10:32	charliekilo	Chousuke: yep ... like he does in the video ... top has (. Math PI) and I'm truying to have 3.14... show up in bottom
10:33	Chousuke	C-x C-e works for me
10:33	rhickey	walters_: the clojure asm is just a subset, just what's needed for Clojure runtime, done for size and ease of building
10:33	charliekilo	Chousuke: the bottom has 'user=>' running and I can eval stuff there ...
10:33	walters_	rhickey: aright, i may try to do a patch then to optionally build vs system asm
10:34	rhickey	walters_: ok
10:34	Chousuke	charliekilo: then you should be able to use C-M-x or C-x C-e to evaluate forms in any buffer that's in clojure-mode
10:34	Chousuke	charliekilo: if your buffer is in clojure-mode you should see a clojure menu in the menubar when the buffer is active
10:36	charliekilo	Chousuke: ahh ... it top window one was not in clujure mode ... it works now ... awesome!! ... thanks alot !!!!
10:39	rhickey	walters_: are you going to use jarjar or something to allow multiple libs to use different ASMs?
10:40	walters_	rhickey: that one is a bit of a mess; i think language implementations should probably use a private classloader for now; hopefully the Java 7 module stuff will sort this out somewhat more
10:41	rhickey	walters_: I think private classloader is a non-starter, as classloader issues usually push up to library consumers, containers etc
10:41	gnuvince	rhickey: the "Differences with other lisps" page mentions that the Clojure reader is side-effect free. I'm curious about the kind of side effects the CL reader has; it seems like this ought to be a pure function, take in a stream of characters and produce a data structure.
10:41	rhickey	that's why you see private-packages ASM
10:42	rhickey	gnuvince: the CL reader interns symbols
10:42	walters_	rhickey: well, you could only use the separate classloader for the compiler, the generated bytecode would still be loaded in the main classloader, i think that would avoid most issues
10:43	rhickey	walters_: it gets really sticky, but the consumer often dictates classloaders, so I've been striving to reduce any dependencies on my own
10:43	walters_	rhickey: understood, yeah
10:44	rhickey	I don't see a compelling reason not to sub-package ASM, it's so small
10:57	lisppaste8	Lau_of_DK pasted "Euler52 - Sequences" at http://paste.lisp.org/display/69055
10:57	Lau_of_DK	Gentlemen, I have a case here, were all my debug-steps work as they should, but when I try to produce the end result by parsing a seq of seqs, I get an incorrect output. Can somebody show me the error of my ways ?
11:01	Chouser	Lau_of_DK: can you include an example of find= working?
11:02	Lau_of_DK	Working?
11:02	Chouser	you have an example of it producing incorrect results, right? Can you include and example of it producing correct results?
11:03	Lau_of_DK	No, because if it did produce correct results, we wouldnt be having this discussion :) But its a modded version of this: http://clj-me.blogspot.com/search?q=Google and it seems to work well for cgrande
11:03	Chousuke	Lau_of_DK: nitpick: n-seq could be simply (iterate #(+ n %) n), no?
11:04	Lau_of_DK	If you replace the + with a * then yes :)
11:04	Lau_of_DK	(btw., I like nitpicking, good to learn those things)
11:06	Chousuke	well, + is the correct function to get what your comment has. with * you get: (take 4 (mul-seq 3)) -> (3 9 27 81)
11:07	Lau_of_DK	oh ok
11:08	Lau_of_DK	but, n-seq / map producdes the correct sequence
11:08	Lau_of_DK	If you check the link to Euler, Im searching for the first hit where 1x n and 2x n ... 6x n, use the same digits
11:08	Chousuke	mapping works but the multiplication is unnecessary. :)
11:08	Lau_of_DK	so it needs to be (1 2 3) (2 4 6) (3 6 9) ...
11:11	Chousuke	whoops. accidentally evaluated a lazy sequence in the repl ;(
11:11	Chousuke	an infinite one, too
11:13	Chouser	Chousuke: not uncommon, unfortunately.
11:13	rhickey	print-length patch welcome
11:14	drewr	If I have a data structure of JdbcConnections that I set as available or unavailable in a ref, how what's the best way to block when all of them are busy?
11:14	drewr	s/how //
11:15	drewr	My gut is that Clojure will handle this automatically, but I want to make sure I set it up right.
11:17	rhickey	drewr: use j.u.concurrent for workflow: http://java.sun.com/j2se/1.5.0/docs/api/java/util/concurrent/package-summary.html
11:17	rhickey	maybe Semaphore?
11:18	rhickey	but there is so much presumption in your question
11:18	rhickey	another architecture is to put a fixed pool of resources in a queue - pull one off to work, put it back when done, will block on empty queue
11:18	rhickey	I think that's better
11:19	Chouser	rhickey: you could just about maintain a todo list of things you're not going to do, that others could. pprint, print-length, due diligence on vector binding forms, etc.
11:20	drewr	rhickey: Thanks, that sounds like the behavior I want.
11:21	rhickey	Chouser: yes, definitely, just need to choose where. So far all of the free trac-like things I've seen allow anyone to enter tickets, e.g. Google Code
11:21	Chouser	rhickey: By the way, I spent last evening staring into Numbers.java. I think I get it now -- pretty clever set of indirections.
11:22	rhickey	Chouser: yeah, that still needs profiling
11:23	rhickey	but so far perf is dominated by boxing rather than branching
11:23	Chouser	Before understanding what was going on there, Clojure script was doing (+ 1 (/ 5 2)) -> "15/2"
11:23	Chouser	that's close enough, right?
11:23	rhickey	:)
11:29	Chouser	unless the todo list is going to be terrbily long or have high turnover, you might just keep a text file in clojure-contrib, or a message pinned to the top of the google group.
11:33	Lau_of_DK	No insights into my paste? :)
11:36	Chouser	Lau_of_DK: I've got it loaded in a repl, but haven't learned anything helpful yet.
11:39	rhickey	Clojure's ToDo list: http://richhickey.backpackit.com/pub/1597914
11:40	rhickey	I didn't realize the thing I was using had public viewing ^^^
11:40	Lau_of_DK	Chouser, thanks, its good to know you're on it ! :)
11:40	Chouser	rhickey: heh.
11:40	drewr	rhickey: Nice!
11:40	rhickey	I'll split off requests for implementations into it's own list
11:42	rhickey	its
11:43	Chouser	ah, that's good. Now I can know when to stop bugging you about patches I've sent in. :-)
11:44	drewr	Looks like LinkedBlockingQueue will do exactly what rhickey described.
11:56	drewr	http://bc.tech.coop/blog/081023.html
11:57	drewr	Bit of JSwat example at the end.
12:13	H4ns	another common lisper on the band wagon :)
12:16	Chousuke	Lau_of_DK: I think I found the problem
12:17	Chousuke	at least, I managed to modify the algorithm so that it produces 142857 which seems to be the correct answer.
12:18	Lau_of_DK	Can you enlighten me and annote ?
12:19	Chousuke	Lau_of_DK: your recur in find= seems incorrect
12:19	hircus	Lau_of_DK: hiyas
12:20	Lau_of_DK	hircus, hey man :)
12:21	Lau_of_DK	Ok Chousuke, please annote so that I can try and understand
12:21	hircus	tried #76 yet?
12:21	Lau_of_DK	Not yet
12:21	Lau_of_DK	I'm almost done with < 50's
12:21	hircus	pretty much the SICP count-change problem, but with the number of choices being high enough that it's impossible to brute-force it
12:21	Chousuke	after the first iteration seqs becomes ((2 3 4 5 6) (2 4 6 8 10 12) (3 6 9 12 15 18)), so you keep dropping the first element from the first sequence and sorting them until all the firsts match
12:21	hircus	ah, you're doing it sequentially; I just scatter-shot the problems :)
12:22	Chousuke	which in this case happens at 6 :/
12:22	Lau_of_DK	oh
12:22	Lau_of_DK	oh yes I see, its only the first seq that I (rest)
12:22	Lau_of_DK	How did you cure it?
12:23	Chousuke	I did (recur (map rest seqs))
12:23	Lau_of_DK	yea Im trying that now
12:24	Lau_of_DK	Thanks Chousuke, I really appreciate you putting in the work, I had starred myself blind on it
12:24	Lau_of_DK	How long did it take to compute on your system ?
12:24	Chousuke	hmm now I got a stack overflow error.
12:24	Lau_of_DK	How did you reach 142857 ?
12:26	Chousuke	apparently the sorting is needed to keep it from overflowing the stack
12:27	Lau_of_DK	Yea, for some reason, otherwise its quite redundant
12:27	Lau_of_DK	Mine is still computing
12:27	Chousuke	really weird
12:28	Chousuke	is sort destructive?
12:28	Chouser	no
12:29	Chousuke	well what
12:29	Chousuke	lisppaste8: url
12:29	lisppaste8	To use the lisppaste bot, visit http://paste.lisp.org/new/clojure and enter your paste.
12:31	digash`	http://www.google.com/trends?q=clojure&ctab=0&geo=all&date=ytd&sort=0
12:32	lisppaste8	chousuke pasted "weirdness" at http://paste.lisp.org/display/69058
12:32	digash`	i like this trend
12:33	Chouser	digash`: nice. This will be fun to watch: http://www.google.com/trends?q=clojure%2C+lisp
12:33	Chousuke	I also modified n-seq to be just (iterate #(+ % n) n)) but the rest is the same
12:35	Lau_of_DK	Chousuke, you really should anote, instead of pasting a new, gives better overview
12:35	Chousuke	ah right, forgot the annotation capability.
12:36	hircus	Lau_of_DK: oh wow, Petite Chez Scheme actually computes #76 by brute force
12:36	hircus	trying to work out a cleaner solution
12:37	Chousuke	but still that doesn't make sense. :/
12:37	Chousuke	why does a let affect recur so that it doesn't overflow the stack?
12:38	danlarkin	certain forms can become reentry points or whatever
12:38	Lau_of_DK	hircus, looking forward to seeing it
12:38	danlarkin	I don't know if let is one of them, though
12:39	hircus	Lau_of_DK: #78 is very similar and can't be brute-forced, so yes, will have to do it :) I just need pen and paper to work it out
12:40	lisppaste8	Chousuke annotated #69055 with "Weirdness" at http://paste.lisp.org/display/69055#1
12:40	Lau_of_DK	hircus, have a look at that paste
12:41	Lau_of_DK	Chousuke, I should have asked, sorry, I pasted in your name, a complete copy of your other paste
12:41	Chouser	let is not a recur target. I can't figure out what's going on.
12:41	hircus	weird!
12:41	Lau_of_DK	Chousuke, that one where you say "this works", doesnt return on my system, I dont get a reply
12:42	hircus	s1 & etc were not even used at all?
12:43	Lau_of_DK	no, not in Chosukes attempt
12:43	hircus	..
12:43	Chousuke	Lau_of_DK: it does on mine
12:43	Lau_of_DK	really, what is your secret?
12:44	Lau_of_DK	because using your exact code... does not return :)
12:44	lisppaste8	Chousuke annotated #69055 with "my n-seq" at http://paste.lisp.org/display/69055#2
12:44	Chousuke	Lau_of_DK: try with that.
12:45	hircus	how should n-seq.. oh
12:46	Lau_of_DK	oh, sorry me
12:46	Lau_of_DK	silly me
12:46	Lau_of_DK	even
12:46	hircus	Lau_of_DK: was your n-seq eagerly-evaluating?
12:46	Lau_of_DK	no, it was lazy
12:46	hircus	so.. still not sure what was the problem
12:46	Lau_of_DK	oh wait
12:46	hircus	sort will force evaluation, right?
12:46	Lau_of_DK	typo - I was fiddling with it a minute ago, corrupted it
12:47	Lau_of_DK	sort (in this case) only deals with the head
12:47	hircus	that's the only difference I could think of
12:47	hircus	yes, but sort forces evaluation of the entire sequence
12:47	lisppaste8	Chouser annotated #69055 with "also works" at http://paste.lisp.org/display/69055#3
12:47	Lau_of_DK	anyway, the Euler is solved, but it raises a question about stack-usage
12:47	Chouser	hircus: I think that proves your hypothesis.
12:48	hircus	Chouser: the last paste? looks like it
12:48	Chousuke	so it was being too lazy? :/
12:48	hircus	a bit surprised that lazy sequences are put on the stack, but hey
12:48	Lau_of_DK	Chouser, you run doall on infiniate sequences?
12:48	Chouser	this isn't the final answer.
12:48	Chouser	Lau_of_DK: no
12:49	Chouser	don't run sort on infinite seqs either. :-)
12:49	Lau_of_DK	Americans...
12:50	hircus	seems easier to do #52 by converting to strings, anyway
12:50	Chousuke	(map n-seq [1 2 3 4 5 6]) is a finite sequence of infinite sequences; the doall just forces the n-seq to be called.
12:50	Lau_of_DK	hircus, can you run it in 2 secs with strings ?
12:50	hircus	for a number, convert to a string then to a seq of chars then sort
12:50	hircus	aha, no
12:50	Lau_of_DK	Chousuke, OH!
12:51	Lau_of_DK	I didnt know that
12:51	hircus	actually, I can
12:51	hircus	0.174secs in Python
12:51	Chousuke	removing the doall from find= and putting it in the find= call like so (find= (doall (map n-seq [1 2 3 4 5 6])) will work
12:51	hircus	start it at 125874, though, no need to start from 0 :)
12:52	Chousuke	whoops, missing a parenthesis
12:52	Chousuke	I wonder if irssi has a syntax highlighting plugin :/
12:54	Hun	hmm... one could use emacs rcirc + multi-major-mode for this
12:56	Chousuke	this stack overflow problem looks like something that might bite again if there's a lot of laziness :/
12:56	Lau_of_DK	Chousuke, I believe youre right
12:57	Lau_of_DK	I had to take off, but I'd like to thank everybody who helped bring me up to speed, youve been a fantastic help!! Have a good evening
13:01	gnuvince	Has it been discussed here how to translate the "classical" Haskell solution for sieve of erasthesomethings to Clojure? In Haskell it's usually: let { primes = sieve [2..]; sieve (x:xs) = filter [n \| n <- xs, n `mod` x /= 0] }
13:09	gnuvince	hmmm
13:09	gnuvince	are LazyCons really lazy?
13:24	leafw	can one make a function that takes multiple sets of arguments (easy). but where some of these are private? I.e. [x] is private, but [x y] is public.
13:25	gnuvince	leafw: I don't think you can. Use a nested function for that.
13:25	leafw	ok
13:25	leafw	thanks
13:26	leafw	but aren't nested functions public? Perhaps defined only in a let, I guess
13:27	leafw	oh, or with #^{:private true}, I guess
13:34	leafw	can't a function refer to itself within its own declaration?
13:35	lisppaste8	leafw pasted "fibonacci" at http://paste.lisp.org/display/69060
13:36	leafw	first one works, second fails to compile
13:36	wwmorgan	leafw: try using a named anonymous function
13:36	leafw	sorry: named anonymous function?
13:37	leafw	isn't that what the let is doing in this casE?
13:38	lisppaste8	wwmorgan annotated #69060 with "compiles" at http://paste.lisp.org/display/69060#1
13:38	gnuvince	leafw: let don't allow recursion.
13:39	leafw	thanks people. That (fn this [...] ) is new to me.
13:57	Hun	leafw: you could do it like the second one by implementing the y-combinator
13:59	gnuvince	@url
13:59	gnuvince	lisppaste8: url
13:59	gnuvince	lisppaste8: url?
13:59	lisppaste8	To use the lisppaste bot, visit http://paste.lisp.org/new/clojure and enter your paste.
13:59	lisppaste8	To use the lisppaste bot, visit http://paste.lisp.org/new/clojure and enter your paste.
13:59	leafw	Hun: show me
14:00	gnuvince	leafw: did you try the infinite fib list solution?
14:00	lisppaste8	gnuvince pasted "How's this implementation of rests?" at http://paste.lisp.org/display/69061
14:00	Hun	leafw: i don't have a running clojure on this machine, so this might not work
14:00	Hun	(defn y (fun)
14:00	Hun	(fn [& args] (apply fun fun args)))
14:03	lisppaste8	Chouser annotated #69061 with "Another "rests"" at http://paste.lisp.org/display/69061#1
14:04	leafw	Hun: haven't ever used the y-comb
14:05	leafw	've read about it, that's all.
14:05	leafw	your impl looks .. will trye
14:05	Hun	the basic idea is that the function gets itself as its first arg
14:05	Hun	which is what y does on the fn
14:05	Hun	end the function defines where to recourse
14:06	leafw	andinitial args to the fun are passed how?
14:06	leafw	trying
14:09	Hun	they are passed through to the function. that definition might not work, depending on how apply works in clojure
14:10	AWizzArd	Moin
14:57	lisppaste8	jochu annotated #69060 with "Using an infinite lazy seq" at http://paste.lisp.org/display/69060#2
15:38	leafw	woah : jochu, that was awesome.
15:39	leafw	although I don't understand it.
15:40	leafw	lazy-cat concats two sequences, but you give it an array [0 1] and then the result of a mapping that involves sums, but I don't see how it sums the right pair of numbers.
15:41	leafw	somehow, the lazy-cat is defining the fibonacci sequence itself, in abstract form. This is briliant, reads almost like prolog
15:42	Chouser	yeah, impressive. The summing is of each fib and fib offset by one (via rest)
15:45	duck1123	how can I retrieve just the doc-string of a function? (doc) prints it, but doesn't return anything and (meta) doesn't return it either.
15:46	wwmorgan	duck1123: (with-out-str (doc doc))
15:47	wwmorgan	also (:doc ^#'doc)
15:48	duck1123	that's what I wanted
15:48	duck1123	thanks
16:00	AWizzArd	rhickey: Thanks for your comments about Currying Rich. I still think we could do it, with something else instead of #(). Maybe �() or something like that.
16:02	Chouser	AWizzArd: I don't know how to type that thing.
16:02	duck1123	that's going to be hell to type
16:02	Chouser	And although it looks ok in the browser, in this window it just shows up as the rectangle used when a font doesn't have that glyph.
16:03	AWizzArd	you all still use this 1886 keyboard layout yes? ;-)
16:03	cemerick	� is option-6 on Macs, fwiw
16:03	AWizzArd	This qwerty stuff
16:03	AWizzArd	Shift 3 I guess on qwerty maybe?
16:03	Chouser	served me well so far
16:03	H4ns	AWizzArd: it is not ascii, forget it.
16:04	AWizzArd	H4ns: why not doing unicode? I would like to have greek symbols in my source. My keyboard layout can produce them so easily.
16:04	H4ns	AWizzArd: you certainly don't want things in the base language that only germans can type with reasonable effort
16:05	rhickey	I was thinking of something like this for apply/curry: #(@ + 5), where #(@ ...) means (fn [& args] (apply ... args))
16:05	AWizzArd	Well sure, and the � is just an example. It can be anything else that makes sense. My point is just: let us have currying.
16:05	rhickey	@ being special as first form in #()
16:05	duck1123	we should start using ? in code instead of #()
16:06	H4ns	AWizzArd: your point is: rhickey, implement currying! :)
16:06	rhickey	but not sure about more symbol overload
16:06	rhickey	currying is overrated
16:06	H4ns	i like partial application a lot, but i don't need no fancy syntax for that.
16:06	rhickey	#() is pretty neat as is
16:07	AWizzArd	H4ns: well yes, I showed my implementation of it in Google Groups. I just can't implement reader macros.
16:07	duck1123	rhickey: the doc-string for -> has a redundant 'macro' in it.
16:08	AWizzArd	!(rgb _ 123) or having the @ or $(..) or whatever.
16:10	rhickey	there's already partial and #(), this doesn't seem pressing
16:12	gnuvince	currying is, in my opinion, one of the two pillars of unreadable Haskell code.
16:12	rhickey	:)
16:12	Chouser	heh
16:13	gnuvince	the other is succinct function composition
16:13	gnuvince	Check the forums of Project Euler, especially answers from the French Jedai
16:14	gnuvince	it's 3 lines of nothing but function composition of curried functions with a bunch of curry, uncurry and flip thrown in for good measure.
16:18	AWizzArd	I see partial as not too useful. The whole idea behind currying is to have syntactic sugar, to save a few keystrokes. So, (partial ..) is too long imo.
16:29	duck1123	what is the difference between a var quote and a normal quote?
16:30	duck1123	nvm, I found it
16:35	Chouser	(partial foo) seems a _bit_ nicer than (fn [& x] (apply foo x))
16:36	Chouser	and even a bit nicer than #(apply foo %&)
16:48	meredydd	Chouser: Also, doesn't (partial) date from before the introduction of #(...)?
17:08	Chouser	meredydd: I think so
17:11	schwartzwald	what do clojurers think of scala?
17:11	schwartzwald	clojure is an alternative, not a replacement for java right?
17:12	Chouser	I came to clojure seeking refuge from Scala's type system.
17:12	kotarak	scala seems to be more verbose in syntax than Clojure or ML...
17:12	schwartzwald	or it would be a reasonable to write JAVA(enterprise)-stuff in clojure? i tried scala bu it felt pretty heavy and unflexible, like java
17:12	AWizzArd	Chouser: yes, but $(foo) is even nice than #(apply foo %&) or (partial foo)
17:12	schwartzwald	yes scala seemed great on paper but it didnt feel good
17:12	AWizzArd	Clojure is a functional programming language. It makes sense to have currying.
17:13	Chouser	schwartzwald: I don't know why you wouldn't be able to write whatever you want in Clojure. It's pretty practical.
17:14	kotarak	AWizzArd: How do you distinguish: (defn foo ([x] ...) ([x y] ...)) $(foo z)?
17:14	Chouser	kotarak: apply does that for you.
17:15	AWizzArd	app.. yes
17:15	Chouser	if you replace $(foo z) with (partial foo z)
17:15	kotarak	Chouser: I was asking for currying. When I curry, how do I decide which form to use?
17:16	AWizzArd	kotarak: can you be more specific?
17:16	kotarak	(foo z) is legal. (foo a b) is also legal. What does $(foo z) mean, the first or the curried second?
17:16	AWizzArd	btw, I want to replace $(foo z) with (fn [& args] (apply foo z args))
17:17	AWizzArd	if you want to curry away some earlier args you would do it this way: $(foo _ z)
17:17	AWizzArd	just read in google groups, it's explained there
17:17	AWizzArd	http://groups.google.com/group/clojure/t/36c77eec86a0930b
17:18	AWizzArd	I used #(foo _ z) in that posting, but rhickey gave good arguments why to leave #() untouched so far. Now I suggest to think about having some other character. And that could even be recycled for a later addon like an infix reader for math.
17:19	AWizzArd	We just need some other symbol than #. It could be a $ or a ! or maybe <foo _ z>.
17:20	AWizzArd	I would implement it myself as a reader macro, but at this point CLJ doesn't allow us to access the readtable, so read macros need to be written in assem... in Java.
17:20	wwmorgan	AWizzArd: you could implement it as a non-reader macro too, right?
17:21	AWizzArd	yes, and I did that, just click the link
17:21	AWizzArd	It's also not bad, but I think ($ < 5) is not as nice to read as $(< 5)
17:33	emacsen	rhickey, so, I've been reading about Lisp50, and here's the problem Clojure has. All the great language designers are weird looking. There's even a site my gf sent me to: Language designer or serial killer. You have to match the photo with the description. You look like a normal, regular (non-geek) man. Thus, I'm afraid, Clojure may be doomed to failure.
17:33	emacsen	;)
17:34	Hun	popcorn and tacos for everyone!
17:37	emacsen	Hun: It's mainly a joke. I actually disagree with McCarthy. Languages /do/ need a single face, at least in the beginning.
17:38	Hun	true. i also believe that anybody needs a big beard. not that i have one though :/
17:38	emacsen	beards are really optional. that's more a Unix thing
17:39	wwmorgan	http://blogs.microsoft.co.il/blogs/tamir/archive/2008/04/28/computer-languages-and-facial-hair-take-two.aspx The English really makes it hilarious
17:45	danlarkin	I wonder when I'll become a famous language designer
17:48	walters	the fact that matz grew a beard just for that article is awesome
19:29	blbrown	http://groups.google.com/group/clojure/browse_thread/thread/f07b1a70eab5f8e2 anyone have an answer for this one
19:34	Chouser	blbrown: you want that for all functions defined after a certain point? Or just certain functions?
19:34	blbrown	Chouser, ideally of them. And the ability to print when a function is called is just one example. E.g. I might want to time how long a function executes
19:38	blbrown	Chouser: going to leave me hanging?
19:40	Chouser	blbrown: I think it's possible, but it's hacking around at a level I don't have much experience with.
19:40	Chouser	so I'm trying some things.
19:41	shoover	What about using the ns-* functions to get all the symbols in a given namespace. You could test a symbol's metadata to see if it's a function, then rebind thread-locally using binding and set!. Of course, that will only hold as long as you're in the binding scope.
19:41	blbrown	they say in lisp, you can use macros to achieve what I want
19:41	blbrown	shoover: that is an idea
19:41	Chouser	shoover: ooh, that's better than what I'm trying.
19:43	shoover	Rich always mentions binding when people talk about logging and timing, so it should work
19:44	Chouser	yeah, now that you describe that, I think I may have seen code for it go by on the google group
19:45	shoover	blbrown: and you can wrap all that binding stuff in a macro, so there's your lisp way
19:45	blbrown	shoover: you have some code or examples I can look at. I will give you a reddit karma point if you code up something in 10 minutes
19:48	shoover	Chouser will beat me now that he knows what to do :)
19:49	Chouser	hehe
19:50	shoover	lisppaste8: url
19:50	lisppaste8	To use the lisppaste bot, visit http://paste.lisp.org/new/clojure and enter your paste.
19:50	lisppaste8	shoover pasted "wrapping an existing function" at http://paste.lisp.org/display/69085
19:50	lisppaste8	Chouser pasted "trace" at http://paste.lisp.org/display/69086
19:50	shoover	no macro there, but it shows the binding process
19:53	shoover	Chouser: nice, with the var-get and trace-fn
19:53	blbrown	If you have used ASM, I did it with asm (and obviously reflection) but I was also looking for the clojure way. http://asm.objectweb.org/
19:54	blbrown	Chouser, shoover: thanks guys
19:54	shoover	I thought there was something in the metadata to flag a fn, but I don't see it now that I look at my ^#'bar
19:55	Chouser	:arglists ?
19:56	shoover	yeah, that's close enough, as long as it doesn't have the macro flag
20:36	emacsen	anyone know if there's audio/video of lisp50?
20:37	rhickey	They recorded it, but I don't know that it's available yet
20:37	emacsen	k
20:43	lisppaste8	Chouser annotated #69086 with "trace namespace" at http://paste.lisp.org/display/69086#1
20:46	Chouser	blbrown: That's as far as I'll mess with it.
20:46	Chouser	I imagine you could make is so that the details of trace-wrap could be passed in.
20:48	blbrown	Chouser, that is cool, thanks
21:03	duck1123	is anyone here familiar with compojure
21:04	duck1123	I'm trying to figure out how I can create a folder under app/ and have a file in there named other than the folder's name
21:22	chrisdone	rhickey: what is the font used in your Clojure for Lisp Programmers presentation (up on Blip.tv)? it's gorgeous and I want it!
21:24	danlarkin	chrisdone: looks a lot like Monaco to me
21:28	rhickey	chrisdone: yes, monaco for the code
21:29	duck1123_	is it possible to have clojure files named other than the name of the last folder?
21:29	chrisdone	danlarkin, rhickey: thank you :-)
21:30	danlarkin	duck1123: it sure is
21:31	duck1123	I'm trying to set up my namespaces for compojure, but it keeps wanting me to name it the same as the folder name
21:31	crathman	since the wiki says that sicp is not optimal for learning clojure, figured I'd be a contrarian.... :-)
21:32	crathman	chapter #1 has been translated to clojure - http://www.codepoetics.com/wiki/index.php?title=Topics:SICP_in_other_languages
21:33	duck1123	otherwise I get: Could not locate Clojure resource on classpath: mycyclopedia/view/view.clj
21:33	danlarkin	duck1123: having not used compojure I can't comment on any naming scheme it enforces
21:33	danlarkin	duck1123: but I can say the limitation isn't one imposed by clojure itself
21:33	duck1123	I don't think it really imposes anything other than what clojure does
21:35	duck1123	the wiki pretty much says to do the same thing: Now we have to create a file in the classpath with the filename "example/ourlib/ourlib.clj".
21:36	danlarkin	well I've been using files that are named differently than their containing directory, but perhaps I'm doing things different
21:37	duck1123	do I have to explicitly add the folder to the classpath, or do you happen to have an example?
21:37	duck1123	I noticed that clojure.contrib uses the same pattern
21:50	Chouser	naming the .clj the same as its folder allows the .clj to be loaded via the ns macro, require, use, etc.
21:51	duck1123_	so if I wanted to name it something else, I couldn't use the ns macro
21:52	Chouser	your file could still use ns, but nothing else could load your file using ns.
21:52	duck1123_	so how would I load it? That may almost be acceptable in this very limited senario
21:53	Chouser	you could use load or load-file
21:53	duck1123_	this file would only ever be loaded by one other file, I would go the proper route for anything else
22:25	ericthor	anything change on the gen-class front recently? I have a clojure gen-class extending a java class. I have a mypackage/ClassName/ClassName.clj...
22:26	ericthor	and the function names are (defn ClassName-extendedClassFunc[this])
22:26	ericthor	I can create an instance of the class but when I call any function I'm getting an AbstractMethodError...this used to work?
22:30	Chouser	was it working since the fn names changed to ClassName-fnName?
22:32	ericthor	Chouser: it worked as fn names are classname-fnnames
22:32	ericthor	Chouser: has that changed since?
22:34	ericthor	Chouser: might be time to redo my genclass stuff...going to turn in. Thanks for the help
22:34	ericthor	Chouser: I probably just have some out of sync clojure stuff
22:35	Chouser	There were changes to genclass in August, but none since.
22:51	larrytheliquid	if i have a map that has a certain key, and a function that takes a parameter that would ideally be the same name as the map key, is there a convention to distinguish the two?
22:51	larrytheliquid	ie: description vs description-param
23:02	Chouser	I don't think I understand. It's common to use keywords for map keys.
23:03	Chouser	does that help?
23:06	larrytheliquid	say i have something like (defstuct my-data :description), and then (defn do-something [description] ... )
23:07	larrytheliquid	inside do-something description would shadow the description method in the struct
23:09	Chouser	ah, for structs!
23:10	larrytheliquid	ah nevermind, i didn't realize that the symbol in the struct :description would be part of the method name too
23:10	larrytheliquid	so no conflicts
23:10	Chouser	um, no convention I'm aware of.
23:10	larrytheliquid	the colon*
23:10	larrytheliquid	the colon takes care of the difference
23:11	Chouser	ok, good.
23:14	Chouser	I can't get definline to work. Anyone know how to use it?
23:22	duck1123	has anyone here managed to get slime working with compojure?
23:23	duck1123	I can get standard clojure working, sbcl works, but I keep getting that stupid progn error when I try to use compojure