#clojure – 2008-12-16

2008-12-16

00:07	arohner	is the github mirror of clojure contrib working for anyone else?
00:07	arohner	it says the last commit is dec 7
02:38	Lau_of_DK	Top of the morning gents
03:07	slangan	http://www.computersight.com/Programming/Five-Strangest-Programming-Languages.397205
03:07	slangan	LOLCODE ^^ so friggin funny
03:07	slangan	http://www.computersight.com/Programming/Five-Strangest-Programming-Languages.397205
03:07	replaca	yeah, that was a big reddit today
03:08	slangan	oops
03:08	slangan	"IM IN YR LOOP - IM OUTTA YR LOOP"
03:08	slangan	HAI
03:08	slangan	CAN HAS STDIO?
03:08	slangan	VISIBLE "HAI WORLD!"
03:08	slangan	KTHXBYE
03:08	replaca	yeah, but it needs a graphics subsystem that shows pics of your LOLCATs while the prog runs
03:12	zakwilson	lolcode was on reddit months ago.
03:15	ivan	slangan: http://www.esolangs.org/wiki/Language_list
04:02	AWizzArd	When I have a string filled with xml, how can I parse it?
04:02	Lau_of_DK	See Zip-filter
04:03	AWizzArd	in the clojure.xml package?
04:03	Lau_of_DK	(xml-> (xml/Parse "xml-file.xml") :root :child [:element "Custom search"])
04:03	AWizzArd	well yes, but (clojure.xml/parse ...) does not work on strings
04:04	AWizzArd	it wants a file or a url
04:05	Lau_of_DK	Thats where Zip-filter comes in
04:05	Lau_of_DK	(zip/xml-zip (xml/parse "file.xml"))
04:05	AWizzArd	in what package can I find it?
04:05	Lau_of_DK	Contrib somewhere, Chouser wrote it
04:05	AWizzArd	yeah, only that I don't have a file
04:05	Lau_of_DK	huh?
04:06	AWizzArd	I have a string filled with xml.
04:06	AWizzArd	If it were a file or a url I would use clojure.xml/parse
04:06	Lau_of_DK	As I recall there's also a func which takes a string
04:07	AWizzArd	this is what I am looking for :-)
04:07	Lau_of_DK	infact, doesnt (zip/xml-zip ) do that?
04:07	AWizzArd	it takes a string s, but only returns [s nil]
04:08	Lau_of_DK	(defn parse-str [s]
04:08	Lau_of_DK	(zip/xml-zip (xml/parse (new org.xml.sax.InputSource
04:08	Lau_of_DK	(new java.io.StringReader s)))))
04:09	albino	parse-str sounds like it parses a string :)
04:09	AWizzArd	yes
04:09	AWizzArd	but it's not included I guess?
04:10	Lau_of_DK	Im not sure :)
04:10	AWizzArd	I mean, you just wrote it yourself, right?
04:10	Lau_of_DK	No I found it in the bottom of zip-filter.clj, under examples, commented out :)
04:10	Lau_of_DK	I think its a little helper Chouser wrote
04:11	AWizzArd	ic
04:17	AWizzArd	good, works, thanks
04:22	wipewindows	Can I haz purpose with life K thanks?
04:27	jdz	slangan: such purposes are hard to find. and they are not in this channel. kthnxbye.
05:39	hiredman	clojurebot: sicp?
05:39	clojurebot	sicp is http://www.codepoetics.com/wiki/index.php?title=Topics:SICP_in_other_languages:Clojure:Chapter_1
05:40	hiredman	clojurebot: sicp is also <reply>those guys are such dorks
05:40	clojurebot	Ik begrijp
05:56	AWizzArd	clojurebot: max users?
05:56	clojurebot	No entiendo
05:56	AWizzArd	sehr gut
05:59	hiredman	clojurebot: max people
05:59	clojurebot	max people is 116
06:03	AWizzArd	is that number (user-) overwritable?
06:03	hiredman	yes
06:03	AWizzArd	closurebot: max people is 4
06:04	hiredman	nice try :P
06:04	AWizzArd	Can you please lock this?
06:05	hiredman	why?
06:05	AWizzArd	to be able to trust this number (because it inherits trust in you)
06:08	jdz	what is max people and why would anybody want to trast such a number?
06:08	jdz	*trust
06:09	hiredman	jdz: it stores the max people clojurebot has seen in the channel
06:09	hiredman	I dunno why someone would trash it, and I am not sure that I care if they do
06:11	jdz	max as in "highest number of people present at one time" or "how many [different] people have visited the channel"? (i assume it counts stats for this channel ;)
06:11	hiredman	it doesn't really do stats
06:11	AWizzArd	at the same time
06:11	hiredman	jdz: max at any one time
06:12	jdz	well, i don't see much use of this number if it does not reset daily or weekly
06:12	jdz	and if it does not store the history
06:12	hiredman	shrug
06:13	jdz	except for entertainment reasons
06:15	AWizzArd	Hi black
06:15	blackdog_	hi
06:52	slangan	how do you use databases in clojure?
06:52	blackdog_	clojure.contrib.sql is a good place to start
07:07	AWizzArd	slangan: you have your own namespace, such as (ns com.slangan (:require (clojure.contrib [sql :as sql]))) and then in that namespace you can say (sql/with-connection ...) and so on.
08:05	wipewindows	how do I pull contrib?
08:18	aperotte	wipewindows: contrib is hosted on sourceforge, are you asking for the svn address?
08:20	aperotte	has anyone noticed that you get different behavior when using (load-file ...) versus calling each form in a file yourself in a repl?
08:33	clojurebot	svn rev 1161; refactored Comparator into superclass of functions only
09:19	clojurebot	svn rev 1162; EPL in header
10:03	aperotte	hello all, can anyone think of why some of the forms in a file might not be evaluated when using (load-file ...). If I load the file into emacs, select the contents and evaluate region, they all get evaluated.
10:05	Chouser	none of them get evaluated with load-file?
10:06	aperotte	no, all of the def's get evaluated
10:06	aperotte	and the defn's
10:06	aperotte	but then I call a few of the defined functions
10:06	aperotte	they don't get run for some reason
10:07	Chouser	can you trim it down to a single defn and a single call?
10:07	aperotte	I'll try, give me a few
10:11	slangan	how do I install contrib? do I just place it in some folder and then import it?
10:13	hoeck	slangan: yes, or you build a jar with ant
10:13	hoeck	and import that
10:14	rhickey	svnsync-ing Clojure to Google Code - taking forever
10:17	aperotte	Chouser: It's going to take me some time to trim it down, I'll come back once I can isolate the problem
10:18	Chouser	aperotte: ok. for what it's worth, the only thing I can think of is that the namespace var ns may get pushed/popped for a load-file
10:18	Chouser	...but I can't think of how that would break anything in your case
10:25	shoover`	rhickey: whoa, never saw lisp/clojure.lisp before
10:26	aperotte	Chouser: hmm ... ok, I'll keep that in mind while testing
10:27	rhickey	shoover`: doing some archaeology?
10:27	shoover`	when I went to the google project, that's how far along the sync was
10:27	rhickey	ah
10:28	rhickey	taking only slightly less time to sync than to write from scratch...
10:29	shoover`	thinking in Common Lisp, Clojure, .NET and JVM simultaneously must've been fun
10:29	rhickey	shoover`: yeah
10:30	Chousuke	hm
10:31	Chousuke	I guess teh move to google code means I'll have to reclone clojure... I hope GC will at least be faster than sourceforge :P
10:32	Chouser	browsing svn via the web is much faster at google code. fast enough to be usable even.
10:34	Chousuke	google code is definitely superior to sourceforge.
10:35	Chousuke	still, I keep wishing there was an official mirror using some DVCS :)
10:35	rhickey	Chouser: yes, everything about gc's web interface is so much faster
10:36	rhickey	... rev 370 ... fourth restart ...
10:36	Chousuke	I wonder if there is a way to get check-in notifications for the SVN repo in google code via some google api.
10:36	Chousuke	that way you could have an automatically updated git/mercurial/whatever clone of it.
10:37	Chousuke	RSS might be good enough.
10:39	Chouser	why push when you can poll, right? :-P
10:40	rhickey	Looks like I can setup an address for commits and one for issue changes
11:06	rhickey	http://groups.google.com/group/clojure-commits
11:06	Chouser	ah, nice idea.
12:14	rhickey	200 revs left ...
12:14	RSchulz	The full commit history is being replicated at the GC repo?
12:14	rhickey	I hope so
12:21	Chouser	it looks that way
12:26	RSchulz	When you say "it looks that way" are you seeing the commits on the feed at the foregoing link? 'Cause I'm not.
12:26	rhickey	RSchulz: they're not new commits, so I wouldn't expect them there
12:26	RSchulz	They have a special "import an existing SVN repository" capability?
12:27	rhickey	RSchulz: yes, a one-shot thing
12:27	RSchulz	Cool.
12:27	triddell	I can see the various revisions and view the diffs etc.
12:27	rhickey	one multi-hour extravaganza apparently
12:28	triddell	at 1055 and climbing
12:28	rhickey	maybe we shouldn't fiddle around in there too much until it finishes?
12:28	Chouser	right, not at the feed, but by examining the browsable svn repo I can see old versions of files.
12:28	triddell	np :-) ... that's exactly how I'd feel
12:29	rhickey	final lap...
12:36	RSchulz	On the lighter side, here's an IM I just sent to a Lisp programmer buddy of mine: Clojure keeps getting cooler. I can sense where this is headed. I'm going to end up in a state where writing Java makes me feel dirty.
12:37	rsynnott	irritated is more common than dirty, I suspect
12:45	zakwilson	I feel dirty when I have to use some Java library that requires a lot of mutation (e.g. constructors that don't take reasonable args, requiring the use of setters)
12:47	rhickey	svn checkout http://clojure.googlecode.com/svn/trunk/ clojure
12:47	rhickey	have at it
12:48	rsynnott	yay! Non-incredibly-slow svn :)
12:48	rhickey	http://code.google.com/p/clojure/source/browse/
12:49	rhickey	http://code.google.com/p/clojure/source/list
12:51	gnuvince	You changed the license?
12:53	rhickey	gnuvince: yes, to EPL a couple of days ago, to facilitate this move - successor to CPL
13:00	Chousuke	heh
13:00	Chousuke	git cloning the new repo now. it's still low, but way faster than sourceforge :P
13:00	Chousuke	slow*
13:04	zakwilson	clojurebot: svn?
13:04	clojurebot	svn is https://clojure.svn.sourceforge.net/svnroot/clojure/
13:05	zakwilson	clojurebot: svn is http://code.google.com/p/clojure/source/checkout
13:05	clojurebot	Ik begrijp
13:05	Chousuke	five minutes and already half done. this is not so bad after all
13:10	alphazero	clojurebot: svn is http://clojure.googlecode.com/svn/trunk/
13:10	clojurebot	Roger.
13:11	alphazero	URL: http://clojure.googlecode.com/svn/trunk
13:11	alphazero	Repository Root: http://clojure.googlecode.com/svn
13:11	alphazero	Repository UUID: a41a16f3-9855-0410-b325-31a011a03e7c
13:11	alphazero	Revision: 1162
13:11	alphazero	Node Kind: directory
13:11	alphazero	Schedule: normal
13:11	alphazero	Last Changed Author: rhickey
13:11	alphazero	Last Changed Rev: 1162
13:11	alphazero	Last Changed Date: 2008-12-16 09:10:56 -0500 (Tue, 16 Dec 2008)
13:13	Chouser	Chousuke: surely there's a way to use my existing git repo and just retarget the upstream one.
13:14	duck1123_	Chouser: I would think that git-svn wouldn't like that unless they were actually the same repository, just moved
13:15	Chousuke	Chouser: probably, but... my reclone just finished :)
13:15	Chousuke	if you have local modifications I guess you need to export them as patches :/
13:23	RSchulz	Well, for us readers-only, that was completely painless. I did a little switcharoo with directories after the check-out, copied over my src/Clojure.iml (not to be confused with Rich's clojure.iml!) and voila! Even IDEA didn't mind.
13:39	rsynnott	rfgpfeiffer_: they differ only by capitalisation?
13:39	rsynnott	sorry, RSchulz
13:39	RSchulz	I was unaware of Rich's when I set up my IDEA module. But mine's also in the src/ subdirectory while Rich's is at the top.
13:39	RSchulz	Not that it matters, mine's never going to leave my system.
13:47	RSchulz	Is Clojure-Contrib migrating to GC, too?
13:48	Chouser	I think it will, but I suppose it has to be compeletely switched over to EPL first.
13:51	Lau_of_DK	Good evening good folk
13:56	zakwilson	Good day, Lau_of_DK.
13:57	zakwilson	If you'll recall that file format we were talking about a few days ago, it's even more bizzare than I thought.
13:57	Lau_of_DK	I remember, what did you find ?
13:59	zakwilson	The official editor software generates files that make sense (parameter_id in one file matches parameter_id in the other), but the nearly 400 device files supplied as a downloadable package do not.
14:00	zakwilson	The official editor and the lighting controller can read and use these files.
14:00	Lau_of_DK	Sounds a little unintuitive, isnt this documented somewhere?
14:01	zakwilson	So I can make a working editor that will produce working files, but I cannot edit the files provided by the vendor.
14:02	zakwilson	Documented? Ha!
14:02	Lau_of_DK	Is the two-way thing important in your situation ? I remeber you want to provide a single-format solution to light-shows?
14:05	zakwilson	It's not important for that goal, but I want to start by making an editor for a single file format, and it would be nice if it's fully functional.
14:06	Lau_of_DK	Maybe you'll be the guy who writes the one Lamp to rule them all! :)
14:06	zakwilson	I actually have the controller in question and the provided device editor is horrible. It's slow, unstable and only runs on Windows.
14:06	zakwilson	I intend to release the replacement editor as open source, and use it as the basis for me one editor to rule them all.
14:07	Lau_of_DK	Sounds charming, but its good that you get some RE experience, thats always fun
14:08	zakwilson	I'm not sure I want to glorify it by calling it reverse-engineering. Figuring out what labled fields in a CSV file mean isn't that hard.
14:09	zakwilson	Figuring out that some fields are generated by adding/multiplying other fields is a little harder... as is discovering that overflow of a signed int is part of the design.
14:09	rsynnott	zakwilson: on a machine of some particular word size, I assume? :)
14:10	Lau_of_DK	I read your previous statement as you wanting to dive into the controllers driver? The one you said was slow and unstable
14:10	sohail	zakwilson, maybe the thing to do is create your own format :-)
14:12	zakwilson	Getting in to the controller's software is beyond me right now.
14:12	zakwilson	I intend to create my own format, but that needs to be translated in to formats various controllers can read.
14:13	deklund	quick question: 'use' is not transative? (does not appear to be). I just want to verify... i.e. if I use on a ns, I don't get the libraries/namespaces that the used namespace references?
14:13	zakwilson	rsynnott: yes
14:13	zakwilson	it seems to be 32-bit
14:14	zakwilson	which means I should be able to rely on overflowing ints with Clojure's unchecked arithmetic.
14:14	RSchulz	deklund: I'd hope not! But seriously, no.
14:15	deklund	:) thanks
14:15	rsynnott	it'd probably work in 32bit mode on a 64bit machine
14:15	rsynnott	but if you had the source and built it 64bit, it would probably NOT work
14:15	RSchulz	zakwilson: In the x86_64 world, at least, 32-bit programs run just fine as is. They need their usual complement of dependent libraries in 32-bit form, but the hardware for x86_64 is a superset at the user level.
14:16	rsynnott	same with Ultrasparc, I think; when running a 32bit app overflows happen as you'd expect
14:17	zakwilson	That makes sense. I don't have an x86_64 machine yet. Oddly enough, I do have an Ultrasparc.
14:19	rsynnott	32bit software running on an x86_64 just sees an ordinary x86
14:19	rsynnott	no extra registers or anything :)
15:03	Lau_of_DK	(doc emit)
15:03	clojurebot	It's greek to me.
15:04	hiredman	only clojure.core
15:16	hiredman	actions sent to agents happen in order right?
15:18	RSchulz	hiredman: According to http://clojure.org/agents they do.
15:18	RSchulz	"Actions dispatched to an agent from another single agent or thread will occur in the order they were sent, potentially interleaved with actions dispatched to the same agent from other sources."
15:21	hiredman	excellent
15:24	RSchulz	hiredman: Is this the first you're using Agents? I wrote my first code for them yesterday and I gotta' say, I think they're very cool.
15:25	RSchulz	But I really wish I could figure out how to keep them from hindering shutdown via CTRL-D at the REPL.
15:25	RSchulz	Registering them as a JVM shutdown hook doesn't seem to work.
15:26	RSchulz	I should say, registering an execution of (shutdown-agents) via the JVM shutdown hook doesn't work.
16:47	Lau_of_DK	In which revision did doseq change to vector bindings?
16:50	RSchulz	Lau_of_DK: Since it's meant to mimic (for ...), it seems natural. Anyway, I never encountered it in another form.
16:51	Lau_of_DK	Mr. Schulz, it seems that the change was made after 1089
16:52	RSchulz	What binding form did it take before then? A list?
16:52	Lau_of_DK	(doseq i (range 10)
16:53	Lau_of_DK	(println i))
16:53	Lau_of_DK	1
16:53	Lau_of_DK	2
16:53	Lau_of_DK	3
16:53	Lau_of_DK	...
16:54	RSchulz	Ah. Much more limited than (for ...)'s capabilities, then?
16:54	Lau_of_DK	The purpose of the change was to allow for :when :while keywords
16:59	SimonAdameit	hi
16:59	SimonAdameit	How do I measure the size (length) of a collection?
17:00	hiredman	(count ...)
17:00	SimonAdameit	thanks!
17:00	SimonAdameit	I obviously searched for length :)
17:02	RSchulz	Keep in mind that doing so will force a lazy collection and will never terminate for an unbounded one.
17:02	Chouser	but is constant-time for a PersistentList
17:05	RSchulz	Chouser: All of them?
17:06	Chouser	all instances of PersistentList? yes.
17:07	RSchulz	I meant all subtypes, but I see it has none. Other implementations of IPersistentList do not have constant-time (count ...) behavior, do they?
17:10	Chouser	I don't think it's guaranteed, but right now the only other implementor of IPersistentList is APersistentVector, which also should be ableo to do count in constant time.
17:14	dmiles	was DotLisp and clojure expected to be almost the same syntax?
17:15	dmiles	http://code.google.com/p/opensim4opencog/source/browse/trunk/bin/test.lisp
17:15	hiredman	dmiles: http://dotlisp.sourceforge.net/dotlisp.htm <-- explains why the syntax might be similar
17:15	dmiles	oh cool
17:17	RSchulz	Chouser: I posted to the list, but I guess I could / should have just mentioned it here, but Atoms are missing from the type chart.
17:17	Chouser	RSchulz: hm! thanks.
17:25	gnuvince_	If send-off immediately returns, how come doing a send-off of 20 elements takes nearly 10 seconds?
17:26	Chouser	gnuvince_: because you're doing something else in your loop that takes nearly a half-second?
17:27	RSchulz	Or because as soon as you send a task off the thread assigned to the receiving Agent becomes active and runnable?
17:32	gnuvince_	Chouser: The loop just does the send-offs
17:35	gnuvince_	net.gnuvince.comics> (time (doseq [[comic a] comic-agents] (send-off a conj (try (fetch-comic comic) (catch Exception e nil)))))
17:35	gnuvince_	"Elapsed time: 23271.9988 msecs"
17:36	Chouser	gnuvince_: nope, that's a common mistake. send-off takes a function not a block of code.
17:36	gnuvince_	Chouser: that's what I do
17:37	gnuvince_	(send-off a conj (...))
17:37	Chouser	ooh, maybe send and send-off should assert their arg is a IFn
17:37	Chouser	gnuvince_: ah, good point.
17:38	gnuvince_	Unless the try/catch is executed before the send-off
17:38	Chouser	but you're still evaluating the arg (fetch-comic) before passing its return value to send-off
17:38	Chouser	right
17:38	gnuvince_	Which would actually make sense
17:38	Chouser	right
17:38	gnuvince_	ok
17:38	gnuvince_	Thanks
17:38	gnuvince_	I'll see what I can do
17:38	gnuvince_	Well
17:39	gnuvince_	While I'm here
17:39	gnuvince_	Here's the problem I want to solve: I want to fire up a bunch of threads and accumulate their results in a single ref
17:43	hiredman	make it a thunk, arg to the func you send to the agent
17:44	hiredman	clojurebot: haskell?
17:44	clojurebot	Yo dawg, I heard you like Haskell, so I put a lazy thunk inside a lazy thunk so you don't have to compute while you compute.
17:45	danm_	heh
19:26	aperotte	Chouser: I asked this morning about (load-file ...) versus evaluating each expression in a file at the repl. Are there concurrency issues that might lead to differences in how things might be evaluated in those two settings?
19:29	RSchulz	aperotte: I think it's a virtual certainty that what you're seeing is not about concurrency unless you're evaluating forms that directly or indirectly trigger threaded execution (Agents, e.g.)
19:31	Chouser	aperotte: does the problem go away when you trim it down?
19:32	aperotte	It's hard for me to trim it down because I have a bunch of definitions that build on one another
19:33	aperotte	I'm not using agents ... only refs
19:34	aperotte	Chouser: I tried toy examples, but I didn't have the same problem
19:35	aperotte	RSchulz: ok, even if I'm using a java library deals with threads and might lock?
19:35	RSchulz	The more so!
19:36	RSchulz	The bottom line is that logically (with sequential execution assumptions) there's no difference between (load-file ...) and one-by-one evaluating the forms in the loaded file.
19:37	RSchulz	The fact that you're seeing a difference and that you know you're (indirectly) executing explicitly threaded code strongly suggests that that code is not entirely thread-safe.
19:37	Chouser	aperotte: can you sprinkle println's through the file?
19:37	RSchulz	Is the pattern of execution (or the difference between the two modes of evaluation) repeatable? Or unpredictable / variable?
19:38	RSchulz	Chouser: Heisenbug territory!
19:38	Chouser	yep
19:38	aperotte	I haven't tried println's through the file because I know it gets to the last statement
19:38	aperotte	But it is completely repeatable
19:38	Chouser	I understand -- I'm curious if the first println's would execute or if none of them would.
19:39	aperotte	ok, I'll give it a try
19:40	Chouser	RSchulz: I'm not sure exactly what to do with atom in the graph
19:41	RSchulz	I don't know how it fits into the type structure. What's the problem?
19:41	RSchulz	aperotte: Are you running on a multi-CPU or multi-core system?
19:42	Chouser	when you use 'atom' it creates an instance of clojure.proxy.java.util.concurrent.atomic.AtomicReference$IRef
19:42	aperotte	RSchulz: I'm running on a single cpu, single core system
19:42	Chouser	I can add that to the graph, but AtomicReference$IRef doesn't strike me as a particularly useful name
19:43	aperotte	Chouser: all of the (println ...) statements sprinkled through my code work
19:43	RSchulz	What I did when I first started playing with your chart generator code was to add a predicate of my own to detect Obj / IObj, which had not been accommodated at that time in your code.
19:43	RSchulz	Then I associated that with the others in your big map of type predicates.
19:44	RSchulz	So even though there was no (obj? ...) in Clojure, my modification to your generator acted as if there was and the graph was generated accordingly.
19:44	RSchulz	The same should be possible with Atoms.
19:44	aperotte	Chouser: however, between two of the println statements I sprinkled exists some code that should take about 20 seconds to run, and the println's happen within 4 seconds of one another ... I'm very confused why there's a difference at all
20:02	Chouser	aperotte: wow.
20:03	Chouser	RSchulz: it's not a problem of the code, it's how the chart should look
20:03	Chouser	I suppose I could use the word 'atom' in lowercase and leave out the cryptic class name entirely
20:03	RSchulz	Yes, but the point is that you can influce that by faking a pair in the map between labels and type predicates.
20:04	RSchulz	...influence...
20:04	RSchulz	Actually, the only "faking" is of an (atom? ...) predicate.
20:05	gnuvince_	paste
20:05	gnuvince_	lisppaste8: paste
20:05	hiredman	lisppaste8: url
20:05	gnuvince_	lisppaste8: paste?
20:05	lisppaste8	To use the lisppaste bot, visit http://paste.lisp.org/new/clojure and enter your paste.
20:05	lisppaste8	gnuvince pasted "Looks okay?" at http://paste.lisp.org/display/72271
20:06	gnuvince_	Chouser: how does that look?
20:09	Chouser	gnuvince_: well, does it work? :-)
20:09	Chouser	gnuvince_: any particular reason you don't use the value from comics as the agent's state?
20:10	gnuvince_	It works
20:10	gnuvince_	Chouser: I don't really need the state of an agent
20:10	gnuvince_	I'm merely using them to launch new threads
20:11	Chouser	do you really want the fetch-comic call to re-run if there's contention on the ref?
20:11	gnuvince_	no
20:11	gnuvince_	I guess having fetching the value once is enough.
20:11	gnuvince_	s/having//
20:13	gnuvince_	So I'd better move out the try/catch out of the dosync?
20:13	Chouser	right. I think that will also lead you to a more "functional" definition fetch-comic.
20:14	Chouser	gotta run -- I'll be back later.
20:14	gnuvince_	See ya
21:35	RSchulz	Chouser: Perhaps the funkiness surrouding Atoms comes from the fact that they're Clojure proxies. See (defn atom) in .../core_proxy.clj
21:42	Chouser	RSchulz: yes
21:43	RSchulz	I don't know how that helps, but perhaps it points the way. Still, the use of a user-supplied (you're the user) atom? predicate seems like a workable hook.
21:43	RSchulz	You could also ask Rich for an atom? predicate in the Clojure core.
21:44	Chouser	no, I don't need anything like that.
21:45	Chouser	this is just about how to label the graph
21:45	RSchulz	Then I think my technique will work.
21:45	Chouser	all the other classes we care about have names. Ref, Symbol, etc.
21:46	Chouser	But what name should I give this thing? There is logical class that could be named Atom, but because it's a proxy class its name is not terribly useful.
21:47	Chouser	I'm looking now at adding "constructor" function names to the graph
21:47	Chouser	that would add things like 'hash-map', 'sorted-set' and such to the appropriate ovals. Then adding 'atom' to this new one would be consistent.
21:51	RSchulz	The name should just be Atom. The membership criteria would (for now) be (loosely speaking) (and AtomicReference IRef).
21:52	Chouser	no, there is no thing called Atom
21:54	RSchulz	(defn atom? [thing] (and (instance? clojure.lang.IRef thing) (instance? java.util.concurrent.atomic.AtomicReference thing)))
21:54	RSchulz	I know, but people will understand what an Atom (or "atom") is in the context of the graph.
21:56	RSchulz	Regardless, you should probably consult Rich about this so you can depict the class structure accurately.
21:57	Chouser	you don't think they'll be surprised when they write try to write an 'instance?' test and find there's no clojure.lang.Atom class?
21:58	RSchulz	Well, that's why there should be type-discriminating predicates for every distinct kind of entity in the core!
22:20	deklund	hi all... what am I missing here? (let [ #^{ :a 1 :b 2} x [1]]
22:20	deklund	(meta x))
22:21	deklund	returns nil
22:25	Chouser	deklund: the #^ reader syntax attaches meta to the symbol x at reader time.
22:25	Chouser	I think.
22:26	Chouser	you might want: (let [x (with-meta [1] {:a 1 :b 2})] (meta x))
22:27	deklund	chouser: thanks. I guess I need to stretch my mind about that 'read' time distinction... i am not yet getting it.. ( I am guessing this is something fundamental)
22:28	Chouser	perhaps -- I'm not sure I quite get it yet.
22:28	deklund	:) good to know
22:30	Chouser	deklund: http://groups.google.com/group/clojure/msg/919455504c57659e
22:32	deklund	I was just reading that... I guess the distinction is that the #^ reader macro assigns to a 'form' object
22:32	deklund	with-meta is more for runtime 'user' objects
22:32	deklund	sound plausible? warmer?
22:35	Chouser	maybe, but 'form' objects and 'user' objects aren't very different
22:36	Chouser	when read, your first example creates a symbol x with the meta-data you gave.
22:37	Chouser	the compiler looks in that hash for a :tag key for type hints. Macros could use that metadata.
22:37	Chouser	(I'm thinking this through out loud -- makes more sense to me each time I try)
22:38	deklund	:)
22:38	Chouser	once compiled, I don't think you can get to that symbol x anymore, though.
22:39	deklund	inherently, you are using it, though... so how would it be lost
22:39	deklund	?
22:39	Chouser	no, the compiler used it to produce bytecode. In the bytecode it's probably just a java local, not a Symbol object anymore.
22:40	hiredman	clojurebot: you in?
22:40	clojurebot	Gabh mo leithsc�al?
22:40	Chouser	rhicky's not here to correct me when I wander off the true path. :-/
22:40	deklund	so ... in that case, (let [ x #^{ :a 1 :b 2} [1]]
22:40	deklund	x)
22:41	deklund	is the second x a new symbol?
22:41	deklund	i thought they got interned... and x was not lost
22:43	Chouser	symbols are not interned in Clojure
22:45	Chouser	(identical? (symbol "x") (symbol "x")) ==> false
22:45	deklund	ahh... so the second x is considered a new form symbol
22:45	deklund	ok... neat (def #^{ :a 1 :b 2} x [1])
22:45	deklund	(meta x) returns => nil
22:45	deklund	but
22:46	deklund	(meta #'x) => {:file "NO_SOURCE_FILE", :b 2, :line 1, :a 1, :ns #<Namespace user>, :name x}
22:46	Chouser	right, in that case the meta is attached to the Var as well -- I'm trying to find where that happens.
22:47	Chouser	of course you can also (def x #^{:foo :bar} [1])
22:48	deklund	I get a compiler error on that one
22:48	Chouser	hm!?
22:48	deklund	i tried that switcheroo with the let form and got a compiler error too
22:49	deklund	java.lang.NoClassDefFoundError: clojure/lang/Compiler$MetaExpr (NO_SOURCE_FILE:1)
22:49	deklund	[Thrown class clojure.lang.Compiler$CompilerException]
22:49	Chouser	you build from svn?
22:49	deklund	last week
22:49	Chouser	did you "ant clean" before "ant"?
22:49	hiredman	both works here
22:50	deklund	i'll try the ant clean
22:50	deklund	and an svn up
22:52	deklund	yup.. mea culpa. I needed to do an "ant clean"
22:52	Chouser	I think this is where the code is produced to copy the metadata from the symbol to the var: http://code.google.com/p/clojure/source/browse/trunk/src/jvm/clojure/lang/Compiler.java#327
22:55	deklund	just to be sure... the metadata is being copied to var or to the value of the var?
22:57	deklund	I'm going to have study the java in depth..
22:57	Chouser	to the Var itself
22:59	deklund	ok. now that I got rid of the compiler problem
22:59	deklund	(let [ x #^{ :a 1 :b 2} [1]]
22:59	deklund	(meta x))
22:59	deklund	returns {:a 1, :b 2}
23:00	deklund	the switcheroo works...
23:01	deklund	in that case I could make this argument:
23:02	deklund	(let [ x #^{ :a 1 :b 2} [1]] (meta x)) returns ---> {:A 1, :b 2}
23:02	deklund	(let [ #^{ :a 1 :b 2} x [1]] (meta x)) returns ---> nil
23:02	deklund	(let [ #^{ :a 1 :b 2} x [1]] (meta 'x)) returns ----> nil
23:02	hiredman	correct
23:02	deklund	in the first case, the metadata is associated with object itself
23:02	hiredman	yes
23:02	deklund	in the second it's associated with the symbol x
23:03	deklund	but not it's evaluated object
23:03	hiredman	not the symbol
23:03	hiredman	the var
23:03	deklund	and in the THIRD... the second x is a new sybol
23:03	Chouser	hiredman: nope, no Var here
23:03	hiredman	but
23:03	hiredman	fine
23:03	deklund	var?
23:03	hiredman	I lose
23:03	deklund	ok
23:03	Chouser	:-)
23:03	hiredman	clojurebot: hiredman?
23:03	clojurebot	hiredman is a three-toed sloth
23:04	deklund	does this THIRD scenario seem plausible?
23:04	deklund	you said symbols are not interned, so that could explain the nil return
23:04	Chouser	hiredman: Vars are created by 'def', 'intern', 'with-local-vars', but not by 'let'
23:05	Chouser	deklund: I think so
23:05	Chouser	but we should be able to ask for the meta of the same symbol...
23:05	deklund	i would think so too
23:06	deklund	but as you said... (identical? (symbol "x") (symbol "x")) returns false
23:06	deklund	so there might be no way to get the same symbol
23:06	Chouser	right, but I mean the same symbol, not just a symbol with the same name...
23:07	deklund	yes
23:07	Chouser	yeah, I'm not getting it. still trying...
23:07	deklund	i think I'm closer
23:07	Chouser	(let [z 0] (meta '#^{:a :b} z))
23:08	Chouser	the ' quotes the meta and symbol together. Like:
23:08	Chouser	(let [z 0] (meta (quote #^{:a :b} z)))
23:09	deklund	oh goodness. :) now I'm more confused
23:09	Chouser	no no, stay with me!
23:10	deklund	i'll try
23:10	Chouser	we're using meta to ask for the meta of a quote symbol
23:10	Chouser	quoted symbol
23:11	deklund	ok.. i think i see where you're going
23:11	deklund	first off... i thought quote only worked on the form right next to it
23:11	Chouser	so the meta of the symbol itself, not of the value or of some other symbol with the same name
23:11	deklund	yes
23:12	Chouser	deklund: that's right, except the reader takes the #^ metadata annotation and the following symbol together
23:12	deklund	i see that... and the fact that the quote works on the 'form right next to it implies the metadata is part of the next form
23:12	Chouser	deklund: in other words, #^ is the one exception to ' ... I think.
23:12	Chouser	exactly
23:12	deklund	read time... it's becoming clearer
23:13	deklund	ok... i see what you did there.
23:13	Chouser	(macroexpand '(let [z 0] (meta '#^{:a :b} z)))
23:13	Chouser	the ' quotes the z which just happens to have had metadata attached to it already.
23:14	deklund	as attached by the reader
23:14	deklund	yes
23:14	Chouser	(binding [print-meta true] (prn '(let [z 0] (meta '#^{:a :b} z))))
23:15	deklund	i think i see the path to clarity
23:16	deklund	i wonder if there is a way to get to that symbol later
23:18	Chouser	you can get to it in a macro, but after that I doubt it.
23:18	deklund	chouser: excellent.. thanks for walking through that with me
23:19	Chouser	and thank you! I understand it much better now.
23:20	Chouser	(defmacro pm [x] (println x "has meta" (meta x)) x)
23:20	Chouser	let [z 0] (pm #^{:a :b} z))
23:20	Chouser	with, of course, a leading (
23:22	deklund	i see, we're in a different evaluative mode with macros
23:22	Chouser	right, the parameter x in pm is the actual symbol that the reader is handing us -- the instance of Symbol with the metadata that the reader attached.
23:23	Chouser	of course that's still a different z symbol than the one in let's vector.
23:23	deklund	yes
23:24	deklund	but there was still that var issue...
23:24	Chouser	what is that?
23:25	deklund	(def #^{:foo :bar} x [1])
23:25	deklund	(meta #'x)
23:25	deklund	i think the _value_ of the var is getting the metadata
23:25	deklund	is that not what the #' reader macro does?
23:25	Chouser	ah, no.
23:26	Chouser	if you (def x), then later when you say just x it does the dereference and gives you the current value there.
23:26	Chouser	...because in normal programs, that's what you want.
23:26	Chouser	saying #'x or (var x) is sorta preventing the deref and giving you the Var object.
23:27	deklund	ahh i misread the api... that makes sense
23:27	Chouser	you can call the 'get' method of the Var object to get it's current value.
23:27	Chouser	(.get (var x))
23:27	deklund	or (var-get) apparently
23:28	Chouser	well sure, if you want to use the "documented" and "supported" API
23:28	Chouser	:-)
23:28	deklund	:)
23:28	deklund	so as a Var object is interned, we can get at its metadata later
23:28	Chouser	yes!
23:28	deklund	not so with symbols
23:28	deklund	ok
23:28	deklund	por fin!
23:28	deklund	again thanks...
23:29	deklund	time to hit the sack and have meta dreams
23:29	Chouser	same here. good night