#clojure – 2009-05-19

2009-05-19

02:20	ccmtaylor	help keys
02:23	hiredman	(doc keys)
02:23	clojurebot	"([map]); Returns a sequence of the map's keys."
03:07	yangsx	/join #ucw
06:18	unlink1	Is there a better way of achieving #(Math/sqrt %) ?
06:20	unlink1	ah. (:use [clojure.contrib.math :only (sqrt)])
07:09	unlink	man, clojure really is nicer to use than scheme.
07:12	unlink	Though, I suppose that is unsurprising given the two languages' design philosophies.
07:16	hoeck	unlink: yeah, they only have the lisp-1 in common, i guess
07:17	hoeck	unlink: and clojure comes with batteries included, whereas scheme wants you to build your low-level datastructures and primitives by yourself
07:19	unlink	hoeck: I'm referring to simple things like (let ((x 1) (y 2)) (+ x y)), little niceties like inc/dec, loop/recur, stuff like that.
07:20	unlink	but yes, having reader-macro access to hash sets, hash maps, etc, is major win.
08:46	cgray	if i make a class on the repl using proxy, what would its name be if i wanted java to call it?
08:46	cgray	i have to pass the name as a string... kind of annoying
08:46	Chouser	you shouldn't rely on the name of the proxy class, really.
08:46	kotarak	Proxy doesn't make classes, it makes objects.
08:47	Chouser	you can print it out with (class (proxy ...)), and pass that if you want
08:47	cgray	okay, so i need to use gen-class?
08:47	kotarak	The object is of an anonymous class.
08:47	Chouser	but don't hard-wire that proxy class name into a .java source file.
08:47	kotarak	If you need a class...
08:47	cgray	ok, thanks
08:48	Chouser	kotarak: well, proxy does create a named class if there's not an appropriate one already. But it's wisest to treat it as anonymous.
08:48	Chouser	cgray: or gen-interface, and then proxy that. Or a write an interface in a .java and proxy that.
08:51	kotarak	Chouser: I see proxy to generate "an object which implements the given interfaces". It's like "new Runnable() { void run() { do.somethin(); } }" in Java. If I need a class, I would use gen-class.
08:54	unlink	What's the idiom for creating an object with methods? To pull an example from SICP... http://dpaste.com/45602/
08:56	Chouser	unlink: http://programming-puzzler.blogspot.com/
08:57	Chouser	oh, that's not a good way to link.
08:57	Chouser	http://programming-puzzler.blogspot.com/2009/04/adts-in-clojure.html
08:57	Chouser	there. you've got some options.
08:58	Chouser	I have no idea who Puzzler is, but that post is very good.
08:58	unlink	thanks, Chouser
09:02	Chouser	kotarak: what?
09:03	kotarak	This whole "secure" stuff. To hide the implementation. There is an API, a contract on what's allowed and how to use the stack. Follow it and your are fine. If you do Voodoo stuff with the internals.... Well. You wanted to do Voodoo stuff. Don't complain.
09:04	Chouser	ah, yes. I think it's almost never (maybe actually never) necessary.
09:04	cgray	is gen-and-load-class broken, or is there some other reason that it is commented?
09:05	Chousuke	It's broken and unnecessary
09:05	Chouser	There's a reason the open stuff is simpler to do in Clojure -- it's probably what Rich thinks is right.
09:06	kotarak	And decoupling the methods from the object is also a good idea, I think. (read "multimethods")
09:11	kotarak	puzzler is Mark Engelberg.
09:11	Chouser	ah, thanks.
09:12	kotarak	Somehow this post doesn't fit to his recent discussion on the list.
09:13	unlink	Well, there are disadvantages to the open style. It's certainly more verbose to use. (account-deposit account amount) vs. (account :deposit amount)
09:14	Chouser	you can probably put it in an account namespace, and probably have no conflicts (how many libs define "deposit")
09:14	Chouser	...then it would be (use '(myns.account :only [deposit])) once, and later just (deposit account amount)
09:15	Chouser	and/or use a multimethod
09:16	scottj_	Is there a way to have namespace.test and use namespace without putting it on the classpath?
09:16	Chouser	you can load any .clj file directly with load-file
09:17	scottj_	In more words, I have some small utilities, such as date-converter, and I just run them by passing date-converter.clj to java -cp clojure.jar clojure.main date-converter.clj. I'd like to put some tests in a separate file, and the namespace in that file will need to use date-converter, but I don't really want to modify the classpath.
09:18	unlink	I'd like a defmethod which implicitly split the arguments into first & rest, dispatched on first, and passed rest to the method impls
09:18	clojurebot	http://www.pigdog.org/auto/mr_bads_list/shortcolumn/1914.html
09:18	Chousuke	:P
09:19	unlink	In fact, every time I've used multimethods I've wanted that.
09:19	unlink	Maybe I'm thinking of multimethods wrong.
09:19	Chouser	unlink: you are free to write such a thing. should be easy. Have you read the Clojure book?
09:19	unlink	yes
09:20	Chouser	oh, I thought his multimethod examples were great. Showed some nice cases where you want multimethods dispatching on other than the first arg.
09:20	unlink	s/I'd like a defmethod which/I'd like the default semantics of defmethod to be to/
09:22	Chouser	oh.
09:23	Chousuke	out of curiosity, why?
09:23	unlink	hmm
09:23	unlink	I guess those wouldn't be ideal.
09:24	unlink	I suppose what I'd rather have is a shorthand for (fn [x & _] (PRED x))
09:26	unlink	ok, fine, (defmacro dispatch [pred] `(fn [~'x & ~'_] (~pred ~'x)))
09:26	Chouser	#(do %& (PRED %)) ...it's barely shorter, but much more cryptic -- would it suffice?
09:26	Chouser	har har.
09:26	chessguy_work	'mornin
09:26	Chouser	chessguy_work: hi
09:27	kotarak	unlink: (defmacro dispatch [pred] `(fn [x# & _#] (~pred x#)) is cleaner
09:27	unlink	Some might say that O:-)
09:27	chessguy_work	i've been doing some thinking about how to represent chess patterns in clojure
09:28	chessguy_work	i have my first sample pattern written, though there's nothing behind it
09:28	chessguy_work	http://paste.lisp.org/display/80490
09:28	Chousuke	hmmm... (defn dispatch-on-first [p] #(p (first &%))); (defmulti (dispatch-on-first class))
09:29	unlink	I actually didn't know about &% until just now.
09:29	chessguy_work	i'm thinking that i can macro that whole thing into a function which takes a position and returns either a map of bindings for the various variables or nil
09:31	Chousuke	chessguy_work: use a vector instead of the list, at least; ((foo) (bar)) looks like a function call.
09:32	chessguy_work	Chousuke, you mean as the parameter to pattern?
09:32	Chousuke	yeah.
09:32	chessguy_work	gotcha
09:33	Chousuke	also, what exactly do the (enemy "a") etc do?
09:33	chessguy_work	it's sort of "declaring" those "variables"
09:33	Chousuke	hmm
09:33	chessguy_work	meaning "there exists an enemy, who we'll refer to with the string "a"
09:33	chessguy_work	(enemy piece)
09:34	Chousuke	in that case, it might be better to do just [a :enemy, b :enemy] like let.
09:34	Chousuke	or however you represent your pieces.
09:35	chessguy_work	well ultimately this is going to return a map like { "a" :f7, "b" :e2 }
09:36	chessguy_work	saying, "this pattern matches the position if you take the piece on f7 to be "a",..." etc.
09:36	chessguy_work	so maybe i want [:a :enemy, ...] ?
09:37	Quiark	Hi.I have a list of items and need to update each of them, but the updating function needs to have access to the updates done so far. Something like (map fn data), but fn needs to see the most up-to-date version of the list. What would be the best way to do it?
09:38	chessguy_work	i want as much work as possible to be done with a macro here so that this is as close to the domain as possible
09:41	Chouser	Quiark: your fn needs access to the whole list?
09:41	liebke	Quiark: I'm thinking you'll need to loop/recur
09:41	Quiark	Chouser, yep
09:41	Chouser	Quiark: does it need to know which element it's on (by index or something) or just the value that it's processing?
09:42	Quiark	Chouser, the value is enough
09:42	Chouser	I think reduce will probably do it for you.
09:42	chessguy_work	Chouser, maybe something more like this: http://paste.lisp.org/display/80491
09:42	jdz	if i want to create my own exception classes i have to use gen-class facility, right?
09:43	Chousuke	chessguy_work: I think for the assertions you could use functions
09:44	Quiark	Chouser, I have a set of objects, with x,y coords and need to move them around and to check collisions (that's why I need the up-to-date list in the updating fn)
09:44	Chousuke	chessguy_work: that's going to be tricky to parse otherwise.
09:45	chessguy_work	Chouser, you mean for on and if-move ?
09:46	Chouser	Quiark: doing this the way you suggest will probably be O(n^2) and I imagine there are ways to do it faster.
09:46	Chouser	Quiark: though it's a fun little Clojure puzzle, so...
09:46	Quiark	Chouser, yes, i know, but that's not an issue, I just want to try something out
09:46	Chouser	ok
09:47	Quiark	(and try clojure along the way :)
09:47	Chousuke	(pattern [(declare [a :slider, b :enemy, c :enemy, line :rank-or-file]) (assert-on line #{a, b, c}) (if-move [b :off line] (attacks? a c))]
09:49	chessguy_work	interesting
09:49	Chousuke	though declare needs to be renamed :p
09:49	Chousuke	as it conflicts with core
09:50	Chousuke	unless you just look for the symbol name. :)
09:50	chessguy_work	ok, i'll send rich an email and make him change it
09:50	Chousuke	:D
09:50	chessguy_work	oh, you mean i need to rename mine? :)
09:51	Quiark	so I guess I need to process nth item, remove nth item, insert updated one and then move on to (n+1)th item
09:51	chessguy_work	i guess i'm still not getting something about the difference between a and :a
09:51	Chouser	Quiark: I do think reduce could be made to work, but liebke's suggestion to try loop/recur is a good one.
09:51	Chousuke	well, in the macro context, a is a symbol, :a is a keyword
09:51	chessguy_work	i wouldn't have guessed i could use a, b, c, etc. like that
09:51	Chousuke	traditionally, symbols are names for things that the user names.
09:52	Chousuke	:P
09:52	Chousuke	(as if clojure has much tradition yet)
09:52	clojurebot	clojure is like life: you make trade-offs
09:52	chessguy_work	well a is ultimately going to be a key in a map
09:52	Chousuke	well, yeah
09:52	Chousuke	you can convert it from a symbol to a keyword for that purpose
09:52	chessguy_work	so i would have guessed it needed to be a keyword
09:53	chessguy_work	ok
09:53	Chousuke	keys in maps can be anything
09:53	kotarak	Quiark: Chouser: Shouldn't (reduce (fn [up-to-date item] (conj up-to-date (update up-to-date item))) [] items) do the trick?
09:54	chessguy_work	cool. i love how little clojure syntax there is in that.
09:55	chessguy_work	almost everything in there is domain-specific
09:55	Chouser	hm, maybe. Does update need access to the tails?
09:56	Quiark	it needs all items, to check for collisions
09:57	Chousuke	chessguy_work: the input to your macro is an unevaluated data structure. you can require it to be anything.
09:58	Chousuke	of course, best for you is something that's easy for you to process
09:58	Chousuke	but that might not be the best for the user.
09:58	kotarak	(defn tail-seq [s] (lazy-seq (when-let [s (seq s)] (cons s (tail-seq (rest s)))))) (reduce (fn [up-to-date [item & tail] (conj up-to-date (update up-to-date tail item))) [] (tail-seq items)), something like that?
09:59	Chouser	,(take-while identity (iterate next [1 2 3 4]))
09:59	clojurebot	([1 2 3 4] (2 3 4) (3 4) (4))
09:59	Chouser	Quiark: there are the not-yet-updated values...
10:01	guinea	How cheap are agents? Would it be reasonable to make a spreadsheet where each cell is an agent?
10:01	Chouser	guinea: yes
10:01	guinea	sweet
10:01	chessguy_work	Chouser, in this case, i want to make these as easy as possible for the user, since there could be domain experts looking at this code
10:02	Chousuke	I'm already getting used to being called Chouser. I'm not even confused.
10:03	Chouser	Chousuke: And I'm learning to ignore the yellow highlights in my window
10:03	chessguy_work	oy
10:03	chessguy_work	sorry guys
10:03	Chouser	no, seriously, we're used to it.
10:03	chessguy_work	i didn't even realize you were both talking
10:05	choucroute	everyone who's cool has a nick starting with ch*
10:05	Chousuke	oh no, another chou
10:05	Chouser	sheesh
10:05	gnuvince	holy crap
10:05	chessguy_work	haha
10:06	Chousuke	chessguy_work: figuring out the interface is up to you; I don't know your full requirements or even what you're up to. Just remember that clojure has more than just lists, symbols and keywords that you can use in your DSL. vectors, maps and sets (didn't forget to mention them this time!) are fine too.
10:07	Chousuke	you could look at other DSLs for inspiration
10:07	Chousuke	:P
10:07	chessguy_work	Chousuke, yeah, i don't even really know the full requirements either. my main goal for this part is to make the description of precise chess patterns as absolutely readable to non-programmer chess players as possible
10:07	chotarak	Maybe the channel should be renamed: #chojure
10:08	chessguy_work	(while still making it sane to parse in clojure
10:08	Chouser	,(reduce (fn [so-far [value & origs]] (conj so-far (* value value))) [] (take-while identity (iterate next [1 2 3 4])))
10:08	clojurebot	[1 4 9 16]
10:08	Chouser	Quiark: that's for you. only study it if you don't want to come up with your own solution. :-)
10:09	kotarak	Chouser, like I wrote above. ;) But your take-while-iterate is more concise, than my tail-seq :)
10:09	chessguy_work	Chousuke, got any recommendations for DSLs to look at that you like?
10:09	Chouser	kotarak: oh, sorry. didn't see that.
10:10	Quiark	Chouser, thanks, looks nice. I was thinking about a loop/recur version, because I'm not yet much used to functional style
10:10	Chouser	but yes, exactly the same approach
10:13	Chousuke	chessguy_work: hmm, not for chess stuff.
10:13	Chousuke	chessguy_work: there are many html/xml relates DSLs around though :P
10:13	chessguy_work	well, if there were a good chess DSL, i wouldn't be making my own :)
10:13	Chousuke	enlive and clj-html for one.
10:14	chessguy_work	i meant another DSL
10:14	Chousuke	perhaps datalog in contrib?
10:20	chessguy_work	Chousuke, thanks, i'll take a look
10:25	opqdonut	is pprint broken in the current contrib?
10:25	opqdonut	user=> (use 'clojure.contrib.pprint)
10:25	opqdonut	java.lang.ClassNotFoundException: clojure.contrib.pprint.PrettyWriter (pprint.clj:0)
10:28	rhickey	what would it take to get a clojure-contrib.jar download that worked with clojure 1.0?
10:28	kotarak	opqdonut: you need to compile contrib: ant -Dclojure.jar=/path/to/clojure.jar
10:29	kotarak	opqdonut: pprint needs some classes generated with gen-class
10:32	cgray	i'm doing (compile 'foo) and it's working, but when i do (import 'foo) it's giving me a NoClassDefFoundError: Could not initialize class foo
10:33	kotarak	cgray: you have to do (require 'foo) or (use 'foo)
10:33	opqdonut	kotarak: yeah thanks, i figured that out too
10:33	kotarak	cgray: import is for classes
10:33	cgray	but foo is a class
10:34	burkelibbey	So PragProg told me Programming Clojure would be shipping within a few weeks... out of curiosity, is there a firmer date floating around?
10:35	gnuvince	June 31st
10:36	burkelibbey	Heh, that's a pretty liberal use of "few weeks". I had gotten my hopes up. Can't wait :)
10:39	danlarkin	rhickey: probably just a post to the ML
10:45	opqdonut	hmm, now it's accumulators that is complaining
10:45	opqdonut	[java] Compiling clojure.contrib.accumulators to /home/jkaasine/src/clojure-contrib-read-only/classes
10:45	opqdonut	[java] java.lang.NoSuchMethodError: clojure.lang.MultiFn.<init>(Lclojure/lang/IFn;Ljava/lang/Object;Lclojure/lang/IRef;)V (accumulators.clj:21)
10:46	opqdonut	i'm using clojure 1.0.0
10:47	opqdonut	same error in complex-numbers if i comment out accumulators from build.xml
10:47	kotarak	opqdonut: try "ant clean" before building and make sure the clojure.jar is used. There is some old compiled code lingering around, which tries to use some old interface.
10:47	opqdonut	ok
10:47	kotarak	opqdonut: maybe also do a rebuild for your clojure.jar
10:47	kotarak	with clean and everything
10:48	opqdonut	yeah, it works
10:58	dnolen_	so has anyone messed around much with c.c.shell-out?
11:01	Chouser	a bit. why?
11:01	dnolen_	Chouser: is there anyway pipe out the output from the shell immediately instead of waiting till the end?
11:02	Chouser	there have been discussions...
11:03	dnolen_	but not much more than that?
11:03	Chouser	in fact I thought there was a patch. hm...
11:06	Chouser	how can the google group search be so poor?
11:06	dnolen_	heh
11:06	dnolen_	I use a special gmail account to load in all my mailing lists. works well.
11:07	dnolen_	i found the email, Perry Trolard submitted a patch.
11:07	Chouser	is that the "articulated" one? that's different
11:07	dnolen_	oh yes, it is.
11:08	Chouser	oh, this was private email, not on the group.
11:08	Chouser	ok, so the main issue is what would be returned?
11:09	dnolen_	system status?
11:09	Chouser	you can get that now. But you want the whole stream, right?
11:10	dnolen_	yes, I want to be able to run commands like git, and see the output at the repl.
11:10	Chouser	it could return the Process, so that you can get stdout and stderr and even stdin from it, etc. But then shell-out's hardly doing anyting for you -- you might as well call .exec yourself.
11:11	dnolen_	i see, perhaps I was confused, what is the intended use case of shell-out over exec?
11:11	Chouser	it is meant to simplify common cases.
11:12	Chouser	and handle the opening and closing of streams, collection of the sub-process (to avoid zombies), etc.
11:13	p_l	kotarak: java's startup speed would work against i, I think..
11:14	dnolen_	so Chouser, so you think I should just use exec directly? I'm OK with that, shell-out just seemed convenient.
11:14	Chouser	I guess I'm not sure what you use-case is yet. One option would be something like:
11:16	dnolen_	I'm building a REPL-side library installer.
11:16	dnolen_	at the REPL:
11:16	dnolen_	(install 'compojure)
11:16	Chouser	(with-sh [[stdin stdou stderr] ("git" "status")] (read print etc stdin))
11:16	dnolen_	then you get feedback about git clone, downloading zip, unpacking zip, ant process.
11:18	Chouser	I guess I'd recommend using .exec directly for now. If you find a clean way to abstract the shelling-out part, perhaps we can use that to improve or replace shell-out
11:18	Chouser	it doesn't currently have any way to get data from the process until it's complete.
11:19	dnolen_	k, good to know. thanks!
11:26	kotarak	Hmm.. the ants don't seem to be sooo antique....
11:29	StartsWithK	dnolen_: http://maven.apache.org/scm/ can help you with calling different tools (you will need them installed on your system), and ant can be used as a lib
11:34	StartsWithK	dnolen_: i tried to do something similar a month ago (http://code.google.com/p/truba/) using ivy and ant to build a clojure lib repository (there are like 40 libs in there) but i guess that will wait for now..
11:35	StartsWithK	biggest problem was, most clojure libs don't have any build system at all, or they require that clojure.jar clojure-contrib.jar are placed in some specific directory, and some event that env variables must be used
11:36	dnolen_	StartsWithK: I'm only slightly familiar with Maven, until someone proves to me that it's easy to use, I'm not going to bother with it. Same with Ivy. And I agree, most clojure libraries don't have or even need a build, it's just source.
11:37	StartsWithK	dnolen_: maven.scm is a separate library, no need for maven build/dependancy tools.
11:37	dnolen_	what I'm working on simply JSON objects hosted on Google Appe Engine that resolve the library. the client side code does everything, it's intended to work with: zip files, git repo, and jars. people can add support for other things if they want, but it's really just to make my own life sane.
11:38	StartsWithK	it gives you something like (checkout :git {:repo bla :rev ble})
11:38	kotarak	I have a fairly stable setup of ant with Ivy (with the latter completely optional). Only some minor adjusts need to be done for a given library. I use it for all my projects.
11:38	StartsWithK	kotarak: you don't need clojure repo for ivy (just use packager resolver with zip on clojure download site)
11:39	StartsWithK	kotarak: something like http://github.com/ksojat/cloak/tree/master (see repo directory)
11:40	kotarak	StartsWithK: I also patched to contrib to provide one jar per module, so that I can say: <dependency ... conf="*->def"/> and only get clojure.contrib.def. 13k jar instead of 2.5Mb jar. :)
11:40	StartsWithK	if projects provided some sore of zip only downloads, repository could me made only as meta index
11:40	StartsWithK	kotarak: i do watch what you do with contib+ivy integration
11:41	StartsWithK	you hit that problem with classes/ directory where everything is mixed
11:41	kotarak	Hmm. cloak looks also interesting.
11:41	StartsWithK	i think cloak will save us :) i'm adding ant task for clojure to it, support for ssh and maven.scm for now
11:42	StartsWithK	we need uniform build system that is no brainer anymore, without it, we can't even start to build repositories
11:43	kotarak	Yeah. Cloak is interesting. I was working on something similar called rabotnik, but that is now on ice it seems. :)
11:44	StartsWithK	hehe, i was planing to extend truba to be full blown build system too, but, as cloak is already there, it may be the best place to place the code
11:46	StartsWithK	dnolen_: will your repo be then just a meta index or you will host download files too?
11:46	dnolen_	StartWithK: just meta index at first, and perhaps host really popular libs.
11:46	dnolen_	http://librynths.appspot.com/install/compojure
11:46	dnolen_	this is just a dummy placeholder for now.
11:46	StartsWithK	something like that i tried with truba too, like only a meta index
11:46	dnolen_	but it's coming along.
11:47	StartsWithK	but as i said, nothing has a build that works
11:47	StartsWithK	so i eneded with creation of repo.zip on google code (40 clojure libs ~6mb)
11:47	dnolen_	StartsWithK: my thought was to have the proper build info in the meta index, that is the index shows how to correctly generate the build
11:47	dnolen_	perhaps we can use a cloak file here.
11:48	dnolen_	until the maintainer fixes their lib.
11:48	StartsWithK	dnolen_: truba does that too, it has a build declarations in its index, but they are ant files
11:49	StartsWithK	yes, thats why i would like to make cloak functional in a short time, so something can be used for building, that would solve meta index problem
11:49	StartsWithK	as http://code.google.com/p/ivyroundup/ is ivy based meta index for different java libs, i think i like how they did it the best, they use svn repo as 'the repo'
11:50	StartsWithK	they don't even have separate download site or anything
11:50	StartsWithK	and that also gives someone a chance to fixate on specific repo revision
11:50	dnolen_	perhaps the meta index supports stable libs.
11:51	dnolen_	anyways you get 1gb on GAE, should enough for the popular libs.
11:51	StartsWithK	as there are something like 70-80 libs for clojure, they are not loarger than 10-15mb combined
11:51	StartsWithK	larger*
11:52	dnolen_	heh yeah.
11:52	AWizzArd	How do I quit a JVM? Something like (System/exit)?
11:53	kotarak	Bingo
11:53	gnuvince	,(System/exit 0)
11:53	clojurebot	java.security.AccessControlException: access denied (java.lang.RuntimePermission exitVM.0)
11:53	kotarak	AWizzArd: are stop all threads.
11:53	kotarak	IIRC
11:53	AWizzArd	thanks
11:54	StartsWithK	kotarak: souldn't you use configs for things like 'build', 'test' 'doc' dependancies, and modules for contrib separation?
11:56	StartsWithK	as i see it now, if i create contribA with my configs, and someone creates contribB, (for libs A an B) lib C can only depend on contrib-all.jar as it can't know what is in contrib A and what is in contribB
11:56	kotarak	StartsWithK: Not sure. I'm not an Ivy wizzard. I tried to do some kind of recursive sub-module built, but without much success. The conf stuff "Just Worked(tm)".
11:56	kotarak	I'm not sure it's the right way. But I also got no feedback on it, so far.
11:57	StartsWithK	here is a feedback :)
11:57	StartsWithK	i only lurk on ml :)
11:57	kotarak	Have to read-up again on configurations.
11:58	StartsWithK	so config is used more like 'i have a lib X that i depend on when i generate docs, not when i distribute a jar'
11:58	StartsWithK	so conf='test' could add <dependency org='junit' ... conf='test'/>
11:58	kotarak	But it seemed to me that they would be used for example for things like default, with-nifty-addition, with-another-optional-thing...
11:59	StartsWithK	well, artifacts are more for that
11:59	StartsWithK	like contrib.jar contrib-src.jar contrib-docs.jar contrib-bla.jar
12:00	kotarak	Ah. I didn't know you could specify artifacts. I see, you did that in cloak.
12:00	StartsWithK	you for now have one module with one artifact, and use configs to generate different profiles of contrib
12:01	StartsWithK	in http://bitbucket.org/ksojat/neman/ (dosn't build anymore now :( )
12:01	StartsWithK	i have something like neman-core -xml -web...
12:02	StartsWithK	they are all separate directories, they get there own classes/ so no mixing of compiled files
12:02	StartsWithK	every dir is a separate module with (for now) one artifact inside
12:03	StartsWithK	they have inner dependancies declared inside there ivy.xml files and toplevel build knows how to compile them in correct order (that is provided with ivy)
12:04	StartsWithK	so maybe a similar split inside contrib, but maybe not on per-file basis, like map-utils seq-utils .. could go in coll-utils module
12:05	StartsWithK	or xml related libs in another..
12:06	kotarak	I grouped eg. types and generic, the whole scattered math stuff...
12:10	StartsWithK	kotarak: will you when finished place a contrib.zip on download page of google code?
12:11	kotarak	I'm not a member of contrib. But I can contact rhickey, if this is a desired goal.
12:15	StartsWithK	just a plain zip with all the jars inside is all that is requiered by ivy, and maybe some sort of version
12:15	kotarak	Wouldn't you have to download the whole zip, just to a single jar?
12:16	StartsWithK	yes, but ivy will cache it for you, and only that one jar is your dependency
12:26	kotarak	StartsWithK: I have to drop out now, but I will look into the issue and will let you know about the progress.
12:26	StartsWithK	kotarak: ok, thanks
12:27	dfdeshom	hi, how do I import a jar file from the cli?
12:28	dfdeshom	s/cli/REPL
12:29	danlarkin	dfdeshom: if it's on your classpath, you do (import '(org.package name))
12:29	Drakeson	walters: ping
12:29	dfdeshom	danlarkin: what if it's not?
12:30	danlarkin	dfdeshom: add it to the classpath and restart your JVM
12:32	dfdeshom	danlarkin: thanks
12:38	dfdeshom	danlarkin: have you used the fact library? I've added it to my classpath but (import fact) gives me an exception
12:39	maacl	Is it bad form to post a link to a Clojure question I have posted to stackoverflow.com?
12:39	danlarkin	dfdeshom: Oh... for using clojure code you use a different function
12:39	danlarkin	sorry, I thought you meant a java jar
12:39	technomancy	dfdeshom: from what I understand fact is deprecated
12:40	stuhood	maacl: i don't think that would be bad form
12:40	technomancy	its author has switched back to test-is
12:42	maacl	Clojure / java.library.path / swank question at stackoverflow.com : http://tinyurl.com/q3257t - can anyone help?
12:42	dfdeshom	danlarkin: oh, ok, i didn't know there was a difference
12:42	dfdeshom	technomancy: what would you suggest using?
12:44	dfdeshom	danlarkin: how do i load a clojure jar?
12:45	technomancy	dfdeshom: test-is is nice
12:46	danlarkin	dfdeshom: http://clojure.org/api#require or http://clojure.org/api#use
12:46	dfdeshom	technomancy: thanks, i see it's in contrib
12:46	dfdeshom	danlarkin: thanks
13:12	cheddar	what does "namespace 'foo.bar' not found after loading '/foo/bar'" mean?
13:13	cheddar	never mind i think i understand...
13:19	cheddar	err actually i don't :-/\
13:20	technomancy	cheddar: do you define a namespace in foo/bar.clj?
13:22	cheddar	technomancy: I have as my first line <ns foo.bar> in a file /foo/bar.clj that is on my classpath
13:23	cheddar	is there something i need to do?
13:24	danlarkin	cheddar: <ns foo.bar> or (ns foo.bar)
13:25	cheddar	"(ns <foo.bar>)" actually
13:25	cheddar	ah.....
13:25	danlarkin	"well there's your problem"
13:51	technomancy	can you get metadata about a namespace?
13:51	technomancy	~^#'clojure.core
13:51	clojurebot	clojure is far closer to perfection then python
13:51	Raynes	than*
13:52	Chouser	,^(the-ns 'clojure.core)
13:52	clojurebot	{:doc "Fundamental library of the Clojure language"}
13:52	technomancy	hmm; but the metadata doesn't include the path to the file that defined it?
13:53	technomancy	I guess the mapping is tenuous since a namespace can be defined anywhere technically
13:53	Chouser	doesn't look like it. Could be multiple files.
13:53	Chouser	I suppose the 'ns' macro could record something -- there's only supposed to be one of those per namespace.
13:53	technomancy	...in theory anyway
13:54	technomancy	I guess I could just assume it's in src/
13:55	Chouser	you could looks for vars in the namespace and see if any of them have files
13:56	Chouser	,(map #(:file ^%) (vals (ns-publics 'clojure.core)))
13:56	clojurebot	("clojure/core.clj" "clojure/core.clj" "clojure/core.clj" "clojure/core.clj" "clojure/core.clj" nil "clojure/core.clj" "clojure/core.clj" "clojure/core.clj" "clojure/core.clj" "clojure/core.clj" "clojure/core.clj" "clojure/core.clj" "clojure/core.clj" "clojure/core.clj" "clojure/core.clj" "clojure/core.clj" "clojure/core.clj" "clojure/core.clj" "clojure/core.clj" "clojure/core.clj" "clojure/core.clj" "clojure/core.clj" "c
13:56	Chouser	there seems to be a consensus
13:59	technomancy	Chouser: very nice.
14:05	Chouser	,(set (map #(:file ^%) (vals (ns-publics 'clojure.core))))
14:05	clojurebot	#{nil "clojure/genclass.clj" "clojure/core_print.clj" "clojure/core_proxy.clj" "clojure/core.clj"}
14:09	lisppaste8	technomancy pasted "slime stacktrace niceties" at http://paste.lisp.org/display/80502
14:10	technomancy	that should allow you to jump to the line referenced by the current line in the stack trace as well as dimming stack trace lines that refer to swank or clojure core stuff
14:10	technomancy	try it out and let me know what you think
14:10	Chouser	sounds nifty. I don't use slime.
14:10	clojurebot	slime is icky
14:11	technomancy	it makes a huge difference to have all those noisy lines dimmed out; makes the relevant stuff much easier to find in a trace.
14:11	technomancy	you should port it to whatever you use. =)
14:20	hiredman	clojurebot: botsnack
14:20	clojurebot	thanks; that was delicious. (nom nom nom)
14:34	twism	technomancy: i'll give it a whirl
14:47	jfields	how do I specify a java enum value?
15:12	Chousuke	hm.
15:12	Chousuke	are they just classes? :/
15:13	Chousuke	try EnumName/ITEM
15:15	Chousuke	Apparently they are just classes. they can even have methods and (non-enum) fields :)
15:21	Chouser	I guess I can't use gen-interface+proxy to make static factory methods, can I. It's gen-class or Java...
15:24	Chousuke	hmm
15:24	Chousuke	enums are actually a fair bit more powerful in java than I even thought.
15:24	Chousuke	you can actually have each enum value have its own implementation of some method :P
15:25	Chousuke	ever* thought too.
15:44	maacl	Clojure Box / java.library.path / swank question at stackoverflow.com : http://tinyurl.com/q3257t - can anyone help?
15:51	sh10151	I keep thinking that laziness somehow reduces a breadth-first-search's memory requirement, but that really doesn't seem right to me. Can anyone convince me that I'm right or wrong?
15:52	Chouser	if you've got a normal one-directional tree, something still has to keep track of parent nodes that you haven't traversed yet.
15:54	sh10151	But could that be a lazy sequence too
15:54	sh10151	?
15:54	Chouser	yes, but a lazy sequence over what?
15:56	Chouser	when the seq-producer has returned the last item of a level, and is asked for the next node, how does it find it?
15:57	Chouser	I think the answer is that it must have internally a list of the parents yet to be traversed, just like an eager breadth-first algo would.
16:03	sh10151	Hmm
16:04	sh10151	I definitely see that
16:04	sh10151	but I am having trouble finding it in my code
16:04	sh10151	assuming everything is lazy
16:05	lisppaste8	sh10151 pasted "where is the space consumption?" at http://paste.lisp.org/display/80508
16:05	sh10151	if children returns a lazy sequence
16:08	sh10151	hmm, I never used branch? -- just copied the tree-seq API
16:09	Chouser	pending accounts for the space consumption
16:09	sh10151	is it not a lazy sequence too?
16:10	Chouser	heh. um.. let's see
16:11	Chouser	slippery, isn't it.
16:11	sh10151	I think it's somehow the thunks in the lazy sequence
16:11	sh10151	I think
16:11	sh10151	but it's driving me crazy
16:11	Chouser	ok, (children node) ... even if children is lazy, the "node" part is known and closed over and stored in the next iteration's 'pending'
16:11	sh10151	'cause I am almost sure you are right
16:18	sh10151	OK, I see it now
16:18	sh10151	have to think about it at the very end, when there are a bunch of nodes
16:18	sh10151	thanks
16:18	sh10151	the leaves will all have this thunk that will return an empty sequence
16:19	sh10151	now to write IDDFS with the same api :-P
16:19	technomancy	Chouser: the thing about getting metadata for a var is that the :file value is still relative to the classpath; I'm curious about where it is on disk
16:20	technomancy	I can just search src/ in the project root, but that doesn't get me stuff that comes from dependencies.
16:20	Chouser	it could be in a .jar or something -- there may not be a regular disk path to it.
16:21	technomancy	right, but I'm working from Emacs; it can open up jars transparently.
16:22	Chousuke	memory usage with lazy seqs is tricky :/
16:23	Chouser	technomancy: seems like you'd want to get the classpath and poke through it yourself. or something.
16:24	Chousuke	to avoid closing over node, could you do (let [therest (children node)] before the lazy-seq?
16:24	technomancy	yeah, I can search myself if there's no existing function for it
16:28	sh10151	Chousuke: I think there's still a thunk for that, and the more nodes you take the children of, the more thunks there are
16:29	sh10151	at the bottom of the tree there will be a lot of empty sequences
16:30	sh10151	but pending contains all the thunks to get them when you reach it, thus making the max memory consumption equal to the number of leaf nodes
16:30	sh10151	which is BFS's memory consumption anyway
16:33	sh10151	it's confusing because infinite sequences are possible
16:33	sh10151	but they only have one thunk at a time
16:33	sh10151	bfs has as many thunks as the deepest level it's visited
16:38	Chouser	I thought 'compile' followed :require directives and compiled those namespaces first if needed.
16:54	twism	hmm..qq...
16:55	twism	how would you create a function that takes an arbitray amout of arguments from a function that tkaes a fixed amount?
16:55	twism	abritary*
16:55	Cark	(reduce + args)
16:56	Cark	(defn [& args] (reduce binary-fn args))
16:57	Chousuke	if the output of your function is acceptable as its input, then reduce is what you want. :)
16:57	twism	sorry didn t frame the question right
16:59	twism	i wonat a function that would take a function with a fixed number of arguments and turn that function into the same function but can take an abritary amount of arguments
16:59	twism	i want*
16:59	Chouser	those extra args would be ignored?
16:59	twism	some of them could be
17:00	Chousuke	the answer depends on what you want the result function to do :p
17:00	Chouser	what would you do with the ones that aren't ignored?
17:01	twism	the gist is that im trying to write a library that a user of this said library can write a function to be used (this function written by the user can take 2 or 3 arguments) but how would i tell how many arguments the function thats being passed by the user takes
17:02	Chousuke	pass it in as a parameter? :p
17:03	Chouser	this sounds familier
17:03	danlarkin	twism: haven't we gone over this already? or am I having deja-vu
17:03	hiredman	the answer is: pass a map
17:04	twism	yes
17:04	twism	we did
17:04	danlarkin	twism: the answer hasn't changed :)
17:05	twism	but the solution we came up with the last time wasnt implemented until now, and did not work out
17:05	twism	pass a map?
17:06	twism	we came up with something like (defn fix-it [f] (do-callback <some magic happens here> new-f))
17:06	twism	:)
17:07	Chouser	where fix-it takes a fn of 2 args and returns a fn of 3 args, where the 3rd is ignroed, right?
17:07	twism	or maybe i stepped away form the computer when this discussion came up
17:07	Cark	what they mean is this : define your callback function with a single parameter, which is a map, and destructure the map in order to get the parameter values
17:07	twism	3rd could be ignored
17:08	twism	ok that would work
17:09	hiredman	Cark: well, I would hardly put words in their mouths, but that is what I mean, for sure
17:12	twism	i dont like it
17:12	twism	but it works
17:12	Cark	hiredman : you're the multiple parameter function of this chan, hence the plpural form
17:13	Cark	how about defining your callback like this : (denf cb ([p1] ...) ([p1 p2] ...)) ?
17:14	hiredman	maps are awesome, what is not to like?
17:14	twism	Cark: i prefer the maps
17:14	Chouser	heck, pass a vector and destructure that.
17:15	twism	i just wanted to provide a user the most straight forward way of defing a function
17:15	twism	the user*
17:16	twism	(defn cb [p1 p2]... or (defn cb [p1 p2 p3]...
17:16	Chouser	Would could provide a replacement for defn that does what you want.
17:17	twism	but (defn cb [[p1 p2 ... pn]] ... could work
17:17	Cark	if you can pass 2 or 3 parameter functions, that means that you need these 2 kind of functions, right ?
17:17	Chouser	but some users want that 3rd arg, and others don't care, right?
17:17	twism	im calling this function with 3 arguments
17:18	hiredman	hmmm
17:18	Cark	ok, then i don't see why you would allow a 4 parameters function to be passed
17:18	Cark	it's trivial for the user to adapt the arity
17:18	twism	if they provide 2 then i get the WrongNumberArguments Exception
17:19	hiredman	jamvm apears to run this 20x slower then the sun jvm
17:19	Cark	this callback function is part of the interface of your api
17:19	twism	yes
17:19	twism	Cark: yes
17:19	hiredman	well, close to 20x
17:19	Chousuke	twism: so you need to require your user's function to accept 3 arguments.
17:19	twism	jamvm.. is iphone java vm right
17:19	twism	?
17:19	Cark	when i call a function in any api, i'm aware of the arity of this function, the same goes for callback
17:20	hiredman	jamvm is a super portable mini jvm
17:20	Chousuke	twism: they don't actually have to DO anything with all three arguments though.
17:20	Chousuke	they can just (defn mycallback [a _ _] ...)
17:20	twism	true i could force them to do that... but its rare for users to implement a function that requires the third argument
17:21	twism	but specification requires i code for the case that this happens
17:21	Chousuke	they can just ignore it in the callback
17:21	twism	its not a big deal
17:22	twism	i can force them to provide a function that takes three arguments
17:22	Chousuke	you could of course wrap the call in a try block and catch the exception, but... that's really ugly.
17:23	twism	it would only be icing on the cake (from where i stand) that they could provide 2 or 3
17:23	twism	CHouske: yeah we went thru that here
17:23	Cark	you could provide two "callback registering" functions
17:24	Cark	(call-me-back-2 cb) and (call-me-back-3 cb)
17:24	Chousuke	IMO that's worse than just being forced to accept three arguments :P
17:24	Cark	hehe yes
17:24	twism	Cark: i agree with Chouske
17:25	twism	im going to go with the (defn cb [a b _]... approach
17:25	hiredman	bah
17:26	hiredman	clojurebot: maps?
17:26	clojurebot	maps are functions
17:26	hiredman	clojurebot: maps is also <reply>maps are AWESOME
17:26	twism	i had javm running on my iphone
17:26	clojurebot	c'est bon!
17:26	twism	jamvm*
17:26	twism	was doing some cool rhino iphone stuff with it
17:27	twism	i need to see how clojure fares on my iphone
17:28	hiredman	I have three implementations of this function (searchs a byte array to see if it contains a given byte) they all run much slower on jamvm
17:29	hiredman	the fastest function on the sun jvm is thirdplace on the jamvm
17:29	hiredman	er
17:29	hiredman	second place
17:29	hiredman	third place is the same
17:39	Chouser	twism: that's jailbroken?
17:42	hiredman	Steve Jobs has been quoted as saying "Java's not worth building in. Nobody uses Java anymore. It's this big heavyweight ball and chain."
17:42	hiredman	Zing!
17:47	dnolen	hiredman: until I used Clojure, I would have agreed with him ;)
17:55	cads	you guys think anyone will ever make a bare metal clojure machine?
17:55	dnolen	like a Lisp machine?
17:55	cads	heh, no, a virtual machine
17:56	hiredman	I have been reading through http://www.loper-os.org/
17:56	cads	rather, a compiler/interpreter
17:56	hiredman	the loper-os guy seems to want to build a modern lisp machine
17:57	cads	i remember reading a tweet about "when clojure's compiler is written in clojure"... and it occurred to me that at that point we could change the target language away from jvm
17:58	cads	hiredman: I was sad to hear that lisp machines existed and the disappeared
17:58	cads	then*
17:58	hiredman	well, I think clojure will always be strongly tired to the jvm
17:58	cads	to me it doesn't lose much of its charm even separated from java interop
17:59	hiredman	clojurebot: clojure?
17:59	clojurebot	"[Clojure ...] feels like a general-purpose language beamed back from the near future."
18:00	cads	:)
18:01	cads	except for #(f %1 %2), that feels like a mix between a lambda and some shell-script
18:01	dnolen	One Clojure can compile itself, I am sure people will want to port to other runtimes beyond the JVM. Clojure is an idea, and the JVM is a good place to grow it.
18:02	cads	dnolen: I think so too, and that will be a very neat process to witness
18:02	hiredman	clojurebot: clojure?
18:02	clojurebot	clojure is like life: you make trade-offs
18:03	cads	clojurebot: paste?
18:03	clojurebot	lisppaste8, url
18:03	lisppaste8	To use the lisppaste bot, visit http://paste.lisp.org/new/clojure and enter your paste.
18:09	hiredman	clojurebot: clojure?
18:09	clojurebot	clojure is far closer to perfection then python
18:09	technomancy	hiredman: did you see this? http://twitter.com/gvanrossum/status/1838308947
18:14	lisppaste8	cads pasted "pseudo-module" at http://paste.lisp.org/display/80515
18:15	cads	here I've tried to create a function which, given a "less-than" type comparison function, will instantiate custom versions of the rest of the comparison functions
18:16	hiredman	technomancy: yeah :P
18:17	hiredman	cads: it has to do with how def (which the macro defn uses) works
18:17	lisppaste8	cads annotated #80515 "correction" at http://paste.lisp.org/display/80515#1
18:18	hiredman	the namespace def operates in is set at compile time
18:19	cads	hiredman: I was thinking that a macro could not only insure that the definitions end up in the right namespace, but also let you rename the functions to reflect your customization
18:19	hiredman	cads: I woud use intern
18:20	hiredman	(doc intern)
18:20	clojurebot	"([ns name] [ns name val]); Finds or creates a var named by the symbol name in the namespace ns (which can be a symbol or a namespace), setting its root binding to val if supplied. The namespace must exist. The var will adopt any metadata from the name symbol. Returns the var."
18:20	hiredman	(intern ns my> (fn [x] something here))
18:22	cads	that'll work even if that line of code is in another namespace, right?
18:23	hiredman	actually, I think if you use intern it doesn't even need to be a macro
18:23	hiredman	cads: I think so
18:23	cads	i'm trying my example again
18:29	mrsolo	i can't do (.PI Math) can i?
18:30	hiredman	,(Math/PI)
18:30	clojurebot	3.141592653589793
18:30	cads	you can do (. Math PI)
18:30	hiredman	,(. Math PI)
18:30	clojurebot	3.141592653589793
18:30	hiredman	PI is not a method
18:31	mrsolo	that i know i just like (.xxx yy) form better.. oh well
18:33	hiredman	you could write a macro
18:33	hiredman	that does a transform on the input, but it would be tricky, due to .xxx being valid syntax in many cases
18:33	mrsolo	i can eventualy :-) my clojure fu isn't there yet
18:44	Chousuke	,Math/PI
18:44	clojurebot	3.141592653589793
18:44	Chousuke	right, that form works too
18:45	Chousuke	interesting that the function call form does as well.
18:48	lisppaste8	cads annotated #80515 "Revision" at http://paste.lisp.org/display/80515#2
18:48	cads	hiredman, check that out, that works pretty well!
18:48	cads	thanks for the help :)
18:52	Chousuke	Looks like that should be a macro :/
18:54	cads	probably :)
18:55	cads	do you think that pattern is acceptable for use?
18:55	Chousuke	well, if you end up generating many global names, you should perhaps rethink your design
18:56	Chousuke	but it's not really wrong
18:58	Chousuke	though using a runtime mechanism like that looks dubious. you'd never call equalifier programmatically during runtime (it'd be really weird if you did), so it's better to just make a macro.
19:00	cads	well it is a higher order function, I could see it being useful at runtime, but not really in the current side-effecting state. If equalifier returned maps storing fns it could be part of some kind of logic engine
19:00	Chousuke	yeah, that way it's just fine
19:00	Chousuke	even good functional design
19:01	Chousuke	but that side-effecting thingamabob isn't a function at all; it's a procedure.
19:02	cads	Since the side effect form is for humans to have it easier, I think there's nothing wrong with making it a macro like you say. Maybe a macro would let you have better control of the target namespace, or allow you to specify the modular structure in a less verbose way
19:02	Chousuke	well, actually making it a macro only has the difference is that a macro can be expected to make new global stuff appear, because it's generating code.
19:03	Chousuke	of course, you should document it if it does have global effects :)
19:05	cads	can I write a map that contains fns that are defined in terms of symbols that are not yet bound?
19:05	Chousuke	the difference is that macro calls are always written directly in the source. you can't pass around a macro and call it at runtime to generate stuff. (disclaimer: without hideous trickery and eval)
19:05	Chousuke	sure; declare the symbols first.
19:05	cads	yeah, but the idea of passing around equalifier and calling it here and there randomly in its current form is silly :D
19:08	Chousuke	if you made equalifier a function that returns a map of names to (anonymous) functions, you could very well use it to generate new functions at runtime; it wouldn't even be ugly at all. The functions are just values in a map, so it's no different from any other map returning function :)
19:09	cads	I want to represent a parametric module as a map of dependent functions defined in terms of the module's parameter symbols.. wait, hey, that's pretty much what you say
19:10	dnolen	cads very interesting, this got me thinking.
19:10	dnolen	what I never like about putting fns in maps is that they can't change if you redefine them
19:10	dnolen	putting vars in a map works
19:10	dnolen	because vars implement IFn
19:11	lisppaste8	dnolen pasted "vars in maps" at http://paste.lisp.org/display/80518
19:13	dnolen	not sure if that's helpful to you at really, but it's something to think about...
19:14	Chousuke	doesn't need to be vars unless you have to redefine them later without touching the map. (which gets uglyish again)
19:14	lisppaste8	Chousuke annotated #80515 "untitled" at http://paste.lisp.org/display/80515#3
19:14	Chousuke	I make no guarantee of the parens, but you should see the general idea there :)
19:16	Chousuke	I also forgot to remove the docstring...
19:16	cads	well, for mine I'd need something like frozen unevaluated fns (def depent-fs {fname (*fn [a b] f-depend) & }), where the fn objects would have unbound symbols, and then another function that would act like (let [f-depend my-f] dependent-fs), where the unbound symbols would be bound and the functions evaluated to create actual ifns
19:18	Chousuke	hm
19:18	cads	of course I could represent it like this: (fn [f-depend] {f-name (fn [a b] (f-depend a b))})
19:18	Chousuke	that seems good.
19:18	cads	then, I could compose modules using functions that works with these special lambdas
19:19	Chousuke	looks monadic
19:19	cads	and have a final macro that interns a module with user specified dependency functions
19:19	cads	god knows everything's a monad :D
19:19	Chousuke	:)
19:20	Chousuke	do those functions always have just one function they depend on?
19:21	Chousuke	you could make some macro sugar that allows you to use the f-depend name without explicitly writing the lambda
19:21	cads	a vector space might need 4-6 functions
19:21	cads	and your modules may always need any number of constants
19:21	Chousuke	okay. scratch that then.
19:22	cads	but even in the case of functions, you might want the option of defaults :P
19:22	Chousuke	your "f-depend" shouldn't necessarily have to be a function.
19:22	Chousuke	it could just be a map of whatever the function depends on.
19:22	cads	ahah
19:23	Chousuke	and then you call ((dependent-f map-of-dependencies) args moreargs)
19:23	cads	and I could merge the user provided dependencies with a corresponding defaults map
19:23	Chousuke	yeah.
19:24	cads	this could be very useful to me
19:24	Chousuke	the dependent-f will only need to document what keys it uses to look up its dependencies
19:24	cads	yeah, and with a macro it could actually look very natural
19:28	Chousuke	you could use a macro to bind the depends you need automatically (define-dependent-function foo [regular-arglist] [depend1 :depend-key, depend2 "another depend key"] (do-stuff-with (depend2 regular-arglist) depend1))
19:33	Chousuke	in fact the depend list could be a clojure map destructuring form and then you could use it in let as is :P
20:01	cads	(defn mod-intern [prefix mod & depends] let [insta-mod (apply mod depends)] (do-seq [[name fun] insta-mod] (intern ns (symbol (str prefix name)) fun)))) , where a module is a function that takes values and returns a map of name/value pairs
20:04	cads	the equalifier example becomes (def equalifier (fn [<fn]
20:04	cads	{ "<" #(<fn %1 %2) ">" #(<fn %2 %1) "=" #(not (or (<fn %1 %2) (<fn %2 %1))) "<=" #(not (<fn %2 %1)) ">=" #(not (<fn %1 %2))}))
20:07	cads	and usage is like this : (mod-intern "l_0-comp" equalifier (fn [a b] (< (apply max a) (apply max b)))), (l_0-comp= [1 23 123 5232 123 9999] [1 -13 9999 100 2003]) => true
20:08	cads	hehe, I really need to learn how to write macros
20:16	Chousuke	yeah, you definitely don't want to use intern :P
20:17	Chousuke	also, keywords as map keys instead of strings would be more idiomatic for a map like that, I'd say.
20:19	Chousuke	and it still looks like generating global names at all (even with macros) is not the solution
20:20	Chousuke	or well, it depends :P
20:21	Chousuke	but your mod-intern is generating names like equalifier did too, so it's got the same problem.
20:22	Chousuke	though if the intent is to generate a programming API from a map of dependencies and other stuff, then it's fine I guess.
20:23	Chousuke	I'm just wondering where you'd use something like that.
20:24	cads	well you could create a html module that takes a string module as a parameter, and then lets you parse strings of that type
20:25	Chousuke	strings of what type?
20:25	Chousuke	html type? :/
20:28	cads	no, say you have a string module that lets you define ascii strings over sequences of an arbitrary datatype, and you've defined the ascii strings over sequences of braille charachters. Well now you get all the string processing functions you can do on ascii, only the modifications work to produce the braille equivalent. And, with your spiffy html module, you can now parse html represented as braille :P
20:28	cads	hahaha, forgive me if the example is less than motivating, that's all pretty goofy :)
20:29	Chousuke	so hm, you could just map a braille->string function over your braille seq. :/
20:30	hiredman	~functions
20:30	clojurebot	functions are maps
20:30	Chousuke	I guess I get the basic gist of it.
20:31	Chousuke	you want to parametrise a set of operations on some function that can have different output based on what the function is.
20:32	Chousuke	and then perhaps define a module that depends on such a set of operations
20:32	cads	I think the concept of namespace should be doing this for us
20:33	cads	but I'm not sure
20:33	Chousuke	well, it could.
20:33	Chousuke	you could define the set of operations differently in different namespaces
20:34	Chousuke	and import them with an :as directive in the "user" namespace
20:34	cads	importing could involve passing the imported namespace some parameters and it instantiating some of its features
20:34	Chousuke	instantiating how?
20:35	cads	well it messes up with compiled code
20:35	Chousuke	true; you wouldn't be able to use multiple modules simultaneously
20:36	Chousuke	but that problem will remain if you generate names, too
20:36	Chousuke	or it'll just be transformed :P
20:36	cads	hm
20:37	cads	I think the idea would be parametric namespaces, where different parts of the program can refer to different configurations of the same namespace
20:38	cads	each different configuration relying on different values of the namespace's set of parameters
20:39	Chousuke	you could do it this way: model your module as a function; then from the user namespace, pass a configuration map to the module function, and hold onto whatever it returns; the returned thing would be some data structure containing anonymous functions and data that can be accessed with some functions operating on the data structure (ie, not global, generated names)
20:39	Chousuke	then you could have as many modules and configuration combinations as you want.
20:39	cads	and do all sorts of crazy stuff
20:39	hiredman	Chousuke: function could just return a namespace
20:40	Chousuke	hiredman: indeed it could!
20:40	cads	could a function return a namespace?
20:40	Chousuke	though, is that referentially transparent :P
20:40	cads	or would it just define the namespace?
20:40	hiredman	of course
20:40	hiredman	Chousuke: nope
20:40	Chousuke	,(create-ns 'foo)
20:40	clojurebot	#<Namespace foo>
20:40	Chousuke	there :P
20:40	hiredman	actually
20:41	Chousuke	,(in-ns 'foo)
20:41	clojurebot	#<Namespace foo>
20:41	hiredman	hmmm
20:41	Chousuke	the problem now is, that the namespace definition is global
20:41	Chousuke	and you want to avoid that.
20:41	hiredman	does he?
20:41	cads	in part yes and in part no
20:41	cads	I think modelling a module as a function is great, because that's what it is
20:41	Chousuke	also how do you get a value from a namespace?
20:42	cads	i can compose those functions in a monad and operate on them in other ways
20:42	hiredman	,(find-var 'clojure.core 'map)
20:42	clojurebot	java.lang.IllegalArgumentException: Wrong number of args passed to: core$find-var
20:42	hiredman	bah
20:42	cads	but then I want to realize what I've created into a namespace, so that I can program with the generated module
20:42	Chousuke	cads: the equalifier thingy returning a map of keywords to functions is a simple example of what I described.
20:43	Chousuke	cads: equalifier is the module and the function is the parameter
20:43	cads	Chousuke: yup :)
20:43	cads	and the realization part is a simple enough macro to write
20:43	cp2	,(doc find-var)
20:43	clojurebot	"([sym]); Returns the global var named by the namespace-qualified symbol, or nil if no var with that name."
20:44	cp2	,(find-var 'clojure.core/map)
20:44	clojurebot	#'clojure.core/map
20:44	cp2	e
20:44	cp2	r
20:45	cads	Chousuke: I think it would be pretty easy to create a fairly clean module system this way
20:45	Chousuke	hmm
20:45	hiredman	,(find-var (ns-resolve (create-ns 'clojure.core) 'map))
20:45	clojurebot	java.lang.ClassCastException: clojure.lang.Var cannot be cast to clojure.lang.Symbol
20:45	hiredman	bah
20:46	Chousuke	,(#'eval `(~(symbol "def") ~'foo 1))
20:46	clojurebot	DENIED
20:46	Chousuke	damn!
20:46	Chousuke	oh, right, it gets expanded into (var eval) so it's picked up ;(
20:47	Chousuke	,((find-var 'clojure.core/eval) `(~(symbol "def") ~'foo 1))
20:47	clojurebot	#'sandbox/foo
20:47	Chousuke	,foo
20:47	clojurebot	1
20:47	Chousuke	\o/
20:48	hiredman	,(intern ns foo 1)
20:48	clojurebot	java.lang.ClassCastException: java.lang.Integer cannot be cast to clojure.lang.Symbol
20:48	cads	I know that I could use it in many different places, for example in my vector space library, I'd like to create vector spaces parameterized over different linear data structures, such as strings of words, or polynomial equations. The exciting thing about this approach is that I can automate not only the constructions of the secondary vector space functions like vector magnitude or projection
20:48	hiredman	,(intern ns 'foo 1)
20:48	clojurebot	#'sandbox/foo
20:48	hiredman	but don't spread it around
20:48	Chousuke	oh right, that works too...
20:49	cads	I can also automatically generate test code that will test to see if the basis functions I've defined for my vector space are consistent with the definitions of a vector space
20:49	Chousuke	oh well, you can still only define things.
20:49	Chousuke	the rest of the sandbox is still functional
20:50	hiredman	you could use the exception thing to DoS
20:50	Chousuke	clojure is too dynamic ;(
20:51	Chousuke	the JVM security model is not enough for it.
20:53	Chousuke	though I wonder if anythign is.
21:14	Drakeson	how do you (list \a \b) -> "ab" ?
21:14	hiredman	,(apply str '(\a \b))
21:14	clojurebot	"ab"
21:15	Drakeson	thanks.
21:15	Drakeson	why can't we do (into "" ...) ?
21:16	hiredman	strings are not Collections
21:16	hiredman	the seq function just happens to know how to turn them into sequences
21:17	hiredman	and first, rest, etc call seq on their argument first
21:17	Drakeson	I see, thanks.
21:18	hiredman	although, I wouldn't mind into being inhanced to do that
21:20	Drakeson	yeah, that would be useful
21:24	mrsolo	why does this work? (:2 {:2 3})
21:24	hiredman	keywords are IFns
21:24	hiredman	they look themselves up in a map
21:24	hiredman	(:i {:i 2})
21:24	hiredman	,(:i {:i 2})
21:24	clojurebot	2
21:25	hiredman	,(:i {:j 2} 3)
21:25	clojurebot	3
21:25	Chousuke	a map also is a functions of its keys
21:25	Chousuke	-s
21:25	hiredman	,(ifn? {})
21:25	clojurebot	true
21:25	hiredman	,(ifn? :foo)
21:25	clojurebot	true
21:27	mrsolo	ifns?
21:27	Chousuke	,(map ifn? [[], #{}, {}, 'symbol, :keyword]) ; anything else
21:27	clojurebot	(true true true true true)
21:27	cp2	think you got it all
21:27	cp2	er
21:27	cp2	struct maps
21:28	Chouser	,(map ifn? [[], #{}, {}, 'symbol, :keyword, #(), (fn [])])
21:28	Chousuke	those are maps
21:28	Chouser	you forgot functions
21:28	Chouser	:-)
21:28	cp2	yeah i figured
21:28	Chousuke	mrsolo: IFn is hte interface that an object must implement to be usable in operator position
21:28	Chousuke	Chouser: omitted those as obvious; guess it isn't.
21:28	Chouser	naw, you're probably right.
21:29	mrsolo	ah ha.. jedi mind trick... thanks :-)
21:29	mrsolo	handy :-)
21:29	Chousuke	mrsolo: the only exceptions are special forms and macros (user-defined special forms!)
21:32	mrsolo	okay
21:32	Chousuke	,(ifn? ->) ; macros are a bit weird anyway
21:32	clojurebot	java.lang.Exception: Can't take value of a macro: #'clojure.core/->
21:32	hiredman	,(ifn? #'->)
21:32	clojurebot	true
21:32	Chouser	oh, vars.
21:33	Chousuke	hiredman: that's a var, not a macro, though.
21:33	Chouser	,(ifn? #'proxy)
21:33	clojurebot	true
21:34	hiredman	,(#'-> x foo)
21:34	clojurebot	java.lang.Exception: Unable to resolve symbol: x in this context
21:34	hiredman	,(#'-> 'x 'foo)
21:34	clojurebot	(foo x)
21:34	Chousuke	the #'foo syntax gives you a nice way to cheat with macros like that.
21:34	hiredman	,(#'-> 'x 'foo 'baz 'bleep)
21:34	clojurebot	(clojure.core/-> (clojure.core/-> x foo) baz bleep)
21:34	hiredman	hmm
21:34	Chousuke	it runs the macro function as usual but doesn't eval the result
21:35	Chousuke	hm, nice sunrise
21:36	Chousuke	insomnia has its benefits sometimes ;(
21:36	hiredman	,(binding [-> (vary-meta #'-> assoc :macro false)] (-> 'a 'b 'c 'd))
21:36	clojurebot	java.lang.ClassCastException: clojure.lang.Var cannot be cast to clojure.lang.IObj
21:37	Chousuke	~source defmacro
21:37	Chouser	wouldn't work anyway, I think. The compiler would expand -> before the binding was set
21:38	hiredman	I rebind doc in clojurebot somehow
21:39	Chousuke	,foo
21:39	clojurebot	1
21:40	Chouser	,(alter-meta! #'-> dissoc :macro)
21:40	clojurebot	{:ns #<Namespace clojure.core>, :name ->, :file "clojure/core.clj", :line 1017, :arglists ([x form] [x form & more]), :doc "Threads the expr through the forms. Inserts x as the\n second item in the first form, making a list of it if it is not a\n list already. If there are more forms, inserts the first form as the\n second item in second form, etc."}
21:40	Chouser	,(-> 'a 'b)
21:40	clojurebot	(b a)
21:40	Chouser	,(alter-meta! #'-> assoc :macro true)
21:40	clojurebot	{:macro true, :ns #<Namespace clojure.core>, :name ->, :file "clojure/core.clj", :line 1017, :arglists ([x form] [x form & more]), :doc "Threads the expr through the forms. Inserts x as the\n second item in the first form, making a list of it if it is not a\n list already. If there are more forms, inserts the first form as the\n second item in second form, etc."}
21:40	Chouser	,(-> 'a 'b)
21:40	clojurebot	(quote a)
21:41	Chousuke	,(.setMacro #'->); should work too I guess
21:41	clojurebot	nil
21:42	Chousuke	,(intern-ns 'my+ +)
21:42	clojurebot	java.lang.Exception: Unable to resolve symbol: intern-ns in this context
21:42	Chousuke	hm
21:43	Chousuke	oh well, time to go
21:43	Chousuke	later
21:43	Chouser	,(ns-intern 'my+ +)
21:43	clojurebot	java.lang.Exception: Unable to resolve symbol: ns-intern in this context
21:45	Chouser	,ns
21:45	clojurebot	#<Namespace sandbox>
21:45	Chouser	,(intern 'sandbox 'my+ +)
21:45	clojurebot	#'sandbox/my+
21:45	Chouser	,(my+ 5 10)
21:45	clojurebot	15
21:50	eee	hi
21:50	eee	reduce is my hammer right now, but I'm not sure it is right
21:50	eee	i need to loop through a set
21:51	eee	and update several data structures at the same time
21:51	eee	conditionally
21:51	eee	that's cake in python. totally confusing to me in clojure
21:51	eee	anyone got advice?
21:51	eee	thanks
21:52	hiredman	sure, reduce is for that
21:52	eee	one unsatisfying way would be with three reduce commands that each have the same logic
21:52	Chouser	if you're doing more than one thing per iteration, you might find loop/recure less confusing.
21:52	Chouser	is there any reason not to iterate multiple times?
21:52	eee	the check is the same
21:53	eee	for each item that p is true
21:53	eee	do these three things
21:53	Chouser	put the check in a fn?
21:53	eee	why go through list and retest three times?
21:53	Chouser	hm. sure.
21:53	eee	loop recur hmmm
21:53	eee	that could work
21:54	eee	can loop recur's be nested?
21:54	hiredman	,(reduce #(if (zero? (mod %2 2)) (update-in % [:evens] inc) (update-in % [:odds] inc))) {:evens 0 :odds 0} (range 20))
21:54	clojurebot	java.lang.IllegalArgumentException: Wrong number of args passed to: core$reduce
21:54	hiredman	bah
21:54	dnolen	(defn yr-fn [thing] (if (p? thing) (-> thing (step1) (step2) (step3)) thing)
21:54	dnolen	(map yr-fn yr-set)
21:55	eee	i'm trying to understand
21:56	eee	i've been avoiding that arrow
21:56	dnolen	,(-> 4 (+ 1) (* 2))
21:56	clojurebot	10
21:56	dnolen	it's not that scary ;)
21:56	eee	it is
21:57	eee	i'm trying to figure out how to apply that to my problem
21:57	eee	i'll write it in pseudocode
21:57	hiredman	,(reduce #(update-in % [(if (zero? (mod %2 2)) :evens :odds)] inc) {:evens 0 :odds 0} (range 1 20))
21:57	clojurebot	{:evens 9, :odds 10}
21:57	dnolen	might not apply, the other solutions might be better. just my interpretation.
21:58	eee	those wierd faces make it hard to read :(
21:59	eee	i can cutn paste to an editor
21:59	eee	ahh now I can see it
21:59	hiredman	you might want to get a real irc client
22:00	eee	never found a free one for mac
22:00	hiredman	~google free mac irc client
22:00	clojurebot	First, out of 219000 results is:
22:00	clojurebot	Macintosh Chat Clients
22:00	clojurebot	http://www.irchelp.org/irchelp/mac/
22:01	hiredman	I would just install irssi
22:01	eee	dnolen are those step 1 step 2 step 3 things each reduces?
22:01	dnolen	no they are just whatever update steps you want
22:02	eee	i think the other solution is what i have to do
22:02	eee	but maybe I don't get it
22:02	eee	i need to say
22:03	eee	if current distance plus length less than previous length:
22:03	eee	change value in heap
22:03	eee	and
22:03	eee	update "distances"
22:03	eee	and
22:04	eee	change path to go from current node to new node
22:04	eee	and do that for each node
22:04	eee	in a set
22:04	eee	so three data structures need to be mutated, really
22:04	eee	easiest way would be to use atoms or something
22:05	hiredman	nah
22:05	eee	but what hiredman wrote looks possible
22:05	hiredman	or you can use loop/recur
22:05	eee	i don't get the syntax yet
22:06	eee	why that if is in square brackets
22:06	hiredman	oh
22:06	hiredman	that is just for update-in
22:06	hiredman	(update-in {:foo 1} [:foo] inc)
22:06	hiredman	,(update-in {:foo 1} [:foo] inc)
22:06	clojurebot	{:foo 2}
22:06	hiredman	,(update-in {:foo {:bar 1}} [:foo :bar] inc)
22:06	clojurebot	{:foo {:bar 2}}
22:07	eee	ok
22:09	eee	,(reduce #(conj %1 %2) #{} {:evens 0 :odds 0} (range 1 20))
22:09	hiredman	that won't work
22:09	hiredman	reduce takes 2 or 3 args
22:09	eee	,(reduce #(conj %1 %2) #{} {:evens 0 :odds 0} (range 1 20))
22:09	clojurebot	java.lang.IllegalArgumentException: Wrong number of args passed to: core$reduce
22:10	hiredman	not 4
22:10	eee	so loop recur can be nested in loop recur?
22:10	eee	i may try that
22:11	hiredman	yeah
22:11	eee	thanks
22:12	eee	then when I am done with the loop recur because I am out of elements, return a list of the three structures
22:12	eee	then destrcuture
22:12	eee	insane
22:15	eee	oh, now I understand dnolen
22:15	eee	the function does one element for each structure
22:15	eee	then I map it to the "foreach"
22:16	eee	but can I do it without the arrow ....
22:18	dnolen	eee: loop/recur sounds like a better fit for what you are trying to accomplish.
22:18	dnolen	the arrow isn't magical, just a macro that converts the expression to normal form.
22:18	eee	then return the three structures in a list? then destructure?
22:18	eee	i can't switch back to normal form while learn all these parenthesis
22:18	dnolen	(-> 4 (+ 1) (* 2)) becomes (* (+ 1 4) 2)
22:19	dnolen	oops
22:19	eee	yeah, let's stick to the second
22:19	dnolen	(-> 4 (+ 1) (* 2)) becomes (* (+ 4 1) 2)
22:19	dnolen	i mean
22:19	eee	second is much clearer to me
22:20	eee	anyway, so i need to return a list to get my three structures, right? ... from the loop-recure
22:20	eee	-e
22:21	dnolen	yes that's one way to do it, or return a map, whatever feel most natural.
22:21	eee	oh, I see
22:22	eee	this function is looking insane right now
22:22	eee	40 lines long
22:22	eee	and probably 50 more to go
22:22	eee	thanks for the help
22:23	eee	i'll try that. it's kinda cool to feel like I'm starting over learning how to program
22:24	hiredman	sounds like it's time to break the function up
22:39	danlarkin	yeah definitely
22:41	eee	,(let [[a b & c] (range 3 9)])
22:41	clojurebot	nil
22:41	eee	,(let [[a b & c] (range 3 9)] a)
22:41	clojurebot	3
23:23	danlarkin	not a big deal, but maybe this error message should be the same:
23:24	danlarkin	,(hash-map 1 2 3)
23:24	clojurebot	java.lang.IllegalArgumentException: No value supplied for key: 3
23:24	danlarkin	,(array-map 1 2 3)
23:24	clojurebot	3
23:24	danlarkin	umm weird
23:26	hiredman	array-maps are fast and loose
23:26	danlarkin	locally I get an error
23:27	danlarkin	java.lang.ArrayIndexOutOfBoundsException
23:27	hiredman	it is undefined bahaviour
23:37	danlarkin	,(nth {1 2 3 4} 1)
23:37	clojurebot	java.lang.UnsupportedOperationException: nth not supported on this type: PersistentArrayMap
23:37	danlarkin	,(first {1 2 3 4})
23:37	clojurebot	[1 2]
23:38	danlarkin	why is this
23:39	hiredman	nth operates on seqs
23:39	hiredman	first calls seq on its arg
23:39	danlarkin	is it because it'd be suboptimal to call seq on nth's argument in every case?
23:40	danlarkin	why doesn't nth call seq just like first calls seq
23:41	hiredman	well, maps are not ordered, so taking the 3rd thing doesn't make sensesnse
23:41	hiredman	but, yeah, first works
23:42	danlarkin	array-maps are ordered
23:42	danlarkin	plus if taking the 3rd thing doesn't make sense then taking the first thing doesn't make sense :)
23:42	danlarkin	plus fnext will work, etc