#clojure – 2009-10-30

2009-10-30

00:00	gerry_	ok,not use println
00:02	gerry_	not use println is 35 vs 44
00:02	Knekk	see?
00:03	gerry_	about 20% boost
00:03	gerry_	i thought it should be > 40% :)
00:04	Knekk	increase to 500k iterations? Does your ratio hold?
00:05	gerry_	let's try
00:06	gerry_	206 vs 256
00:06	gerry_	still about 20%
00:06	Knekk	ok
00:07	Knekk	dunno. you should ask someone who knows the internals about your missing improvement
00:07	gerry_	AwizzWard?
00:15	gerry_	chouser's patch still not used yet?
00:20	Raynes	Apparently, the bleeding edge VimClojure works fine for me. It's a little inconvenient to have to have any file you edit on the classpath, but I'll manage.
00:20	nroot	Hi I am new to clojure, but I have some experience in Erlang and Map reduce. The reason I am learning clojure is because it is said that it is build for concurrency from ground up.
00:20	nroot	My question is what is it parallelism model, is it thread based ? Meaning it will only work on machine with large number of cores or is it map reduce like meaning it can work on large number of machines with each having 1 or 2 cores.
00:20	tomoj	oh, damn
00:21	tomoj	the error I was having with c.c.http.agent was because I changed something in there to intentionally cause an error so I could see the backtrace, and forgot to change it back
00:21	gerry_	oh,that's 217 vs 304
00:22	gerry_	about 40% great
00:22	tomoj	nroot: clojure's concurrency model is based on threads
00:22	tomoj	it doesn't do anything at all to help you with distributed computing
00:23	nroot	tomoj: so it can not exploit working on something like google app engine
00:23	tomoj	in fact rhickey thinks it's outright impossible to do what clojure does for distributed computing
00:23	tomoj	I dunno anything about google app engine
00:24	gerry_	minibenchmark result: deftype about 40% faster than defstuct
00:24	tomoj	if you have a multi-threaded application clojure will help you deal with the problems that usually arise with multi-threaded applications and state
00:24	nroot	tomoj: thanks
00:24	technomancy	tomoj: "outright impossible" is strong wording... he's just said that it doesn't belong in the core language
00:25	tomoj	no, he said it's "doomed"
00:25	tomoj	I'm not talking about distributed help in general, just that he said trying to do what clojure does for multi-threaded state in a distributed way is doomed
00:25	tomoj	certainly we can build some clojure tools that help with distributed computing
00:26	technomancy	oh sure, but that's kind of tautological.
00:26	technomancy	"providing tools to help with shared mutable state is impossible when there's no shared state."
00:27	tomoj	heh, yeah
00:27	tomoj	but I'm sure he didn't mean a tautology when he said it
00:27	tomoj	I just am too noob to say it right
00:27	tomoj	the statements I'm talking about are in http://www.infoq.com/presentations/Value-Identity-State-Rich-Hickey
00:27	technomancy	hehe
00:27	chouser	nroot: There are several projects that are working to help make it easy to distribute Java work across multiple machines
00:28	nroot	chouser: like ?
00:28	chouser	Clojure can take advantage of some of these already, and will do more in the long run
00:28	chouser	The one that comes to mind is Hadoop, but there are others.
00:29	chouser	I think there's also one that may be pure Clojure. http://github.com/amitrathore/swarmiji
00:30	leif-p	I believe one company is already using clojure with Hadoop + Cascading for their data processing.
00:31	chouser	But Clojure itself is more concentrated on the multicore/multithreaded model where you can read memory more cheaply than passing messages to another process, and don't have to worry about the same failure cases as distributed systems.
00:31	wooby	nroot: clojure runs fine on app engine
00:32	wooby	nroot: although the STM is busted because of the way google deploys stuff
00:33	tomoj	my neural networks where each node has a seq of references to other nodes: buggy
00:33	wooby	nroot: http://elhumidor.blogspot.com/2009/04/clojure-on-google-appengine.html
00:33	tomoj	my neural networks where each network is a single immutable value: not buggy
00:33	tomoj	:D
00:33	wooby	tomoj: what kind of network?
00:34	tomoj	like, sum the inputs and run them through a sigmoid
00:34	technomancy	terracotta, JMS, AMQP
00:34	technomancy	AMQP is language-agnostic
00:34	technomancy	but works great with Clojure
00:34	technomancy	yeah, that wraps AMQP actually
00:34	technomancy	anyone want to test out my swank-clojure 1.0 release candidate?
00:34	technomancy	should be an even easier install than M-x clojure-install
00:34	technomancy	google disallows new threads, so STM is not that interesting without that
00:34	wooby	i was working on something like that the other day, from turing omnibus
00:36	tomoj	mine are fully lazy (i.e. cache each node's activation in an edge before passing it on to the next node) to support abitrary topologies
00:36	tomoj	working on implementing ken stanley's NEAT
00:37	wooby	tomoj: i would be very interested in seeing that, if you're willing to throw it up somewhere
00:37	piccolin1	technomancy, heck yes!
00:38	tomoj	wooby: it will be thrown up soon once I iron out a couple problems
00:38	wooby	awesome
00:38	tomoj	eventually want to do HyperNEAT
01:34	Clips	www.socialchat.co.uk or irc.socialchat.co.uk
01:34	Clips	Join now :) Swearing allowed
02:02	tomoj	is there a better way to write (fn [a b] [a b]) ?
02:03	hiredman	vector
02:03	tomoj	aha
02:03	tomoj	thanks
02:03	hiredman	,(vector 'a 'b)
02:03	clojurebot	[a b]
02:03	tomoj	I knew of vec, but not vector
02:04	hiredman	,((juxt (comp first list) (comp second list)) 'a 'b)
02:04	clojurebot	[a b]
02:04	tomoj	,(map vector [1 2 3] [4 5 6])
02:04	clojurebot	([1 4] [2 5] [3 6])
02:04	tomoj	nifty
02:05	tomoj	juxt is cool too
02:32	qed	man it sucks that have this friend who who goes out of his way to refuse that clojure is worthwhile
02:32	qed	that I have this*
02:33	qed	as usual, our drink turned into a discussion about programming, and i bring up how I think clojure is sort of the future programming language in that many of its features will be implemented into the mainstream at one point or another
02:34	qed	he is of the mind that if you aren't writing C you're wasting time, so I bring up abstraction and how it's important, but he seems dead set on this notion that concurrency and all of the things that clojure brings with it are glitter, without substance
02:35	qed	can anyone offer me anything in the way of perspective?
02:35	qed	am i being too bold when it comes to clojure?
02:37	qed	it just seems like the most elegant language ive ever used, how could anyone who hasn't used it have any idea?
02:37	arbscht	qed: if I were you, I'd have focused on enjoying the drink and not arguing about programming :)
02:37	piccolino	You'd be surprised what some people just can't be convinced of.
02:38	qed	arbscht: good advice, good advice, sigh, im not trying to convince so much as im just trying to gain some sort of recognition
02:39	qed	he's so ill-informed, though, that when i try to explain certain concepts he just dismisses them because he doesn't know them
02:39	arbscht	qed: write some useful code, it is more satisfying than recognition of the merits of a system in the abstract
02:39	piccolino	Punish him by letting him remain ignorant.
02:39	qed	piccolino: haha, arbscht: no doubt
02:39	tomoj	qed: has he written a multi-threaded C program?
02:40	qed	tomoj: he claims to know mutexes and thread locking, but i highly doubt he knows what lies in that clusterfuck
02:40	tomoj	ah
02:40	tomoj	have him try to write ants.clj in C
02:40	qed	now that is a gauntlet! :)
02:41	tomoj	keeping the idea that each ant runs on a separate thread
02:41	qed	his main argument was this:
02:41	tomoj	I guess maybe you could do it OK since ants.clj is not very complex
02:41	qed	the difference between making your program concurrent and running it fast with C is negligible
02:41	tomoj	I have never done much multi-threaded stuff
02:41	tomoj	hahaha
02:42	tomoj	did you remind him about the end of moore's law?
02:42	qed	tomoj: lol, omg that would have destroyed him
02:42	qed	i wouldn't have a friend anymore if i reminded him of that
02:42	qed	he would have been so butt hurt he probably would have stormed off with a curly bracket and a semicolon
02:43	tomoj	if program B runs faster than program A by a constant factor, but B only runs on one core, and A runs on 64 cores...
02:44	tomoj	I actually only have one core here :(
02:44	tomoj	but it pretends like it's two cores or something strange like that
02:45	tomoj	anyway I guess pretty soon everyone will have 8+ cores?
02:45	qed	tomoj: i just sent that to him via im
02:45	qed	his response is: "that's really a kernel thing, the kernel schedules the usage of all the processors"
02:46	qed	"if you create a thread it will be automatically scheduled and used on any available processors"
02:46	qed	"it's not like your code has to be any more complex"
02:47	tomoj	I conclude he has never done any serious multi-theaded programmming
02:47	tomoj	though neither have I, so what do I know
02:48	tomoj	but the problem is, of course, these threads will want to access the same memory (in C)
02:49	qed	his response: "yeah that's why you write thread-safe code"
02:49	tomoj	exactly
02:50	tomoj	the question is HOW
02:50	tomoj	in clojure it's easy
02:50	tomoj	in C...?
02:50	qed	he's clueless and stubborn
02:51	tomoj	eh
02:51	qed	i know him very well, he really lashes out against anything he doesn't know already
02:51	tomoj	guess it's like the Blub programmer
02:52	tomoj	everything I've ever done, I've been able to do with ruby/clojure/CL/java, so anything else is useless
02:54	tomoj	or rather, not any MORE useful than what I've got
02:54	qed	he just told me: "build me an operating system in clojure"
02:54	hiredman	qed: I will
02:54	hiredman	just give me some time
02:55	wooby	clojurebot nearly is
02:55	hiredman	http://research.sun.com/projects/dashboard.php?id=185
02:55	wooby	i saw that the other day, so awesome
02:55	hiredman	http://research.sun.com/spotlight/2008/2008-08-13_maxine.html
02:55	tomoj	hmm
02:56	hiredman	really, I want maxine, the guest os thing is just kind of cool
02:56	tomoj	is the test of a programming language's usefulness whether or not one can build an OS using the language?
02:56	hiredman	I know headius is looking at maxine for jruby
02:57	qed	dude, he just logged off: "but seriously, don't fucking tell me i have no perspective because i'm not balls deep in some obscure shit"
02:57	qed	"you're pissing me the fuck off"
02:57	qed	/quit
02:57	tomoj	hehe
02:57	qed	lol, one less friend
02:57	qed	more time to code
02:57	tomoj	developers can be quite defensive
02:58	qed	yeah, he's totally on that game, i welcome whatever i can find that's new and weird and obscure and challenging, etc.
02:58	qed	it's just my nature
02:58	qed	i truly don't understand the other end of that spectrum
02:58	qed	"what i have is good enough for anyone!"
02:58	qed	wtf?
02:58	qed	no. it's not.
02:59	qed	i think what pisses him off more than anything, is that he has a veryyyyy formal CS education, but he knows about the same as me
03:00	qed	so he feels like he has this platform to accept or reject ideas i propose when it comes to CS
03:01	qed	like he is the high court of CS, and his decree will be the law of the land
03:03	qed	idk, just another typical CS student who believes they wont need to learn anymore after they finish college
03:05	qed	universities are filled with so much garbage these days
03:05	qed	sigh, im rambling
03:05	qed	sorry all
03:21	sfuentes	qed: that's a bit extreme there
03:22	qed	sfuentes: ?
03:22	qed	the university bi?
03:22	qed	bit?
03:22	qed	I just meet a lot of undergrads these days who have no passion--
03:22	sfuentes	personally, i think a lack of a software engineering curriculum is at work
03:22	qed	that's certainly true
03:23	qed	it's like this weird hermaphrodite balance between djikstra and kay
03:23	tomoj	all of the CS majors I know are shitty developers
03:23	qed	(curriculum-wise)
03:23	qed	tomoj: same here
03:23	qed	like practically inept
03:24	tomoj	I like the CS curriculum just fine, though
03:24	tomoj	I enjoy abstract stuff that has no practical application :)
03:24	qed	there is less than 20% of CS majors I've seen who could hack
03:24	qed	like-- really... hack.
03:24	arbscht	irc channels are filled with garbage these days; I think a lack of coding is at work ;) (does clojure make programming useful things so trivial that you have time for this?)
03:25	qed	arbscht: bourbon, ginger beer, and bitters -- will do this to a man
03:25	tomoj	someone just peed off the balcony above me
03:25	qed	tomoj: welcome to halloween'
03:25	qed	i live in madison, wi
03:25	sfuentes	i think there should be a "software school" (similar to law and medical school) after one gets their CS degree.
03:26	qed	sfuentes: that's a really good idea
03:26	tomoj	not sure you can really learn much without actually doing
03:26	sfuentes	tomoj: but you will be doing
03:26	tomoj	if it's a school, you won't
03:26	qed	our CS program emphasized group work to get the "software development" "real world" scenario
03:26	qed	but it was BS
03:26	tomoj	unless the school is really just an internship
03:27	qed	half the time your partner wouldn't do anything
03:27	qed	and you'd pull the team
03:28	tomoj	I wonder how many clojure dev shops there are
03:28	qed	probably not many
03:28	qed	id love to be a part of one
03:28	sfuentes	tomoj: Residency training
03:29	tomoj	yeah, isn't that what an internship is?
03:30	sfuentes	internships are very general
03:30	sfuentes	not very supervised
03:30	sfuentes	but yes
03:31	tomoj	they can be useless I suppose
03:32	tomoj	I work for the IT dept of my university and there's very little source control, absolutely no testing, and absolutely no pair programming
03:32	qed	:X
03:32	qed	i have to go to bed, it's late
03:32	qed	but we will continue this tomorrow :)
03:33	qed	ciao tomoj, sfuentes
03:33	tomoj	co'o
03:34	sfuentes	night qed
03:34	sfuentes	tomoj: sad to hear
03:34	sfuentes	then again its IT
03:35	tomoj	I am now wondering whether the liquid that just fell from above onto my shoes is piss or a drink :(
03:56	arbscht	tomoj: don't evaluate it, it might have side effects!
03:59	tomoj	afterwards someone said "oh I didn't realize there was a drink next to you sorry" so I think I'm OK
04:58	yason	Is Clojure good at optimizing out multiple funcalls and replacing them with the value returned from a single funcall?
04:59	yason	(let [x (compute-something)] (list x x)) versus (list (compute-something) (compute-something)) ?
05:03	cgrand	yason: no because clojure can't generally know if a function is pure
05:05	yason	cgrand: No metadata for annotating pure functions? Ok, so (let ...) it is.
05:05	yason	Avoiding let would've made a more beautiful look though, in this case :)
05:06	cgrand	(repeat 2 (compute-something))
06:18	AWizzArd	How can I type hint a parameter to be a function object?
06:21	AWizzArd	ah okay, it's #^clojure.lang.Fn
06:28	AWizzArd	morning
06:31	modulus	hey, some good doc to read on the deployment of clojure and ides and stuff?
07:06	Kjellski	Gooood, morning!
07:24	AWizzArd	Hi the Kjell.
07:43	rhickey	deftype/defclass print is up - thanks to chouser!
08:01	blackdog_	hi, in slime/swank is there a way to add a directory of jars all at one time to the classpath, rather than enumerating each
08:05	_ato	blackdog_: (setq-swank-extra-classpaths '("~/somewhere/*"))
08:06	blackdog_	ah thanks :)
08:06	_ato	assuming you're using java 6, I don't think it works in earlier versions
08:06	blackdog_	yes
08:23	eevar2	with java 1.5 you'd do (setq swank-clojure-extra-classpaths (cons "/opt/clojure-contrib/clojure-contrib.jar" (directory-files "/opt/clojure-libs" t ".jar$")))
08:23	eevar2	damn old macbook.. :/
08:32	AWizzArd	chouser: cool, thanks for the printing
08:33	AWizzArd	rhickey: is the PAR branch (git) dependend on some external libs? Can it get merged with the NEW branch?
08:34	rhickey	AWizzArd: it depends on jsr166y
08:35	AWizzArd	http://www.jcp.org/en/jsr/summary?id=166
08:35	rhickey	the dep is here: http://github.com/richhickey/clojure/downloads
08:36	rhickey	http://cloud.github.com/downloads/richhickey/clojure/jsr166y.jar
08:40	AWizzArd	Do you think the .class files from that .jar may get included in future versions of Clojure?
08:49	rhickey	AWizzArd: jsr166y is not compatible with Java 5
08:51	AWizzArd	I see
08:53	chouser	bah
08:53	rhickey	chouser: good morning to you too :)
08:53	chouser	rhickey: sorry about the load order. I forgot to actually try building clojure before putting the patch up.
08:54	chouser	heh. good morning. :-)
08:54	rhickey	np
08:54	notallama	jsr166y.jar seems to be missing things. namely, jsr166y.forkjoin.*
08:58	rhickey	notallama: compared to what? there may have been some refactoring since I snapshotted, but that is all that par needs
08:58	rhickey	forkjoin was moving target at the time
09:00	rhickey	so, the new deftype/defclass theory is, if you want IPersistentMap support generated, just specify it in the interface list but don't implement it
09:00	rhickey	by default only hash,equals, metadata and lookup are included
09:02	notallama	rhickey: compared to what parallel.clj is asking for. (import '(jsr166.forkjoin ...))
09:03	rhickey	notallama: parallel.clj was written to a very old jsr166y, available here: http://clojure.googlegroups.com/web/jsr166y.jar
09:04	rhickey	the old and new libraries are incompatible, that was the last version to work with Java 5
09:05	rhickey	so par will replace parallel at some point
09:05	hoeck	rhickey: what about adding IObj/IMeta to the list of magically implemented interfaces?
09:05	rhickey	hoeck: meaning no default generation?
09:05	hoeck	rhickey: or is this a must so that the type tag works?
09:06	hoeck	rhickey: yes, say for some extreme lightweigt types, like database-rows
09:06	rhickey	who doesn't want metadata?
09:06	notallama	oh, so parallel isn't par. that explains things
09:07	rhickey	hoeck: seems like a premature optimization
09:07	rhickey	as database rows flow through an app, you sure might want to remember what table they came from etc
09:07	hoeck	rhickey: okay, guess I will measure then :)
09:07	rhickey	hoeck: certainly only a space issue
09:08	hoeck	rhickey: ok, point taken, but whats the reason to optionally implement IPersistentMap?
09:09	rhickey	but there will at lest be a consistent construction story, regardless of which interfaces are implemented - fields you asked for + meta + extmap, the latter 2 defaulting to null
09:09	AWizzArd	Btw, what advantages does defclass offer over deftype?
09:10	chouser	AWizzArd: named class and (maybe) more speed
09:10	rhickey	hoeck: IPersistentMap brings a ton of semantics - it essentially makes your type/class a collection - collection, Counted, Seqable, associative etc
09:10	AWizzArd	chouser: named class - so one can add type hints in functions that take defclassed objects?
09:10	chouser	I noticed defclass only made one ctor.
09:11	chouser	AWizzArd: well, so that Java can use it by name, find the class file by name, etc.
09:11	rhickey	chouser: yes,I need to fix that, copied from deftype
09:13	chouser	I couldn't see where the ctors were specified
09:13	rhickey	defclass docs
09:14	chouser	I mean I didn't see where create-defclass* was told what ctors to create so I thought maybe it was all in Compiler ...and promptly stopped digging.
09:15	rhickey	chouser: yes, compiler does the ctor from fieldslist supplied to defclass*
09:15	chouser	yeah, ok. will deftype classes get 2 ctors also, or will there have to be another arg to defclass*?
09:17	rhickey	chouser: no, there's only one ctor, 2 factory functions - the docs are wrong because I copied factroy-ctor from deftype docs to defclass docs
09:18	chouser	ahhhh. ok.
09:18	rhickey	right now there isn't accessibility to the deftype ctor for code not inside deftype
09:18	chouser	right
09:18	rhickey	becasue the actual classname doesn't escape
09:19	rhickey	so, dissoc of base field --> ordinary map not of type?
09:19	rhickey	I like that better than error, if e.g. get of non-present is going to return nil
09:21	chouser	doesn't it seem a little scarey that all the behavior (besides IPersistentMap) could change on dissoc?
09:21	rhickey	chouser: it's a different object
09:21	chouser	hm -- regular map but keep the type :tag?
09:22	rhickey	chouser: it's not the same type anymore
09:22	rhickey	if you are calling dissoc you are treating the class as a collection/data
09:22	rhickey	i.e. more generically
09:23	rhickey	code in set or relational libs might do that just as a matter of transformation
09:23	rhickey	this thing without those fields merged into that thing
09:24	rhickey	shouldn't blow up if this-thing is from a deftype
09:30	AWizzArd	Is it/will it be possible to define a hierarchy with deftype/defclass?
09:30	rhickey	AWizzArd: a hierarchy of concrete types ? no
09:33	hoeck	rhickey: but a hierarchy of interfaces?
09:33	AWizzArd	Maybe one can use derive and isa??
09:34	hoeck	and how do I define Interfaces? with gen-interface?
09:35	rhickey	hoeck: it's possible, and I've done it, but it's almost always better not to. You end up doing in in Java because you couldn't say foo(this-and-that-type x), maybe now with generics you can
09:36	rhickey	hoeck: there will be a definterface that matches defclass/type, but same idea, and same AOT
09:36	rhickey	AWizzArd: you should avoid hierarchy when you have other tools to model overlapping concerns - like protocols :)
09:40	jdirks	Hi there anyone willing to answer my noob questiosn?
09:42	jdirks	How do i make a set from a list? #{ (list 1 2 3 4) } makes a set that contains 1 list element.... not what I want.
09:42	chouser	,(hash-set (list 1 2 3 4))
09:42	clojurebot	#{(1 2 3 4)}
09:42	chouser	d'oh
09:42	chouser	,(set (list 1 2 3 4))
09:42	clojurebot	#{1 2 3 4}
09:44	hoeck	rhickey, so the clojure interface-hierarchy will be defined in terms of `protokolls', cool
09:45	esj	is there a reference out there explaining protocols in this sense ?
09:45	AWizzArd	rhickey: ok, I still don't have protocols on my radar yet.
09:46	AWizzArd	esj: http://www.assembla.com/wiki/show/clojure/Protocols
09:46	esj	AWizzArd: much obliged
09:50	jdirks	I notice set creates a PersistentHashSet and sorted-set creates a PersistentTreeSet. Is there a way to create a PersistentTreeSet with a function like set that can take a list?
09:50	_ato	,(apply sorted-set (list 1 2 3 4))
09:50	clojurebot	#{1 2 3 4}
09:51	_ato	,(type (apply sorted-set (list 1 2 3 4)))
09:51	clojurebot	clojure.lang.PersistentTreeSet
09:53	jdirks	Anyone know why 'set' can be called directly but union only works with 'clojure.set/union' ? It seems a bit inconsistent.
09:56	chouser	jdirks: you're asking why some set-related functions are in clojure.core and others are in clojure.set ?
09:57	jdirks	I know it is just a design issue but it seems that set and union really should go together.
09:58	jdirks	I was wondering if there was some real reason for the different name space
09:58	jdirks	especially since it is not documented that way at http://clojure.org/api#union
09:59	_ato	it is, scroll up and you'll see it's under a clojure.set heading
10:00	rhickey	jdirks: actually, that is in it's own section, per namespace, just not great graphically
10:00	chouser	the basic functions you need to work with the set datatypes are all in core -- set, hash-set, sorted-set for creation; get, contains?, conj, seq for working with existing ones.
10:00	rhickey	above difference - clojure.set
10:01	jdirks	oops sorry
10:01	rhickey	chouser: thanks for deftype print - so much nicer to play with now!
10:01	jdirks	i guess if you only use search on that page you do not notice it is organized that way.
10:01	chouser	the clojure.set namespace has "extra" stuff for working with set objects -- mostly relational things (join, select) and their support functions, but some others as well.
10:01	gerry_	hello
10:01	chouser	rhickey: heh, np.
10:02	chouser	rhickey: will you be wanting a reader?
10:02	gerry_	my os crashed, i have to reinstall it to check out clojure-new and try again
10:02	rhickey	so, (deftype Foo [a b c d e] [IPersistentMap]) in order to get associative/expando?
10:03	chouser	rhickey: is that instead of any opt-out flags?
10:03	rhickey	chouser: at some point I guess at least print-dup/readable, but complications exist regarding the availability of the supporting code needed to create instances
10:03	rhickey	chouser: yes, instead of opt out or int
10:04	rhickey	in
10:05	chouser	can we have clojure.lang.* imported by default? or maybe shortcut names for use in the deftype/defclass interfaces list?
10:06	chouser	(deftype Foo [a b c] [:map :stack :reversible java.util.Foo])
10:09	Kjellski	Anyone that saw a good comparison for Clojure ans Scala? Where the main differences are?
10:10	gerry_	hmm
10:10	chouser	Kjellski: Clojure, when compared objectivly and rigerously to Scala, has more good and less bad
10:10	_ato	hehe :)
10:11	Kjellski	smile write this in the #scala and get on with the flamewar right?
10:11	rhickey	chouser: I like the abstracting away of the interfaces in that, but it has to be clear what you get, and what will conflict if self-defined
10:11	jdirks	I would say Scala is Java++. Clojure is a functional language that runs on the JVM.
10:11	magnet	chouser, that's objective
10:12	gerry_	kjellski: search on stackoverflow.com
10:12	chouser	magnet: exactly. and rigorous
10:12	Kjellski	gerry_ : thanks, nice tip.
10:13	magnet	Kjellski, my comparison is: Clojure is a Lisp. Scala is not. If you like Lisp, use Clojure. If you prefer ML use Scala.
10:14	rhickey	chouser: :keys in interface list might be useful as an extension point as well
10:14	chouser	Kjellski: Clojure has: dynamic types, macros, smaller core, more emphesis on immutability, richer concurrency semantics, more broadly useful seq abstraction.
10:15	Kjellski	chouser : And what of that does Scala have not?
10:15	chouser	rhickey: yeah, the mapping of short key to interface name isn't terribly obvious. auto-importing clojure.lang would be less magical
10:16	Kjellski	chouser : Okay, macros I know... ^^
10:16	chouser	Kjellski: those were as compared to Scala
10:16	Kjellski	chouser : you really think, that is all better in clojure?
10:17	chouser	Well, Scala is staticlly typed and has no macros, so that's easy.
10:17	Kjellski	k
10:17	jdirks	Is there any work being done on getting some sort of stack trace when you hit an exception? Especially since I am new I find that I need to test every little bit of logic separately because if there is a runtime exception I can not find where it happened exactly.
10:18	jdirks	(This was never a problem when using Python)
10:18	_ato	jdirks: huh? you should be getting a stack trace, with the file and line number
10:18	chouser	The Scala type system is quite complex, the compiler would have to be more complex, and I think the standard library is larger, so you can file all that under "larger core"
10:18	Chousuke	you may need to use (.printStackTrace *e) after the exception
10:19	Chousuke	or, even better, use the contrib stacktrace pretty-printing thing to do that.
10:19	jdirks	ok I may have missed something. Is there a long to how to do that?
10:19	raek	jdirks: if you are using emacs, I recommend slime over inferior-lisp
10:19	chouser	Kjellski: Scala does support immutable locals and has some immutable collections, but it also has mutable locals and mutable collections. Clojure provides only immutables -- so "more emphesis on immutability"
10:19	jdirks	I currently use the Eclipse plugin
10:20	Kjellski	chouser : don´t stop, I´m reading ^^
10:20	raek	I'll guess it depends on the IDE you are using
10:20	cemerick	rhickey: perhaps you could relent on open imports just for clojure.lang. Maybe an :import-clojure form in ns?
10:20	magnet	chouser, the fact is in both Clojure and Scala you can fall back to Java and end up with mutable structures. Scala made the choice to provide some (Scalified) of its own, whereas Clojure put a barrier and said "here be dragons; we do not compromise" :)
10:20	Chousuke	also: scala syntax. :-(
10:21	ambient	well, clojure has arrays for fast mutable access, which for my purposes are a bit clunky
10:21	magnet	Chousuke, a lot of people would say; also: clojure syntax :-( ;)
10:21	Chousuke	magnet: but they would be mistaken!
10:21	rhickey	cemerick: I really don't want people to marry all of clojure.lang, or possibly any of it
10:21	chouser	Kjellski: If you want to write multithreaded apps, Clojure allows you to choose for each taks between: agents (a bit like Scala's actors), atoms, refs (the main STM hook -- no such thing in Scala), vars (easy access to thread-local data) -- thus "richer concurrency semantics"
10:21	jdirks	Then again you can do OO in Scala.
10:21	Chousuke	well, except for a few things
10:21	Chousuke	#() can get ugly sometimes
10:22	magnet	chouser, I hear Scala developers are planning for a STM in 3.0
10:22	cemerick	OK. I was just reacting to chouser's ":map :stack :reversible" example.
10:22	rhickey	cemerick: but the interfaces could be auto-included with the java.lang bits
10:22	magnet	chouser, but I agree with you that chouser provides more support currently
10:22	chouser	magnet: yes, and I appreciate the pragmatism of both. But when speaking of the language itself I think it's still accurate to say Clojure puts "more emphesis on immutability"
10:22	chouser	right
10:23	rhickey	cemerick: one nice aspect of :map etc is that it doesn't dictate that the support will be provided via interfaces. Once those features are supported via protocols they could be provided wither way
10:23	raek	Kjellski: macros are one of my favorite things in lisps. if the code is starting to look complex, simplify it with macros
10:23	Chousuke	it's not even possible to use most of the concurrency stuff if you're not using immutable data structures :/
10:23	markgunnels	adf
10:23	raek	(a (b (c (d (e))))) => (-> e d c b a)
10:23	magnet	raek, macros are also a thing a lot of people tend to get wrong in Lisp
10:24	magnet	"with a great power comes great responsibilities ;p"
10:24	raek	hehe
10:24	raek	that's true...
10:24	chouser	Kjellski: that leaves the seq abstration. Scala does have lazy Streams, but they're their own thing with a few methods. Clojure's seq library is pervasive and shouldn't be underestimated in it's power.
10:25	magnet	chouser, actually that changed in 2.8 with the new scala collections
10:25	rhickey	cemerick: so, you are ok with (deftype Foo [a b c d e] [IPersistentMap]) in order to get associative/expando?
10:25	Chousuke	but macros are one tool that you want to have.
10:25	cemerick	rhickey: oh, that's just fine :-)
10:26	esj	the only trouble with Clojure, is that for beginners, such as myself, learning Clojure, requires learning three languages (clojure, java, lisp) more or less concurrently, which is a mild challenge
10:26	chouser	Kjellski: every collection type knows how to be viewed as a seq, the set of functions that work on seqs are powerful and succinct, and all the persistent collections can be built from seqs. It's really a beautiful thing for expressing data transformations, and you get to use it just about anywhere.
10:26	Kjellski	chouser : Thanks a lot for this nice wrappup! I´ll definitely save this log. That´s what I was looking for.
10:26	raek	is there any way to read, say words or other tokens, from a java InputStream using a seq?
10:26	Chousuke	sure.
10:27	chouser	magnet: oh, which changed? I've been away from Scala a while.
10:27	magnet	chouser, pretty much everything in collections. Odersky remade them more or less from scratch
10:27	chouser	Kjellski: oh, and a final killer feature for me that Scala just can't touch: commit access. ;-)
10:27	Chousuke	first you read a seq of characters, then send that through a filter which tokenizes the seq, and then you have a seq of tokens :P
10:27	rhickey	cemerick: and dissoc of base key yielding non-type map?
10:28	cemerick	rhickey: yes, definitely. It's probably an opinionated choice w.r.t. type theory, but I think it's the right one, anyway.
10:29	Kjellski	chouser : Sure, that´s pretty nice... but there is no way to get involved in Scala?
10:29	magnet	Kjellski, define "get involved"?
10:29	magnet	ah
10:29	Kjellski	got it?
10:29	magnet	well sure, there are some external committers for scala too :)
10:29	raek	Chousuke: how do I get a seq from a stream?
10:29	rhickey	hmm... 30+ interfaces in clojure.lang
10:29	magnet	Kjellski, didn't see chouser's line :)
10:29	chouser	Kjellski: oh I'm sure there is, but I'm "in" here already. :-)
10:29	raek	is there anything like that in the core api?
10:29	Kjellski	magnet : okay.
10:30	Chousuke	raek: well, for example, (repeatedly #(.read stream))
10:30	raek	ah, ok. that was pretty simple
10:30	Kjellski	chouser: And, please stay here =)
10:30	Chousuke	that produces ints though
10:30	magnet	Kjellski, a huge argument in favor of Scala is that, I believe it's easier to get Java/C++ programmers to move to Scala than to Clojure, at least currently.
10:30	magnet	but that's only my personal experience
10:31	Chousuke	magnet: I don't think that's a real pro, though :/
10:31	Kjellski	magnet : I think so too, but the hard time I have now, will be forgotten when I´m used to write Lisp code... I just need the "paranthesis from my father" ^^
10:31	magnet	Chousuke, well it's a pro when you get your boss to agree to use Scala on a project because "even if I'm gone, people can maintain it, it's easy to read, look" :)
10:31	chouser	Kjellski: heh, no worries. I've tended to bail on languages pretty quickly in the past, but rhickey got his hooks into me.
10:32	cemerick	magnet: that only matters if you need to go hire lots and lots of programmers. Warm bodies in abundance isn't necessarily an objective.
10:32	magnet	Kjellski, a more elegant weapon for a more civilized age?
10:32	magnet	from*
10:32	_ato	mmm.. and if you hire good programmers they should be able to pick up anything pretty easily
10:32	Kjellski	magnet : Oh please, got the link? I´ve searched for this but couldn´t find it again...
10:32	Chousuke	It's funny how people always focus on the parentheses with lisp syntax.
10:33	Chousuke	they just move around a bit. why does that matter so much? :(
10:33	chouser	Chousuke: since you asked
10:33	chouser	...I'll tell you why it matters.
10:33	Kjellski	Chousuke : That´s just an "insider" from xkcd... ^^ nevermind
10:33	magnet	cemerick, depends on the shop you work at. Here it's Java only, and earlier a colleague came into my office asking for "the Scala guy" .. I have hope for a move to Scala, but I wouldn't dare dream to Clojure (even if I'd enjoy it)
10:34	magnet	Kjellski, the xkcd link?
10:34	Kjellski	magnet : yap
10:34	chouser	in C-like languages, foo(...) always means "call foo" or possibly use a builtin syntax thing called foo
10:34	raek	http://xkcd.com/297/
10:34	Kjellski	raek: thanks!
10:34	jdirks	Also for os clojure/lisp noobs it would be nice if the API page would contain (or a link to) a minimal example for every function with its intended use.
10:35	chouser	in C-like languages, the only other way parens are used are for grouping and syntactially it's clear they're not calling anything.
10:35	Kjellski	jdirks: : That´s definitively signed from me.
10:35	cemerick	magnet: right, that was mostly my point -- it's very, very hard to determine what's "best" w.r.t. language choice, because circumstances and premises vary so much.
10:35	Chousuke	chouser: hmm, I guess that makes sense. in Lisp you have parens everywhere so I suppose it looks messy to the uninitiated.
10:36	raek	you can see that strip on several office doors at the Institution of Computer Science here at Linköping University
10:36	Chousuke	chouser: I think Clojure suffers a lot less from that problem than CL or Scheme do, though. :)
10:36	chouser	In lisps (foo) could mean just about anything. I could be invoking a function or special form, or it could be deep in a nested form and just be a symbol in a list, or (in non-Clojure) it could be declaring a local named foo or be a special arg to a macro or ... who knows what!
10:37	chouser	Chousuke: yes, less. But it can still mean a fn or method def (in fn, letfn, proxy and now defclass and deftype) or a friggin' group of test cases in 'case'
10:38	Chousuke	I must say I like the scheme syntax for function definition, even though it has this "confusing" use of parens... (define (foo x y) ...) just makes sense.
10:38	cemerick	chouser: you don't like the parens in case, eh? :-)
10:39	chouser	cemerick: how'd you guess?
10:39	_ato	I don't have much of a lisp background (came from c, python, ruby etc) and I found Clojure a bit easier to read than other lisps because of the vector-syntax like (defn foo [a b c] whatever), makes things stand out more.
10:39	chouser	_ato: exactly. me too.
10:39	Chousuke	chouser: with fn, proxy, defclass/deftype I can forgive it because they all use it in a similar way (method/function definition)
10:40	Kjellski	I love the example from Stuarts book, where he showed the (.. ) macro just producing less parens than native java itself... that´s where I lost my fears about them I think...
10:40	chouser	Kjellski: ah, that's good to hear.
10:42	Chousuke	so Rich decided on lists for case syntax?
10:42	Kjellski	chouser: The problem for me was, the combination of different semantics for parens and exactly same looking data structure in "old" lisps... just like _ato said.
10:43	Chousuke	with Scheme you can actually use [] and {} interchangeably with ()
10:43	Chousuke	waste of good characters :P
10:43	chouser	Chousuke: that's what's in branch 'new' but perhaps it's not in stone yet.
10:43	cemerick	that always screws me up now
10:43	cemerick	chouser: keep hope alive!
10:44	raek	which lisp has "superparens"?
10:44	raek	like: ( ( ( ( ]
10:44	Kjellski	raek, that sounds pretty confusing...
10:44	Chousuke	but in elisp [...] actually is (vector ...)
10:47	djork	PLT Scheme uses [] interchangeably with ()
10:47	djork	but I've never heard of superparens
10:47	djork	sounds nice though
10:47	raek	I guess superparens were invented before highlight matching paren functionality of editors ;)
10:47	chouser	Franz Lisp used ] to close off all open parens
10:47	djork	heh heh
10:47	djork	yeah
10:48	steiger	hm
10:48	steiger	super parens seems to be fun
10:50	Kjellski	I don´t get it, that makes only sense if they´re not used in a better way, like representing another data structure?
10:50	chouser	Kjellski: right
10:52	Kjellski	chouser: "Righty thenn..."
10:53	jdirks	Noob Question: I have a vector and for each element in it i need to call a function like (myfn index value) how should I do that?
10:53	AWizzArd	map
10:53	raek	does anyone know how to change coding system in slime?
10:53	AWizzArd	,(map inc [10 20 30])
10:53	clojurebot	(11 21 31)
10:53	jdirks	I need to know the index in when calling the function
10:54	raek	on startup, slime says: (swank.swank/start-serve "/tmp/slime.24462" :encoding "iso-latin-1-unix")
10:54	AWizzArd	,(use 'clojure.contrib.seq-utils)
10:54	clojurebot	java.lang.IllegalStateException: shuffle already refers to: #'sandbox/shuffle in namespace: sandbox
10:54	AWizzArd	,indexed
10:54	clojurebot	#<seq_utils$indexed__697 clojure.contrib.seq_utils$indexed__697@ec0f07>
10:54	raek	I most definitely don't want to use latin1...
10:55	_ato	I think languages like Python are always going to have a small readability advantage over lisps as they read more like english, but lisps have huge benefits for writability -- besides the obvious macros, editor support (like eval hotkeys) works much better. Curly brace languages are neither really much more readable, nor writable, it's just everyone is used to them. :-P
10:55	AWizzArd	,(map #(vector :index (first %) (inc (second %))) (indexed [10 20 30]))
10:55	clojurebot	([:index 0 11] [:index 1 21] [:index 2 31])
10:55	rhickey	so, on the parens in case thing. If you want parens to always be 'calls', then how do you match lists? (case '(:a :b) (:a :b) "found" ...). parens still are list data designators, and the first of each clause is unevaluated data by definition (i.e. not a call)
10:56	_ato	A friend had previously tried to convert me (as a Python/Ruby user) to common lisp. I wrote a few programs and liked macros and the editor support, but I found the syntax difficult, but the clojure vector thing improved it enough to convert me.
10:57	chouser	rhickey: literal sets were mentioned as an option
10:57	jdz	_ato: which vector thing?
10:58	rhickey	so the desire to 'save parens for calls' eliminates their use here and elsewhere for data matching. The fact that vectors usually work for both has made that less of an issue, but it's a big deal to lose one of the 3 matching delimiter pairs
10:58	_ato	jdz: (let [x 1]) instead of (let ((x 1))) and (defn foo [a b] ...) instead of (define (foo a b) ...)
10:58	rhickey	chouser: that's still a possibility
10:58	Chousuke	_ato: and for lisps there's paredit :P
10:59	jdz	_ato: what's the difference?
10:59	rhickey	one problem is that almost everywhere else syntax calls for a logical set, a vector is used instead
10:59	rhickey	using sets in case will beg the question as to why they aren't used in similar situations elsewhere
11:00	chouser	yes, it's a big deal to lose parens for other meanings, and futile to try to remove them completely -- you can always have deeply nested quoted structures or user macros that use literal lists as non-calls.
11:00	_ato	jdz: it makes it more obvious that [x 1] is not a function call, it's an assignment when you're reading the code
11:00	jdz	i personally have very mixed feelings about the property-list kind of specifying things (keys not being anything special)
11:00	Chousuke	_ato: Instead of manipulating lines of code, you manipulate expressions. It's simple, but... Once you learn it, there's no going back :P
11:00	jdz	_ato: not really. [x 1] might as vell be a vector acces.
11:01	jdz	and by property-list kind i mean undelimited pairs of things
11:01	chouser	And honestly it probably won't matter much to me personally anymore -- I'm in deep enough with the lispy syntax now to not be terribly confused by usages like for case. I can even read scheme somewhat more easily now.
11:01	jdz	so i prefer CL's style for both LET and COND
11:01	_ato	Chousuke: yeah, I'm a big paredit fan
11:02	Chousuke	I sometimes still open vim for quick edits of lisp code and it always feels silly to type the closing parentheses
11:02	chouser	But I do think it actually made a significant difference between the amount of effort it took to try to use CL vs. Clojure
11:03	rhickey	I will say that case was definitely a problem for me when I was learning CL, the whole unevaluated position thing, how symbols were used literally to match symbols, not referents. Of course, they don't even support composites as keys there
11:03	_ato	jdz: that's true. As a previous non-lisper though, it's just easier to adapt to for some reason. I'm used to assignments and method definitions being visually distinct. I never confused it with literal vector syntax for some reason
11:03	rhickey	chouser: don't get me wrong, Clojure definitely tries to use [] for non-calls as much as possible, and gets rid of lots of grouping
11:04	Chousuke	and there's always going to be a closing paren anyway, so the editor should just take care of it :P
11:04	jdz	_ato: yes, that's subjective.
11:04	chouser	rhickey: right. it's clear that was a goal and has been sufficient so far.
11:04	chouser	rhickey: 'proxy' and even multiple fn bodies are used rarely enough that beginners can look at a lot of code before having to deal with them.
11:05	rhickey	if [] and () were both supported as keys, would people expect case to differentiate by type?
11:05	rhickey	because that would ruin case perf
11:05	Chousuke	chouser: and really, ([foo bar] stuff) is probably not going to look like a function call to a newbie anyway. they'll just go "what's that vector doing there?"
11:06	chouser	Chousuke: right
11:06	_ato	jdz: yeah, indeed, I'm sure it depends completely on what you're used to, but it gives Clojure a better chance at converting non-lispers, which is a good thing.
11:07	jdz	_ato: that's for sure -- non-lispers are used to syntax sugar :)
11:07	rhickey	well, the most important thing is that people kick the tires with deftype case etc. Please try 'new' branch everyone!
11:07	jdz	i'd say even addicted :)
11:07	Chousuke	[] and {} are not syntactic sugar though
11:08	Chousuke	nor is #{} (I always forget sets)
11:08	tomoj	how not?
11:08	jdz	Chousuke: depending on usage. in case of let and bindings they are.
11:08	jdz	*other bindings
11:08	jdz	but then, CL has vectors, too: #(1 2 3)
11:08	Chousuke	jdz: not really. for example, destructuring would be slower if lists were used instead of vectors
11:09	jdz	Chousuke: nah, implementation details.
11:09	Chousuke	they're real vectors, as syntax. not shortcuts for (vector foo bar)
11:09	Chousuke	that means that in your macro you can use nth on the vector and it's constant time.
11:09	jdz	#(1 2 3) is also a real vector, and not a shortcut.
11:10	jdz	but it is offtopic anyway
11:11	Chousuke	so you will be able to manipulate a vector if you do (somemacro #(foo bar))? and somemacro takes a single parameter :)
11:11	jdz	Chousuke: but of course
11:12	jdz	Chousuke: if foo and bar are bound, that is
11:12	Chousuke	why do they need to be bound? :/
11:12	jdz	Chousuke: same reason as in Clojure, they would be treated as variables
11:13	jdz	Chousuke: oh wait a second.
11:13	_ato	hehe so Clojure is like a nicotine patch for syntax sugar... weaning you off overcomplicated, sugared syntax but still with enough variety to prevent withdrawl symptoms. :-P
11:13	Chousuke	if #() were just a reader expansion to (vector foo bar) you'd get a list for manipulation in your somemacro
11:13	jdz	Chousuke: it's a macro, so yes, you'd get a vector of 2 elements
11:14	jdz	Chousuke: symbol FOO and symbol BAR
11:14	Chousuke	right.
11:14	Chousuke	probably no-one uses vectors for macro syntax in CL though.
11:14	Chousuke	#() looks a bit ugly. :P
11:15	jdz	Chousuke: well, yes it does. that's why i don't like it in Clojure :P
11:15	jdz	but in CL it is used very rarely
11:15	rhickey	Clojure: (let [a 1 b 2 c 3] [a b c]) CL: (let ((a 1) (b 2) (c 3)) `#(,a ,b ,c))
11:16	cemerick	Chousuke: really? I quite like it. What would a good alternative be, in a parallel universe?
11:16	Chousuke	cemerick: I don't think there's anything better
11:16	_ato	in a parallel universe keyboards would have a lambda character instead of # :p
11:16	Chousuke	I think #() fits quick lambdas better than vectors, anyway
11:16	jdz	rhickey: not really. (let ((a 1) (b 2) (c 3)) #(a b c))
11:17	djork	I appreciate the fact that I can use evenly-counted vectors instead of (() () ())
11:17	chouser	jdz: nope
11:17	rhickey	jdx, no #(a b c) is a vector of 3 symbols, unevaluated
11:17	Chousuke	the # kind of says "make the next expression a function"
11:17	jdz	rhickey: ye, sorry. my CL is still swapping in ;)
11:17	steiger	_ato: in PLT Scheme, you can type the lambda character with CTRL+Z on their IDE
11:17	steiger	it works as syntactic sugar to the keyword lambda
11:18	steiger	i think
11:18	Chousuke	heh
11:18	tomoj	my emacs does that when I type lambda
11:18	Chousuke	yeah, mine too :P
11:18	tomoj	but no "lambda" in clojure anyway, and "fn" is short enough
11:18	rhickey	jdz: that example highlights the difference - vectors have interpretation as syntax during evaluation in Clojure, in CL they are just a reader thing, embeds a vector in your code
11:18	steiger	fn is fine ;)
11:19	jdz	rhickey: yes, differences are ok, as long as there are reasons behind them. keep up the wonderful job you're doing :)
11:20	jdz	i did not want to drag CL in here, so, back to the scheduled regular Clojure discussions.
11:21	Chousuke	I wonder what it would take for Clojure to support continuations :/
11:22	steiger	is github down or something? what happened to richhickey/clojure ?
11:22	Chousuke	:o
11:23	_ato	yeah github's offline for maintainance
11:23	Chousuke	I wonder if they're finally going to make it faster.
11:23	steiger	oh yeah, i read it on the main page
11:23	_ato	"We are experiencing some heavy load on the frontends caused by a vast number of processes waiting for responses from the backend. On it."
11:24	Chousuke	fortunately github is not central to development :D
11:25	_ato	steiger: you can still clone with: (defn readline-seq [rdr] (lazy-seq (cons (.readLine rdr) (readline-seq rdr))))
11:25	_ato	gah
11:25	_ato	wrong paste
11:25	_ato	I meant: git clone git://github.com/richhickey/clojure.git
11:25	steiger	_ato: i was wondering how the hell that would clone a git repo ;P
11:26	_ato	well... I guess if you redefine defn in a really strange way... :p
11:34	chouser	,(macroexpand '`[1 2 3])
11:34	clojurebot	(clojure.core/apply clojure.core/vector (clojure.core/seq (clojure.core/concat (clojure.core/list 1) (clojure.core/list 2) (clojure.core/list 3))))
11:36	Chousuke	why does it include the seq call? :/
11:36	_ato	wow.. that's weird
11:37	_ato	,(macroexpand ``[1 2 3])
11:37	clojurebot	(clojure.core/apply clojure.core/vector (clojure.core/seq (clojure.core/concat (clojure.core/list 1) (clojure.core/list 2) (clojure.core/list 3))))
11:37	_ato	,(macroexpand `'[1 2 3])
11:37	clojurebot	(quote [1 2 3])
11:38	Chousuke	syntax-quote is completely read-time so the macroexpansion is weird :)
11:38	djork	interesting
11:38	chouser	I look forward to that changing.
11:38	Chousuke	but that's what it has to expand to, because it has to build the structure at runtime.
11:39	Chousuke	so even a macro implementation will eventually produce something like that.
11:39	Chousuke	chouser: my macro sq already works but it probably has some corner cases. :/
11:39	chouser	Chousuke: hm, good point.
11:39	_ato	ah right
11:39	_ato	it's because of splicing
11:39	chouser	the concat is to leave room for splicing
11:39	chouser	right
11:40	Chousuke	what I don't get is why there's teh seq after the concat
11:42	_ato	ret = RT.list(APPLY, VECTOR, RT.list(SEQ, RT.cons(CONCAT, sqExpandList(((IPersistentVector) form).seq()))));
11:42	_ato	hmm
11:43	Chousuke	heh.
11:43	chouser	It's a java macro!
11:43	Chousuke	a clojure reader macro written in Java :P
11:44	chouser	all the clojure reader macros are written in java
11:44	Chousuke	well, yeah.
11:44	Chousuke	hmm
11:44	Chousuke	I think I'll try running the contrib test suite with my sq-macro-clojrue
11:44	Chousuke	clojure
11:45	_ato	although you think the reader could just expand it to (backquote whatever) and then you could define it in clojure
11:45	chouser	so concat always returns a seq anyway. so (seq (concat ...)) can only be to get nil on empty, right?
11:45	chouser	_ato: yes, that's the plan
11:45	_ato	yeah but (apply vector '()) and (apply vector nil) behave the same
11:46	_ato	maybe it's from pre new lazy
11:46	_ato	or sometime even earlier when things behaved differently
11:52	avital	Hi. To whom do I report broken links on http://richhickey.github.com/clojure-contrib/monads-api.html#monads/writer-m?
11:53	chouser	avital: I think github is just having problems at the moment.
11:55	avital	Ok cool. And for another question, can anyone point me to an example of using the update-state function from the clojure-contrib monads library? I feel like if I only see one working example it may all fall into place.
12:06	AWizzArd	avital: look at fnparse
12:06	avital	AWizzArd: Thanks, GitHub is broken now, I'll take a look later.
12:06	AWizzArd	at github, http://github.com/joshua-choi but also down right now
12:07	avital	And do we all agree that monads are probably the craziest and most amazing thing in the world or something?
12:07	chouser	are they amazing?
12:08	chouser	I need something to sell me monads the way "on lisp" sold macros.
12:09	_ato	yeah, to me they just seem to overcomplicate things without any major benefits
12:09	avital	chouser: I'm going to try to make this thing that transforms all code into monad comprehension that allows you to attach arbitrary monad transformations thus allowing logging, profiling, exception handling and millions of other things just by adding one keyword each.
12:10	rhickey	I'm thinking about requiring . before method names in reify/defclass/deftype
12:10	avital	No really. Monads are probably the most important thing or something.
12:10	chouser	rhickey: in the syntax for defining the method?
12:11	rhickey	because right now (deftype/reify .... (seq [] (seq "foo"))) the second seq is core/seq
12:11	rhickey	chouser: yes: (.seq [] (seq "foo"))
12:11	srader	I've done a bit of micro-benchmarking with deftype/defclass. (time (dotimes [_ 10000000] (:age p))), where p is either deftype-obj, defclass-obj, PersistentStructMap, or PersistentArrayMap. I get PersistentStructMap slower (2x) than deftype-obj, which is slower (1.5x) than PersistentArrayMap, which is slower (4x) than defclass-obj.
12:11	srader	defclass is very fast!
12:11	chouser	rhickey: I think that sounds nice.
12:12	hiredman	avital: http://tinyurl.com/ylk8lys
12:12	_ato	rhickey: regarding " *
12:12	avital	hiredman: AMAZING
12:12	_ato	Universal field identifiers" ie the RDF namespacing of methods
12:13	_ato	can't you just namespace qualify them?
12:13	_ato	or is the idea to try to prevent tying them to any one package so you could have multiple implementations?
12:15	rhickey	_ato: right, namespaces would tie them to a lib, but you usually just want tiny field name + more universal name that might cross libs/apps
12:17	rhickey	rhickey: reify/deftypes do not really have full class scope, only the fields have environment bindings, so this might clarify
12:17	rhickey	er, chouser
12:17	rhickey	^^
12:19	qed	hello ladies and germs -- Anyone know of a good way to do syntax hilighting on clojure code for a website?
12:19	qed	I'm using rails right now -- didn't know if there was anything already out there...
12:20	chouser	rhickey: oh, can you refer to fields as if they were locals in method bodies?
12:21	AWizzArd	funny :)
12:26	_ato	aah right.. it's too late at night.. it's universal field identifiers. I read that as method for some reason.
12:27	AWizzArd	too late in the night? East Russia?
12:27	leafw	qed: I am only aware of lisp javascript syntax highlighters.
12:28	_ato	AWizzArd: Australia, it's 3:30 am
12:28	tomoj	github can highlight clojure right?
12:29	tomoj	so I guess that means pygments can do it?
12:29	tomoj	and pygments has a ruby wrapper
12:29	tomoj	qed: ^
12:30	tomoj	yes, clojure is on pygments' language list
12:31	kefka	,(class (hash-map))
12:31	clojurebot	clojure.lang.PersistentArrayMap
12:32	_ato	kefka: array maps are used as an optimisation for small hash maps
12:32	kefka	I know, but there's a problem.
12:33	kefka	I'm working with transient collections.
12:33	kefka	If you're using assoc!, TransientArrayMap is worthless (at least according to spec)
12:34	kefka	because when there are more than 8 keys, the TransientArrayMap is full; assoc! returns the TransientHashMap, but the old array-map sticks around.
12:34	kefka	,(class (hash-map :a 1))
12:34	clojurebot	clojure.lang.PersistentHashMap
12:34	chouser	once you've used 'assoc!' you shouldn't be touching the old collection anyway
12:35	kefka	chouser: you should be using the one returned, I assume?
12:35	chouser	kefka: right. Otherwise you're guilty of "bashing in place" and lots of things will break.
12:36	chouser	(doseq [...] (assoc! ...)) is bad, for example.
12:36	kefka	Same rule for conj?
12:36	chouser	even with transients you should structure your code as if they were immutable, using the new collections, throwing away the old ones.
12:36	_ato	when doing transients the simple rule is you should be able to remove (transient) (persistent!) and replace assoc! with assoc and the code should still work exactly the same
12:36	_ato	yeah
12:37	kefka	So the purpose of transients is just a performance optimization, then?
12:37	chouser	yes, that's it.
12:37	_ato	yes
12:37	clojurebot	http://clojure.org/transients
12:37	chouser	if you want mutable collections ...which you don't! :-)... Java provides several.
12:38	Chousuke	hmmh
12:39	Chousuke	,`(let [foo# 5] `(test ~'foo#))
12:39	clojurebot	(clojure.core/let [foo__5499__auto__ 5] (clojure.core/seq (clojure.core/concat (clojure.core/list (quote clojure.core/test)) (clojure.core/list (quote foo__5499__auto__)))))
12:40	Chousuke	my sq-macro doesn't handle that properly :(
12:40	kefka	chouser, _ato: Thanks
12:40	Chousuke	,`(let [foo# 5] `(test ~foo#))
12:40	clojurebot	(clojure.core/let [foo__5503__auto__ 5] (clojure.core/seq (clojure.core/concat (clojure.core/list (quote clojure.core/test)) (clojure.core/list foo__5503__auto__))))
12:40	kefka	,(doc assoc!)
12:40	clojurebot	"([coll key val] [coll key val & kvs]); When applied to a transient map, adds mapping of key(s) to val(s). When applied to a transient vector, sets the val at index. Note - index must be <= (count vector). Returns coll."
12:41	Chousuke	hm
12:41	Chousuke	,`(x# `[x#] `[x#])
12:41	clojurebot	(x__5521__auto__ (clojure.core/apply clojure.core/vector (clojure.core/seq (clojure.core/concat (clojure.core/list (quote sandbox/x__5519__auto__))))) (clojure.core/apply clojure.core/vector (clojure.core/seq (clojure.core/concat (clojure.core/list (quote sandbox/x__5520__auto__))))))
12:42	Chousuke	hm :/
12:43	Chousuke	I'm not sure how to implement this
12:43	AWizzArd	what do you want to do?
12:44	Chousuke	make my syntax-quote macro work :P
12:45	Chousuke	it doesn't handle nested syntax-quotes with unquoting quite right.
12:47	Chousuke	,`(x# `[~x#] `[x#])
12:47	clojurebot	(x__5526__auto__ (clojure.core/apply clojure.core/vector (clojure.core/seq (clojure.core/concat (clojure.core/list x__5526__auto__)))) (clojure.core/apply clojure.core/vector (clojure.core/seq (clojure.core/concat (clojure.core/list (quote sandbox/x__5525__auto__))))))
12:48	chouser	only a problem when autogensym is used?
12:48	Chousuke	,`(x# `[~x# `~x#])
12:48	clojurebot	(x__5531__auto__ (clojure.core/apply clojure.core/vector (clojure.core/seq (clojure.core/concat (clojure.core/list x__5531__auto__) (clojure.core/list (quote sandbox/x__5530__auto__))))))
12:49	Chousuke	as far as I can tell.
12:49	Chousuke	but that's just evil now.
12:50	Chousuke	,`(x# `[~x# y# `~y#])
12:50	clojurebot	(x__5536__auto__ (clojure.core/apply clojure.core/vector (clojure.core/seq (clojure.core/concat (clojure.core/list x__5536__auto__) (clojure.core/list (quote sandbox/y__5535__auto__)) (clojure.core/list (quote sandbox/y__5535__auto__))))))
12:51	Chousuke	hmmh.
12:52	Chousuke	,`(x# `[~x# x# `~x#])
12:52	clojurebot	(x__5541__auto__ (clojure.core/apply clojure.core/vector (clojure.core/seq (clojure.core/concat (clojure.core/list x__5541__auto__) (clojure.core/list (quote sandbox/x__5540__auto__)) (clojure.core/list (quote sandbox/x__5540__auto__))))))
12:56	notallama	i was looking at comp, juxt, and partial. why do they have several different arities, rather than just the general "& rest" ones? is it more efficient that way?
12:57	Chousuke	maybe easier.
12:57	Chousuke	because you don't have to manually extract the parameters.
13:01	Chousuke	I think Clojure's syntax-quote is taking advantage of the fact that it's read-time :(
13:01	hiredman	clojurebot: syntax-quote is very hairy
13:01	clojurebot	Ik begrijp
13:05	Chousuke	yeah... the syntax-quotes are actually expanded inside-out, which is why it works.
13:08	Chousuke	hm.
13:09	_ato	Chousuke: I've got no idea how you're implementing it, but can't you make your macro do the same? Perhaps by explicitly macro-expanding everyting inside or something?
13:09	Chousuke	right. that's what my "hm." above was.
13:09	_ato	hehe :)
13:10	rhickey	chouser: yes, fields are in the local environment
13:22	Chousuke	oh wow. it actually works.
13:24	Chousuke	and it succesfully compiled contrib
13:24	rhickey	reify is alive! .methodnames, more docs : http://github.com/richhickey/clojure/commit/9c3e97a85c042d2c3f276f0c1e0d270db35553aa
13:33	dakrone	is there a refactormycode-type site that supports Clojure?
13:38	chouser	quite a week for branch 'new'!
13:38	clojurebot	for is not a loop
13:38	djork	dakrone: that seems like just another pastebin
13:38	djork	I just use gist usually
13:39	drewr	limit on number of case clauses? http://gist.github.com/222567
13:40	dakrone	djork: well, I meant something like "this is my clojure code, please tell me how I can make it better/less java-ish"
13:40	djork	that's what this room is for :)
13:40	djork	I think you'll find most of the programmers online who are able to help you with that right here.
13:41	dakrone	alright then, I'll post it here :)
13:41	chouser	or on the google group
13:41	dakrone	how does this look? http://pastie.org/677017
13:42	dakrone	just kinda looking for feedback as in "don't do this" or "do this instead"
13:42	mikehinchey	rhickey: I like the .methodname change
13:42	mikehinchey	rhickey: I have iterator-seq working with proxy (no java), I'm trying with reify
13:43	chouser	dakrone: if BLIP_SUBMITTED is a field, you don't need parens around it
13:43	chouser	use (inc x) instead of (+ 1 x)
13:43	djork	ah the geek favorite... die rolling
13:44	dakrone	chouser: okay, will do, thanks
13:44	chouser	no need for re-pattern around #""
13:44	chouser	you might consider using destructuring in calculate-rolls
13:46	dakrone	chouser: so something like (let [[text dice sides] txt] ...) ?
13:47	chouser	instead of (if-not (= (re-find ...) nil) foo) you can say (when (re-find ...) foo)
13:48	chouser	dakrone: or just (defn cr [[text dice sides]] ...) not sure if you'll like the results since you'd still have to process dice and sides.
13:48	dakrone	chouser: is it similar to Ruby where anything other than 'false' or 'nil' is true?
13:48	chouser	dakrone: exactly
13:48	dakrone	okay, that helps
13:49	chouser	dakrone: looks good! nice clean code, good use of high-order functions, no state
13:50	dakrone	chouser: thanks! I appreciate the feedback very much
13:51	chouser	dakrone: you have it actually working on wave?
13:52	dakrone	chouser: yep, works great
13:52	chouser	very cool. I just haven't taken the time yet to do anything with wave.
13:52	dakrone	chouser: so far building robots is the best part of Wave :)
14:00	djork	and in clojure, no less
14:03	drewr	where's a current example of deftype?
14:03	drewr	the Datatypes wiki seems out of date
14:04	chouser	drewr: yeah -- by at least 2 or 3 days.
14:04	chouser	you're probably best of looking at the wiki for concepts and the deftype docstring for syntax.
14:04	GenericUser0	Hello
14:04	rhickey	drewr: docstring has gotten a lot better - feedback welcome
14:05	rhickey	now that reify is in, I'll doc all three (reify/deftype/defclass) on the wiki soon
14:05	GenericUser0	What is the idiomatic way of performing a zip of several collections in clojure? I can't seem to find a zip function in the API.
14:06	chouser	GenericUser0: 'map' takes multiple collection args
14:06	rhickey	so you can just map vector
14:07	GenericUser0	Ah, ok. Thanks.
14:08	rhickey	,(map vector [1 2 3] [:a :b :c] [:d :e :f])
14:08	clojurebot	([1 :a :d] [2 :b :e] [3 :c :f])
14:11	froog	what is reify?
14:12	rhickey	froog: like proxy but: faster, limited to interfaces
14:13	rhickey	(seq (reify [clojure.lang.Seqable] (.seq [] (list 1 2 3)))) -> (1 2 3)
14:15	rhickey	the method bodies are true method bodies, yet close over local scope, calls have no lookup and no indirection to fns, much faster construction
14:16	froog	rhickey: great, thanks, I see now
14:20	djork	can I just gush for a second and say how freaking brilliant the lazy-seq facilities of clojure are?
14:20	djork	the fact that take is lazy just blows my mind
14:20	djork	(take 1 (take 10 x)) for example
14:22	djork	not that I'd do that, I just have a function that returns (take n ...) and I just wanted the first one, so I took one and it was faster!
14:23	djork	ok, </fanboyMode>
14:27	Chousuke	arr, recursively macroexpanding syntax-quote breaks :(
14:28	Chousuke	I wonder if I could just cheat and limit the depth... and then hope no-one has `[x# `````[~x#]]
14:28	drewr	so is my case clauses benchmark retarded?
14:28	Chousuke	,`[x# `````[~x#]]
14:28	clojurebot	java.lang.ClassFormatError: Invalid method Code length 66815 in class file sandbox$eval__5550
14:28	Chousuke	:D
14:29	Chousuke	okay, looks like I should be fine.
14:29	drewr	since the dispatch is supposed to be constant-time I thought I'd see for myself
14:29	Chousuke	,`[x# ```[~x#]]
14:29	clojurebot	[x__5554__auto__ (clojure.core/seq (clojure.core/concat (clojure.core/list (quote clojure.core/seq)) (clojure.core/list (clojure.core/seq (clojure.core/concat (clojure.core/list (quote clojure.core/concat)) (clojure.core/list (clojure.core/seq (clojure.core/concat (clojure.core/list (quote clojure.core/list)) (clojure.core/list (clojure.core/seq (clojure.core/concat (clojure.core/list (quote quote)) (clojure.core/list (qu
14:34	twbray	,(re-seq #".*" "foo\nbar\n")
14:34	clojurebot	("foo" "" "bar" "" "")
14:35	chouser	. doesn't match newline
14:35	twbray	Right, but would've expected ("foo" "bar" "")
14:35	twbray	,(re-seq #".*" "foo\nbar")
14:35	clojurebot	("foo" "" "bar" "")
14:37	chouser	* is zero or more
14:37	chouser	,(re-seq #".+" "foo\nbar")
14:37	clojurebot	("foo" "bar")
14:38	twbray	Yeah, but if I'm trying to break "foo\nbar\n" into line fragments, I want 3 fragments, one empty. So .* is really what I want not .+
14:39	chouser	perl does the same
14:40	twbray	Sigh. OK.
14:40	chouser	perl -e'$x="foo\nbar\n"; $x=~s/.*/[$&]/g; print "$x\n"' ==> [foo][]\n[bar][]\n
14:42	chouser	,(re-seq #"(?m)^.*$" "foo\nbar\n\n")
14:42	clojurebot	("foo" "bar" "")
14:42	twbray	Wow, thanks
14:42	technomancy	,(doc line-seq)
14:42	clojurebot	"([rdr]); Returns the lines of text from rdr as a lazy sequence of strings. rdr must implement java.io.BufferedReader."
14:43	twbray	(re-seq #"(?m)^.*$" "foo\nbar\n")
14:43	hiredman	so arrayseqs are apparently mutable...
14:43	twbray	,(re-seq #"(?m)^.*$" "foo\nbar\n\n")
14:43	clojurebot	("foo" "bar" "")
14:43	twbray	,(re-seq #"(?m)^.*$" "foo\nbar\n")
14:43	clojurebot	("foo" "bar")
14:43	chouser	hiredman: yeah, if you still have access to the array
14:44	hiredman	chouser: :(
14:44	chouser	twbray: that's the normal meaning of \n -- as a line terminator not a line separator
14:44	chouser	twbray: at least I assume that's why ^ doesn't match after the last \n
14:45	twbray	Yeah, got a java.nio.CharBuffer I want to split into \n-separated chunks and it really matters if there's a trailing \n because that means an empty chunk
14:46	notallama	you can put flags on patterns in java to change the behavior of /n and such.
14:46	chouser	this is rather surprising:
14:46	chouser	,(seq (.split #"\n" "foo\nbar\n\n\n\n"))
14:46	clojurebot	("foo" "bar")
14:46	twbray	Ah, flags, good idea
14:48	GenericUser0	Why does something like (apply (partial < 5) 6) fail?
14:48	hiredman	apply expects the last arg to be a seq
14:48	chouser	apply require its last arg to be a collection
14:48	GenericUser0	(sorry if I get disconnected, my anti-virus is being annoying today, and seems to want to kill anything associated with IRC...)
14:48	hiredman	,(apply (partial < 5) 6 nil)
14:48	clojurebot	true
14:48	hiredman	,(apply (partial < 5) 6 '())
14:48	clojurebot	true
14:49	hiredman	,(apply (partial < 5) 6 [])
14:49	clojurebot	true
14:49	hiredman	etc
14:49	twbray	Where do regex flags like /s and so on in #"" regexes?
14:50	notallama	twbray: you might have to dip into java to do it, and use the horrible java regex syntax.
14:50	twbray	notallama: Yeah, that may be it
14:50	chouser	,(take-nth 2 (re-seq #".*" "foo\nbar\n"))
14:50	clojurebot	("foo" "bar" "")
14:51	hiredman	java regex flags are generally something like (?i) at the fron of the regex
14:51	chouser	I used the m flag earlier: #"(?m)..."
14:51	hiredman	,(re-find #"(?i)foo" "FOO")
14:51	clojurebot	"FOO"
14:51	chouser	twbray: but anyway, there's your solution take-nth + re-seq
14:51	twbray	Thanks
15:00	krumholt	hi anyone knows a good book about functional software architecture? i want something similar to the hundreds of books about object-oriented analysis and design. just for functional programming
15:00	duncanm	dum de dum
15:01	duncanm	i have this little bit of Java code, I can't quite think of a way to write it in idiomatic clojure - http://gist.github.com/222629
15:01	chouser	I wonder if the various functional languages are similar enough for a general text to be useful.
15:02	duncanm	hey chouser
15:02	duncanm	while ((count = input.read (data, 0, SIZE)) != -1) { output.write (data, 0, count); }
15:03	duncanm	loops like that, i don't know what to do, should I go back to using set!, should i use refs?
15:03	duncanm	oh, maybe loop/recur?
15:04	krumholt	chouser, i mean like a book of fundamentals for application development with functional programing languages
15:04	chouser	loop/recur would work, but it always does.
15:04	chouser	duncanm: but repeatedly would probably work here too
15:07	chouser	duncanm: untested: (let [data (make-array Byte/TYPE data-block-size)] (doseq [c (repeatedly #(.read input data 0 data-block-size)) :while (> c -1)] (.write output data 0 c)))
15:07	chouser	loop/recur might be every bit as good
15:17	yacin	agreed
15:17	yacin	whoops
15:17	yacin	wrong chan
15:30	falkor	I was looking at clojure.contrib.graph and noticed that it is mainly directed graphs only, right? Things like undirected graphs, edges with weights.... not there... Or am I failing to see something?
15:31	tomoj	well you could always just have two edges between each node
15:31	tomoj	I dunno about edge weights.. I'm doing stuff with edge weights on directed graphs now and decided to just start from scratch
15:32	falkor	tomoj: that would be a cycle :( Plus, how to do weigths?
15:32	falkor	I am mainly working with weigthed trees... BTW, I suppose you know of JGraphT and JGraph... you might find it helpful....
15:37	tomoj	falkor: yeah been lookin at JGraph but I don't have my network library workin quite well enough yet to use it
15:38	chouser	rhickey: so if I want the speed of direct field access but don't want AOT or a named class, that still points me to reify?
15:38	falkor	tomoj: suggestion, also check JGraphT, in case you have not done it. You might find it interesting
15:40	tomoj	falkor: thanks
15:40	tomoj	not interested in mutable graphs, though
15:40	tomoj	;)
16:06	rhickey	chouser: no, reify and deftype have the same perf - both give you direct field access within methods, reify gives you no access outside, and deftype gives you :field access outside. Both compile method bodies to true methods etc. It's all the exact same code for reify/deftype/defclass, it's just with defclass you end up with a named class which lets you access the fields direct outside of methods
16:07	chouser	ah... right right.
16:08	rhickey	one thing that is not there is any notion of private helper methods
16:09	chouser	with immutable objects the dangers of visible helper functions are pretty low. I guess can be confusing for users to see them.
16:12	rhickey	right, but external helpers can't have same perf as helper methods, at least for deftypes
16:13	rhickey	the problem with helper methods is making them visible to the compiler's host interop infrastructure, the stub class hack would need more work
16:17	GenericUser0	Is there a program that will let me expand the stages of a function call so I can see where it's failing?
16:18	GenericUser0	I have a lot of somewhat complicated functions that are returning closures, and they are composable... so debugging it is rather challenging at the moment.
16:18	GenericUser0	(I'm doing a sort of pattern-matching over s-expressions)
16:18	GenericUser0	suggestions?
16:20	chouser	GenericUser0: do you mean besides stack traces?
16:20	GenericUser0	Stack traces aren't working very well for me at the moment
16:21	GenericUser0	All I get is something like
16:21	GenericUser0	java.lang.IllegalArgumentException: Wrong number of args passed to: user$lit--7233$fn (NO_SOURCE_FILE:0)
16:21	GenericUser0	I think I've mentioned this before.
16:22	GenericUser0	but I'm not sure what happened to my logs.
16:22	chouser	(.printStackTrace *e)
16:22	chouser	that should give you the full trace. Each line of the trace should name a filename and linenumber.
16:23	GenericUser0	I get nil O_o
16:23	GenericUser0	Maybe I'm catching it wrong hang on a sec
16:24	chouser	well, *e is defined at the plain repl for exceptions that bubble all the way out there
16:25	GenericUser0	Argh. Screw McAfee >.<
16:25	GenericUser0	keeps killing my IRC connection, and automatically resetting the firewall rules
16:26	GenericUser0	Yeah, I just nil.
16:26	chouser	GenericUser0: are you at a plain terminal repl?
16:27	GenericUser0	I'm doing basically: (try <my expression> (catch Exception e (.printStackTrace e)))
16:27	GenericUser0	I'm in Clojure Box's emacs
16:27	chouser	oh. hm. that should work
16:27	chouser	without the try/catch slime is supposed to help you out I think, but I don't do slime
16:28	GenericUser0	Oh... I see it now. It's hidden.
16:28	GenericUser0	...still not especially helpful though, unfortunately :/
16:28	GenericUser0	It's being raised by clojure.lang.Compiler.eval
16:29	durka42	try clojure.stacktrace/print-cause-trace
16:29	dakrone	can someone tell me what I'm doing wrong with this xml parsing? http://pastebin.com/d4b960346
16:30	GenericUser0	In the catch from before, instead of .printStackTrace ?
16:30	durka42	GenericUser0: yes
16:30	durka42	it chains through Exception/getCause or whatever it is called
16:31	durka42	dakrone: what are the symptoms?
16:31	GenericUser0	ClassNotFoundException: clojure.stacktrace
16:31	durka42	meh, isn't that what it's called
16:31	durka42	,(use 'clojure.stacktrace)
16:31	clojurebot	nil
16:31	dakrone	durka42: it returns (), instead of the text inside the fcttext XML element
16:31	durka42	,(print-cause-trace (throw (Exception. "blah")))
16:31	clojurebot	java.lang.Exception: blah
16:32	GenericUser0	I don't seem to have that in clojure box for some reason. Huh.
16:32	durka42	,(print-cause-trace (Exception. "blah"))
16:32	clojurebot	java.lang.Exception: blah at sandbox/eval (NO_SOURCE_FILE:-1) clojure.lang.Compiler.eval (Compiler.java:4623) clojure.core/eval (core.clj:1966) hiredman.sandbox/cond_eval (sandbox.clj:72) hiredman.sandbox/eval_in_box_helper (sandbox.clj:108) hiredman.sandbox$eval_in_box__112$thunk__117.invoke (sandbox.clj:123) hiredman.sandbox/wrap_exceptions (sandbox.clj:32) hiredman.sandbox/wrap_exceptions (sandbox.clj:28) hiredman.sand
16:32	durka42	GenericUser0: if you have an oldish version of clojure, it's clojure.contrib.stacktrace
16:32	GenericUser0	Is it very new?
16:32	chouser	dakrone: :forcastday -> :forecastday ?
16:32	GenericUser0	Ah
16:32	GenericUser0	now it works. Thanks
16:33	dakrone	chouser: totally missed that typo, unfortunately it still only returns ()
16:33	chouser	xml-> turns out to be quite fragile like this. Not sure how to fix it. :-/
16:34	dakrone	chouser: is there a recommended way? searching the internet reveals a number of different methods, but no real exhaustive examples
16:35	chouser	as in alternatives to zip-filter?
16:35	dakrone	chouser: that or the recommended xml-parsing way
16:36	chouser	I dunno. I wrote zip-filter exactly for scenarios like this, but each time I use it spend some amount of time fiddling with filters that just return empty seqs.
16:36	chouser	I used enlive once, but for XML you have to hack around it a bit, and I haven't used it enough to know if it's any less fragile in this way.
16:37	dakrone	so, should I parse it with java libraries instead of in a clojure way?
16:39	chouser	dakrone: try leaving off the initial :forecast
16:40	chouser	(xml-> feed :txt_forecast :forecastday :fcttext text)
16:41	dakrone	chouser: yep, that fixed it
16:44	dakrone_	chouser: how does the (text ...) call know that the content is inside a :content tag?
16:44	chouser	text is c.c.zip-filter.xml/text, specific to the maps produced by c.xml/parse
16:45	dakrone_	oh okay
16:46	dakrone_	makes much more sense now
16:51	chouser	rhickey: when there are collections that support primitives and/or fns with primitive args, with the interfaces support all types but throw runtime errors on incorrect types, or will there be multiple interfaces (presumably with almost nothing in common)
16:51	chouser	rhickey: I ask because I'm thinking about primitive measure/reduce for finger-tree
16:53	rhickey	chouser: don't know yet - certainly they must support the object interfaces for compatibility. There may be parallel interfaces for long/double, or methods next to existing (although not type-overloaded - new type-qualified names, e.g. valAtLong)
16:53	chouser	ok
16:56	chouser	Right now I have [(fn measure ...) (fn reducer ...) init-val]. So I'm thinking those could be methods of a reify with IMonoid
16:56	rhickey	I do know I want to restrict it to long/double at the interface, i.e. that is all that will be supported by fn (eventually).
16:56	chouser	yep, and that makes sense to me.
16:58	chouser	It's hard to see how else to allow primitives for my IMonoid methods without ILongMonoid and IDoubleMonoid, and then not have those either checked at runtime or bubble all the way up to IFingerTreeMeasureLong and IFingerTreeMeasureDouble
16:58	chouser	well, anyway, gotta run. Thanks for your answers.
17:20	kanak	Hi. Can someone tell me whether cons is lazy by default, or if it is lazy only when wrapped around lazy-seq?
17:20	hiredman	lazy-seq
17:21	kanak	thank you.
17:21	kanak	is there a way for me to check if something is a lazy seq?
17:23	digash`	,(instance? clojure.lang.LazySeq (lazy-seq []))
17:23	clojurebot	true
17:24	kanak	thank you digash.
17:27	kanak	Can someone tell me when i should prefer cons to conj (or vice versa)?
17:29	cemerick	kanak: can only "add" to a list (or nil). conj will "add" to any collection.
17:30	rhickey	kanak: conj in almost all cases other than when building a lazy sequence using the general form (cons first-item (recursive-call to build rest))
17:31	kanak	thank you rhickey and cemerick.
17:33	rhickey	kanak: sure
17:40	twbray	I have a big list and I want to map a function onto it, but the function is mostly (send ), no useful result, is there an equivalent of (map that doesn't bother returning the new list?
17:41	kanak	twbray: doseq?
17:41	rhickey	twbray: what map actually returns is lazy (the list doesn't yet exist), you can call dorun on that and it will walk it (for effects), discarding the result
17:41	rhickey	but sometimes that is better expressed with doseq
17:41	twbray	Oh cool. Thanks
17:46	technomancy	it's not an optimization if you use doseq to communicate intention... using map on some level implies you're interested in the return value
18:02	st3fan	hm how do i filter on a map?
18:03	st3fan	filter on a map seems to return a vector instead of a map
18:03	Chousuke	you can treat it as a seq of [k v] vectors
18:03	st3fan	hmm
18:03	st3fan	i basically want to filter out some key/value pairs as part of a swap! operation
18:04	Chousuke	so (into {} (filter (fn [[k v]] ...) amap)
18:04	technomancy	st3fan: you can also reduce conditionally
18:04	technomancy	into is probably clearer though
18:04	st3fan	i'll give it a try
18:06	st3fan	got it!
18:16	rhickey	doc update in progress: https://www.assembla.com/wiki/show/clojure/Datatypes
18:27	kanak	Is the idiomatic way to do letrec (scheme)/lables (cl) in clojure just using a private function using defn- ?
18:31	rhickey	,(doc letfn)
18:31	clojurebot	"([fnspecs & body]); Takes a vector of function specs and a body, and generates a set of bindings of functions to their names. All of the names are available in all of the definitions of the functions, as well as the body. fnspec ==> (fname [params] exprs) or (fname ([params] exprs)+)"
18:32	rhickey	kanak: letfn ^^
18:33	kanak	rhickey, thanks again :)
19:23	kanak	hmm. why does (seq? [1 2 3]) return a false?
19:25	Chousuke	kanak: a vector is not a seq by itself. You need to call seq on it to get a sequence view of it.
19:26	kanak	I see. So how do i test if something is a clojure sequence?
19:26	technomancy	kanak: iseq? tests if it implements the seq interface
19:26	technomancy	or if it can "become" a seq
19:27	Chousuke	there actually is such a function now?
19:27	technomancy	erm; it's called something else
19:27	Chousuke	,(seqable? "foo")
19:27	clojurebot	java.lang.Exception: Unable to resolve symbol: seqable? in this context
19:27	Chousuke	hmm
19:27	Chousuke	something likethat was in contrib
19:27	Chousuke	but nothing in core :/
19:28	technomancy	wouldn't be the first time
19:28	kanak	contrib.core has seqable
19:29	gthompson	does sequential? do it?
19:31	kanak	sequential? gives the desired results but I wonder if using it in this sense is misusing it.
19:41	gthompson	I'm new to clojure so I don't know what the intended use of sequential? is? I just found it with autocomplete in slime ;)
19:48	kanak	gthompson: sequential? checks if the object implements Sequential, whereas I want to test if something implements Seqable (i.e. supports first, rest, and next). So i think like its just a coincidence that it gives the right answer right now :)
19:50	gthompson	a happy coincidence today is the road to a horrible bug tomorrow :)
19:50	kanak	my thoughts exactly :D
20:13	bitbckt	A little word-of-tweet goes a long way.
20:13	terrycojones	bitbckt: :-P
21:37	cemerick	whoa, since when is #clojure dead on a Friday night? :-P
21:38	Knekk	since everyone is attending halloween parties dressed up as Scala and Haskell
21:39	terrycojones	clojure doesn't need a costume to look scary :-)
21:41	_ato	terrycojones: http://dorophone.blogspot.com/2009/05/clojure-style-destructuring-binding-for.html
21:41	_ato	unfortunately elisp is too limited to be able to be morphed completely into clojure via macros :(
21:45	terrycojones	_ato: thanks!
21:45	chouser	terrycojones: it is inevitable that many will try. likely that most will fail.
21:46	chouser	maybe we'll be lucky and one wil succeed.
21:47	terrycojones	chouser: hope so.
21:47	froog	is the problem with mutual recursion by design or implementation?
21:48	chouser	froog: implementation. JVM.
21:48	_ato	froog: you mean the lack of tail call optimization?
21:48	froog	_ato: I mean like: http://en.wikibooks.org/wiki/Clojure_Programming/Concepts#Mutual_Recursion
21:49	froog	that you have to make a forward declaration
21:49	chouser	oh
21:49	chouser	requiring forward declarations is a design choice I believe.
21:50	froog	chouser: pity, its a bit of a wart, I think
21:51	chouser	froog: you're not alone in that opinion. If you check the google group you'll find it's been discussed a bit.
21:55	chouser	I haven't found it to be a problem.
21:57	froog	chouser: its not enough to put me off clojure :)
22:15	cemerick	it seems that someone could make a better emacs using clojure and one of the IDEs out there. Building from scratch seems a little nuts
22:19	steiger	emacs is very big and quite complex, and great. i see no point in re-doing it
22:19	cemerick	I agree on the big and complex part, but lots of people like tilting at that particular windmill.
22:21	froog	It seems that for every language, at least one person thinks emacs should be rewritten in it
22:21	froog	maybe not brainf*ck
22:25	notallama	mit scheme is emacs redone in scheme, isn't it?
22:30	cemerick	It's just a scheme impl AFAIK
22:31	cemerick	notallama: maybe you're thinking of PLT scheme, which has a pretty decent IDE?
22:31	chouser	well there scratch and scratch. Java swing comes with pretty much an entire programmable text editor built right in.
22:32	_ato	well rewriting emacs in clojure wouldn't do it as the whole reason emacs is great is that it has so much code already for it
22:33	_ato	it'd be nice if someone did something that let you write clojure code to drive emacs and interoperate with elisp libraries, like how you can write clojure code that interoperates with java libraries
22:53	notallama	cemerick: i'm thinking of edwin. it comes with mit scheme, and it knows how to eval scheme, but i'm not sure if it's written in it or not.
22:54	cemerick	chouser: yes, the javax.swing.text API is pretty good, as such APIs go
23:06	hiredman	I sent and email about my reader to clojure-dev
23:06	hiredman	and screwed up the quickstart instructions twice
23:06	chouser	hiredman: we won't hold it against you. :-)
23:07	hiredman	:)
23:34	chouser	I just glanced at my email and saw "Kevin ... Reader - I have written a Clo..." and I thought a third person has written a Clojure reader in Clojure!?
23:34	chouser	...before remembering hiredman's real name. :-)
23:34	hiredman	:P
23:35	hiredman	I would love to have a third implementation
23:44	cemerick	hiredman: hah, I had no idea what your name was -- I thought, wow, everyone's got their own clojure reader impl these days. :-)
23:45	cemerick	Of course, chouser just said exactly that. Wow, I'm tired.
23:45	chouser	I haven't talked much about my reader, but it's better than everyone else's. It uses monads.
23:46	chouser	I mean it is a monad.
23:46	froog	night all!
23:49	chouser	http://tinyurl.com/yf76rln
23:51	notallama	maybe i'll write a clojure reader in clojure. by the time i get to it, it won't be third, though.
23:52	ambient	this like a competition or something? write a clojure reader and win a prize? :p
23:52	notallama	reader golf, perhaps