#clojure – 2011-07-18

2011-07-18

00:47	ieure	Can someone explain this seemingly insane MessageDigest behavior? https://gist.github.com/e8cead34d39c2b93fae1
00:47	ieure	I get a different hash value every time I hash the same text.
00:47	ieure	At least, that’s what it looks like.
00:48	brehaut	ieure: are you sure thats not just the address of the byte array?
00:49	ieure	brehaut, No, but I’m not sure how to get any other value out of it, and (.compareTo a b) results in "No matching method found: compareTo for class [B"
00:51	brehaut	ieure: deprecated but you can use ##(String. (.getBytes "abc"))
00:51	lazybot	⇒ "abc"
00:52	ieure	Killed slime. :(
00:52	brehaut	,(dotimes [n 3] (prn (String. (.digest (doto (java.security.MessageDigest/getInstance "MD5") (.update (.getBytes "abc")))))))
00:52	clojurebot	"�P�<�O�֖?}(�r"
00:52	clojurebot	"�P�<�O�֖?}(�r"
00:52	clojurebot	"�P�<�O�֖?}(�r"
00:52	brehaut	haha
00:53	brehaut	yeah the digest isnt a string; probably want to base64 encode it if you want to print it ;)
00:54	ieure	And of course there isn’t a Base64 codec in the stdlib.
00:54	brehaut	indeed
00:54	Blackfoot	sha1 gist for files https://gist.github.com/377964
00:54	brehaut	theres an apache commons one though
00:54	ieure	Yeah, I just wanted to avoid another dependency.
00:55	brehaut	ieure: are you trying to compare digests, or get a string repr of them?
00:55	ieure	brehaut, Both.
00:55	technomancy	it's more common to represent md5 as a hex string rather than base64
00:55	technomancy	fwiw
00:56	technomancy	you might be able to do that with format?
00:56	brehaut	technomancy: oh duh of course.
01:02	ieure	Commons-codec’s DigestUtils is way less hassle.
01:02	ieure	Another dep on the pile, I guess.
01:04	brehaut	ieure: crappy imp (str/join "" (map (comp #(format "%h" %) (partial + 128)) bytes))
01:06	brehaut	ieure: im pretty sure my + 128 is wrong
01:18	Havvy	Hmm, what is the easiest way to remove the added spaces between each parameter sent to (println)?
01:18	amalloy	ieure: fwiw, i recently noticed Vash, who produce pretty images (like gravatar's defaults but much nicer) out of md5s
01:18	amalloy	Havvy: use str
01:18	amalloy	&(println (str "A" "B"))
01:18	lazybot	⇒ AB nil
01:18	brehaut	ieure: better version (str/join (map #(format "%02x" %) b1))
01:19	ieure	brehaut, That’s awesome, thanks.
01:19	ieure	amalloy, Interesting, link?
01:19	brehaut	ieure: no problem. credit goes to timc on the ML
01:19	amalloy	https://github.com/thevash/vash/
01:19	brehaut	ieure: http://groups.google.com/group/clojure/msg/3cba3a68b477b39a
01:19	Havvy	brehaut: But I'm trying to remove the characters that are joined between parameters. While str/join is useful, it's the opposite of what I was looking for. :P
01:19	brehaut	ieure: ive checked the output aginst python hashlib
01:19	Havvy	Oh, for somebody else;
01:19	Havvy	amalloy: Yeah, thanks.
01:20	ieure	brehaut, I only care about internally consistent, but you are a champ.
01:20	brehaut	Havvy: added spaces? println adds newlines
01:20	amalloy	brehaut: you're a champ, but you're just not internally consistent
01:20	amalloy	brehaut: it adds spaces too
01:20	amalloy	&(println 1 2 3)
01:20	lazybot	⇒ 1 2 3 nil
01:20	brehaut	amalloy: oh right
01:21	brehaut	&(str 1 2 3)
01:21	lazybot	⇒ "123"
01:22	brehaut	amalloy: lol re:internal consistency
01:28	Havvy	Is there a way to shutdown just one agent?
01:29	amalloy	Havvy: uhhh, it's not clear what the point of that would be
01:31	Havvy	I'm recreating wolf through Clojure, and don't want to keep the agent holding its state to exist where there is no game going.
01:31	amalloy	so let it get GCed. no big deal
01:32	amalloy	just drop your references to it, and the jvm will pick up after you
01:32	Havvy	"to it" being the agent or the data in the agent?
01:33	amalloy	the agent, i meant, but i suppose either could be right
01:33	Havvy	And how do you drop a reference to an agent?
01:34	amalloy	just...no longer have a reference to it
01:34	ibdknox	lol
01:34	amalloy	stop keeping pointers to it
01:48	Pupeno	Why is there a clojars when there's already a maven?
01:49	amalloy	Pupeno: good luck pushing your half-baked library to maven central
01:50	Pupeno	amalloy: the filter what they accept? I'm honestly asking, I don't know.
01:51	amalloy	Pupeno: i'm pretty sure your product has to be pretty polished to get into maven central
01:51	amalloy	but i haven't tried
01:51	Pupeno	Ok, got it.
02:00	Havvy	amalloy: Thanks;
02:12	technomancy	they also require silly things like domain-name group-ids
02:16	amalloy	technomancy: when you're typing java package names all day at work, being asked to specify just a domain name must feel like a real relief
02:45	Havvy	(I return.) How do I get a record from a vector of records if it has :id equal to "Havvy"?
02:47	kumarshantanu	Havvy: (map (= "Havvy" (:id %)) records-vector)
02:47	kumarshantanu	s/(=/#(=/
02:47	kumarshantanu	member:Havvy: (map #(= "member:Havvy" (:id %)) records-vector)
02:50	amalloy	(filter (comp #{"Havvy"] :id) records)
02:51	kumarshantanu	Havvy: amalloy: amalloy's version is correct - it should be filter instead of map
02:51	Havvy	amalloy: That works (after changing ] to a }).
02:52	Havvy	Gracias;
02:53	Havvy	Oh, a set.
03:06	amalloy	Havvy: clear how that works, then?
03:11	Havvy	Yeah.
03:12	Havvy	(comp) is one of my more favorite functions. But I'm not used to using sets and keywords as executables.
03:12	Havvy	s/executables/callables
03:12	lazybot	<Havvy> (comp) is one of my more favorite functions. But I'm not used to using sets and keywords as callables.
04:57	jeffrey04	erm, i am a bit lost here
04:58	jeffrey04	i want to build an application that uses some machine learning libraries
04:58	jeffrey04	currently looking at weka and mahout
04:58	jeffrey04	if i am to use mahout, where do i start? hadoop? mahout?
05:07	clgv	jeffrey04: are there no project related "getting started" pages or tutorials?
05:08	jeffrey04	yes, there is, trying to read thru them, looks like a lot to pick up before i can use mahout in java
05:09	clgv	maybe they have an irc channel as well then you probably have better success chances over there I guess
05:09	jeffrey04	clgv: i hope so
05:10	clgv	jeffrey04: otherwise try setting some example up step by step
06:08	dbushenko	I have updated my web-framework a bit (former ClojureBlog). It is located here now: https://github.com/dbushenko/Clojure-WebApp
06:08	dbushenko	for now it is easier to reuse it and the exmaple code
06:41	bsteuber	dbushenko: looks interesting
06:41	bsteuber	but I wonder, why do you put the framework source in a webapp subdir instead of just a dependency?
06:51	dbushenko	bsteuber: I'm a bit new to all of this. Good idea, btw! I definitely should split it and make a clojar!
06:52	bsteuber	^^
07:04	lnostdal-laptop	(let [[a b] '(1 2)] (+ a b)) => 3 ;; is very nice, but is the same thing possible with `binding' ..?
07:04	lnostdal-laptop	at the moment i'm getting; "clojure.lang.PersistentVector cannot be cast to clojure.lang.Symbol"
07:28	sritchie	lnostdal-laptop: binding doesn't do destructuring -- it rebinds a current symbol, outside the scope of the function
07:34	lnostdal-laptop	yeah, it'd be trivial to create a binding* macro i guess
08:18	Cozey	Hello. I want to create a deftype which behaves like a map but is backed by a java bean
08:18	Cozey	where field access is passed to setX getX
08:18	Cozey	which interface should i use? IPersistentMap or ITransientMap ?
08:36	fullets	Any suggestion as to why (pmap identity [1]) would be throwing RejectedExecutionException when eval'd in a slime session, but not when eval'd in e.g. lein repl
08:53	bendlas	fullets: that looks like a bug in swank-clojufre
08:53	bendlas	/s/swank-clojufre/swank-clojure/
08:53	bendlas	feel free to open an issue here https://github.com/technomancy/swank-clojure/issues
08:55	fullets	bendlas: looks like i'm a bit out of date, i'll try 1.3.2 first
08:56	bsteuber	fullets: yes, that should be fixed now
08:57	bsteuber	so better update both lein and swank
09:02	bendlas	bsteuber, fullets: Oh, now I know why that sounded familiar. Verified on an outdated version myself. Sorry about that.
09:03	Cozey	how do i set deftypes fields ? assoc? they are mutable - so assoc will return the same object right ?
09:03	stuartsierra	deftype fields are not mutable.
09:04	Cozey	"deftype supports mutable fields, defrecord does not" @ http://clojure.org/datatypes
09:04	bsteuber	not per default, that is
09:05	stuartsierra	You have to add ^{:unsynchronized-mutable true} or ^{:volatile-mutable true} metadata to the fields. Then they can be modified with `set!`
09:06	tomoj	isn't there a warning
09:06	stuartsierra	yes.
09:06	stuartsierra	"Don't do this." :)
09:07	Cozey	here be dragons
09:07	tomoj	ah, right - "They are for experts only - if the semantics and implications of :volatile-mutable or :unsynchronized-mutable are not immediately apparent to you, you should not be using them."
09:07	tomoj	I still have no clue what they do :/
09:07	Cozey	btw : what is the difference between them?
09:07	stuartsierra	Read "Java Concurrency in Practice"
09:08	Cozey	:unsynchronized-mutable means just 'there's no lock here'
09:08	stuartsierra	No!
09:08	stuartsierra	volatile != locking
09:08	Cozey	and volatile-mutable means - some other thread may modify it ?
09:09	stuartsierra	Like I said, read Goetz.
09:09	stuartsierra	The definition of 'volatile' is subtle and complicated.
09:09	tomoj	is there no way to make those fields private?
09:11	tomoj	I mean, so anybody who has a reference to one of these can mutate those fields? sounds scary
09:12	Cozey	ok. i'll check out the book.
09:12	Cozey	one question though: in the 'persistent/transient' context, how are normal java objects treated?
09:12	Cozey	or is this a wrong question ?
09:13	Cozey	or are their methods treated like any other 'side effect' call
09:13	bendlas	Cozey: when using java interop, you're on your own
09:13	TimMc	persistent/transient are guarantees some Clojure objects make
09:13	bendlas	that especially include mutable fields
09:13	Cozey	mhm
09:14	TimMc	,(transient (Object.))
09:14	clojurebot	java.lang.ClassCastException: java.lang.Object cannot be cast to clojure.lang.IEditableCollection
09:14	TimMc	,(persistent! (Object.))
09:14	clojurebot	java.lang.ClassCastException: java.lang.Object cannot be cast to clojure.lang.ITransientCollection
09:14	Cozey	mhm
09:15	Cozey	i wanted to be able to pass a java object to clojure functions, where object's properties would be accessed via getX/setY/isZ methods
09:15	Cozey	i thought that i might create a deftype implementing some of clojure's interfaces
09:16	Cozey	and reference the object in its field
09:16	Cozey	but now i'm a little bit afraid i will get all the persistent/transient semantics wrong
09:16	Cozey	especially that i can't find documentation for those interfaces - what do they promise etc.
09:18	buddywilliams	Good morning
09:19	buddywilliams	I was hoping someone could tell me why I cannot sharp-quote an anonymous function
09:19	buddywilliams	#'(fn [x] (* x 2))
09:19	buddywilliams	but I am allowed to sharp-quote a named fn
09:19	fullets	bendlas, bsteuber: thanks - upgrading to the current versions of lein & swank-clojure did indeed fix the problem
09:19	tomoj	what would you expect that to do?
09:19	stuartsierra	buddywilliams: sharp-quote means "get the Var named …"
09:19	Scriptor	#'(fn foo [x] (* x 2))
09:20	Scriptor	,#'(fn foo [x] (* x 2))
09:20	clojurebot	java.lang.ClassCastException: clojure.lang.PersistentList cannot be cast to clojure.lang.Symbol
09:20	TimMc	I suspect buddywilliams is trying to do something like #'some-fun
09:20	buddywilliams	gotha
09:20	buddywilliams	gotcha*
09:20	buddywilliams	since there is no var named.. it fails
09:20	stuartsierra	yep
09:20	buddywilliams	A friend and I are going through onlisp and converting all the examples to clojure
09:21	buddywilliams	to both read a good book and learn clojure
09:21	Scriptor	buddywilliams: yep, fn just returns the function object while any def form returns a var, which is what sharp-quote uses
09:21	TimMc	Cozey: Those interfaces are not really for user consumption, unless you really want to introduce a new transient/persistent pair, which is probably not really what you want.
09:21	bendlas	#' does indeed work on all vars, not just named fns
09:21	stuartsierra	And #' means something very different in Common Lisp.
09:21	buddywilliams	apparently, this works in common lisp: #’(lambda (x) (* x 2))
09:22	buddywilliams	so from what I am gathering, this is impossible in clojure
09:22	Scriptor	yay for lisp 2's
09:22	TimMc	What does it do in CL?
09:22	bsteuber	Cozey: but you don't need mutable references to hold mutable objects
09:22	Scriptor	buddywilliams: that's because CL is a lisp-2
09:22	buddywilliams	returns #<Interpreted-Function C674CE>
09:22	stuartsierra	Functions and variables have different namespaces in CL. #' means "use the function namespace"
09:22	bsteuber	so even a record might be fine
09:23	buddywilliams	I haven't heard of lisp-2
09:23	Cozey	bsteuber: yes ok, i thought it might be ther right way
09:23	Scriptor	basically, whereas in clojure you can pass an actual function object to another function as a parameter
09:23	Cozey	but apparently it's not
09:23	Cozey	when would one use mutables? for speed?
09:23	bendlas	so a plain (lambda (x) ...) in CL would be an error?
09:23	buddywilliams	gotcha stuart
09:23	buddywilliams	no
09:23	buddywilliams	bendlas
09:24	Scriptor	so if the parameter is called 'a' and it contains a function object, clojure is perfectly happy doing (a arg1 arg2...)
09:24	fullets	bendlas: no; #'(lambda ...) and (lambda ...) are equivalent
09:24	bsteuber	Cozey: yes if you implement somethig very low-level and very performance-critical yourself
09:24	bendlas	I see
09:24	bsteuber	like a new collection type
09:24	buddywilliams	stuart I was reading somewhere that you went through onlisp and converted some of the examples - do you have that posted anywhere?
09:24	fullets	bendlas: 'foo : (quote foo) :: #'foo : (function foo)
09:24	Cozey	mhm ok
09:24	buddywilliams	maybe I could reference it if I get stuck
09:24	stuartsierra	buddywilliams: wasn't me
09:25	buddywilliams	ok, I wasn't sure
09:25	Scriptor	buddywilliams: other stuart, I think
09:25	Scriptor	http://thinkrelevance.com/blog/2008/12/12/on-lisp-clojure.html
09:25	buddywilliams	thanks Scriptor
09:26	buddywilliams	I am very new to Clojure/LISP but I want to say that it is very compelling
09:26	bendlas	fullets: yep, been aware of that. Therefore I found #'(lambda ..) confusing
09:27	fullets	bendlas: I think lambda is just special cased because lambda is special. I remember reading somewhere lambda not requiring #' was a change late in the standardisation process, but I may well be wrong
09:28	fullets	So, incanter has swank-clojure 1.3.0-SNAPSHOT in its :dependencies, and I want to use swank-clojure 1.3.2 that I have in my :dev-dependencies. Is there a way to resolve this in favour of 1.3.2?
09:28	bendlas	fullets: I see, thanks
09:29	stuartsierra	fullets: use an exclusion.
09:29	fullets	stuartsierra: ah, thankyou
09:40	dbushenko	how to access HttpRequest from the Ring web-application?
09:40	dbushenko	and the same for HttpResponse?
09:43	Scriptor	dbushenko: check the docs, requests are passed to the function and responses are returned
09:45	dbushenko	Scriptor: I still don't get it. where is HttpServletResponse in the response map?
09:45	stuartsierra	I don't think Ring exposes those.
09:46	dbushenko	stuartsierra: so it is not possible?
09:46	stuartsierra	Probably not with Ring. But you can use the Servlet API directly from Clojure.
09:46	dbushenko	:-( I wanted to use the JavaSequrity from a Ring-based app
09:47	dbushenko	but I need the httpservletrequest to get the context and the current user
09:51	stuartsierra	Check the source - the servlet object must exist somewhere, perhaps you can get at it.
09:52	joegallo	i don't think it does, sadly
09:52	joegallo	https://github.com/mmcgrana/ring/blob/master/ring-jetty-adapter/src/ring/adapter/jetty.clj#L10
09:52	joegallo	they're there alright (the request and response that it), but i don't think you can get at them easily
09:53	joegallo	that said, you could easily copy&paste your own new ring jetty adapter that stored the request object in a var or something
09:53	dbushenko	shit happens.....(((((
10:00	dbushenko	are there any examples of using wrap-flash ?
10:16	bendlas	when using M-x clojure-jack-in, where does the stdout go?
10:18	bendlas	looking at the source, i suspect it just gets muted
10:18	Fossi	anybody else who always reads that as "stout"?
10:18	bendlas	with (set-process-filter process nil)
10:19	bendlas	Fossi: I'm not a native speaker, so till now: no ;)
10:20	bendlas	technomancy: any comments on that?
10:20	bsteuber	Fossi: normally to the swank-repl
10:20	bsteuber	are you in another thread?
10:20	bendlas	bsteuber: yes, I'm talking about BG threads
10:20	bsteuber	the thing is, out just points to swank in the main thread
10:21	bsteuber	so what you can do
10:21	bendlas	like logging from a jetty, or something
10:21	bsteuber	(alter-var-root #'out (constantly out))
10:21	bsteuber	then it'll be the same in all threads
10:21	bendlas	bsteuber: right, that should do
10:22	bendlas	and it really should be made so by default
10:22	bsteuber	oups it was you, not fossi :)
10:23	bendlas	hm, but still, it won't work for java code, writing directly to System.out
10:23	bendlas	or native libs, printf'ing
10:25	bsteuber	hmm
10:25	bsteuber	so better change System.out?
10:26	bendlas	you thing native code isn't an issue?
10:26	bendlas	s/thing/think
10:26	lazybot	<bendlas> you think native code isn't an issue?
10:27	bsteuber	well no idea
10:27	bsteuber	for me, rebinding out is enough
10:28	bsteuber	but if you have a clean way to redirect everything, why not
10:28	bendlas	we could just redirect it into an emacs buffer
10:29	bendlas	called swank stdout/stderr or smth
10:35	bendlas	actually, stdout goes to the buffer right now
10:35	bendlas	it's just appended on top, which is why i overlooked it till now
10:51	dnolen	this is awesome, https://github.com/frenchy64/Logic-Starter/wiki
10:53	dnolen	ambrose explains in great and entertaining detail the simple type checker for the simply typed lambda calc that I posted a while back.
11:08	vijaykiran	Hi all .. I've a noob question editing clojure in Emacs - how can I wrap the existing code in a new function ? is there a shortcut for it ?
11:10	vijaykiran	nevermind found it: M-x paredit-wrap-round :-)
11:11	kumarshantanu	vijaykiran: Alt+Shift+Left_bracket
11:11	kumarshantanu	after placing the cursor at the beginning of the s-exp
11:12	vijaykiran	kumarshantanu: sweet - thanks !
11:13	kumarshantanu	vijaykiran: another way is to type an empty parens first...any kind of bracket, then press Ctrl+Right_arrow_key
11:13	Scriptor	confusing, brackets can specifically be [] in British English and () and US English
11:13	Scriptor	er, the reverse of that
11:14	kumarshantanu	Scriptor: :-) regular brackets in Lisp are these --- ()
11:15	Hodapp	Scriptor: How is it in British English? In US English the convention seems to be to use the latter for outermost, and [] if you're doing that inside of parentheses.
11:16	joly	US here, and I've always heard "brackets" or "square brackets" for [], "parens" or "parentheses" for (), and "angle brackets" for <>
11:16	Hodapp	Same here.
11:16	vijaykiran	kumarshantanu: Ctrl+Right_arrow doesn't work for me - the mac spaces takes over that shortcut. But the Alt+Shift+LeftBracket will help me.
11:16	Scriptor	Hodapp: I'm going by what's in http://en.wikipedia.org/wiki/Bracket#List_of_types
11:17	Scriptor	but what joly said is how I think of it
11:18	kumarshantanu	vijaykiran: Ctrl+Cmd+Right_arrow is the switch-space keystroke on my Snow Leopard, so Ctrl+Right_arrow works for me
11:18	Hodapp	damn, I don't much like #java.
11:18	joly	Interesting list. I don't think of {} as "curly brackets". I've always heard "braces"
11:18	Hodapp	I get that they get a lot of dumb questions, but I really don't like the sorts of dismissive replies that are common.
11:19	Scriptor	I've had cs teachers say curly brackets, probably because it was easier to remember
11:19	Hodapp	joly: I always hear them as "curly brackets" or "curly braces" mostly because "brackets" or "braces" on their own would always be confused with something else.
11:19	joly	yeah
11:19	vijaykiran	kumarshantanu: I'm using lion - anyway - I'll remap the keyboard :-) thanks for the tip.
12:08	dnolen	sorenmacbeth: my take, https://github.com/swannodette/query-extractor/blob/master/src/query_extractor/core.clj
12:12	sorenmacbeth	dnolen: awesome, I like it. you didn't copy/paste the query-key map, but I still see it referenced (line 24). I assume you meant for it to still exist?
12:13	sorenmacbeth	dnolen: nm, I see what you did.
12:16	sorenmacbeth	dnolen: if you wanna do a pull request, I'll merge it. Otherwise, I'll probably just copy/paste your changes manually ;)
12:17	dnolen	sorenmacbeth: done
12:17	sorenmacbeth	dnolen: cheers and thanks!
12:21	technomancy	holy crap, scala.net attempts to automatically map JDK classes to their .NET equivs. that sounds impossibly shaky.
12:23	Scriptor	technomancy: under which question in the release page does it say that?
12:24	Scriptor	nvm, think I found it
12:26	technomancy	it sounds like they have a lot of wrapper classes the likes of which Clojure explicitly avoids
12:27	Scriptor	such as Scala.IO?
12:27	pjstadig	yes, but Scala is statically typed, so presumably it can compile away wrapper classes when necessary?
12:27	technomancy	ah, hadn't thought of that. possibly.
12:29	pjstadig	but maybe that is the "assume a sufficiently smart compiler" fallacy
12:39	sorenmacbeth	I've got 3 irccloud.com invites. If anyone is interested, shoot me an email to soren {at} dopeness {dot} org
12:39	Scriptor	just asked in #scala, apparently JIT inlining is enough to make it not as bad
12:44	gfrlog	is there any reason that calling (slurp) on the org.mortbay.jetty.HttpParser$Input that is my ring request body would be in inappropriate way of processing it?
12:45	gfrlog	I'm having this strange problem where my json data works from browser/ajax, but fails from curl.
12:45	gfrlog	from curl the content-length header is plainly 23, as reported by curl and the ring request, but slurping the body returns the empty string.
12:47	gfrlog	I'm not sure how to debug this :/
12:57	gfrlog	apparently setting the correct content-type (application/json) makes it work :/
12:57	gfrlog	seems pretty weird to me.
12:58	Scriptor	gfrlog: what content-type were you using before?
12:58	gfrlog	I guess compojure probably eager-reads forms so it can provide it to the routes
12:58	gfrlog	Scriptor: it was the curl default, application/x-www-form-urlencoded
13:18	volton	Hi, I am currently reading The Joy of Clojure and I don't understand this function: https://gist.github.com/1090074
13:18	volton	Why does it return a PersistentVector?
13:19	raek	heh, that looks strange...
13:19	raek	maybe a typo
13:19	volton	I copied it from the book tho and it works
13:21	volton	now I get it, it adds the result of f to a vector
13:21	sorenmacbeth	voltron: it returns a PersistentVector because everything is wrapped in square brackets
13:21	volton	sorenmacbeth: you said it so much better
13:25	volton	,()
13:25	clojurebot	()
13:26	volton	So the main difference between Lists and Vectors is that elements are added to the front of the list and to the back of the vector?
13:27	volton	And the following:
13:27	volton	,('(\a \b \c) 1)
13:27	clojurebot	java.lang.ClassCastException: clojure.lang.PersistentList cannot be cast to clojure.lang.IFn
13:27	volton	,([\a \b \c] 1)
13:27	clojurebot	\b
13:27	amalloy	volton: well, you also don't have to quote vectors, as you demonstrated
13:27	kumarshantanu	volton: ,[\a \b \c]
13:28	amalloy	volton: the fact that lists are not callable is not just an inconvenience, either: nth provides fast random access to vectors, but slow random access to lists
13:30	volton	so Vector ~ ArrayList and List ~ Linked List?
13:30	amalloy	uhhh
13:31	amalloy	kinda? i mean, that's more true than if you reversed the associations, but mutability creates a number of other asymmetries
13:31	raek	volton: basically. they are immutable (and persistent), so there are some other differences
13:31	volton	yes of course I know that but just regarding the runtime complexity of basic operations
13:31	raek	volton: to create a new list with one element in the middle changed, you need to create new nodes for all elements before the middle one
13:32	raek	vectors have more sophisticated random access and update capabilities
13:32	raek	yes. kinda.
13:33	raek	and a clojure list is singly linked, unlike the java LinkedList
13:33	volton	ah, good to know
13:33	amalloy	volton: that kinda falls out of the immutability
13:34	amalloy	having a backlink is fairly pointless if you can't update it, and it would mean that every change to a list requires recreating every entry
13:41	raek	name-this-function time! https://gist.github.com/1090133
13:42	amalloy	raek: imo error-fn should accept [res & args]
13:42	raek	that makes sense.
13:43	amalloy	i'd call it something like attempt
13:43	raek	then should success-fn accept [res & args] too? :-)
13:43	raek	amalloy: good name
13:47	volton	thanks for your help guys!
13:52	cemerick	I'd become the biggest google+ booster ever if it provided a way to vote GGroups threads down into oblivion.
13:54	mayankkohaley	Hello Guys
13:55	mayankkohaley	I want to learn clojure , can somebody please let me know some good books for learning clojure
13:59	dnolen	mayankkohaley: http://www.amazon.com/s/field-keywords=clojure
13:59	dnolen	I have Programming Clojure & Joy of Clojure, both are good.
14:00	mayankkohaley	dnolen thanks a lot
14:02	amalloy	oh dnolen, i see you responded to my tweet-question. mispaste would be weird, because the (run 4) example sxhibits similar behavior
14:04	dnolen	amalloy: so you're running this on your machine? I don't see _.0. clojure 1.2.1 + core.logic 0.6.2 right?
14:04	amalloy	dnolen: no, i'm not
14:04	dnolen	amalloy: both examples are wrong, I've sent ambrose corrections.
14:05	amalloy	dnolen: whew, thanks
14:05	dnolen	amalloy: _.0 is ridiculous, that type can only be a function.
14:05	dnolen	for those cases
14:05	amalloy	right
14:06	dnolen	amalloy: good catch, thx.
14:28	buddywilliams	,(println "hello world")
14:28	clojurebot	hello world
14:28	buddywilliams	very cool
14:33	pmbauer	botsnack
14:34	amalloy	~botsnack ;; pmbauer
14:34	amalloy	hm. apparently clojurebot doesn't like excess args
14:34	clojurebot	forget botsnack is Thanks, but I prefer chocolate
14:35	pmbauer	ah :)
14:35	amalloy	$botsnack ;; or this
14:35	lazybot	amalloy: Thanks! Om nom nom!!
14:35	technomancy	clojurebot: forget forget botsnack \|is\| Thanks, but I prefer chocolate
14:35	clojurebot	I forgot that forget botsnack is Thanks, but I prefer chocolate
14:35	technomancy	geez
14:35	amalloy	hahaha
14:35	technomancy	how did that get in there
14:35	amalloy	technomancy: ISTR someone getting very excited about clojurebot accepting instructions from random strangers
14:36	amalloy	and teaching him a bunch of nonsense
14:36	technomancy	The Internet: it's new to some people.
14:36	technomancy	amalloy: just don't tell him about Wikipedia
14:36	amalloy	haha
14:37	technomancy	though I guess you could always point him to the page about chickens
14:37	technomancy	because dudes already know a lot about chickens
14:37	technomancy	as do ladies, typically
14:37	technomancy	http://www.everytopicintheuniverseexceptchickens.com/
14:39	amalloy	technomancy: fascinating
14:40	amalloy	hah. and the writing style is so distinctive, i almost didn't have to doublecheck that it was ryan
14:40	technomancy	so true
14:40	bulters	you've got to love the sound of memes swooshing by...
14:41	Scriptor	no wonder I kept picturing a T-re
14:41	Scriptor	x
14:44	amalloy	technomancy: and yet that article seems unmolested. does this explain all the vandalism on the rest of wikipedia?
14:47	technomancy	yeah, entirely too tame: http://en.wikipedia.org/w/index.php?title=Chicken&action=historysubmit&diff=418205235&oldid=418205062
14:52	pmbauer	Here we are, Wikipedia chicken vandalism ... all because I couldn't remember the delimiter for botsnack
14:53	pmbauer	;)
14:54	bulters	mankind will remember you
14:54	bulters	they will talk about you when discussing the beginning of the end of Wikipedia
15:33	dans	can anyone help me with setting up vimclojure? cant get the ng console to work: https://gist.github.com/1090423
15:33	dans	i've installed it with leiningen
15:50	markskilbeck	dans: I never even got that far. Had to bite the bullet and use emacs. Mucho simpler.
15:52	dans	i have never used emacs, not really an option
15:54	Somelauw	dans: I have the same problem. Right now I use vim for writing + syntax highlighting + autocompletion and copy pasting to console for testing.
15:54	markskilbeck	Somelauw: sounds long-winded.
15:54	Scriptor	dans: have you looked into slimv?
15:54	Scriptor	might be enough to replace nailgun
15:55	markskilbeck	Actually, it was slimv that I couldn't get installed.
15:55	markskilbeck	I think... My memory isn't cooperating.
15:56	Somelauw	markskilbeck: When using emacs I am always fighting with it. Like if I want to surround a form by another one, I put a ( before it and it creates (). Then I press backspace and it deletes ().
15:56	chouser	I recommend https://bitbucket.org/agriffis/screenrepl
15:56	dans	Somelauw: i think i will do the same, at least the syntaxhighlighting is sort of working
15:57	Scriptor	how do I wrap a sexpr in square brackets with paredit?
15:57	amalloy	Scriptor: M-x paredit-wrap-square
15:57	raek	Somelauw: that's paredit (which can be disabled). just select the thing you want to wrap and then press (, or type the ( and then press C-<right>
15:57	amalloy	bind that to a key if you want
15:57	Scriptor	Somelauw: that's because you have paredit enabled
15:57	amalloy	raek: (or just M-(, which seems easier to me)
15:58	Scriptor	I'm trying to learn it though and it's actually pretty cool, http://www.emacswiki.org/emacs/PareditCheatsheet helps a ton
15:58	Scriptor	amalloy: thanks
15:58	dans	lets face it, vim is so much cooler
15:58	raek	amalloy: oooh, nice!
15:59	amalloy	raek: yeah, i only recently bound M-[ and M-{ to similar things
15:59	Somelauw	I wonder if there are many people that use emacs for lisp languages and vim for everything else.
15:59	markskilbeck	Somelauw: I do.
16:00	amalloy	Somelauw: gfrlog uses emacs just for irc, i think. madman
16:01	Scriptor	Somelauw: that's what I'm using
16:01	Scriptor	*doing
16:02	Scriptor	though if it wasn't for slime being so easy I'd be pure vim
16:02	markskilbeck	Scriptor: ++
16:03	Somelauw	But thanks for helping me with paredit. I will remember it for when I give emacs another go.
16:03	amalloy	paredit is solid gold
16:04	amalloy	once you stop fighting it, anyway. a settling-in period is inevitable
16:04	Somelauw	Okay, I am going to try it right now.
16:06	amalloy	Somelauw: and when you get really desperate or frustrated with paredit, you can always insert a character manually with C-q
16:06	amalloy	but it's super-handy to, eg, just hit ] whenever you want to close any kind of bracket, and let paredit figure out which kind and where it belongs
16:06	ejackson	or, in aquamacs, with an OSX copy paste. sneaky.
16:07	amalloy	ejackson: just an emacs kill/yank works fine too
16:07	dnolen	Somelauw: depends on what languages, Emacs support for functional/logic programming languages seems superior.
16:07	ejackson	ok, wasn't sure.
16:07	amalloy	ejackson: even M-x delete-backward-char is fine; paredit only rebinds the backspace key, not the function it's usually bound to
16:08	ejackson	that's polite !
16:08	Somelauw	dnolen: logic programming languages? Do you mean the set of languages consisting solely of prolog? :P
16:08	ejackson	anyway, copy paste of ) etc is a very handy paredit override
16:09	amalloy	ejackson: blech. it's useful to know, but if you use it often enough for it to be "very handy" i'm concerned
16:09	ejackson	no, its just when you need it, you need it.
16:09	dnolen	Somelauw: there are many Prolog variants, Mozart/Oz, Mercury
16:10	Somelauw	But paredit seems to work well, now that I understand it.
16:10	ejackson	oh yeah, its fantastic.
16:11	amalloy	also probably worth remembering are M-r, M-UP, and C-}
16:12	amalloy	C-} looks like some kind of crazy emoticon
16:20	Scriptor	what's the shortcut for switching to the slime repl? (other than C-x b'ing into it)
16:21	bsteuber	C-c C-z
16:22	Scriptor	ah, thanks!
16:23	amalloy	Scriptor: see also C-c M-p: "set the repl's namespace to this file's namespace"
16:24	Scriptor	dude...
16:24	Scriptor	so I don't have to keep doing use?
16:24	amalloy	well, C-c M-p won't do that, it just issues an (in-ns) call, i think
16:25	amalloy	but C-c C-k compiles/loads the current buffer
16:25	Scriptor	right
16:26	amalloy	in that case you never had to do (use), i think
16:27	Scriptor	hmm, I still did if I have functions in my-project.core and I didn't want to have to prefix every function call in the repl with that
16:28	amalloy	Scriptor: you're missing a feature of clojure's repl, not of slime
16:28	amalloy	&(doc in-ns)
16:28	lazybot	⇒ "([name]); Sets ns to the namespace named by the symbol, creating it if needed."
16:28	amalloy	so you could, eg, in a plain repl: (require 'myproj.core) (in-ns 'myproj.core) (my-unprefixed-fn 1)
16:29	Scriptor	amalloy: right, just saying that having to do (use ...) every time I added a new function got tedious
16:29	pmbauer	dans: I tried vimclojure and had much more success with slimv. Swank, paredit, repl buffer, completion are all built-in
16:29	amalloy	Scriptor: i don't understand. you don't have to do that
16:29	Scriptor	amalloy: ah, didn't realize that, thanks
16:29	Scriptor	(regarding the in-ns code)
16:30	amalloy	technomancy's much-loved shortcut for that is (doto 'myproj.core require in-ns)
16:32	bsteuber	I prefer C-c C-k, C-c M-p, C-c C-z
16:32	bsteuber	maybe I should define a shortcut for the three in a row ^^
16:33	ejackson	i feel so backwards. I just keep (use :reload-all ...) in the command buffer and M-p
16:33	amalloy	bsteuber: yeah, i keep meaning to shortcut some combination of those
16:33	amalloy	probably just the last two
16:33	michaelr524	hello everybody
16:33	amalloy	ejackson: shhh, if you say that aloud nobody will ever respect you again
16:34	ejackson	:p
16:34	bsteuber	amalloy: yeah, last two sounds reasonable
16:35	michaelr524	what's the shortcut in emacs to switch to the slime window at the bottom and then back to the code window at the top?
16:36	icey	So, any truth to the rumor that on Wednesday Rich is going to be announcing Smjalltjalk?
16:36	ejackson	michaelr524: C-x o ?
16:37	Scriptor	icey: I'd figure if there's gonna be anything about a new language it'd be more prolog-y
16:37	Scriptor	maybe finally clj-in-clj?
16:37	michaelr524	ejackson: thanks!!!
16:37	amalloy	Scriptor: i imagine we'd have seen git commits leading up to that
16:37	ejackson	np
16:38	bsteuber	maybe clojure's collection types are mutable now for performance reasons :P
16:38	icey	I think it's interesting that nobody's really sure what's going to be talked about
16:39	ejackson	icey: we call it frijjon.
16:39	technomancy	icey: that's clojure/core for you
16:39	Scriptor	if he started targetting php I'll be pissed
16:40	icey	ejackson: lol
16:40	icey	technomancy: it's very apple-y of them... not that i really mind
16:40	Scriptor	the thing is, both rich and sierra were at the last meetup, are they just really good at keeping secrets?
16:40	icey	technomancy: although, I also don't write tons of libs that would be impacted by language changes
16:42	raek	michaelr524: if you use the emacs starter kit, you can use shift and the arrow keys to switch between buffers
16:43	michaelr524	raek: ah, i'm using the clojure-jack-in stuff from technomancy. just starting with emacs, used vim for years... :)
16:43	bendlas	is there some kind of clojure meeting at wednesday?
16:43	amalloy	bendlas: rich is presenting at the nyc meetup
16:44	pmbauer	amalloy: rich hasn't committed very often to clojure's github this year. My guess is there's development going on that's not public.
16:44	amalloy	pmbauer: good point
16:44	Scriptor	bendlas: yep, in nyc
16:44	Scriptor	but they'll be streaming it live
16:45	bendlas	i see
16:45	pmbauer	http://www.ustream.tv/channel/clojurenyc
16:45	pmbauer	6:45 PM EST
16:50	ejackson	my money is on streams
16:51	Scriptor	would streams offer anything new from lazy-seqs?
16:52	raek	EST = UTC-5 ?
16:52	amalloy	raek: yeah
16:53	technomancy	should beEDT
16:54	islon	this code: (let [cal (as-calendar date)
16:54	islon	year (.get cal Calendar/YEAR)]
16:54	islon	(.isLeapYear cal year))
16:54	islon	gives me: Reflection warning, /home/islon/Dropbox/date-clj/src/date_clj.clj:108 - call to isLeapYear can't be resolved.
16:54	islon	as-calendar is already typehinted
16:54	raek	technomancy: so the 6:45 PM time is in UTC-4 then?
16:55	islon	anyone knows how can I remove the warning?
16:55	raek	02:45 at thursday here, then... :)
16:55	technomancy	raek: I don't know, you should ask hiredman to load clojurebot with joda so you could ask him =)
16:57	sorenmacbeth	islon: have you seen https://github.com/getwoven/clj-time ?
16:58	islon	sorenmacbeth: I don't know how looking at clj-time will solve my type hint removing problem
16:59	islon	*reflection-warning removing
16:59	Raynes	technomancy: fwiw, lazybot has joda on the classpath.
16:59	raek	joda-time (clj-time is a wrapper for it) is a much better date and time library
17:00	Raynes	islon: The answer to any question related to dates and times in Java is 'joda'. Period.
17:00	dabd	does anyone know how can I apply the latex listings patch http://alexott.net/common/clojure/clj-latex.txt to include clojure source code in latex documents?
17:01	islon	Raynes: sorry, but I didn't ask anything about dates, i asked about how to remove a reflection warning
17:03	benreesman	how do i check if a reference points to an instance of a primitive array? i can't remember how to spell that
17:04	pmbauer	islon: what is the type returned from as-calendar? isLeapYear is defined on GregorianCalendar, not Calendar.
17:04	amalloy	&(instance? (class (int-array 0)) 10)
17:04	lazybot	⇒ false
17:04	kjeldahl	Any nrepl client running on Emacs yet, or updates on recommended method of running clojure from emacs?
17:05	kjeldahl	(yeah, I've managed to hack together slime stuff and gotten it working before, but it seems less than ideal..)
17:05	islon	pmbauer: (defn- ^Calendar as-calendar ...
17:06	benreesman	amalloy: cool thanks
17:06	technomancy	did someone find the name sexpbot offensive?
17:06	technomancy	I feel like I may have missed out on some Internet Drama.
17:06	Somelauw	very offensive
17:06	pmbauer	islon: That would be why you are getting the reflection warning. isLeapYear isn't defined on the Calendar interface.
17:06	Somelauw	:P
17:07	amalloy	technomancy: there wasn't much drama
17:07	Raynes	technomancy: No. We're using it in a work-related channel and ninjudd gave me a $50 amazon gift card to rename it so that he wouldn't have to explain to his wife what 'sexpbot' had to do with work.
17:07	Raynes	It was actually a pretty fun day.
17:07	technomancy	hah; classic.
17:08	islon	pmbauer: hmmm... you are right, thank you =) i'll try to cast to GregorianCalendar
17:08	amalloy	i figure we'll rename him every week now to make it harder for hiredman to keep him on /ignore
17:12	fliebel	what, sexpbot is now lazybot?
17:12	Raynes	Yessir.
17:12	fliebel	:)
17:20	michaelr524	is there a trick to use (map) int (->)?
17:20	michaelr524	s/int/in
17:20	lazybot	<michaelr524> is there a trick to use (map) in (->)?
17:20	fliebel	michaelr524: how do you want to use it?
17:20	michaelr524	I want to trim every string in a list
17:21	fliebel	michaelr524: So what do you need -> for?
17:22	michaelr524	I already use ->
17:23	fliebel	you can do (-> some code (->> (map fn)) other code
17:23	michaelr524	ahh
17:23	michaelr524	good idea
17:23	michaelr524	let me try that
17:23	michaelr524	:)
17:25	michaelr524	worx!!
17:25	michaelr524	thanks
17:25	michaelr524	fliebel
17:26	bsteuber	michaelr524: but -> inside ->> won't work
17:26	bsteuber	which makes sense when you think about it
17:26	fliebel	Dos anyone have a neat trick for going the other way around? like (->> seq map filter reduce (<<- (nth 4))
17:26	michaelr524	btw, anyone knows why C-C C-C compiling a function is really quick buy C-C C-K compiling the whole buffer takes like 30-40 seconds here?
17:27	amalloy	fliebel: anonymous functions
17:27	amalloy	&(->> (range) (filter even?) (take 10) (#(nth % 4)))
17:27	lazybot	⇒ 8
17:27	stuartsierra	michaelr524I think It's a bug in Emacs on some windowing systems (e.g. OSX) - it takes too long to draw the progress bar.
17:28	amalloy	michaelr524: try (setq font-lock-verbose nil)
17:28	michaelr524	stuartsierra: i'm on xp, here I don't get a progress bar even :)
17:28	fliebel	amalloy: hm, yea, that might work.
17:28	stuartsierra	michaelr524: dunno then
17:29	michaelr524	amalloy: what's that supposed to do?
17:30	fliebel	michaelr524: the reverse of what I showed you.
17:30	michaelr524	fliebel: yeah. I was asking regarding the elisp snippet :)
17:33	michaelr524	amalloy: didn't help, took 38 seconds
17:33	amalloy	michaelr524: the part that's slow is usually emacs running a bazillion regexps on the compiler output, or something crazy like that
17:33	michaelr524	amalloy: yeah, who knows... it might be calling home to andromeda or something :)
17:35	bendlas	michaelr524: in that case you should contact NASA, cause 38 seconds would be wicked fast for that
17:35	bendlas	;)
17:35	michaelr524	didn't they close nasa already?
17:41	bsteuber	damn, I was just writing a cool "-> inside ->>" macro for fliebel and now he left
17:41	bsteuber	but for the fun
17:41	bsteuber	(defmacro ->* [& args] `(-> ~(last args) ~@(butlast args)))
17:43	bendlas	heh, one of our bots should keep a mailbox for offline users
17:43	bsteuber	good idea
17:47	amalloy	bendlas: lazybot already does
17:47	amalloy	$mail bendlas hey a message for you
17:47	lazybot	Message saved.
17:47	bsteuber	cool
17:47	clojurebot	Pardon?
17:48	amalloy	then next time you join/talk, he /msgs you
17:48	bendlas	wut?
17:48	Raynes	amalloy: He sends a NOTICE, I believe.
17:48	bendlas	ok, it didnt message me
17:48	bendlas	brb
17:49	Raynes	Some people have weird settings and don't NOTICE the NOTICEs.
17:49	amalloy	Raynes: yeah, but i don't really understand notices
17:49	bendlas	ok, i didn't get anything
17:49	amalloy	i think it may be a default erc setting. the last guy who had trouble was using erc too
17:49	bendlas	would ERC notify me in a fairly std config?
17:49	amalloy	shrug
17:50	raek	when reading the RFC, you get the impression that notices would be ideal for bot utterances
17:50	Raynes	amalloy: It definitely has to be notices though. PMs would get really annoying really fast.
17:50	Raynes	bendlas: In any case, you can /msg lazybot $mail to get the message.
17:50	raek	but for some reason clients seem to interpret notices as announcements
17:50	raek	and trigger the bell, etc
17:50	bendlas	i see
17:50	bendlas	it worked
17:50	Raynes	raek: Or ignore them altogether. Which is what ERC seems to be doing.
17:51	bendlas	Raynes: no, i just saw it
17:51	Raynes	Oh.
17:51	Raynes	Cool.
17:51	bendlas	but it is fairly well camouflaged
17:51	bendlas	in the irc.freenode buffer
18:17	miltondsilva	~30 min to live feed right?
18:17	clojurebot	The Clojury says to stop making puns.
18:20	icey	miltondsilva: are you asking about the ClojureNYC meetup?
18:20	miltondsilva	ohh... forget it, I see I got the wrong date ;)
18:20	icey	miltondsilva: :)
18:25	bendlas	I have written a dir macro: http://paste.lisp.org/display/123338
18:25	bendlas	feedback very welcome!
18:30	bsteuber	bendlas: why does it need to be a macro?
18:30	bendlas	pure convenience
18:30	raek	miltondsilva: hrm. that time seems 2 hours off to me... are my calculations wrong?
18:30	bendlas	it's for repl use
18:30	bendlas	so you can write (dir clojure.java.io)
18:30	amalloy	bendlas: (if (= `ns dir) ns ...) is madness
18:32	raek	...or one hour, I think
18:32	amalloy	raek: the meetup starts 48 hours and 15 minutes from now
18:32	bendlas	amalloy: let me think for a moment, what that was the workaround for
18:32	amalloy	bendlas: it was for you quoting ns incorrectly in the other clause
18:33	miltondsilva	raek: hmm... I got the wrong day... about the time, according to this http://24timezones.com/world_directory/current_new_york_time.php and this http://www.google.com/url?sa=D&q=http://www.meetup.com/Clojure-NYC/events/16166953/ I think I'm right.. or am I missing something?
18:33	raek	amalloy: eh. my calculations were wrong...
18:33	raek	miltondsilva: no, you were right! (modulo the day)
18:34	raek	00:45 is way more convenient than 02:45 for me... :-)
18:34	amalloy	it's starting to seem like i should give lazybot a $meetup command that says how long till the dang thing starts
18:34	bendlas	amalloy: hm, could you help me make a version that wouldn't need it?
18:34	miltondsilva	I was so excited when I heard there was going to be a live feed that I didn't even confirm the date ;)
18:34	amalloy	the no-arg version should read ([] `(dir ~ns ns-publics)) if you want to do it that way
18:34	Raynes	Where would I create an issue for tools.cli?
18:35	amalloy	since that's basically equivalent
18:35	bendlas	go ahead, try it that way
18:35	Raynes	Only like 3 new contrib projects are even listed on Jira.
18:35	Raynes	tools.cli doesn't seem to have a way to collect extra, unused arguments, which seems like a massive black hole of a missing feature.
18:36	patchwork	Hey #clojure, I have a question on stackoverflow for you guys:
18:36	patchwork	http://stackoverflow.com/questions/6739962/clojure-how-do-i-refer-to-functions-from-a-loaded-file
18:37	patchwork	Thought it would be better to put it there rather than try to type it all out in here, though if that is not kosher let me know
18:38	bendlas	amalloy: ok, got it
18:38	bendlas	first clause needs to read ~(ns-name ns)
18:54	Bronsa	n
18:59	bendlas	amalloy, everybody else: I've slightly rewritte the dir macro, care to have a look again? http://paste.lisp.org/+2N62/1
19:02	amalloy	dorun..map println? i much prefer a doseq
19:04	bendlas	I normally do too, but it saved a gensym that way ;)
19:07	bendlas	anyway, if there is no heaver criticism, I'll propose it for inclusion
19:11	amalloy	inclusion in what?
19:11	bendlas	clojure.repl
19:11	bendlas	instead or maybe in addition to the current clojure.repl/dir
19:12	bendlas	oh, in that case I should also sort it, like the current one does
19:20	methods	what does this mean ? "Clojure multimethods go further still to allow the dispatch value to be the result of an arbitrary function of the arguments."
19:21	brehaut	methods: in the typical OO programs, the dispatch function for all methods is (fn [& args] (class (first args)))
19:21	amalloy	methods: instead of eg java's inheritance-based polymorphism, you can dispatch based on, say, the first three characters of the string
19:21	brehaut	methods: with multimethods you can write whatever function of the arguments you wish
19:22	amalloy	define a handler for "get" and a handler for "set", and then later some user of your lib can add a handler for "put" and they all work together an play nice
19:22	methods	yea but I think the page was implying that it goes a step farther then generic functions ?
19:23	methods	"CLOS generic functions extend dispatch value to a composite of the type or value of multiple arguments, and are thus multimethods. Clojure multimethods go further still ... " ^^
19:23	amalloy	methods: aha. that's dispatch on the value of some argument
19:24	methods	so what your saying is that, "an arbitrary function of the arguments" allows you to do something like test the first 3 letters of a string or something ?
19:24	amalloy	yes
19:24	amalloy	bendlas: i'm aware that this is not very helpful, but i don't like your function and i'm not sure why
19:24	methods	is there an example ? i would to see how it fits in
19:25	brehaut	methods: (defmulti fac identity) (defmethod fac 1 [_] 1) (defmethod fac :default [n] (* n (fac (dec n))))
19:25	amalloy	one thing you can fix at least is (if-let [line1 line2] (-?> ...))
19:25	Raynes	It's difficult explaining abstract concepts.
19:25	brehaut	admittedly thats a terrible example
19:26	Raynes	I'm so happy I don't have to do i... Oh, man, I'm writing a book, aren't I?
19:26	methods	http://clojure.org/runtime_polymorphism
19:26	methods	well i guess that page already shows an example
19:26	amalloy	oh yeah Raynes, how's that book coming?
19:26	amalloy	methods: i've used `count` as a dispatch function
19:26	Raynes	amalloy: Slowly.
19:26	methods	I assume that normally [] is just a type of array or something so by him doing actual matching on the values in the array then he's doing just that
19:27	Raynes	amalloy: My publisher is going to hate me if I don't get to work. And hard.
19:27	brehaut	methods: empty vector
19:27	brehaut	,(type [])
19:27	clojurebot	clojure.lang.PersistentVector
19:27	methods	sorry I'm really new just reading up on it
19:27	brehaut	thats fine
19:28	methods	yea but my point though is that in clos generic functions would you be able to do the same thing or would it simply only be able to dispatch based on fact that you passed a vector ?
19:28	brehaut	i dont know enough about CLOS to answer that
19:29	methods	someone tried to explain to me once the whole solution that generic functions provide .. something about visitor pattern ... but I'm still not sure if I fully get it
19:29	bendlas	amalloy: it's ok, maybe the wider community will flame it with better arguments ;)
19:29	brehaut	visitor pattern is a clunky implementation of double dispatch to implement a generic fold
19:30	brehaut	the visitor calls the visitable thing which calls back to the visitor; it allows single dispatch (based on class) used twice to select the correct implementation
19:30	amalloy	jesus, brehaut, really? that's terrible
19:30	brehaut	yeah really
19:31	amalloy	that class was a really long time ago for me, apparently
19:31	amalloy	$google visitor pattern
19:31	lazybot	[Visitor pattern - Wikipedia, the free encyclopedia] http://en.wikipedia.org/wiki/Visitor_pattern
19:31	brehaut	multiple dispatch functions choose their polymorphic implementation based on the types of al lthe arguments
19:31	brehaut	multimethods choose their polymorphic implementation on any function of the arguments
19:32	brehaut	if CLOS uses multiple dispatch on type alone then multimethods are more versitle
19:32	brehaut	if CLOS lets you define any ufnction of the arguments to dispatch then it is equivalent
19:32	methods	oh wait i see .. i was wondering why there was any code in the defmulti part.. that's where he looks into the values passed in and figures out which method to call..
19:33	brehaut	methods: isa? is used under the hood to do the tests
19:34	amalloy	methods: for example, i have a multimethod here (closed-source, sorry) that takes a map as input. to dispatch, it pulls out one of the keys from the map, does some juggling to convert it into a namespace, and then returns as its dispatch value a keyword with that namespace
19:35	brehaut	oh duh. necesssary evil uses multis to process XML
19:36	brehaut	methods: https://github.com/brehaut/necessary-evil/blob/master/src/necessary_evil/value.clj#L83-101
19:37	brehaut	apparently xmlrpc is more repelant than i realised
19:39	amalloy	brehaut: xml is like the poster child for defmulti
19:39	brehaut	amalloy: it really is
19:39	amalloy	somewhere in cake there's a defmulti i wrote for generating pom.xml, but curiously i can't find it anymore
19:40	amalloy	i wonder if they threw it out
19:40	brehaut	raynes has refactored again hasnt he
19:40	Raynes	amalloy: Really?
19:41	brehaut	Raynes: that was me ruining your good name, not amalloy
19:41	amalloy	Raynes: well, i don't remember where i put it. but a recursive grep turns up only three defmultis, none of which are mine
19:41	Raynes	amalloy: It's in depot.pom now.
19:41	amalloy	ah. depot. i forgot about that nonsense
19:42	Raynes	Watch your mouth. Justin will tase you.
19:42	amalloy	methods: https://github.com/flatland/depot/blob/master/src/depot/pom.clj is another example
19:45	methods	is there anything good to read to understand why multi's are better than oo approaches ? (not trying to flame here) .. like you can obviously have the debate about just writing a big switch statement or creating your own defmulti
19:45	methods	in another language.. but i remember someone arguing with me that it's still not the same ?
19:46	brehaut	methods: theres no reason OO canth ave multiple dispatch over arbitrary functions
19:46	methods	yea but people in #lisp might try to kill you if you say that
19:46	brehaut	methods: the main reason to choose between single dispatch and multiple dispatch is performance
19:47	brehaut	methods: those people are idiots then
19:47	methods	yea because it's like c++'s name mangling
19:47	methods	it's just directly linked right ?
19:47	brehaut	a virtual method in C++ codes is a pointer indirection through the classes vtable
19:48	methods	yea
19:49	brehaut	methods: however, the realm of runtime optimsation and call site caching is deep voodoo for someone like me, so potentially a multiple dispatch scheme might end up no slower than single disptch
19:50	methods	yea i mean in ruby circles people like the duck typing approaching and they don't care really for using obj.type? .. so clojure allowing you to write your own dispatcher seems like it would be more flexible in that approach
19:50	methods	s/approaching/approach
19:50	lazybot	<methods> yea i mean in ruby circles people like the duck typing approach and they don't care really for using obj.type? .. so clojure allowing you to write your own dispatcher seems like it would be more flexible in that approach
19:51	brehaut	im not sure how duck typing has anything to do with multiple dispatch
19:51	methods	well like you said normally it's based on the "type" of the argument right ? but here you can basically write your own dispatcher to test if the object looks like something instead of actually being something
19:51	brehaut	re:just using a big switch statement: if the dispatching logic doesnt need to be externally extensible (in particular run time extensible) then a switch statement may well be smarter
19:52	methods	hm what do you mean by run time extensible ?
19:53	brehaut	code loaded after the multi is defined can extend the multimethod to handle morecases
19:53	brehaut	a switch statement (cond family for example) cannot
19:53	brehaut	its simple late binding
19:53	brehaut	the java equivalent is classes implementing an interface are loaded
19:54	amalloy	methods: see eg clojure.core/print-dup, which is a multimethod in core for readably-printing objects. you can add your own implementation any time, which wouldn't work with switch/case/cond
19:54	brehaut	amalloy: thanks :)
19:55	amalloy	that one only dispatches on type, so it could be a simple protocol, but it demonstrates runtime-extensibility
19:56	brehaut	methods: there a couple of axis here: #{do you need late binding, dont need late binding), #{single dispatch, multiple dispatch}, #{dispatch on type, dispatch on value} and one case not available in clojure: dispatch on return type.
19:59	brehaut	methods: multimethods are late bound, multiple dispatch on value. switch statements are early bound dispatch on value. protocols (and interfaces) are late bound single dispatch on type.
20:00	brehaut	methods: each choice has a tradeoff, but generally the later and less restricted your dispatch mechamism the more powerful it is
20:04	amalloy	(defmulti super-powerful [& args] (JOptionPane/showInputDialog nil (apply str "What should I do with " args))
20:04	brehaut	haha awesome :)
20:08	mudge	anyone know what let* means?
20:09	amalloy	mudge: in a clojure context? it's just a more limited version of let, which let (a macro) uses internally
20:09	mudge	yes, in clojure, ah, is let* a function that let uses?
20:10	amalloy	it's not a function, it's a compiler built-in
20:12	mudge	hmm, i didn't see it on clojures list of primitives
20:15	methods	brehaut: well unless your dispatch method has a register hook or something..
20:16	brehaut	methods: i have no idea what you mean
20:16	methods	amalloy: yea that print-dup reminds me of how they do it in haskell ?
20:17	methods	brehaut: hm on return type ?? wouldn't that just be passing the return value to another defmulti ?
20:17	brehaut	methods: read in haskell is an example of a function that switches on return type
20:17	brehaut	read :: String -> a
20:18	brehaut	if you do (for example) 1 + (read "1") the result is 2
20:18	brehaut	if you do say 'if read "True" then 1 else 2' then it returns 1
20:18	brehaut	because read chooses an implementation based on what the inference engine determines is needed
20:19	methods	I'm confused on how 'read' is doing any switching ?
20:19	amalloy	methods: because it knows what context the result will be used in (it needs an int), it can use the int-making version of read
20:19	brehaut	methods: in the first instance its being used as the second argument to +; the first argument to + is an Integer, so reads return type needs to be an integer, thus read uses that implementation to parse the string.
20:19	brehaut	methods: in the second it needs a Bool
20:19	methods	oh awesome
20:20	methods	hm reminds me of perl's ability to automatically call scalar() on an array in the right context ?
20:21	brehaut	read's return type is determined at compile time not run time
20:21	technomancy	does it blow anyone else away that there's an alternate JVM out there that's 50kloc and still able to run Clojure?
20:21	methods	yea i think a good example would of been 1+(read "1") == 2 vs "1"+(read "1") == "11"
20:21	technomancy	I mean, one that nobody's ever heard of
20:21	brehaut	technomancy: wow. link?
20:21	technomancy	http://oss.readytalk.com/avian/index.html
20:21	brehaut	methods: thats invalid haskell
20:22	methods	technomancy: 50kloc ?
20:22	technomancy	it's missing a certain JMX class that breaks with one feature of Leiningen, but I was planning on nixing that feature anyway
20:22	brehaut	technomancy: thanks
20:22	methods	loc = lines of code ?
20:22	technomancy	methods: 50,000 lines of code
20:22	technomancy	give or take
20:22	methods	hm it's going after the embedded market ?
20:22	technomancy	I guess
20:23	brehaut	lazybot: $heval (read "1")::Integer
20:23	methods	what's wrong with hotspot ? doesn't it have massive jit optimizations...
20:23	technomancy	it can perform native-code AOT that cuts launch time in half, though overall it's still a fair bit slower.
20:23	technomancy	hotspot is like a bazillion kLOC
20:23	technomancy	and hotspot can't AOT to native code
20:24	methods	yea i really wish it supported warm up profiles for the jit runtime
20:24	brehaut	still potentially useful for desktop apps
20:24	technomancy	avian can take clojure 1.2 boot time down to 0.3s; I'd imagine it could do even better with 1.3 since they were planning on loading less at boot for android
20:25	technomancy	anyway, I'm just surprised because it basically came out of nowhere
20:25	brehaut	technomancy: what is your 1.2 boot time? (for a relative comparisons)
20:25	methods	is there any plans to support dispatch on return type ?
20:25	technomancy	brehaut: on the machine he was using it was 0.6s with client hotspot iirc
20:26	brehaut	oh sure
20:26	brehaut	methods: the JVM does not provide a facility to do that
20:26	brehaut	methods: and its only infrequently useful compared to other dispatch models
20:27	methods	yea it just allows you to not need to type the extra code at times
20:27	brehaut	perhaps if dnolen's core.logic and associated type engine plays out well it might get added?
20:27	methods	why would the jvm not support it ? like haskell it could be compile time ?
20:27	bendlas	wow, avian is free software
20:27	brehaut	because the JVM doesnt support a lot of things that are useful for non-java languages? haskell suppots TCO at compile time, but the JVM doesnt
20:27	bendlas	how nice, thanks for the tip, technomancy
20:27	methods	what about llvm's java front end ?
20:28	methods	^ I mean in comparrison to avian
20:28	brehaut	methods: additional inference engines are hard to get working nicely in the presence of subtyping
20:28	methods	what do you mean by tco ?
20:28	brehaut	tail call optimisation
20:29	methods	yea that's what i figured but wasn't sure
20:29	methods	but why would tco be related to return type inference ?
20:29	brehaut	its not; its just an example of something that haskell has that would be nice but because the jvm doesnt have it, we dont have it
20:29	methods	yea i mean it's the same problem that language that compile directly to c have when they want to support tco right ?
20:29	brehaut	(simulating it muddies interop)
20:30	brehaut	thats a can of worms
20:30	brehaut	GCC supports TCO for instance
20:30	methods	ah it has special stuff for it ?
20:30	brehaut	it just plain does it with the right flags
20:30	technomancy	it's funny that avian claims to be "a lightweight alternative to Java"
20:30	technomancy	rather than an alternative to hotspot
20:32	methods	there was this dialect of c i saw once that was made for all these reasons and made for compilers to output to
20:32	brehaut	GHC for a long time targeted C-- as its output language
20:33	brehaut	JVM bytecodes are much higher level than C however
20:33	brehaut	they have classes baked right in for instance
20:33	methods	as far as i know ghc still does the llvm backend or whatever isn't as fast yet
20:34	brehaut	GHC has a number of backends, it uses its own native code one by default though i believe
20:34	mneedham	hey - trying to understand how to dynamically create a symbol - I then wanted to write an assertion that it worked and I thought this one would be ok -> (is (= (symbol ":foo") :foo)) - but it isn't - must be missing something?!
20:34	methods	yea i mean but still your runtime could support some more advanced features on top of the bytecode right ? or is hte main goal to not have anything like that for speed ?
20:34	brehaut	mneedham: :foo is a keyword
20:35	brehaut	,(type (symbol "foo"))
20:35	clojurebot	clojure.lang.Symbol
20:35	mneedham	oh so I want to create a keyword instead?
20:35	brehaut	,(= (keyword "foo") :foo)
20:35	clojurebot	true
20:35	brehaut	correct
20:35	mneedham	ah!
20:35	mneedham	so anything beginning with a : is a keywrod
20:35	mneedham	is that right?
20:35	brehaut	correct
20:35	brehaut	::foo is a namespaced keyword
20:35	brehaut	,::foo
20:35	clojurebot	:sandbox/foo
20:36	brehaut	,(keyword "mymythicalns" "foo")
20:36	clojurebot	:mymythicalns/foo
20:36	mneedham	ah
20:36	mneedham	didn't know you could do that
20:37	bendlas	what's the correct way to propose a feature with a done implementation, for inclusion in clojure?
20:37	bendlas	ticket + pull request?
20:37	brehaut	mneedham: if you are defining heirarchies or similar you definately should namespace your keywords
20:37	bendlas	ticket with attached patch?
20:38	brehaut	bendlas: sign the contributers agreement, post your intentions on the mailing list and then an issue on dev.clojure.org might be created
20:38	brehaut	bendlas: clojure core is conservative on what it accepts and contrib is in a reshuffling phase, and not accepting many (any?)new libs at present
20:39	bendlas	i know, but it's just an improved version of clojure.repl/dir
20:39	bendlas	thanks
20:40	brehaut	bendlas: start with http://clojure.org/contributing if you javem't seen it
20:41	bendlas	I have, just not signed yet, due to inconvenience of faxing
20:41	brehaut	bendlas: international mail agrees
20:41	technomancy	clojurebot: fax machine is http://achewood.com/index.php?date=11222006
20:41	clojurebot	In Ordnung
20:42	brehaut	technomancy: win
20:42	bendlas	analogous mail? oh boy ...
20:43	technomancy	brehaut: my super power is to be able to recall relevant web comics for any given situation.
20:43	brehaut	arrows!
20:43	technomancy	it's up there with Mr. Furious and the Shoveller
20:43	brehaut	hehe :)
20:43	bendlas	:D @ comic
20:45	brehaut	what the hell is wrong with twitter today
20:46	tomoj	they're running clojure now? :D
20:47	tomoj	(nah, not for the frontend, and the stuff that is clojure is workin great I bet..)
20:47	brehaut	heh
20:47	tomoj	wonder if they even have any
20:48	stuartsierra	I think they use Scala a bit.
20:48	brehaut	they have backtype?
20:49	brehaut	i read an infoq thing or similar that claimed theyve got quite a bit of scala now
20:49	tomoj	but I wonder how long it would take for backtype code or its progeny to start affecting twitter.com
20:49	brehaut	i recon it will start effecting their bottom line
20:50	brehaut	i found it to be way better analytics than google analytics for my site
20:54	brehaut	the failwhale was better when it didnt occur inside requests for json
20:57	tomoj	what is it, ascii art, or they give you html back, or..?
20:58	brehaut	i can only see the html if i look in the webkit inspector; the page is empty
20:59	methods	yea i would think this is basically defmulti for ruby ? https://gist.github.com/d78805b13870b6570a9c
21:01	brehaut	not quite
21:01	brehaut	theres only one dispatch function for a multi (put that in your initializer), and then the add_dispatch method takes a value for match not a fn
21:02	methods	well my matcher can do anything it wants to test the passed in values and then if it returns true then i call the given body of code... actually that would call every single method that matches .. and each method has it's own
21:02	methods	tester.. instead of just 1 tester that produces the args to test against
21:02	brehaut	thats more general than a multimethod
21:02	brehaut	and slower again
21:02	methods	wow that was messy way to say that.. let me try again.. instead of 1 test function that produces the arguments used for dispatching
21:03	brehaut	dispatch is now O(n)
21:03	methods	hm and it's not O(n) before ?
21:03	brehaut	whereas multimethods could be much faster O(log n) ?
21:03	methods	well yea i mean O(n) because you have n matchers
21:03	brehaut	exactly. you have to test each matcher function until one matches
21:03	methods	i can make it work more like clojure's approach
21:03	brehaut	of course
21:03	methods	yea but what if you wanted that ?
21:04	methods	$ ./test.rb
21:04	methods	I heard quack
21:04	methods	:]
21:04	brehaut	most people would call that a 'rules engine' or something
21:04	brehaut	and you run into clause ordering problems
21:05	methods	hm
21:05	methods	well yea in this case you just run them all
21:05	brehaut	eg, if i added class BlueDuck < Duck; def quack; "blue quack"; end; end;
21:05	methods	what happens if you define a multi method that has the same arguments of something already defined ? does it over ride it ?
21:05	brehaut	i think i screwed that up
21:06	brehaut	i believe so
21:06	methods	well adding a class would'nt matter i think what you mean is you added another tester function you run in the problem of which one do you hit first ? and since it's a hash it's not even ordered.. then again ruby 1.9 has ordered
21:06	methods	hash's
21:06	brehaut	theres still some ordering on multis i think, but its less significant than having full logic for each test
21:06	brehaut	yeah thats what i meant
21:06	methods	yea but you still run into ordering problems in clojure too right ?
21:07	brehaut	its less of an issue when you are testing values
21:07	brehaut	with comparison
21:08	methods	hm but why ? i mean it's just based on the order y ou define your matchers
21:10	methods	well that example is what i meant earlier when i said instead of using a switch statement
21:10	brehaut	becuse there is exactly one transformation between arguments and dispatch value. each dispatch value can only have one function associated with it
21:10	brehaut	and its an isa? test
21:10	methods	cause that lets you add matches later
21:10	brehaut	a switch statement is not late bound
21:18	icey	do any of you use amazon's simpledb with clojure?
21:24	brehaut	icey: http://www.clojure-toolbox.com/ lists two libraries for simpledb, rummage and sdb so i presume there are some people using it
21:27	icey	brehaut: i'm using a fork of the sdb library from there (https://github.com/bapehbe/sdb) but it's not behaving the way the examples & tests do, so I figured I'd see if there were people using it so I could ask them if I was missing something obvious. Thank you though :)
21:27	icey	I'll try out rummage and see if that works a little better
21:30	icey	brehaut: by the way, "A brief overview of the Clojure web stack" was amazing
21:30	brehaut	thanks :)
21:51	methods	how's that ? https://gist.github.com/21e3aed658edd7b0f785
21:58	brehaut	methods: still greenspunned
21:59	methods	yes I know :] I can't magically add it .. oh wait let me hack up the vm really fast :]
22:00	amalloy	methods: i wrote a whole vm while you were doing that. decided to call it nop
22:00	methods	lol
22:00	brehaut	amalloy: is it metacircular?
22:00	methods	what ?
22:01	methods	lol fill me in here...
22:01	amalloy	http://www.esolangs.org/wiki/Nil
22:02	Scriptor	methods: http://en.wikipedia.org/wiki/NOP
22:02	amalloy	my implementation is basically the same but i changed the name to NOP
22:03	methods	no matter what defmulti has to run at runtime right ? there is no way to do it at load time cause the arguments can be of any type ?
22:03	methods	at any time..
22:03	methods	I'm just doing this to see the trade offs or benefits
22:03	methods	I'm wondering now how this shiny little class can help my existing code get out of some kind of trap
22:04	methods	or spaghetti'd class's as Rich HIckey put it
22:05	brehaut	methods: once again, if you need late bound decisions over multiple values, then it will help
22:08	cemerick	I think the ML is teetering on the brink at this point.
22:08	cemerick	:-(
22:09	brehaut	cemerick: icey was asking about rummage earlier; thats your simpledb lib right?
22:09	cemerick	yup
22:09	dnolen_	cemerick: ? seems the same as usual to me :)
22:09	cemerick	dnolen_: it's actually taken a serious turn downwards in the past 2-3 weeks IMO.
22:10	cemerick	There needs to be a designated community manager or…something. I need to go read some Clay Shirky, etc.
22:10	cemerick	icey: come find me tomorrow, I'm toast for tonight
22:11	dnolen_	cemerick: really? current crop of threads seem like the usual fare. The only serious downturn was Steve Yegge thread.
22:13	dnolen_	cemerick: I've long since stopped reading any Ken Wesson post that isn't actually answering someone's question.
22:17	Scriptor	cemerick: what do you consider to be the discussion going off the rails, just when it goes off topic?
22:18	Scriptor	what about non-clojure talk in #clojure when there's no question being asked?
22:26	amalloy	hah, fun times. i solved http://4clojure.com/problem/104 with no parens or curly braces
22:31	ischyrus	When I start Leiningen I get this message: "IllegalArgumentException: Don't know how to create ISeq from: java.lang.Character"
22:32	ischyrus	what would cause that?
22:37	methods	hm so clojure is lazy like haskell ?
22:40	methods	hm the transactional memory reminds me of atomic variables that you can use in device drivers
22:46	dnolen_	methods: Clojure is not lazy, but it does make heavy use of lazy sequences.
22:46	methods	ok i guess I'll figure that out later
22:47	dnolen_	methods: atomic variables are probably more like atoms in Clojure.
22:47	methods	hm ?
22:49	dnolen_	methods: can you coordinate changes between two atomic variables ?
22:49	methods	not sure
22:49	dekuderp	I have a vague problem, and I can't really figure out how to solve it in lisp
22:50	dnolen_	methods: it doesn't sound like it from the pages of Linux Devices Drivers that google barfed up. sounds more like Clojure atoms.
22:50	dekuderp	I want to create a function that handles events, but I don't really know how to
22:52	amalloy	(fn [event] (println event)) is pretty much all you need?
22:52	methods	dnolen_: yea idk i know it reduces down to like a machine instruction or something that is atomic ..
22:53	dekuderp	(fn [events] (call-function (:function-handler (first events) (first-events)) is more of what I want to do
22:53	dnolen_	methods: yes, an particular instruction is guaranteed to be atomic on that reference. STM is quite a bit fancier - more like DB transaction you can coordinate changes between many references.
22:54	dekuderp	so the function-handler would be a reference to the function(s) which should be called given the changes that the event represents
22:54	methods	yea i mean underneath though it has to use locking anyway right ?
22:55	dekuderp	basically I want to make it so that someone else can plop in a new event-type, encode the functions to call in the event-type, and never have to modify the event handling function
22:55	dekuderp	for*
22:58	methods	brehaut: obviously you could still use defmulti beneficially without needing to bind it lately ? i mean what if you had a physics lib and defined a bunch of collision types like [:sphere,:plane] I could picture that all being
22:58	methods	done in the same area without needing to late bind it from other places ? or is there something better for that then ? and where does the isa? test ever happen ? based on my implementation i never called anything that was testing
22:58	methods	types .. i simply tested that special = desired value ... but that's not the same as the type of an object ..
23:00	methods	dekuderp: something like a basic event system ? event.register("some event name"){ /* code to get invoked on the event */ } .. later .. event.publish("some event name") ?
23:01	amalloy	dekuderp: sounds like you want to talk to methods about using multimethods
23:01	methods	depends on if he wants multiple handlers to listen for the same event
23:02	dekuderp	yes, I would like multiple methods listening for the same event
23:02	dekuderp	multimethods you say?
23:02	methods	does clojure offer any kind of classes ?
23:03	methods	if not from the little I have read you'd want to create a state that holds your events and handlers and then some functions to publish/subscribe
23:03	dnolen_	methods: multimethods separate hierarchies from dispatch, you can define your own hierarchies w/o involving types. Clojure doesn't do = to match multimethods, it uses isa?
23:04	methods	at least that's all i could think of right now and I never wrote 1 line of clojure
23:04	dnolen_	(derive ::car ::automobile)
23:05	dnolen_	methods: ^ I've defined a relationship w/o actually creating an actual type.
23:05	methods	I don't get where isa? is used though.. (defmulti encounter (fn [x y] [(:Species x) (:Species y)])) that basically looks like it's yanking :Species out of a hash (def b1 {:Species :Bunny :other :stuff}) ..
23:05	dnolen_	method: you also have deftype/record, but they offer a tiny subset of what you might be used to coming from traditional OO langs.
23:06	methods	so clojure supports building blocks then i guess kind of like scheme ?
23:06	methods	(not that I even know what scheme offers)
23:07	dnolen_	methods: sort of except that Clojure ships with a lot of meaningful interfaces, you reuse as much as you create.
23:08	methods	so where in this implementation would there be an isa? test ? https://gist.github.com/21e3aed658edd7b0f785
23:08	dnolen_	if _pattern == pattern
23:08	methods	hm wait a second.. so then what does isa? actually do ?
23:09	tufflax	Does anyone know how I can speed this up? dnolen_, amalloy told me you might know :P http://pastebin.com/bVHRKaKz
23:09	dekuderp	wait what does "::" represent in clojure so I can google it
23:10	jsnikeris	Hi all. Fairly basic question here. How can I avoid the repitition found in the last few lines of the following gist? e/at is a macro found in Enlive where a series of selector/transformation pairs are written like so: https://gist.github.com/1091232
23:10	dnolen_	methods: there a lot of hardwire behavior in multifn. Collections needs to be traversed checking isa? on each element. multifn have lot of optimization logic to make this stuff fast.
23:11	tufflax	dekuderp A keyword that begins with two colons is resolved in the current namespace (The Reader, clojure.org)
23:11	methods	isa? to me sounds like a.class == Something though ? but in this case it looks like it's just testing 2 scalars to be equal ?
23:11	amalloy	jsnikeris: because at is a macro, the only way to avoid repetition in it is to write another macro that expands into an invokation of (at) that's more to your liking
23:12	dnolen_	tufflax: sorry not feeling like optimizing code at the moment, but I can tell you that you need type hints for those asets to perform well.
23:12	jsnikeris	amalloy: ah OK
23:12	tufflax	ok, dnolen_ :)
23:13	dnolen_	tufflax: my advice to stop a moment a figure out some minimum operation on arrays, discover what is required to make them fast outside your problem.
23:14	amalloy	dnolen_: one of these days i'll need to write fast arithmetic operations for myself, and then i can stop telling people to ask you
23:14	dnolen_	tufflax: your code should trounce the Python once you've sorted that out.
23:16	dnolen_	methods: not isa? looks at the hierarchy, but the Java class hierarchy and a global tag hierarchy (or a custom one if you've provided it)
23:17	methods	wow I'm confused now
23:17	methods	I mean :Bunny to me just looks like a non mutable string or something
23:18	dnolen_	methods: you can establish relationships between fully namespaced keywords. (derive ::bunny ::animal)
23:18	dnolen_	(isa? ::bunny ::animal) => true
23:18	methods	what about the case where you want to define a handler regardless of the order of the arguments ? like you want to define the same handler for [:Bunny,:Lion] and for [:Lion,:Bunny] but obviously you want to be able to reference
23:18	methods	the correct one in your handler ...
23:20	dnolen_	methods: return a set from your dispatch fn, your fn will get the arguments in the right order.
23:20	methods	I guess at that point they'll probably just tell you to always order it the same .. or sort it first and define your callbacks in the sorted way
23:20	dnolen_	methods: you could of course stop speculating and start writing some Clojure ;)
23:21	methods	oh , this is bigger though , I'm trying to understand usage of them and how it could help my existing code
23:21	methods	i really want to understand the benefits of this approach over classical oo styles and apply it
23:22	methods	when you said , "return a set from your dispatch fn" what did you mean ? It's already returning [(:Species x) (:Species y)] is there a way to sort that quickly or something ?
23:28	dnolen_	methods: https://gist.github.com/1091247
23:28	methods	(into #{} [x y])
23:28	methods	what is that ?
23:28	dnolen_	methods creating a set
23:29	methods	so a set has no order basically ?
23:29	dnolen_	methods: no.
23:29	Scriptor	methods: right, it's the mathematical definition of a set, an unordered collection of unique elements
23:30	Scriptor	,(cons 2 #{1 2 3})
23:30	clojurebot	(2 1 2 3)
23:30	Scriptor	scratch the unique part
23:31	Scriptor	wait
23:31	Scriptor	,(conj 2 #{1 2 3})
23:31	clojurebot	java.lang.ClassCastException: java.lang.Integer cannot be cast to clojure.lang.IPersistentCollection
23:31	Scriptor	,(conj #{1 2 3} 2)
23:31	clojurebot	#{1 2 3}
23:31	Scriptor	unscratch the unique part
23:32	dnolen_	methods: https://gist.github.com/1091247
23:32	dnolen_	^ hierarchy w/o types
23:33	methods	yea just weird that ::car is never defined or anything
23:34	methods	i guess it really doesn't have to be defined ?
23:35	methods	I'm just not sure what (derive) would do then besides allowing 1 thing to look like another ?
23:35	methods	it wouldn't actually like extend any type of functionality would it ?
23:36	methods	hm so you could use vectors or sets and define methods for both ? I assume then you need to order your defmethod's from most specific to least..
23:37	dnolen_	methods: no.
23:37	dnolen_	you can define them in any order.
23:37	scottj	methods: why do you always add a space before your "?" ?
23:37	methods	idk I'm nuts..
23:38	methods	I guess I like it to stick out
23:38	scottj	methods: ok you're pretty consistent about it
23:39	methods	lol it's funny though cause I type it something like? and then go back and add a space... I guess my brain believes the ? belongs to the sentence not the word.. or I just want it to stand out more or something.. idk..
23:39	dnolen_	yowza: http://arxiv.org/abs/1107.3539
23:39	methods	s/something/sometimes
23:39	lazybot	<methods> lol it's funny though cause I type it sometimes like? and then go back and add a space... I guess my brain believes the ? belongs to the sentence not the word.. or I just want it to stand out more or sometimes.. idk..
23:39	methods	what's up with that ^ ?
23:40	scottj	you used s/...
23:40	methods	WOW!
23:40	Scriptor	lazybot detects that and actually does the substitution
23:40	methods	yea that rocks !
23:40	methods	I'm going to add that to my bot right away .. actually that would be a good plugin in your client perhaps ..
23:40	scottj	would be nicer if it highlighted the change
23:41	methods	yea you could do that with unicode i think
23:41	scottj	or just bolding/coloring format strings I think irc supports
23:42	methods	\u0002
23:43	methods	that's for bold
23:43	methods	should be really easy to add that to the bot http://oreilly.com/pub/h/1953
23:44	methods	does it also support /g and other options ?
23:45	methods	what about backrefs ? lol .. hopefully it doesn't allow me to inject variables names or call a method in the replacement portion..
23:51	Scriptor	going through the lazybot source, it's...interesting
23:51	methods	oh it's public ?
23:51	Scriptor	methods: yep, https://github.com/flatland/lazybot/tree/master/src/lazybot
23:51	Scriptor	https://github.com/flatland/lazybot is the main repo
23:53	brehaut	Scriptor: comparing lazybot and clojure bot is particular interesting
23:54	brehaut	s/e b/eb/
23:54	lazybot	<brehaut> Scriptor: comparing lazybot and clojurebot is particular interesting
23:54	methods	does clojure support native regex testing like you might see in perl ?
23:55	brehaut	(re-seq #"[a-c]+" "aabcedfeaaba")
23:55	brehaut	,(re-seq #"[a-c]+" "aabcedfeaaba")
23:55	clojurebot	("aabc" "aaba")
23:55	methods	cool
23:55	brehaut	for instance
23:55	brehaut	but res are not fns (for performance reasons)
23:55	methods	I'm trying to remember how to match any character and then right after that match anything except that character... i don't think backrefs are available in the search string right away
23:55	methods	fns ?
23:56	brehaut	ifn specifically; anything callable like a function
23:56	brehaut	(map (juxt class ifn?) [inc [] (symbol "foo") :foo "str" #"re" {} #{} ()])
23:57	brehaut	,(map (juxt class ifn?) [inc [] (symbol "foo") :foo "str" #"re" {} #{} ()])
23:57	clojurebot	([clojure.core$inc true] [clojure.lang.PersistentVector true] [clojure.lang.Symbol true] [clojure.lang.Keyword true] [java.lang.String false] [java.util.regex.Pattern false] [clojure.lang.PersistentArrayMap true] [clojure.lang.PersistentHashSet true] [clojure.lang.PersistentList$EmptyList false])
23:59	amalloy	#"(.)((?!\1).)" probably works, methods
23:59	amalloy	&(re-seq #"(.)((?!\1).)" "aabb")
23:59	lazybot	⇒ (["ab" "a" "b"])