#clojure – 2009-07-20

2009-07-20

03:17	yason	Vkthkstt!
03:28	yason	dang
03:28	yason	writing passwords blinded with a dead display is bad :)
06:09	Fossi	hi
06:10	Fossi	i just stumbled over another piece of lisp-1 fun again: having a struct named foo and normally calling your variables foo as well
06:11	Fossi	make a typo in the parameter list and it won't even fail on you, only retun nil for a value of the struct
06:11	Fossi	so, note to self: name structs struct-foo
06:29	AWizzArd	Fossi: yes, I also stumpled over that some months ago. But I did not decide yet if this has more to do with Clojure being Lisp-1 or being dynamically typed.
06:29	AWizzArd	Why would one name variables after their type in statically typed langs?
06:51	cky	Fossi: I can't comment on Clojure convention, because I'm new to it, but in Scheme, record type objects are usually bracketed with angle brackets.
06:51	cky	e.g., <foo>
06:55	AWizzArd	cky: in Clojure it would not be typical to put names of structures into angle brackets.
06:57	cemerick	although I smile a little every time I'm reminded that clojure is perfectly happy with symbols like <foo>...forgive me for my java/python background :-)
06:58	AWizzArd	It could be the convention for a project. If it is used consistently then I wouldn't mind.
06:59	AWizzArd	For example, we use fnparse (thanks for the tip hiredman) and all rules begin with a !.
07:05	Chousuke	cemerick: I think clojure is fine with any unicode character :P
07:06	cemerick	yeah, almost :-)
07:06	Chousuke	actually, it even accepts '　' as a symbol character
07:06	cemerick	right, just not through the reader
07:06	Chousuke	yes it does.
07:07	Chousuke	that's a double-width space :)
07:07	cemerick	ah, couldn't tell that in irc :-)
07:07	Chousuke	user=> (def funky　symbol 5)
07:07	Chousuke	#'user/funky　symbol
07:07	Chousuke	user=> funky　symbol
07:07	Chousuke	5
07:07	Chousuke	:P
07:07	Chousuke	I think that's a bug, though.
07:08	AWizzArd	The biggest problem with that will be actually typing these unicode chars.
07:08	Chousuke	it's not too difficult with an input method editor :P
07:10	Fossi	worse i've seen was sql which had right-tp-left markers in it
07:11	Fossi	*t
07:11	Fossi	init was like: insert into foo values (";("somestring
07:12	Fossi	makes you go 'wtf?'
07:12	AWizzArd	(def √² 1.4142135)
07:16	cemerick	AWizzArd: if you're on a mac, then typing such things is incredibly simple (e.g. no alt+... codes to remember)
07:17	AWizzArd	i see
07:17	cemerick	√ is just option-v for example -- there are even some mac keyboards that have the 'special' characters printed on the front face of the key
07:17	Fossi	only that all the other letters are on a weird comb
07:17	Fossi	key combo
07:20	cemerick	ah, this is the one I was thinking of: http://matias.ca/tactilepro
07:20	Chousuke	Fossi: job security? :p
07:21	Fossi	and the infallable apple-q
07:21	Chousuke	my mac layout has no quick key for lambda :(
07:21	Chousuke	opt-l gives ﬁ
07:21	rys	heh, the unicode chars in my term while we discuss this made cemerick's 2nd to last comment appear to come from me
07:21	cemerick	Chousuke: that's easy to change
07:21	rys	(for me at least)
07:22	Fossi	so my keylayout is totally different anyway :)
07:22	AWizzArd	I am using the NEO layout (not qwerty), and with it I also have easy access to greek symbols and mathmatical symbols and programmers symbols.
07:23	Fossi	yeah, neo is nice as well
07:23	Chousuke	but does it support APL?
07:23	AWizzArd	Fossi: it is following the same ideas like dvorak, but more specialized on german, while dvorak is a bit better for english.
07:25	AWizzArd	Ah ok, that's why you know neo
07:25	cky	Hehehehe. :-)
07:25	Fossi	i decided to learn dvorak though because it's better supported by hardware manufacturers
07:25	Fossi	and the difference is not as big with a nice layout like this keyboard has
07:26	AWizzArd	Well, my keyboard also has good support: http://www.daskeyboard.com/
07:26	Fossi	if you haven't you should check it out. best ever :)
07:26	Chousuke	there's a Finnish optimised layout called DAS. It has some characters that are officially used in Finnish for certain loanwords but which no-one really uses :P
07:26	AWizzArd	As it does not show any printings on the keys... it fits perfectly.
07:26	Fossi	AWizzArd: well, i would annoy my collegues to death with that
07:26	Fossi	pair programming gets kinda hard :)
07:26	Chousuke	partly because they're impossible to type with Finnish qwerty.
07:26	AWizzArd	I ask my workmates to type blind g
07:26	cky	AWizzArd: That's the real way to type! :-)
07:27	cemerick	hrm, we should do a poll of clojure programmers' nationality
07:27	Fossi	actually i find it easier to type dvorak on daskeyboard then on a qwerty
07:27	cky	My keyboard still has qwerty keycaps printed on, so it doubly confuses my workmates, who cannot hunt-and-peck. :-P
07:27	AWizzArd	very good
07:28	rys	I can't remember the last time I looked at my keyboard to type anything
07:28	cky	rys: Exactly!!
07:28	rys	The keys could be blank
07:29	cky	Whereas, back when I was learning Dvorak, I shifted the keys on my laptop at the time, with the severe downside that the home keys aren't where they are supposed to be. :-(
07:29	Fossi	now it's much better
07:30	cky	By home keys, I mean the bumpy keys where U and H are in Dvorak. :-)
07:30	Fossi	huh? i though you meant physically
07:30	Fossi	ah, ok
07:30	Fossi	never had a problem with that really
07:30	cky	Well, without the bumpy keys, my hands tend to drift too much.
07:31	Fossi	then again a divider in the middle helps a whole lot
07:31	cky	...that is true.
07:31	Fossi	extra points for it being the enter key :D
07:31	cky	:-)
07:32	cky	Well, here in the US it's not easy to find a Dvorak keyboard, but that doesn't mean I will use any layout other than Dvorak (if I ever learn German I'll learn NEO too :-P).
07:33	Fossi	i ordered mine from the us actually
07:33	cky	nods Yes, I suppose I should find some suppliers.
07:33	Fossi	it's not like they have them in store
07:33	cky	nods
07:33	Fossi	as said: reallt check out typematrix
07:33	Fossi	it's awesome
07:34	cky	Thanks! :-)
07:38	AWizzArd	Fossi: try this one please: http://schnell-schreiben.de/stv2/
07:38	fsm	Hi, I have made a raytracer as a project to learn cloure. Here is a pic. http://solardriftwood.com/aa.png
07:38	AWizzArd	Or the english version (measuring typing speed): http://speedtest.10-fast-fingers.com/
07:38	fsm	clojure*
07:39	AWizzArd	fsm: did you write the RT from scratch? Or used Harrops version?
07:39	fsm	I wrote it from scratch
07:39	fsm	I do not know what Harrops refers to
07:39	cemerick	fsm: very nice! :-D
07:40	AWizzArd	fsm: good good
07:40	fsm	Since then it does texture mapping and bump mapping, but I don't have a nice image of that yet
07:40	fsm	But, I have a performance issue relating to boxed primitives
07:41	fsm	I have profiled and most of the bottlenecks are in operations of vectors of doubles [x y z] and I am trying to find the fastest representation
07:41	fsm	When I converted to using make-array and aget, instead of [] and nth, I lost 30% performance
07:41	AWizzArd	you probably introduced reflection then
07:42	fsm	When I profile, I see millions of calls to Number.ops methods where I would hope for native arithmetic
07:42	fsm	I turned on reflection warnings, there's no reflection
07:42	fsm	The other weird thing, is I tried making some vector math into macros instead of functions, that caused a 20% slowdown
07:42	fsm	I guess the java hotspot optimizer is very clever if you call the same function a lot
07:43	cemerick	fsm: perhaps the unchecked math fns are appropriate?
07:43	cemerick	,(doc unchecked-add)
07:43	clojurebot	"([x y]); Returns the sum of x and y, both int or long. Note - uses a primitive operator subject to overflow."
07:43	cemerick	etc....
07:43	fsm	I saw that, but i am using floating point unfortunately
07:43	fsm	I tried adding type hints also, but that seemed to cause a performance hit, i guess more redundant boxing/unboxing was introduced
07:44	cark	do you coerce your floats ?
07:44	fsm	Say I have two vectors [1.0 2.0 3.0] and [4.0 5.0 6.0] and I want to add them together, is there a faster way to access the variables than nth
07:44	fsm	I tried coercing the floats, that caused a small performance drop
07:45	fsm	I am perplexed that using make-array to make a double array is so slow
07:45	Chousuke	it's slow because it does a full copy :/
07:46	cemerick	that, or the array is java.lang.Float[] instead of float[]
07:46	fsm	I was using make-array Double/TYPE which refers to double
07:46	fsm	Unless I am mistaken
07:46	cemerick	no, you're not :-)
07:46	cark	nope this is correct
07:47	fsm	So, even when I use macros and everything expands out to just basic arithmetic and aget, or to using nth, millions of calls to Numbers.obs.* show up
07:47	fsm	ops
07:47	fsm	I mean
07:47	Chousuke	hmm
07:47	cark	and you're using the -server flag when starting java ?
07:48	Chousuke	are you passing more than two arguments to +?
07:48	fsm	I have nested my operator +, that caused a big speed boost
07:48	fsm	I have not been using -server flag
07:48	cark	ah, this should help a lot
07:48	fsm	OK I will research that
07:48	cemerick	yeah, the client compiler is completely different
07:49	cemerick	hrm, the only thing preventing support for unchecked ops in Numbers are more overloads :-)
07:49	fsm	Back in a minute, going to do a performance check
07:50	cark	you need to take the warm up into account, compilatin only occurs after quite a few runs of each function
07:50	fsm	Yep, I have written a timer macro that times only the actual executions
07:51	fsm	Anyway, I must say that writing this project is a very rewarding experience
07:52	fsm	The tools of functional programming are like having a CNC machine compared to hammer and chisel
07:52	cemerick	fsm: In general, you need to let whatever code paths you're benchmarking "warm up" at least a half-dozen times before most of the compiler optimizations have been baked in.
07:53	fsm	Yes, with raytracing the same routine is called for each pixel on the screen, causing a great many runs
07:54	Chousuke	It sounds to me that dealing with arrays in Clojure is somehow unnecessarily difficult :/
07:57	fsm	OK, using -server results in a consistent 3% speed boost
07:58	fsm	Anyway, I will clean up the code and post it somewhere in the next day or two
07:59	fsm	Meanwhile my algorithmically equivalent Objective-C version was on the order of 10x faster
08:00	fsm	But Clojure is an excellent project, I look forward to solving this problem
08:01	Chousuke	Is there any easy way of determining where boxing happens? :/
08:02	cemerick	essentially at any function boundary, aside from unchecked-* ops AFAIK
08:02	fsm	Does that include aget
08:02	AWizzArd	fsm: maybe you can inline here and there
08:03	AWizzArd	,(doc definline)
08:03	clojurebot	"([name & decl]); Experimental - like defmacro, except defines a named function whose body is the expansion, calls to which may be expanded inline as if it were a macro. Cannot be used with variadic (&) args."
08:03	Chousuke	cemerick: can you tag functions to tell clojure that they return primitive values? :/
08:03	fsm	I tried converting everything to macros already, unfortunately that reduced performance, I think by reducing the effectiveness of the hotspot optimizer
08:04	cemerick	not that I know of, no
08:04	fsm	But if aget is boxing the value it returns, that could be the crux of the problem i am having
08:05	Chousuke	fsm: are you doing (let [foo (double (aget ...))])? or something
08:05	cemerick	fsm: macros don't necessarily impact the optimizer -- that is determined by the code that your macros emit. So, unless the code they're emitting is more efficient than your normal fns, the macro usage will be slower.
08:05	Chousuke	cemerick: expanding macros bloats the code though.
08:06	fsm	I am not using that let syntax, because it would mean I have to unpack and repack my vectors to do operations on them.
08:06	cemerick	I think the bottom line issue here is that there's no unchecked math for floating points / doubles
08:06	fsm	Which is not very lispy
08:06	AWizzArd	fsm: do you have a short and simple example where a macro slowed down your code?
08:06	Chousuke	fsm: IIRC the optimisation tips page recommends that all primitive "casts" be done in a let, though :/
08:06	AWizzArd	The funny thing is that in the compiled version that you execute no macros exist anymore.
08:07	fsm	(defn dot [v1 v2] (+ (+ (* (vx v1) (vx v2)) (* (vy v1) (vy v2))) (* (vz v1) (vz v2)))))
08:07	fsm	^^ rewriting that to be a macro slowed down my code
08:08	cemerick	Chousuke: the perf of the fns emitted by the macro is way more important than the 'size' of what it's emitting, though.
08:08	fsm	the vx/vy/vz are wrappers for either nth or aget - vx v1 = (aget v1 0)
08:08	fsm	and when I make vx/vy/vz into macros too, even more performance drop, but only 5% or so
08:08	Chousuke	cemerick: well, more code equals less effective use of cache.
08:08	Chousuke	cemerick: which may make a huge difference, if you're unlucky.
08:08	fsm	I tried representing my vectors as [1.0 2.0 3.0] and as make-array
08:09	cemerick	Chousuke: true, true.
08:09	fsm	using make-array/aget instead of [] and nth caused an overall 30% speed drop
08:09	Chousuke	fsm: that dot function you pasted is not doing primitive math, though :/
08:10	cemerick	Chousuke: which isn't avail. for floats/doubles
08:10	fsm	I wrote a version that was (defn dot [#^doubles v1 #^doubles v2]
08:10	fsm	and that was slower
08:11	Chousuke	cemerick: hm :/
08:11	fsm	if i define vx/vy/vz to be macros that resolve to (aget v1 n), I get bad performance but it should be operating on primitives
08:11	fsm	but in the profiler i see Number.ops being called
08:12	Chousuke	but if what cemerick says is true and primitive ops are not available for doubles, then boxing is inevitable :/
08:12	Chousuke	but, raaah
08:12	fsm	oh, I misread that
08:12	Chousuke	GHC took over an HOUR to compile and then it dared fail at the end.
08:12	cemerick	well, there's no overloads for the unchecked math in Numbers shrug
08:13	cemerick	there may be a good reason for that that I'm not thinking of, I suppose
08:14	fsm	The java_interop page shows an example working on a java array of primitive floats, supposedly
08:14	fsm	Anyway, thanks to everyone
08:15	fsm	I will post the code tomorrow and if anyone wants to experiment on it, they are welcome
08:24	fsm	Hmm in RT.java, aget takes an array of primitives and returns a primitive
08:24	fsm	and in core.clj, aget is defined as {:inline (fn [a i] `(. clojure.lang.RT (aget ~a ~i)))
08:24	fsm	does that call into clojure.lang.RT cause the return value to get boxed?
08:25	fsm	The docs suggest that values passed to a function are boxed, so perhaps the return value is too?
08:25	Chouser	generally, yes. but macros and :inline are an exception.
08:26	Chousuke	macros don't get the actual value anyway :)
08:26	Chouser	right. both macros and :inline expand at compile time and thus the call "disappears"
08:27	Chouser	in this case what's left is a Java interop call which is not necessarily boxes.
08:27	Chouser	boxed
08:28	fsm	Anyway it be super fast, it boils down to a static function that does only return xs[i];
08:28	fsm	should be*
08:29	fsm	It's getting too late for abstract thinking, time for sleep.
08:29	fsm	Thanks to everyone for your help.
08:38	Fossi	is it bad to (apply str (rest word))?
08:38	Fossi	s/word/some-string/
08:38	AWizzArd	not if you need the result
08:39	Chousuke	,(doc subs)
08:39	clojurebot	"([s start] [s start end]); Returns the substring of s beginning at start inclusive, and ending at end (defaults to length of string), exclusive."
08:39	Chousuke	probably a fair bit faster :P
08:39	Fossi	that kinda was the question, sorry
08:41	Chousuke	though sometimes you do need to work with char sequences. str uses a StringBuilder internally so at least it's faster than naive string concatenation in java :)
08:42	Fossi	so (str (Character/toUpperCase (first "foo")) (subs "foo" 1)) should be better then (apply str (Character/toUpperCase (first "foo")) (rest "foo"))
08:42	Fossi	*than
08:42	Fossi	my engllish is so borked today
08:43	Chouser	I'd recommend shooting for clarity and maintainability first -- worry about speed only if you have to.
08:44	Fossi	well, imho they are kinda both readable, i do not wonder about performance so much, but rather about which would be considered better style
08:47	Chousuke	hmh
08:48	Chousuke	I wonder which of my installed ports depends on x11 :P
08:49	Chouser	I think 'str' is less complex than 'apply str', and you don't have to think about whether the use of 'rest' vs. 'next' is important, etc. I'd vote for the first form.
08:50	Chousuke	kind of annoying, trying to upgrade ports and then something tries to install all of X11
09:11	Fossi	although they are kinda 'slacking off' lately
09:13	Jomyoot	do you guys prefer light on dark or dark on light?
09:13	jdz	dark on light is usually easier on the eyes
09:14	Jomyoot	why do the textmate geeks use light on dark then?
09:14	weissj	can someone tell me the easiest way to "un"-lazy a sequence? the laziness is causing this not to work: (map await (map #(send-off (agent %) do-one-file targetDir) mylist)))
09:14	jdz	they are geeks?
09:14	Jomyoot	I followed their convention for years
09:14	Jomyoot	kiddies
09:14	Jomyoot	what u call them
09:14	jdz	well, i meant that as an answer
09:15	cemerick	weissj: you probably want doall
09:15	weissj	,(doc doall)
09:15	clojurebot	"([coll] [n coll]); When lazy sequences are produced via functions that have side effects, any effects other than those needed to produce the first element in the seq do not occur until the seq is consumed. doall can be used to force any effects. Walks through the successive nexts of the seq, retains the head and returns it, thus causing the entire seq to reside in memory at one time."
09:15	chessguy_work	the first two test functions on http://blog.objectmentor.com/articles/2009/07/19/uncle-bob-jsps-learning-clojure are basically reduce and map, respectively, right?
09:15	cemerick	or maybe dorun, if you don't care about the results of the map
09:16	weissj	cemerick: i care about getting the entire seq from the inner map
09:17	weissj	in other words i want the entire inner map calculated before any awaits are done
09:17	chessguy_work	,(reduce + [1 2 3])
09:17	clojurebot	6
09:18	jdz	good thing i can easily change the brightness of the screen
09:18	jdz	and my laptop actually does it automatically
09:19	Fossi	i had a script a while back that switched between light and dark mode :)
09:20	chessguy_work	i think it's something like (defn roll-list [game list] (reduce roll (conj game list))) but i don't have an interpreter in front of me
09:20	cemerick	weissj: then I think it'd be (map await (doall (map #(send-off ...))))
09:20	cemerick	I've never used agents though, so that's just a guess, really
09:20	weissj	cemerick: i'll give it a try, thanks!
09:21	chessguy_work	(crickets chirping)
09:24	chessguy_work	,(let [x 3] x)
09:24	clojurebot	3
09:25	angerman	how do i cast a class to a different interface?
09:25	chessguy_work	,(let [roll (fn [g p] (conj g p))] (roll [2] 3)
09:25	clojurebot	EOF while reading
09:25	angerman	e.g. JRubyScriptEngine to Invocable
09:25	chessguy_work	,(let [roll (fn [g p] (conj g p))] (roll [2] 3))
09:25	clojurebot	[2 3]
09:27	Chouser	weissj: when creating/sending/awaiting an agent all at once like that, you might prefer 'future'
09:27	chessguy_work	,(let [roll (fn [g p] (conj g p)), roll-list (fn [g l] (reduce roll (conj g l)))] (roll-list [] [1 2 3]))
09:27	clojurebot	[1 2 3]
09:27	angerman	while in java i"d just do (Invocable)variable ...
09:28	Chouser	angerman: you generally don't need to cast. what are you trying to do?
09:28	cemerick	angerman: why are you looking to perform a cast? Such a thing is essentially not present in clojure, as it's dynamically typed.
09:28	weissj	Chouser: i will look into 'future', thanks :)
09:28	angerman	Chouser, cemerick that's what I expected
09:29	angerman	I'm trying to call invokeFunction on a jruby Script Engine
09:29	cemerick	angerman: if you're looking to invoke a method on an object, and you want to avoid reflection, you can type-hint the object
09:30	cemerick	(.invokeFunction script-engine-obj ...more-args...) will do it
09:30	cemerick	(.invokeFunction #^ JRubyScriptEngine script-engine-obj ...more-args...) if you want to avoid reflection
09:30	cemerick	bah: (.invokeFunction #^JRubyScriptEngine script-engine-obj ...more-args...)
09:32	chessguy_work	how would i apply a function to something n times?
09:33	Chouser	,(map inc (repeat 5 2))
09:33	clojurebot	(3 3 3 3 3)
09:33	chessguy_work	ermm, sorry, i'd want 10 there
09:33	chessguy_work	though i'd want to pass in the 0 too
09:34	Chouser	I'm afraid I don't understand the question at all.
09:34	Chousuke	iterate?
09:34	chessguy_work	sorry, i'm trying to get rid of a for-like loop
09:34	chessguy_work	(defn roll-many [game n pins]
09:34	chessguy_work	(loop [i n g game]
09:34	chessguy_work	(if (zero? i)
09:34	chessguy_work	g
09:34	chessguy_work	(recur (dec i) (roll g pins)))))
09:35	Chousuke	iterate returns a seq though
09:35	Chousuke	,(drop 9 (take 10 (iterate inc 0)))
09:35	clojurebot	(9)
09:35	chessguy_work	yeah this is more like a reduce over a range, where the index is ignored
09:35	angerman	cemerick: hmm it seems the arguments are my problem
09:36	cemerick	angerman: you're getting an error?
09:36	angerman	it expects a java.lang.Object and I was giving it a String
09:36	angerman	Caused by: java.lang.ClassCastException: java.lang.String cannot be cast to [Ljava.lang.Object
09:36	cemerick	it's expecting an Object[]
09:36	Chouser	maybe varargs?
09:36	cemerick	(probably the arguments to the jruby fn?)
09:36	Chouser	ooh
09:36	chessguy_work	,(nth (iterate inc 0) 9)
09:36	clojurebot	9
09:37	angerman	cemerick: yes
09:37	cemerick	angerman: in that case, (into-array ["some" "args"]) might be what you want
09:37	angerman	cemerick: using a vector doesn't resolve it :/
09:37	angerman	hmm into-array
09:37	cemerick	vectors aren't arrays
09:37	cemerick	angerman: :-)
09:37	Chouser	actually, if it wants Object[], try (to-array ["some" "args"])
09:38	cemerick	yeah, I can never remember in what contexts a String[] isn't useful as an Object[]
09:38	rhickey_	chessguy_work: (reduce roll game (range 1 n))
09:39	jdz	rhickey_: nice one!
09:39	rhickey_	oh, you're not using n
09:39	cemerick	the fact that uncle bob is interested in clojure is interesting
09:39	jdz	a bit confusing, though
09:39	chessguy_work	rhickey_, yeah, i don't want the index
09:41	chessguy_work	,(let [roll (fn [g p] (conj g p)), roll-many (fn [g n p] (nth (iterate (roll g p)) n)] (roll-many [] 20 0))
09:41	clojurebot	Unmatched delimiter: ]
09:41	chessguy_work	,(let [roll (fn [g p] (conj g p)), roll-many (fn [g n p] (nth (iterate (roll g p)) n))] (roll-many [] 20 0))
09:41	clojurebot	java.lang.IllegalArgumentException: Wrong number of args passed to: core$iterate
09:43	rhickey_	(nth (iterate #(roll % pins) game) n)
09:44	rhickey_	the best thing to do with that bowling game is to step far away from that original logic
09:45	chessguy_work	,(let [roll (fn [g p] (conj g p)), roll-many (fn [g n p] (nth (iterate #(roll % p) g) n))] (roll-many [] 20 0))
09:45	clojurebot	[0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]
09:45	chessguy_work	shazam :)
09:46	rhickey_	the 'kata' is almost a poster child for what I think is wrong with TDD and OO today
09:46	rhickey_	http://butunclebob.com/ArticleS.UncleBob.TheBowlingGameKata
09:48	rhickey_	Write a class named “Game” that has two methods
09:48	rhickey_	roll(pins : int) is called each time the player rolls a ball. The argument is the number of pins knocked down.
09:48	rhickey_	score() int is called only at the very end of the game. It returns the total score for that game.
09:48	drewr	ugh, he distributes it in a ppt
09:49	rhickey_	the roll method returns void!!, so right away we have a stateful object. The score method is only valid at certain times.
09:49	chessguy_work	rhickey_, not in the clojure version
09:49	chessguy_work	:)
09:49	rhickey_	So with this awful premise, we start TDD, our system for robust and responsible programming - yikes
09:50	rhickey_	chessguy_work: yes, the CLojure version should be much different. It's just the point I;ve tried to make about OO and TDD, people are starting with faulty premises and never questioning them
09:51	rhickey_	3rd slie - "Clearly we need the Game class"
09:51	rhickey_	slide
09:51	angerman	cemerick: thanks.
09:51	chessguy_work	i think TDD and functional programming are approaching the problem from different directions and can meet in the middle
09:51	angerman	cemerick: whee, I can now call maruku (ruby) from clojure ... still need to work on the return type though :/
09:51	chessguy_work	(the problem of code quality in a stateful reality)
09:53	rhickey_	chessguy_work: well, there's reality and our representation of it in our programs - the latter need not be stateful to the degree it normally is in OO
09:54	chessguy_work	rhickey_, agreed, but there need not be the lack of testing of functional programs that there is either
09:55	AWizzArd	typically it is easier to test functional programs
09:55	chessguy_work	but it's done a lot less, i think
09:56	rhickey_	chessguy_work: sure, but my key point is the unquestioned presumption of stateful objects by TDD advocates using traditional OO langs - building on sand
09:56	rhickey_	but feeling good about it due to the tests
09:57	chessguy_work	well, i guess for a non-parallel project it's ok
09:57	rhickey_	chessguy_work: seriously not ok
09:58	rhickey_	I think there a lot of Clojure users now who'll testify to the increased robustness of their non-concurrent programs
09:58	chessguy_work	anyway, i think TDD leads to a lot less stateful design in general than non-TDD
09:59	rhickey_	I'd hate for people to think that FP is only for concurrency
09:59	AWizzArd	I absolutely test nearly everything.
10:00	AWizzArd	It is not responsible to not write tests (with some few exceptions).
10:00	chessguy_work	not _only_ but that's certainly a place where it thrives
10:00	Chouser	I still have only dabbled in Clojure's concurrency support.
10:00	AWizzArd	When writing professional code for applications one wants to sell means one should test-is it.
10:01	drewr	my programs are much better by not even thinking about state until forced to
10:01	drewr	...which is usually much later
10:01	chessguy_work	rhickey_, part of the premise of TDD is that it leads to code that's easier to test (because it's less stateful, though that's not usually stated) and, thus, more flexible
10:02	rhickey_	AWizzArd: I'm not trying to be anti-testing, this just seemed a good example of a conundrum I have with people advocating TDD and not questioning mutable OO - discipline on top of spaghetti
10:03	chessguy_work	i agree that it could be made more explicit, but it's there
10:03	rhickey_	chessguy_work: I haven't seen any connection whatsoever between the two - lots of examples just like this one - pokeable things with tests that poke them
10:04	rhickey_	and mock pokeable things of course
10:04	Chouser	/topic discipline on top of spaghetti ... seriously not ok
10:05	rhickey_	the only thing I want on spaghetti is a good red sauce :)
10:05	jackdempsey	hehe
10:05	drewr	Chouser: +1
10:05	clojurebot	Why are you asking him
10:05	chessguy_work	aww, man, now you guys are making me hungry
10:05	jackdempsey	haha
10:05	cark	you're missing on spaghetti carbonara !
10:05	cark	not red at all
10:06	cark	on topic, i mostly unit test data structures, and then lots of repl testing and end product testing
10:08	cark	most of the things we (i anyways) do aren't that hard to do, how wrong can you be summin an invoice from a database table ?
10:09	jdz	doing read-only stuff has some benefits
10:10	chessguy_work	oh well, back to the real world
10:10	kylesmith	quick question for someone: I'm blowing the stack on the defn on large data (> 1000), why? (defn get-bounds [objects coordinate-func]
10:10	kylesmith	"Returns a seq of the min and max coordinates"
10:10	kylesmith	(let [coords (map coordinate-func objects)]
10:10	kylesmith	(reduce #(list (map min (first %1) %2)
10:10	kylesmith	(map max (second %1) %2))
10:10	kylesmith	(list (first coords) (first coords)) coords)))
10:10	drewr	lisppaste8: url
10:10	lisppaste8	To use the lisppaste bot, visit http://paste.lisp.org/new/clojure and enter your paste.
10:11	kylesmith	sorry, I'm relatively new to irc.
10:11	drewr	kylesmith: np
10:11	Chousuke	hm
10:13	Chousuke	you could probably make that clearer if you used destructuring and vectors instead of the list function.
10:13	kylesmith	yes, of course. I'll do that.
10:16	AWizzArd	rhickey_: yes, I understood you. Automatic tests are also helpful in functional programming to protect from changes. A new coder in the company changes an old side-effect free function which still works for most cases, but for one important part it doesn't. Via Contribs test-is this can sometimes be caught.
10:17	Chousuke	kylesmith: the coordinate-function returns a seq of pairs?
10:17	lisppaste8	kylesmith pasted "get-bounds" at http://paste.lisp.org/display/83852
10:18	kylesmith	that docstring isn't the best; just a list of [[x y z] [x y z]] representing min and max
10:18	rhickey_	has everyone been ok with chunked map et al in master?
10:18	Chousuke	kylesmith: hmm
10:19	drewr	rhickey_: no issues so far
10:19	Chousuke	what kind of an object is a coordinate?
10:21	kylesmith	well, I pass in a seq containing sets of atoms, and get the center of mass. but that part works just fine. you can just pass in the coordinates directly and use identity or whatever.
10:21	rhickey_	any git fu
10:22	Chouser	git branch -m chunks scratchpad ...I think
10:23	kylesmith	Oh, and technically, the initial value to reduce is arbitrary, but it should get overwritten by the end.
10:23	jackdempsey	yea that should do it
10:23	jackdempsey	git branch (-m \| -M) [<oldbranch>] <newbranch>
10:23	jackdempsey	-M forces even if newbranch exists
10:26	Chousuke	kylesmith: something like http://gist.github.com/150361 ?
10:27	Chousuke	didn't work so well, though. no syntax colouring and I had to dig up the URL from the messages buffer
10:28	kylesmith	Chosuke: Yes, that is identical to my version, except for variable names. And it still works for 1500 elements and crashes for 2000.
10:29	drewr	kylesmith: Can you annotate with an example of call? What's a coordinate-func do?
10:29	drewr	s/of call/call/
10:29	Chousuke	kylesmith: maybe it's coordinate-func that's crashing?
10:30	kylesmith	okay, give me a second
10:31	Chousuke	coords holds on to most of the seq, too.
10:32	rhickey_	Chouser: afaik, -m is only for local branch renaming
10:33	Chousuke	I don't think it's possible to rename public branches without confusing the repositories of people who have pulled it previously
10:33	Chouser	rhickey_: hm. http://kerneltrap.org/mailarchive/git/2008/6/9/2070944
10:33	Chousuke	it's fairly simple to fix though
10:34	rhickey_	ParallelArray (used by clojure.parallel) is not making it into JDK7, so I've been playing with using forkjoin directly and supporting parallel ops for pvector et al
10:34	drewr	git push origin :chunks && git branch -m scratchpad chunks && git push origin scratchpad
10:34	drewr	that's destructive though, as Chousuke said
10:35	drewr	also assumes origin is the remote
10:36	lisppaste8	kylesmith pasted "get-bounds example" at http://paste.lisp.org/display/83853
10:36	rhickey_	so far so good, pvmap (maps a fn on a vector returning a new vector) is only 20 lines of Clojure, shows linear speedup vs (into [] (map f v)), this being the latest new improved 'into' here
10:36	drewr	you could leave the remote chunks and push a duplicate scratchpad (safest) but in this case it wouldn't matter
10:37	jackdempsey	nice rich
10:39	rhickey_	which mean on this machine (quad core) now 3.5x as fast as j.u.ArrayList
10:39	rhickey_	and in the latter case you only end up with a dangerous ArrayList, not a persistent vector
10:40	rhickey_	I'll try http://github.com/guides/rename-a-remote-branch if no one has a better idea
10:40	kylesmith	nicely done
10:40	Chousuke	rhickey_: maybe you should have multiple scratchpad branches instead of one though. it would be easier to merge the bits that are deemed good enough to go into master.
10:41	rhickey_	overall I think adding parallel ops to the Clojure data structures is going to be a huge win
10:42	Chousuke	if you had all your experiments separated as scratchpad/chunks, scratchpad/pvector, scratchpad/other-cool-thing etc, you could easily combine them by just creating a test branch and doing git merge sp/foo sp/bar (providing they don't conflict)
10:44	rhickey_	can do vectors and maps: map, reduce, possibly parallel map merge, parallel remove-keys, select-keys
10:46	Chousuke	does it parallelise a chunk at a time or something?
10:46	rhickey_	one nice thing, the new forkjoin (jsr166y) jar is only 53k
10:46	rhickey_	Chousuke: it splits up the tree recursively
10:50	lisppaste8	kylesmith pasted "get-bounds loop-recur" at http://paste.lisp.org/display/83854
10:50	kylesmith	still no luck
10:52	sh10151	xml emit functions seem to strip whitespace
10:52	sh10151	is there a way to avoid this?
10:52	Chouser	xml parse strips whitespace, and xml emit adds new different whitespace
10:52	sh10151	oh ok
10:53	sh10151	so xml parse strips whitespace
10:53	sh10151	is there a way to avoid this?
10:53	sh10151	:)
10:53	Chouser	clojure.contrib.lazy-xml has an emit that doesn't insert new whitespace
10:53	Chouser	I feel like a politician.
10:53	sh10151	that doesn't bother me as much as the missing whitespace
10:54	Chouser	answering different questions than are being asked.
10:54	kylesmith	I need to leave soon, so if anyone figures out the solution to my problem, please email me.
10:54	sh10151	all righty then
10:54	sh10151	xslt it is
10:54	sh10151	:-/
10:55	sh10151	groovy had this same asinine problem
10:55	Chouser	sh10151: afaict, both clojure high-level parsers trim whitespace
10:55	sh10151	clojure should be better than groovy, right? :-D
10:55	Chouser	sh10151: you can use java xml parsers directly (I'd recommend http://www.extreme.indiana.edu/xgws/xsoap/xpp/)
10:56	sh10151	i don't really want to parse much, just substitute in some values
10:56	sh10151	can use Transformer and set some input parameters
10:56	sh10151	so much boilerplate though
10:56	Chouser	or you can look at fixing the clojure parsers. I'd welcome a patch to lazy_xml.clj and lazy_xml/with_pull.clj that added a paramter to turn off whitespace trimming
10:56	Chousuke	kylesmith: I think I get the problem
10:57	Chousuke	kylesmith: try wrapping the map in the reduced function into doall
10:57	kylesmith	I just did that 1 second before you said, and it works!
10:57	sh10151	the default should be whitespace preservation
10:57	sh10151	otherwise you are changing the data
10:57	Chousuke	kylesmith: It just dawned on me that with a thousand coordinate, you're basically generating a lazy seq that has a thousand thunks wrapping it
10:58	Chouser	sh10151: I agree
10:58	kylesmith	yep, came to the same conclusion
10:58	rhickey_	Chouser: I think cgrand might have done that at one point...
10:59	Chouser	http://www.mail-archive.com/clojure@googlegroups.com/msg13009.html
10:59	Chouser	rhickey_: apparently so
10:59	kylesmith	thanks, Chousuke and goodnight all
11:05	lisppaste8	rottcodd pasted "object-seq" at http://paste.lisp.org/display/83855
11:05	rottcodd	is there something like object-seq built-in? I couldn't find anything
11:07	Chouser	that's a beautiful paste. Thanks for the complete working example!
11:07	Chouser	I don't know of any such function.
11:08	Chouser	Did you notice yours halts on a nil form?
11:08	Chouser	(object-seq (java.io.PushbackReader. (java.io.StringReader. "1 nil #{bar foo}"))) => (1)
11:08	rottcodd	didn't notice that
11:08	drewr	rottcodd: interesting, I have a use for that right now
11:08	drewr	hadn't thought about it that way
11:12	Chousuke	hmm
11:12	lisppaste8	rhickey annotated #83855 "object-seq w/nils" at http://paste.lisp.org/display/83855#1
11:17	Jomyoot	What's a nice EMACS theme for working with Clojure?
11:18	drewr	i find the default colors quite attractive
11:18	Chousuke	hmm... (let [eos (Object.)] (take-while #(not (identical? % eos)) (repeatedly #(read reader nil eos))))
11:18	Chousuke	not much gain from using higher-order functions in this case I suppose
11:20	Chouser	Chousuke: your version would be indentical pre-lazier
11:20	Chouser	I guess that still doesn't count as much gain. :-)
11:21	Chousuke	it does read a bit better though.
11:22	Chousuke	"take while not end of stream from <seq-of-stuff-when-read-repeately> "
11:22	Chousuke	+d
11:27	achim	you could save ~10 chars by replacing "(not (identical?" with "(not="
11:28	achim	if you're playing golf ;)
11:28	Chousuke	that's not the same.
11:28	achim	but for (Object.), it should be
11:29	Chousuke	I wonder if Object falls back to an identity comparison ./
11:31	achim	Chousuke: i believe, = falls back to .equals, which (again, i believe) should be identity comparison for Objects
11:32	Chouser	couldn't Foo.equals(x) do whatever Foo wants, even if x is just an Object?
11:33	achim	http://java.sun.com/j2se/1.5.0/docs/api/java/lang/Object.html#equals(java.lang.Object)
11:33	Chousuke	Chouser: no
11:33	Chousuke	Chouser: if x.equals(y), then it must be that y.equals(x)
11:34	achim	IIRC, (= x y) maps to (.equals x y) in the end
11:34	achim	for non-clojure things, that is
11:35	achim	Chousuke: the order matters, .equals isn't necessarily symmetric in java-land.
11:35	achim	but if you ask "eos", you won't get any false positives, because you can be sure it's nothing but an Object
11:37	rhickey_	I think identical? makes it clearer that this is a sentinel - i.e. we don't care about value at all
11:38	rhickey_	we are not testing for equality but identity - is this the eos sentinel?
11:40	rhickey_	but Java does guarantee (not= (Object.) anything-else)
12:05	Fossi	as much as i like "Programming Clojure", it's horrible for looking up things
12:09	ieure	It’s not really a reference book, is it?
12:14	Fossi	not so much
12:16	angerman	I'm trying to compile a script using ant
12:16	angerman	now my script uses javax.script.ScriptEngineManager, which I think should be in the JDK
12:16	angerman	but I fail to build the correct target :/
12:17	Fossi	maybe your jdk isn't set to the correct path?
12:17	angerman	how do I tell ant to instruct clojure to compile using the JDK?
12:19	Fossi	how can i access static public inner enums?
12:19	Chouser	OuterClass$EnumClass/ValueName
12:19	Fossi	ah. $
12:20	Chouser	It's just the JVM's internal representation for inner classes
12:20	Fossi	eh. weird.
12:20	Fossi	i mean to access it that way then
12:21	angerman	Fossi:maybe I'm too stupid to get ant to do it :/
12:21	Fossi	angerman: worked for me out of the box, so i don't really know
12:21	Chouser	java thinks it's good for . to mean lots of different things (sub-package, inner class, instance member, class member, etc.) Clojure not so much.
12:21	Fossi	the jdk path thing was just a wild guess
12:27	Jomyoot	Does Clojure have special theme support in emacs?
12:27	Jomyoot	for specific elements to clojure
12:27	ieure	Jomyoot, There’s clojure-mode.
12:28	Fossi	there's an emacs mode if that's what you mean
12:28	Fossi	with syntax highlighting
12:28	Jomyoot	is there some intersting light theme?
12:28	Jomyoot	other than than those in emacs-theme?
12:28	Fossi	more like keyword highlighting really :D
12:29	dgfitch	clojure/java newb alert: I'm trying to compile the HEAD of clojure-contrib on github, and getting [java] java.io.FileNotFoundException: Could not locate clojure/walk__init.class or clojure/walk.clj on classpath: (dataflow.clj:17)
12:29	angerman	hmm should not (compile 'foo) compile foo.clj
12:29	angerman	I get java.io.IOException: No such file or directory (maruku.clj:34)
12:30	Jomyoot	well clojure is more syntax lisp than emacs lisp
12:30	Jomyoot	clojure is more sytnax rich
12:30	Jomyoot	i meant
12:30	Jomyoot	so i hope for more highlighting capability
12:31	angerman	now that like 34 does not make any sense to me: http://gist.github.com/150429
12:34	Chouser	angerman: you got compile to work and now you're asking about line 34 of that gist?
12:34	angerman	Chouser: no, compile breaks stops with java.io.IOException: No such file or directory (maruku.clj:34)
12:35	Chouser	hm. you've got a 'classes' directory and its in your classpath?
12:36	angerman	no.
12:36	angerman	so I need that ... hmm
12:36	Chouser	,(doc compile)
12:36	clojurebot	"([lib]); Compiles the namespace named by the symbol lib into a set of classfiles. The source for the lib must be in a proper classpath-relative directory. The output files will go into the directory specified by compile-path, and that directory too must be in the classpath."
12:37	Chouser	,compile-path
12:37	clojurebot	nil
12:37	Chouser	,(doc compile-path)
12:37	clojurebot	"; Specifies the directory where 'compile' will write out .class files. This directory must be in the classpath for 'compile' to work. Defaults to \"classes\""
12:37	angerman	hmm ok
12:38	Chouser	when you try to create a file in a directory that doesn't exist, unix kicks back a "No such file or directory"
12:39	Fossi	that one got me as well :)
12:40	angerman	Chouser: thanks I'm getting closer
12:40	angerman	now I have the following issue: java.lang.RuntimeException: java.lang.ClassNotFoundException: maruku$render__34 (NO_SOURCE_FILE:0)
12:41	Chouser	you're sure that 'classes' dir is in your classpath? you restarted your jvm?
12:42	angerman	yes
12:42	angerman	i simply create a classes folder
12:42	angerman	and there is a maruku$... in that folder now
12:43	Chouser	yes, but in order to find that .class file after clojure creates it, 'classes' must be in your classpath
12:44	Chouser	a normal directory layout is for you to have src/survey/maruku.clj and classes/, and to have src and classes in your classpath
12:45	Chouser	then when you compile you should end up with a bunch of files like classes/survey/maruku*.class
12:45	angerman	magic
12:45	angerman	it did work
12:45	Chouser	great.
12:46	angerman	now I need to find out why I can't compile it with ant ...
12:58	angerman	how do i figure out the default classpath?
13:19	Lau_of_DK	default?
13:23	Lau_of_DK	Anyone using a Macbook Pro here tonight?
13:25	sh10151	I use one at home
13:26	sh10151	but I am at work right now and don't have one on me
13:26	Lau_of_DK	Ok - It doesnt matter if you have it now - I just need someone who can answer a few questions in private about it
13:26	sh10151	knock yourself out
13:27	Lau_of_DK	It does
13:55	angerman	what does this cause and how do i fix it? java.lang.Exception: namespace 'survey.maruku' not found after loading '/survey/maruku'
13:56	erohtar	angerman: it means that the namespace being defined in the file is not what it is supposed to be
13:57	erohtar	angerman: i suspect it should be survey.maraku
13:57	angerman	erohtar: hmm. ok, how am I supposed to name it?
13:57	erohtar	angerman: (ns survey.maraku)
13:57	erohtar	angerman: assuming that the survey directory is on ur classpath
13:58	Chouser	the directory containing survey is on your classpath
14:03	cemerick	yet again, I'll meaninglessly rededicate myself to posting our ant build process
14:04	cemerick	(which now only compiles clojure files that have changed since the last build -- dropped our full build time from ~60s to 10s)
14:09	weissj	I am using lancet ant stuff, but the ant functions are created by 'define-all-ant-tasks' function which repeatedly calls defmacro. but my own code isn't read properly because it calls ant functions and they aren't defined at read time. how do i fix this? i need to run 'define-all-ant-tasks' at read time, somehow.
14:10	Chouser	cemerick: not using lancet?
14:11	cemerick	no. We'll check it out at some point, but innovating in build processes is pretty low on my priority list. I've been hacking ant files for 10 years, so it's a pretty productive environment for me.
14:12	weissj	cemerick: i'm sorry :) xml as code is terrible
14:12	weissj	that's why i like lancet. groovy has a similar thing called AntBuilder.
14:12	cemerick	eh, it's horrible, but better than all the rest
14:12	cemerick	(or, all the rest that I've ever bothered to look at)
14:12	weissj	cemerick: i disagree, lancet and AntBuilder are much better.
14:13	weissj	it's real code
14:13	cemerick	right, that's where the "...that I've bothered to look at..." part comes in.
14:14	weissj	cemerick: ah. well i am trying out lancet. it's not 100% complete, but even a beginner like me can see how to get the last little bits working
14:15	weissj	anyway, can someone point me to how to get a function to run at read-time?
14:15	weissj	i know lisps are supposed to be able to do that 'whole language all the time' thing.
14:16	ieure	weissj, (defn foo [] …) (foo) ?
14:16	cemerick	weissj: you mean reader macros, I presume?
14:16	weissj	ieure: uh, how does that run the function at read time?
14:16	weissj	cemerick: i guess
14:16	cemerick	user-defined reader macros are not supported by clojure at the moment
14:16	cemerick	it's a topic of some debate, yet
14:16	Chouser	weissj: macros run at a time slightly after read, but before compile
14:18	weissj	ok, so my code "requires" lancet. lancet has a function 'define-all-ant-tasks' that defmacro's in a loop.
14:18	Chousuke	hm, wasn't there some reader form that gets evaluated at read time?
14:18	weissj	but my code doesnt' compile because it calls the functions defined by those macros that haven't been created yet.
14:19	Chouser	weissj: ah.. can you call those macros before your functions are defined?
14:19	weissj	now i can manually call 'define-all-ant-tasks' in a repl before i load my file, and that works, but that seems hackish
14:19	weissj	Chouser: but my file won't even be read in properly.
14:19	Chousuke	can't you call the macro at the top of the file?
14:19	weissj	it refers to functions that don't exist
14:20	weissj	(at read time, anyway)
14:20	weissj	or compile time, for that matter
14:20	Chouser	compile time isn't instantaneous
14:20	Chouser	earlier top-level forms are evaluated before later top-level forms are compiled.
14:20	Chouser	try it
14:20	weissj	Chouser: oh, ok, i didn't know that's how it worked. let me try.
14:24	weissj	Chouser: putting '(define-all-ant-tasks)' at the bottom of lancet.clj seems to fix it. i wonder why it wasn't already there?
14:25	Chouser	weissj: good question
14:25	Chouser	I guess you might want to define your own ant tasks first or something?
14:26	weissj	Chouser: it has a '-main' defined so i guess it was meant to run standalone instead of as a lib... not sure. seemsa lot more useful to me as a lib.
14:28	weissj	so, i've added some fixes to lancet, some ant stuff doesn't work without it. who do i submit patches to?
14:29	Chouser	lancet's not in contrib, right? So it's just Halloway and however he wants to handle it.
14:30	Chouser	you could try writing to the clojure google group, or to Halloway directly. Or fork the github repo. Not sure what he'd want.
14:30	weissj	Chouser: ok thanks
15:34	rhickey_	name game again, need a naming pattern for vector fns, and parallel vector fns, taking and possibly returning vectors, e.g. (pvmap f v) -> v and (pvreduce f v) -> x
15:34	weissj	can someone explain to me what 'partial' does? the doc doesn't make sense to me. it seems like both the function you pass in and the function it creates end up being called the same way?
15:34	hiredman	couldn't they just go in clojure.vector?
15:35	hiredman	,(partial + 1)
15:35	clojurebot	#<core$partial__4401$fn__4403 clojure.core$partial__4401$fn__4403@8ff944>
15:35	hiredman	,((partial + 1) 2)
15:35	clojurebot	3
15:35	cemerick	rhickey_: pvmap and pvreduce are no good?
15:35	weissj	oh! yeah. that's what i want. i want to use map but my function takes 2 args. i want one to come from the list i pass to map, and the other to always be the same
15:36	kotarak	dv pv ...
15:36	rhickey_	cemerick: I like them, just checking
15:36	cemerick	+1 for me
15:36	hiredman	,(map (partial + 5) (range 5))
15:36	clojurebot	(5 6 7 8 9)
15:36	kotarak	weissj: there is also #(): (map #(+ % 5) (range 5)) partial only works for the #(+ 5 %) case.
15:37	weissj	kotarak: i was about to ask, what if my partial arg isn't the first one :)
15:37	weissj	thanks
15:37	rhickey_	with a 10-line helper, pvmap and pvreduce are 10 lines each, and have no forkjoin code in them
15:37	cemerick	I'm intrigued
15:38	lisppaste8	rhickey pasted "pvmap pvreduce work in progress" at http://paste.lisp.org/display/83874
15:39	kotarak	Does .. have some advantage over ->?
15:42	rhickey_	I'm trying to get rid of most of the details, but you'll still have to know a little bit about the representation of the vectors in order to define new parallel ops
15:43	rhickey_	kotarak: not really
15:43	weissj	how come (map #(future (do-one-file % targetDir)) mylist) blocks until all the 'do-one-file' (which download and unzips a zip file) have completed? i would think by the doc of future, it would return right away bc it spawns threads.
15:44	kotarak	rhickey_: it's pretty much obsolete then, because -> is more general...
15:44	hiredman	weissj: because you are printing the result
15:44	drewr	weissj: you're not passing the fn, you're passing the value
15:44	hiredman	and keep in mind that map is lazy
15:44	kotarak	weissj: (def x (map ...))
15:44	rhickey_	kotarak: it's classic
15:44	kotarak	archaic? ;)
15:44	weissj	er, so which is it?
15:45	drewr	er, sorry, I was wrong
15:45	drewr	forgot future is a macro
15:45	weissj	ah ok, i hoped so because it really did spawn threads
15:46	drewr	:-)
15:46	weissj	so then it only blocked because i used the repl?
15:46	hiredman	weissj: and map is lazy, so unless you force the map somehow, the futures will not be generated
15:46	kotarak	weissj: you probably want something like (def x (reduce #(conj %1 (future (do-one-file %2 target-dir))) [] mylist)
15:47	drewr	weissj: what happens when you wrap it with a doall?
15:47	hiredman	or use doall, or vec, or etc etc
15:48	weissj	hiredman wins. it's because the repl printed the return value. it doesn't block if i put a 'nil' at the end of the function that calls that stuff
15:48	weissj	actually that is not quite true - it doesn't do anything either because the list is not consumed
15:49	weissj	so yeah, doall is prob the answer
15:50	weissj	now, that answers why it didn't behave like i expected in the repl. but i DO want it to block. so i just need to (doall (map (deref xx))) on it?
15:53	hiredman	oh
15:53	hiredman	weissj: you want pmap
15:53	hiredman	,(doc pmap)
15:53	clojurebot	"([f coll] [f coll & colls]); Like map, except f is applied in parallel. Semi-lazy in that the parallel computation stays ahead of the consumption, but doesn't realize the entire result unless required. Only useful for computationally intensive functions where the time of f dominates the coordination overhead."
15:54	weissj	hiredman: ooh, sweet. this function is now getting trivially short. love it :)
15:58	weissj	one thing I'm having difficulty with is 1) knowing there's already a function that does what I want and 2) even if I suppose there must be one, finding it. find-doc only gets you so far.
16:04	Chousuke	hmm
16:05	Chousuke	Clojurebot need a more sophisticated AI so you could ask it about the API :P
16:15	weissj	i suppose that is a problem with any language. all you can do is search the api and hope for a hit. half the time you don't even know the right term to search for.
16:16	weissj	i would never have known about pmap. after reading about agents, i wouldn't have thought to search for a parallel map function.
16:17	weissj	i guess we need to just read the doc on everything :)
16:17	Chouser	I recommend: reading other people's code (such as core.clj, stuff in contrib), hanging out here (watch other people's answers, ask your own questions), and finally start answering questions here.
16:17	Chouser	that last step is when you really start to learn... :-)
16:18	weissj	Chouser: yeah, i've only been at it about 2 weeks, and i already see people coming in here behind me asking even more newb questions that i already know the answer to :)
16:18	TheArthur	can I create a sparse vector in clojure?
16:18	weissj	this channel is a great resource, plus the clojure.org website and stuart halloway's book
16:19	TheArthur	and is there an easy way to create a vector full of 0 s?
16:19	Chouser	for somewhat faster bootstrapping, you can look at the couple of places that have categorized functions, to help you find fns "near" other ones in conseptual space.
16:20	Chouser	weissj: for example, 'map' and 'pmap' appear next to each other here: http://clojure.org/sequences
16:20	Chouser	TheArthur: vectors are not sparse. For that, use a sorted-map or hash-map.
16:20	Chouser	,(vec (repeat 20 0))
16:20	clojurebot	[0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]
16:21	Chouser	but there's a vector of zeros, length 20.
17:53	ieure	I’m trying to do some shebang scripting with Clojure, but I keep getting this error.
17:53	ieure	http://gist.github.com/150935
17:53	ieure	The code: http://gist.github.com/150933
17:53	ieure	I don’t get it. The code is runs, then I get an exception.
17:55	Chousuke	try removing the ns declaration
17:55	ieure	Chousuke, Same error.
17:56	Chousuke	hmh
17:57	technomancy	ieure: are you using the bash script from contrib?
17:57	ieure	technomancy, No, it’s whatever wrapper MacPorts has.
17:58	ieure	Indeed.
17:58	ieure	It would also be nice if it wasn’t insane to package up CLI tools in JARs.
17:58	ieure	Unless there’s a better way of doing it than what’s listed on WikiBooks.
17:59	technomancy	yeah, the JDK is positively useless when it comes to CLI integration
17:59	Chousuke	hm, I can't even use my clj script as an interpreter :/
17:59	ieure	You could have left out from "when" on.
17:59	technomancy	ieure: a friend of mine was working on a project to make that a little less painless: http://github.com/dkellum/hashdot
18:00	technomancy	kinda rough around the edges in terms of installation, but it is worlds better than the "java" launcher
18:00	ieure	I think the best thing about Clojure is that it leverages everything in the JDK. As opposed to it’s downside, which is that it leverages the JDK.
18:00	Chousuke	heh
18:00	ieure	Seriously, I hate Java.
18:00	ieure	technomancy, 404.
18:01	technomancy	ieure: right; that should be https://github.com/dekellum/hashdot/tree
18:01	ieure	Thanks.
18:01	technomancy	it's a command-line tool that's written by someone who's actually used a terminal before! amazing.
18:02	technomancy	<insert rant about single-dash-full-word arguments />
18:03	technomancy	the cool thing about hashdot is that you install it once and symlink it to clj, jruby, rhino, etc; and it loads different property profiles based on what symlink it was invoked with.
18:10	ieure	hashdot looks nice, thought it doesn’t solve the .jar issue.
18:10	technomancy	nope. =\
18:10	technomancy	it's focused more on server-side JVM than distribution
19:00	krumholt_	i have this list '(a a a b b c c c c d a a) and i want => ((a 3) (b 2) (c 4) (d 1) (a 2)) anyone knows a clever way to do this?
19:01	technomancy	are you sure you want a list and not a map as the return value?
19:01	krumholt_	they have to be ordered
19:02	krumholt_	i dont want to know how many a's where in the list. i want to know how many where there in a row
19:03	krumholt_	like (a a a b a a a) => ((a 3) (b 1) (a 3)) the order of the elements is still there it is just mor compact
19:08	replaca	krumholt_: I would write a little func that used (take-while #(= (first foo) %) foo), count, drop and loop/recur to build the list
19:08	replaca	krumholt_: more clojure-y to build the result as a vec (and it lets you use cnj and get the right order)
19:09	replaca	but there might be a better way
19:10	krumholt_	a take-while looks usefull thanks
20:07	technomancy	ieure: I'm not using the http client for authenticated requests, but if you're seeing arguments ignored I will try to fix that.
20:08	ieure	technomancy, Your HTTP client worked fine. The contrib one ignored the :headers I gave it.
20:08	technomancy	oh gotcha
20:09	technomancy	yeah, I've found it's a bad idea to implement features I don't use, but I'm happy to answer questions if you've got ideas for a patch.
20:09	ieure	I just had to generate the authtoken myself. And I guess there isn’t anything standard that does Base64 the way HTTP wants it.
20:09	ieure	technomancy, Maybe, I’m really not comfortable enough with Clojure to go hacking on it just yet.
20:10	ieure	From what I saw, I’d need some way to frobnicate the connection before sending the request.
20:11	ieure	Maybe a (with-connection) macro that I could call (request) inside of. Not rally sure.
20:12	technomancy	ieure: something like that is probably needed for connection pooling anyway
20:12	technomancy	but I haven't been doing much HTTP work these days
20:33	ieure	Hmm, the whole contrib.http.agent stuff seems to be pretty broken. This should work, right?
20:33	ieure	(use 'clojure.contrib.http.agent)
20:33	ieure	(let [a (http-agent "http://google.com")]
20:33	ieure	(response-body-str a))
20:33	ieure	It returns nil. Same for response-body-bytes.
20:33	ieure	But I can get the headers okay.
21:06	duncanm	because of Clojure, i started looking into Swing this weekend
21:07	duncanm	it's really not that bad, right? in fact, it's a pretty powerful toolkit
21:10	drewr	duncanm: it's tedious, but much more fun with clojure
21:10	duncanm	yeah, with Clojure, i think it's not a bad toolkit at all
21:37	uninverted	Does Clojure have any way to get the length of a sequence? I can't see anything in the docs.
21:42	mudphone	univerted: try count
22:07	weissj	is there a way to give a function param a default value, other than just adding a new section without that param, and just calling the first section with the default value?
22:08	weissj	ie like (defn x ([y z] (str y z)) ([y] (x "yo")))
22:09	weissj	that would give z a default of "yo"
22:17	drewr	weissj: defnk in clojure.contrib.def gives you keyword args that have default values
22:30	duncanm	have any of you looked into JavaFX? i'm confused as to what it is
22:30	duncanm	i thought it's a new language with a set of Java libraries (built on top of Swing)
22:31	duncanm	but i can't find any resource on using the JavaFX libraries using something other than JavaFX script
22:31	cemerick	weissj: using map destructuring with a default value is more idiomatic, and doesn't require an external lib
22:32	cemerick	duncanm: sun hasn't followed through on their prior statements about supporting using javafx libs from other languages
22:33	cemerick	they're supposedly going to open things up eventually, but it's in the air at this point
22:34	duncanm	ahh
22:34	duncanm	but it's still possible, right? it's just yet another jar
22:48	cemerick	yeah, I've read of people figuring some stuff out (using jruby, I think?). A lot of the API is reflection-driven though, so it's not as straightforward as running javap and backing into things.
23:13	Jomyoot	Do you guys prefer light on dark or dark on light background?
23:14	skalnik	Depends on what
23:14	skalnik	Code I like light on dark, everything else, dark on light
23:19	scottj	Jomyoot: dark on light because I have a bright work environment and I like all my windows to be consistent, and its much easier ot have everything light than everything dark (webpages don't convert well)
23:24	Chouser	agriffis (who's apparently not here at the moment) has a script which switches all his xterms and gvim windows between light-on-dark and vice-versa based on the time of day.
23:30	duncanm	Chouser: that's cute
23:44	fsm	Hello everyone, I am back with my double primitive performance issue
23:45	fsm	I have a test case if anyone wants to look http://solardriftwood.com/testdouble.clj
23:45	fsm	This test tries various methods of storing and accessing arrays of doubles
23:45	fsm	But, looking in the profiler, all the math is done using Numbers.add instead of native ops, no matter what
23:46	fsm	Am I doing something wrong?
23:47	hiredman	fsm: have you set warn-on-reflection?
23:47	hiredman	clojurebot: performance
23:47	clojurebot	Gabh mo leithscéal?
23:47	fsm	Yes, I have set warn-on-reflection, there is no reflection
23:47	hiredman	bah
23:47	hiredman	clojurebot: you worthless bag of bones
23:47	clojurebot	I don't understand.
23:48	fsm	I am quite perplexed about why nth and [] is as fast as using native double arrays
23:48	fsm	and I am a bit perplexed why none of my math is done with primitives
23:48	fsm	I have been through the whole range of tips on the java_interop page
23:49	fsm	Clojure is great but having virtual method calls inside my arithmetic is slowing down my raytracer alot
23:49	hiredman	fsm: I am fairly certain (+ (vxfn vectPrim) 1.0) should result in a reflecton warning
23:49	fsm	Sample image here btw: http://solardriftwood.com/aa.png
23:50	fsm	I just ran again with warn-on-reflection, no reflection occurs
23:50	rhickey	fsm: you've read this carefully? http://clojure.org/java_interop#primitives
23:51	hiredman	fsm: reflection warnings do not happen when you run code
23:51	rhickey	and: http://clojure.org/java_interop#optimization
23:51	fsm	Yes, I believe I have tried every trick in the book
23:51	hiredman	the happen at compile time, when you paste code into the repl for example
23:51	fsm	My test case is here: http://solardriftwood.com/testdouble.clj
23:52	fsm	I have seen refl warnings before in my other code, no refl warnings in this code
23:52	fsm	My issue is that Number.ops is being called for what should be primitive arithmetic by my understanding
23:52	rhickey	nothing in the optimization section says use aset-double, it's slow
23:52	fsm	aset-double is only used three times, outside the performance loops
23:53	fsm	I have also tried into-array, no difference
23:53	rhickey	"aget/aset are overloaded for arrays of primitives"
23:53	fsm	I am enjoying Clojure greatly, I am just a bit perplexed on this issue
23:53	fsm	That is, if I have a macro that uses aget, why is Number.ops used on the resulting double, instead of native operator +
23:54	fsm	In the profiler, I can see that Number.ops is called for every single arithmetic in that test case
23:55	fsm	Basically, for my raytracer I am seeking the most efficient way to represent vectors of 3 doubles (x, y, z)
23:55	rhickey	you'v e built all of this macro stuff - you shouldn't macro-ize until you have a hand-written thing you want to generate
23:55	fsm	I did that to test the performance of macro vs function
23:55	fsm	I found that macro-izing actually caused about 30% speed drop in my raytracer
23:56	fsm	Nonetheless, I wish to get rid of all these Number.ops
23:56	fsm	The test case compares macro and function versions, but either way, Number.ops is used
23:57	fsm	I have looked at the implementation and found that aget turns into a static method that has the body return xs[i]
23:57	fsm	Is the return value of aget boxed?
23:58	hiredman	fsm: first line of http://clojure.org/java_interop#optimization
23:58	fsm	Yes, does that apply to return values as well? That is the thing I couldn't work out myself.
23:59	rhickey	you need to use primitive locals, as described in those sections, and primitive arrays, and the primitive array constructors double-array etc