#clojure – 2011-10-15

2011-10-15

00:02	amalloy	ThreeCups: it may help to understand that use is a combination of require/refer
00:03	ibdknox	,(doc refer)
00:03	clojurebot	"([ns-sym & filters]); refers to all public vars of ns, subject to filters. filters can include at most one each of: :exclude list-of-symbols :only list-of-symbols :rename map-of-fromsymbol-tosymbol For each public interned var in the namespace named by the symbol, adds a mapping from the name of the var to the var to the current namespace. Throws an exception if name is already mapped to somethin...
00:03	amalloy	require causes code to be loaded, and refer creates aliases in your current namespace to already-loaded symbols
00:03	ibdknox	wow
00:03	ibdknox	self-referential
00:03	napping	carllerche: The name just sounded like something for making xss attacks
00:03	carllerche	heh… it's the opposite :P
00:16	ThreeCups	ibdknox, amalloy: thanks. I'm slowly wrapping my head around this :)
01:21	bsteuber	is it possible to execute js for simulating a button click with clj-http?
01:26	jedahu	strange clojurescript behaviour
01:26	jedahu	(- 1) ; => 1
01:26	clojurebot	0
01:26	jedahu	the defn of - in cljs.core is correct
01:28	napping	bsteuber: I've seen some java libraries that could
01:28	jedahu	(cljs.core/- 1) ; => 1
01:29	ibdknox	the math ops are inlined now
01:29	jedahu	ibdknox: I am using v0.0-838-g567be71
01:29	jedahu	just pulled a minute ago
01:30	napping	HttpClient (which clj-http wraps) claims not to: http://hc.apache.org/httpcomponents-client-ga/primer.html
01:30	ibdknox	jedahu: https://github.com/clojure/clojurescript/blob/master/src/clj/cljs/core.clj#L57
01:30	bsteuber	napping: until now I just found selenium but it controls an actual browser and thus might be slow for data mining
01:32	bsteuber	thanks anyways - gotta leave..
01:32	napping	I think it was over 10 years ago, but I remember something that included a dom and a javascript interpreter (is Rhino that old?)
01:32	jedahu	ibdknox: thanks. in that case, is there a negation function/macro lying around?
01:32	napping	Xerces and Rhino, IIRC
01:33	jedahu	or can - be fixed to behave like cljs.core/- ?
01:33	ibdknox	jedahu: (- 0 1)
01:33	ibdknox	,(- 3)
01:33	clojurebot	-3
01:34	ibdknox	,(- 0 3)
01:34	clojurebot	-3
01:34	jedahu	ibdknox: fair enough
01:34	napping	Ah, HtmlUnit
01:34	napping	is there any way to leave a message?
01:40	amalloy	napping: in irc, you mean?
01:40	napping	on clojurebot, I was thinking
01:40	amalloy	$mail napping lazybot will take messages for you
01:40	lazybot	Message saved.
01:41	napping	$mail bsteuber The library was HtmlUnit. It seems to still be active
01:41	lazybot	Message saved.
02:02	Raynes	$mail napping I wouldn't rely on that though. lazybot isn't very aggressive and will only NOTICE people when they have messages. If they don't have NOTICEs set up to direct to whatever channel they're in, it may be a while before they see it or they may never see it at all.
02:02	lazybot	Message saved.
02:03	Raynes	amalloy: Now, let's see if he ever actually gets that message. Should be fun.
02:04	scottj	lame on github's search page they have languages split into popular and everything else and common lisp and scheme are both in the popular section and clojure is in the everything else despite clojure having a higher popularity ranking on github
02:05	Raynes	scottj: I hate how far down I have to scroll in the dropdown in gists.
02:05	amalloy	every pixel an insult
02:06	ibdknox	seriously.
02:06	ibdknox	we should petition
02:06	scottj	Raynes: looks like you can type Clojure in the drop down
02:08	Raynes	scottj: Still, it's blasphemy.
02:53	FrankL	How can I update the clojure version counterclockwise uses to 1.3.0?
02:54	FrankL	I tried googling, but couldn't really find a guide
02:55	mikera	FrankL works for me just by including the Clojure 1.3 jar in the build path rather than the 1.2 version (I do this with Maven usually, but I think it works by just editing the standard build path as well)
02:56	FrankL	thanks mikera, i'll try that
03:01	FrankL	hm, just changing the build path and refreshing the project doesn't work
03:02	FrankL	although i haven't changed the clojure-src.jar
03:03	amalloy	chouser: i just looked at the new, 1.3 impl of doc. i can't see a reason for not quoting the first half of the if-let - it means that if i did, say, (defn print-&-doc [] (doc &)), that would print the docs once at compile time instead of every time the function is called
03:05	FrankL	ah, nevermind, i only changed the src attachment the first time, now it works
03:05	FrankL	thanks mikera!
03:05	mikera	np! glad you got it to work, these things can be fiddly sometimes.......
03:15	mikera	anyone had luck getting Pallet to work with Clojure 1.3?
03:16	Raynes	dakrone: You wouldn't happen to be around, would you?
03:37	todun	When defining my function using defn, I want to pass a list as a parameter. The syntax seems to be to use square brackets for parameters. However the syntax for lists are parentheses(circular brackets). do I do this: defn function-name [a-list] ...) or do I do defn function-name2 (another-list) ...)? I'm new to clojure so sorry if this sounds silly.
03:38	mikera	todun just do (defn my-fun [listname] .....)
03:38	brehaut	todun: the arguments vector is independant of the types of the variables you pass
03:38	todun	When I call my function in the REPL, do I do (function-name [1 2 3]) or do I do (function-name2 (1 2 3 4)) ?
03:39	mikera	the former is best
03:39	todun	mikera: brehaut ok. that is a bit confusing. I see that there are seqs, lists, vectors, sets. All with different syntaxes for defining them.
03:39	mikera	(1 2 3 4) won't work since it will try to apply "1" as a function to the arguments 2, 3 and 4 which is probably not what you want....
03:40	mikera	you can do (my-fun '(1 2 3 4)) though if you like, which will pass a list rather than a vector
03:40	brehaut	todun: you almost never define lists in your code; they are more frequently used at the macro level
03:40	todun	mikera: so parens are like function scopes all the time in clojure?
03:40	brehaut	todun: no, they are sometimes macros or special forms
03:41	todun	brehaut: is clojure doing type inferencing then? if so, how does it infer type if its structure is not specified?
03:41	brehaut	todun: and they represent many list like things when printed to the repl (seqs, cons, lists etc)
03:41	brehaut	todun: it does type inference for purposes of avoiding reflective calls in interop but its a dynamically typed language
03:43	amalloy	todun: i think you are barking up the wrong tree. (foo bar) always indicates "call the function foo with argument bar", unless (a) foo is a macro itself, or (b) that list is surrounded by a macro or special form that dictates otherwise
03:43	todun	brehaut: I just read up on macros and it seems they're like interfaces in java or python's modules.
03:43	brehaut	,(map (juxt class pr-str) [(list 1 2 3) (map inc [0 1 2]) (cons 1 ())])
03:43	clojurebot	([clojure.lang.PersistentList "(1 2 3)"] [clojure.lang.LazySeq "(1 2 3)"] [clojure.lang.Cons "(1)"])
03:43	amalloy	sorry, they are nothing like interfaces or modules though
03:43	brehaut	todun: not at all
03:43	brehaut	todun: macros allow you to effectively write compiler plugins
03:44	brehaut	todun: namespaces are roughly analogous to pythons modules and protocols are roughly analogous (but way better) than javas interfaces
03:44	todun	amalloy: brehaut uhm. ok.
03:44	todun	brehaut: I've not seen protocols yet.
03:45	todun	not sure if I've seen macros.
03:45	amalloy	macros are a concept that no other languages really have
03:45	brehaut	todun: you dont need them yet
03:45	todun	brehaut: ok.
03:45	amalloy	(no other non-lisps, that is)
03:45	todun	I'll keep writing my recursive methods and come back if I fall into a conceptual rut...
03:46	todun	, '(1 2 3)
03:46	clojurebot	(1 2 3)
03:46	todun	cool!
03:46	amalloy	todun: brehaut's summarization of macros as compiler plugins is good, and a useful way to think of things. you're using macros all the time, you just don't know about it
03:46	brehaut	you should be trying to learn how _not_ to be writing recursive methods
03:46	todun	amalloy: ok.
03:46	todun	brehaut: how so?
03:46	brehaut	todun: functional programming includes lots of abstractions that take care of the recursion for you; eg, map reduce filter etc
03:46	brehaut	reduce is a particular recursive pattern
03:47	amalloy	&(if-let [x 1] (inc x) :no-such-thing)
03:47	lazybot	⇒ 2
03:47	amalloy	&(macroexpand '(if-let [x 1] (inc x) :no-such-thing))
03:47	lazybot	⇒ (let* [temp__3586__auto__ 1] (if temp__3586__auto__ (clojure.core/let [x temp__3586__auto__] (inc x)) :no-such-thing))
03:47	todun	amalloy woah.
03:48	todun	amalloy: I've just done some reading on TOC, lazy seq, regular recursion.
03:48	brehaut	tadah!
03:48	mikera	:-) todun you should probably ignore that stuff for now!
03:48	amalloy	todun: if-let is a pre-built "plugin" for the compiler that turns "function calls" that start with 'if-let into slightly more useful code
03:48	todun	amalloy: trying to implement a bunch of problems using all these techniques.
03:48	todun	mikera: ok.
03:49	amalloy	heh, well. using every technique all at once will just lead to a soupy mess, probably
03:49	todun	brehaut: Arthur C Clarke comes to mind here...
03:49	mikera	not that it's not useful, but there is a lot to take in at once... took me a couple of months before I got comfortable with macros....
03:50	todun	amalloy: how does let work? also, how does letfn work? I couldn't understand what it was quite doing in the examples I looked at.
03:50	mikera	,(let [x 10] (* x x ))
03:50	clojurebot	100
03:50	todun	mikera: ok. I'll avoid it for now. but I have a feeling I'll need it when I reach concurrency.
03:51	brehaut	todun: have you joined 4clojure?
03:51	todun	brehaut: nope. I can join?
03:51	mikera	yeah you will need it, but i'd suggest getting the basics nailed first, especially the stndard syntax, higher order functions etc.
03:51	mikera	4Clojrue is a great way to start!
03:52	todun	,(reverse (1 2 3 4))
03:52	clojurebot	#<ClassCastException java.lang.ClassCastException: java.lang.Long cannot be cast to clojure.lang.IFn>
03:52	amalloy	todun: www.4clojure.com
03:52	mikera	,(reverse '(1 2 3 4))
03:52	clojurebot	(4 3 2 1)
03:52	todun	,(reverse [ 1 2 3 4])
03:52	clojurebot	(4 3 2 1)
03:52	mikera	you need the ' to make a list......
03:52	todun	,(reverse [1 2 3 [1 2 3]))
03:52	clojurebot	#<ExecutionException java.util.concurrent.ExecutionException: java.lang.RuntimeException: Unmatched delimiter: )>
03:53	todun	why does the second one give an error?
03:53	mikera	unmatched brackets, you want:
03:53	amalloy	([[])) doesn't balance
03:53	mikera	'(reverse [1 2 3 [1 2 3]])
03:53	mikera	,(reverse [1 2 3 [1 2 3]])
03:54	clojurebot	([1 2 3] 3 2 1)
03:54	brehaut	also, if you are reversing a vector (rather than a sequence or list) you might want rseq instead of reverse
03:55	todun	brehaut: that's why I asked my earlier questions. I want a list specifically.
03:56	brehaut	todun: why? its not common to want a list specifically in clojure
03:56	todun	, '(1 2 3 (1 2 3))
03:56	clojurebot	(1 2 3 (1 2 3))
03:56	todun	brehaut: ok.
03:57	todun	amalloy: I have corresponding brackets, why doesn't it balance?
03:57	Raynes	[[] <-- Note the lack of second ].
03:57	amalloy	your, uh...your statement is untrue
03:58	todun	Raynes: amalloy yes. thanks.
03:59	todun	,(reverse '(1 2 3 '(1 2 3)))
03:59	clojurebot	((quote (1 2 3)) 3 2 1)
03:59	todun	I was warned about clojure and its brackets.
04:00	brehaut	‽
04:00	clojurebot	Huh?
04:00	brehaut	you prefer to type more of them?
04:00	brehaut	or you'd prefer only parens?
04:01	todun	brehaut: indifferent.
04:02	mikera	Clojure usage of brackets is actually very logical, it's just different from C-like languages. I usually need less in Clojure than I do in Java for the same code.
04:03	todun	mikera: I'm yet to find that out or not.
04:03	brehaut	todun, python's equivalent of your expression above is [1,2,3,[4,5,6]][::-1] which is equally brackety, and has additional punctuation not needed in clojure
04:05	todun	brehaut: I'm not decrying clojure. just saying that I've really not done much in it to say one way or another. In fact, these will be my first non-example clojure code I'll be writing.
04:05	todun	:)
04:09	mikera	http://www.infoq.com/presentations/Clojure-in-the-Field is a good video for some of this stuff
04:11	todun	mikera: thanks.
04:13	mikera	other things is 4Clojure (http://www.4clojure.com/), well worth doing 20-30 of these problems. a nice bonus is that you get to see how other people solved the probelms too......
04:14	brehaut	mikera: or 80-90…
04:14	brehaut	i dont have a problem. i could quit whenever i want
04:15	amalloy	brehaut: i have a stash of four problems i haven't solved yet, for when the cravings get really bad
04:15	brehaut	amalloy: ive got mostly involved or mathy ones left
04:16	amalloy	well, me too. i actually left them unsolved cause i wasn't really interested :P
04:16	brehaut	hah :)
04:16	brehaut	we cant all be chouser i guess
04:21	brehaut	102 has taught me i dont know the string ns at all well enough
04:21	todun	is there a way to kill the currently running command in the REPL without quitting the REPL?
04:22	brehaut	it depends
04:22	brehaut	what repl ?
04:23	todun	lein repl
04:23	brehaut	i think you might be out of luck
04:25	todun	brehaut: ok. thanks.
04:27	amalloy	brehaut: wait till you get to 117. some of the solutions will make you wonder if the authors have ever seen a library that isn't about strings
04:28	brehaut	amalloy: that looks like a PITA
04:28	brehaut	and i am fearful of how you would do that as a strings problem
04:28	amalloy	yeah, my solution is pretty awful
04:28	amalloy	amcnamara has a good solution that makes sense, but chouser and youz do some WEIRD string stuff i can't understand at all
04:28	brehaut	haha
04:29	brehaut	i bashed out a game of life solution last night
04:29	brehaut	i went and looked at some of the solutions
04:30	brehaut	mine is the 4yo with crayons version
04:30	amalloy	laugh
04:30	brehaut	all the basic elements are there, but its really crude
04:31	brehaut	youz solution confuses the crap out of me
04:33	amalloy	(- -1 w) is something that almost seems like it can't make sense
04:34	brehaut	hah yeah
04:34	brehaut	its not an idiomatic construction thats for sure ;)
04:35	Raynes	youz is God.
04:42	amalloy	he's more like loki. a Trickster
04:43	brehaut	haha excellent
05:06	archaic	i rebound ; to 'paredit-open-paren .. best decision ever
05:08	amalloy	archaic: so you can't write any comments? i prefer swapping the "shift-ness" of numbers and symbols; 9 isn't such a hard key to reach for, and i can still pepper my everyday speech with semicolons
05:10	archaic	comments is C-; now since i use alot less than paren
05:10	amalloy	the important thing is you're customizing, though. don't stick with inferior tools, and don't listen to strangers like me who tell you your setup is silly
05:12	amalloy	and there's a nice parallel with java/c which is covered with semicolons
05:25	todun	I'm getting errors I can't quite understand when I do this http://pastebin.com/TiAg30gZ
05:26	raek	todun: (defn z n ...) --> (defn z [n] ...)
05:26	todun	raek: but n is just a number, does it need [n} ?
05:26	raek	but the cond clauses don't make much sense
05:27	todun	*[n]
05:27	raek	todun: yes, a function can have more than one argument
05:27	todun	raek: uhm ok. thanks.
05:28	raek	just like you need the ()s in java: public static void main(String args[]) ...
05:28	todun	raek: that does make sense. thanks.
05:28	raek	todun: cond takes alternating conditions and expressions. you have 3 forms on the middle line and only one on the last
05:29	todun	raek: uhm. I don't quite follow.
05:29	raek	if n is even, is cond going to return z or (/ n 2)?
05:30	todun	raek: alternating conditions as in conditions that don't match?
05:30	todun	raek: oh. so it's not sequential?
05:30	todun	raek: meaning it does not do the first, second then last?
05:31	raek	it is sequential. lets say you have (cond c1 e2 c2 c2 c3 e3 :else e4)
05:31	raek	if it check c1 first. if it's true, cond will evaluate and return e2
05:31	raek	*it will check
05:31	raek	if c1 was false, c2 is checked
05:32	raek	if c2 is true, then e2 is evaluated and returned
05:32	raek	so cond is like "if (..) .. else if (..) .. else if (..) .. else"
05:33	raek	what I
05:33	raek	I'm confused about is "z (/ n 2)"
05:33	raek	if (even? n) returns true, then z is evaluated and returned
05:34	raek	if (even? n) returns false, (/ n 2) is the new condition to check
05:34	raek	which doesn't make much sense, since it's a number
05:34	raek	did you mean (z (/ n 2))
05:34	todun	raek: ok.
05:35	todun	raek: if I have a function.
05:36	todun	a function to me is when I use defn, and I call it within its definition(recursion), do I put a space between the function name and the arguments?
05:36	raek	todun: a function call is always wrapped in a pair of parens
05:36	todun	what I did was call z(/ n 2) is this illegal?
05:36	raek	yes, that's not clojure syntax
05:37	todun	raek: I see. the example I was following for cond didn't have a function call but just literals. I projected that case to function calls.
05:37	todun	raek: so that's why I get a strange result for that case. thanks.
05:37	raek	if you for instance say (+ 2 z (/ n 2)), that would mean "take the sum of 2, the function z, and the expression (/ n 2)". i.e. z is not called
05:38	raek	(+ 2 (z (/ n 2))) means "take the sum of 2 and what you get when you call z with (/ n 2)"
05:39	todun	raek: ok.
05:39	raek	todun: http://pastebin.com/LYS2XBYV
05:40	raek	so in clojure, the parenthesis are never optional
05:41	todun	raek: I get an error when I try this http://pastebin.com/EBCevmWi
05:41	todun	illegalArgsExcetion.
05:41	todun	thanks for the least.
05:41	todun	*list
05:41	archaic	(+ 1 2 3)
05:41	clojurebot	suffusion of yellow
05:41	raek	todun: you didn't fix the (defn z [n] ...) problem
05:42	raek	and the :else line has an error
05:43	todun	raek: sorry I did. I just didn't change the pastebin right.
05:43	todun	let me repost
05:43	raek	what you should have is (cond c1 e2 c2 e2 :else e3)
05:43	todun	raek: ok.
05:43	raek	but what you have is (cond c1 e1 c2 e2 (:else e3))
05:44	raek	sorry, it should be "c1 e1" in the first line
05:44	todun	oh. so :else is a function?
05:44	todun	I thought it was a keyword?
05:44	raek	no, it's a keyword
05:44	raek	which is a value
05:45	raek	:else evaluates to :else, since keywords are self-evaluating (like numbers)
05:45	archaic	is (dorun (map ..)) idiomatic to force a map for side-effects?
05:45	todun	http://pastebin.com/kfxN5inh
05:45	raek	and the rule for conditions in clojure is that false and nil are falsy, and everything else (including keywords) are truthy
05:46	amalloy	clojurebot: who taught you (+ 1 2 3) is suffusion of yellow, anyway?
05:46	raek	archaic: either that or (doseq ...)
05:46	clojurebot	I don't understand.
05:46	todun	raek: uhm. ok.
05:46	raek	so :else is a condition that is always true
05:46	todun	raek: like a default value.
05:47	raek	you could have written true instead of :else there, (as you would do in common lisp) but it's ideomatic to use :else in clojure
05:47	todun	or a java pass or perhaps continue
05:47	raek	todun: yes, it's the last catch-all case
05:48	raek	todun: but the parentheses around :else and (z (+ (* 3 n))) shouldn't be there
05:49	raek	those parentheses will make that whole thing the condition and then there's no expression for it (since the contents of 'cond' will now be an odd number of forms)
05:49	todun	but I thought it ought to be around functions, like z?
05:50	raek	but you don't want to unconditionally call :else with the result of (z (+ (* 3 n))), right?
05:51	raek	'cond' is a special form, so it doesn't work like a function call
05:51	raek	it's a macro that gets translated into a bunch of ifs
05:51	todun	raek: uhm ok. et me do some debbuging.
05:52	raek	(cond c1 e1 c2 e2 c3 e3) --> (if c1 e1 (if c2 e2 (if c3 e3 nil)))
05:52	raek	the if special form has the syntax (if <condition> <then expression> <else expression>)
05:53	raek	todun: this is what you function should look like: http://pastebin.com/94trLBhS
05:54	raek	note that in clojure whitespace and newlines are not part of the syntax
05:54	raek	only the parentheses determine the structure of the code
06:18	todun	raek: uhm. ok.
06:20	todun	raek: instead of using z, I can usee recur, so it does TOC?
06:30	todun	is there a way to check for duplicates?
06:31	llasram	Duplicate which?
06:32	archaic	there are functions frequencies and distinct that may do what you need
06:35	todun	llasram: (duplicates? '(1 1 2 2 3))
06:36	todun	archaic: ok. let me read up on those.
07:11	todun	what is the value of an empty list?
07:11	todun	or rather, how to test if a list is empty?
07:11	opqdonut	,(doc empty?)
07:11	clojurebot	"([coll]); Returns true if coll has no items - same as (not (seq coll)). Please use the idiom (seq x) rather than (not (empty? x))"
07:11	opqdonut	also, you can compare to '()
07:12	opqdonut	which is slightly different
07:16	todun	opqdonut: thanks.
07:16	todun	opqdonut: I tried '() but got an error.
07:16	todun	opqdonut: sorry. take that back.
07:16	todun	I was trying ()?
07:25	Borkdude	I'm trying to push to heroku, how do I get a 'local' jar up there?
07:25	Borkdude	Question was also asked on the Clojure google group: http://groups.google.com/group/clojure/browse_thread/thread/4045276f24444a69
07:32	todun	how to find the head of a list in clojure? is there like a term called head ? also is the only way to find the nest element (head (next a-list))? thanks.
07:33	archaic_	(first [1 2 3])
07:33	archaic	(rest [1 2 3])
07:33	todun	archaic_: thanks.
07:34	todun	,(first [1 2 3])
07:34	clojurebot	1
07:45	daniel__	thats a vector...
07:45	daniel__	,(peek '(1 2 3))
07:46	clojurebot	1
07:46	daniel__	for a list
07:48	todun	,(if (= (compare (first [1 2 3]) (first (rest [ 1 2 3])) ) 0) (remove (first [1 2 3]))
07:48	clojurebot	#<ExecutionException java.util.concurrent.ExecutionException: java.lang.RuntimeException: EOF while reading>
07:48	todun	why is this wrong?
07:49	todun	I thought if takes only condition & expression.
07:49	todun	or no?
07:51	raek	if takes one condition and two expressions
07:51	raek	and remove takes a function and a collection
07:51	raek	,(remove even? [0 1 2 3 4])
07:52	clojurebot	(1 3)
07:52	raek	and you can use (= x y) instead of (= (compare x y) 0)
07:53	todun	raek: ok. let me refine it. thanks.
07:58	todun	reak: if I want to know the result of remove in the following, how do I get it?
07:59	todun	,(if (= (first [1 2 3]) (first (rest [ 1 2 3])) ) (remove (first [1 2 3])))
07:59	clojurebot	nil
08:04	raek	todun: that call to remove doesn't make any sense
08:04	todun	can I do assignment in clojure?
08:04	todun	raek: no sense in what way?
08:04	raek	well, you usually don't do it for computations
08:04	raek	(assignments)
08:05	raek	you can use let, which introduces a name for a value (but doen't allow you to reassign it)
08:05	raek	,(doc remove)
08:05	clojurebot	"([pred coll]); Returns a lazy sequence of the items in coll for which (pred item) returns false. pred must be free of side-effects."
08:05	raek	remove take two arguments, and you only pass it one
08:05	raek	also, remove does not do what I think you think it does
08:06	raek	if you want a new sequence where the first element is missing, use rest
08:06	todun	raek: uhm. ok. let me rework it.
08:06	raek	todun: also, that code snippet returns nil since the condition is false
08:07	raek	(if condition then-expr) = (if condition then-expr nil)
08:07	todun	raek: ok.
08:07	raek	the else branch defaults to a constant nil if you don't supply it
08:08	raek	todun: it's better to think of functions as thing that receives some values and make a new value, rather than a thing that changes stuff
08:09	raek	you can think of the expression (rest coll) as a name for "coll, but without the first element"
08:09	todun	,(if (= (first [1 1 3]) (first (rest [ 1 1 3])) ) (remove (first [1 1 3]) [1 1 3]) )
08:09	clojurebot	#<ExecutionException java.util.concurrent.ExecutionException: java.lang.ClassCastException: java.lang.Long cannot be cast to clojure.lang.IFn>
08:10	raek	todun: remove does not take an element as the first argument. it takes a predicate
08:10	todun	raek: ha. uhm. ok. I misread that then. sorry.
08:10	raek	(let [coll [1 1 3], x (first coll)] (remove (fn [element] (= element x)) coll))
08:10	raek	,(let [coll [1 1 3], x (first coll)] (remove (fn [element] (= element x)) coll))
08:10	clojurebot	(3)
08:11	raek	you can write that predicate as #(= % x) or even #{x}
08:11	todun	raek: I see.
08:12	todun	raek: if I want to yield the list after the remove, how do I do so?
08:13	raek	remove yields the list
08:13	todun	in particular, the output is (3) but I expect it to be (1 3)
08:13	raek	todun: but filter removes all occurances where the predicate matches
08:13	todun	I dont use filter.
08:14	raek	todun: if you just want to get a list without the first element (whatever it is) use "rest"
08:14	raek	todun: sorry, remove
08:14	todun	raek: ok. let me try that.
08:14	raek	filter does the opposite (keep the elements where the predicate return true)
08:14	raek	,(rest [1 2 3 4])
08:14	clojurebot	(2 3 4)
08:15	todun	raek: ha yes. the imperative mind-set trap was not letting me see that optimization. thanks.
08:16	raek	in functional languages, the expression is the building block, not the statement
08:16	raek	and you describe values, rather than side-effects
08:17	todun	raek: how do I use let to ensure I'm working with the modified list?
08:17	raek	if returns a value too (namely the value of either the then-expression or the else-expression, depending on the value of the condition)
08:17	raek	,(let [rest-of-the-list (rest [1 2 3 4])] .... use rest-of-the-list-here ...)
08:17	clojurebot	#<CompilerException java.lang.RuntimeException: Unable to resolve symbol: .... in this context, compiling:(NO_SOURCE_PATH:0)>
08:18	raek	todun: you just give a name to the result of the if or the rest call or whatever and then use that name in another expression
08:19	raek	,(let [foo (rest [1 2 3 4])] (reverse foo))
08:19	clojurebot	(4 3 2)
08:19	raek	,(reverse (rest [1 2 3 4]))
08:19	clojurebot	(4 3 2)
08:20	todun	raek: is this functional, this internal side-effecting that I'm proposing?
08:20	raek	what side-effect?
08:20	raek	let is side-effect free
08:20	todun	raek: giving names and passing them like you did.
08:21	raek	to give names to values is indeed functional
08:21	todun	raek: uhm. ok.
08:21	raek	you cannot change the values themselves in clojure
08:21	raek	so [1 2 3] will always be [1 2 3]
08:21	raek	(let [original [1 2 3], changed (rest original)] ...)
08:22	raek	inside the let, original still refers to [1 2 3] and changed refers to (2 3)
08:23	raek	so the standard libary functions don't actually change collections, they return new variants of the old values
08:23	raek	and the old values are still available
08:23	todun	raek: um. ok.
08:23	todun	, (if (= (first (name [1 1 3])) (first (rest name)) ) (rest name) )
08:23	clojurebot	#<ClassCastException java.lang.ClassCastException: clojure.lang.PersistentVector cannot be cast to clojure.lang.Named>
08:24	todun	do I have to use the square brackets?
08:24	raek	what are you doing with the 'name' function here?
08:24	raek	( ) means call a function
08:24	todun	making it [1 1 3]
08:24	raek	(name [1 1 3]) <-- what do you want this to do?
08:25	todun	I want it to be called by first, rest
08:25	todun	(if (= (first name)) (first (rest name)) ) (rest name) )
08:25	todun	name = [1 2 3]
08:25	raek	then you need to let it first
08:26	raek	"name" is also a function in the standard library
08:26	raek	,(let [name [1 1 3]] (if (= (first name) (first (rest name))) (rest name) "something here"))
08:26	clojurebot	(1 3)
08:28	todun	raek: ok. thank.
08:29	raek	also "let" is a special form, so (let ...) is not a function call
08:29	todun	raek: special form?
08:29	raek	it's hard-coded in the compiler
08:30	raek	(let ...) has special rules for how the "..." is interpreted
08:31	raek	so you don
08:32	raek	't evaluate the [name [1 1 3]] thing. the compiler looks at it and emits code that stores the [1 1 3] gives it a name
08:32	todun	raek: I see. just like the way TOC works.
08:33	todun	*TCO
08:37	todun	when I write this function to remove duplicates, I get the following error: not connected.
08:37	todun	http://pastebin.com/gk2ftEnP
08:38	todun	and it really an error per se, it is just that when I compile, I get the message splash at the bottom.
08:42	todun	I just realized it was referring to the swank server closing.
08:43	todun	When I try to reconnect, it keeps saying Connection closed. How is this possible?
08:43	todun	I thought the server was on my machine?
08:56	todun	I'm trying to do a reversal of a list. Even if the input is a list of lists, I want this nesting to be reversed. To this end, I use recur. But I don't think I have the logic right. Any comments, critiquing will be appreciated: http://pastebin.com/qYete3fb
09:39	Borkdude	Is it possible to push to heroku and let the server find jars based on pom.xml instead of project.clj?
09:40	Borkdude	For a Clojure project that is of course
09:53	Borkdude	Solved it through a push to clojars instead...
09:53	Borkdude	(the local but now not local anymore jar problem)
10:12	Borkdude	Is it possible to remove one of your groups and jars from clojars?
10:15	Borkdude	I want my jar to be in the group org.clojars.borkdude
10:15	Borkdude	so the group twitter-utils may be removed
10:17	Borkdude	(so I don't get in the way of someone else maybe one day wanting this name for a project)
10:55	kylpo	Woop woop! Finally have some time to start learning clojure this weekend :)
10:56	Borkdude	:-)
11:10	Borkdude	Hmm. What is supposed to be the outcome of (= (list) [])
11:12	Borkdude	I suppose lists and vectors are compared by elements, regardless of their type
11:15	floatboth	is lein install supposed to be like mvn install:install-file? because only the latter works properly :( I mean, with subprojects, I want to install them to the local repo and then lein deps on the main project should get them from it. But it only works after mvn, not lein install
11:16	Borkdude	have you tried lein localrepo?
11:16	Borkdude	https://github.com/kumarshantanu/lein-localrepo
11:17	floatboth	yeah
11:18	floatboth	it requires version and group/artifact id, it's kinda the same thing
11:18	floatboth	but looks like shell magic should work, like lein localrepo coords *.jar \| xargs lein localrepo install
11:18	Borkdude	floatboth: lein localrepo worked for me
11:18	floatboth	what's the point of lein install then?
11:19	Borkdude	dunno :)
11:23	tomoj	floatboth: does the bit after defproject for the project you ran `lein install` on match the group/artifactid?
11:25	floatboth	hmm
11:26	floatboth	looks like it's ok, "installing this.jar into ~/.m2/repository/group/artifact/this.jar"
11:29	floatboth	aaah, got it, lein sub was running it on the main project too before installing subprojects
12:00	duck1123	Generally speaking, if I get reflection warnings from a 3rd party library, then that's not really my problem, right? I'm trying to eliminate some of the reflection in my library and am wondering if I should be concerning myself with reflection in dependencies
12:09	Squeese	Ok, so reading pragmatics clojure book and "installing examples dependancies" with lein, it's spitting me maven error messages, supposedly not finding a package - where can I browse these packages and fix it? Is there a reposatiry somewhere?
12:10	dnolen	duck1123: the only problem is suboptimal interop perf from the dependency. You should let the lib author know.
12:13	Squeese	Yah, I sent mail, it's a beta release of the book
12:16	Squeese	oh well, http://build.clojure.org/ didnt make me any smarter, guess I'll butter up the patience :)
12:23	Squeese	Ok, so, I cant use (require 'deps) since the lein deps spits errors, can I modify "dep path" myself or maybe enter repl with a file loaded (wanting to try the examples)
12:25	daniel__	(ns evolve.core
12:25	daniel__	sry
12:25	daniel__	(nth (iterate #(doto (str ((fitness-fn target) %) " " (evolve % (fitness-fn target))) println) source) generations))
12:26	daniel__	can anyone tell me why this prints the fitness an increasing number of times for each iteration?
12:26	daniel__	it should be like: 100 blah; 200 blak; 300 blay; but instead its more like 100 blah; 100 200 blak; 100 200 300 blay;
12:30	robermann	daniel: I think the problem is using iterate
12:30	robermann	,(doc iterate)
12:31	clojurebot	"([f x]); Returns a lazy sequence of x, (f x), (f (f x)) etc. f must be free of side-effects"
12:31	Borkdude	Squeese: what book is this?
12:31	Squeese	Pragmatic programmers, Programming Clojure
12:33	daniel__	robermann: yeah, i see
12:33	daniel__	hmmm
12:34	robermann	(interleave [100 200] ["blah" "blak"])
12:34	robermann	,(interleave [100 200] ["blah" "blak"])
12:34	clojurebot	(100 "blah" 200 "blak")
12:39	robermann	or maybe you could use the repeatedly function
12:45	daniel__	robermann: maybe, ill have to think it through
12:46	daniel__	with repeatedly can i pass back what is returned as % like with iterate?
12:46	daniel__	in fact, nvm
12:46	daniel__	that defeats the point
12:47	daniel__	i might be able to work it in to my evolve method somehow as a side effect
12:47	duck1123	daniel__: can't you just map over the results and print them outside of the iterate? That way you're keeping that iterate fn side effect free?
12:49	daniel__	duck1123: im not sure i know what you mean
12:49	Squeese	ok, this.. is.. sexy.. why? I have no idea, its just.. sexy: (def sexy {:key "val"}) and then (:key sexy) or (sexy :key)
12:49	Squeese	is this general Lisp or Clojure specific?
12:50	duck1123	daniel__: instead of printing inside the iterate function, pass that seq to a mapping form that does the print. The laziness should still give you the progress you'r looking for
12:53	Bronsa	Squeese: afaik only clojure has it
12:53	Squeese	kk
12:54	robermann	daniel__: i think duck1123 is suggesting something like: (map #(println %) (range 1 10))
12:55	daniel__	the range being the iterate
12:55	daniel__	ok, think i get it
12:55	daniel__	let me try
12:55	robermann	yes
12:55	duck1123	robermann: exactly.
12:59	duck1123	Is there something I can pass to lein to put it into a strictly offline mode? If I'm maxing out my internet connection, then lein deps will take a long time to complete even if it's not apparently fetching snapshots.
13:01	daniel__	(nth (map #(doto (str ((fitness-fn target) %) " " %) println) (iterate #(evolve % (fitness-fn target)) source)) generations))
13:01	daniel__	works :) just looks a mess
13:02	duck1123	daniel__: that's when -> and ->> start to become your friend
13:04	daniel__	duck1123: i guess now would be a good time to learn what they do then :)
13:04	daniel__	and commit it to memory this time :p
13:05	robermann	daniel__ BTW, are you working on anything like http://www.pawfal.org/dave/blog/2011/10/evolving-musical-bytecode-3/ ?
13:06	duck1123	(-> (fitness-inner-fn) (iterate source) println (nth generations))
13:07	daniel__	no robermann, but it looks interesting
13:08	robermann	ok, i was just curious too, because recently I read http://www.pawfal.org/dave/blog/2011/10/evolving-musical-bytecode/ , where do exists a "fitness" function
13:09	daniel__	im just evolving a string into another string...an experiment to learn clojure really
13:10	duck1123	daniel__: are you converting the problem from your work in a different language, or is this something all new?
13:10	daniel__	duck1123: all new
13:11	daniel__	although it would be a lot simpler in another language at the moment
13:11	duck1123	I've been converting my large ruby application at work to clojure. It's difficult to translate an existing process sometimes
13:11	daniel__	i like clojure but i think you have to know it well to get the benefits
13:11	duck1123	Of course now I curse the days I have to work in Ruby
13:12	duck1123	It's really a progression of things clicking
13:12	daniel__	yep, i also came from ruby and i find it much easier to think of how to solve a problem in terms of ruby than clojure
13:12	daniel__	but its v early days
13:13	robermann	I translated stack traces/source code into music, just to stay on strange topics: www.codesounding.org
13:14	daniel__	i now think i want a map to map the map :p i want to add line numbers
13:14	duck1123	I find that I'm very much spoiled by Clojure's correct concurrency without having to think about it when working in Ruby. I'm always saying "Well, if this was in Clojure, I'd just ... and be done"
13:15	duck1123	->> puts the output of the previous form into the collection spot of the next form
13:15	duck1123	(->> coll (map fn1) (map fn2) (filter pred1) first)
13:16	daniel__	,(expmacro -->)
13:16	clojurebot	#<CompilerException java.lang.RuntimeException: Unable to resolve symbol: expmacro in this context, compiling:(NO_SOURCE_PATH:0)>
13:16	daniel__	,(expandmacro -->)
13:16	clojurebot	#<CompilerException java.lang.RuntimeException: Unable to resolve symbol: expandmacro in this context, compiling:(NO_SOURCE_PATH:0)>
13:17	duck1123	,(macroexpand '(->> coll (map fn1) (map fn2) (filter pred1) first))
13:17	clojurebot	(first (clojure.core/->> (clojure.core/->> (clojure.core/->> coll (map fn1)) (map fn2)) (filter pred1)))
13:17	duck1123	(first (filter pred1 (map fn2 (map fn1 coll))))
13:18	daniel__	ok
13:18	duck1123	I believe comping those 2 map fns may be better than 2 maps, but you get the idea
13:18	daniel__	btw, in this case is there an opposite of macroexpand? it should be fairly easy to take an expression and turn it into -->
13:19	daniel__	->>*
13:19	duck1123	well, turning things into a macro is really more for your benefit than the compiler.
13:20	duck1123	I'd love to see someone write something for clojure-mode though
13:20	daniel__	yes, but to make sure i dont make any mistakes moving things around
13:21	duck1123	unit tests :)
13:21	daniel__	:)
13:21	duck1123	anyway, I'm off. good luck
13:21	daniel__	alright, thanks
13:23	daniel__	robermann: interesting stuff, you wrote that in clojure?
13:24	robermann	no, it was in java, it started on 2006
13:24	robermann	but the "sonification" core is now delegated to Max/MSP patches
13:24	robermann	or Pure Data
13:25	robermann	the more interesting java library was jsyn
13:26	zilti	I've seen this piece of code in a presentation (defn describe [[head & tail]] (body here)) and wondered what would happen if it's possible to split the arg in more than two parts. It turned out that [[first & second & tail]] doesn't work. So is the [[x & y]] only syntactic sugar for head and tail?
13:27	zilti	robermann: What did you write? I joined too late but it sounds interesting
13:29	Borkdude	zilti: how about (defn describe [[a b & tail]] [a b tail])
13:30	robermann_	zilti: we were speaking of www.codesounding.org
13:31	zilti	Borkdude: Thanks :)
13:31	robermann_	having some spare time it would be interesting to add a plugin for using overtone
13:32	Borkdude	zilti: & means: all the rest of the args
13:32	zilti	robermann_: That framework sounds like a fun, interesting project. :)
13:32	robermann_	yes, it started as a joke / challenge
13:33	zilti	Borkdude: I'm very new to Clojure. I knew & usually means "varargs" but I didn't know the syntax of [[ ... ]]
13:33	Borkdude	np
13:33	robermann_	zilti: but someone used similar techincs for software metrics: http://sourceforge.net/apps/wordpress/codesounding/2010/08/27/translating-software-metrics-into-music/
13:34	zilti	robermann_: The second example sounds damn futuristic
13:35	zilti	robermann_: Does it only work with Java?
13:36	robermann_	the second example is based on JSyn: http://www.softsynth.com/jsyn/
13:36	robermann_	you can also "pipe" the event to Max/MSP patches
13:36	robermann_	(or pure data)
13:36	robermann_	via UDP packets
13:37	Squeese	why is the quote used here: (require '[clojure.string :as str]) how is the vector list intepreted?
13:37	Borkdude	Squeese: if the quote wasn't there you'd have to quote every single element (except :str) in the vector
13:38	Borkdude	~[a b c]
13:38	Squeese	so its the same as (require ['clojure.string :as 'str]) ?
13:38	clojurebot	bartj: it's not broken. Unless you know the performance hit there is actually a problem, I'd recommend leaving it alone.
13:38	Borkdude	Squeese: yes
13:38	Squeese	Borkdude: hmm, thanks :)
13:38	Borkdude	,(+ 1 2 3)
13:38	clojurebot	6
13:38	Borkdude	,[a b c]
13:38	clojurebot	#<CompilerException java.lang.RuntimeException: Unable to resolve symbol: a in this context, compiling:(NO_SOURCE_PATH:0)>
13:39	Borkdude	,'[a b c]
13:39	clojurebot	[a b c]
13:39	Borkdude	,['a 'b 'c]
13:39	clojurebot	[a b c]
13:39	Borkdude	see? ;-)
13:39	Squeese	yeah :)
13:40	robermann_	zilti: it should be a trivial exerices to use overtone to play the sounds; overtone is written in clojure (http://overtone.github.com/)
13:42	Squeese	ha wow, '[a b '(c d)) gives me: [a b (quote (a b))] did I get a vector with symbos a, b and a list with symbos quote etc?
13:42	Squeese	symbols*
13:42	Borkdude	,(quote ')
13:42	clojurebot	#<ExecutionException java.util.concurrent.ExecutionException: java.lang.RuntimeException: Unmatched delimiter: )>
13:43	Borkdude	eh
13:43	Squeese	, '[a [
13:43	clojurebot	#<ExecutionException java.util.concurrent.ExecutionException: java.lang.RuntimeException: EOF while reading>
13:43	Squeese	ops
13:43	Squeese	, '[a '(b)]
13:43	clojurebot	[a (quote (b))]
13:43	Borkdude	' is a reader-macro for quote
13:43	Borkdude	I think
13:44	Borkdude	(quote [1 2 3]) => [1 2 3]
13:44	Squeese	funny :)
13:44	daniel__	what function do i need here? (map #(???) ("line" "line" "line")) = ("1 line" "2 line" 3 line")
13:44	Borkdude	(quote '[1 2 3]) becomes (quote (quote [1 2 3])) => (quote [1 2 3])
13:44	Borkdude	daniel__ take a look at map-indexed
13:45	daniel__	thanks Borkdude
13:46	Borkdude	,(map-indexed (fn [idx itm] (str idx " " itm)) ("line" "line"))
13:46	clojurebot	#<ClassCastException java.lang.ClassCastException: java.lang.String cannot be cast to clojure.lang.IFn>
13:46	Borkdude	fuck, I should try those out first ;)
13:46	Squeese	Im happy I choose to look into Clojure when deciding between lisp's, not really happening in #scala :P
13:46	alandipert	,(map (partial apply str) (range) (repeat \space) '("list" "list" "list"))
13:46	clojurebot	("0 list" "1 list" "2 list")
13:46	Squeese	+anything
13:47	alandipert	map-indexed would be better if it weren't for the space you need to add
13:48	Borkdude	,(map-indexed (fn [idx itm] (str idx " " itm)) ["line" "line"])
13:48	clojurebot	("0 line" "1 line")
13:48	Borkdude	more readble imho
13:49	daniel__	yep, thanks for the example
13:50	Borkdude	alandipert: I bet you are fond of Haskell? ;)
13:51	alandipert	kinda... i definitely lost the taste for naming intermediate variables somewhere on my quest
13:52	Borkdude	ccorn: what's up, I saw "What action to take on ccorn" in my Aquamacs
13:52	Borkdude	ccorn: didn't know what it was so I ignored it...
13:54	daniel__	,(map-indexed (fn [idx itm] (str idx " " itm)) (repeatedly #(inc %) 1))
13:54	clojurebot	#<ExecutionException java.util.concurrent.ExecutionException: java.lang.ClassCastException: sandbox$eval28$fn__31 cannot be cast to java.lang.Number>
13:55	daniel__	has to be a vector?
13:55	daniel__	,(map-indexed (fn [idx itm] (str idx " " itm)) (vec (repeatedly #(inc %) 1)))
13:55	clojurebot	#<ClassCastException java.lang.ClassCastException: sandbox$eval59$fn__62 cannot be cast to java.lang.Number>
13:55	daniel__	,(map-indexed (fn [idx itm] (str idx " " itm)) (vector (repeatedly #(inc %) 1)))
13:55	clojurebot	#<ExecutionException java.util.concurrent.ExecutionException: java.lang.ClassCastException: sandbox$eval90$fn__93 cannot be cast to java.lang.Number>
13:56	daniel__	,(map-indexed (fn [idx itm] (str idx " " itm)) [1, 2, 3])
13:56	clojurebot	("0 1" "1 2" "2 3")
13:58	Borkdude	daniel__: I think you meant (iterate inc 0)
13:58	dnolen	ibdknox: (- 1), yet another stupid bug in my compiler macro additions. that's fixed now.
13:58	Borkdude	but if you do that here, it will cause map to go over an infinite seq..
13:58	dnolen	if anyone knows how to run the CLJS tests I'm all ears.
13:58	ibdknox	dnolen: :)
13:58	ibdknox	no idea
13:59	Borkdude	daniel__: so you could do (take 10 (iterate inc 0)) or just (range 10)...
13:59	daniel__	Borkdude: yeah...and nvm, i got my code working :)
14:00	ibdknox	dnolen: there used to be a tests script I though
14:00	daniel__	(nth (map-indexed (fn [idx itm] (doto (str idx " " ((fitness-fn target) itm) " " itm) println)) (iterate #(evolve % (fitness-fn target)) source)) generations))
14:00	dnolen	ibdknox: it's there but it doesn't actually run the tests
14:00	dnolen	it just builds the file, and I don't see how to run what it produces.
14:01	ibdknox	hm
14:01	ibdknox	yeah I dunno
14:02	ibdknox	you could compile the tests and run them in the browser?
14:03	ibdknox	dnolen: other option: add the test dir to your classpath for the repl and run the test_runner
14:05	ibdknox	uhoh
14:06	ibdknox	I'm not sure that telling people they shouldn't voice opinions is the way to go :/
14:06	zilti	http://vimeo.com/10896148 (Clojure - Stuart Halloway) seems to be a really awesome presentation for programmers coming from a non-lisp language
14:08	dnolen	ibdknox: I think the point is that some posts are just opinions - not technical discussion. I've done my fair share of opinion mongering :D
14:09	ibdknox	dnolen: Opinions are incredibly important in any community, whether it be technical or not
14:10	dnolen	ibdknox: to a point yes. but don't we have blogs for that?
14:12	ibdknox	dnolen: sure, but the mailing list is also a central meeting place for the community. Some opinions are not valuable, others should be discussed. There's no better place for the latter
14:12	ibdknox	dnolen: The cost of allowing the latter is that you'll get some of the former. That's how communities go.
14:13	dnolen	ibdknox: I don't think the post is necessarily about recent discussions. I think it's about a lot of threads that have astray in the past.
14:13	jli	I'm profiling some clojurescript. it seems like the reader is pretty slow, and 20% of the time is spent in cljs.core.truth. does this make sense?
14:14	ibdknox	dnolen: fair enough. I just know my knee jerk reaction to the email wasn't a good one. I suspect for newish people setting a tone like that will force them away :/
14:14	ibdknox	jli: how old is your clojurescript?
14:14	dnolen	jli: possible, I did some work on inlining truth, but in browsers like Chrome after advanced optimizations it didn't seem to be the bottleneck. Some more scientific benchmarking required tho.
14:15	jli	20% truth_, 9.4% _equiv, 3.2% _count, 3.2% PushbackReader$read_char
14:15	ibdknox	jli: where are you running it?
14:15	jli	ibdknox: master as of last night
14:15	jli	ibdknox: in Firefox 7
14:15	jli	(is that what you mean?)
14:15	ibdknox	yep
14:16	dnolen	jli: can you try that in Chrome as well?
14:16	jli	it seems a lot faster in Chrome
14:16	ibdknox	jli: also, can you put a gist up of what you're running?
14:16	jli	dnolen: what can I use for profiling in Chrome?
14:16	dnolen	jli: the Web Inspector
14:16	ibdknox	jli: it has dev tools in it
14:17	dnolen	jli: the problem w/ inlining truth via the CLJS compiler is that it's not a code size win. You really want something like V8 Crankshaft to do that work for you.
14:23	jli	yeah, chrome is a lot faster. 2.5% _equiv, 2.3% call, 1.3% truth_
14:23	jli	dnolen: you mean Chrome's JS engine is doing the inlining?
14:23	dnolen	jli: yes
14:24	jli	huh, I wonder if that's the main difference?
14:24	ibdknox	probably
14:24	jli	truth_ is all over the place
14:24	jli	327k calls
14:24	dnolen	jli: most likely. The JS engines really should do that work for us.
14:25	dnolen	jli: truth_ is good. It removes all the crazy semantics around JS truthiness / falsiness
14:25	ibdknox	dnolen: I sincerely hope we don't change the property syntax
14:25	jli	yeah
14:25	jli	I'm going to manually inline truth_ in my compiled cljs and see if it's faster in firefox
14:26	dnolen	ibdknox: What's your concern after the discussion?
14:26	ibdknox	dnolen: it's conflating concepts that don't belong together. Interop should be interop. Map-like keyword access should be reserved for maps.
14:29	dnolen	ibdknox: I think rhickey's points about the issue are sound. It's not about interop so much as it's about being able disambiguate property / method calls. We don't have that luxury in JS.
14:29	dnolen	ibdknox: my main concern was only around setting.
14:34	ibdknox	dnolen: his point is that early users were confused by it. Every single one of those early users was a Clojure programmer... They're the only ones that would be confused. A JS person already knows of this distinction
14:35	dnolen	ibdknox: it's also not map-like keyword access really. the dot operator is a special form and not composable.
14:35	dnolen	ibdknox: that's not entirely true, (.foo x 1 2) will be a fn call. (.foo x) won't.
14:36	dnolen	plenty to trip up people who don't know anything about Clojure.
14:36	ibdknox	I think that's an ambiguity that shouldn't exist, but I may be in the minority there
14:38	dnolen	ibdknox: if we don't got there, the above confusion will still exist. the change removes ambiguities around calling conventions.
14:40	dnolen	ibdknox: also some JS apis will do multi-arity stuff via arguments. So in the current system you have to write (. x (foo)) (.foo x 1) (.foo x 1 2)
14:40	ibdknox	that's not trueh
14:40	dnolen	with the proposed change, (.foo x) (.foo x 1) (.foo x 1 2), I think that's a win.
14:40	ibdknox	-h
14:40	ibdknox	(. x (foo)) (. x (foo 1)) (. x (foo 1 2))
14:41	zilti	dnolen what about doto?
14:42	dnolen	ibdknox: the problem here is that . tries to uphold the Lisp convention. fn first. that's abandoning it.
14:43	ibdknox	dnolen: my argument isn't really a technical one, it's about fitting in. Keywords have 0 meaning in the languages that are interop'd with, symbols map logically with the things people are used to.
14:43	ibdknox	dnolen: I've always thought of it as the function being dot
14:43	ibdknox	dnolen: the thing I'm doing it to is x, and what I'm doing is applying some function to it. It's very much like the threading operators which make a lot of sense to me
14:43	srid	can I avoid the `range` in (reduce #(...) val (range (dec (count arg1))))?
14:44	ibdknox	dnolen: it's actually more internally consistent with Clojure I think
14:44	srid	elements of range arrya will be ignored in the reduce fn
14:44	srid	here's the complete function, https://gist.github.com/1289963
14:45	dnolen	ibdknox: (. x (foo)) was always considered a degenerate form as far as Lisp conventions go in Clojure. If . is a function, then it's something like Obj-C msg_send, which just isn't true at all.
14:46	jli	heh: cljs.core.truth_("\ufdd0'else")
14:47	zilti	"(defn index-filter [pred coll] (when pred (for [[idx elt] (indexed coll) :when (pred elt)] idx)))" I don't understand that at all. How does that work?
14:48	dnolen	jli: https://github.com/clojure/clojurescript/tree/80-inline-truth, I have branch w/ truth inlining
14:49	Borkdude	,(doc index-filter)
14:49	clojurebot	Cool story bro.
14:50	Borkdude	zilti, this isn't a std clojure function?
14:51	Borkdude	zilti: (when pred ...) just means: when a predicate is provide
14:51	Borkdude	d
14:51	Borkdude	zilti: thes rest is a standard for with :when guard
14:52	ibdknox	dnolen: like I said, I have no technical ground to stand on and since it's been firmly declared that's what I need, I'll just leave it be.
14:52	zilti	Borkdude: I don't understand that part that's going on in the for part. indexed is supposed to be a function returning pairs
14:53	Borkdude	zilti: I don't think indexed is in clojure.core, keep-indexed is
14:53	zilti	Borkdude: Yes, I know it isn't in the core. I have that code from a presentation slide
14:54	Borkdude	zilti: (keep-indexed pred coll) is what we would write nowadays I think
14:55	zilti	Borkdude: Instead of the whole thing inside the for block?
14:57	dnolen	ibdknox: I agree w/ you as far as aesthetics are concerned. But I just can't see what would be better for JS property access.
14:57	dnolen	we lose a semantic wart and gain an aesthetic one
14:57	ibdknox	dnolen: just leave it be. This is a documentation issue, not something we should special case in the language. This is a result of the host platform
14:58	dnolen	ibdknox: but ClojureScript already removes so many problems that exist in the host.
14:58	Borkdude	zilti: for example (keep-indexed #(if (even? %2) %1) (range 100 110))
14:58	dnolen	ibdknox: proper scoping rules, fixes truthiness/falsiness, etc.
14:58	ibdknox	that's true, but should we really add syntax that only matters for JS?
14:58	ibdknox	dnolen: this is only for interop
14:59	Borkdude	zilti: it means: I'm only interested in the indexes for the numbers in the range that are even
14:59	ibdknox	dnolen: I agree, Clojure abstracts JS away... but you can't abstract the host from features designed to interact with it
14:59	Borkdude	zilti: so it is slightly different than I said at first
15:00	zilti	Borkdude: Apparently a long way to go for me. Where does the second argument in the anonymous function come from?
15:00	Borkdude	zilti: so: (defn index-filter [pred coll] (keep-indexed #(if (pred %2) %1) coll))
15:01	Borkdude	zilti: if you wish: (defn index-filter [pred coll] (keep-indexed (fn [idx elt] (if (pred elt) idx)) coll))
15:01	dnolen	ibdknox: rhickey seemed OK w/ moving forward without addressing it, but fundamental issues like this can end up really creating headaches down the line.
15:01	Borkdude	#(... %1 %2) is an anonymous function, %1 is the first argument, %2 the second, etc
15:01	dnolen	ibdknox: I think by now he has a good idea of what sort of things plague newcomers to a language :)
15:02	ibdknox	dnolen: Ok, so how about a convention that is property accessors are done by (aget x "foo") and make (.foo x) always mean call a method if this is really something that has to be done
15:02	ibdknox	dnolen: I'm not new to languages either :)
15:02	ibdknox	dnolen: and I would argue he generally doesn't care about newcomers, but maybe that's me being cynical based on all of his communications lately
15:03	zilti	Borkdude: I know, but where are the arguments from? Where's the idx arg from and where's the elt argument from?
15:03	dnolen	ibdknox: aget is prevents advanced optimization
15:03	ibdknox	dnolen: I meant less that exact mechanism, and instead something like it. Sorry, that was misleading
15:03	Borkdude	zilti: keep-indexed expects a function of two arguments, the index and the element
15:03	jli	dnolen: if code is testing truth on an expression, do you use a local variable or avoid inlining it?
15:03	Borkdude	zilti: it will index the collection and then apply the function to every index and element of the collection
15:04	dnolen	ibdknox: I don't think that's true at all, but I think he does expect the community to do that work.
15:04	dnolen	jli: if truth test is an expression context, no inlining
15:04	dnolen	ibdknox: ah a new special form
15:04	Borkdude	zilti: so a bit like indexed, only less explicity
15:04	Borkdude	-y
15:05	dnolen	ibdknox: (js-get x foo) ?
15:06	ibdknox	dnolen: given that it's only specific to JS... I guess. Though we could make it something more general as to mean "interop property accessor"
15:06	ibdknox	that way it's at least sensical in other contexts, even if it's unlikely to be used
15:06	ibdknox	hell
15:07	ibdknox	we could extend get to do it
15:07	zilti	Borkdude: Ah it needs a function taking two args. Now I see. Thanks! But, getting back to "(defn index-filter [pred coll] (when pred (for [[idx elt] (indexed coll) :when (pred elt)] idx)))" again, how does that destruction work?
15:07	Borkdude	zilti: keep-indexed is more general than indexed, but you can do the same with it:
15:07	ibdknox	(get x foo)
15:07	Borkdude	,(keep-indexed #(vector %1 %2) ["foo" "bar"])
15:07	clojurebot	([0 "foo"] [1 "bar"])
15:07	ibdknox	I guess it'd be (get x 'foo)
15:08	dnolen	ibdknox: yeah can't overload get like that, 'foo might be a real key in a ObjMap
15:08	ibdknox	dnolen: yeah
15:08	Borkdude	zilti: ah, for has the same destructuring (I think) as let, defn etc
15:09	zilti	Borkdude: It's less about what the code does now, it's more about what is the exact syntax for that destruction thingy - is there an info document somewhere or can you describe that in a few words?
15:09	dnolen	(-get x foo)
15:09	Borkdude	so: (let [[a b] [1 2]] a) => 1
15:10	Borkdude	zilti: just google on clojure destructuring
15:10	ibdknox	dnolen: Maybe we do need to solve this problem, but I don't think the weird syntax proposed is that solution. If we're just doing it for JS, we should do something that makes more sense. Maybe it is (-get ..) or something similar, maybe it's something else entirely.
15:10	ibdknox	dnolen: either way, adding a specific syntax to a space that's already confusing isn't the right thing to do
15:10	dnolen	ibdknox: -get would interesting, - already connotates a low level op. it also mans dot operator is always fn call
15:10	Borkdude	,(for [[a b] [[1 2] [3 4]]] a)
15:10	clojurebot	(1 3)
15:10	jli	Borkdude: zilti: I always look at the docs for let http://clojure.org/special_forms#Special%20Forms--(let%20[bindings%20]%20exprs)
15:11	dnolen	s/man/means
15:11	lazybot	<dnolen> ibdknox: -get would interesting, - already connotates a low level op. it also meanss dot operator is always fn call
15:11	zilti	Borkdude: Oh. indeed. I searched for "clojure destruction" which didn't give me anything useful
15:11	ibdknox	dnolen: that's the kind of consistency we should go for I think
15:12	Borkdude	zilti: the simple case of for is (for [a [some-seq]] ....), in every iteration a becomes the next element from some-seq
15:12	Borkdude	zilti: with destructuring you just destructure on the next element from some-seq
15:13	dnolen	ibdknox: I like the idea of -get, posted on the ML.
15:13	zilti	Borkdude: Thanks a lot. I'll take a look at that. But for today I'm kinda tired and have already learned a lot...
15:14	Raynes	http://stackoverflow.com/questions/3337888/clojure-named-arguments
15:14	jli	blah, so truth inlining reduced the # of calls pretty dramatically, but I couldn't get rid of it everywhere. dnolen: crankshaft is probably able to inline functions even applied to expressions, right?
15:15	dnolen	jli: I would think so.
15:15	Borkdude	zilti: ok, have fun and be careful, because Clojure is addictive
15:15	dnolen	jli: yeah it's impossible to inline truth everywhere because of expression contexts.
15:15	jli	yeah, okay. I guess I'll quit trying to read-string 500 records at a time
15:16	dnolen	if(var x = foo(); ..) { … } sadly not allowed in JS.
15:16	jli	boo
15:17	dnolen	jli: out of curiosity how long is that taking?
15:24	jampart	newbie Q: is there really no way to extend a "class" (datatype) in Clojure?
15:25	dnolen	ibdknox: I'm liking this -get compiler idea macro more and more. We can validation and ensure that x in (-get foo x) must be a symbol.
15:26	dnolen	jampart: there's no subclassing in Clojure if that's what you mean.
15:26	ibdknox	dnolen: yeah, it allows for a much greater degree of flexibility and is internally consistent :)
15:27	dnolen	ibdknox: hopefully people bite, fingers crossed.
15:27	jli	dnolen: to read 490 records (~98k of text) and render relatively straight-forward HTML from it is ~5.5s in Firefox 7 and ~1.8s in Chrome.
15:27	ibdknox	jli: with the inlining?
15:28	ibdknox	jli: you're dealing with seq performance there I bet...
15:28	dnolen	jli: yeah curious about how long that takes w/ inlining, this is a good benchmark.
15:29	ibdknox	dnolen: are you interested in sitting down with folks and talking about the pods stuff at the Conj?
15:29	dnolen	ibdknox: haha, I hardly know anything about Pods, nor how that concept could be leverage efficiently in ClojureScript :)
15:30	jampart	dnolen: so protocols are the only means of subtyping? Can't even subtype records?
15:30	jli	ibdknox: dnolen: that was without. with my manual inlining, it's maybe ~4.7 in firefox and ~1.2 in chrome. dnolen: I'll try your branch later and also try to get more accurate timing
15:30	ibdknox	dnolen: haha I don't either. So I guess maybe the correct thing to say is, would you be interested in working on an efficient seq-like thing
15:30	dnolen	jampart: no subtyping.
15:31	dnolen	jampart: protocols aren't really subtyping.
15:31	jampart	dnolen: so even protocols can't be "derived", as in Haskell's type conditions?
15:32	dnolen	jampart: don't know Haskell that well, but yes from what I understand Haskell support derivation - Clojure does not.
15:33	dnolen	ibdknox: definitely interested in the discussion. we should corner rhickey and get him to give us some pointers.
15:58	btby	I'm new to Clojure. I'm currently going through Peter Norvig's AI book and was wondering if there was an easy way to leverage the Java code for the book (https://code.google.com/p/aima-java/)? I'd like to use Clojure as my exercise language, considering that the original book had Common Lisp as implementation language.
16:02	Borkdude	btby, there is a Peter Norvig AI/Lisp book
16:03	Borkdude	btby: highly recommendable: http://norvig.com/paip.html
16:04	Borkdude	At the time, I found it the best programming book I ever read (halfway through my CS studies)
16:05	btby	Borkdude: Thanks! I've heard about it, but assumed AI: Modern Approach to be a proper superset. Now I'll look closer.
16:05	Borkdude	btby: those are two different books
16:05	Borkdude	btby: the one I mentioned is more about Lisp and shows the power of the language using AI examples
16:06	Borkdude	btby: the other one is more about AI and the code is just there to illustrate how things works in AI
16:06	Borkdude	btby: at least, that is how I understood it while reading both ;)
16:06	btby	Borkdude: I'm using AIMA (the non-Lisp one) for the course I'm taking at the moment.
16:08	Borkdude	btby: I don't really get the question. The lisp code is up here: http://aima.cs.berkeley.edu/lisp/doc/overview.html
16:08	Borkdude	btby: apparently the Java code is also available. Would you like to use it from Clojure?
16:08	Borkdude	btby: or translate it to Clojure
16:09	btby	Borkdude: Yup, using Java from Clojure if it's possible, although if the modification of Common Lisp code is not hard, I'd assume that to be more educational.
16:09	Borkdude	btby: it would definitely a cool project to make a Clojure port ;-)
16:09	Borkdude	br
16:09	Borkdude	be
16:10	btby	Challenge accepted, then. =)
16:11	btby	But in case I need Java to do that last-minute assignment, is it still possible?
16:11	Borkdude	btby: you can do Java interop in Clojure, yes?
16:12	Borkdude	btby: http://clojure.org/java_interop
16:13	gfredericks	so what happens if you try to use clojure 1.3 and one of the deps asks for 1.2?
16:14	btby	Borkdude: Thanks!
16:23	amalloy	gfredericks: in conflicting dependencies, the one specified in the top/main level wins
16:23	gfredericks	huh. I never would have guessed that.
17:15	duck1123	do you need to type hint this when doing gen-class methods, or does it already know the type of that one?
17:34	arohner	duck1123: clojure will infer the types if you're overriding methods. For new methods that don't override anything, you'll need hints
17:35	amalloy	arohner: he was asking about hinting the `this` parameter. i'd be surprised if whether you override a method influences clojure's ability to infer that
17:35	arohner	oh, right. reading comprehension FTW
17:47	droidboi	hi
17:50	droidboi	i am nu 2 this
17:55	droidxmx	what does an N at the end of an int mean?
17:57	gregh	a following M means BigDecimal, but I'm not sure what N means
17:58	gregh	see http://clojure.org/reader for details
17:59	droidxmx	gregh: ok thx
17:59	ibdknox	,(type 1N)
17:59	clojurebot	clojure.lang.BigInt
18:00	ibdknox	droidxmx: ^
18:00	droidxmx	cool
18:02	droidxmx	'nox: nice one
18:02	gregh	,(type 1M)
18:02	clojurebot	java.math.BigDecimal
18:03	gregh	so does /reader need to be updated to add N?
18:08	droidxmx	,1
18:08	clojurebot	1
18:08	todun	I was using emacs to work and the swank server connection closed. This is confusing me because I thought it is a server running on my local machine. Is this normal?
18:09	droidxmx	nice
18:09	Apage43	todun: if the jvm it was running in died or crashed for some reason
18:10	todun	Apage43: I see. what if there is no warning?
18:10	todun	Apage43: the jvm doesn't give any warning. can it still just randomly crash?
18:10	ivan`	is there an Anki or Mnemosyne deck with Clojure flashcards anywhere?
18:14	Apage43	todun: shrug depends what caused it to blow up
18:14	todun	so I shouldn't worry about it I guess..
18:14	todun	thanks.
18:15	Apage43	probably not. If it keeps happening you might want to care more.
18:17	todun	Apage43: ok.
18:25	kanja	I'm having a ton of trouble getting slime installed with clj - I keep getting errors like: "Symbol's function definition is void:
18:25	kanja	define-slime-contrib" when trying to enter slime mode. I found the offending line in swank-clj's definition, but I don't know where slime-contrib should be. Any ideas?
18:26	amalloy	don't use swank-clj. it's like a hundred years old
18:26	amalloy	er
18:26	amalloy	no, that's ritz's new name, isn't it? i'm not sure now
18:27	kanja	it's in the package.el repository, and most of the install walkthroughs I see use it...
18:29	amalloy	kanja: from https://github.com/pallet/ritz it looks like swank-clj was renamed to ritz, not the other way round. but anyway, i was thinking of slime-clj, which definitely is old :P
18:30	kanja	amalloy: ah - yeah I'm tyring to get slime-clj installed. If that's old, what should I use instead?
18:31	amalloy	kanja: have you looked at that github link? he seems to bundle slime-ritz with the swank package
18:33	amalloy	i never got ritz working, myself; i still use the older swank-clojure with one of technomancy's snapshots of slime
18:33	kanja	I'm kind of a newb with slime/swank actually - I'm not really sure how to use it
18:37	todun	I am writing the following routine to remove duplicates. I think the problem is with the second condition to cond, but whenever I try to give it an independent expression, the emacs indentation complains that it's wrong: http://pastebin.com/kWDvPDQ8
18:37	todun	any help is appreciated. thanks.
18:40	amalloy	todun: you seem to have included (rest lst) inside of the (and) test instead of after it
18:40	todun	amalloy: yes. I realize that. but emacs complained about my indentation when I did otherwise. and I get an exception when I run it.
18:41	todun	run it with both the (rest lst) in and out of the and block(is that what it's called?).
18:41	amalloy	emacs is not complaining about your intentation; cond just doesn't indent in a very readable manner
18:41	amalloy	your exception is due to there being other issues
18:41	todun	amalloy: that figures :P
18:42	amalloy	for example, (rd (lst)) should probably be (rd lst)
18:43	todun	amalloy: oh. I can leave the list out of parens?
18:43	todun	I see. ok.
18:43	amalloy	it's nothing to do with "can you leave it out". parens always (except when they don't, as discussed yesterday) mean "call the stuff inside as a function"
18:44	todun	amalloy: ok. sorry. I keep thinking of lists like an exception. thanks.
18:48	todun	amalloy: thanks. it compiles now. testing it...
18:52	todun	amalloy: now I get a stackoverflow. I know if you do recursion in clojure for large values without using compiler optimizations you get SO. But for small values what could be causing my SO? http://pastebin.com/ynVTZiwt
18:52	amalloy	:else (rd lst) - your else clause just starts the same job over again without simplifying it
18:54	todun	amalloy: I thought doing that in cond's and clause took care of it in the call back to the function, or no?
18:54	Apage43	also you can recur there, no?
18:54	todun	Apage43: ok I will try that.
18:54	Apage43	todun: you haven't modified lst..
18:55	todun	Apage43: I'm wary of that because I try it for another function I write and I get my REPL hanging...
18:55	todun	Apage43: modified lst?
18:55	Apage43	(rd lst)
18:55	Apage43	will call rd with exactly what it was originally called with
18:56	Apage43	so naturally if you hit that branch it'll be an infinite loop
18:56	todun	Apage43: will call recur in place of else solve that problem, no?
18:56	Apage43	.. no.
18:56	todun	uhm ok.
18:57	Apage43	What are you intending to pass to the function when you call it again?
18:58	todun	a list
18:58	Apage43	containing...
18:59	todun	for example
18:59	todun	given (1 2 3 1 4 1 2), returns a sequence containing the elements (1 2 3 4),
18:59	todun	in some order.
19:00	Apage43	well yes that's what you want rd to do
19:00	Apage43	but specifically i'm talking about the part where you're recurring
19:00	Apage43	what do you want to pass to rd in the next step
19:01	todun	Apage43: oh ok.
19:02	todun	Apage43: I want to give it the list
19:02	todun	that is reduced
19:02	todun	from the previous steps.
19:05	archaic	is there a way to directly destructure a map in the binding: into ks and vals? ie (defn [m] (let [ks (keys m) v (vals m)] ...)
19:05	Apage43	sorry, can't wrap my head around what you're trying to do =/
19:05	gfredericks	archaic: well what you have there would certainly work if that's what you want. But there's a whole syntax for destructuring maps too
19:05	gfredericks	e.g., assigning specific keys to specific names
19:06	archaic	yea thats what i mean
19:06	gfredericks	and a few other features
19:06	gfredericks	but what you did there is not translatable into map destructuring
19:06	gfredericks	so I'm not sure what specifically you want
19:06	todun	Apage43: was that directed at me?
19:06	Apage43	,(let [map {:a 1 :b 2}] (let [{a :a b :b} map] [a b]))
19:06	clojurebot	[1 2]
19:07	gfredericks	archaic: that ^ there is certainly an example
19:07	gfredericks	archaic: and this here I just googled seems to go over it in detail: http://blog.jayfields.com/2010/07/clojure-destructuring.html
19:08	archaic	I wanted something like (defn [[ks val] m]) where ks and vals are the keys and vals in m, rather than what I first wrote, since I seem to be using that alot
19:09	gfredericks	,(let [m {:a 1 :b 2 :c 44}, [ks vs] ((juxt keys vals) m)] [vs ks])
19:09	clojurebot	[(1 44 2) (:a :c :b)]
19:09	archaic	yah that works, would that be reasonable macro?
19:09	gfredericks	archaic: aside from that kind of ugly mess, there's not direct support. I'm curious why you end up doing it a lot though.
19:11	gfredericks	also I don't know what you meant by "would that be a reasonable macro?"
19:11	gfredericks	since what I did was not a macro
19:12	archaic	I know, I meant wrapping what you did to get rid of the 'uglyness
19:13	gfredericks	rather than a macro I would just def (juxt keys vals) somewhere and use that
19:13	gfredericks	(def kvs (juxt keys vals)) and then (let [[ks vs] (kvs m)] ...)
19:13	archaic	yeah that works, thanks
19:14	gfredericks	sure
19:16	archaic	i still haven't found need to write a macro ever yet though :\ in about 3 months of clojure
19:16	gfredericks	that's a good sign.
19:18	archaic	except if your trying to learn them
19:19	gfredericks	why would you be trying to learn them if you don't need them? :)
19:23	todun	is it possible to pass the name given to a function in a let binding to the argument of a recursion?
19:23	gfredericks	o_o
19:23	amalloy	todun: first of all, you know distinct already exists, right? you're implementing remove-duplicates for practice?
19:24	todun	amalloy: yes.
19:24	todun	to practice my recursion
19:24	amalloy	okay. well i think your algorithm is impossible, so working on your syntax is not going to help
19:24	todun	amalloy: oh. sigh.
19:25	todun	I'll appreciate any suggestions. thanks.
19:25	amalloy	in order to remove duplicates of some sub-list x, you need to know what elements have already been "selected" to return in the previous iterations
19:25	todun	amalloy: so. using let can help, no?
19:25	todun	as in binding that output to the next call.
19:26	todun	*recursive.
19:28	gfredericks	todun: is your code posted somewhere?
19:28	todun	gfredericks: yes. let me repost it...
19:28	amalloy	todun: here's a quick sketch i put together trying to stick to simple language features: https://gist.github.com/1290310
19:29	archaic	todun, I would do something like (reduce some-fn #{} coll) where some-fn uses contains? to check for duplicate
19:29	todun	gfredericks: http://pastebin.com/ynVTZiwt
19:30	amalloy	the key point is that you have to manually track what elements have already been returned - given just the "current" sub-list you can't tell which elements of it to return
19:30	todun	amalloy: archaic seeing allot of new notation here. will take me a second to comprehend it all.
19:31	todun	amalloy: ok. so using a compare between adjacent elements is not a good idea?
19:31	amalloy	todun: then how would you fix '(1 2 1) into just '(1 2)?
19:32	todun	that's why I was simultaneously checking if the list was distinct.
19:34	Apage43	todun: checking if distinct is distinct?, btw. distinct removes duplicates.
19:34	todun	Apage43: yes. it is sort of backwards. I was hoping to learn the different forms of recursion in clojure.
19:35	amalloy	todun: you're implementing distinct yourself. if you use it as part of your solution, you might as well just make it your whole solution
19:35	amalloy	(def rd distinct)
19:36	gfredericks	brilliant!
19:36	todun	amalloy: true :)
19:36	Apage43	you can always look at how distinct is implemented. Mind it is lazy: https://github.com/clojure/clojure/blob/f5f827ac9fbb87e770d25007472504403ed3d7a6/src/clj/clojure/core.clj#L4413
19:37	gfredericks	huh. I didn't know it was lazy. ##(take 5 (distinct (range)))
19:37	lazybot	⇒ (0 1 2 3 4)
19:37	gfredericks	well I'll be.
19:37	todun	Apage43: thanks.
19:38	todun	amalloy: I'm still looking at your code and you use recur. I have code I wrote that uses recur. It compiles fine but it runs like for ever on small input. I think I'm missing the point of all these recursion optimizations. Can I post it?
19:39	amalloy	you can post anything you want :P. in this case i was using recur mostly because i wanted a loop, not because i wanted to "optimize" it
19:39	todun	amalloy: ok. thanks. http://pastebin.com/5txqZnU8
19:40	todun	amalloy: that is so counter-intuitive that I'm not sure I understand. how can you use(surely you did and it works) recur to make a loop?
19:40	todun	amalloy: or is this idiomatic clojure?
19:40	gfredericks	ironically, this recursive reversal seems like a great non-use-case for loop/recur
19:41	gfredericks	i.e., the simplest way is to use traditional recursion
19:41	gfredericks	(defn rreverse [coll] (reverse (map rreverse coll)))
19:42	gfredericks	except I forgot the base case
19:42	gfredericks	well it works for infinitely nested lists anyways :)
19:43	gfredericks	todun: the problem with using recur for rreverse is that recur only lets you make one recursive call. If you want to rreverse every element in the input list, you'd want to recurse for each element.
19:44	gfredericks	which you can't do with recur
19:44	todun	gfredericks: I see.
19:44	todun	gfredericks: will a lazy seq do something similar?
19:45	gfredericks	recur has a lot more in common with imperative languages' loops than with the things that you would normally do recursively in an imperative language
19:45	Apage43	recur is not a function call. it means "rebind these vars and jump to the recursion point (beginning of the fn, or loop, usually)"
19:45	todun	gfredericks: since lazy seqs should only do work when they have.
19:45	gfredericks	todun: I think that's kind of a separate issue.
19:45	todun	Apage43: ok.
19:45	todun	gfredericks: oh?
19:46	gfredericks	todun: mostly because I don't see how it relates :)
19:46	gfredericks	todun: your whole goal at the moment is to learn recur, is that correct?
19:46	todun	gfredericks: yes. or recursion in general.
19:47	gfredericks	what other languages are you familiar with?
19:47	archaic	ohhh I didn't know you could do nested destructuring nice.. refactor time (defn binding-test [{[x & xs] :content}] [x xs]
19:47	todun	gfredericks: though I'm brand new to programming, I've dabbled in quite a few.
19:47	todun	java, scala, python.
19:48	todun	I'm not particularly good in any of them. but I'm still learning. so if I say something that doesn't make sense..well, you know why.
19:48	gfredericks	huh. I hadn't prepared a general recursion lecture.
19:49	gfredericks	I assume you came across the term "tail call" recently?
19:50	todun	yes. sort of.
19:50	todun	gfredericks: especially in my clojure readings.
19:50	todun	TCO.
19:51	gfredericks	yeah
19:51	amalloy	when i was learning lisp, i had this idea that it was all about writing recursive functions, especially tail-recursive
19:51	todun	amalloy: oh.
19:51	amalloy	and in some ways, it is, but mostly you can let the standard-library functions do all the recursion for you, and write your code in terms of map, reduce, and so forth
19:52	todun	amalloy: ok. relying on higher-order functions to do the work.
19:52	amalloy	right. like gfredericks's definition of deep-reverse in terms of map instead of manual recursion
19:52	todun	amalloy: sadly, that doesn't help my agenda of learning recursion.
19:53	gfredericks	todun: do you have any actual problems/projects you're working on, or are you simply trying to learn clojure?
19:54	amalloy	&(letfn [(rreverse [coll] (if (sequential? coll) (reverse (map rreverse coll)) coll))] (rreverse [1 2 [3 4 5 {6 7} [8 9]]]))
19:54	lazybot	⇒ (((9 8) {6 7} 5 4 3) 2 1)
19:54	todun	amalloy: I think clojure can be instructive in this way, because it has so many idiomatic ways of doing recursion. I just have to
19:54	todun	amalloy: both actually.
19:55	gfredericks	todun: I think the "so many ways" that you're thinking of is really just an unfortunate side-effect of the JVM rather than an intentional language feature
19:55	todun	amalloy: one is one for school hw. another is for learning programming.
19:56	todun	gfredericks: ok.
19:56	gfredericks	ideally there's just one way to do recursion, and TCO happens whenever possible
19:57	todun	gfredericks: ok. how so?
19:57	gfredericks	a function calls itself
19:57	gfredericks	that's how it works in haskell and erlang.
19:57	todun	gfredericks: uhm. ok. that makes sense.
19:57	gfredericks	I think (loop) is just syntactic sugar, as you could do the same thing with (fn ...)
19:58	amalloy	yes
19:58	todun	gfredericks: not too familiar with the mechanics in those languages but I've seen they do allow TCO(at least erlang)
19:58	gfredericks	amalloy: do you know why loop is listed as a special form?
19:58	todun	gfredericks: actually I was just reading up on loop now.
19:59	amalloy	gfredericks: technically only loop* is a special form
19:59	Apage43	todun: exactly. because they have TCO, the optimization happens automatically
19:59	todun	gfredericks: it seems like a way to do any kind of recursion you want.
19:59	amalloy	but the docs are pretty vague about it
19:59	ibdknox	I think I'm missing the point of Clojure-Dev list :/
19:59	Apage43	todun: clojure does not have TCO, which is why it has recur
19:59	gfredericks	amalloy: I just read today that "several special forms are actually implemented as macros" and it was weird. Made me think I don't know what "special form" means, because I thought it was mutually exclusive with macros.
19:59	amalloy	gfredericks: loop could be implemented as a macro on top of fn, but for performance reasons it is not
20:00	todun	Apage43: ok. I know scala has TCO and it relies on the JVM too.
20:00	todun	Apage43: why is clojure different?
20:00	gfredericks	amalloy: okay, that makes sense of it
20:00	gfredericks	amalloy: assuming that the quote I just mentioned was mildly incorrect and the starred versions are the actual special forms
20:00	amalloy	gfredericks: you're right, special forms and macros are distinct and non-overlapping. but if you pretend that loop* doesn't exist, then loop is kinda like a special form
20:01	gfredericks	amalloy: so you think the docs page claims that let/fn/loop are special forms just for simplicity?
20:01	amalloy	yes
20:01	Apage43	todun: Scala can do what clojure's recur does, but it can't do TCO when the tail-call is not to the same function
20:01	gfredericks	kay. my world is right again.
20:02	gfredericks	Apage43: but clojure can't do it even when it is to the same function. I assume that's because it's dynamic.
20:03	Apage43	right
20:03	amalloy	gfredericks: clojure could do that but chooses not to. dynamism doesn't enter the picture
20:03	Apage43	clojure could just detect where you could use recur and replace it with recur
20:03	todun	Apage43: I thought scala couldn't do mutual recursion but could tco?
20:03	Apage43	but if we force you to use recur you can more easily understand when you are and aren't going to be consuming stack
20:04	gfredericks	amalloy: what's the rationale then?
20:04	amalloy	gfredericks: <Apage43> but if we force you to use recur you can more easily understand when you are and aren't going to be consuming stack
20:05	Apage43	you absolutely -know-, in clojure, that if you aren't using recur you are adding a stack frame
20:05	gfredericks	amalloy: so clojure just hates implicit TCO regardless of the jvm?
20:05	ibdknox	eh
20:05	todun	Apage43: so recur is like tco then, like the book says, no?
20:06	ibdknox	as hiredman said it the other day, if the JVM had TCO, Clojure would have TCO too
20:06	amalloy	i don't think so. if tco to other functions were possible, clojure probably wouldn't demand a special annotation saying "please do it"
20:07	gfredericks	okay, so it prefers all or nothing
20:07	gfredericks	rather than "just to self"
20:07	ibdknox	gfredericks: consistency is king
20:07	ibdknox	without consistency, it's impossible to be "simple"
20:08	gfredericks	I'm still confused about why dynamism has nothing to do with it.
20:08	gfredericks	would it not be a problem if a function altered the var it pointed to and then invoked that var "recursively"?
20:09	Apage43	recur is nice compared to automatic self-call optimization because you can't THINK it's going to work, have it compile and run, and then perform really badly because it couldn't do the optimization
20:09	Apage43	if recur won't work, it won't compile
20:09	ibdknox	Apage43: I'm with you, I think being explicit in this case is valuable
20:10	gfredericks	s/it pointed to/that pointed to it/
20:10	lazybot	<gfredericks> would it not be a problem if a function altered the var that pointed to it and then invoked that var "recursively"?
20:10	Apage43	gfredericks: that's not self-recursion anymore, and not even scala can do that
20:11	gfredericks	Apage43: I'm not arguing it is I'm arguing the compiler couldn't tell that's not happening
20:11	gfredericks	so how is it possible to implement self-recursion in clojure?
20:12	gfredericks	I'm specifically responding to amalloy's "clojure could do that but chooses not to. dynamism doesn't enter the picture
20:12	gfredericks	"
20:15	amalloy	gfredericks: i think it's pretty hard to write code that does that even without implicit tco
20:15	gfredericks	you mean unintentionally?
20:15	amalloy	even on purpose you have to try pretty hard
20:16	gfredericks	(defn foo [& args] (foo (alter-var-root! foo ...)))?
20:16	amalloy	no good
20:16	gfredericks	how come?
20:16	amalloy	&(macroexpand '(defn foo [& args] (foo (alter-var-root! foo inc))))
20:16	lazybot	⇒ (def foo (.withMeta (clojure.core/fn foo ([& args] (foo (alter-var-root! foo inc)))) (.meta (var foo))))
20:16	amalloy	the internal foo is not referring to the var at all,but to the local function name
20:17	gfredericks	okay, so then write it like the expanded version but without the function name
20:17	gfredericks	(def foo (fn [& args] (foo (alter-var-root! foo ...))))
20:18	amalloy	gfredericks: and now foo gets evaluated for the function call before the alter-var-root happens
20:18	Apage43	it could just choose not to do the optimization for unnamed functions
20:18	amalloy	i'm just saying, it might be possible to trick the compiler, but it's very hard to write code that does that and is otherwise correct
20:19	gfredericks	okay
20:19	amalloy	but anyway that's not a self-call anymore - it's a function calling to a named var
20:20	amalloy	which happens to, for the moment, contain the same functino
20:21	gfredericks	I guess I didn't imagine an implicit-self-call-TCO implementation that distinguished, but I guess that'd be the way it would have to go, and it would still be useful based on what you just lernt me about the defn macro
20:22	Apage43	very good reason to leave them alone once you set them =P
20:23	amalloy	(binding [binding let] (...profit???))
20:23	gfredericks	lol
20:24	gfredericks	I figured out just in my own head that that wouldn't compile
20:26	amalloy	&(with-bindings {#'binding #'let} (binding [inc dec] (inc 1)))
20:26	lazybot	⇒ 2
20:27	amalloy	that one compiles but doesn't actually do anything, which makes it more fun
20:31	droidxmx	hi
20:32	gfredericks	droidxmx: hi
20:32	droidxmx	hi gf
20:32	droidxmx	sup
20:33	gfredericks	vars
20:34	droidxmx	?
20:34	droidxmx	vars?
20:34	clojurebot	http://www.slideshare.net/mudphone/fun-with-vars
20:34	gfredericks	(inc clojurebot)
20:34	lazybot	⟹ 6
20:35	droidxmx	what is that?
20:37	gfredericks	what is what? vars?
20:38	droidxmx	yes
20:38	gfredericks	holy crap how did I go this long without knowing about with-out-str?
20:39	gfredericks	droidxmx: clojure.org/vars
20:40	gfredericks	droidxmx: I only mentioned it because it was the last thing that was talked about before you showed up
20:43	amalloy	hah, another excellent reason not to waste space by saying hi to everyone when you arrive. if you do, gfredericks will start talking nonsense at you
20:44	duck1123	So in 1.3, unchecked-divide is just / right?
20:49	amalloy	duck1123: that would surprise me. 1.3 doesn't default to ratios anymore?
20:50	duck1123	right... so where did unchecked divide go?
20:50	dnolen	,clojure-version
20:50	clojurebot	{:interim true, :major 1, :minor 3, :incremental 0, :qualifier "master"}
20:50	dnolen	,(/ 1 2)
20:50	clojurebot	1/2
20:51	dnolen	,unchecked-divide
20:51	clojurebot	#<CompilerException java.lang.RuntimeException: Unable to resolve symbol: unchecked-divide in this context, compiling:(NO_SOURCE_PATH:0)>
20:51	duck1123	I'm trying to compile aleph with 1.3 (ie. check all the things)
20:52	gfredericks	maybe it's what you get when you pass floats to /?
20:54	amalloy	,(find-doc "unchecked")
20:54	clojurebot	-------------------------
20:54	clojurebot	clojure.core/unchecked-math
20:54	clojurebot	While bound to true, compilations of +, -, *, inc, dec and the
20:54	clojurebot	coercions will be done without overflow checks. Default: false.
20:54	clojurebot	-------------------------
20:54	clojurebot	clojure.core/unchecked-add
20:54	clojurebot	([x y])
20:54	clojurebot	Returns the sum of x and y, both long.
20:54	clojurebot	Note - uses a primitive operator subject to overflow.
20:54	clojurebot	-------------------------
20:54	amalloy	uhoh
20:54	clojurebot	clojure.core/unchecked-add-in...
20:54	gfredericks	I guess that would imply it doesn't exist in the same sense though
20:54	dnolen	duck1123: unchecked-divide probably doesn't make much sense - long / integer will get you a ratio.
20:55	dnolen	duck1123: if you coerce to double / float, you don't need unchecked.
20:55	amalloy	dnolen: perhaps just use quot?
20:55	duck1123	in the place I found it, it was dividing 2 longs. I presume the unchecked- was for speed
20:58	dnolen	duck1123: fwiw I had a similar problem in core.logic, you can abstract away the difference between 1.2.0 / 1.3.0 with a macro over the specific operation.
21:24	gfredericks	huh...the special forms page suggests that docstrings should be short: 1-3 lines
21:28	duck1123	gfredericks: that was before marginalia
21:29	gfredericks	wait is this awesome?
21:30	duck1123	marginalia would be more awesome if it extracted my doc strings correctly
21:30	gfredericks	why doesn't it?
21:30	duck1123	for the projects it works for, it looks awesome
21:31	duck1123	there's some odd bug, there's a ticket in for it, but I haven't looked too deeply
21:31	duck1123	it pulls out all my ;; comments, but none of my docstrings
21:32	gfredericks	huh.
22:54	kanja	I'm trying to get ritz swank working, and I'm getting "FileNotFoundException Could not locate swank/swank__init.class or swank/swank.clj on classpath" when I'm attempting to load slime - I'm assuming that I need to alter my classpath, but I don't know how - can someone point me to a resource on setting my classpath?
23:34	duck1123	kanja: do you have swank-clojure declared as a dependency?
23:36	amalloy	duck1123: that's frowned on these days anyway, right? supposed to install it as a plugin instead
23:37	duck1123	right, but he's using ritz, and if it's anything like the maven plugin, you need to declare it
23:37	duck1123	using lein, sure, you should just install it as a plugin
23:38	kanja	duck1123: I think I don't? I attempted to install it via `lein plugin install ritz 0.1.7`
23:38	kanja	but that doesn't do anything with emacs, does it?
23:38	kanja	er nm, stupid quesiton
23:38	duck1123	using ritz, you still call mvn to do stuff, right?
23:39	kanja	I have no idea :(
23:39	duck1123	I would try declaring swank as a dependency
23:39	amalloy	i thought there was a lein-ritz
23:39	duck1123	is there? I thought it was just for maven
23:40	duck1123	I'm thinking of Zi
23:40	amalloy	if anyone out there is developing stuff for clojure users that only works for maven, we should probably find out where they live and kill them
23:40	duck1123	well then, try installing the swank plugin as well
23:40	kanja	arg, why is getting slime setup so hard :(
23:41	kanja	try installing the swank plugin?
23:41	duck1123	lein install plugin swank-clojure 1.4.0-SNAPSHOT
23:41	kanja	thanks
23:42	kanja	that seemed to do something
23:42	duck1123	I think there's a more stable version, but that works well for me with 1.3
23:44	duck1123	amalloy: I think a maven plugin is an acceptable exception for maven only
23:45	kanja	still not swank on my classpath...
23:46	amalloy	i don't even really know what a maven plugin is, so i can't argue this point
23:46	kanja	Why were people saying not to use swank-clojure? That was updated two days ago
23:47	duck1123	You're not supposed to declare swank as a dependency of your project
23:47	ibdknox	yeah, no more swank deps :p
23:47	duck1123	there have been a lot of changes to swank, and people were linking to old versions and it was causing problems
23:48	duck1123	with lein's plugin system, there's no need
23:48	duck1123	Of course, I say this knowing that I declare swank as a runtime dependency
23:48	duck1123	But that's only because I launch a swank server as a side effect of starting my server
23:49	kanja	so m-x slime breaks, but closjure-jack-in works? Why the extra command?
23:49	duck1123	kanja: try lein-swank then M-x slime-connect
23:50	duck1123	it's really pretty easy
23:50	duck1123	I have a fn called slime-connect-to-server that connects to the default host port that I have bound to a key combo, it's effortless to connect
23:51	duck1123	er: lein swank
23:53	kanja	Yeah, that works. Thanks!
23:53	kanja	Why does just m-x slime blow up then?
23:54	duck1123	M-x slime tries to start the server. Since it's designed for common lisp, it's a PITA
23:54	amalloy	kanja: that's trying to use CL slime
23:54	kanja	ahhhh
23:54	kanja	I see
23:54	kanja	makes sense
23:55	kanja	no wonder it's blowing up on the swank dependency then
23:55	duck1123	clojure-jack-in tries to eliminate the need to run lein swank
23:56	kanja	very cool
23:56	kanja	sorry I'm such a newb at this, I'm just starting to get setup with the clj ecosystem
23:57	duck1123	just to check, are you using an up to date emacs, using the starter kit? getting everything from elpa?
23:58	kanja	Yeah I'm using elpa, although that's pretty new to me. I've been stuck in a rut with my emacs conf for a long time
23:58	kanja	running emacs 23.3.1