#clojure – 2011-04-04

2011-04-04

00:00	amalloy	MiggyX: raek has a blog post somewhere that does this
00:00	amalloy	$google executors in clojure raek
00:00	sexpbot	First out of 33 results is: Executors in Clojure - raek's blog
00:00	sexpbot	http://blog.raek.se/2011/01/24/executors-in-clojure/
00:42	bettsp	Hi guys, I'm working my way through The Joy of Clojure and I'm having trouble with an example
00:43	bettsp	http://pastie.org/1753072
00:43	bettsp	This reports "No implementation of method: :cat of protocol: #'user/Concatenatable found for class: java.lang.String"
00:47	amalloy	bettsp: works for me. maybe you're on the wrong clojure version
00:47	brehaut	bettsp: can you run clojure-version
00:48	brehaut	(in your repl)
00:48	bettsp	brehaut: Well I'm going through vimclojure (nailgun), my lein file depends on 1.2.0
00:49	amalloy	brehaut: this should work on 1.2.0 - try doing what brehaut asked to see if you're actually on 1.2.0
00:49	bettsp	amalloy: Yep, 1.2.0
00:49	amalloy	hm
00:50	bettsp	Maybe it's a weird Nailgun / vimclojure quirk
00:50	bettsp	Let me try using clj directly
00:50	amalloy	you may need to restart your repl
00:50	amalloy	some things have a sort of "once-only" semantics
00:51	bettsp	amalloy: Yeah, I think that was it. Thanks
00:53	amalloy	when all else fails, try rebooting
00:57	ataggart	amalloy: do you have permissions on jira?
00:57	amalloy	no
00:57	ataggart	k
00:57	amalloy	what for, ooc?
00:58	ataggart	I can submit tickets, add/delete attachments, etc., but I can't change any of the field values, e.g., "waiting on". I was just wondering if that was expected, or I'm missing some obvious button somewhere.
00:59	ataggart	I'd rather not pester Stu every time I update something.
01:27	ataggart	&(Integer/toBinaryString -2)
01:27	sexpbot	⟹ "11111111111111111111111111111110"
01:27	ataggart	&2r11110
01:27	sexpbot	⟹ 30
01:42	marko_	can I create this task in leiningen on intelliJ: clean, deps, jar and move .jar to other destination folder with one combined command?
03:54	marko_	is it possible to get current file path with File. on clojure? say im on ns projects.core and want to get whole system path to the same file?
03:57	marko_	im trying (.getPath (File. ""))
04:19	TobiasRaeder	Morning
06:42	markskilbeck	Hi, all.
06:42	markskilbeck	Is it possible to open a jar from the repl?
06:51	zmyrgel	I have a list of vectors like ([1 a] [2 b] [3 c] ...). What would be a idiomatic way to return the vector with highest number from it?
06:52	alfborge	Is it sorted?
06:52	zmyrgel	no
06:52	zmyrgel	making changes to my code and previous version had just a list of numbers so I had (apply max my-list)
06:53	alfborge	Will you use the list to retrieve other vectors later?
06:53	opqdonut_	zmyrgel: reduce with a (fn [x y] (if (<= (first x) (first y)) y x))
06:53	zmyrgel	no, I just need the highest vector from it
06:56	zmyrgel	opqdonut_: seems to work just fine
07:01	yason	zmyrgel: (last (sort yourlist)) but efficiency-wise the right solution really depends on how you use the list of vectors
07:02	raek_	,(apply max-key first '([1 a] [2 b] [3 c]))
07:02	clojurebot	[3 c]
07:02	zmyrgel	raek_: seems nice solution, no need for extra code
07:03	raek_	markskilbeck: what do you mean by "open a jar"? use libraries from it?
07:03	zmyrgel	yason: It's part of my chess game tree evaluation
07:03	markskilbeck	I apologise for my poor terminology. I just want to use the gtk.jar, without having to quit and restart the repl.
07:03	markskilbeck	Is that possible?
07:03	zmyrgel	The max value goes to new list where I choose the minimum value and that again to new list
07:04	raek_	markskilbeck: you can use (add-classpath "file:///absolute/path/to/file.jar"), but add-classpath has been deprecated
07:04	zmyrgel	though my minimax seems to have slight error in it :)
07:05	zmyrgel	seems to return the game state of the cutoff point and not the next state
07:05	markskilbeck	raek_: I noticed that. Still, I get an error when doing (import 'org.gnome.gdk Event)
07:05	markskilbeck	Class doesn't exist.
07:06	raek_	markskilbeck: there's an error in you syntax: (import '(org.gnome.gdk Event))
07:07	raek_	either that or simply (import 'org.gnome.gdk.Event)
07:07	markskilbeck	Oh I see.
07:08	markskilbeck	Thanks raek_
07:14	raek_	anyone know where I can read about the details why add-classpath was deprecated?
07:14	yason	zmyrgel: if you do this operation constantly, then you could either keep the list sorted, keep track of the biggest item before hand, or use a reduction as described above to run through the list quickly. But if this isn't in the inner loop and especially if the list is quite short, it's probably cleanest to just sort+pick last
07:14	raek_	all I know is that it turned out to not work consistently
07:33	marko	im running clojure.contrib.shell-out to execute a shell script, but the problem is, that output of shell script is printed after execution, not realtime, can this be solved somehow?
07:53	waxrose	,(instance? Integer 10)
07:53	clojurebot	true
07:53	waxrose	weird
07:56	markskilbeck	waxrose: why is that weird?
07:56	waxrose	markskilbeck, My REPL is outputting that as false.
07:56	waxrose	Which I know it shouldn't.
07:56	markskilbeck	I get true.
07:57	waxrose	hmm, maybe my repl is out of wack
07:57	clojurebot	c'est bon!
08:00	raek	in 1.3, boxed integer numbers are always of type Long
08:01	waxrose	oh, thanks
08:02	waxrose	I thought I was going crazy. :3
09:17	TimMc	hey wax
09:57	fliebel	&(let [kv (clojure.lang.MapEntry. :a 1)] (identical? kv (first (into {} [kv]))))
09:57	sexpbot	⟹ false
09:57	TimMc	Not terribly surprising.
09:58	fliebel	TimMc: I guess, not, but why does it tear apart these entries?
09:58	TimMc	Maps can be implemented as trees, hash tables, etc.
09:59	TimMc	I suspect the entries have to be torn apart for those.
10:00	fliebel	TimMc: And then? In the end you need to get the key and the value back together, right?
10:00	TimMc	For iteration, sure.
10:02	fliebel	I guess I don't understand enough of maps then…
10:04	fliebel	Okay, say you have a binary tree, which you go down in left or right with hash < node or whatever. Now, dos it really matter if you store the value down there or the MapEntry? Hm, I guess it's just efficiency then?
10:05	fliebel	Anyway, I made a type that implements IMapEntry, and when iterating over it, I naively expected to get back my objects, rather than vanilla objects.
10:09	kumarshantanu	hi, anybody deeply familiar with Leiningen plugins here? (eval-in-leiningen and eval-in-project)
10:10	TimMc	Not I, but ask your question anyway.
10:11	alfborge`	This is probably a stupid question, but are the people behind leiningen and cake enemies?
10:11	alfborge`	Or friends?
10:13	TimMc	Friendly competitors, I think.
10:13	TimMc	I don't actually know who the maintainer of cake is.
10:13	alfborge`	I suspect he's from ruby... cake => rake ... hmmm...
10:14	TimMc	Ah, yeah. And it is written in Ruby.
10:14	TimMc	The two tools maintain basic config compatibility, which is nice.
10:15	fliebel	… Don't reifies have a type?
10:15	fliebel	TimMc: It's wrapped in some Ruby souse I think. The meat of it is Clojure.
10:21	kumarshantanu	my Leiningen question is here: http://groups.google.com/group/leiningen/browse_thread/thread/fbec0e9ef37a9111/3296ec2ccd087913#3296ec2ccd087913
10:22	kumarshantanu	TimMc: if you'd like to answer the question (link above)
10:32	fliebel	How much faster are types than multimethods?
10:34	raek	Justin Balthrop (ninjudd) is the maintainer of cake. Interview where he mentions why cake was made: http://blog.fogus.me/2010/11/30/take-6-justin-balthrop/
11:02	mattmitchell	i need a function like filter, but to only return the first matching item. is there one that exists?
11:03	ogonzalez	mattmitchell, some
11:03	zmyrgel	some?
11:05	ogonzalez	hmm I think it's quite not the same
11:06	ogonzalez	http://richhickey.github.com/clojure-contrib/seq-utils-api.html#clojure.contrib.seq-utils/find-first
11:07	mattmitchell	perfect thanks!
11:07	ejackson	mattmitchell: does (comp first filter) work for you
11:08	Raynes	mattmitchell: (comp first filter) is a good solution. Since filter is lazy, you aren't really doing any unnecessary computation.
11:08	mattmitchell	ejackson: I think so:
11:08	mattmitchell	(comp first filter)
11:08	mattmitchell	#<core$comp$fn__3642 clojure.core$comp$fn__3642@368bca43>
11:08	mattmitchell	how does that work?
11:09	mattmitchell	oh i think i see
11:09	mattmitchell	oh nice :)
11:09	Raynes	&((comp first filter) (partial = 3) [1 2 3 4 3 5])
11:09	sexpbot	⟹ 3
11:10	ejackson	&((comp first filter) (partial >= 3) [1 2 3 4 3 5])
11:10	sexpbot	⟹ 1
11:10	mattmitchell	... brain working hard ...
11:10	ejackson	hmmm.... that was unexpected
11:11	ejackson	&((comp first filter) even? [1 2 3 4 3 5])
11:11	sexpbot	⟹ 2
11:11	mattmitchell	interesting
11:11	mattmitchell	that's really cool!
11:13	raek	((partial >= 3) 1) is (>= 3 1)
11:13	Raynes	(some even? [1 2 3 4 3 5])
11:13	Raynes	&(some even? [1 2 3 4 3 5])
11:13	sexpbot	⟹ true
11:13	Raynes	&(some #(and (even? %) %) [1 2 3 4 3 5]) ; I do this more often than I'd like to admit.
11:13	sexpbot	⟹ 2
11:14	ejackson	eep
11:15	mattmitchell	Raynes: yeah that's what i was doing before
11:15	ejackson	raek: thanks, I always get that backwards.
11:16	raek	&(letfn [(pick [p?] (fn [x] (when (p? x) x)))] (some (pick even?) [1 2 3 4 5]))
11:16	sexpbot	⟹ 2
11:16	raek	some is a bit weird to use, since it excpects a kind of funtion that you usually don't have
11:16	mattmitchell	raek: and the word
11:16	mattmitchell	oops
11:16	Raynes	raek: I'm so ashamed. ;>
11:17	mattmitchell	and the word "some" seems very much plural
11:17	raek	(except for maps and sets)
11:17	Raynes	raek: I bet there are a few of those in sexpbot and clojail. I'm not even sure that amalloy thinks to change them during his tidy sessions.
11:18	ejackson	mattmitchell: if you prefer the threading style:
11:18	ejackson	&(->> [1 3 5 6 8 10] (filter even?) first)
11:18	sexpbot	⟹ 6
11:18	raek	hadn't thought of using and there...
11:18	raek	neat
11:19	raek	Raynes: ashamed of what?
11:19	mattmitchell	ejackson: so is that actually different from (first (filter even? [1 2 3 4])) ?
11:19	raek	&(macroexpand-1 '(->> [1 3 5 6 8 10] (filter even?) first))
11:19	sexpbot	⟹ (clojure.core/->> (clojure.core/->> [1 3 5 6 8 10] (filter even?)) first)
11:19	Raynes	raek: Using some where I should be using (comp first filter).
11:19	ejackson	no, its just sometimes easier to read as the order of functions appears in the code in the order in which they are execute
11:19	ejackson	rather than inside-out as with the standard syntax
11:20	mattmitchell	ejackson: i see, yeah
11:25	msilverman2	hi guys, what's the easiest way to append something to a list? it looks like conj in lists prepends your data
11:26	Raynes	&(cons 0 '(1 2 3 4))
11:26	sexpbot	⟹ (0 1 2 3 4)
11:26	msilverman2	that's prepending
11:26	ejackson	&(concat '(0 1 2 3) (4))
11:26	sexpbot	java.lang.ClassCastException: java.lang.Integer cannot be cast to clojure.lang.IFn
11:26	Raynes	That was unrelated to your question. Sorry.
11:26	msilverman2	ahh, sorry
11:26	ejackson	&(concat '(0 1 2 3) 4)
11:26	sexpbot	java.lang.IllegalArgumentException: Don't know how to create ISeq from: java.lang.Integer
11:27	Raynes	&(concat '(0 1 2 3) '(4))
11:27	sexpbot	⟹ (0 1 2 3 4)
11:27	ejackson	dammit Raynes !
11:27	ejackson	:P
11:27	Raynes	There isn't really a good way to do that though. You really shouldn't.
11:27	ejackson	agreed, its a bit nasty
11:27	Raynes	If you need to prepend data, you probably should be using vectors.
11:27	Raynes	append*
11:27	Raynes	Forgive me, I didn't sleep much last night. :(
11:28	ejackson	i dunno about that, your trigger finger is pretty Clint Eastwood today :)
11:28	Raynes	:p
11:29	ejackson	or is that all the caffeine ?
11:29	Raynes	I am caffeine free.
11:30	Raynes	I've been caffeine free since last September.
11:30	Raynes	I binged on coke at the Conj and slept about 2 hours the night before the conference started.
11:30	ejackson	oooooooh
11:31	Raynes	Since ninjudd and friends took me to a bar and I was too young to drink, I drank coke so I could still get the teenage rebellion out of my system.
11:31	ejackson	i never manage to go very long w/o, although I'm strictly drip fed on the stuff now, after a similarly binge filled youth
11:31	Raynes	I miss caffeine, but I missed getting sleep at night more.
11:32	dnolen	,(conj [1 2 3 4] 0)
11:32	clojurebot	[1 2 3 4 0]
11:32	dnolen	msilverman2: ^
11:32	ejackson	but that's a vector, he wanted lists, no ?
11:32	msilverman2	it's all good
11:32	msilverman2	we're just using concat
11:32	msilverman2	but is there a better way with lists?
11:32	dnolen	msilverman2: just not that concat is slow - linear in the length of the list.
11:33	dnolen	s/not/know
11:33	sexpbot	<dnolen> msilverman2: just know that concat is slow - linear in the length of the list.
11:33	Raynes	Not really. Lists are not designed for that.
11:33	msilverman2	figured
11:33	dnolen	msilverman2: lists are useful, but is there any reason to not use a vector?
11:33	ejackson	Raynes: an interesting fact for you is that the drinking age in the UK is 18, you should arrange that the conj happens here at the appropriate time :)
11:33	msilverman2	no :) good point
11:33	Raynes	ejackson: Heh. Good to know.
11:34	ejackson	not that I wish to involve myself in corruption, you understand.
11:34	Raynes	I don't have much of an indulging personality.
11:34	ejackson	god, this is an IRC channel, I've probably just got myself on all sorts of FBI lists now.
11:34	thorwil	there's no clojure-contrib 1.2.1 ... using contrib 1.2.0 with clojure 1.2.1 doesn't pose any problems?
11:35	fliebel	Doe anyone happens to have written a 'memoizing' macro? That would bind a vec of functions to memoized versions during the body of the macro.
11:35	Raynes	ejackson: It'll be fine. Maybe a cavity search and the airport or two, but you'll make it.
11:35	Raynes	s/and/at/
11:35	sexpbot	<Raynes> ejackson: It'll be fine. Maybe a cavity search at the airport or two, but you'll make it.
11:36	ejackson	i thought that was standard practice these days ?
11:36	raek	thorwil: yes. tje new stuff in clojure 1.2.1 is just some bug fixes
11:36	Raynes	ejackson: Touché.
12:01	pyr	is it me or are all the clojure/cassandra projects outdated and/or unmaintained ?
12:13	kumarshantanu	fliebel: do you want those functions to be dynamically re-bound?
12:15	fliebel	kumarshantanu: I just need a macro that does (binding [foo (memoize foo) bar (memoize bar)] ~@body)
12:15	kumarshantanu	fliebel: if the functions are known beforehand, then writing one should be straightforward I guess
12:15	fliebel	kumarshantanu: No, they should be passed in.
12:16	fliebel	Still rather straightforward, but I just wanted to know if anyone had one lying around.
12:16	kumarshantanu	fliebel: so you want to pass a vector (variable size) of functions?
12:16	kumarshantanu	oh okay
12:16	fliebel	yea
12:17	fliebel	so it'll involve some looping and concatenating maybe...
12:22	mec	Is there a better way to implement nested-for? https://gist.github.com/901895
12:22	malkomalko	what's the best idiomatic way to filter a seq based on multiple criteria?
12:24	mec	(for [s someseq :when (test1 s) :when (test2 s)] s)
12:24	Raynes	malkomalko: Combinations of and and or.
12:25	Raynes	&(filter #(and (> % 10) (< % 20)) [7 8 9 10 11 12 13 14 15 21 30 45])
12:25	sexpbot	⟹ (11 12 13 14 15)
12:25	malkomalko	yah, that's what I figured, I'm trying to pass in a map to dynamically build up my and list
12:25	malkomalko	just trying to figure out how to do that
12:26	malkomalko	that will be a good start, thanks
12:29	fliebel	Is a sorted map more expensive to insert and delete from, or doesn't it matter because they are both trees anyway?
12:32	raek	fliebel: it probably has log_2 instead of log_32, or something
12:33	fliebel	raek: That would make sense.
12:34	raek	so, 2^n entries would make a tree of depth n
12:49	mattmitchell	is there a fn like select-keys, but instead where you specify the keys you don't want?
12:53	mec	mattmitchell: you could do something like (select-keys m (seq (clojure.set/difference (set keys-you-want) (set (keys m)))))
12:53	mec	but i'd think theres a better way
12:54	mattmitchell	mec: ok excellent
12:54	mec	oh flip those around (clojure.set/difference (set (keys m)) (set keys-dont-want))
12:56	mattmitchell	,(clojure.set/difference #{:id :one :two} #{:two})
12:56	clojurebot	#{:one :id}
12:56	mattmitchell	,(seq (clojure.set/difference #{:id :one :two} #{:two}))
12:56	clojurebot	(:one :id)
12:57	malkomalko	is something like this possible? it seems like % loses context
12:57	malkomalko	https://gist.github.com/15106a3022c4c28d03b6
12:57	mattmitchell	,(select-keys {:id => 1 :one => "1" :two => "skip this"} (seq (clojure.set/difference #{:id :one :two} #{:two})))
12:57	clojurebot	9
12:57	mattmitchell	hmm
12:57	mattmitchell	,(doc select-keys)
12:57	clojurebot	"([map keyseq]); Returns a map containing only those entries in map whose key is in keys"
12:58	mattmitchell	,(select-keys {:id => 1 :one => "1" :two => "skip this"} [:id :one])
12:58	clojurebot	9
12:58	mec	,{:id => 1}
12:58	clojurebot	java.lang.RuntimeException: java.lang.ArrayIndexOutOfBoundsException: 3
12:59	mattmitchell	why is that?
12:59	mec	,(select-keys {:id 1 :one "1" :two "skip this"} [:id :one])
12:59	clojurebot	{:one "1", :id 1}
12:59	mattmitchell	omg no! sorry, i'm mixing in my ruby :(
12:59	mattmitchell	i switch back and forth all day eh eh
13:00	mattmitchell	,(select-keys {:id 1 :one "1" :two "skip this"} (seq (clojure.set/difference #{:id :one :two} #{:two})))
13:00	clojurebot	{:id 1, :one "1"}
13:00	mattmitchell	there we go!
13:00	mec	instead of difference i would do (apply disj (set (keys m)) keys-you-dont-want) or if you konw the keys just (disj (set (keys m)) key1 key2)
13:01	mattmitchell	,(doc disj)
13:01	clojurebot	"([set] [set key] [set key & ks]); disj[oin]. Returns a new set of the same (hashed/sorted) type, that does not contain key(s)."
13:07	mec	malkomalko: im not sure what you're trying exactly but doseq always returns nil, i think you want for. Also #(and (for ...)) wouldnt work you need something like #(every? identity (for ...))
13:07	malkomalko	I'm trying to build in a list to of statements to filter on based off a map
13:08	malkomalko	wow, awesome grammar...
13:08	mec	lol
13:08	mec	can you give me an example of the result?
13:12	Raynes	mattmitchell: Sounds like you lead a very complicated existence.
13:12	mattmitchell	Raynes: why do you say that?
13:13	Raynes	You switch between Clojure and Ruby all day long and get the two mixed up. Sounds like a confusing lifestyle. :p
13:14	mec	I dont think its too hard ;p i cought myself writing lua style maps once
13:14	mattmitchell	Raynes: seriously, tell me about it. we just started using clojure a few months ago.
13:14	mattmitchell	and now half of our stuff is in clojure, half in ruby
13:16	ejackson	yeah, its the same for me. I now get annoyed with python etc when I can't do things like make lists keys in maps.
13:19	mattmitchell	eh eh. sometimes when i switch back to ruby and see "if(xxx)", i just stare at it ??? it takes me a minute to remember that it's ruby and there is no prefix notation
13:21	malkomalko	hey mec... what's the diff between (filter #(every? identity (for...)..) vs (filter #(every? (for ..)..)
13:22	fliebel	malkomalko: unified diff?
13:22	fliebel	ANyway, I don;t think the later is valid
13:22	pdk	(doc identity)
13:22	clojurebot	"([x]); Returns its argument."
13:23	technomancy	if you're using for anyway, you should use the :when clause rather than having a sepraate filter call
13:23	pdk	i think there's something wrong with the formatting in both though
13:23	malkomalko	this worked
13:23	malkomalko	https://gist.github.com/15106a3022c4c28d03b6
13:23	amalloy	Raynes: i did write raek's "pick" in amalloy/utils, though i called it verify. i haven't ported any of that to sexpbot yet though
13:24	malkomalko	but i just feel like I'm not doing it the best way
13:25	amalloy	mattmitchell: i disagree about the word "some". i agree the function "should" act like (comp first filter), but i remember using "some" in the same context as "there exists" back in school. "some positive x", etc
13:25	pdk	there's no function some that uses it in that sense though
13:31	mattmitchell	amalloy: i see what you mean. This example... returns true, which is what I would expect: (some even? [2 3 4 5 6])
13:32	amalloy	mattmitchell: right. i kinda wish it returned 2: "find some even number from this list"
13:32	amalloy	as do you
13:33	kephale00	yeah perhaps some as is should actually be named some?
13:33	mattmitchell	amalloy: yeah 2 makes sense too. i originally was looking for something like ruby's "detect" -> http://www.ruby-doc.org/core/classes/Enumerable.html#M001485
13:33	mattmitchell	detect returns the first item in the collection when the "predicate" is true
13:34	kephale00	, (some #(if (even? %) %) [2 3 4])
13:35	clojurebot	2
13:35	kephale00	i retract my statement about renaming some, its just how you use it
13:36	amalloy	kephale00: just a sketch, i know, but it's generally bad form to use a single-branch if. prefer when (in this case, "and" would work as well)
13:36	kephale00	amalloy: noted and appreciated
13:36	pdk	and standing in for when is kinda hackish
13:39	amalloy	pdk: meh. and is designed for short-circuiting on purpose. in languages lacking a when construct, you might well write "divisible = y != 0 && x % y == 0"
13:40	kephale00	i've run into and being used in such situations in common lisp a number of times
13:40	kephale00	wow.. its confusing to read that without denoting AND in some way
13:41	mec	malkomalko: this may be better, but I think it can be simplified further, im just not sure how https://gist.github.com/gists/fd02f373dd819b5e4536/edit
13:41	amalloy	kephale00: yes, not a well-written example :P
13:42	amalloy	haha github's 500 page is adorable
13:43	mec	malkomalko: sorry this one https://gist.github.com/fd02f373dd819b5e4536
13:45	amalloy	mec: i missed the start of that discussion, i guess. what is this code trying to do?
13:49	mec	amalloy: no idea
13:49	amalloy	haha
13:49	mec	malkomalko: ok this is deffinitly the one https://gist.github.com/fd02f373dd819b5e4536
13:53	fliebel1	What is this supposed to mean? RetryEx clojure.lang.LockingTransaction http://pastebin.com/11xTUfKn
13:54	hiredman_	fliebel1: means your code is trying to dos the stm
13:54	hiredman_	"pleases stop"
13:59	fliebel1	hiredman_: Haha, sure… I know what is the problem idk.
14:05	fliebel1	More weird errors, this is what I get upon closing my Swing window: http://pastebin.com/UjdhDhcX
14:06	ieure	Is there a decent XML/HTML parser for Clojure similar to lxml for Python?
14:06	fliebel1	Note that there is none of my nses in there, and a few mentions of Leiningen.
14:07	fliebel1	ieure: I think there is a lot of XML stuff in Java, and some in clojure.contrib as well.
14:07	kumarshantanu	hi, can anybody here tell me how does leiningen set the classpath (to include project sources)? e.g. for "lein test" or "lein repl"
14:07	amalloy	kumarshantanu: less `which lein` - it's fairly straightforward iirc
14:08	ieure	fliebel1, Yeah, what I’m really after is a single lib that lets me use the same code to parse HTML and XML.
14:08	fliebel1	ieure: Oh, like tagsoup?
14:08	amalloy	ieure: tagsoup
14:08	technomancy	kumarshantanu: see the leiningen.classpath namespace
14:09	ieure	fliebel1 / amalloy, Looks like exactly what I want.
14:09	ieure	Thanks.
14:09	ieure	amalloy, BeautifulSoup is a Python library.
14:09	amalloy	yeah, i looked it up
14:09	amalloy	again :)
14:09	ieure	It’s crazy handy.
14:10	amalloy	ieure: i think tagsoup was first
14:13	fliebel1	Grr, does anyone know why I might possibly get IndexOutOfBoundsException when closing a Swing window?
14:14	fliebel1	amalloy: I have the same.
14:14	kumarshantanu	amalloy: thanks, yes the script includes both "src" and "test" folders in classpath
14:14	fliebel1	But worse, I forget about one completely and end up on the wrong page, not remembering the other one.
14:16	kumarshantanu	technomancy: yes, I can see the classpath using leiningen.classpath/classpath -- but surprisingly, any attempt to (require (symbol "foo.valid-ns")) and (resolve (symbol "foo.valid-ns/bar")) fails - returns nil
14:17	kumarshantanu	I am trying to do this inside a leiningen plugin (that a host project uses)
14:17	technomancy	that is the classpath that eval-in-project will use to run any code that needs access to the project's dependencies and/or source
14:18	technomancy	kumarshantanu: HACKING.md may be helpful here
14:18	kumarshantanu	technomancy: I am doing this inside eval-in-project -- is that a right thing to do?
14:19	technomancy	yeah, if you need access to the project source, you need to run inside eval-in-project
14:22	kumarshantanu	technomancy: ah, seems I found a clue -- actually i am declaring `:eval-in-leiningen true` in the host project, because unless I do that leiningen.compile isn't available to the plugin
14:23	kumarshantanu	and HACKING.md seems to say that if I set `:eval-in-leiningen true` then that will be an exception and therefore (I guess) sources will not be included in the classpath (!!)
14:28	technomancy	kumarshantanu: you can't have code eval both in leiningen's process and the project's. you have to pick one.
14:32	kumarshantanu	technomancy: not sure if I followed that - I want to have the host project's deps+sources on the classpath (like test, repl) and want to eval-in-project from the plugin at the same time. That seems to require that I declare `:eval-in-leiningen true` (because unless I do that, leiningen.compile namespace isn't available to the plugin)
14:34	kumarshantanu	I guess I am missing something obvious, but not sure what
14:52	fliebel1	What is the `~@ trickery for turning a supplied symbol into a qualified one? `(foo ~bar) -> (some.ns/foo some.other.ns/bar) It works without it, but I suppose it's cleaner to have them qualified?
14:54	pdk	,`x
14:54	clojurebot	sandbox/x
14:54	amalloy	fliebel1: ##(let [supplied bar] `(foo `~supplied))
14:54	sexpbot	java.lang.Exception: Unable to resolve symbol: bar in this context
14:54	amalloy	&(let [supplied 'bar] `(foo `~supplied))
14:54	sexpbot	⟹ (clojure.core/foo clojure.core/supplied)
14:54	amalloy	dangit. maybe not
14:55	fliebel1	amalloy: Yea, I want to get whatever 'bar points to
14:56	fliebel1	&(let [x 'y y 1] `(~(resolve x)))
14:56	sexpbot	java.lang.SecurityException: You tripped the alarm! resolve is bad!
14:56	fliebel1	,(let [x 'y y 1] `(~(resolve x)))
14:56	clojurebot	(nil)
14:56	fliebel1	oh
14:59	amalloy	fliebel1: resolve doesn't get access to locals (nothing does)
15:01	amalloy	incidentally, trying to manually namespace-resolve symbols supplied by the user sounds like a bad idea. why do you want it?
15:07	msilverman2	is there anyway to run a single deftest with lein?
15:08	technomancy	msilverman2: you can use test selectors; see the tutorial
15:09	technomancy	kumarshantanu: I see. you can't change the classpath of leiningen itself, and a plugin runs inside the leiningen process.
15:09	msilverman2	thanks
15:13	fliebel1	amalloy: If it's a bad idea, I don't wan it. I just thought using unqualified symbols was bad practice most of the time. But thinking about it, symbols supplied by the user should be 'clean'
15:13	msilverman2	technomancy: I got this after following the tutorial: Could not locate robert/hooke__init.class or robert/hooke.clj on classpath:
15:14	kumarshantanu	technomancy: sorry for the repeated ping! I located the problem (of not resolve'ing a symbol) was in my own code -- it works for me now. Thanks so much!
15:14	amalloy	fliebel1: right. symbols supplied by the user should be left alone unless your intent is to transform them. they don't need to be qualified, because in the user's scope they already resolve to something
15:15	technomancy	msilverman2: oy, I need to update the tutorial about that. you need to add [robert/hooke "1.1.0"] to your :dependencies in project.clj for that to work.
15:15	technomancy	kumarshantanu: aha; great.
15:15	msilverman2	thanks
15:15	msilverman2	what does that package do?
15:16	technomancy	msilverman2: all manner of wonderful hackery
15:16	msilverman2	lovin it...
15:16	technomancy	basically an extension mechanism for functions you don't have controll over
15:16	technomancy	https://github.com/technomancy/robert-hooke
15:17	technomancy	sorta like monkeypatching, but a little safer
15:20	fliebel1	Can I use Java methods like one can use methods in Python? I mean, (someclass/method otherclass arg arg)
15:21	fliebel1	I am having trouble shaping a piece of api in a easy and extensible manner.
15:24	fliebel1	In Python, you have explicit this/self, which allows you to apply methods of one class to another. Since methods in deftypes and such also have the self, I was wondering if I could reuse them that way.
15:30	amalloy	no
15:30	fliebel1	okay
15:31	amalloy	but i think extend-type allows you to specify a map protocol-functions to implementations
15:31	amalloy	so you can reuse the clojure functions
15:31	fliebel1	yea… Thinking about it…
15:31	amalloy	ah, i guess you have to use the raw extend function
15:32	fliebel1	okay
16:31	thorwil	(type body) tells me that body is a com.google.appengine.api.datastore.Text
16:31	thorwil	but (isa? body com.google.appengine.api.datastore.Text) doesn't seem to be true
16:34	technomancy	thorwil: yeah, that's confusing. you want instance? instead.
16:35	technomancy	isa? isn't really about isa?
16:35	thorwil	what's the right way to test for class membership, then?
16:37	thorwil	oh. not clear evena fter reading the doc
16:37	dnolen	,(doc isa?)
16:37	clojurebot	"([child parent] [h child parent]); Returns true if (= child parent), or child is directly or indirectly derived from parent, either via a Java type inheritance relationship or a relationship established via derive. h must be a hierarchy obtained from make-hierarchy, if not supplied defaults to the global hierarchy"
16:38	technomancy	,(doc instance?)
16:38	clojurebot	"([c x]); Evaluates x and tests if it is an instance of the class c. Returns true or false"
16:39	thorwil	yeah, now in contrast it's very clear :)
16:40	thorwil	i'm testing with a java.lang.String
16:40	thorwil	trying instance? gives me java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Class (NO_SOURCE_FILE:0)
16:40	dnolen	thorwil: reverse arg order.
16:41	thorwil	thanks
16:41	thorwil	looks like it's getting time for me to log off soon ;)
17:04	kephale00	I'm not sure what this stems from. I am using lein to make an uberjar within a function that is called from -main I do an EVAL on a list representation of a function call (J 3 4) which is a function defined inside my core.clj. This fails when I call it from the uberjar. When I run it in swank I don't get the issue.
17:04	kephale00	I resolved this by calling (use 'myns.core) at the start of my -main, but really weird.
17:06	kephale00	errr… not calling lein from a function
17:07	kephale00	there should be a period after uberjar
17:11	amalloy	kephale00: a lot of the calling environment's context doesn't get passed on to eval. i know eval doesn't have access to lexical bindings, for example. i thought it got the benefit of your use/require forms, but i wouldn't be astonished to find out it didn't
17:13	kephale00	amalloy: aha. the thing that caught me off guard was the difference between the uberjar and swank, but maybe that is because when calling the function in swank I am already in the namespace or something along those lines. The thing is that everything that caused the issue was contained within the core.clj
17:13	kephale00	but all is well… until i find something else to break
17:14	amalloy	generic warning about eval being evil
17:14	kephale00	heh
18:29	Somelauw	Okay, I am install cake
18:29	Somelauw	I did sudo ln -s bin/cake /bin/cake
18:29	Somelauw	And tried typing cake but nothing happened.
18:32	sritchie	,(not (not-any? #{:jobtracker :namenode} [:jobtracker :slavenode]))
18:33	clojurebot	true
18:33	sritchie	is there a version of this with contains? that will return a bool?
18:33	amalloy	Somelauw: you installed a relative symlink in the wrong place
18:34	amalloy	now /bin/cake is a file saying "look in ./bin/cake", that is /bin/bin/cake
18:34	sritchie	or! is it idiomatic to wrap this in a predicate like (defn master? [roles] ... and trust that the user will use it as a predicate?
18:35	amalloy	sritchie: huh?
18:35	sritchie	I'm writing a predicate that will check if any item in the supplied collection can be found in that set
18:35	amalloy	are you looking for ##(some #{:a :b} [:c :a])?
18:36	sexpbot	⟹ :a
18:36	sritchie	amalloy: yup, that's great. my other question was, is there a function like some that returns an explicit boolean
18:36	Somelauw	So, I should give an absolute path?
18:36	amalloy	if you really-really want the user to only get out a boolean instead of a truthy-thing, you can cast to boolean
18:37	amalloy	Somelauw: if you're going to install it in an absolute place, yeah
18:37	amalloy	i just put cake in ~/bin, though
18:37	sritchie	okay, but it's idiomatic to trust that a function called "master?" is going to return a truthy value, not necessarily a bool
18:37	amalloy	eg ##(boolean (some #{:a :b} [:c :a]))
18:37	sexpbot	⟹ true
18:38	amalloy	(def master? (comp boolean (partial some #{:namenode :jobtracker}))) for some amusing point-free nonsense
18:39	sritchie	point free or bust
18:40	amalloy	brehaut: in haskell that would be something like... master = boolean . some #{:foo :bar}, yes? (imagining that haskell has clojure's functions, anyway)
18:40	brehaut	yup
18:40	amalloy	woo
18:41	brehaut	plus maybe a type hint to dodge the monomorphism restriction (sigh)
18:41	amalloy	@$#@?
18:41	Somelauw	Okay, I put it in my bin as well.
18:42	brehaut	amalloy: cat trouble?
18:42	amalloy	brehaut: no, just you
18:42	amalloy	as in, "what is this monomorphism nonsense"
18:42	Somelauw	I tried running "cake repl" and now it is downloading something.
18:42	amalloy	Somelauw: sounds good
18:44	brehaut	amalloy: oh right. its a think in the haskell type system that was added to simplify some type errors early on and that is now regretted; some instances of generic types are only allowed to have a single morphism or specific type unless you go out of you way to ok it with the compiler. its dumb.
18:44	brehaut	amalloy: in particular you hit it a lot with point free stuff in the repl
18:45	Somelauw	And now it is printing a lot of resource not found messages.
18:45	amalloy	brehaut: that sounds well beyond my superficial knowledge of haskell
18:45	brehaut	amalloy: heres a fun quote from the haskell wiki "The monomorphism restriction is probably the most annoying and controversial feature of Haskell's type system. All seem to agree that it is evil, but whether or not it is considered a necessary evil depends on who you ask."
18:45	brehaut	http://www.haskell.org/haskellwiki/Monomorphism_restriction
18:47	Somelauw	But the repl is working now
18:48	amalloy	confirmed: reading that page causes my brain to bubble, but no information is imparted
18:49	brehaut	amalloy: that summarises it pretty well ;)
19:10	ieure	Hm, was #^{…} the old reader macro for metadata?
19:10	amalloy	yes
19:10	amalloy	it still works (more or less) but don't use it in new code
19:10	amalloy	ieure: ^
19:10	ieure	Yeah. I just saw it in clj-http and wasn’t sure if that was the case or not.
19:11	ieure	Wanted to make sure I understood what was going on, since there’s no mention of it on http://clojure.org/reader
19:11	gigamonkey	This may be silly but can the dispatch function in a multi-method itself be a multi-method?
19:12	ieure	Multimethods all the way down.
19:12	gigamonkey	Great.
19:12	amalloy	gigamonkey: yes. sounds silly but i'm sure there's some reason for it somewhere
19:12	ieure	gigamonkey, I have no idea, really.
19:12	ieure	Try it and find out!
19:12	gigamonkey	ieure: heh. I haven't even got Clojure installed yet.
19:12	gigamonkey	Lame, I know.
19:13	ieure	gigamonkey, Gotta start somewhere.
19:14	gigamonkey	Bah, this is where I hate that Clojure is built on top of Java. Maven, Ant, blech.
19:14	brehaut	gigamonkey: are you trying to install from source?
19:15	ieure	gigamonkey, It is one of the best and undoubtedly the worst thing about it.
19:15	gigamonkey	brehaut: I think I'm going to skip that for the reasons just mentioned. ;-)
19:15	ieure	gigamonkey, I recommend that you start by installing Leiningen, rather than Clojure.
19:15	ieure	https://github.com/technomancy/leiningen
19:15	brehaut	gigamonkey: the reasons you mentioned are exactly the reasons you never have to install from source ;)
19:16	gigamonkey	I would not have guessed that "a build tool for X" can be installed "rather than" X
19:17	ieure	gigamonkey, Yes, well. Lisp & JVM make for strange bedfellows.
19:18	ieure	The nature of Clojure (JVM-based, young, relatively active development) mean that you really want to stick the appropriate JAR files into your workspace per-project rather than dicking around with installing stuff on the system.
19:18	ieure	And Leiningen is the tool which makes that not suck.
19:18	Oabl	It's even more fun with other dialects (i.e. building SISC is a pita).
19:21	Somelauw	I think that because clojure being build on top of java makes it practical.
19:21	gigamonkey	Somelauw: no doubt. However I don't actually care about that. ;-)
19:21	gigamonkey	Do I need a special version of SLIME for use with Clojure or is stock SLIME okay?
19:21	cemerick	Indeed; it being on the JVM means it'll be deployed far wider than probably any other lisp (if it isn't already).
19:22	amalloy	gigamonkey: get clojure-mode.el
19:22	ieure	gigamonkey, I have the latest installed from ELPA, works fine.
19:22	ieure	And yeah, clojure-mode.
19:22	gigamonkey	ELPA?
19:22	technomancy	gigamonkey: newer slimes break with Clojure; the version that worsk can be got via package.el or at https://github.com/technomancy/slime
19:22	amalloy	i think stock slime is probably okay, but clojure-mode.el has some nice stuff in it
19:22	ieure	gigamonkey, JFGI
19:23	amalloy	$google elpa
19:23	sexpbot	First out of 83900 results is: Welcome to ELPA
19:23	sexpbot	http://tromey.com/elpa/
19:23	technomancy	gigamonkey: but if a sufficiently-motivated CL-head could bring swank-clojure up to date with the latest slime developments I'd be happy =)
19:23	amalloy	wonder if that's right
19:23	amalloy	$google elpa emacs
19:23	sexpbot	First out of 930 results is: Welcome to ELPA
19:23	sexpbot	http://tromey.com/elpa/
19:23	amalloy	whew
19:23	gigamonkey	technomancy: how well understood are the issues that need fixing?
19:24	technomancy	gigamonkey: not very, unfortunately. the author of swank-clojure went MIA a couple years ago, and I took over in maintenance mode, but it's kind in a "don't poke it to hard" state.
19:24	technomancy	my knowledge is pretty cursory
19:24	technomancy	*too hard
19:25	gigamonkey	ieure: of course the "latest" SLIME in ELPA doesn't seem, in fact, to be the latest SLIME.
19:26	kephale00	gigamonkey: i think we're supposed to use marmalade now
19:27	technomancy	gigamonkey: the problem is the slime devs don't seem to value stable releases, so publishing via package.el was my way of saying "this version here; we're calling that a release" and getting off the cvs treadmill
19:30	Somelauw	What is the best way to return multiple values?
19:30	ieure	Somelauw, Depends on what you need to do with them.
19:30	brehaut	technomancy: OT: did see that clj-time got a non-snapshot the other day?
19:30	ieure	Somelauw: A list, vector, or map are fine. Just use whatever’s appropriate for the conventions in the callers.
19:30	Somelauw	Okay, I have a list and I would like to remove and return a random element from that list.
19:30	technomancy	brehaut: whew; finally
19:31	brehaut	technomancy: weevejester and mmcgrana to the rescue.
19:31	Somelauw	It would be convenient to have syntax like (def [a b c] [1 2 3]) or something to easily return multiple values.
19:31	gigamonkey	kephale00: marmalade instead of what?
19:32	amalloy	gigamonkey: i'm worried it might have been a pun on the word slime
19:32	kephale00	gigamonkey: oh, you mentioned elpa, i figured you were using that instead of marmalade
19:32	amalloy	Somelauw: that syntax exists for let. you don't often want to def a zillion things wholesale
19:32	Somelauw	Since lists are immutable, I thought I should return both the removed element and the list with that element removed.
19:33	amalloy	&(let [[a b c] (range)] b)
19:33	sexpbot	⟹ 1
19:33	Oabl	Somelauw, how about... (defn foo [] [(do something) (another thing)]) (let [[a b] (foo)] (...))
19:34	ieure	Somelauw, I’d make sure that you _need_ to return both first. "I thought this would be a good idea" is a great way to write a bunch of code you don’t really need.
19:34	ieure	That said, you’re going to find some nice features of Clojure if you do.
19:34	Somelauw	lets are fine too, but it is also usefull to be able to do the same with def, probably.
19:34	amalloy	haha probably
19:35	amalloy	Somelauw: you might find https://github.com/amalloy/amalloy-utils/blob/master/src/amalloy/utils/seq.clj#L74 handy if you want to take random elements out of a list
19:35	gigamonkey	technomancy: do you know if there was ever any attempt to get clojure-swank included in the main SLIME?
19:36	technomancy	gigamonkey: there was a long time ago. they might be more open to it now that Clojure has matured a bit. I don't have the cycles to push for that myself though; I'm just keeping up the status quo.
19:36	amalloy	Somelauw: in practice it really isn't useful. if you want to do something like that you'll want to do some processing on the elements anyway; and then you end up using a macro that expands into (do (def x (some-function-of 1)) (def y (some-function-of 10)))
19:36	technomancy	plus I'm too old to have the patience for CVS =)
19:37	ieure	technomancy, Slime is in CVS? Savages.
19:37	technomancy	ieure: it's true.
19:38	Somelauw	amalloy: lazily shuffling a list of elements is also a cool idea, thanks.
19:39	gigamonkey	technomancy: yeah, that's kind of astounding to me.
19:40	amalloy	someone get out the chloroform, and run cvs2git while the slime devs are out of commission
19:46	technomancy	gigamonkey: essentially every time someone mentions swank-clojure, I make thinly-veiled attempts to pass off maintainership. no luck so far. =)
19:46	amalloy	technomancy: i cloned swank-clojure! sadly by the time i got around to looking at it i forgot what i wanted to fix
19:47	technomancy	amalloy: this does not disqualify you from potential maintainership, just so you know.
19:48	amalloy	technomancy: yeah, i'm keeping my teflon coat on just in case you try to stick me with it
20:31	gigamonkey	technomancy: well, I was a long-ago hacker on SLIME and do grok Common Lisp. So maybe if I get into Clojure I'll take a look. But doubtful.
20:32	technomancy	gigamonkey: I know, I've read the book. no worries though; I'm not really expecting anyone to take me up on it =)
20:33	technomancy	it's really only an issue for people who want to hack CL and Clojure simultaneously, which is a pretty small minority. stumpwm users mostly, I figgure.
20:37	gigamonkey	Yes, if/when that population is larger, it'll probably get sorted.
23:13	hboon	Can someone help take a look at a 12 line macro using try-catch, would like some help with it - https://gist.github.com/902956
23:16	ataggart	the ~name emits a namespaced symbol, which isn't allowed on the lefthand side of the let bindings
23:16	ataggart	wait, no
23:16	ataggart	how are you calling it?
23:16	hboon	the syntax itself is right (and taken from redis-clojure)
23:17	hboon	it's called from another macro
23:17	hboon	i would like to make it not call the second release-connection (the one in finally) if there's an exception (i.e. if the catch is triggered)
23:18	hboon	ie. in procedural languages, you set a flag in catch and check for it in finally
23:18	ataggart	move the one in finally to immediately after ~@body
23:19	ataggart	that'll work so long as it doesn't also throw an exception
23:19	hboon	this macro will be used in a different ns, in case that matters (because I was having problem trying to use (def flag true), etc
23:20	hboon	ok. sounds like that ought to work. Excellent!
23:20	hboon	well, just for curiosity sake.. how would I do it if it does throw an exception and catch wasn't catching Exception, but a subclass?
23:21	hboon	what's the functional equivalent of doing it instead of a global flag? (heck I can't even figure out to use a global flag since it's in a macro)