#clojure – 2011-03-03

2011-03-03

00:31	ossareh	technomancy: have you any thoughts / experiences about how hard / easy it would be to get a git revision value in a hooke?
00:41	ossareh	hm, seems jgit can be wrapped reasonably easily.
00:41	technomancy	ossareh: those seem pretty orthogonal to me
00:41	ossareh	well... I want to be able to load a version number into my output html and I figured git version would be the most helpful
00:42	ossareh	zz my english is sucking right now :/
00:42	ossareh	i guess my question was more like - have you done this / know of a project doing this.
00:44	technomancy	the pom.xml that comes with every lein-generated jar has git revision info in it
00:45	ossareh	OK - that is good. So accessing that from the runtime is just a case of read/parse the pom.xml?
00:48	technomancy	yeah, should work with clojure.java.io/resource
00:49	tomoj	mine doesn't appear to have git revision info
00:50	tomoj	maybe I misunderstood
00:51	ossareh	technomancy: ah, and there is the magic - I've realised that through my learning curve with clojure I learn about a new set of language features every 6 weeks or so - I then spend 6 weeks crow baring them into a solution that is usually already handled somewhere in the stdlibs...
01:03	technomancy	tomoj: lein pom has no git info?
01:04	tomoj	`lein pom && grep git pom.xml` gives only " https://github.com/technomancy/leiningen -->"
01:05	technomancy	it's actually able to read files straight out of .git/; you don't even need git installed to do it
01:05	technomancy	crazy
01:05	technomancy	tomoj: is the project OSS?
01:05	tomoj	oh, is it only supposed to work when the project root is the git root?
01:05	tomoj	naturally, I suppose
01:05	technomancy	yeah, I guess it might not work for a project that's nested
01:05	tomoj	nope
01:06	tomoj	I tried to argue for multiple repos but wound up with one mega-repo into which all my various projects go :(
01:06	technomancy	ah, bummer
01:07	tomoj	of course in this case it doesn't matter anyway, I'm not publishing the pom and would want to strip any git information that did make it in..
03:28	bairespace_	,(defn <- [& args] (reduce #(%1 %2) args))
03:28	clojurebot	DENIED
03:29	bairespace_	,(+ 2 2 2 2)
03:29	clojurebot	8
03:40	bairespace_	,(source core/->)
03:40	clojurebot	java.lang.Exception: Unable to resolve symbol: source in this context
03:41	bairespace_	,(doc ->)
03:42	clojurebot	"([x] [x form] [x form & more]); Threads the expr through the forms. Inserts x as the second item in the first form, making a list of it if it is not a list already. If there are more forms, inserts ...
03:47	bairespace_	,[0 1 2 #{3 4 5}] (-> {:a {:b 3}} :a :b)
03:47	clojurebot	[0 1 2 #{3 4 5}]
03:53	bairespace_	,(([0 1 2 #{3 4 5}] (-> {:a {:b 3}} :a :b) 4)
03:53	clojurebot	EOF while reading
03:55	bairespace_	,([0 1 2 #{3 4 5}] (-> {:a {:b 3}} :a :b))
03:55	clojurebot	#{3 4 5}
04:03	bairespace_	,[]
04:04	clojurebot	[]
04:04	bairespace_	,{}
04:04	clojurebot	{}
04:04	bairespace_	,#{}
04:04	clojurebot	#{}
07:08	clgv	&(macroexpand-1 '(when-let [bla blubb] haha hoho))
07:08	sexpbot	⟹ (clojure.core/let [temp__3589__auto__ blubb] (clojure.core/when temp__3589__auto__ (clojure.core/let [bla temp__3589__auto__] haha hoho)))
07:09	clgv	why are there two let expressions involved? wouldn't one be sufficient?
07:42	raek	&(macroexpand-1 '(when-let [[foo bar] blubb] haha hoho))
07:42	sexpbot	⟹ (clojure.core/let [temp__3589__auto__ blubb] (clojure.core/when temp__3589__auto__ (clojure.core/let [[foo bar] temp__3589__auto__] haha hoho)))
07:44	raek	clgv: I think it is done this way make sure that the expression is only evaluated once, even when combined with desctructuring
07:44	clgv	raek: thx. hoeck already gave me a similar hint :)
07:57	fogus`	Whoa! Clojure's juxt is FP's []! That is all
07:58	__name__	FP?
07:59	__name__	$source juxt
07:59	sexpbot	juxt is http://is.gd/8fgyhN
08:01	fogus`	http://en.wikipedia.org/wiki/FP_(programming_language)
08:14	clgv	what's that supposed to mean? java.lang.IllegalArgumentException: recur arg for primitive local: sum must be matching primitive
08:15	clgv	I get it in this line: (loop [complist (second group-complist), cdf (transient []), sum (double 0.0)]
08:17	raek	clgv: what does the recur form lool like?
08:17	mduerksen	clgv: is the third argument in in your recur form a double?
08:18	clgv	it should be. it is like: new-sum (+ sum (f x)) and new-sum is in the recur
08:19	AWizzArd	http://www.classnamer.com/
08:20	clgv	AWizzArd: "SecureGirlfriendStream" roflmao.
08:24	mduerksen	clgv: if (f x) doesn't return a double, then + won't return a double as well afaik
08:25	clgv	mduerksen: ok, but (f x) is a method specified in a protocol. can I type hint its return type?
08:25	mduerksen	i'm not sure about that. i guess it also depends on the clojure version
08:25	clgv	1.2
08:26	clgv	well otherwise I surround it with (double ...)
08:26	mduerksen	you could find out with (class (f x))
08:27	clgv	I know that it should return a double since I wrote it myself
08:27	clgv	but I don't know how to tell the compiler that this protocol method will return a double
08:27	raek	hrm, I thought this primitive stuff was new for 1.3...
08:28	clgv	raek: not everything
08:30	Chousuke	functions can't return primitives in 1.2 IIRC :/
08:31	clgv	but there is the fibonacci example that is said to be valid in 1.2
08:31	Chousuke	http://dev.clojure.org/display/doc/Enhanced+Primitive+Support this describes 1.3
08:32	clgv	oh ok. damn :(
08:32	clgv	hmm I thought I read something related to 1.2 in a blog entry on ^:static
08:32	clgv	is ^:static also 1.3?
08:34	cemerick	IIRC, ^:static became a no-op with the recent var changes
08:34	cemerick	a no-op and unnecessary, that is
08:40	clgv	ok. probably (double ...) will work then
09:00	clgv	&(doc empty?)
09:00	sexpbot	⟹ "([coll]); Returns true if coll has no items - same as (not (seq coll)). Please use the idiom (seq x) rather than (not (empty? x))"
09:01	clgv	&(empty? nil)
09:01	sexpbot	⟹ true
10:36	flatt	should I be using eval here: (defn [x] (eval (doto (SomeClass.) (.doStuff x))))? can I (or should I) pull it off with defmacro instead?
10:38	raek	flatt: you very rarely need to use eval.
10:38	raek	flatt: why not (defn [x] (doto (SomeClass.) (.doStuff x)))
10:38	flatt	oh, wait, that was over-simplified.
10:40	flatt	(defn [& args] (eval `(doto (SomeClass.) ~(list '.doStuff ~args))))
10:40	Chousuke	flatt: why would you do that with a function?
10:40	Chousuke	one big problem with eval is that it can't access locals
10:41	Chousuke	so all you can pass to your function are symbols that name globals.
10:41	Chousuke	or literals
10:41	raek	flatt: ah, so you want something like apply, but for methods?
10:41	flatt	oh, then then eval doesn't help there.
10:42	flatt	imagine variable number of forms in the body of doto, depending on what args are supplied
10:44	bennylu	how to use ns-publics? (ns-publics 'some-ns)
10:44	bennylu	=> #<ClassCastException java.lang.ClassCastException: clojure.lang.Var cannot be cast to clojure.lang.IObj>
10:44	bennylu	i want to retrive all the functions in the namespace with a certin type ..
10:44	raek	,(ns-publics 'clojure.core)
10:44	clojurebot	{sorted-map #'clojure.core/sorted-map, read-line #'clojure.core/read-line, re-pattern #'clojure.core/re-pattern, keyword? #'clojure.core/keyword?, val #'clojure.core/val, chunked-seq? #'clojure.core/...
10:46	bennylu	, (ns-publics 'clojure.xml)
10:46	clojurebot	{content-handler #'clojure.xml/content-handler, stack #'clojure.xml/stack, attrs #'clojure.xml/attrs, element #'clojure.xml/element, tag #'clojure.xml/tag, startparse-sax #'clojure.xml/startparse...
10:46	raek	bennylu: it looks like the exception is from the code that uses the value of your (ns-publics 'some-ns) call
10:48	raek	flatt: it is certainly possible to do that with a macro, but dependending on what you know about the methods (e.g. arity) you could possibly implement it as an ordinary function (which is preferred if possible)
10:48	bennylu	i am calling it directly from the repl..
10:49	flatt	raek: I see, thanks.
10:51	TimMc	bennylu: Are you bennylut?
10:51	raek	bennylu: what does the stack trace look like?
10:52	raek	bennylu: also, does this happen for all namespaces? for instance, does (ns-publics 'clojure.core) work for you?
11:03	perkinsc	,(clojure-version)
11:03	clojurebot	"1.2.0"
11:09	sattvik	flatt: If you know the number of arities you will be working with, you can do something like:
11:09	sattvik	,(let [invoker (fn ([a] (. Integer valueOf a)) ([a b] (. Integer valueOf a b)))] (apply invoker ["100" 2]))
11:09	clojurebot	4
11:09	pyr	hi
11:10	sattvik	The only other non-macro approach I can think of is using Java's reflection APIs.
11:10	pyr	it's not clear to me if there's a way to kill agents forcibly
11:10	pyr	i'm using agents with await-for
11:10	pyr	if an agent returns false from await-for
11:11	pyr	do I need to kill it or will the thread be available for a new agent ?
11:11	TimMc	$findfn [1 2 3] 3 4 [1 2 4]
11:11	sexpbot	[]
11:12	chouser	pyr: I don't think there's any good way to forcibly kill an agent.
11:13	pyr	ok
11:15	clgv	where do I get clojure-contrib 1.3.0 alpha 4?
11:49	gtrak	how do you guys do a find-usages?
11:53	sattvik	find-usages?
11:54	gtrak	yea
11:55	TimMc	Like, all references to a var in a project?
11:55	TimMc	I generally grep. -.-
11:56	gtrak	I guess that's pretty simple :-)
11:57	dakrone	b
11:58	amalloy	gtrak: slime has a feature like that, but i don't know if the clojure swank server supports it
11:58	gtrak	ah
11:58	amalloy	heh, indeed. "Wrong type argument: listp, :not-implemented"
11:59	amalloy	if it did work, though, it would be C-c C-w C-r
11:59	amalloy	for "who references"
12:00	bennylu	TimMc, yes i am bennylut
12:00	gtrak	amalloy, i can confirm "error in process filter: who-references is not implemente yet on clojure"
12:00	TimMc	bennylu: OK, so you were confused some days back about why ^foo didn't give you the metadata on foo. It turns out this was a change from CLojure 1.1. to 1.2.
12:01	TimMc	I was reading Programming Clojure and ran into the same problem.
12:01	bennylu	raek, i just checked and to clojure.core and it not throwing exception..
12:01	sattvik	gtrak: If you wanted to do it within clojure, you could probably abuse the source macro.
12:02	bennylu	TimMc, Thanks! i was reading the book programming clojure and there it was explained that that sould work, i guess that it changed after the book came of
12:02	amalloy	$source ->
12:03	sexpbot	-> is http://is.gd/yfj1XP
12:03	__name__	good morning
12:04	gtrak	anyone ever had lein marg throw an exception that it can't find the project.clj?
12:05	amalloy	TimMc: the findfn you were looking for a bit ago is probably replace
12:05	amalloy	&(replace {3 4} [1 2 3])
12:05	sexpbot	⟹ [1 2 4]
12:06	TimMc	Oh, right!
12:06	TimMc	And replace has the wrong semantics for me.
12:06	TimMc	behavior, rather
12:07	amalloy	oh?
12:08	TimMc	I need identical? instead of =.
12:10	TimMc	I ended up writing replace-1: https://gist.github.com/853113
12:10	amalloy	TimMc: you could use an identity map
12:11	TimMc	What's this now?
12:11	amalloy	http://download.oracle.com/javase/1.4.2/docs/api/java/util/IdentityHashMap.html in java - i think there's something similar in clojure
12:12	TimMc	Oh yeah, I just came across that the other day.
12:15	TimMc	Haha, it works!
12:16	TimMc	(replace (IdentityHashMap. {d0 d1}) [3 4 d0 5])
12:16	amalloy	TimMc: or (into (sorted-map-by identical?) mymap)
12:17	amalloy	except rewritten so that it actually works :P
12:25	TimMc	That's even longer.
12:25	naeu	is there anyone about that can help me understand how I may avoid inserting a race condition by using the STM and refs?
12:25	TimMc	naeu: Do you just want to make sure that a read-update-write is consistent?
12:26	naeu	TimMc: I'm not sure what you mean. In my head I want to make sure that if while I read a given ref, it can't be updated elsewhere
12:27	naeu	perhaps I just want basic locking
12:27	naeu	but that doesn't feel right
12:27	TimMc	You don't want locking. Nobody does, even if they think they do.
12:27	naeu	:-)
12:27	naeu	so I have a ref of keywords
12:28	naeu	and I want one thread to be able to look at that ref, and if a particular keyword doesn't exist in there, to register a fn to be called when it does
12:28	TimMc	A ref of a collection of keywords?
12:28	naeu	and on another thread I want to be able to update the ref and add a keyword to the collection
12:29	naeu	and call all the registered fns associated with that keyword
12:29	naeu	yup, I'm just currently using a vector
12:29	TimMc	You might find a set more appropriate than a vector, depending on your app.
12:30	naeu	TimMc: oh sure
12:30	sattvik	Does ensure solve your problem?
12:30	TimMc	But anyway, there are a couple of ways to do this, and I'm still learning about concurrency in Clojure.
12:31	TimMc	naeu: You're familiar with dosync, yes?
12:31	naeu	TimMc: by familiarity, I've used it
12:31	naeu	and I understand that it stops modification from multiple places by re-running
12:31	TimMc	So you know that inside a dosync you have a consistent view of the world.
12:31	naeu	sattvik: so you just call (ensure my-ref) in the dosync?
12:32	naeu	TimMc: sure, but is that just a consistent view of the refs you modify or also the refs you deref?
12:33	TimMc	All of them.
12:33	naeu	TimMc: perhaps not, it doesn't explain the existence of ensure
12:33	naeu	sattvik: I think that this is exactly what I need
12:34	naeu	TimMc: I believe that in a dosync the state of a ref you deref may change during the rest of the execution of the transaction
12:35	naeu	without requiring the transaction to re-run
12:35	sattvik	naeu: Your welcome.
12:35	naeu	whereas a ref you modify may not change elsewhere during the rest of the execution of the transaction
12:35	naeu	sattvik: is what I'm saying making any sense?
12:35	naeu	I might be totally wrong :-)
12:35	TimMc	huh
12:36	sattvik	From http://clojure.org/refs : No changes will have been made by any other transactions to any Refs that have been ref-set/altered/ensured by this transaction
12:37	amalloy	yes, that's what ensure is for
12:37	chouser	naeu: I don't think that's right. Once you're in a transaction, every deref of a ref will return the same value.
12:37	naeu	chouser: yeah, but it will return the first value
12:38	naeu	even if the ref has been modified elsewhere since the first deref
12:38	naeu	at least that's what I understand
12:38	chouser	oh, maybe I misunderstood you
12:38	joshua__	Alright, I'm confused. I have two programs running congomongo. If I use one of the programs to upload items via the swank repl it does fine. If I use it to upload items via normal running it fails, despite the upload being accomplished through the same method calls. The other program doesn't have this problem. What am I not understanding?
12:38	naeu	so it provides a consistent view in the transaction
12:38	naeu	but not necessarily across transactions
12:39	naeu	whereas if you change the ref, the transaction will ensure a consistent view across transactions
12:39	naeu	by forcing other transactions to repeat if necessary
12:40	naeu	which brings me to my next question - how do I have a side-effect fn get executed immediatelyafter a transaction has completed
12:41	naeu	obviously I can't put it in the transaction
12:41	naeu	do i use an agent for that?
12:41	Chousuke	dunno about immediately, but agent sends are queued until the transaction finishes
12:43	naeu	cool, i think a combo of dosync, ensure and agents will do what I want
12:43	sattvik	naeu: I may be misunderstanding your question, but can't you just call the function after the transaction? (do (dosync ...) (my-fn ...))?
12:46	sattvik	Or you can even use the result of a transaction as an argument to a function.
12:46	naeu	sattvik: I'm not sure I can as the arg to my-fn will be the dereffed ref
12:47	naeu	sattvik: that might work
12:47	amalloy	sattvik: https://github.com/Raynes/sexpbot/blob/master/src/sexpbot/registry.clj#L96 is an example of doing this
12:47	sattvik	,(conj [1 2] (dosync 3))
12:47	clojurebot	[1 2 3]
12:47	amalloy	er
12:47	amalloy	naeu: ^ was for you
12:51	mattmitchell	is there a way to extract values from a hash in a ordered way?
12:54	naeu	amalloy: so that works because bot is altered within the transaction
12:54	naeu	but if there was no alter on bot, then @bot might be different at time t+1 on another thread than the value of @bot at time t within the transaction
12:57	amalloy	naeu: https://github.com/Raynes/sexpbot/blob/master/src/sexpbot/plugins/ping.clj#L10-17 maybe? captures the return value of the dosync. still uses alter so maybe this doesn't address your concern but i guess i don't understand your concern :P
12:57	naeu	amalloy: I probably don't understand my concern either!
12:58	naeu	but i think capturing the result of a dosync will be enough
12:59	TimMc	naeu: "All reads of Refs will see a consistent snapshot of the 'Ref world' as of the starting point of the transaction (its 'read point'). The transaction will see any changes it has made. This is called the in-transaction-value."
12:59	TimMc	http://clojure.org/refs
12:59	amalloy	mattmitchell: you can use a sorted-map
13:00	amalloy	otherwise, no, hashes are not ordered
13:00	mattmitchell	amalloy: ok excellent thanks!
13:00	naeu	TimMc: so reads don't affect a transaction then?
13:00	naeu	TimMc: I don't grok this snippet " The transaction will see any changes it has made."
13:01	amalloy	&(let [x (ref 0)] (dosync (println @x) (alter x inc) (println @x)))
13:01	sexpbot	⟹ 0 1 nil
13:01	naeu	I'm assuming it means the transaction will see any changes to the ref within it, but care of changes outside of it if the ref is only read
13:01	TimMc	If I (dosync @foo (ref-set foo ...) @foo) the two reads will be different.
13:01	TimMc	amalloy: Holy shit you're fast.
13:01	naeu	TimMc: sure, but that's setting the ref from within the same transaction
13:02	naeu	TimMc: but if you did a ref-set in a different transaction on a different thread, @foo would always be the same
13:03	amalloy	naeu: that's the point. it's a transaction. you don't want to see changes others have made: if you did, it would be unrestrained global mutability, no?
13:03	naeu	exactly, but I want to retry my transaction if others have made changes to the ref I'm reading
13:03	TimMc	amalloy: Then what does ensure do?
13:03	naeu	which is why I believe I need ensure
13:03	naeu	which does exactly that
13:04	amalloy	right
13:04	amalloy	i belive you do too. we could both be wrong, but it seems like you'll find out faster if you just try
13:04	naeu	the docs say it's similar (but more efficient) to doing (ref-set myref @my-ref)
13:05	naeu	the problem is that it's not so easy to try out things that might have a race condition
13:05	raek	ensure is for when you want to ensure that a ref that you don't need to read or write from stays unmodified during the transaction
13:06	TimMc	raek: Ah! It is a way of pulling other refs into the transaction?
13:06	naeu	thanks everyone for your help, it's much appreciated
13:07	mattmitchell	amalloy: is there a way to take a hash-map, and convert it into a sorted-map?
13:07	raek	I think it's like saying "this ref must be unchanged during the transaction"
13:07	amalloy	mattmitchell: yes, but if you aren't building a sorted map to begin with it will be slow and you might as well just do (sort (keys m))
13:08	naeu	raek: that's my understanding too
13:08	devn	re-reading WhyFP is a good idea
13:08	mattmitchell	amalloy: ok makes sense. thanks.
13:08	devn	it's like re-reading the agile manifesto, it should be done every now and then
13:08	bennylu	hi, a little quiestion about managing clojure project -
13:08	devn	bennylu: go ahead
13:09	amalloy	&(let [m {"test" 1 "egr" 2 "wer`1" 3}] (print m) (print (into (sorted-map) m)))
13:09	sexpbot	⟹ {test 1, egr 2, wer`1 3}{egr 2, test 1, wer`1 3}nil
13:09	amalloy	mattmitchell: ^
13:09	bennylu	if i have a reletivly big project do you split it to several namespaces in a hirarchy similar to java?
13:10	devn	bennylu: yes and no
13:11	devn	bennylu: im trying to think of how to expand on that... heh
13:11	devn	clojure is not java so the hierarchies look a bit different
13:12	bennylu	i try - but it look like namespaces are "larger" in scope than classes and so there is too few name spaces and too much code in each ...
13:13	devn	bennylu: My opinion is that what you want to do is Separation of Concerns, and modularize where appropriate
13:13	bennylu	im finding myself scrolling reletivly large text in order to find the function that i want to modify / read
13:13	devn	ive found that it is helpful to write one gigantic file where everything lives in the same namespace
13:13	devn	and then split it out from there
13:13	devn	but i havent done anything that's like 800k lines of code
13:13	devn	so perhaps that would not work for you
13:14	devn	bennylu: clojure.core, the source, is mostly in one place
13:14	devn	over-namespacing can be equally annoying
13:15	bennylu	i not talking about 800k too :) but even on 900 lines of code it gets preety heavy to find stuff..
13:15	bennylu	yes, i know what you means .. i guess i just have to learn to use the find function more :)
13:16	amalloy	bennylu: are you using slime/swank?
13:16	devn	bennylu: i mean, this is not so much a clojure problem as it is how you decide to separate the modules
13:16	devn	"modules"
13:16	TimMc	,[(identical? 3 3) (identical? 300 300)]
13:16	clojurebot	[true false]
13:16	TimMc	Is this an instance of interning in Integer?
13:16	TimMc	or rather, in the compiler's handling of int literal?
13:16	amalloy	TimMc: yes
13:16	amalloy	the first 32 ints (or 256?) are interned
13:16	bennylu	i started with it but i hear about counterclockwise and give it a shot - its preety good ..
13:17	bennylu	so i now use cw
13:17	amalloy	bennylu: well, find ccw's "find" feature, then :P
13:17	TimMc	WHOA
13:17	amalloy	instead of looking around by hand
13:17	devn	CCW is pretty awesome if you want to stay in IDE land. learning a little bit of slime isn't a bad idea, though. it's awesome.
13:17	mattmitchell	amalloy: cool thanks again :)
13:17	bennylu	lol :)
13:17	devn	lpetit is a champ.
13:17	bennylu	lpetit?
13:17	TimMc	I just got the last screenful of text within a couple seconds. latency weirdness
13:17	devn	bennylu: he did most of CCW
13:18	amalloy	&(identical? 1 (inc 0))
13:18	sexpbot	⟹ true
13:18	devn	he put a ton of thought into the structural editing
13:18	bennylu	he did relly good job
13:18	devn	yeah it's pretty great
13:19	amalloy	funny how from where i'm sitting, your latency issues are indistinguishable from illegal drugs
13:19	devn	im an emacs guy until the day i die, but CCW is fantastic
13:19	bennylu	i tried enclojure to but it was awfull - crashing all the time and slow...
13:19	devn	amalloy: who me?
13:19	amalloy	no, tim
13:19	devn	ah
13:19	amalloy	his sudden WHOA just reminded me of stoners
13:19	devn	:)
13:19	devn	WHOA DUDE THIS FUNCTION IS LIKE, WHOA
13:20	TimMc	amalloy: Same here, actually.
13:20	TimMc	IT'S LIKE EACH SEXPR IS ITS OWN UNIVERSE
13:21	devn	hahaha
13:21	amalloy	chuckle
13:21	devn	that sounds like something id say after a beer or two
13:21	devn	im not proud of that
13:21	devn	it's just true
13:23	devn	this is your chance to make fun of me
13:24	pyr	(str :foo) yields ":foo"
13:24	amalloy	&(name :foo)
13:24	sexpbot	⟹ "foo"
13:24	amalloy	i think stoner TimMc makes an excellent observation about the ramifications of immutability
13:24	devn	amalloy: say more
13:24	pyr	amalloy: :)
13:24	pyr	amalloy: thx!
13:25	cemerick	devn: it's going to keep getting better. I'm hoping to take a day for it next week.
13:25	devn	cemerick: yeah i didn't mean to assign all of CCW's development only to lpetit
13:25	devn	thanks for your work as well. :)
13:25	cemerick	oh, wasn't trying to grab credit
13:26	cemerick	He's absolutely the driving force -- I only pitch in here and there. :-)
13:26	devn	cemerick: nono i wasn't trying to suggest you were im just interested in giving it where it's due
13:26	cemerick	:-)
13:26	devn	:)
13:26	cemerick	devn: how's things, BTW
13:27	devn	great, started a clojure meetup in Madison, WI -- have our 2nd meeting next monday, still pretty small but im slowly making the rounds to local meetup groups and attracting some interest
13:27	devn	i've slowly convinced a few ruby guys to pair program with me on some clojure
13:27	devn	they scoffed and hemmed and hawed at first, but i think i beat them into submission by showing them ruby came out of dylan, scheme, and the CLOS :)
13:30	devn	cemerick: how about you?
13:30	cemerick	devn: sorry, pulled in different directions :-)
13:31	cemerick	absurdly busy
13:31	cemerick	usually in a good way, sometimes not
13:31	cemerick	it's been an odd year so far
13:31	devn	:) sine waves or square waves?
13:31	cemerick	Been working on a bunch of Clojure open source stuff in the past couple of weeks, which is a nice change of pace
13:31	cemerick	square, definitely :-/
13:32	devn	yeah, that can be exhilirating though! when people walk in the door, hit the whiteboard and the room explodes with action that's a great feeling
13:33	devn	cemerick: going to make it to the next conj?
13:33	cemerick	devn: can't imagine not :-)
13:34	devn	:) good to hear it
13:34	devn	cemerick: what open source projects have you been cracking at? (btw if you're busy feel free to table this discussion -- i had a doctor's appointment today so I'm slacking a bit)
13:36	cemerick	devn: there's https://github.com/cemerick/bandalore, some nREPL fixes, and a refurbishing of a simpledb client library based on Rich's original implementation.
13:36	devn	cemerick: wanna give me an elevator pitch? :)
13:37	cemerick	on simpledb?
13:37	devn	nod
13:37	devn	also, i didn't know rich wrote a simpledb implementation
13:38	cemerick	devn: it's a zero-admin couchdb with "proper" indexes and ad-hoc query capabilities
13:39	cemerick	hosted by a known-good vendor, etc
13:39	cemerick	right next to the EC2 instances I'm using already, etc
13:39	cemerick	Essentially, I'm going all-in on AWS.
13:39	devn	yeah absolutely -- ive been pretty much doing everything on S3 and EC2 lately along with a bit of heroku here and there
13:39	cemerick	Thus the SQS client impl.
13:40	devn	Redis is really cool. Play with that at all?
13:40	cemerick	No, never looked at it.
13:41	cemerick	I've been trying to simplify everything as much as possible of late -- and anything with a whiff of administration overhead is getting tossed overboard.
13:41	devn	Redis in a lot of ways reminds me of the clojure STM -- do you can wrap multiple commands in a pipeline etc
13:41	cemerick	devn: FYI, the most recent maintained fork of Rich's SDB client is here: https://github.com/bapehbe/sdb
13:41	devn	O(1) for pretty much everything except on lists, and so on
13:42	cemerick	I'm mostly rebuilding it though: https://docs.google.com/document/d/1K5p2RRVtvYxBNLEJuWGNf1iZak2ri8cI73joWu9K1W0/edit?hl=en&authkey=CMDR_6AF
13:42	devn	cemerick: im definitely going to look into that
13:42	devn	we've been using mongo quite a bit lately
13:42	devn	(where appropriate of course)
13:42	cemerick	it sounds like redis has a lot going for it, especially since they managed to work out larger-than-memory datasets
13:43	cemerick	That was the limitation that kept me away initially
13:43	devn	cemerick: the coolest part of redis that i have yet to toy with is the pub/sub system
13:43	devn	http://redis.io/commands#pubsub
13:46	devn	it gives you what is essentially a broadcast server to transmit messages over channels to many subscribers in real time
13:47	devn	lots of cool ideas come to mind
13:50	edw```	Are there Clojure-native string->number procedures? I wind up doing #(Integer. %) a lot, which is rather tedious.
13:50	cemerick	edw```: if you're certain the string only contains a number literal, use read-string
13:50	edw	That sort of seems like using an atomic bomb when a firecracker is called for. How efficient is that?
13:50	edw	In practive, I have STRING-TO-INT and STRING-TO-FLOAT defined in a million files, which is what makes me think having a built-in would be wise. (I do a lot of reading from text files and URLs.)
13:54	cemerick	ah, so an ad-hoc mq
14:07	devn	cemerick: yeah good way of thinking about it
14:07	devn	cemerick: i think about using it for things like...you have data being funneled from one big EC2 instance to many smaller instances that handle specific subsets of the total dataset
14:08	devn	this is probably a cliche by now, but also, if you wanted to do a Twitter clone, that's your ticket
14:09	devn	redis 2.3 is i believe going to introduce a more complete distributed system, it will be interesting to see how pub/sub works in that context
14:09	Nanarpuss	Anyone work with slime? I'm getting an error everytime I hit return on the REPL... It says "Error in process filter: Wrong number of arguments: nil, 1"
14:10	devn	Nanarpuss: ah yeah i was getting that... i think it's your version of SLIME
14:10	devn	are you running slime from source?
14:10	Nanarpuss	yeah
14:10	devn	yeah, use the ELPA package
14:10	mattmitchell	i'm using the contrib.sql lib and attempting to insert a date to mysql. How does it handle dates? Just as strings? Do I have to format the value myself?
14:10	Nanarpuss	I've tried ELPA too
14:10	devn	that will get rid of it
14:10	devn	Nanarpuss: hm, weird. that fixed it for me
14:11	Nanarpuss	so ELPA slime and swank-clojure worked for you?
14:11	devn	Nanarpuss: are you sure you don't have slime loading from source still?
14:11	devn	Nanarpuss: yes. with 1.3.0-SNAPSHOT
14:11	Nanarpuss	ohh I'm on 1.2
14:11	Nanarpuss	let me try 1.3 and see what happens
14:11	devn	Nanarpuss: im not sure how much of a difference it makes, but that's my setup and it seems to be working
14:12	raek	I don't think the clojure version should make any difference here
14:12	devn	raek: is 1.3.0-SNAPSHOT just for clojure 1.2 then? and swank-clojure is just 1.2?
14:12	devn	err and swank-clojure 1.2 is just for 1.1.0?
14:13	technomancy	any version of swank-clojure should work with all clojure versions
14:13	raek	ah, thought you were refering to clojure versions...
14:13	technomancy	modulo a few times where I apply patches I get without thinking them through =(
14:13	devn	technomancy: i saw your post on the Wrong number of arguments: nil, 1 i think
14:13	devn	IIRC you suggested to just use the ELPA packages, and so I did, and then never received the error again
14:13	technomancy	the slime version is what you have to watch out for
14:14	devn	i was compiling from source
14:14	devn	technomancy: why no marmalade in the starter-kit, btw?
14:14	technomancy	I wish that were simpler, but I don't really have the patience to work it out with the CL guys.
14:14	technomancy	devn: no reason; just haven't gotten around to it
14:15	technomancy	tarball packages are slightly more complicated; I guess that's the excuse
14:15	devn	nod -- ill submit a pull req.
14:16	TimMc	What is a use-case of ensure?
14:17	TimMc	That is, why protect a ref from modification if you never read or write it in that transaction?
14:19	devn	TimMc: ive seen several opinions on that
14:20	devn	what ive concluded is that it's a read with an annotation
14:20	devn	it increases parallelism w/r/t a dummy read/write like ref-set
14:20	TimMc	Surely there's no behavioral difference within one transaction between @foo and (ensure foo)?
14:21	devn	i think it basically means that you're going to be changing foo later and so others should stay away from it
14:21	devn	maybe to ease contention?
14:21	Nanarpuss	hmm still no luck
14:21	Nanarpuss	just tried 1.3
14:22	TimMc	devn: Like a way to say early on in a long transaction, "back off, I'll be using this"?
14:22	devn	TimMc: i THINK so
14:22	devn	it increases isolation
14:22	bennylu	what is the difference between into and concat?? (besides the order of the result)
14:23	TimMc	I don't see any usage inside the clojure source.
14:23	amalloy	bennylu: concat is lazy
14:23	bennylu	amalloy, thanks!
14:23	amalloy	&(take 1 (into () (range)))
14:23	devn	TimMc: i think it is ref-set's half-brother
14:23	amalloy	&(take 1 (concat () (range)))
14:23	sexpbot	⟹ (0)
14:23	raek	bennylu: into is conj'ing on some element to any data structure, concat concatenates two sequences
14:23	sexpbot	Execution Timed Out!
14:24	TimMc	bennylu: I believe into gives you back a collection of the type you asked for.
14:24	devn	TimMc: i think i found an answer for you
14:24	amalloy	TimMc: into is just (partial reduce conj), more or less
14:25	amalloy	&((partial reduce conj) [1 2] (range 5))
14:25	sexpbot	⟹ [1 2 0 1 2 3 4]
14:25	amalloy	&(into [1 2] (range 5))
14:25	sexpbot	⟹ [1 2 0 1 2 3 4]
14:25	raek	,[(into [1 2] [3 4]) (into (list 1 2) [3 4]) (concat [1 2] [3 4]) (concat (list 1 2) [3 4]]
14:25	clojurebot	Unmatched delimiter: ]
14:25	raek	,[(into [1 2] [3 4]) (into (list 1 2) [3 4]) (concat [1 2] [3 4]) (concat (list 1 2) [3 4])]
14:25	clojurebot	[[1 2 3 4] (4 3 1 2) (1 2 3 4) (1 2 3 4)]
14:25	devn	TimMc: The scenario you describe cannot happen in Clojure's STM. Clojure's STM uses MVCC and provides snapshot isolation to transactions - a transaction will never see inconsistent state. Being MVCC-based, it is subject to write skew, and provides an ensure construct that allows one to tag dependent reads, with more concurrency than the dummy writes usually used to address write skew. Livelock is a theoretical scenario, but it is not a non-blocking ...
14:25	devn	... design, thus mitigating churn. Actual livelock is avoided via retry limits and timeouts. There is, as you mention, as-yet-unrealized potential for configurable contention resolution policy.
14:26	devn	-rich hickey, 2009
14:27	TimMc	I don't know what livelock is (though I could guess) and I don't know what write skew is.
14:27	TimMc	So... ensure is probably there if you need super concurrency performance.
14:27	TimMc	...but is never strictly necessary from a results point of view.
14:27	devn	TimMc: there's a lot of literature out there, but most of it is specific to an implementation
14:29	devn	TimMc: i wish i could be of more help, but i can't really give you anything more than i already have without speculation
14:29	TimMc	As long as I don't need to know about ensure, I'll probably hold off on trying to figure it out. :-)
14:30	devn	TimMc: yeah I'm hunting for some code that uses it, but then you need to be sure that they're not just using it for the sake of using it
14:30	TimMc	It's not present in contrib either, I think.
14:31	devn	TimMc: http://www.cs.rochester.edu/research/synchronization/rstm/primer.shtml
14:31	devn	that's interesting and somewhat relevant to this discussion
14:31	TimMc	(I've only beenlooking on the .clj side of things.)
14:31	devn	TimMc: http://www.cs.rochester.edu/research/synchronization/rstm/libraries.shtml
14:31	devn	that's good as well
14:33	gfrlog	,(format #"this won't work %s cuz it's a regex" "oh well")
14:33	clojurebot	java.lang.ClassCastException: java.util.regex.Pattern cannot be cast to java.lang.String
14:33	gfrlog	so is there any function for regexly escaping a string?
14:33	gfrlog	and did I state that question in an understandable way?
14:33	devn	IIRC there is
14:34	gfrlog	I just looked on java.util.regex.Pattern and don't see anything
14:34	TimMc	$findfn "." "\\."
14:34	sexpbot	[]
14:34	gfrlog	TimMc: brilliant, if unsucessful
14:35	devn	i used to have a thingamajig that let me build up a regex from strings
14:35	brehaut	(str #".")
14:35	brehaut	,(str #".")
14:35	gfrlog	,(str #".")
14:35	clojurebot	"."
14:35	clojurebot	"."
14:35	TimMc	ooh
14:35	TimMc	,(java.util.regex.Pattern/quote ".")
14:35	clojurebot	"\\Q.\\E"
14:35	gfrlog	wtf is \Q and \E?
14:35	TimMc	Oh, uh, I guess that works too.
14:36	jweiss	quote, end quote?
14:36	gfrlog	man I looked right at that function in the javadocs and didn't see it cause it wasn't called "escape"
14:36	TimMc	,"\\"
14:36	clojurebot	"\\"
14:36	gfrlog	,(java.util.regex.Pattern/quote "\\E")
14:36	clojurebot	"\\Q\\E\\\\E\\Q\\E"
14:36	gfrlog	holy cow
14:37	TimMc	haha
14:37	gfrlog	man testing to make sure that does what I think it does sounds like a headache
14:37	TimMc	,(java.util.regex.Pattern/quote "\\$")
14:37	clojurebot	"\\Q\\$\\E"
14:37	devn	this seems like the wrong way to go about doing this...
14:38	gfrlog	devn: it sounds perfect, what could be wrong with it?
14:38	TimMc	,(java.util.regex.Pattern/quote "$")
14:38	clojurebot	"\\Q$\\E"
14:38	gfrlog	,(re-pattern (java.util.regex.Pattern/quote "\\E"))
14:38	clojurebot	#"\Q\E\\E\Q\E"
14:38	devn	maybe i misunderstand your original problem, but you wanted to call format on a regex
14:38	devn	i dont see how this solves your problem
14:38	TimMc	OK, so it doesn't attempt to quote its own sentinals via nesting or anything.
14:38	gfrlog	devn: no, I actually just needed an escape
14:38	gfrlog	,(re-pattern (java.util.regex.Pattern/quote "\\E\\Q\\E"))
14:39	clojurebot	#"\Q\E\\E\Q\Q\E\\E\Q\E"
14:39	gfrlog	how the heck does that work?
14:39	devn	lol
14:39	gfrlog	devn: I can do format manually with (str)
14:39	gfrlog	devn: then pass to re-pattern
14:39	devn	okay now we're on the same page gfrlog
14:39	gfrlog	I'm seriously dumbfounded by the escaping strategy here
14:40	devn	that's what my suggests was
14:40	devn	suggestion*
14:40	gfrlog	I'm sure it works but I'm not sure why
14:40	TimMc	After a \Q, go into raw mode until \E.
14:41	TimMc	,(java.util.regex.Pattern/quote "\\")
14:41	clojurebot	"\\Q\\\\E"
14:41	Null-A	,```foo
14:41	clojurebot	(clojure.core/seq (clojure.core/concat (clojure.core/list (quote quote)) (clojure.core/list (quote sandbox/foo))))
14:41	TimMc	See, that string is \Q\\E, but the \\ isn't an escape.
14:42	TimMc	For a literal \E, drop out of raw mode, emit an escaped \E (\\E) and then go back into raw mode.
14:42	TimMc	It's a bit silly that it puts empty raw clauses in when the beginning or end of a string is \E
14:43	devn	"patches welcome" ;)
14:43	gfrlog	TimMc: okay, I think that makes sense
14:43	gfrlog	thanks
14:43	smnirven	got a question about clojure.contrib.sql with-query-results
14:43	gfrlog	smnirven: ask that question
14:44	smnirven	im trying to write a query by datetime, so I'm building a prepared statement - its not clear what I have to pass in
14:44	smnirven	here's my code:
14:44	smnirven	(sql/with-connection db/conn
14:44	smnirven	(sql/with-query-results rs [(str "select * FROM users WHERE updated_at >= ?" [start-dt-str])]
14:44	smnirven	(doseq [res rs]
14:44	smnirven	(prn res)))))
14:45	gfrlog	you're right. that is not clear. Have you tried anything?
14:45	smnirven	yeah, tried running that code - got this error
14:45	gfrlog	I know with sql you can use some kind of time literal in single-quotes. Maybe c.c.sql will take a string?
14:45	smnirven	java.sql.SQLException: No value specified for parameter 1 (NO_SOURCE_FILE:0)
14:46	gfrlog	smnirven: I don't think you want the argument to be in a vector
14:46	gfrlog	i.e., use start-dt-str instead of [start-dt
14:46	smnirven	yeah, in that code, start-dt-str is a string
14:46	gfrlog	-str]
14:46	smnirven	just get rid of the vector
14:46	gfrlog	right
14:46	smnirven	cool, i'll try that quick
14:46	TimMc	smnirven: Is start-dt supposed to be inside (str ...)?
14:46	gfrlog	the error message still looks weird, but maybe that's why anydow
14:46	gfrlog	anyhow*
14:47	smnirven	nope, it gets passed into a function as a string
14:47	TimMc	smnirven: ##(str "f" 5)
14:47	sexpbot	⟹ "f5"
14:47	TimMc	Do you want concatenation?
14:47	gfrlog	maybe you forgot to include the (:fix-bugs) clause within the namespace declaration
14:47	gfrlog	TimMc: I think he was just using the c.c.sql api wrong
14:48	smnirven	here's a more direct example:
14:48	smnirven	(sql/with-query-results rs [(str "select * FROM raw_leads WHERE sdb_updated_at >= ?" "2011-03-03 12:00:00")]
14:49	TimMc	smnirven: Right, you don't want the date inside str.
14:49	smnirven	ohh i think i see what i did
14:49	smnirven	yeah
14:49	smnirven	oy - thanks
14:49	TimMc	Just kill str, actually.
14:49	TimMc	np
14:50	smnirven	excellent
14:50	smnirven	that worked
14:50	smnirven	ty
14:51	gfrlog	oh weird I didn't even see he did that in the original code
15:49	chouser	is this old news here? http://doc.akka.io/stm-java
15:49	mattmitchell	i have a lazy seq. i'd like to use map, to transform all of the values. i seriously, can't figure out how to do this, but i'm thinking doall might help me out here?
15:50	chouser	mattmitchell: why do you want to force the lazy seq instead of letting it remain lazy?
15:51	mattmitchell	hmm, let me try something
15:51	mattmitchell	chouser: is it possible to use map on a lazy seq?
15:52	chouser	mattmitchell: absolutely. and map returns a lazy seq in turn.
15:52	mattmitchell	chouser: interesting. ok.
15:55	TimMc	Wait wait wait... http://lambda-the-ultimate.org/node/3700#comment-52647 indicates that transactions do not provide consistency, if I'm understanding write skew correctly.
15:59	chouser	within the transaction, you always see a consistent state.
16:00	TimMc	That's isolation, I think.
16:00	chouser	As I understand it, most relational databases that claim ACID are also subject to write skew unless you do dummy writes.
16:01	TimMc	...which is what ensure is a replacement for.
16:01	chouser	right
16:02	chouser	in practice, it's an unusual bit of code that is susceptible to write skew, but of course it's worth knowing about so that you can use ensure when needed.
16:02	amalloy	mattmitchell: ##(take 10 (map inc (range)))
16:02	sexpbot	⟹ (1 2 3 4 5 6 7 8 9 10)
16:02	TimMc	chouser: How do I know if I need it?
16:03	TimMc	Rather, do you know of an example of Clojure code that is susceptible?
16:12	TimMc	OK, so it looks like I need to ensure any refs whose state I only read but whose final value must be consistent with refs I am writing.
16:12	chouser	that's a better description than I was in the middle of writing. :-)
16:14	TimMc	OK, I'll put this on the clojuredocs site.
16:16	TimMc	Look good? http://clojuredocs.org/clojure_core/clojure.core/ensure
16:17	TimMc	devn: ^ found out about ensure
16:18	TimMc	And now if you'll excuse me, I'm off to make sure all my dosyncs are safe from write skew.
16:29	TimMc	Here's a question: If inside a writing dosync I call a bunch of methods that read from various global refs, how am I supposed to know what I might need to ensure?
16:31	TimMc	amalloy: How does that help?
16:32	amalloy	TimMc: it doesn't really
16:32	TimMc	heh
16:32	chouser	TimMc: you really want to keep your transactions as small and contained as possible
16:32	amalloy	but i find it easier to think about having a single mutable object enclosing the N things i might need to change
16:33	amalloy	if i had lots and lots of threads hammering on it at once that might be bad for performance, but this way i don't have to worry about other reds
16:33	amalloy	refs
16:35	mattmitchell	trying to get contrib.sql do-prepared to work with a collection of records. Anyone know if this actually works with a collection?
16:36	TimMc	My app is a Swing graphics program where everything runs off the event loop, so it is essentially a single-threaded program. I don't really need to worry about concurrency. But the moment I add another thread, it'll matter.
16:38	TimMc	chouser: When the user drags something on the canvas, I have to use a snapshot of the current view rotation, translation, and scale along with the program's tool mode and the list of objects on the canvas. I do some computation, and then I need to update the objects on the canvas and maybe the tool state.
16:39	TimMc	I do try to keep the transactions small and contained, but in this case one atomic unit of work involves about 3 different refs of maps, minimum.
16:40	amalloy	TimMc: wtf, no it doesn't. minimum, it involves one atom enclusing three maps :P
16:41	TimMc	amalloy: If I merge all my global state into one reference, my program can no longer make use of concurrency when I add threads for animation, etc.
16:43	amalloy	animation threads can just get a @snapshot and not worry if it's a little out of date, no?
16:43	amalloy	i mean, i'm not asserting that your app would be better with atoms
16:43	amalloy	but to claim that it is impossible with atoms is patently false
16:46	TimMc	I suppose that animation just needs a snapshot, yeah. It wouldn't be writing anything back to references.
16:46	TimMc	amalloy: Only one transaction could run on the atom at a time, right?
16:47	amalloy	yes
16:47	amalloy	or at any rate only one could succeed
16:47	TimMc	right
16:48	TimMc	I guess I'll stop complaining until I actually need concurrency. :-P
17:10	solar_sea	When I try to start "lein repl" in a new project, I'm getting this - http://pastebin.com/sxJdqYNk What host / port does lein's repl command require ?
17:11	solar_sea	http://pastebin.com/9zmSKe4R - nothing weird in netstat either
17:12	dmiles_afk	does clojure's "," syntax preclude it from ever being read by the lispreader?
17:13	technomancy	solar_sea: it uses localhost and a random port above 1024, but you can override it with LEIN_REPL_HOST LEIN_REPL_PORT
17:13	technomancy	solar_sea: is it repeatable?
17:13	solar_sea	yes, everytime
17:14	dmiles_afk	i suppose a reader macro of #J could make the lisp reader tollerate clojure's ","
17:14	dmiles_afk	"," is alwaswy whitespace right?
17:15	hiredman	yes
17:15	technomancy	solar_sea: can you open a ticket with copious details so I can check it later?
17:15	solar_sea	sure, where's the tracker for it ?
17:15	dmiles_afk	teh [ and ] might i guess get tricky
17:16	technomancy	solar_sea: http://github.com/technomancy/leiningen/issues
17:16	TimMc	dmiles_afk: And {}
17:20	NielsE	hi, I have created a new clojure project in eclipse but it does not recognise things from contrib like 'sqrt' and 'primes', but clojure-contrib is in the classpath under libraries in eclipse, how come?
17:21	TimMc	chouser: I would really like to see some mention of write skew on the clojure.org/refs page. Should I bug Rich about that?
17:22	TimMc	NielsE: Have you used :require or :use in your namespace declaration to pull in contrib?
17:23	NielsE	TimMc: somehow I was not aware that I had to use or include the contrib library explicitely, I'll look into it, thanks :)
17:24	raek	technomancy: what does it mean for a project to be installed in leiningen? (I'm thinking about two-param "lein install")
17:24	technomancy	raek: it places shell scripts in ~/.lein/bin
17:24	raek	also, I just discovered "lein repl" outside a project and the swank-clojure shell wrapper. this will aid my introductory talk on clojure very much. :)
17:24	technomancy	raek: I think swank is the only thing that uses it so far
17:25	technomancy	but I want more people to try it out; clojure's command-line story right now sucks =\
17:25	technomancy	cools!
17:27	solar_sea	technomancy, I found it, it turned out that my "lo" iface somehow was down
17:27	TimMc	NielsE: (:require [clojure.contrib.math :as math]) in your (ns ...) will let you do math/sqrt
17:27	solar_sea	there's nothing wrong with lein :)
17:27	technomancy	solar_sea: whoa; I didn't even know you could do that. =)
17:28	solar_sea	me neither ... I guess the wicd network manager that I use for wifi settings is to blame, I'll dig it up further some day :)
17:28	TimMc	solar_sea: How did you discover that?
17:29	solar_sea	netstat showed nothing wrong. LEIN_REPL_PORT/HOST didn't work either. Then I disabled ipv6, again to no avail. And I glanced again that "lo" was actually missing from ifconfig's output.
17:30	TimMc	Entirely missing? I would not have noticed that ever.
17:46	TimMc	Is the rational for class-per-fn that this allows selective code reloading?
17:54	mattmitchell	if i have a function, that accepts a series of optional arguments, how can i pass in a list of args without knowing the length?
17:55	brehaut	(apply + [1 2 3 4 5])
17:55	brehaut	,(apply + [1 2 3 4 5])
17:55	clojurebot	15
17:55	mattmitchell	brehaut: ok cool. so the function i'm actually working with is clojure.contrib.sql do-prepared
17:55	mattmitchell	brehaut: i have a collection of row values
17:56	mattmitchell	looks something like this: (sql/with-connection db/conn
17:56	mattmitchell	(sql/do-prepared insert values))
17:56	brehaut	(apply clojure.contrib.sql/do-prepared foo bar seq-of-values)
17:56	mattmitchell	brehaut: ahh ok :)
18:01	mattmitchell	brehaut: thank you
18:02	brehaut	no worries
18:02	raek	TimMc: what would be the alternative to class-pre-fn? you need to have separate classes for separate functions if one function should behave differently from another when called with the same method
18:05	TimMc	Oh right, there are different methods for different arities.
18:06	amalloy	TimMc: i don't think that's relevant
18:06	amalloy	the point is that functions have to have a general "call me" button, which has to be wrapped up in a method for java
18:06	amalloy	if function a is to behave differently from function b, they must be different classes implementing IFn
18:06	TimMc	And they all have to be instances of different classes, right.
18:45	amalloy	TimMc: plus, have you ever thought about how closures are implemented? it's a neat trick
18:45	TimMc	Hmm, fair point/
19:10	bennylu	what the equivalance of substring in clojure?
19:11	bennylu	anyone?
19:12	clojurebot	Please do not ask if anyone uses, knows, is good with, can help you with <some program or library>. Instead, ask your real question and someone will answer if they can help.
19:12	Apage43	,(.susbtring "doghouse" 3)
19:12	clojurebot	java.lang.IllegalArgumentException: No matching method found: susbtring for class java.lang.String
19:12	bennylu	getit! thanks..
19:12	Apage43	yeah, that should work outside the bot xD
19:14	amalloy	subs
19:14	amalloy	which i think is in clojure.string
19:14	amalloy	&(use 'clojure.string)
19:14	sexpbot	⟹ nil
19:14	amalloy	&(subs "test" 1)
19:14	sexpbot	java.lang.IllegalStateException: replace already refers to: #'clojure.string/replace in namespace: sandbox6385
19:15	amalloy	&(use 'clojure.string)
19:15	sexpbot	java.lang.IllegalStateException: replace already refers to: #'clojure.string/replace in namespace: sandbox6385
19:15	amalloy	lol wtf
19:15	amalloy	oh i guess it's in core anyway
19:15	amalloy	&(subs "test" 1)
19:15	sexpbot	⟹ "est"
19:15	amalloy	bennylu: ^
19:16	bennylu	amalloy, Thanks!
19:34	bennylu	what the convention for constants in clojure? (for example - in jave its uppercase splitted by '_')
19:35	technomancy	bennylu: lowercase dash-separated
19:37	bennylu	technomancy, but this is the convention for normal variables - because clojure dont have a final/constant keyword i wanted to show the readers of my code that some variable is constant - i guess i will have to add somthing like c-varname
19:38	Apage43	bennylu: shouldn't the preponderance of your variables in clojure be constant..
19:39	Apage43	if you
19:39	technomancy	you can tell when things are mutable by the presence of deref/atom/agent/ref
19:39	Apage43	if you're going around re'def'ing things that's probably wrong
19:40	bennylu	Apage43, i guess you right.. :)
19:40	bennylu	i still thinking in java :)
19:43	pdk	bennylu it's a given that they're constant
19:43	amalloy	how do i specify a "source dependency" with cake/lein? it looks like with maven you add a <classifier> element
19:43	pdk	they're all immutable :p
19:43	pdk	if you're naming a global symbol though
19:43	pdk	the convetion is like-this
19:43	amalloy	pdk: that's overgeneralizing
19:44	amalloy	you define global symbols all the time; only the ones that you intend to be rebound are usually given earmuffs
19:44	pdk	barring java objs/reference types
19:44	amalloy	ooo i see there's a :classifier entry in the dependency thingy
19:44	bennylu	pdk, amalloy, thanks
19:50	TimMc	amalloy: I was using the convention of all my global refs (there are about 5) have, uh, earmuffs.
19:50	amalloy	well, altering global refs is similar to rebinding
19:51	amalloy	except more evil :P
20:00	technomancy	amalloy: what are you using source dependencies for?
20:00	amalloy	technomancy: i'm not really. i just wanted an easy way to get the source for a project
20:01	technomancy	I could see the use for a plugin that could pull in source and build a TAGS file if I had the misfortune to need such a thing.
20:02	technomancy	seems saner to inspect the <scm> element of the pom though
20:16	pdk	hm
20:16	pdk	i'll ask again, for folks who preordered joy of clojure through amazon do you know if you still get early access that way
20:58	TimMc	What is the M in MEAP?
20:58	TimMc	(speaking of EAP)
21:00	brehaut	Manning (the publisher)
21:00	brehaut	(i think)
21:02	TimMc	Hah, OK.
21:24	amalloy	indeed
21:30	devn	so erm, any idea on a good regex to capture sexps from strings?
21:32	brehaut	devn, do you want to just find them? or actually get sexps back?
21:32	devn	im typing in this line right now and then i do this (foo (bar (baz 4) "16") \c)
21:33	devn	i want to capture (foo (bar (baz 4) "16") \c)
21:33	Despite_	ooo, fun!
21:33	brehaut	devn: theres not really a good solution to that with regexp
21:33	devn	i figure this is a solved problem but, hm...
21:33	amalloy	devn: if you use regexes to do this you are asking for pain, and also are probably a satan worshipper, no offense
21:33	Despite_	you'll need perl for this!
21:33	devn	amalloy: well, how do you suggest i do it?
21:33	brehaut	for instance (is this) one or (two sexp) ?
21:34	amalloy	&(read-string "(foo (bar (baz 4) \"16\") \c)")
21:34	sexpbot	java.lang.Exception: Unsupported escape character: \c
21:34	brehaut	fnparse
21:34	amalloy	&(read-string "(foo (bar (baz 4) \"16\") \\c)")
21:34	sexpbot	⟹ (foo (bar (baz 4) "16") \c)
21:34	devn	https://gist.github.com/854070
21:34	devn	that works right now, and it's fast
21:34	devn	but im sick of that code. it's disgusting.
21:35	Despite_	wow
21:35	brehaut	devn: you really are outside of the bounds of regular grammars, and need to write areal parser
21:35	amalloy	devn: please comment on why read-string is no good?
21:36	devn	&(read-string "hello i am in the #clojure irc channel (foo (bar (baz 4) \"16\") \c)")
21:36	sexpbot	java.lang.Exception: Unsupported escape character: \c
21:36	devn	&(read-string "hello i am in the #clojure irc channel (foo (bar (baz 4) \"16\") \\c)")
21:36	sexpbot	⟹ hello
21:36	amalloy	&(with-in-string "hello i am in the #clojure irc channel (foo (bar (baz 4) \"16\") \\c)" (take-while identity (repeatedly read)))
21:36	sexpbot	java.lang.Exception: Unable to resolve symbol: with-in-string in this context
21:37	amalloy	&(with-in-str "hello i am in the #clojure irc channel (foo (bar (baz 4) \"16\") \\c)" (take-while identity (repeatedly read)))
21:37	sexpbot	Execution Timed Out!
21:37	amalloy	well, something like that anyway
21:37	amalloy	you probably need a try/catch for eof
21:38	devn	it doesn't need to be perfect and like...understand that \c is ok. it basically just needs to match an equal number of parens on both sides
21:38	devn	(((()))) is valid, for instance
21:39	amalloy	devn: the "regular" in regular expressions means that it has to be context-free, ie not tracking nested parens
21:39	devn	(1(j(4(d)))), same deal
21:39	brehaut	devn are you familiar with http://en.wikipedia.org/wiki/Pumping_lemma_for_regular_languages ?
21:40	devn	brehaut: no, reading now
21:40	devn	amalloy: nod, fair enough
21:40	amalloy	these days regular expressions have some non-regular extensions that do allow you to do stuff like this, but there are so many reasons not to, especially when you have a whole dang compiler at your disposal
21:40	TimMc	devn: TL;DR: You at least need a stack.
21:40	amalloy	heh
21:40	devn	lol
21:40	devn	pumping lemma sounds like a math porn movie
21:41	TimMc	hawt
21:41	amalloy	TimMc: how much will it cost me to have you follow me around with tldr explanations of my verbose rubbish?
21:41	TimMc	:-P
21:43	devn	lol
21:44	Despite_	perl -MText::Balanced :)
21:44	brehaut	devn the 'best' you can use regexps for here is tokenisation such as ##(re-seq #"(\"(\\.\|[^\"])\")\|[()]\|[^()\"]" "abc ( 1 2 ( c d \"ber\" ) ) ) asdf")
21:44	sexpbot	⟹ (["abc " nil nil] ["(" nil nil] [" 1 2 " nil nil] ["(" nil nil] [" c d " nil nil] ["\"ber\"" "\"ber\"" "r"] [" " nil nil] [")" nil nil] [" " nil nil] [")" nil nil] [" " nil nil] [")" nil nil] [" asdf" nil nil] ["" nil nil])
21:44	brehaut	please excuse the evil
21:44	devn	holy evil
21:44	devn	that's almost worst than what i have now :D
21:44	brehaut	haha
21:44	devn	(but i appreciate the suggestion (and yes this should match too))
21:44	brehaut	its also bound to be broken
21:45	devn	i mean, here's the scenario so you have some context
21:45	devn	because maybe this changes things...
21:46	devn	im rewriting something i was messing with around a year ago that read-lines from the #clojure logs, pulls out s-exps and try to run them in a sandbox
21:46	devn	if they run, the expression as a string is the key, and their value is the result as a string
21:46	devn	that happens in a try catch so i dont really care if its faulty, liberal with parens, etc.
21:47	devn	i just want something that is good enough
21:49	amalloy	&1
21:49	sexpbot	⟹ 1
21:49	brehaut	$findfn [1 2 3] ([1 2 3] [2 3] [3] [])
21:49	sexpbot	java.security.PrivilegedActionException: java.lang.IllegalArgumentException: Wrong number of args (3) passed to: PersistentVector (NO_SOURCE_FILE:0)
21:50	amalloy	devn: that's a sexp you won't get right :P
21:55	brehaut	devn: (defn tails [s] (when (seq s) (lazy-seq (cons s (tails (rest s)))))) (defn horror [s] (keep #(try (read-string (str %)) (catch Exception e e)) (tails s)))
21:56	brehaut	its missing an apply before str
21:57	brehaut	(defn horror [s] (keep #(try (read-string (apply str %)) (catch Exception e nil)) (tails s)))
21:57	brehaut	much better (for a given value of better)
21:57	brehaut	that'll find all the legit clojure expressions in a string
21:57	brehaut	including a bunch of stuff you dont want (eg, anything that looks like a symbol)
21:58	amalloy	brehaut: given input " 1" you'll generate a zillion instances of the expression "1"
21:58	brehaut	amalloy: he said it had to be approximate ;)
21:58	amalloy	also isn't tails just (partial reductions rest)?
21:59	amalloy	er not quite
21:59	brehaut	i know theres a good way to do it
21:59	brehaut	but its late friday here and my brain is tired
21:59	amalloy	brehaut: late friday already?
21:59	amalloy	it's barely late thursday here
21:59	brehaut	new zealand, its the future
21:59	brehaut	by late i mean late in te work day; about 4pm
22:00	amalloy	i guess i was reading late as 11pm
22:00	brehaut	(defn horror [s] (set (keep #(try (read-string (apply str %)) (catch Exception e nil)) (tails s))))
22:00	brehaut	hows that :P
22:00	amalloy	(defn tails [s] (take-while identity (iterate #(subs % 1) s)))
22:00	amalloy	brehaut: my hero!
22:01	brehaut	hah brilliant :)
22:01	amalloy	i use take-while/identity/iterate so often i need to give it a function
22:01	amalloy	name proposals?
22:01	chouser	TimMc: point 8 refers to the usage of ensure. You wish it used the words "write skew" in particular?
22:03	brehaut	amalloy: its a "take-" something for sure
22:03	brehaut	perhaps even just take-iterations ?
22:03	amalloy	i have trim-seq for take-while identity
22:03	amalloy	hm, sensible
22:03	amalloy	or just iterations
22:04	brehaut	yeah that could work
22:05	amalloy	brehaut: putting that into my new little portably utils library now
22:06	brehaut	awesome :)
22:07	brehaut	amalloy: i see you have on-thread; why not join the lazier world and just use future :P
22:08	amalloy	well yes
22:08	amalloy	brehaut: i have that there because i grabbed everything from sexpbot.utils, and apparently Raynes has a reason to want different error semantics
22:08	amalloy	mebbe i'll junk it
22:11	brehaut	also, (def make-str (transform-if keyword? name str)) instead of keyword you probably want (partial instance? clojure.lang.Named)
22:12	amalloy	brehaut: good point. that too was extracted from another application
22:12	amalloy	as you can see my util package is pretty new so it's rough around the edges
22:12	brehaut	yeah for sure
22:12	brehaut	no point creating a utilities package whole cloth
22:12	amalloy	heh
22:13	amalloy	i'll wait until i can use it to replace contrib, then release it
22:13	brehaut	haha
22:20	brehaut	later
22:46	dnolen	does calling seq on a lazy-seq force evaluation of the first item?
22:46	dnolen	to determine if it's non-empty?
22:48	dnolen	ah
22:48	dnolen	it seems like it does.
22:49	amalloy	dnolen: yes
22:50	amalloy	next is basically (comp seq rest)
22:50	amalloy	er, no it's not. but whatever
23:26	amac	the docstring for future-cancel is hilarious
23:28	tomoj	I never read it that way before :)
23:29	amac	:)
23:31	spewn_	,(doc future-cancel)
23:31	clojurebot	"([f]); Cancels the future, if possible."
23:31	spewn_	hah
23:34	amalloy	heh
23:34	amalloy	hopefully it always fails
23:35	amalloy	arguably it doesn't matter though. some kind of variation on the quantum bogosort
23:39	amalloy	man, the wikipedia article on quantum bogosort is terrible. if anyone is wondering why i would make such a stupid reference, see http://www.mathnews.uwaterloo.ca/Issues/mn11103/QuantumBogoSort.php
23:45	amac	Man, I hope some parallel asshole doesn't destroy our universe simply because his list was unsorted.
23:46	amac	I like this universe, it contains all my stuff.
23:47	dnolen	is it possible to get the name of a fn like (fn foo []) ?
23:48	technomancy	dnolen: there's an open ticket for putting stuff like that in metadata
23:48	technomancy	(no patch, just an unhelpful "this should have metadata")
23:48	dnolen	technomancy: heh, thx.
23:49	amalloy	dnolen: you can kinda-sorta do it with ##(class (fn foo[]))
23:49	sexpbot	⟹ sandbox11264$eval13423$foo__13424
23:49	dnolen	,(println (fn foo[]))
23:49	clojurebot	#<sandbox$eval2577$foo__2578 sandbox$eval2577$foo__2578@1a707a0>
23:50	dnolen	I just need it for debugging really. would prefer to not get the mangled version.
23:50	amalloy	dnolen: regexes for the win?