#clojure – 2011-04-29

2011-04-29

00:00	dnolen	choffstein: what I mean is what advantage over an atom?
00:00	choffstein	...uh, no idea. As I said, I am very new to clojure :)
00:01	amalloy	i wonder if the popularity of refs, when atoms would do, is related to refs being an older language feature
00:01	amalloy	(they are, right? i'm not imagining it?)
00:01	dnolen	choffstein: dosync is about coordinating changes between data, if you just need to serialize access to something, atoms are fine and much faster.
00:01	choffstein	amalloy: I use ref because I come from a SML background -- and ML has refs. Maybe that's it?
00:02	choffstein	dnolen: ah, I see. atoms may be okay then :)
00:02	cemerick	amalloy: "I'm using _STM_, baby!" is enough of a thrill for a lot of people to motivate the usage. ;-)
00:02	amalloy	nice
00:03	carllerche	I'm trying to write a connection pool, would it be better to represent it as an atom -> { "hostname" PersistentQueue } or maybe ref -> { "hostname" ref -> PersistentQueue } and then use dosync, or maybe a ref -> { "hostname PersistentQueue } directly and still use dosync?
00:04	amalloy	i can't think of a good reason to have a ref of a map of refs
00:06	choffstein	dnolen: when you say coordinating changes between data, what exactly do you mean? In a concurrent sense -- like a database?
00:06	dnolen	choffstein: yes.
00:06	dnolen	choffstein: dosync is like a db transaction
00:07	choffstein	dnolen: well, then it might make sense for my 'sessions' to be refs then, right, since those would be used across website users?
00:07	choffstein	whereas something that is specific to an individual session that will only be touched by a user and is just being used for serialization can be an atom
00:07	choffstein	?
00:09	dnolen	choffstein: dosync if there are not two peices of data involved doesn't make sense, to me at least. dosync is about changing > 1 refs.
00:10	choffstein	Annnnddd that makes a whole lot more sense now.
00:10	carllerche	amalloy: well, if trying to modify the individual queues becomes highly contended, wouldn't that loosen up the number of transactions that need to be restarted?
00:10	choffstein	so if I had a list of refs and I wanted to alter them all, I would wrap it with a dosync?
00:11	carllerche	(i haven't actually gotten around to using refs yet, so I don't know)
00:11	dnolen	choffstein: yes, but you want to control the scope of a transaction, better for a transaction to try to change two rather than ten refs at the same time.
00:11	choffstein	hmmm. I think i'll leave transactions alone for a little while :D
00:11	choffstein	I think i'm pretty happy with my horrible hacking for this evening.
00:12	amalloy	your use of the word "pooling" implies, to me, a fixed-size pool, so you never need to alter the top-level structure. it can just be an immutable map of (somethings) to (refs of connections)
00:12	dnolen	carllerche: I don't know much about efficient connection pools, I would look at how other people have done it. atoms and and refs have costs. but maybe efficiency is not a big concern in your case.
00:12	carllerche	amalloy: I'm actually building an HTTP reverse proxy that could have arbitrary end points
00:13	carllerche	so, basically my goal is to determine the total number of open connections that can be held at once (in the thousands) and build an LRU that can manage that
00:13	amalloy	okay...
00:14	amalloy	i'm hearing you say "yes, i have a fixed-size map"
00:14	choffstein	alright. time for bed before my brain melts. later all.
00:15	carllerche	amalloy: well, the keys can't be predetermined... it would be based on usage
00:15	carllerche	aka, i can't preallocate the connections
00:17	carllerche	i guess i could try the various options and see what works best
00:18	carllerche	although, i wonder if i could just implement it as commutative operations
00:19	carllerche	amalloy: so, what you are saying is that a ref to a map of refs is just crazy talk?
00:19	amalloy	yes. i have violent reactions to overuse of mutable state, so take that with a grain of salt though
00:20	amalloy	rata convinced me an atom of a map of agents made sense, though, at some point
00:21	Apage43	do agents have any ordering guarantees?
00:22	cemerick	carllerche: I presume that any talk of refs in conjunction with IO stuffs is crazy. Transactions will be retried. IO operations should not be retried. :-)
00:22	amalloy	Apage43: all requests from thread X will be processed in the order X sent them
00:22	Apage43	k
00:22	Apage43	i figured that'd be the case, just didn't remember
00:23	Apage43	cemerick: the commutative part (if using commute) won't be though
00:24	carllerche	cemerick: right... this is just for some structure that can store / retrieve objects
00:24	carllerche	no IO operations
00:37	carllerche	i'm confused about commute, is it possible for the retval of commute to be different from the value the ref gets set to?
01:16	Apage43	carllerche is gone
01:16	Apage43	but yes
01:17	Apage43	or rather
01:18	Apage43	well, it barely matters.
01:20	tomoj	I'm interested
02:58	stirfoo	does this profile macro look correct? http://paste.lisp.org/display/121658
02:59	stirfoo	the thing that bugs me is a given entry function shows less time than functions called by that entry function
03:01	clgv	stirfoo: the initial let looks fine. dont forget about lazy evaluation which can cause your functions to return fast since the real evaluation is postponed to the time the entry in the lazy seq is read
03:01	stirfoo	clgv: yes, that's something I haven't gotten a grip on yet, lazyness
03:02	clgv	your if-let has a different meaning than you might think
03:02	stirfoo	oh? do tell
03:04	clgv	that might work as well: ##(if-let [[a b] [nil nil]] [a b] 'else)
03:04	clgv	but it seems that doesnt matter in the remaining code
03:04	sexpbot	⟹ [nil nil]
03:05	clgv	summarizing: the code looks ok
03:08	stirfoo	ok, thanks clgv. Is the actual book 'joy of clojure' available yet? I know I can get a pdf. Haven't checked their site in a while.
03:08	clgv	stirfoo: yes it is
03:09	stirfoo	awesome
03:09	clgv	even on amazon now ;)
03:10	ambrosebs	mine just came in the mail
03:10	ambrosebs	love the guy on the cover
03:11	stirfoo	I read one or two of the freebee chapters a while back. Seemed like a well written book.
03:11	ambrosebs	I ordered "Learn you a haskell for great good", which has a blue elephant on the front... two fun covers with fun titles :)
03:12	stirfoo	Did Duane draw the elephant? (scheme joke)
03:14	ambrosebs	whoosh :P
03:16	ambrosebs	on the way to work this morning I was thinking if "The Joy of Java" would pop up in some form xD
03:17	ambrosebs	the only cover I've seen that advocates java as "fun" is the Pragmatic Programmers' Stripes book
03:17	ambrosebs	subtitled: "...and Java web development is fun again!"
03:17	ambrosebs	I laughed
03:17	ambrosebs	still, good book, good framework.
03:30	amalloy	tomoj: (commute) sets the ref to some temporary value for within your transaction, and returns that value. when you go to commit your transaction, if anyone else has altered/commuted that ref in the meantime, the stm re-performs the commute function with the new ref value and commits that
03:30	amalloy	it doesn't have to retry the transaction or tell you about the new value at all, because you told it commuting was okay
03:31	amalloy	so it is possible for (commute) to return a value that the ref never actually has, outside of your snapshot fantasy-land
04:02	clgv	Is it possible to combine two different plots with different scales in on Incanter chart? e.g. one scale on the left the other on the right?
04:03	clgv	*one
04:21	pyr	hi
04:23	pyr	I'm facing a weird use case with leiningen. How do I integrate jars which are not in any maven repo ?
04:28	pyr	I could put them in lib/ but every lein clean flushes them out
04:29	clgv	pyr: just add ":disable-implicit-clean true" to your project.clj
04:30	pyr	'k thanks
07:11	ordnungswidrig1	print-dup causes records to be dumped as #=foo.BarRecord/create {:a 1 :b 2 :c 3} how to I dump records so that load-string will read them?
07:43	thorwil	ordnungswidrig: isn't read meant to used for such dumps?
07:44	ordnungswidrig	thorwil: the reader doesn't support record literals yet
07:44	ordnungswidrig	thorwil: the need of importing the record class makes is worse
08:09	clgv	ordnungswidrig: you could dump them as normal maps and read those maps and assoc them...
08:09	ordnungswidrig	clgv: no so easy because you need some reflection to initialize an empty record.
08:09	ordnungswidrig	clgv: but certainly possible
08:11	clgv	ordnungswidrig: oh ok. I assumed you will know the record type at the time you want to read it
08:13	ordnungswidrig	clgv: no, but I can flip it into a map, like (defrecord Foo [a b c]) and (Foo. 1 2 3) -> {::type "some-ns/Foo" :a 1 :b 2 :c 3 }
08:14	ordnungswidrig	clgv: on read time i can transform back
08:14	clgv	ordnungswidrig: I know ;) but it's less code without the reflection part and thus easier ;)
08:16	clgv	ordnungswidrig: humm why not write (Foo. 1 2 3) to file? maybe with namespace associated?
08:30	fliebel	dnolen: I'm in the train, read the little paper. The syntax is indeed weird. What of this all is most relevant to your plan?
08:30	dnolen	the pattern matching paper?
08:30	dnolen	fliebel: ^
08:32	fliebel	yea
08:32	fliebel	uhm, no, well... the one with ml
08:34	dnolen	fliebel: yeah that's the pattern matching paper. the paper shows you how to do pattern matching efficiently, the implementation allows you to break apart the compilation and analysis/optimization steps.
08:35	dnolen	which makes the implementation a lot simpler/cleaner than previous papers on papers on pattern matching.
08:35	david`	what's the difference between (case x) and (condp = x)?
08:36	dnolen	david`: case does not test possibilities.
08:36	fliebel	dnolen: Ah, I see. And you want to use Logos to generate the maximum sharing shallow stuff?
08:37	david`	I see, so the "= x" can be changed to really any test condition
08:38	david`	like condp some [1 2 3 4]
08:38	dnolen	fliebel: no I plan on implementing what's described in the pattern matching paper as is. but pattern matching has a problem. It's closed, you can't add stuff later. Also order matters, it's easy to make a mistake and write broken pattern.
08:39	dnolen	fliebel: keeping things open is unrelated to the logic engine, however automatically reordering clauses is something the logic engine can do.
08:40	dnolen	fliebel: consider (defm foo [x] :guard (even? x))
08:40	dnolen	fliebel: then consider that someone else wants to add (defm foo [0]) after the fact.
08:40	dnolen	fliebel: because the first one was defined first, the second one will never be reached.
08:41	dnolen	fliebel: we can fix that with a logic engine.
08:41	fliebel	oh, so you are just implementing these pares really. I thought you want to tell logos the properties of the tree ansd say "go do it"
08:43	dnolen	fliebel: it will store properties of the tree, but it's there to solve implication issues like the one above.
08:43	fliebel	oh, okay. Interestng. I need to go now though, my train isn't going where it should.
08:48	dnolen	david`: yes.
08:55	david`	kewl
10:12	devn	dnolen: intensely awesome work
10:12	clgv	(apply third-party-macro param1 param2 options) does not work. can I work around that somehow?
10:13	dnolen	devn: heh, at this point we're still in the realm of ideas ;)
10:14	devn	dnolen: even still, the germ of the idea is exciting
10:14	devn	dnolen: is there video anywhere of this LispNYC talk you gave?
10:15	apgwoz	devn: you have to move to nyc to see it
10:15	apgwoz	sorry, them's the rules
10:15	devn	apgwoz: how big is your apartment?
10:15	apgwoz	big enough for my wife, a baby (soon) and myself. not for you
10:15	apgwoz	:)
10:15	devn	alls i've got is this here stick and bindle
10:16	apgwoz	edw: chicken scheme can speak to slime now
10:18	devn	apgwoz: you bring up an important point. i'd like a move sometime soon.
10:18	apgwoz	madison isn't happening enough for you?
10:18	Ramblurr	do most people use the stable clojure release or use the live git version?
10:18	apgwoz	devn: meetup is hiring, though there's only a tiny tiny tiny bit of clojure code at the moment.
10:18	devn	I really like Madison, but once my girlfriend is finished with school next semester we're sort of planning on a move East or West
10:19	apgwoz	yeah, i visited madison last september, nice place.
10:20	devn	there's going to be a madison ruby conference this year -- excuse for you to make a visit
10:21	devn	apgwoz: either way, maybe ill come out to NYC for a weekend and see some friends, drop by the LispNYC meetup
10:21	devn	Ramblurr: depends on what you want to do
10:22	devn	Ramblurr: id say most are on stable, though
10:24	apgwoz	devn: but i don't really like ruby, so that's a reason to avoid madison :)
10:26	Ramblurr	devn: ah, hm. I asked because my 1.2.0 jar seems to be missing functions: join, blank?
10:27	devn	Ramblurr: what's your setup?
10:27	Ramblurr	devn: oh, i have to "use" the string module heh
10:28	clgv	how can I avoid this: (eval `(xy-plot ~x ~first-col ~@options)) ???
10:28	clgv	xy-plot is a macro unfortunately sothat I can't use apply
10:28	Ramblurr	devn: is this error expected when doing (use 'clojure.string) ? WARNING: replace already refers to: #'clojure.core/replace in namespace: user, being replaced by: #'clojure.string/replace
10:29	devn	Ramblurr: yes.
10:29	devn	Ramblurr: are you just getting used to the idea of clojure's namespaces and such?
10:29	devn	Ramblurr: http://blog.8thlight.com/articles/2010/12/6/clojure-libs-and-namespaces-require-use-import-and-ns
10:29	pjstadig	clgv: write your own wrapper macro?
10:29	Ramblurr	devn: yea, this is my first encounter with them
10:30	Ramblurr	devn: thanks for the reading
10:30	devn	Ramblurr: not a problem. have fun
10:30	clgv	pjstadig: errmmm... how?
10:30	clgv	just extract the code over there?
10:31	pjstadig	yeah something like (defmacro xy-plot2 [x first-col & options] `(xy-plot ~x ~first-col ~@options))
10:32	pjstadig	eval + syntax-quote is essentially macro evaluation anyway
10:35	clgv	pjstadig: hmm I can't really get around it. I want to write a function but the option-handling forces me to write a macro if I do not use eval + syntay-quote
10:35	pjstadig	where is xy-plot from and why is it a macro?
10:37	clgv	it's from Incanter
10:37	clgv	I dont know why it is a macro
10:37	clgv	it just seems to do some default value handling for options
10:38	sritchie	here's the source -- https://github.com/liebke/incanter/blob/8736bc3cae44491172031b381c6e165c0bd1139c/modules/incanter-charts/src/incanter/charts.clj#L984
10:38	clgv	sritchie: already looking at it ;)
10:39	sritchie	clgv: just trying to live up to clojurebot's helpfulness :)
10:40	Ramblurr	o_0 I'm getting different results from a function when i call it with dotrace or by itself
10:43	chouser	Ramblurr: is dotrace printing return values of functions or their arguments? or just listing the names of functions being called?
10:44	Ramblurr	chouser: both
10:44	Ramblurr	chouser: preparing a snippet, one sec
10:44	pjstadig	clgv: you could do something icky like (apply xy-plot* x first-col @#'incanter.charts/create-xy-plot options)
10:45	chouser	Ramblurr: if it prints return values or args, it may be forcing lazy sequences that wouldn't otherwise be realized.
10:46	Ramblurr	chouser: oh, i see
10:46	clgv	pjstadig: hmmm I guess I'll write the whole thing as macro
10:48	Ramblurr	chouser: http://pastebin.com/aALcDt1y
10:51	Ramblurr	chouser: and here is the output different http://pastebin.com/QXvHVige Would you say this is a case of lazy seqs being evaled?
10:59	pyr	hi, do you any use cases where clojure.contrib.sql's with-query-results could yield an exception because distinct? was called with no arguments
11:15	mec	(let [[a b c] (if t [1 2 3] [2 3 4])] ...) vs (let [foo (fn [a b c])] (if t (foo 1 2 3) (foo 2 3 4))
11:20	semperos	is there any reason to use clojure.string/escape over clojure.string/replace?
11:20	kzar	I'm trying to get my head around Enlive, I've made a snippet to add stylesheet links to my page's layout. For my snippet selector I've used [:link {:rel "stylesheet"}], I've then done used set-attr on [:link] in an attempt to set the href of the stylesheet. I can't get it working though. Also it seems weird that I have to define my template to point to layout.html and then point my css including snippet at the layout
11:20	kzar	.html template too. I get the feeling I've totally misunderstood something here?
11:20	semperos	in microbenchmark, clojure.string/replace performed better
11:21	semperos	other than the need to replace more than one thing in a single swipe
11:26	manutter	kzar: do you have a gist?
11:26	kzar	manutter: http://paste.lisp.org/display/121664
11:27	kzar	manutter: The css-include part is what's confusing me although it's likely all backwards
11:42	edw	In theory, shouldn't re-factoring conserve the does-it-work? property?
11:54	kzar	manutter: I've cracked a couple of problems, just got to figure out how to get it populating the href properly now
12:07	kzar	ah I've cracked it :)
12:14	manutter	Man, bosses can be so demanding at times :\
12:14	manutter	Good, I'm glad you got it, I got called away
12:15	kzar	no worries! I know what that's like heh
12:22	TimMc	edw: Yeah, and as long as it doesn't affect your API, your automated tests should all still pass.
12:55	TimMc	(You are writing tests, yes? :-P)
12:55	semperos	anyone know proper spec for clojure.contrib.sql for a DATETIME column? tried :datetime
12:56	semperos	sorry, for the clojure.contrib.sql/create-table fn
13:11	ataggart	stuarthalloway: free to discuss the bit-ops stuff?
13:12	stuarthalloway	yep
13:13	ataggart	read your responses, everything looks as I expected. ONe question: what's the point of having Object overloads if everything gets treated as a long anyway?
13:14	stuarthalloway	I think you will find that there are code paths where things come in as objects
13:14	stuarthalloway	you can try long only and see what happens :-)
13:14	ataggart	I have: https://github.com/ataggart/clojure/commits/bit-ops
13:14	ataggart	the compiler knows how to push numbers to long primitives
13:16	ataggart	if that commit looks good, I'll make a patch and attach it to 767
13:17	stuarthalloway	the core.clj changes in that commit seem related to something else ?
13:17	stuarthalloway	reviewing the numbers.java changes now
13:18	ataggart	the change in core.clj is because where the exception on passing a double to even? went away
13:20	stuarthalloway	seems like exception is the right behavior
13:20	ataggart	it used to be thrown via bitAnn on line 1201 in Numbers
13:20	stuarthalloway	what does it mean for a double to be even?
13:21	ataggart	yep, it's always thrown an exception on non-integer nums
13:21	ataggart	just changed the location
13:21	stuarthalloway	let's leave that out of the patch
13:22	stuarthalloway	do you know if the shiftLeftInt variants are ever used anywhere?
13:22	ataggart	they are not
13:23	ataggart	I'm not clear on what you want left out of the patch. even? is supposed to throw an exception; that exception used to be thrown by bitAnd which used to throw it in bitOps, bit bitOps is gone, so someone needs to throw the exception when even? is called with a non-integer
13:24	stuarthalloway	what happens without the change in core?
13:24	ataggart	tests failed, don't recall what
13:24	ataggart	lemme see
13:25	stuarthalloway	thanks, trying it here as well
13:25	stuarthalloway	did you see that #426 (case) finally got in?
13:26	ataggart	I'm not a religious man, but....
13:26	ataggart	what was the voodoo you used to find those bad numbers?
13:27	stuarthalloway	ataggart: I thought Alan told you
13:28	stuarthalloway	https://github.com/clojure/test.generative
13:28	ataggart	he mentioned you had some framework, ah yeah nice
13:28	stuarthalloway	the tests are still in there (under examples)
13:28	aredington	Alan was probably avoiding stealing Stu's thunder on dropping that bombshell
13:32	ataggart	sigh, the compiler is automatically casting from non-integers to long
13:32	aredington	What kind of non-integers ?
13:32	ataggart	ratios, doubles
13:33	ataggart	anythign that's not a long or int
13:34	ataggart	when the param is long, but the arg is neither long nor int, the param gets treated as an object and then automatically cast to the param type
13:35	ataggart	I can manually deal with all the type checking, but... ugh
13:36	stuarthalloway	not sure I am totally following you without seeing it run -- going to build it now
13:36	stuarthalloway	sorry slow -- I am multitasking several numerics tasks here
13:36	ataggart	ya sry, I can see it since my head has been in the compiler for a few months now
13:37	ataggart	anyway, it's a problem with bit-ops really, since (bit-and 1.5 1) is coming back 1
13:37	ataggart	because that 1.5 is getting truncated to a long
13:38	ataggart	by the compiler
13:38	ataggart	don't waste your time on it, lemme fix that
13:38	stuarthalloway	so would the Object/long and long/Object variants fix that?
13:40	ataggart	they wouldn't, but for (bit-and double long) the compiler would choose and(Object, long) and we can perform manual type checking, which is what bitOps used to do
13:40	ataggart	it's a deficiency in the compiler
13:40	ataggart	imo
13:40	stuarthalloway	fair enough, but let's get this done
13:40	ataggart	yup, half way there
13:52	dakrone	stuarthalloway: response to your email, I need a float for a test as such: (is (= "3.14" (json/generate-string (float 3.14)))), but fails with the 1.3 stuff
13:52	dakrone	for testing a lib that has float methods
13:53	stuarthalloway	dakrone: where is the float method?
13:54	stuarthalloway	called inside json/generate-string somewhere?
13:54	dakrone	inside the generater, in a condp looking something like "... Float (.writeNumber jg ^Float obj)"
13:54	dakrone	yes
13:55	stuarthalloway	and you need float fidelity, so double promotion would be a bug?
13:56	ataggart	cough445 fixes thatcough
13:56	dakrone	yes, otherwise I get the error that it can't find a correct method
13:57	stuarthalloway	let me see if I have the general issue right: you have a serialization framework that depends on access to the different Java primitive types in order to drive different semantics
13:58	dakrone	stuarthalloway: http://jackson.codehaus.org/1.7.4/javadoc/org/codehaus/jackson/JsonGenerator.html#writeNumber(int) there are 7 .writeNumber methods, which can be treated differently internally depending on class
13:59	dakrone	I have no way to guarentee that .writeNumber(double) behaves the same as .writeNumber(float)
13:59	stuarthalloway	dakrone: so you could get there by calling them directly (with float hinting) but any indirection (e.g. a Clojure fn) makes things doubles
14:00	@rhickey	dakrone: calling such an overloaded thing requires coercions
14:00	@rhickey	coercions are not hints
14:01	stuarthalloway	rhickey: how does that work when there is a Clojure fn call between the float the Java method to be called
14:01	dakrone	rhickey: If I'm doing condp with dispatch on type though, by that point the compiler's already made it a double
14:01	@rhickey	stuarthalloway: like what?
14:02	@rhickey	dakrone: condp doesn't do type dispatch on primitives
14:02	semperos	sorry to re-ask, had to leave an hour ago
14:02	@rhickey	if you want a boxed Float make one
14:02	semperos	does anyone know how to use clojure.contrib.sql/create-table with datetime columns?
14:02	@rhickey	(float x) does not make a Float
14:03	dakrone	no, understandable, how should I dispatch in a function then on primative, and call it from a test if in the test I use (float 3.14) and by the time it reaches a dispatch it's a double?
14:04	stuarthalloway	dakrone: (Float. 3.14)
14:04	@rhickey	stuarthalloway: you can't route floats around, Clojure doesn't have primitive floats
14:04	ataggart	it could...
14:04	stuarthalloway	dakrone: when you are making a fn call you are using objects anyway
14:04	@rhickey	(float x) produces a float for immediate consumption by a Java thing that takes a float
14:04	stuarthalloway	ataggart: go finish that patch :-)
14:05	ataggart	aye sir
14:05	dakrone	okay, then I will not be able to handle doing json enconding of java methods that could return floats
14:05	stuarthalloway	dakrone: yes, you could, with (Float. )
14:05	@rhickey	dakrone: I don't see why not
14:05	dakrone	(json/encode (.methodThatReturnsAPrimativeFloat foo)), at that point it would be a float, how can I dispatch on it?
14:06	@rhickey	ataggart: no, it won't
14:06	ataggart	stuarthalloway: https://github.com/ataggart/clojure/commit/496135716ab8687ba4373ca9799db57ed6638060
14:06	hiredman	if you call a java method and it returns X, but you aren't sure what type X is, how do you determine the type of X in such a way that avoids boxing X as a different type?
14:06	dakrone	I can dispatch in encode in a condp with Float, but it's not a Float and I need to dispatch in encode on what type it is
14:07	pjstadig	right, it's not interop if it only goes one way, if values returned from java are converted to doubles, then there's no way to maintain fidelity of floats to/from java
14:07	ataggart	rhickey: every fall to a float-taking method is effectively called like Foo.bar((float)(double)myFloat). That causes unexpected changes in value, and can be easily fixed.
14:07	@rhickey	dakrone: how would you write json/encode in java?
14:09	hiredman	dakrone: you happen to have it also written up in java, yes?
14:09	stuarthalloway	ataggart: given no plan to support big ints, can we not replace bitOpsCast with a simple cast to long?
14:09	@rhickey	call RT.box then
14:10	hiredman	rhickey: on which side of the fn call?
14:10	ataggart	stuarthalloway: the choices are unchecked cast to long, checked cast to long which accepts all numic categories (i.e. RT.longCast(Object)), or the category-specific checked cast I added.
14:11	hiredman	calling RT/box inside the fn is too late (conversions have happened) calling it outside means all callers of encode have to call (encode (RT/box x))
14:11	dakrone	rhickey: In java the point would be moot since there would no longer be a wrapper in the middle, you would call the generate method directly and java would route to the right place
14:11	kzar	Does anyone else find that sometimes emacs stops displaying function arguments in the mini buffer after a while?
14:11	@rhickey	hiredman: was speaking to json/encode
14:12	hiredman	uh, I thought I was too?
14:12	@rhickey	I'm not particularly attached to floats as Doubles if itsa big problem for people. short/int/long as Long is a bigger deal
14:13	semperos	kzar: you using slime/swank?
14:13	hiredman	given the lack of floating point weirdness I can't imagine it would be a big deal
14:13	kzar	semperos: Yea, it works fine but just sometimes after a while it breaks
14:13	@rhickey	dakrone: I don't understand
14:14	kzar	semperos: It's probably my god-awful code causing it to seppuku heh
14:14	no_mind	I have serialzed a map and stored in a string to dump in a db. NowI want to deserialize the sw do I do it ? map. Hotring to
14:14	semperos	kzar: I've had similar happen; sometimes I forget to compile and load ns's
14:14	semperos	sometimes it just needs a classic reboot :)
14:15	raek	no_mind: are you talking about pr-str and read-string?
14:16	dakrone	rhickey: In java, I'd encode directly and be happy, no special forms or rewriting required. In clojure, I need to dispatch on things like vectors, lists, maps and such to translate them to an encodeable-format before passing them down to the java methods, once I have a list though, I need to dispatch on each element in the list, with could be a Number, so I do a condp and dispatch on Number. I do this recursively, so have a co
14:16	dakrone	does that kinda explain it?
14:16	no_mind	raek: dont know what they are ? I serialized the string with print-dup
14:17	stuarthalloway	rhickey: should (bit-and 1N 1) throw an exception, or coerce to primitive long and proceed?
14:17	raek	,(let [m {:a "1", :b "2"}] [m (pr-str m) (read-string (pr-str m))])
14:17	clojurebot	[{:a "1", :b "2"} "{:a \"1\", :b \"2\"}" {:a "1", :b "2"}]
14:18	amalloy	dakrone: fyi your huge-long message was too long for irc and got truncated at "have a co"
14:19	pjstadig	upcasting bytes, shorts, ints as longs makes sense, because those types are precise and you can just chop off some data to down cast it without any loss
14:19	@rhickey	stuarthalloway: if bit-and is defined for longs only then that has the same answer as should any long-taking method accept BigInts (i.e. the converson question we talked about this morning)
14:19	pjstadig	as we've seen upcasting from float to double produces slightly different values
14:19	raek	no_mind: if a value is built only of strings, keywords, symbols, lists, vectors, maps etc (i.e. only object that are part of the clojure syntax), then you can use pr-str to turn it into a string and use read-string for the reverse
14:19	pjstadig	floats are not exactly a subset of doubles
14:20	no_mind	ok
14:20	dakrone	rhickey: http://p.writequit.org/explain.html
14:20	dakrone	amalloy: thanks for the heads up
14:20	stuarthalloway	rhickey: what about even?, which (as implementation detail IMO) is implemented with bitops
14:20	@rhickey	dakrone: that's getting bigger and bigger - make the problem smaller - what would the signature of encode be in Java?
14:22	dakrone	rhickey: that's what I'm saying, there would be no need for encode in java
14:22	dakrone	It's entirely possible that I am Doing It Wrong (tm)
14:22	dakrone	will look and get back to you
14:23	@rhickey	stuarthalloway: what about it?
14:24	@rhickey	stuarthalloway: should even? work for bigints? - of course
14:25	stuarthalloway	rhickey: right on, so the implementation has to change, since bit-and will not work for big ints
14:25	@rhickey	stuarthalloway: sounds right
14:28	stuarthalloway	totally separate issue: running Clojure in IDEA for debugging
14:28	scgilardi	would the change be to use BigInteger's "and" method directly? avoiding a division or div/rem operation for even? would be nice.
14:29	stuarthalloway	I am stuck because the basic compilation doesn't put the version resource in the right place, causing an NPE reading the version string
14:29	aredington	(= (mod <num> 2) 0) should work transparently across all integer values
14:29	stuarthalloway	I can think of a dozen workarounds or fixes, any strong opinions? Or does anybody have a workflow (not including ant or maven) for interactive debugging?
14:30	hiredman	I have a lein'ized clojure build
14:30	fogus`	stuarthalloway: sed was my Huckleberry. It sucked
14:31	scgilardi	aredington: mod is division-y
14:31	hiredman	I rember futzing with the version file issue
14:31	stuarthalloway	fogus` : why is there a backtick in your name?
14:31	hiredman	dunno how well it would work in IDEA
14:31	fogus`	stuarthalloway: Some other fogus took my name
14:31	aredington	too many fogii
14:31	stuarthalloway	fogus` : poor Optimus had the same problem
14:31	aredington	that's right you can't outtype me
14:32	redinger	fogi?
14:32	fogus`	fogen
14:32	optimus`	not funny guys
14:33	hiredman	https://github.com/hiredman/clojure/commit/0a1c064c767991004b94aa796181aed111c98f34
14:34	stuarthalloway	hiredman: zoinks
14:35	hiredman	oh, actually now I remember it doesn't build with a stock lein either
14:35	hiredman	damn
14:35	hiredman	lein puts ./src on the classpath which breaks for building clojure
14:36	bulters	alandipert: I was just wondering who would be optimus prime then.
14:36	mec	anyone know the O of adding to a sorted set?
14:37	chouser	mec: there's a nice chart for that...
14:37	stuarthalloway	ataggart: re http://dev.clojure.org/jira/browse/CLJ-781, you need to put your shorts in the first branch of the if
14:38	bulters	mec: ordered? then it\s usually a O(log n/log r) op
14:38	stuarthalloway	ataggart: otherwise they fall through and get converted to doubles, then longs.
14:39	ataggart	stuarthalloway: what are you referring to?
14:39	ataggart	the patch on 781?
14:39	amalloy	mec: log2(n)
14:39	mec	thanks all
14:39	stuarthalloway	ataggart, sorry, wrong link: http://dev.clojure.org/jira/browse/CLJ-782
14:40	stuarthalloway	shorts used to fall down to the longCast at the bottom
14:40	fbru02	stuarthalloway: Hey ! Can you please take a look at http://dev.clojure.org/jira/browse/CLJ-730 ?
14:41	stuarthalloway	fbur02: we'll take a look, but lower priority than bugs
14:42	stuarthalloway	ataggart: if you are working on the bit-ops patch, I can tweak 782 and submit it to Rich
14:43	@rhickey	https://github.com/clojure/clojure/commit/6fb09f402c5448070a2efc64ebd64285480b263f
14:43	ataggart	ok, just add Short and Byte to the first if
14:44	stuarthalloway	rhickey: performance tweaking question for you
14:44	@rhickey	stuarthalloway: ok
14:44	stuarthalloway	ataggart's patch http://dev.clojure.org/jira/browse/CLJ-782 correctly splits out a new path in longCast
14:44	hiredman	the passes are Parser/paser and Expr/(emit\|eval)?
14:44	hiredman	parse
14:45	stuarthalloway	but that split implies the need to also split out short and byte, which used to fall to the bottom
14:45	stuarthalloway	is it important that those conditionals be away from the top, so the hot path (int and long) at the top doesn't pick up two more checks?
14:45	stuarthalloway	or does the short/byte case need to be handled further down
14:46	@rhickey	stuarthalloway: can't read these damn context-less patches
14:46	@rhickey	stuarthalloway: but yes, prioritize long and int please
14:47	fbru02	stuarthalloway: thanks :)
14:47	stuarthalloway	rhickey: apply the patch locally and then view in IDEA :-)
14:47	@rhickey	stuarthalloway: applying patches in order to see what they do is a huge time suck
14:47	ataggart	stuarthalloway: posted link to updated bit-ops commit for your review
14:48	stuarthalloway	ataggart: can you move the short/byte check out of the first if, down later in the fn? (see discussion with rhickey above)
14:48	ataggart	stand by
14:52	ataggart	and updated cast fix: https://github.com/ataggart/clojure/commit/59bc3b2010ae7b0c8efb77e82939118b2f435045
14:54	stuarthalloway	ataggart: https://github.com/ataggart/clojure/commit/59bc3b2010ae7b0c8efb77e82939118b2f435045 looks good. please put the patch on the ticket and I will screen it
14:55	stuarthalloway	ataggart: still looking at the bit-ops patch and wondering how best to implement even?
14:55	aredington	checking even let's BigIntegers in the door which are then going to be cast to long for bit-and
14:56	ataggart	that shouldn't affect the eveness
14:56	ataggart	the LSB is still going to be 1 or 0 irrespective of the truncation
14:57	stuarthalloway	ataggart: so we should need unchecked-long instead of long?
14:57	ataggart	yup
14:57	ataggart	stand by
14:57	scottj	is there a shorter version of &&(reduce #(update-in %1 [%2] (fnil inc 0)) {} [1 2 3 1 2 1])
14:58	amalloy	scottj: ##, not &&
14:58	scottj	##(reduce #(update-in %1 [%2] (fnil inc 0)) {} [1 2 3 1 2 1])
14:58	sexpbot	⟹ {3 1, 2 2, 1 3}
14:58	amalloy	&(frequencies [1 2 3 1 2 1])
14:58	sexpbot	⟹ {1 3, 2 2, 3 1}
14:58	dakrone	rhickey: I was able to work around the primative problem, I was indeed doing it not-wrong-but-not-the-best-way
14:58	dakrone	thanks for the help
14:58	scottj	amalloy: thanks
14:59	amalloy	unless you're looking for a better way to reimplement frequencies
14:59	@rhickey	dakrone: I wasn't much help, but glad you are unstuck :)
15:00	amalloy	scottj: i think your original question is how i solved http://4clojure.com/problem/55
15:09	choffstein	Hey all! I have a question: I am basically trying to perform a map, but also while using an accumulator. So its sort of like reductions, but I don't want the accumulator recorded. Is this idea possible? I think it can be done using a recursive solution, but I was wondering if it was a built in idiom
15:09	opqdonut_	:t mapAccumL
15:10	opqdonut_	oh, sorry, I thought I was in #haskell
15:10	opqdonut_	no, I don
15:10	opqdonut_	't think I've seen a function for that in the standard library
15:10	opqdonut_	but you might get a nice solution with map + reduce
15:12	choffstein	yeah, I didn't think there would be
15:13	opqdonut_	IMO reducing with a slightly intricate function is better than a custom recursive solution
15:13	choffstein	well, what I need to do is basically keep "track" of a previous label and carry that label through to all nil labels until i hit a new label
15:14	opqdonut_	that
15:14	bulters	I have a dependency in a leiningen project (in this case org.clojars.liebke/congomongo "1.0.0") and I try to 'use' it in a slime session I get a compile error (FileNotFoundException)
15:14	opqdonut_	certainly sounds doable
15:14	bulters	but checking the classpath, congomongo-1.0.0 is on it.
15:14	opqdonut_	(how come I keep hitting my return key by accident all the time?)
15:14	stuarthalloway	rhickey, ataggart: http://dev.clojure.org/jira/browse/CLJ-782 is screened
15:15	amalloy	choffstein: so use reductions, with a two-part accumulator: [the-map-value current-label]
15:15	bulters	any ideas what I'm doing wrong?
15:15	amalloy	then you can (map first (reductions (fn [[_ label]] (...return a vector of [map-value new-label]...))))
15:16	ataggart	rhickey has left the channel
15:16	amalloy	sorry, should be (fn [[_ label] current-input] ...)
15:17	choffstein	amalloy: that's what I was going to do, I just didn't know if that was idiomatic clojure
15:18	amalloy	choffstein: i tend to overuse the HOFs for cases when writing a lazy-seq by hand would be clearer and/or easier. this might be such a case
15:19	raek	bulters: did you check the classpath from within the clojure instance that could not use it?
15:19	choffstein	HOFs?
15:19	opqdonut_	higher order functions
15:19	opqdonut_	like map, reduce
15:19	bulters	raek: yup, it clearly lists lib/congomongo-1.0.0.jar
15:20	raek	what namespace are you trying to use?
15:21	bulters	raek: tried 'everything' congomongo, liebke.congomongo, org.clojars.liebke/congomongo
15:21	TimMc	clojurebot: HOFs are higher order functions
15:21	clojurebot	anonymous functions are functions with no names
15:21	TimMc	bah
15:21	TimMc	This bot can't conjugate.
15:22	raek	bulters: I don't think org.clojars.liebke is the official fork
15:22	Ramblurr	i'm having an issue where the results of dotrace are different than when i println the function's results :\
15:23	raek	bulters: in the jar, there's a namespace called somnium.congomongo
15:23	bulters	raek: trying somnium now
15:23	Ramblurr	unfortunately the dotrace result is the correct one
15:23	raek	bulters: docs semes to be here: https://github.com/somnium/congomongo
15:25	raek	bulters: but for some reason, there isn't any stable (non-snapshot) version available
15:25	bulters	raek: my biggest hurdle I have so far in using clojure ;-)
15:27	raek	bulters: [congomongo "0.1.4-SNAPSHOT"] should work, but leiningen won't allow you to make a stable version of your project that depends on a snapshot version of a lib
15:27	raek	this is probably why liebke pushed a private version
15:29	bulters	raek: Luckily I'm not releasing anything for the next few years
15:29	bulters	;-)
15:29	bulters	thanks, it compiles :D
15:49	mec	how come some places in core.clj call (drop 1 ...) instead of just next?
15:50	rak85	hi, guys
15:50	rak85	a ! in the end of a function name is some kind of convention?
15:51	TimMc	rak85: Yeah, it usually indicates mutation.
15:51	TimMc	Specifically, things that aren't safe to call in a transaction.
15:51	bulters	TimMc: So stuff that has side effects go to a x! function?
15:52	TimMc	bulters: I think ! is usually used to make it clear when it wouldn't otherwise be obvious.
15:52	bulters	ok, so store-blah is fairly obvious :P
15:52	TimMc	bulters: compare assoc vs. assoc! for instance
15:53	bulters	same as in ruby, one variant that is non 'destructive' and one that is.
15:53	mec	looks like its mainly for things that muck with atoms and transients
15:53	mec	and vars
15:56	rak85	thanks everyone
15:58	dnolen	bulters: not quite, assoc! can only be used transients, and even then those can't be bashed in place.
16:01	bulters	dnolen: I have no idea what transients are... yet; guess it's google time
16:09	mattmitchell	i have what i think is a byte array: #<byte[] [B@ff22be7>
16:09	mattmitchell	how do a pull out the items in that object?
16:09	mattmitchell	is the duck streams contrib required?
16:09	ataggart	,(aget (byte-array 1) 0)
16:09	clojurebot	0
16:10	dnolen	,(nth (byte-array 1) 0)
16:10	clojurebot	0
16:10	ataggart	nth uses a seq though
16:10	ataggart	iirc
16:11	mattmitchell	ataggart: thanks! trying that out now...
16:12	dnolen	ataggart: https://github.com/clojure/clojure/blob/master/src/jvm/clojure/lang/RT.java#L746
16:12	ataggart	yeah, so not a seq, but still more involved than aget
16:13	dnolen	ataggart: true
16:14	raek	,(into-array [1 2 3])
16:14	clojurebot	#<Integer[] [Ljava.lang.Integer;@e8873a>
16:14	raek	,(seq (into-array [1 2 3]))
16:14	clojurebot	(1 2 3)
16:14	mattmitchell	ok, so i could turn the byte array into a seq
16:14	dnolen	mattmitchell: if you don't care that you lose random access.
16:15	raek	mattmitchell: function that operate on sequences will call seq on the argument, so in most cases you can ommit seq
16:15	raek	,(map inc (into-array [1 2 3]))
16:15	clojurebot	(2 3 4)
16:15	mattmitchell	raek: ok cool
16:15	ataggart	(map inc (byte-array 3))
16:15	ataggart	,map inc (byte-array 3))
16:15	clojurebot	#<core$map clojure.core$map@b36022>
16:15	ataggart	bah
16:15	ataggart	,(map inc (byte-array 3))
16:15	clojurebot	(1 1 1)
16:16	ataggart	this is annying though: ##(type (aget (int-array 1) 0))
16:16	sexpbot	⟹ java.lang.Integer
16:17	ataggart	wait what
16:17	ataggart	ah 1.3.0 has that as a Long
16:20	kzar	This has a very real danger of being a bad idea, badly executed but can anyone spot what's wrong with this macro? http://paste.lisp.org/display/121675
16:21	raek	yup. all integer numbers are represented as Longs when they are boxed in 1.3
16:21	kzar	(I wanted it to just return nil on any exception.)
16:23	raek	kzar: you need to use gensym'ed symbols to bind values: (catch Throwable e# ...)
16:24	raek	otherwise it will be resolved, as if it was meant to refer to a global var
16:24	raek	,`foo
16:24	clojurebot	sandbox/foo
16:24	raek	,`foo#
16:24	clojurebot	foo__1290__auto__
16:24	raek	this is to avoid symbol capture
16:25	kzar	raek: So with # it's gensymed and then the variable ends up being bound inside the place where it's actually being used. Otherwise it's not gensymed and it ends up being global to the namespace, or at least it tries to be but because it's not present I (ironically) get an exception
16:26	ordnungswidrig	I'm looking for a way to serialize / dump a clojure value which consists of maps, list etc. but also refs, e.g. {:foo-by-id {1 (ref {:name "foo-1"}) 2 (ref {:name "foo-2"})}
16:27	ordnungswidrig	print-dup does not support refs :-(
16:27	raek	kzar: let (and also catch) simply requires the symbol to not have a namespace part (and refuses compilation if the rule is not followed)
16:28	raek	syntax-quote (`) simply adds namespace parts to all symbols (except for those representing special forms)
16:29	kzar	raek: Ah right I get you now
16:29	kzar	raek: Thanks :)
16:29	raek	but it won't add a namespace part if the symbol ends in #, instead it makes up a new unique symbol to avoid name collisions
16:37	amalloy	clojurebot: HOFs \|are\| higher order functions
16:37	clojurebot	Alles klar
16:37	amalloy	TimMc: ^
16:39	fliebel	dnolen: Sorry for leaving so abruptly earlier today. I've only just reached home :P Some crane drove through the catenary of the train I was supposed to take.
16:39	dnolen	fliebel: np.
16:41	fliebel	dnolen: That paper, it does not describe the actual pattern matching, does it? Just the underlying tree stuff.
16:42	dnolen	fliebel: ? what do you mean.
16:43	mattmitchell	wow i'm confused. i'm using the contrib.sql lib, and when i run a select w/a group_concat, the resulting field is a byte array. how the heck do i grab the actual values out of it? :\|
16:44	fliebel	dnolen: well, they just write _::[] to mean whatever that means. So besides implementing that paper for the efficient dispatch, you also need the actual pattern matcher, right?
16:50	mattmitchell	ok clojure.core/slurp does the trick!
16:55	dnolen	fliebel: sorry, stepped away for a second, the decision tree is the pattern matcher.
16:59	dnolen	fliebel: the predicate dispatch paper is all about building a decision tree with user definable predicates, the OCaml paper is about making a really, really efficient decision tree with the hard coded "predicates" that OCaml provides like _::[]. OCaml actually has guards which are like user definable predicates, but these are susceptible to ordering problems as I said before.
17:04	fliebel	dnolen: I too stepped away :) Umph, I understood little of the paper I guess.
17:04	dnolen	fliebel: I'm reading it for a 4th time now, it's starting to make sense.
17:05	fliebel	hehe :) okay, point made.
17:06	dnolen	fliebel: basically the gist of both papers is the same, the predicate dispatch comes from the perspective of OO and generic methods, the OCaml paper comes from the perspective of ML style pattern matching. But the methodology is very much the same, and the second paper really digs into how to make it very fast.
17:06	fliebel	does the other one also use that math syntax?
17:08	dnolen	fliebel: predicate dispatch perspective - we want pattern matching, but we want to be able add new patterns whenever we want. But they don't address the fact that new patterns might introduce ordering issues. So I want to the open-ness of predicate dispatch, the efficiency of ML pattern matching, and remove the ordering issue.
17:08	dnolen	fliebel: no.
17:08	fliebel	They seem to be theorizing about tree depth and sharing. Would it make sense to write a pattern JIT? I mean, let the naive one run a few iterations, and optimize 'hot paths'.
17:09	fliebel	In real life, some branches are more equal than others.
17:10	dnolen	fliebel: let the JVM do that for you.
17:11	dnolen	it's just byte code.
17:13	dnolen	fliebel: the other advantage with that paper is prior papers on ML pattern matching implementations are complex, while this paper presents a solution that's simpler to implement w/o losing on perf.
17:14	fliebel	dnolen: What I mean is that while these nice heuristics might figure out a tree that hash not to much decisions for all leaf nodes, there might be nodes that get accessed more frequently than others. So I was thinking you could shape the tree by usage, so that the common cases require few deciisions.
17:15	fliebel	dnolen: Yea, the mentioned that it is simple and still works for anything but pairs.
17:19	mattmitchell	what's the best way to convert a string "1" into an integer 1 ?
17:19	dnolen	fliebel: I know. a runtime optimization - so something I'd rather leave to JVM.
17:20	amalloy	&(read-string "1")
17:20	sexpbot	⟹ 1
17:22	mattmitchell	amalloy: perfect thanks
17:30	raek	mattmitchell: if you only want to allow integers: ##(Integer/parseInt "1")
17:30	sexpbot	⟹ 1
17:42	mreynolds	I'm blanking on how to force a string to not be treated as a sequence. What's the function to dot hat?
17:43	mec	Is there anything better than (Object.) for a bunch of unique things to use in a map
17:43	mec	as keys* in a map
17:43	mec	mreynolds: what are you wanting to do with the string?
17:43	mreynolds	mec: Trying to create a sequence of strings, not chars
17:43	raek	mec: keywords with namespace parts could be an option
17:44	mreynolds	mec: Trying to build tests for a simple line parser
17:45	mec	mreynolds: so you want to split a string into smaller strings?
17:45	raek	mreynolds: could you show us the code where the problem occurs?
17:46	mreynolds	mec: Actually, I have test strings that I want to feed into a function that then splits them. I have the splitting part, but I want to build a test and that requires building up some test strings.
17:46	raek	mreynolds: there's nothing with strings that keep them from being part of sequences
17:46	mreynolds	raek: k, lemme see what I can do
17:49	mec	raek: I can't know how many ahead of time so I dont think I want to make keywords on the fly
17:51	raek	mec: then (Object.) sounds like a good fit to me
17:51	clojurebot	Excuse me?
17:51	raek	O_ô
17:52	amalloy	mec: (Object.) and (gensym) are the classics
17:52	mec	ah forget about (gensym), I think it would have more overhead tho
17:53	dnolen	gensym is actually quite slow.
17:53	mreynolds	raek: I think I'm running into a problem with printing at the console, not with sequences. One sec.
17:55	amalloy	(Object.) is surely "cheaper"
17:55	mec	I was just using numbers, but I figured eventually I would run out so I'd rather future proof :x
17:56	amalloy	but i bet if you want to debug it's easier to read ##(gensym) than ##(Object.)
17:56	sexpbot	(gensym) ⟹ G__37171
17:56	sexpbot	(Object.) ⟹ #<Object java.lang.Object@1bc2314>
17:57	mec	hmm, maybe a helper function that switches to (gensym) for debugging
17:58	mreynolds	raek: http://pastebin.com/tRb8z2Es
18:03	Ramblurr	is it possible to supress warnings when (use ..) ing?
18:03	raek	mreynolds: some comments: replace (String. "foo") with "foo" and == with =
18:04	mreynolds	raek: Yeah, I did for the affected test (realized the String. was irrelevant), and I had it as "=" before, but I thought == does contents equality?
18:04	raek	Ramblurr: are the warnings caused by your code? if so, you should fix the cause instead... :-)
18:05	Ramblurr	raek: yea they are, i know usually you would want to fix the cause, but in this case my goal is to make the code as small as possible
18:05	raek	mreynolds: == is a rare special operations for numbers. = does what you want
18:05	Ramblurr	raek: so replacing a function is better than using a namespace
18:05	raek	Ramblurr: what var is being replaced?
18:05	mreynolds	raek: k, thanks. Also, found my other bug which is pipe being a special char and I didn't comment it. Commenting it returns the right thing. However, if it fails to split, the function treats the original string as a sequence.
18:06	Ramblurr	raek: im replacing clojure.core/repeat with clojure.contrib.string/repeat
18:06	raek	,(clojure.string/split "\"a\"\|\"b\"\|12345\|12345678901234567890\|\"long string\"\|\"\"\n" #"\\|")
18:06	clojurebot	["\"a\"" "\"b\"" "12345" "12345678901234567890" "\"long string\"" "\"\"\n"]
18:06	raek	mreynolds: I get the string split into its parts
18:06	mreynolds	,(clojure.string/split "\"a\"\|\"b\"\|12345\|12345678901234567890\|\"long string\"\|\"\"\n" #"\|")
18:06	clojurebot	["" "\"" "a" "\"" "\|" "\"" "b" "\"" "\|" "1" ...]
18:07	raek	Ramblurr: and you want to use string's repeat instead?
18:07	mreynolds	mreynolds: That's the bug in my code with pipe.
18:07	Ramblurr	raek: yup
18:07	mreynolds	raek: Trying to remember the interaction of pipe as a regex, and if the original string is being returned as a sequence, or...
18:07	raek	if so, you should have (ns your-ns (:refer-clojure :exclude [repeat]) ...)
18:07	raek	to make that clear
18:08	Ramblurr	raek: doing (use '[clojure.contrib.string :only (repeat)]) and then (repeat..) rather than (require ... :as s/repeat) is less code, but i get a warning :\
18:09	Ramblurr	raek: ah nevermind, the error goes to stderr anyways
18:09	Ramblurr	not stdout, so all is good
18:09	Ramblurr	raek: thanks for that namepsace exclude tip
18:09	raek	for the user namespace in the repl, everything in clojure.core is already referred.
18:10	raek	so it's hard to opt out certains vars in it...
18:11	raek	Ramblurr: :exclude is the correct way to do it. the reason clojure show a warning instead of an error is to not break peoples' projects when new stuff enters clojure.core.
18:12	raek	mreynolds: \| in a regex means alternative, so you have to quote it like \\|, as you did in your paste
18:13	mreynolds	raek: Gotcha, just trying to figure out why the original string gets treated as a sequence in taht case.
18:13	raek	mreynolds: but note that the order of the keys of a map is not maintained, so your equality check will probably fail
18:13	raek	,(clojure.string/split "\"a\"\|\"b\"\|12345\|12345678901234567890\|\"long string\"\|\"\"\n" #"")
18:13	clojurebot	["" "\"" "a" "\"" "\|" "\"" "b" "\"" "\|" "1" ...]
18:14	raek	mreynolds: it doesn't. you split at "nothing"
18:14	mreynolds	raek: Yeah, sorry, building up the test a piece at a time, wanted to jump over the sequence hurdle first
18:14	mreynolds	raek: Gotcha. This is my faulty memory of regex handling in java coming back to bite me
18:14	raek	the string matches nothing, followed by ", followed by nothing, followed by a, etc
18:14	mreynolds	raek: thanks
18:15	raek	one rule about regex literals in clojure is that their syntax is exactly as described in http://download.oracle.com/javase/6/docs/api/java/util/regex/Pattern.html
18:17	mreynolds	raek: Gotcha. I screwed this up when I did java too, so I don't blame clojure for that :)
18:18	mec	when should i use clojure.test/testing vs clojure.test/deftest
18:25	dakrone	mec: use deftest to declare a test, testing to declare sections of a test within a deftest
19:48	mreynolds	'(contains? (list "a" "b" "c") "a")
19:49	mreynolds	,(contains? (list "a" "b" "c") "a")
19:49	clojurebot	false
19:49	mreynolds	Clojuredocs.org has a note on contains? saying they're not sure why that evaluates to false, does anyone here know?
19:50	raek	,(contains? (list "a" "b" "c") 0)
19:50	clojurebot	false
19:50	technomancy	clojurebot: contains?
19:50	clojurebot	contains? is for checking whether a collection has a value for a given key. If you want to find out whether a value exists in a Collection (in linear time!), use clojure.core/some or the java method .contains
19:50	mreynolds	bah
19:50	mreynolds	I'll edit the page :)
19:50	technomancy	contains? is specifically designed to trick newbies into thinking about O(n) characteristics of data structures.
19:50	mreynolds	it worked!
19:51	technomancy	there is no other explanation for why it hasn't been renamed
19:51	technomancy	mreynolds: brilliant. =)
19:54	dnolen	,(associative? '(a b c))
19:54	clojurebot	false
19:54	dnolen	,(associative '[a b c])
19:54	clojurebot	java.lang.Exception: Unable to resolve symbol: associative in this context
19:55	dnolen	,(associative? '[a b c])
19:55	clojurebot	true
19:55	mec	,(contains? '(a b c) 1
19:55	clojurebot	EOF while reading
19:55	mec	,(contains? '(a b c) 1)
19:55	clojurebot	false
19:55	dnolen	,(get '(a b c) 0)
19:55	clojurebot	nil
19:55	dnolen	,(get '[a b c] 0)
19:55	clojurebot	a
19:56	mec	(nth '(a b c) 0)
19:56	mec	,(nth '(a b c) 0)
19:56	clojurebot	a
19:56	dnolen	,(find '(a b c) 0)
19:56	clojurebot	java.lang.ClassCastException: clojure.lang.PersistentList cannot be cast to java.util.Map
19:56	amalloy	i like that explanation, technomancy
19:56	dnolen	,(find '[a b c] 0)
19:56	clojurebot	[0 a]
19:57	amalloy	&(doc find)
19:57	sexpbot	⟹ "([map key]); Returns the map entry for key, or nil if key not present."
19:58	amalloy	neat. i didn't know about that one
20:01	mec	useful if your map's values might be nil
20:01	mec	well i guess thats what not-found is for anyway
20:10	pdk	that sorta thing
20:10	pdk	is why i miss multiple-value-bind sometimes
20:18	mec	is that a language feature or built onto CL?
20:19	amalloy	i think it must be a language feature. pasting it on with other CL primitives would be gross
20:20	mec	you could do it it with with-bindings and 2 macros
20:24	amalloy	i don't think you could do it in a way that is both transparent to non-mvbind contexts and performant. i implemented mvbind in clojure a couple different ways for fun, and they're not very good; i'd be interested to see the way you do it
20:24	mec	sure, working on it now
20:27	mec	what are the 2, mutiple-value-bind and values?
20:38	mec	whats the difference between binding and with-bindings and how do you use either
20:42	mec	https://gist.github.com/949291
20:42	mec	^^ multiple-value-bind
20:53	amalloy	mec: with-bindings is lower-level. wants vars instead of symbols
20:54	mec	well its about 12 times slower than directly using let
20:54	amalloy	mec: i'm not convinced by your solution. it doesn't work to have (values (some-other-mv-function) true), because some-other-mv-function will see the global value of multi-value
20:55	amalloy	ie, you only support one multi-valued function globally at a time - they don't nest
20:55	mec	ah hmm
20:55	amalloy	very neat prototype though. not a way i'd considered doing it
20:57	mec	no idea how to fix that
20:58	mec	other than to wrap ~vals in (binding [multi-value false] ~vals)
21:08	chrissbx	What's the best way to fold over a sequence two elements per step? Like for example the vector with the variables+expressions in a let form.
21:09	mec	any idea why this would throw a null pointer? (when (sequential? x) (= (seq x) (seq this)))
21:09	mec	chrissbx: (partition 2 coll)
21:10	mec	so (reduce (fn [[k v]] ...) (partition 2 coll))
21:14	chrissbx	Thanks. Any way to get error checking for (partition 2 '(k1 v1 k2)) ?
21:14	chrissbx	(Without me doing length calculations around it?)
21:14	mec	(let [kvs (partition 2 coll)] (if (odd? (count kvs)) (throw ...)))
21:15	mec	oh
21:16	chrissbx	well, whatever. I guess I'm just supposed to do it that way.
21:16	mec	(reduce (fn [[k v :as t]] (if (= (count t) 1) (throw Exception.) ...) (partition 2 coll))
21:16	mec	s/partition/partition-all/
21:16	sexpbot	<mec> (reduce (fn [[k v :as t]] (if (= (count t) 1) (throw Exception.) ...) (partition-all 2 coll))
21:17	chrissbx	I always prefer solutions that I can use without caring about errors and that then don't just suppress them.
21:17	chrissbx	But since clojure even doesn't think (first '()) is an error, then I guess my code will never be fool proof anyway.
21:18	chrissbx	I suppose I better get over it.
21:19	mec	its pretty handy that a lot of stuff returns nil instead of exceptions
21:20	chrissbx	Well, at the cost of missing (early) error checking.
21:21	chrissbx	(But partition doesn't even return nil, it just returns part of the solution.)
21:22	mec	ya partition truncates, gotta use partition-all if you want partials
21:23	amalloy	mec: actually i think that's a sufficient fix. wrapping values, that is
21:23	amalloy	clojurebot: partition?
21:23	clojurebot	partition is probably not what you want; see partition-all.
21:23	mec	lol
21:24	amalloy	chrissbx: forget about (first ()), clojure is perfectly happy with ##(first (first (rest (first nil))))
21:24	sexpbot	⟹ nil
21:24	chrissbx	Well, using partition-all will just sweep the error under the carpet in the subsequent reduce.
21:24	amalloy	&(doc partition)
21:24	sexpbot	⟹ "([n coll] [n step coll] [n step pad coll]); Returns a lazy sequence of lists of n items each, at offsets step apart. If step is not supplied, defaults to n, i.e. the partitions do not overlap. If a pad collection is supplied, use its elements as necessary to complet... http://gist.github.com/949317
21:25	mec	ok i changed equiv on this deftype to (equiv [this x]) and it still throws a null pointer when called
21:25	amalloy	chrissbx: pass a "pad" collection that's something like (repeatedly #(throw (Exception. "OMG WUT")))
21:25	amalloy	&(partition 2 2 (repeatedly #(throw (Exception. "OMG WUT"))) (range 4))
21:25	sexpbot	⟹ ((0 1) (2 3))
21:25	amalloy	&(partition 2 2 (repeatedly #(throw (Exception. "OMG WUT"))) (range 5))
21:25	sexpbot	java.lang.Exception: OMG WUT
21:26	mec	wow thats interesting
21:26	amalloy	that still delays the exception until the first wrong-sized partition, but you can't do any better than that and still be lazy
21:27	mec	why does partition do that instead of just passing the function
21:27	amalloy	mec: ?
21:27	mec	ah nvm
21:33	amalloy	chrissbx: anyway you can (defn die [] (repeatedly #(throw...))), and then use (die) as your pad collection
21:33	amalloy	to let you fail as fast as is possible
21:33	chrissbx	well, (def die (repeatedly ...))
21:34	chrissbx	But since I'm used not to bother about edge cases when writing my code, I'll forget about this.
21:34	amalloy	chrissbx: i considered that, i don't think it's a good idea
21:34	chrissbx	And my code will just do unsensible stuff as a consequence.
21:34	chrissbx	And I don't care right now :)
21:35	amalloy	if you use the same lazy-sequence of exceptions and someone ever catches one of them, that first result gets cached and probably would result in silent failures
21:35	chrissbx	What would be cached isntead of the exception?
21:36	chrissbx	ah the result of the exn handler, you mean?
21:36	amalloy	i'm not sure, really. it's a weird case
21:36	chrissbx	heh
21:36	mec	mine keeps blowing up
21:36	chrissbx	mec: amalloy means when you use an exception handler that replaces the exn with a value
21:37	amalloy	yeah, but i was wrong
21:37	amalloy	there's no way it could get cached
21:37	chrissbx	If that's possible in Clojure to have such a handler at all.
21:39	amalloy	no, it's not
21:39	amalloy	the stack unwinds up to the first handler it can find, and grows anew from there
21:41	chrissbx	How do debuggers work, though, if an exception happens? They'll have to capture it with the stack before unwinding.
21:41	amalloy	they attach to the process externally
21:41	chrissbx	(Or have access to the unwound stack after-the fact.)
21:42	chrissbx	(To the un-unwound, I meant)
21:42	amalloy	and then the jvm gives them priority execution while the target program is suspended
21:42	chrissbx	k
21:43	chrissbx	Maybe that'll be a feature in a future Clojure version (for restarts ...).
21:44	chrissbx	Then my code will break then :)
21:45	chrissbx	My future is already doomed while learning Clojure.
21:45	amalloy	eh?
21:49	chrissbx	Just exaggerating.
22:26	semperos	informational question: what do folks think would be interesting metrics to "calculate" from scanning all of Clojure's IRC logs for the last three years?
22:34	mec	semperos: number of unique visitors could be interesting
22:35	semperos	mec: thanks
22:35	semperos	any thoughts on "equivalent" nicks? by default i was thinking "foo" and "foo_" with any number of underscores
22:36	mec	also ` and preceding _
22:37	semperos	` at the end?
22:37	semperos	I've been brainstorming a few things, esp. around clojurebot/sexpbot use, specific Clojure fn's, folks who talk the most, folks "on" most number of days
22:37	semperos	things in that vein
22:48	chrissbx	semperos: you might catch most nick duplicates by checking for renames
22:48	semperos	true
22:49	semperos	actually using the logs saved at n01se.net for this, where those aren't captured
22:49	chrissbx	ah
22:49	semperos	but a fine thought
22:51	semperos	here's what I have so far after a quick brainstorm:
22:51	semperos	* Total unique visitors
22:51	semperos	* Total messages
22:51	semperos	* Total mentions of particular languages (Java, Ruby, Lisp)
22:51	semperos	* Clojurebot vs Sexpbot use
22:51	semperos	* For a user, total messages
22:51	semperos	* For a user, total days "online" (at least one message)
22:51	semperos	* Top users
22:51	semperos	* Top days (number of messages)
22:51	semperos	* Top Clojure fn's mentioned/used
22:51	semperos	was hoping that wouldn't make separate messages...
22:52	semperos	obviously there'll be ambiguity, but this is a start
22:53	semperos	* For a user, number of messages including Java interop forms
22:59	chrissbx	Another fine thought might be to ask for the source files used by n01se.net, esp. since there seems to be a parser for those at https://github.com/Chouser/clojure-irc-log