#clojure – 2014-10-05

2014-10-05

00:02	dbasch	amalloy: still, with an array long-to-hash only becomes 10% faster
00:07	dbasch	amalloy: actually it becomes significantly faster, encode overall still takes 4x as long as the java version
00:07	amalloy	sure, but you're getting there
00:07	amalloy	you should be able to get it to at most 1.5x
00:08	amalloy	if you're inclined to keep pushing
00:11	dbasch	amalloy: well, I could rewrite the entire thing in java from clojure :)
00:12	dbasch	the initial question was, what was the point of writing a clojure implementation of something for which there is a very performant java library
00:26	alexyz	is there a way to get from a Java array to a Clojure seq?
00:31	dbasch	alexyz: (seq the-array)
00:34	dbasch	btw, if you change the-array, the seq changes so don’t do it
00:35	dbasch	(the sequence is backed by the array directly)
00:36	alexyz	dbasch thanks
00:37	alexyz	meanwhile I have found a "native" Clojure function so no need to convert
00:38	alexyz	still reading about multimethods... if the dispatch function returns a sequence how should I define a defmethod? I've tried '("text" "html") and it doesn't seem to match --- everything going to :default
00:39	alexyz	http://pastie.org/9621536
00:51	dbasch	alexyz: why do you need a multimethod there? it seems like you just want a case
00:52	amalloy	alexyz: multimethods are sneaky buggers, greatly opposed to being redefined. i bet if you (def my-multi nil) and then re-run that code it works fine
00:53	dbasch	I still think that’s an unnecessary usage of a multimethod though
00:54	alexyz	dbasch I asked earlier and was told about multimethod which seems to fit pretty well. I didn't know about case though
00:55	alexyz	amalloy unfortunately I'm not following you. I have found a bug in that code though and now it seems to work fine
00:56	dbasch	or not even a case, a map would do just fine
00:57	alexyz	dbasch in what sense a map?
00:57	dbasch	alexyz: you have a mapping of mime types to titles, right?
00:58	alexyz	dbasch nope... for each mime type I plan to apply a different approach for finding out the real title
00:58	alexyz	so basically it's a mapping from mime types to functions
00:58	dbasch	alexyz: ok, in that case a case
00:58	alexyz	that's why multimethods sounded like exactly what I needed
00:59	dbasch	multimethods are more useful when you have things of different types, and you don’t want to be figuring out what something is
00:59	dbasch	but in your case you always have two strings
01:00	alexyz	but the processing is rather different... and this sounds a lot like polymorphism
01:01	alexyz	I mean I'm pretty sure I can achieve the same results with either multimethods or a case so the real question here is more about what's the idiomatic way
01:01	dbasch	alexyz: in this situation it’s a matter of taste I guess. If you like it that way, why not
01:01	alexyz	I'll actually give it a try to both to learn how each of them feels
01:03	dbasch	I guess the other reason for multimethods is when you don’t know all your cases in advance and you want to be able to add dispatch methods without touching the existing logic
01:04	alexyz	dbasch in this particular case I thought that having the :default matcher around could prove quite useful
01:05	dbasch	alexyz: see also cond
02:13	sineer	Anyone knows how to use use .appendChild with Om dom/div ?
03:03	borkdude	bbloom what's the difference between union and sum types?
03:05	julienmarie	Hello all. I'm quite of a newbie here. I got troubles to swap! a nested atom. I feel a bit lost about it for now ( first week on clojure / clojurescript ) http://pastebin.com/bwSqBLxW .Been scratching my head for a day on that now…
03:16	borkdude	julienmarie I suggest you add a println to set-active to see what you are calling it with
03:16	julienmarie	@borkdude I'll do that
03:19	julienmarie	@borkdude this is what I'm getting [:menu [{:name Dashboard, :path /, :icon dashboard} {:name Analytics, :path /analytics, :icon analytics}]]
03:19	julienmarie	but I need to iterate under the :menu symbol
03:19	borkdude	julienmarie I suggest you now look at the update-in function
03:20	julienmarie	instead of assoc ?
03:20	borkdude	julienmarie or assoc-in
03:20	borkdude	just take a look at those functions
03:23	julienmarie	@borkdude thanks!
03:24	borkdude	np
03:31	borkdude	question about core.typed: when I define a function in namespace a and also have the annotation there, and this function is called from namespace b incorrectly typewise, lein typecheck a b doesn't find it
03:31	borkdude	question is: what am I doing wrong
03:34	borkdude	cfleming renaming via filename refactors namespaces name, but not the other way around
03:37	borkdude	hmm, lein typed says: "Not checking ringapp.other (tagged :collect-only in ns metadata)"
03:37	borkdude	while I called it with lein typed ringapp.api ringapp.other
04:14	H4ns	i'm using http-kit+ring+compojure and my static resources are not found. i've looked at the system class loader (java.lang.ClassLoader/getSystemClassLoader) path and found that it contains the right directories. it seems, though, that a different class loader is used.
04:14	H4ns	any ideas how i could debug this further?
04:16	H4ns	in fact, the context class loader path seems to not contain anything
04:23	H4ns	apparently, a restart of my application helped with this.
05:14	cfleming	borkdude: Yeah, there's a few cases I need to fix there - the namespace code is old and crufty unfortunately
05:15	cfleming	borkdude: How's the core.typed support in Cursive BTW? It's pretty new and I haven't used it in anger yet.
05:15	cfleming	borkdude: I'd like to start using core.typed for some of the Cursive code but I haven't yet.
05:54	SagiCZ1	is there any way to take a string and compile it as a C code in java?
05:55	martinklepsch	I just wrote a bit of code that feels complicated, would be happy if someone could take a look: https://gist.github.com/mklappstuhl/60b061d749f0c0c12275
05:59	dysfun	Hi. what interface do i have to implement to support conj?
06:00	SagiCZ1	dysfun: Sequential?
06:00	dysfun	tuy
06:36	dysfun	is there a nice clojurescript dom library that might work under clojure with a webkit open?
06:37	dysfun	the api is basically the same
06:42	dysfun	dommy looks interesting. i'm not sure if i approve or disapprove of the gross abuse of macros in that way
06:48	mbac	how do i make a plot of a sequence of [x y] appear on my screen with minimum effort
06:48	mbac	(clojure.magic/plot data) isn't working :P
06:49	mbac	is it loom?
06:50	borkdude	cfleming I have the following issue with core.typed in general now: https://www.refheap.com/91197
06:50	borkdude	cfleming it's not entirely clear what happens when you just check 1 ns... what happens if the annotations are in another namespace? or when annotations are in "this" namespace, but calls in another?
06:51	cfleming	borkdude: Hmm, interesting - I'm not sure, I must admit. I implemented the Cursive support modelling it on the calls that the Emacs/Vim support makes, but like I say I still haven't used it myself other than to test it.
06:52	cfleming	borkdude: So I'm still not sure about a lot of the core.typed details.
06:52	borkdude	cfleming me neither. I started using it because it was present in the REPL menu :)
06:52	cfleming	borkdude: Haha - so you'll try all the libraries I add support for?
06:52	borkdude	cfleming maybe
06:53	borkdude	cfleming if I get a free license :P
06:53	cfleming	borkdude: I'll run it by my CFO
06:54	borkdude	cfleming how big is your team/company?
06:54	borkdude	cfleming I thought you were the only one
06:54	cfleming	borkdude: It's just me.
06:54	borkdude	hehe ok
06:54	cfleming	borkdude: My CFO is either me, or my wife
06:54	borkdude	cfleming lol ok.
06:57	borkdude	cfleming I actually had a use case for core.type to find possible null pointers in some code which uses bigints extensively, but until I can work this namespace problem out, it won't be of much use
06:57	borkdude	cfleming it's more a core.typed thing than cursive
06:57	cfleming	borkdude: Try the core.typed mailing list, ambrosebs is very responsive on there
06:57	cfleming	borkdude: When he's not around here, that is.
06:58	borkdude	cfleming I already pinged him on twitter, so I think he'll respond soon
06:58	cfleming	borkdude: Ok cool
07:00	cfleming	borkdude: Speaking of null pointers, check this out: http://t.co/qTbnjiXwpg
07:01	borkdude	cfleming yeah, I saw it via your twitter
07:01	cfleming	borkdude: I have a total geek crush on jetbrains
07:02	dysfun	that is pretty cool
07:02	dysfun	shame i hate IDEs
07:02	cfleming	dysfun: That is a shame :-)
07:03	borkdude	cfleming do I understand correctly you would have to add annotations in order for it to detect possible NPEs?
07:03	borkdude	it's still cool though
07:04	cfleming	borkdude: No, they've had that for ages. This infers what and where the annotations should be.
07:04	cfleming	borkdude: Depending on how well it works, it might completely eliminate NPEs in Java
07:06	borkdude	cfleming so you have a program in java with possible NPEs, intellij warns that you should add annotations?
07:09	mbac	oh wait maybe it's incanter
07:09	borkdude	cfleming "infer annotations" means you wouldn't have to add them, so why speak of annotations - isn't that more of an implementation detail?
07:09	mbac	wait maybe i should just write text to a file and use gnuplot
07:11	cfleming	borkdude: Right, that's a little confusing, I think they're talking about what their algorithm actually infers. As I understand it it'll infer what those annotations should be in SDK/library code.
07:11	cfleming	borkdude: I'm assuming it can also tell you where they should go in your own code.
07:12	cfleming	borkdude: I'm guessing this analysis is independent of the actual NPE checking
07:13	cfleming	borkdude: But if it can use the inferred ones, you're right, the annotations themselves become a little redundant except as documentation.
07:21	mbac	i find myself doing (map (fn [i x] [i x]) (range (count xs)) xs) a lot
07:21	mbac	is there something more idiomatic
07:21	Bronsa	,(map-indexed vector '[a b c])
07:22	clojurebot	([0 a] [1 b] [2 c])
07:22	Bronsa	mbac: ^
07:23	mbac	thank you!
08:03	clj-learner	whats the difference between (resolve 'first) and #'first
08:18	dysfun	oh excellent, i made java segfault
08:21	rweir	gold star!
08:21	rweir	unless it involved JNI
08:25	dysfun	well, only JNI written by oracle
08:25	dysfun	(javafx)
08:25	rweir	silver star then ;p
08:25	dysfun	javafx is certainly interesting
08:26	dysfun	i had no idea an api could be made this infuriating
08:26	rweir	worse than jdbc?
08:26	dysfun	but i think being able to crash a browser by loading a webpage with a simple javascript loop is quite special
08:44	gfredericks	,`````````x
08:44	clojurebot	#<StackOverflowError java.lang.StackOverflowError>
09:36	hyPiRion	oh, you.
09:46	noncom	how do i in clojure better find the constructor for a class that I need and pass the required parameters to it? i cannot make (.getConstructors) with (.newInstance) to work with it..
09:51	gfredericks	noncom: you're asking about how to find documentation on java classes, or just call a constructor, or something else?
09:51	gfredericks	,(BigInteger. "42") ;; calling a constructor
09:51	clojurebot	42
09:53	gfredericks	,(.newInstance BigInteger "42")
09:53	clojurebot	#<IllegalArgumentException java.lang.IllegalArgumentException: No matching method found: newInstance for class java.lang.Class>
09:53	justin_smith	dysfun: SagiCZ1: hash-maps and sets support conj but are not sequential
09:53	gfredericks	,(.newInstance BigInteger)
09:53	clojurebot	#<InstantiationException java.lang.InstantiationException: java.math.BigInteger>
09:53	dysfun	sigh i wonder what we could achieve with something similar to html but with an immutable DOM
09:55	gfredericks	noncom: the docs for newInstance state that it won't work if the class doesn't have a zero-arg constructor
10:09	rubberduck	anyone familiar with core.async.impl.protocols ? in particular what's the procedure for implementing ReadPort in clojure ?
10:09	rubberduck	from what I can tell you get passed a handler and you must lock it then check if it's active and call commit with the value
10:10	rubberduck	ManyToManyChannel implementation isn't very straightforward :(
10:12	kungi	Can I somehow create a globally unique symbol?
10:13	justin_smith	,(symbol (java.util.UUID/randomUUID))
10:13	clojurebot	#<ClassCastException java.lang.ClassCastException: java.util.UUID cannot be cast to java.lang.String>
10:13	justin_smith	err
10:13	justin_smith	,(symbol (str (java.util.UUID/randomUUID)))
10:13	clojurebot	906eafe8-36c2-4cb7-b035-65d39983413c
10:13	kungi	justin_smith: Hmm ok this is possible.
10:14	justin_smith	globally unique (or at least pretty damned close to it)
10:14	kungi	justin_smith: thanks
10:21	noncom	gfrederics: say i have a class with 2 constructors - 1) parameterless, 2) with some params. i want to be able to call the parametrized one, passing the parans
10:22	noncom	gfredericks: sorry, misspelled the nick :)
10:25	noncom	gfredericks: actually, my ultimate goal is to be able to find a class by its name, so that i use (Class/forName) and then call a parametrized constructor on it to get the instance... what would be the best approach for that ?
10:26	gfredericks	,(.getConstructors BigInteger)
10:26	clojurebot	#<Constructor[] [Ljava.lang.reflect.Constructor;@1b91ad7>
10:26	noncom	,(.getConstructors (Class/forName "BigInteger"))
10:26	clojurebot	#<ClassNotFoundException java.lang.ClassNotFoundException: BigInteger>
10:27	gfredericks	,(map #(seq (.getParamaterTypes %)) (.getConstructors BigInteger))
10:27	clojurebot	#<IllegalArgumentException java.lang.IllegalArgumentException: No matching field found: getParamaterTypes for class java.lang.reflect.Constructor>
10:27	gfredericks	,(map #(seq (.getParameterTypes %)) (.getConstructors BigInteger))
10:27	clojurebot	(([B) (int [B) (java.lang.String int) (java.lang.String) (int java.util.Random) ...)
10:27	noncom	hmmm... thats giving some signatures !
10:27	gfredericks	,(def my-string-constructor (->> BigInteger (.getConstructors) (filter #(= [String] (seq (.getParameterTypes %)))) (first)))
10:27	clojurebot	#'sandbox/my-string-constructor
10:28	gfredericks	,(.newInstance my-string-constructor (into-array ["42"])
10:28	clojurebot	#<RuntimeException java.lang.RuntimeException: EOF while reading>
10:28	gfredericks	,(.newInstance my-string-constructor (into-array ["42"]))
10:28	clojurebot	42
10:28	gfredericks	so that does it I think
10:28	gfredericks	you might also find a helper in the clojure.lang.Reflector class
10:28	gfredericks	or something to that effect
10:29	gfredericks	noncom: https://github.com/clojure/clojure/blob/master/src/jvm/clojure/lang/Reflector.java#L150
10:29	gfredericks	,(clojure.lang.Reflector/invokeConstructor BigInteger (into-array ["42"]))
10:29	clojurebot	42
10:29	gfredericks	rather easier
10:32	noncom	gfredericks: wow!
10:32	noncom	gfredericks: that's it, thanks! :)
10:32	gfredericks	np
11:49	john________	Can ask a datomic question here?
11:50	AeroNotix_	john________: don't ask to ask, ask.
11:52	john________	I hope it is not unpolite to paste in serveral lines of a datomic query code:
11:52	john________	[:find ?e ?name
11:52	john________	:where
11:52	john________	[?e :item/name ?name]
11:52	john________	[?e :item/values ?ref]
11:52	justin_smith	use a pastebin
11:52	john________	[?ref :value/attribute ?a]
11:52	john________	[?a :attribute/ident “12009”]
11:52	john________	]
11:52	justin_smith	use refheap.com next time
11:52	john________	allright thanxs I do that from now on!
11:53	justin_smith	I'm guessing you are fairly new to IRC
11:54	john________	yes! quite just used it so far only a couple of times for short questions
11:54	john________	https://www.refheap.com/91206
11:55	justin_smith	thanks
12:04	bbloom	borkdude: i explained it to gfredericks
12:14	viktar	(+ 2 2)
12:14	clojurebot	4
12:15	mbac	so, it's kind of a drag that for toplevel scopes you need to use def but inside of defs you need to use let
12:17	gfredericks	mbac: they're pretty different
12:19	gfredericks	it's not just about positioning
12:20	mbac	what's different about them?
12:20	mbac	or, rather, why would you want them to be different?
12:20	gfredericks	def is for things that can be referenced from anywhere, and they are also mutable (e.g., for code reloading)
12:20	AeroNotix_	mbac: let is scoped
12:20	gfredericks	so there's more indirection involved
12:20	mbac	can't you just think of the top-level scope as the body of function that wraps the module
12:21	AeroNotix_	mbac: def can be accessed from outside the namespace it's being defined as well
12:21	gfredericks	mbac: that kind of hand-waves around how code reloading works
12:21	mbac	oh. hmm.
12:21	justin_smith	mbac: you can't, because the body of a function is immutable, and global bindings are not
12:22	mbac	wait so (def x 0) (def y (based-on x)) (def x 1) is a thing?
12:23	justin_smith	it's terrible, but it's a thing
12:23	mbac	:'(
12:23	mbac	i guess that's super useful sometimes...
12:24	justin_smith	mostly for development workflows, but yeah, I get pretty damn suspicious when I see it being done in code
12:26	borkdude	bbloom I'll have to dig up the logs then
12:29	justin_smith	,(name "name")
12:29	clojurebot	"name"
12:30	justin_smith	it's handy, but it surprised me
12:32	bbloom	yeah, especially because ##(keyword :keyword) doesn't work, nor does ##(symbol 'symbol)
12:32	lazybot	(keyword :keyword) ⇒ :keyword
12:32	lazybot	(symbol (quote symbol)) ⇒ symbol
12:32	bbloom	oh wow, maybe it does
12:32	bbloom	nevermind
12:33	bbloom	&clojure-version
12:33	lazybot	⇒ {:major 1, :minor 4, :incremental 0, :qualifier nil}
12:33	bbloom	huh
12:35	justin_smith	,(keyword :keyword)
12:35	clojurebot	:keyword
12:35	justin_smith	,(symbol 'symbol)
12:35	clojurebot	symbol
12:36	justin_smith	yeah, these facts just simplified some of my code immensely
12:36	bbloom	justin_smith: oh, i remember now:
12:36	bbloom	,(symbol 'namespace 'name)
12:36	clojurebot	#<ClassCastException java.lang.ClassCastException: clojure.lang.Symbol cannot be cast to java.lang.String>
12:36	bbloom	yeah
12:36	bbloom	:-/
12:36	justin_smith	ahh
12:36	bbloom	,(keyword 'ns 'n)
12:36	clojurebot	#<ClassCastException java.lang.ClassCastException: clojure.lang.Symbol cannot be cast to java.lang.String>
12:36	bbloom	,(keyword 'ns "n")
12:36	clojurebot	#<ClassCastException java.lang.ClassCastException: clojure.lang.Symbol cannot be cast to java.lang.String>
12:36	bbloom	no good
12:37	justin_smith	luckily I don't need that version for my code
12:47	bbloom	hmm so core.async gos get GC-ed if they are waiting on channels for which nobody holds the other end... but what about threads created with clojure.core.async/thread ?
12:47	dysfun	is there anywhere i can read about things planned for future versions of clojure?
12:48	bbloom	dysfun: http://dev.clojure.org/display/design/Home
12:48	dysfun	thanks
12:56	allenj12	how does this work if conj never gets a coll? (def foo [x] (when (> x 0) (conj (foo (dec x)) x))) => (foo 5) -> (5 4 3 2 1)
12:57	gfredericks	,(defn foo [x] (when (> x 0) (conj (foo (dec x)) x)))
12:57	clojurebot	#'sandbox/foo
12:57	gfredericks	,(foo 5)
12:57	clojurebot	(5 4 3 2 1)
12:58	gfredericks	,(conj nil 1)
12:58	clojurebot	(1)
12:58	gfredericks	allenj12: ^^ nil is treated as an empty collection sometimes
12:59	allenj12	gfredericks: why do i feel like thats a bad thing?
12:59	allenj12	kinda goes against the philosophy nothing is nothing, an empty list is something
12:59	bbloom	allenj12: industry wide brainwashing?
13:00	bbloom	i kid though, i go back and forth on my feelings about nil :-P
13:00	dysfun	because you'd like it to not error out and a lot of things that return sequences may also return nil
13:00	allenj12	eh i have mixed feelings about this aswell
13:01	bbloom	in general, clojure handles nil reasonably sanely
13:02	justin_smith	allenj12: things silently returning nil are pretty pervasive in clojure
13:02	justin_smith	,(+ nil)
13:02	clojurebot	nil
13:02	justin_smith	,(+ :a)
13:02	clojurebot	#<ClassCastException java.lang.ClassCastException: Cannot cast clojure.lang.Keyword to java.lang.Number>
13:03	bbloom	justin_smith: (+ nil) is just garbage in garbage out
13:03	bbloom	+ is defined for numbers only
13:03	allenj12	huh
13:03	justin_smith	sure, but notice that it catches it with :keword
13:03	justin_smith	but not with nil, that was my point
13:04	bbloom	justin_smith: that's b/c nil can be a Number
13:04	justin_smith	sure, the pervasiveness of nils is related to the underlying jvm
13:04	justin_smith	not accusing clojure here, just describing
13:04	allenj12	i see
13:06	bbloom	yeah, that's a good point: null is pervasive on the jvm already, so shouldn't fight it
13:07	justin_smith	for comparison, we can look at how scala handels it http://blog.sanaulla.info/2009/07/12/nothingness/
13:07	justin_smith	which to me reads like a language designed by Heidegger or something
13:09	aaelony	justin_smith: (and "being" t
13:09	aaelony	justin_smith: (and "being" "time")
13:10	justin_smith	hehe
13:10	aaelony	hehe ;)
13:17	justin_smith	john_______: did you ever get any help with your datomic question
13:18	justin_smith	or, more to the point, did you ever actually ask it?
13:19	john_______	@justin_smith: yes but nobody answered. I asked why this query https://www.refheap.com/91206 performs so bad. I also posted a question to the datomic user group
13:20	john_______	but as always I think I just have to read and learn more about how datomic handles queries
13:46	dpathakj	,(and “being” “time”)
13:46	clojurebot	#<CompilerException java.lang.RuntimeException: Unable to resolve symbol: “being” in this context, compiling:(NO_SOURCE_PATH:0:0)>
13:46	justin_smith	dpathakj: inc clojure, smart-quotes aren't quotes
13:46	justin_smith	,(and "being" "time")
13:46	clojurebot	"time"
13:47	dpathakj	Yeah. Looks like I just found out that my irc client is smart-quoting on me.
13:47	justin_smith	*in clojure
13:47	borkdude	cfleming namespaces that don't require core.typed won't be type checked
13:47	borkdude	cfleming sais ambrose
13:48	john_______	justin_smith Somebody helped me on the datomic IRC thanxs alot
13:49	justin_smith	borkdude: I can see how that would be useful actually.
13:49	borkdude	justin_smith tell me
13:50	viktar	exit
13:50	justin_smith	borkdude: if I am adapting a codebase to use core.typed, that means I can work throught it one ns at a time.
13:51	borkdude	justin_smith then what is the point of calling lein typed with specific namespaces
13:51	justin_smith	borkdude: and if I have a feature that turns into a terrible rabbit hole when I try to strictly type it, I can still typecheck all the other namespaces, even if that one would never survive the check.
13:51	justin_smith	borkdude: sorry, I know nothing about "lein typed"
14:23	michaelr524	hey
14:24	pellis	hi all
14:24	pellis	is this the proper place for clojurescript q's?
14:24	michaelr524	here is an excersize, how would you split a constant length string to 5 parts of a given length
14:24	michaelr524	pellis: yeah, why not
14:25	pellis	well i just tried deep diving into om and clojurescript
14:25	pellis	given around 1 month experience with clojure (but i do learn fast)
14:25	pellis	my last clojure code was around a year ago
14:26	michaelr524	[8, 4, 4, 4, 12] <- these lengths
14:26	pellis	i came to the conclusion that i can't really do something complex - I need some background in clojurescript first.
14:26	pellis	so my question is - what would be a good place to slowly introduce clojurescript into existing javascript projects?
14:26	pellis	is that even wise?
14:27	pellis	for example - a clojurescript coffeescript hybrid ? or clojurescript on node.js?
14:28	michaelr524	pellis: i think the best way to start would be to build a clojurescript only project
14:28	justin_smith	,,(reduce (fn [[acc s] n] [(conj acc (subs s 0 n)) (subs s n)]) [[] "this is the input string, is it long enough?"] [8 4 4 4 12])
14:28	michaelr524	pellis: why mix in javascript?
14:28	clojurebot	[["this is " "the " "inpu" "t st" "ring, is it "] "long enough?"]
14:28	justin_smith	michaelr524: see above
14:28	pellis	michaelr524: what if i feel too insecure there? should i go back to square one and invest time in learning first?
14:28	michaelr524	justin_smith: one sec, let me parse that
14:28	justin_smith	exercise for the reader: error checking for when the string runs out
14:29	michaelr524	pellis: just build one simple project in clojurescript - this should cure your problems :)
14:29	pellis	michaelr524: i can't build anything simple enough :(
14:32	michaelr524	pellis: why not?
14:33	michaelr524	justin_smith: cool, i like your solution
14:33	justin_smith	thanks
14:33	pellis	michaelr524: i guess i can't think simple enough. i've been doing complex problems for too long, that i consider everything trivial
14:33	justin_smith	it errors out if the input string is too short
14:33	michaelr524	justin_smith: i was thinking in the same direction actually.. but maybe there is a way to make it more efficient?
14:33	michaelr524	i wonder
14:34	justin_smith	more efficient? yeah, use a transient
14:34	michaelr524	justin_smith: the string will always be the same size. it's an rfc compliant uuid without the '-'s
14:34	justin_smith	error checking? maybe assert that the length of the string is longer than the sum of all the sizes, and if not, bail
14:34	michaelr524	justin_smith: i want to bring the '-' back
14:35	justin_smith	oh, never mind that part then :)
14:36	seangrove	Any way to destructure the last item in a seq?
14:36	michaelr524	justin_smith: it's kinda surprised me actually, i've never seen the acc in (reduce) abused in such a nice way :)
14:37	Bronsa	seangrove: nope
14:37	seangrove	Bronsa: Didn't think so, but thought it might be worth it to ask - thanks
14:40	justin_smith	,(map identity (second (reduce (fn [[index acc s] n] (aset acc index (subs s 0 n)) [(inc index) acc (subs s n)]) [0 (make-array String 5) (str (java.util.UUID/randomUUID))] [9 5 5 5 12])))
14:40	clojurebot	("d1d7a603-" "e9c3-" "4c5a-" "8b27-" "65aef1b44629")
14:41	justin_smith	the map identity is because arrays don't print very readably :)
14:41	Bronsa	seq?
14:41	takemikazuchi	Hi guys, is this a good place to ask some basic questions? I'm a little confused about string equality in Clojure.
14:41	justin_smith	Bronsa: ahh, of course :)
14:41	justin_smith	takemikazuchi: go for it
14:42	hiredman	yes
14:42	takemikazuchi	justin_smith: Thanks. Here's the gist: https://gist.github.com/Takemikazuchi/04d2db23a0d6437296c9
14:42	michaelr524	justin_smith: nice.. but think further about it, i think i'll just maybe go for the crazy stupid solution and concat the result of 5 (subs) :)
14:43	takemikazuchi	I mean this works like I expect: ,(= "E" (clojure.string/capitalize "E"))
14:43	takemikazuchi	But the behavior changes when I'm iterating over a string, I suppose?
14:44	justin_smith	michaelr524: or even construct it directly from 5 calls to subs, since it's always five elements :)
14:44	justin_smith	takemikazuchi: when you iterate on a string you get characters, not strings
14:44	clojurebot	Excuse me?
14:44	hiredman	takemikazuchi: you are comparing characters to strings
14:44	takemikazuchi	Thanks makes sense.
14:45	takemikazuchi	so capitalize is returning a string
14:45	hiredman	I suspect so
14:45	takemikazuchi	Yup that was it!
14:45	justin_smith	,(clojure.string/capitalize \e)
14:45	clojurebot	"E"
14:45	justin_smith	yup
14:46	takemikazuchi	Just needed to add (str x)
14:46	justin_smith	,(first (clojure.string/capitalize \e)) ; second option
14:46	clojurebot	\E
14:47	michaelr524	justin_smith: exactly, that's what I was trying to communicate in my last sentence hehe
14:47	justin_smith	michaelr524: ahh, OK. We have a concat function so it was ambiguous
14:48	justin_smith	though in context concat would not actually make any sense...
14:48	cfleming	borkdude: ok, so for external annotations you'd type check the ns containing the annotations, not the actual code? Makes sense.
14:49	cfleming	borkdude: I should really test that!
14:49	borkdude	cfleming well, that wasn't what I meant. say I have a call in a namespace "other" to function f that is called with the wrong type
14:50	justin_smith	michaelr524: bonus, the version with five calls of subs in a collection will be more readable too
14:50	borkdude	even when I have an annotation in namespace "other2" and typecheck "other2", it won't detect the wrong call in "other" if it didn't require core.typed
14:51	borkdude	cfleming If I would add the require to "other" and type check other, it will detect
14:51	borkdude	cfleming so that's all you have to do I think
14:51	borkdude	cfleming checking "current ns" doesn't work if you haven't got the require, that's what it boils down to
14:53	takemikazuchi	justin_smith, hired_man, thanks guys.
14:54	cfleming	borkdude: But if other doesn't have the require, then it can't be annotated, right?
14:54	takemikazuchi	Got to question 30 of 4Clojure
14:54	borkdude	cfleming the annotation can be in a different namespace
14:56	cfleming	I see. And this restriction is from core.typed itself, right?
14:56	borkdude	cfleming for example, this works with the require, not without: https://www.refheap.com/91211
14:56	borkdude	cfleming yes
14:57	borkdude	cfleming "works" -> "type checks"
14:59	borkdude	cfleming you could add a warning when someone calls "type check current namespace" when the require isn't present
15:00	michaelr524	justin_smith: https://www.refheap.com/91212
15:00	michaelr524	justin_smith: could have used a vector of the calls + join of course
15:01	michaelr524	justin_smith: but maybe this is more efficient :)
15:01	justin_smith	michaelr524: ahh - why not a StringBuilder?
15:01	justin_smith	StringBuilder would be more efficient by far, I didn't realize what you were doing
15:01	michaelr524	justin_smith: well, there is a roumor that java automatically creates a StringBuilder when you try something like that
15:01	rubberduck	anyone here familiar with clojure.core.async.impl.protocols ? I'm having trouble figuring out the required semantics for ReadPort implementation since it's not documented
15:02	rubberduck	and the only implementation (chan) is cluttered with buffer stuff which is hard to follow
15:02	justin_smith	michaelr524: I had no idea, but really using a StringBuilder directly would not be that much more complex
15:02	borkdude	doesn't clojure have transient strings for that? ;P
15:02	michaelr524	justin_smith: I think that's the latest recommendation from the java people, instead of using a StringBuilder just concatenate your strings aways with that + operator
15:03	justin_smith	if java does it (as in the compiler), that doesn't help at all
15:03	justin_smith	clojure does not use the java compiler except when building the clojure jar
15:03	michaelr524	justin_smith: there is a point in what you are saying here
15:03	michaelr524	hmm
15:04	hyPiRion	,(time (do (reduce str "" (range 100000)) nil))
15:04	michaelr524	then probabaly a StringBuilder would be better
15:04	clojurebot	eval service is offline
15:04	hyPiRion	oh, uh
15:04	michaelr524	eval service went out of bussiness
15:04	justin_smith	hyPiRion: but that's not using concat calls
15:04	borkdude	insert coin
15:04	hyPiRion	justin_smith: oh, so it's concat vs. stringbuilder?
15:05	justin_smith	yeah, that's what we are comparing
15:06	hyPiRion	&(let [s (mapv str (range 10000))] (time (do (reduce #(.concat %1 %2) "" s) nil)))
15:06	lazybot	Execution Timed Out!
15:06	hyPiRion	oh whoah, you shouldn't timeout on that
15:07	hyPiRion	lazy bugger
15:07	hyPiRion	&(let [s (mapv str (range 10000))] (time (do (apply str "" s) nil)))
15:07	lazybot	⇒ "Elapsed time: 8.555949 msecs" nil
15:07	hyPiRion	str is using stringbuilder internally
15:07	mbac	(defn save-sexp [d f] (with-open [w (clojure.java.io/writer f)] (.write w (binding [print-dup true] (prn d)))))
15:08	mbac	is that no longer the right way to serialize stuff?
15:09	justin_smith	hyPiRion: oh, cool
15:11	michaelr524	ok then
15:11	michaelr524	I've updated the paste
15:11	michaelr524	https://www.refheap.com/91212
15:11	dbasch	amalloy justin_smith I got that geohash code to be “only” 1.8x as slow as the java version
15:11	justin_smith	dbasch: awesome, what did it take?
15:12	dbasch	turns out bit-flip and bit-test are pretty inefficient
15:12	justin_smith	wow, I had no idea
15:14	dbasch	justin_smith: in my benchmark (bit-flip x n) takes twice as long as (bit-xor x (bit-shift-left 1 n))
15:41	dbasch	justin_smith: plus there was some random sillines, e.g. (+ lo (/ (- hi lo) 2)) instead of (/ 2 (+ hi lo))
15:41	dbasch	silliness
15:43	dbasch	this is what I have so far https://www.refheap.com/91217
15:44	dbasch	it has room for improvement
16:10	arrdem	dbasch: isn't locate [double double double long] -> long?
16:10	arrdem	clojure.lang.IFn$DDDLL exists
16:10	arrdem	could be worth something
16:11	dbasch	I’ll try
16:13	dbasch	not sure if that type hint makes a difference, it seems to get lost in the noise
16:14	arrdem	dbasch: yeah looking at that it should get lost in the noise.
16:14	arrdem	dbasch: hinting the return type would only help if it were called in a tight loop, and it isn't.
16:15	dbasch	as it is it takes about 700ns on my machine, compared to 11us for the original function and 400ns for the java version
16:17	dbasch	the one thing I don’t understand is why bit-flip seems so slow compared to the hand-rolled alternative.
16:18	Bronsa	dbasch: it's not inlined so it always gets compiled to flipBit(Object,Object)
16:19	Bronsa	dbasch: replacing (bit-flip x n) with (clojure.lang.Numbers/flipBit x n) should make it fast
16:20	dbasch	Bronsa: I’ll try that, it would make that code more clear
16:20	dbasch	but that’s the kind of function that should be inlined
16:20	Bronsa	it's unfortunate that not all the stdlib has :inline metadata where it would make a difference
16:20	Bronsa	yeah
16:21	dbasch	(inc Bronsa)
16:21	lazybot	⇒ 53
16:21	Bronsa	I have a ticket that adds :inline metadata to most of the predicate functions in core, but I doubt it's ever going to make it in
16:22	arrdem	story of jira...
16:23	Bronsa	arrdem: not as much as jira as the Rich deciding :inline will no longer be used
16:24	Bronsa	arrdem: Alex told me that :inline is deprecated and will no longer be added to functions in core
16:24	Bronsa	deprecated in favour of compiler macros -- which don't exist yet.
16:24	arrdem	sounds about right
16:25	Bronsa	I really don't understand why we can't leverage :inline and replace it later with those, when they'll actually be a thing
16:25	arrdem	what's the word on those. 1.8 ish? not even seeing anything on google or in the logs for em.
16:26	Bronsa	arrdem: they're in the Release.Next page so maybe they'll make it in for 1.7, but who knows
16:27	Bronsa	arrdem: http://dev.clojure.org/display/design/Inlined+code
16:29	arrdem	Bronsa: hum... could probably do that in like... a week for Oxcart/TEJVM
16:31	Bronsa	I would experiment with them if I saw the need for them, but I fail to see the limitation of :inline. I get that definline sucks because it requires eval, but :inline is fine for me. w/e
16:32	arrdem	:inline/definline is a hack IMO due to lack of a real constant folder/partial evaluation engine. It works, but it's just a hacky implementation of a special case that Rich decided was worth caring about.
16:33	Bronsa	actually if I have to be honest :inline kinda sucks too because it requires metadata to be evaluated at analysis time.
16:34	arrdem	'tbaldridge was ... pursuasive that a partial application engine probably wasn't worthwhile generally but you're right in primitive type cases like this it really can pay off
16:34	arrdem	idk
16:34	arrdem	I was planning on doing one and it didn't happen
16:34	arrdem	down that path lies loop unrolling and inlining heuristics. and madness.
16:36	gfredericks	clojurebote: down that path \|lies\| loop unrolling and inlining heuristics. and madness.
16:37	gfredericks	hwhoops.
16:37	gfredericks	clojurebot: down that path \|lies\| loop unrolling and inlining heuristics. and madness.
16:37	clojurebot	Ok.
16:37	cfleming	Bronsa: don't get me started on definline - I still don't understand why there's so much resistance to supporting/using it
16:37	cfleming	Bronsa: Especially now that there's a fix to the main known problem - many thanks for that!
16:38	Bronsa	cfleming: yeah I really don't get it either
16:39	Bronsa	cfleming: TBH I thought that by fixing that AOT compilation bug clojure/core would reconsider its stance on definline, I was kind of baffled when they didn't change stance on it
16:39	arrdem	Bronsa: hum so CL's DEFINE-COMPILER-MACRO defines/allows a second round of declinable form rewriting before code gen?
16:40	justin_smith	~down that path
16:40	clojurebot	down that path lies loop unrolling and inlining heuristics. and madness.
16:40	cfleming	Bronsa: Yeah, me too. At least I can use it in my own code now though.
16:40	arrdem	justin_smith: good thing I'm already mad then
16:40	Bronsa	arrdem: yeah something like that
16:41	Bronsa	arrdem: in t.a speak, it's just extending the -analyze multimethod for 'function-name
16:41	ustunozgur	hi there, a java interop question: (new (.getClass "test1") "test2") doesn't work. is there a way to achieve something like this without reflection?
16:41	Bronsa	cfleming: so you're using a patched clojure?
16:41	arrdem	Bronsa: ehrm... yeah because this occurs at the form level not at the analyzed AST level
16:42	gfredericks	ustunozgur: your example seems inherently reflective
16:42	Bronsa	arrdem: yep
16:42	arrdem	Bronsa: which actually makes this less powerful because you aren't exporting all the analysis stuff.
16:42	arrdem	Bronsa: you can't look at closed overs and soforth
16:42	ustunozgur	yes, gfredericks (assert (= String (.getClass "Test"))) (new String "test") works though.
16:42	Bronsa	arrdem: uh? you get &env and nobody prevents you from calling analyze on &body
16:42	ustunozgur	maybe because it's a special form.
16:43	Bronsa	arrdem: cljs does something like this already
16:43	ustunozgur	not sure where I would need this though, just tinkering.
16:43	gfredericks	ustunozgur: yeah new is a special form; if you don't have the class name at compile time, it's inherently reflective
16:43	Bronsa	arrdem: https://github.com/clojure/clojurescript/blob/master/src/clj/cljs/core.clj#L260-L276 as an example
16:43	cfleming	Bronsa: Yeah, although I haven't applied that patch yet. I will do as soon as the patch stabilises - I've been running with the patch from http://dev.clojure.org/jira/browse/CLJ-1315 since it came out.
16:43	arrdem	Bronsa: I guess. I'd just lean towards exposing the analyzed AST for user definable transforms because almost anything interesting is gonna try to get tha tinformation anyway.
16:44	ustunozgur	gfredericks: OK, thank you.
16:44	arrdem	cfleming: how's the patched verison of Clojure thing working for you? it's been tempting me for a while now.
16:44	Bronsa	I've done that, it gets old really fast
16:44	Bronsa	commits in clojure master break everything
16:45	gfredericks	what are we patching for?
16:45	cfleming	arrdem: It's working well for me, I'm still running 1.5.1.
16:45	Bronsa	and you're left trying to manually merge everything
16:45	arrdem	gfredericks: rabble rabble rabble
16:45	cfleming	arrdem: Everyone using Cursive is using a patched version.
16:45	Bronsa	cfleming: ssssh they don't need to know
16:45	arrdem	Bronsa: interesting example. thanks.
16:46	gfredericks	ah
16:46	cfleming	Bronsa: Hehe, yes, my lips are sealed.
16:46	arrdem	lol @ ninja patched version
16:46	gfredericks	how do you convince leiningen to use a patched version? do you have to exclude clojure from every dep?
16:46	gfredericks	is there a global exclude feature?
16:46	cfleming	gfredericks: I use Ant. It doesn't take much convincing.
16:46	Bronsa	arrdem: that's a really nice example actually, I've tried moving that transformation to the AST level as a pass, and it's way easier to do it this way
16:46	gfredericks	cfleming: that is the first time anybody has told me that.
16:47	Bronsa	gfredericks: just exclude org.clojure/clojure and include my.clojure/clojure
16:47	gfredericks	Bronsa: so leiningen does have a global exclude?
16:47	arrdem	gfredericks: not that I'm seeing. you have to roll it manually.
16:47	gfredericks	I guess a plugin could do the dirty work
16:47	arrdem	this is actually the primary reason why I've never used org.oxlang/clojure for anything...
16:48	Bronsa	gfredericks: https://github.com/technomancy/leiningen/blob/master/sample.project.clj#L63-L66
16:48	arrdem	(inc Bronsa)
16:48	lazybot	⇒ 54
16:48	gfredericks	(inc Bronsa) ;; semiprimes are cool
16:48	lazybot	⇒ 55
16:48	Bronsa	let them rain
16:49	arrdem	(dec Bronsa) ;; karma/minute rate exceeded
16:49	lazybot	⇒ 54
16:49	johnwalker	(inc Bronsa)
16:49	lazybot	⇒ 55
16:49	gfredericks	Bronsa is going to win an award for karma thrashing
16:49	Bronsa	I know how a rubberband feels now
16:50	arrdem	he's got a loooong way to go before catching up with amalloy..
16:50	gfredericks	~amalloy
16:50	clojurebot	try that; it won't work
16:51	gfredericks	clojurebot: clojurebot is a jukebox for amalloy's greatest hits
16:51	clojurebot	Ik begrijp
16:52	m1dnight_	Dutch \o/
17:00	arrdem	I guess the issue is when if ever does a patched verison of Clojure pay for itself...
17:01	gfredericks	...when you get the feature you need?
17:01	gfredericks	which is immediately?
17:01	arrdem	no as in what features could not be added as libraries.
17:01	arrdem	so.. lets say I wanted a library that adds clojure.core/seqable?
17:01	gfredericks	some of them
17:02	gfredericks	probably mods to the compiler mostly?
17:02	arrdem	probably...
17:02	arrdem	but even then TEJVM is almost good enough, just drag that in and mod it
17:04	gfredericks	$google TEJVM
17:04	lazybot	[CPU count confusion \| VMware Communities] https://communities.vmware.com/message/2334874
17:04	arrdem	$google clojure.tools.emitter.jvm
17:04	lazybot	[clojure/tools.emitter.jvm · GitHub] https://github.com/clojure/tools.emitter.jvm
17:05	gfredericks	oh hey right
17:05	arrdem	that thing that Bronsa and I were working on. all summer.
17:05	gfredericks	worked on so hard you needed some seriously optimized acronyms
17:06	arrdem	that's actually the dev.clojure.org/jira name :/
17:06	gfredericks	oh I like those acronyms actually
17:06	gfredericks	I just don't know them all
17:07	gfredericks	I've been working on TCHECK and NREPL lately
17:10	takemikazuchi	Anyone wanna give me some feedback? I'm working through 4clojure problems: Problem: https://4clojure.com/problem/31 My solution: https://www.refheap.com/91221
17:11	justin_smith	takemikazuchi: conj takes varargs, so you don't need to wrap a call to conj in another call to conj
17:11	justin_smith	,(conj [] :a :b)
17:11	clojurebot	[:a :b]
17:12	gfredericks	,(conj [] conj conj (conj))
17:12	clojurebot	[#<core$conj clojure.core$conj@d4f698> #<core$conj clojure.core$conj@d4f698> []]
17:12	justin_smith	lol
17:12	gfredericks	actually
17:12	gfredericks	,(conj (conj) (conj) (conj) (conj))
17:12	clojurebot	[[] [] []]
17:13	arrdem	rofl
17:14	takemikazuchi	justin_smith: in that case I believe I need to as last of x is a collection that I want to insert y into.
17:16	justin_smith	ahh, I misread, you are right
17:17	justin_smith	well, style wise, if you are using pop, then use peek and not last
17:17	justin_smith	peek/pop butlast/last
17:17	justin_smith	(first/rest)
17:18	gfredericks	+/-, *//, concat/deconcat swap!/unswap!
17:19	justin_smith	heh
17:19	justin_smith	we need unswap!
17:19	gfredericks	launch-missiles/return-missiles
17:19	takemikazuchi	justin_smith: That makes sense, peek does seem more natural there.
17:20	justin_smith	gfredericks: deconcat is clearly (rand-nth [partition partition-all partition-by])
17:20	gfredericks	split-at
17:21	gfredericks	split-with
17:21	justin_smith	oh yeah, those too
17:21	gfredericks	(juxt take drop)
17:27	dbasch	deconcat randomly partitions a sequence so that all possible partitions are equally likely
17:28	arrdem	you could actually define a Concat type and a sane deconcat operator...
17:28	gfredericks	,(defn deconcat [coll] ((juxt take drop) (rand-int (inc (count coll))) coll))
17:28	clojurebot	#'sandbox/deconcat
17:28	gfredericks	,(deconcat (range 10))
17:28	clojurebot	[(0 1 2 3 4 ...) ()]
17:28	gfredericks	,(deconcat (range 10))
17:28	clojurebot	[(0 1 2) (3 4 5 6 7 ...)]
17:29	dbasch	gfredericks: that’s all splits, I mean all possible partitions from all n elements to a single collection
17:34	arrdem	so looks like we define concat in terms of a lazy sequence of cons...
17:34	arrdem	could probably have a Concat type with a seq of subsequences
17:34	arrdem	then deconcat is trivially the sequence of subsequences
17:38	justin_smith	a version of deconcat https://www.refheap.com/91223
17:38	takemikazuchi	Anyone who knows ruby here, is it safe to say Ruby's foo(*bar) and Clojure's (apply foo bar) are functionally equivalent?
17:40	dbasch	justin_smith: but the empty subsequences…
17:40	amalloy	takemikazuchi: yes, they are the same general idea
17:40	justin_smith	dbasch: they are all valid inputs that return the original sequence if you apply concat
17:41	justin_smith	feel free to change the (rand-int n) to (inc (rand-int (dec n))) of course
17:42	takemikazuchi	amalloy: Thanks. Any significant differences I should keep in mind?
17:43	amalloy	takemikazuchi: not really. some nice stuff like apply is a function, so you can do something silly like ##(map apply [+ -] [[1 2 3] [21 7 2]])
17:43	lazybot	⇒ (6 12)
17:44	amalloy	i suppose (partial apply +) would be a more common example
17:44	amalloy	(def sum (partial apply +))
17:47	hiredman	partial apply + 0
17:52	gws	takemikazuchi: can the splat be used on something akin to ##(apply + (range 10))
17:52	lazybot	⇒ 45
17:53	gws	e.g. a hypothetical sum function that takes a variable number of arguments: sum(*[0..9])
17:53	H4ns	in compojure, is there a way to pass both the body-params and a url param to a handler? apparently, if i use vector syntax, i can only access the url parameters (/bar/:foo), whereas when i use map syntax, i can't access the url parameters.
17:53	H4ns	(i want to have a PUT handler which has the ID in the url and the updated data in the request body)
17:54	amalloy	gws: yes, that is like the only thing that splat can do
17:56	dbasch	justin_smith: check this one out https://www.refheap.com/91226
17:56	gws	amalloy: i don't know ruby that well, but i created a vararg sum function and it works when i pass multiple args but with *[0..9] i get "Range can't be coerced into Fixnum" on ruby 2.1.0, so that's why i asked
17:56	dbasch	lazy, uniform random partition
17:59	justin_smith	interesting, so it has 50% chance of size 1, 25% of size 2, 12.5% of size 3 etc. (modulo the bail out if size is greater than remaining contents)
18:00	justin_smith	whereas mine was even within range of size of coll (with same bailout condition)
18:00	amalloy	gws: that's not the syntax for rangers. it's just a really weird number
18:00	amalloy	*ranges
18:00	justin_smith	amalloy: time for the ad&d based dsl for sequences
18:00	takemikazuchi	gws: Yeah I mean the analogy starts to break down at that point I supppose
18:00	dbasch	justin_smith: and mine doesn’t even care about the seq size, or if it’s finite
18:01	justin_smith	right
18:01	dbasch	e.g. (take 10 (random-partition (range)))
18:01	takemikazuchi	lol you end up with something like this: lambda{\|x\| x.inject(:+) }.call((1..9).to_a)
18:01	amalloy	gws: you want (1...9)
18:01	amalloy	takemikazuchi: eh? you don't need the to_a
18:01	takemikazuchi	amalloy: yeah just noticed that.
18:02	amalloy	def sum(*xs) xs.inject(:+) end; sum(1...9)
18:02	amalloy	or something like that
18:02	amalloy	there. def sum(xs) xs.inject(:+) end; sum((1..9))
18:03	dbasch	justin_smith: the 1/2 chance is to guarantee uniformity
18:04	dbasch	can’t think of a better way off the top of my head
18:04	justin_smith	right, just observing the behavior
18:05	justin_smith	could have as easily been thirds (1/3 chance of size 1, 1/6 of size 2, 1/12 of size 3, etc.)
18:05	dbasch	justin_smith: but then it wouldn’t be uniform
18:06	dbasch	I wanted all possible partitions to be equally likely
18:09	dbasch	that would be an awful interview question btw
18:11	dbasch	I should create a library called useless, in the spirit of amalloy’s useful
18:12	dbasch	this could go in there
18:13	dbasch	along with a macro that makes code fail randomly
18:13	dbasch	actually that’s not useless
18:16	amalloy	dbasch: the classic backwards-mode macro belongs there
18:17	amalloy	(defmacro backwards [& body] (cons `do (postwalk (fn [x] (if (seq? x) (reverse x) x)) body)))
18:19	gfredericks	without-redefs
18:20	dbasch	with-open-or-dev-null
18:20	dbasch	maybe-off-by-one-loop
18:21	dbasch	thread-somewhere
18:21	dbasch	-???>
18:22	dbasch	aka as the magical mystery arrow
18:23	dbasch	also aka as
18:24	justin_smith	dbasch: how is 50% chance of size 1 etc. more uniform than 33% chance of zie 1 etc. ?
18:24	dbasch	justin_smith: because there are 2^n partitions
18:25	dbasch	so for example the one with all the elements must occur when you get n tails in a row
18:25	dbasch	technicall 2^(n-1)
18:26	justin_smith	dbasch: clearly there is something I don't yet get about statistics underlying all this
18:26	dbasch	try for example (frequencies (take 10000 (repeatedly #(random-partition (range 4)))))
18:27	dbasch	e.g. for (0 1 2) you have four possibilities
18:27	dbasch	you want to choose ((0 1 2)) with 1/4 chance
18:28	cfleming	arrdem: Without running the patch that I'm running, I can't compile my project
18:28	cfleming	arrdem: So for me the payoff was pretty immediate.
18:29	cfleming	arrdem: That said, technically I only need my patched version to actually compile, not at runtime.
18:38	gfredericks	,(partition-by (fn [_] (rand-nth [true false])) '(0 1 2))
18:38	clojurebot	((0 1) (2))
18:38	gfredericks	,(partition-by (fn [_] (rand-nth [true false])) '(0 1 2))
18:38	clojurebot	((0) (1) (2))
18:38	gfredericks	,(partition-by (fn [_] (rand-nth [true false])) '(0 1 2))
18:38	clojurebot	((0 1) (2))
18:38	gfredericks	,(partition-by (fn [_] (rand-nth [true false])) '(0 1 2))
18:38	clojurebot	((0) (1) (2))
18:38	gfredericks	,(partition-by (fn [_] (rand-nth [true false])) '(0 1 2))
18:38	clojurebot	((0 1) (2))
18:38	gfredericks	o_O
18:39	gfredericks	,(repeatedly 8 (fn [] (partition-by (fn [_] (rand-nth [true false])) '(0 1 2))))
18:39	clojurebot	(((0) (1 2)) ((0 1 2)) ((0 1) (2)) ((0) (1 2)) ((0) (1 2)) ...)
18:39	gfredericks	looks legit
18:40	justin_smith	(inc gfredericks)
18:40	lazybot	⇒ 91
18:40	justin_smith	that's the one
18:41	tuft	anyone know how to do a "where in" style query in datomic? i.e. get entities where an attribute value is one of several
18:41	dbasch	yes, that’s nicer
18:53	AeroNotix_	does/can timbre rotate log files?
18:57	lodin	Anyone know how to restart an nrepl server so that all defs etc are gone? I tried (do (stop-server s) (start-server)) but that didn't help.
18:58	justin_smith	lodin: defs are not local to the nrepl server
18:58	justin_smith	they are global to the clojure process
18:58	lodin	Oh.
19:02	lodin	That actually makes a lot of sense. :-)
19:07	lodin	Is there any tool to start/stop isolated clojure processes easily (which I then can access using nrepl)? I think I've read about such a tool.
19:09	justin_smith	http://leiningen.org/grench.html there is grench, I don't know isolated it is
19:10	truebuddi	quick question here at http://pastebin.com/hpFqRFJ7
19:13	jkj	working with clojure and sampling large data objects, i'd be happy if i had a ide and a repl that wouldn't choke on a few kilobytes of text
19:14	jkj	wonder if there is a middleware to protect emacs from accidentally printint something that takes all the cpu for couple of minutes
19:15	justin_smith	jkj: iirc the issue is that it applies regexes per line, so lack of line breaks make it freak out
19:15	jkj	ok
19:16	jkj	justin_smith: good to know
19:18	jkj	hmm. maybe the trick would be to redirect all the output to something that can take it. web browser maybe
19:19	justin_smith	jkj: you could set debug-on-signal, and then send a signal to emacs via kill in a command line
19:20	justin_smith	jkj: then in the debugger you can see what the hell it was doing
19:20	jkj	justin_smith: thx
19:20	justin_smith	sending problematic output to a text file and opening it in emacs in auto-tail-mode is another option
19:20	justin_smith	it will scroll down as new content is created, but not do the CPU heavy shit it does in the repl buffer
19:21	justin_smith	sorry it's called auto-revert-tail-mode
19:21	justin_smith	or something like that - it is like tail -f but in an emacs buffer
19:21	justin_smith	watches the file and reloads every time it sees a change
19:22	justin_smith	you could use proper logging, and then open the log file using auto-rever-tail-mode
19:22	alexbaranosky_	bbloom :snapshot sounds like a good idea
19:23	lodin	justin_smith: I found https://github.com/projectodd/shimdandy. Unfortunately I can't use it via clojure itself. :-)
19:23	jkj	oops. HUP was a bad idea :D
19:23	justin_smith	jkj: oops
19:28	bbloom	alexbaranosky_: it certainly is :-) works out nice too if your variable is a map, which is a good idea anyway so you can assoc/update-in on each recur, rather than muck with positional arguments
19:28	jkj	i'm not quite sure if printing huge amounts of data slowly or lagging when handling big buffers is really a problem or just trying to misuse emacs
19:29	justin_smith	jkj: it's a problem with the repl buffer, that won't come up in a buffer in plain text mode
19:29	jkj	justin_smith: ok
19:29	justin_smith	do you mean it is lagging for big non-repl buffers?
19:29	tuft	any ideas on testing set membership for an attribute value in datomic? searched all over with no luck
19:30	justin_smith	jkj: if so, in clojure mode or in general?
19:30	cfleming	jkj: if you're an IDE sort of person, Cursive handles lots of output pretty well.
19:31	jkj	cfleming: haven't tried that.
19:33	arrdem	cfleming: fair
19:34	cfleming	arrdem: I had a hideous Rube Goldberg machine hooked up just to be able to compile until I applied that patch.
19:35	jkj	Debugger entered--Lisp error: (wrong-type-argument symbolp [object ede-project-autoload ....
19:35	jkj	quite strange place where it hits after signilng
19:36	arrdem	cfleming: what patch did you need that badly?
19:36	arrdem	cfleming: I have a list of bugbears with Clojure, but nothing that actually stops me getting work done
19:36	jkj	it seems to finish the print and then give backtrace of something else
19:36	jkj	so doing what is does does not stop on signal
19:36	cfleming	arrdem: http://dev.clojure.org/jira/browse/CLJ-1315
19:37	arrdem	cfleming: gotcha
19:37	cfleming	arrdem: Without that patch, I had to bring up the IntelliJ test infrastructure (~45 secs) and compile inside it.
19:38	jkj	now i have stuff in repl buffer and pushin any key takes about 1,5 sek for the character to appear
19:38	arrdem	cfleming: lol
19:38	cfleming	arrdem: And then shower afterwards, which also takes time.
19:38	jkj	any ideas on seeing what it does?
19:38	truebuddi	sorry if already replied .. disconnected earlier but was asking about splitting (-> .... ) into multiple forms.. http://pastebin.com/hpFqRFJ7
19:39	bobpoekert	What are people using for single-machine k-means clustering these days?
19:39	bobpoekert	Still Weka?
19:39	cfleming	arrdem: What's the status of TEJVM these days?
19:40	cfleming	arrdem: Is it realistic to use it to compile?
19:40	arrdem	truebuddi: you need to be threading that request. right now you ignore it. line 19
19:40	arrdem	truebuddi: in future please use refheap, because Raynes made it, it's awesome and it doesn't have ads.
19:41	truebuddi	googling refheap
19:41	arrdem	cfleming: TEJVM totally works, Oxcart is sketchy at best however
19:41	truebuddi	arrdem: thank you will do
19:42	arrdem	cfleming: the main restrictions with TEJVM are either actual bugs in core (incorrect annotations) or just performance. Bronsa has gotten it down to ~15x clojure.core/compile from ~25x but it's still slow.
19:43	arrdem	cfleming: I never had issues when building Oxcart that weren't of my own doing.
19:43	cfleming	arrdem: That's probably ok for a production build if it makes a different though.
19:43	cfleming	s/different/difference/
19:43	arrdem	cfleming: oh. TEJVM can't do AOT yet. Oxcart can, but I never backported the infrastructure for Bronsa
19:43	cfleming	arrdem: Ah.
19:43	arrdem	cfleming: that's another killer
19:44	bobpoekert	Searching around for clustering implementations there's a bunch of stuff that hasn't been updated in years and isn't in maven, adn Weka
19:44	bobpoekert	and stuff like MALLET which is NLP-specific
19:44	arrdem	one of these days I'll have free time and PR it... but not today
19:44	cfleming	arrdem: Did you look at skummet at all? It looked interesting as well and sounds like it was quite successful.
19:44	truebuddi	arrdem: I changed it to https://www.refheap.com/91230 but still getting cemerick.friend$authenticate$fn__379 cannot be cast to java.util.Map
19:45	arrdem	truebuddi: you have a type error somewhere. you are passing a function where it expects a map. more than that I cannot trivially surmise.
19:46	kenrestivo	~tejvm
19:46	clojurebot	It's greek to me.
19:46	kenrestivo	me too
19:46	arrdem	truebuddi: I would guess line 12
19:46	arrdem	truebuddi: check your arguments order with ->
19:46	arrdem	cfleming: meh totally not biased in this or anything but I think that skummet is a hack/wrong approach
19:47	arrdem	cfleming: have you seen my end of summer blag post?
19:47	cfleming	arrdem: Sure, but it's one that might produce decent gains with relatively little work.
19:47	cfleming	arrdem: No, got a link?
19:48	arrdem	cfleming: http://arrdem.com/2014/08/05/of_oxen,_carts_and_ordering/
19:48	arrdem	cfleming: https://groups.google.com/forum/#!topic/clojure-dev/dSPUNKSaV94
19:48	arrdem	cfleming: those two pretty well capture my takeaway from this summer
19:49	cfleming	arrdem: Ah, I lie, I did see the mailing list post. I think the proposal to split out core sounds good.
19:50	arrdem	no way it's gonna happen.. but it would be nice
19:50	arrdem	^ one line summary of my summer :/
19:51	cfleming	arrdem: I didn't realise that one of the main benefits of Oxcart was to remove var indirection - nice.
19:53	truebuddi	arrdem: converting the defn to a def worked ... https://www.refheap.com/91230 thanks!
19:54	arrdem	cfleming: as I argued in the clj-dev post, skummet and "lazy loading" can only approximate an actual tree shaking compiler, and do so at the cost of creating a difficult to maintain fork of Clojure.
19:55	arrdem	cfleming: if the world were flat and I had my way, we'd do lib-clojure and then Mikera and I would be free to build crazy clojure-like fast languages
19:55	arrdem	but it isn't
19:55	cfleming	arrdem: Yeah, no doubt. I'd love to be able to make a totally static production build of Cursive for deployment though.
19:55	cfleming	arrdem: I guess there's nothing stopping you doing it except time and money, right? :-)
19:56	justin_smith	jkj: not sure actually, if just seeing where it was when you interrupted did not help
19:56	justin_smith	jkj: #emacs could have some ideas
19:57	arrdem	cfleming: basically. mainly money as it can buy time... if someone wanted to foot the bill for this I'd be delighted to say fuckit, maintain my lib-clojure fork and keep working on Oxcart but GSoC is over
19:57	arrdem	cfleming: that and I think if you're gonna statically compile Clojure may as well take the time to clean up some warts
19:58	arrdem	I have a project that's my sketch of doing so, but it doesn't work and I'm not sure it'll ever exist so I'll refrain from advertising it here.
20:00	cfleming	arrdem: I'd be interested in hearing about it - are you going to the conj?
20:01	arrdem	cfleming: I probably will but I don't have plans yet.
20:01	cfleming	arrdem: Ok, I'll buy you a beer if you make it and you can tell me about it.
20:01	arrdem	cfleming: haha you're on
20:02	arrdem	after seeing all the cool stuff from strangeloop I'd be crazy to miss the conj... but classes and stuff
20:03	cfleming	arrdem: Yeah, I have to make it to strangeloop one of these days, it looks amazing.
20:04	cfleming	arrdem: Almost more interesting than the conj actually, more eclectic
20:04	arrdem	cfleming: yeah it was really interesting to see all the hot stuff from different languages and communities. I've been looking at the conj schedule and due to having a single track there's something for everone
20:17	bobpoekert	I found a library that was updated this year! The documentation is all in japanese.
20:18	bobpoekert	oh, and it only works on 2d vectors :(
20:18	TEttinger	(inc Japanese)
20:18	lazybot	⇒ 1
20:19	TEttinger	what are you looking for, bobpoekert? something in core.matrix?
20:19	bobpoekert	something that can take 27-dimensional
20:19	bobpoekert	vectors of reals
20:19	bobpoekert	and turn them into a k-means tree
20:19	bobpoekert	whether it's in core.matrix or not I don't really care
20:21	justin_smith	(inc 日本の)
20:21	lazybot	⇒ 1
20:22	TEttinger	I saw a japanese version of https://github.com/joshuaeckroth/clj-ml
20:23	justin_smith	bobpoekert: this looks a little dated, but it does look like what you are looking for http://www.informatik.uni-ulm.de/ni/staff/HKestler/parallelkmeans/
20:24	justin_smith	it's not really idiomatic as a clojure project, but it is doing k-means and has source code you can start with
20:24	bobpoekert	TEttinger: I was referring to https://github.com/satoh-disk/k-means
20:29	TEttinger	there seem to be a bunch of leads. https://github.com/elben/k-means
20:30	bobpoekert	that's 2d
20:30	bobpoekert	justin_smith's suggestion might work
20:30	TEttinger	I am not familiar with k-means at all, so I'd go with justin_smith's then. I also found https://github.com/codyrioux/kmeans-clj
20:31	bobpoekert	numeric processing with core.async???
20:31	lazybot	bobpoekert: Oh, absolutely.
20:34	bobpoekert	it should really be more common knowledge that (apply min-key …) is argmin
20:34	bobpoekert	took me a long time before I found that out
20:34	bobpoekert	min-key and max-key are really confusingly names
20:34	bobpoekert	named
20:37	justin_smith	yeah, I wonder what the origin of the current names is?
20:49	gfredericks	min-by and max-by would be less surprising I guess?
20:54	justin_smith	or argmin and argmax, which is what they are called in math
20:54	hodlr	in order to pull in java libs into my project what do i need to enter into project.clj from the pom.xml ?
20:54	justin_smith	hodlr: [group/project "version.id"]
20:55	justin_smith	err, that was sloppy
20:55	justin_smith	[groupId/artifactID "version"]
20:56	hodlr	justin_smith: thanks :)
20:56	gfredericks	justin_smith: I'm kind of surprised I never noticed those names in math
20:57	justin_smith	gfredericks: http://en.wikipedia.org/wiki/Arg_max
20:58	justin_smith	it's the only standard name for the function I know of
20:58	justin_smith	I guess technically arg-min and arg-max could be like min-key / max-key but take collections and return sets
20:59	justin_smith	(the set of all items returning the minimum value)
20:59	justin_smith	(or maximum)
20:59	gfredericks	HUH.
20:59	gfredericks	(inc justin_smith)
20:59	lazybot	⇒ 85
21:00	justin_smith	actually planet math is usually a better source than wikipedia http://planetmath.org/argminandargmax
21:02	justin_smith	actually, to be most mathematically correct, we could (intern 'clojure.core (symbol "arg max") #(hash-set (apply max-key %)))
21:02	justin_smith	but it would be a pain in the ass to use something with a name like that in actual code
21:03	justin_smith	,(intern ns (symbol "arg max") #(apply max-key %&))
21:03	clojurebot	#'sandbox/arg max
21:04	gfredericks	somebody at work was asking about the behavior of ##(keyword "foo bar") and why it doesn't throw
21:04	lazybot	⇒ :foo bar
21:04	gfredericks	does anybody know if the answer is A) only backwards compatibility, B) speed (from not checking), C) something else?
21:04	justin_smith	we've had similar discussions around here
21:05	TEttinger	,((keyword "Oh yeah: I heard the best news!") {(keyword "Oh yeah: I heard the best news!") "Oh really?"})
21:05	clojurebot	"Oh really?"
21:05	TEttinger	they certainly are valid
21:06	justin_smith	,(intern ns (symbol "arg max") (fn [key sq] (apply max-key key sq)))
21:06	clojurebot	#'sandbox/arg max
21:06	justin_smith	,((resolve (symbol "arg max")) #(* % %) [-10 1 2 3 4])
21:06	clojurebot	-10
21:06	gfredericks	sure but there are uses where they don't
21:07	gfredericks	e.g., if you like to just blindly parse your json into keywords, that might work okay most of the time, but as soon as you start using cascalog or storm things break
21:07	gfredericks	since they're serializing things behind the scenes
21:07	justin_smith	right. and the blindly parsing json into keywords thing may just be the source of the permissive behavior?
21:08	gfredericks	"source of"?
21:08	justin_smith	maybe "a justification for"
21:08	justin_smith	sloppy wording
21:09	gfredericks	well it certainly sets up the "changing this would break lots of code" argument
21:10	gfredericks	which I figured is a good enough explanation for not expecting anything to change at this point; but I wasn't sure if it was universally regretted or not.
21:13	justin_smith	tangentially, I wonder if something related to this (any string becoming a symbol / keyword) couldn't have been exploited to make gensyms a bit stronger (eg. rendering them unreadable)
21:13	justin_smith	I think I meant ie.
21:17	gfredericks	haha that's clever
21:17	gfredericks	so they're guaranteed to not clash
21:17	gfredericks	could make some fringe uses more difficult though
21:18	justin_smith	yeah
21:18	bbloom	gfredericks: it's speed / not bothering to do error checking b/c it's hard
21:18	bbloom	and of course can't change now b/c ppl depend on broken behavior
21:18	bbloom	but keywordizing strings when parsing json is a universally bad idea without a known schema
21:19	bbloom	and a marginally bad idea with a schema too :-P
21:22	gfredericks	bbloom: error checking isn't hard in this case, is it? just arm thyself with a decent regex?
21:22	bbloom	gfredericks: problem isn't "this case" it's universally
21:23	bbloom	if you make a promise to check your arguments for validity, you get in to the whole type systems, contracts, schemas, etc etc etc forever
21:23	bbloom	seems the line for clojure was drawn: "only check arguments when there's a high likelihood that somebody will fuck up AND it doesn't slow the whole thing down"
21:24	bbloom	"but mostly only when a macro will eat the line numbers of your stack trace"
21:24	bbloom	:-P
21:30	Wild_Cat	while we're on that topic, I'm curious, why was the decision taken to keywordize strings?
21:31	gfredericks	bbloom: coolthx
21:31	gfredericks	Wild_Cat: in what case?
21:32	Wild_Cat	gfredericks: JSON deserialization.
21:32	justin_smith	that's optional
21:32	justin_smith	always has been
21:32	Wild_Cat	wait, it is?
21:32	bbloom	there's a keywordize? argument
21:32	Wild_Cat	hrmm. I'm misremembering. Disregard my question and carry on, then.
21:33	Wild_Cat	it's been too long since I got the occasion to write actual Clojure code.
21:33	bbloom	the argument is discussed in the api docs
21:33	bbloom	but not the readme
21:33	bbloom	but it should be :-P
21:36	gfredericks	bbloom: I'm looking for such an argument in the cheshire docstrings but can't find it; is that where you were referring to?
21:37	bbloom	core.data.json
21:37	bbloom	i assumed that's what Wild_Cat was referring to
21:37	bbloom	sorry
21:37	Wild_Cat	bbloom: it was.
21:37	bbloom	oh then NOT sorry :-)
21:41	bbloom	gfredericks: the read-json function
21:44	gfredericks	bbloom: oh dear I think I misinterpreted the word "argument"
21:44	bbloom	gfredericks: ha! seems you need some sleep my friend
21:44	gfredericks	this morning I slept in till 6:30
21:44	hugoduncan	in cheshire you can pass in an arbitrary function to apply to keys
21:50	justin_smith	hugod: which could as easily be a validator as a keywordizer :)