#clojure – 2011-02-08

2011-02-08

00:44	defn	first madison, WI #clojure meetup, complete.
01:04	bartj	er, I am not able to understand the difference b/w re-find and re-matches
01:05	amalloy	##(doc re-find) ##(doc re-matches)
01:05	sexpbot	(doc re-find) ⟹ "([m] [re s]); Returns the next regex match, if any, of string to pattern, using java.util.regex.Matcher.find(). Uses re-groups to return the groups."
01:05	sexpbot	(doc re-matches) ⟹ "([re s]); Returns the match, if any, of string to pattern, using java.util.regex.Matcher.matches(). Uses re-groups to return the groups."
01:05	clojurebot	"([m] [re s]); Returns the next regex match, if any, of string to pattern, using java.util.regex.Matcher.find(). Uses re-groups to return the groups."
01:05	clojurebot	"([re s]); Returns the match, if any, of string to pattern, using java.util.regex.Matcher.matches(). Uses re-groups to return the groups."
01:06	amalloy	whoops. silly bots
01:06	defn	$(doc re-groups)
01:06	defn	#(doc re-groups)
01:06	defn	...
01:06	defn	,(doc re-groups)
01:06	clojurebot	"([m]); Returns the groups from the most recent match/find. If there are no nested groups, returns a string of the entire match. If there are nested groups, returns a vector of the groups, the first ...
01:06	amalloy	bartj: re-find lets you reuse a matcher object
01:07	amalloy	to search the same string multiple times (though usually you'd prefer re-seq)
01:10	bartj	for all practical purposes, re-seq seems pretty similar to re-matches
01:10	bartj	except that re-seq puts the whole match in a seq
01:15	bytecolor	am I correct in assuming there is no way to seed the core random functions? rand, rand-int, and rand-nth
01:16	bytecolor	since they use the rand method of Math, which creates an instance of java.util.Random, afaik
01:38	defn	bytecolor: http://richhickey.github.com/clojure-contrib/probabilities.random-numbers-api.html ???
03:43	Arelius	Excuse me if this question shows a terriable misunderstanding of how variable bindings work but:
03:43	Arelius	I have a function that I call a bunch to populate a list, this is only done once at load-time.
03:44	Arelius	Do I have to wrap it in a ref or atom or some such, or is constantally re (def ...) ing it going to work?
03:44	Arelius	It seems to work fine, but I am also running it from SLIME, so I don't know if that's always going to be the case.
03:45	brehaut	Arelius: if i understand what you are saying, i think theanswer is no. but can you please give an example of your usage?
03:45	Arelius	brehaut: yeah....
03:45	brehaut	am i correct that you are not redefining your list?
03:46	Arelius	Well, I am, second
03:46	brehaut	eg you are doing something like (def my-list (my-complex operation))
03:48	Arelius	Something simple like this: https://gist.github.com/816118
03:48	brehaut	defun ?
03:48	Arelius	defn
03:48	Arelius	sorry
03:48	brehaut	np
03:49	Arelius	I come from a Common Lisp background.
03:49	brehaut	i think that will actually work in clj1.2
03:49	brehaut	but not in 1.3 unless you explicity set the var to dynamic
03:49	brehaut	however i wouldnt recommend it
03:50	Arelius	So, all the appending to the list will pretty much happen at initialization time. so it seems a bit overkill to wrap it with a ref or something.
03:50	Dranik	Arelius, that is awfully not idiomatical
03:51	Dranik	you should firstly compute the whole list and only then bind it to L
03:51	Dranik	since all the data is persistent
03:51	Dranik	it can't be changed
03:51	Arelius	Dranik: Ideally, yes...
03:51	Arelius	But I'd like to be able to create it from Macros littered through the code.
03:51	brehaut	yikes
03:51	Arelius	and having to constrain all the macros to one place would be less than ideal.
03:52	Dranik	Arelius, if you are totally sure you need a mutable variable then use refs
03:52	Dranik	it's easy
03:52	brehaut	Arelius: its not overkill to be explicit about your mutables in clojure
03:52	Dranik	Arelius, but your gist seems to me simple and you may use persistent data
03:52	brehaut	even if they only mutate at load time
03:53	Arelius	Well, I could solve the problem without mutables by writting a pre-processor that would look for all instances of (add-item ...) and put them into a single place.
03:53	Arelius	For instance.
03:53	brehaut	Arelius: use use a ref or var
03:53	brehaut	s/use use/just use/
03:53	sexpbot	<brehaut> Arelius: just use a ref or var
03:54	Arelius	Ok, I can do that. I just figured there would be a better way to do that sort of thing.
03:54	brehaut	s/var/atom/
03:54	brehaut	it denotes clearly to any reader that the var is subject to change
03:54	Arelius	Would it change it if add-item were a macro?
03:54	brehaut	IMO no
03:54	Dranik	Arelius, guess it's ok to use mutables in macross
03:55	Dranik	bcs it is totally another environment. single-threaded usually
03:55	brehaut	Arelius: the other option is using the earmuffs idiom
03:55	Arelius	earmuffs?
03:56	brehaut	(def ^:dynamic my-munged-var [])
03:56	brehaut	and use set! rather than def
03:56	brehaut	oh
03:56	brehaut	huh
03:56	Arelius	How is that differen't then ref?
03:57	brehaut	a ref is an STM variable
03:57	brehaut	it can only be updated in a transactional context
03:57	brehaut	and it is coordinated with any other transaction editing the same ref, and any other refs in the same transaction
03:58	brehaut	Arelius: see http://clojure.org/vars http://clojure.org/refs and http://clojure.org/atoms
03:58	Arelius	How are dynamic variables protected?
03:58	Arelius	brehaut: I read all those, have no idea how dynamic fits into it.
03:59	brehaut	dynamic is metadata
03:59	brehaut	otherwise your hack is going to stop working in 1.3
03:59	Arelius	hmm...
03:59	brehaut	in clj 1.2 and lower vars are as dynamic as possible by default
03:59	brehaut	in 1.3 they are static by default and dynamic with meta data
03:59	Arelius	Anyways, I tried to flesh out the example a bit, incase this gives you a better understanding: https://gist.github.com/816134
04:00	brehaut	if you try that code with what you have now split over two files it definately wont work
04:00	Arelius	Because of namespaces?
04:00	brehaut	yes
04:01	Arelius	Sure, it's not a compilable example, but I think it otherwise gets the point across?
04:01	brehaut	yes
04:01	brehaut	its not much different to multimethods
04:01	Arelius	Yes
04:02	brehaut	honestly though, i think an atom is probably simpliest
04:02	Arelius	How are the decleration of multi-methods updated?
04:02	brehaut	theres a mutable object behind the scenes
04:03	Arelius	with like dynamic, ref, atom, etc?
04:03	brehaut	clojure.lang.MultiFn
04:03	brehaut	its possible to create something similar using deftype i believe
04:04	brehaut	(deftype is the low level abstraction implementation feature)
04:05	Arelius	Sure, so deftype, and some sort of mutable object?
04:05	brehaut	deftype _is_ the mutable object
04:05	Arelius	Ohh, hmm
04:05	brehaut	but seriously, just use an atom
04:06	brehaut	its much easier, its all you'll need, its thread safe
04:06	brehaut	and its very little overhead
04:06	Arelius	Ok, I can do that
04:07	brehaut	(def L (atom []) (defn addItem [i] (swap! L #(conj % i)))
04:07	Arelius	Also, any links on the dynamic metadata, not sure I understand that yet.
04:07	brehaut	dont worry about it then
04:07	brehaut	its just something you would have to encounter if you went down the var route
04:08	Arelius	brehaut: Sure. I still would like to understand what it is, so if I ever encounter, or have a reason to in the future.
04:08	brehaut	its real simple
04:08	brehaut	^ is the metadata reader macro
04:08	brehaut	it attaches the next form as metadata to the form after
04:08	Arelius	Sure, but about the annotation itself, how that works. and when dynamic variable break.
04:09	brehaut	:dynamic affects vars, and only vars in clojure 1.3 (currently in alpha)
04:09	Arelius	I assume they break when I try to touch them in threads. But I'm not very clear why. are they really just fully mutable?
04:09	brehaut	no in 1.3 they are static by default
04:09	brehaut	once defined, you cannot redefine them
04:09	Arelius	less I set them as :dynamic.
04:09	brehaut	exactly
04:10	Arelius	So, that'd allow me to change the decleration. In what manner does that break when I have threads running.
04:10	brehaut	threads are different
04:10	brehaut	atoms or refs will provide thread safety
04:11	brehaut	vars do not traverse thread boundaries
04:11	Arelius	Ahh...
04:11	brehaut	(or more correctly, _changes_ to bindings do not)
04:11	Arelius	So, if I have another thread running, it wouldn't catch the variable update?
04:11	brehaut	correct
04:12	Arelius	but presumablly, if I create another thread after updating the decl. that thread should have the new decl?
04:12	Arelius	from, of course the thread it was updated in.
04:12	brehaut	yes
04:12	Arelius	Ok. that makes sense. thanks.
04:13	brehaut	no worries
04:36	TobiasRaeder	morning
05:39	Jewtaeus_maximus	Hi, I'm completely and utterly new here, why doesn't clojure support TCO?
05:45	AWizzArd	Jewtaeus_maximus: because the JVM doesn't support this.
05:46	AWizzArd	Jewtaeus_maximus: but for all practical purposes you can use Clojure as if it supported TCO. CLJ has 'recur' and trampolines.
05:46	Jewtaeus_maximus	AWizzArd, how do trampolines work?
05:52	AWizzArd	Jewtaeus_maximus: http://goo.gl/yuCiO
05:55	ejackson	Jewtaeus_maximus: also, in Clojure, you rarely want to write in a 'Schemey' style. Rather use the seq abstraction either by constructing your only lazy-seqs or using the myriad built in functions.
05:57	ejackson	so you end up not needing TCO
06:18	Jewtaeus_maximus	So trampoline is more or less: (defn trampoline [f] (if (Fn? f) (recur (f)) f))), AWizzArd?
06:24	clgv	Jewtaeus_maximus: almost. have a look here: https://github.com/clojure/clojure/blob/b578c69d7480f621841ebcafdfa98e33fcb765f6/src/clj/clojure/core.clj#L5040
06:26	Jewtaeus_maximus	So f you do (trampoline 3) it reports an error?
06:26	clgv	&(trampoline 3)
06:26	sexpbot	java.lang.ClassCastException: java.lang.Integer cannot be cast to clojure.lang.IFn
06:26	clgv	yes^^
06:28	Jewtaeus_maximus	What if I want the final return value of some mutual recursion to be a funtion?
06:29	clgv	maybe, you could wrap into some data. but does it really makes sense that way?
07:44	AWizzArd	$seen rhickey
07:44	sexpbot	rhickey was last seen quitting 18 hours and 20 minutes ago.
07:47	AWizzArd	Btw, to the +/- 50 german users: There is also a #Clojure.de channel.
08:19	Vinzent	flatten always saves order of the elements in coll, right? e.g. things like (flatten [[1 2][3 4]]) always results in (1 2 3 4)?
08:44	opqdonut	Vinzent: that's the idea, yes
08:44	MoUsSoR	hi, can somebody help me here about a jreality pb ... ?
08:46	Vinzent	opqdonut, ok, i just wanted to make sure
09:04	rahcola	are sorted-sets homogeneous only?
09:05	rahcola	&(sorted-set :a 1 :b)
09:05	sexpbot	java.lang.ClassCastException: clojure.lang.Keyword cannot be cast to java.lang.Number
09:06	ejackson	rahcola: if you use a sorted-set-by you can pass a Comparator that can handle inhomogenous sets, otherwise, no.
10:02	khali	I'm putting a jar in lib/ and calling lein uberjar doesn't include it in the final jar. Any ways around this?
10:04	mefesto	khali: you probably have to install that jar first then include it as a dependency in your project.clj. just my guess.
10:05	mefesto	khali: is this a jar that isn't available on any repository (clojars, maven) ?
10:06	khali	yes it is available but it's a newer version than those
10:07	mefesto	khali: this is probably the long way around of doing this (i'm not too familiar with all lein's features) but if you have maven installed you can update your local repository with the jar yourself (e.g. mvn install:install-file)
10:08	mefesto	once you do that and specify the groupId, artifact, etc then you can depend on that specific version in your project
10:09	mefesto	that's what we do here with some proprietary libs (like oracle's jdbc driver) that aren't available on maven
10:09	khali	mefesto, cool thanks, i'll try that!
10:22	clgv	khali: but putting a jar in the lib directory should work to. it does here. maybe your project.clj specified a different directory name?
10:23	khali	well when i put it into libs after calling lein it actually gets deleted, and that's without mentioning it in the project.clj file..
10:23	mefesto	any ring users around?
10:25	clgv	khali: ah well I know that behaviour. add the following to your project.clj: :disable-implicit-clean true
10:28	khali	clgv, oh that did the trick, cheers.
10:36	khali	hm, final question. im slime how do i change to a given namespace?
10:38	raek	khali: C-c M-p
10:39	TimMc	So, I'm going to try to write a Swing app in Clojure. I know a little about Refs and a reasonable amount about threading in Java. Where should I start?
10:39	TimMc	(I.e. I have no idea how to use Clojure's concurrency idioms for this.)
10:40	khali	TimMc, i'm attempting the same thing :)
10:40	khali	raek, legend, now i'm set!
10:46	TimMc	khali: Have you made progress on it?
10:50	bartj	is there a light-weight Clojure library to do mean/median computations other than incanter ?
10:50	bartj	*are
10:51	khali	TimMc, kind of, i first wrote it using netbeans with enclojure, and did the gui using matisse. now i'm trying to do using clojure only and laying it out using miglayout
10:53	khali	TimMc, but i'm very new to clojure.. only started learning it a few days ago :)
10:56	TimMc	khali: Roughly the same here.
10:57	TimMc	I've written a graphics app in Clojure before, but not one with interactivity or concurrency.
10:57	TimMc	Just one big window with a non-animated (but dynamically generated) drawing.
10:58	khali	TimMc, have you looked at the ants example? wonder if that would give some clues..
10:58	odyssomay	TimMc, khali http://www.dreamincode.net/code/snippet3252.htm
10:59	khali	odyssomay, cheers!
11:00	TimMc	odyssomay: Ah, that looks helpful -- it has explicit global state, which the temperature converter example does not.
11:01	TimMc	I see that there are some dosync blocks with side-effects -- is that kosher?
11:01	Chousuke	hmm
11:01	Chousuke	probably not
11:03	Chousuke	I doubt that code is correct in the general case
11:04	khali	chouser, whats the general principle to obey?
11:04	khali	Chousuke, rather
11:04	Chousuke	no side-effects whatsoever in dosync blocks :P
11:05	dnolen	Clojure + Swing using agents - http://stuartsierra.com/2010/01/08/agents-of-swing
11:05	Chousuke	the event handlers won't probably get executed in multiple threads simultaneously but you might get retries at the very least
11:06	Chousuke	so you'd get a number of redundant .grabFocus and .setText calling.
11:07	Chousuke	integrating a stateful UI library with Clojure's STM and functional programming unfortunately isn't trivial :(
11:07	Chousuke	I guess agents are a good bet
11:07	Chousuke	update data in a functional way, send UI updates to an agent which then applies them.
11:09	TimMc	My program will have a drawing canvas and some buttons, with user interaction constrained by global state.
11:09	Chousuke	though if you absolutely must never have the UI go out of sync with the data model even for a moment, even that might not work :/
11:09	raek	khali: TimMc: check out c.c.swing-utils (especially the do-swing fn) for executing gui code in the swing thread (which swing requires)
11:09	TimMc	The most difficult interaction will be when the user is dragging stuff on the canvas.
11:09	Chousuke	yeah.
11:11	raek	this is how I do it for a small project: https://github.com/raek/thiudinassus/blob/master/src/thiudinassus/graphics.clj#L168
11:11	TimMc	This will be a double-buffered canvas. If I keep updating the state of some global Ref from the event thread, could I use an agent to update the canvas image?
11:11	raek	pics: http://raek.se/thiudinassus/
11:11	raek	(very basic, though)
11:14	gfrlog	is there a function in the core libraries or contrib for getting a list of files in the filesystem?
11:15	clgv	java.io?
11:15	gfrlog	like (clojure.contrib.shell-out/sh "ls")
11:15	fliebel	morning
11:15	gfrlog	yes of course java -- that's what I was trying to avoid
11:16	hoeck	gfrlog: maybe file-seq ? was once there as an example of using tree-seq
11:16	gfrlog	,(doc file-seq)
11:16	clojurebot	"([dir]); A tree seq on java.io.Files"
11:17	gfrlog	hoeck: that looks quite promising, thank
11:17	gfrlog	s
11:17	clojurebot	I don't understand.
11:17	raek	gfrlog: the File class has a method for that
11:18	raek	ah, just read "that's what I was trying to avoid"
11:18	gfrlog	yeah -- it seemed like the sort of thing that is common enough to have been wrapped already
11:18	hoeck	raek: how is that colortheme called? (on those screenshots)
11:18	raek	clojure tends to not add something when a working version exists in java-land
11:19	raek	hoeck: tangotango
11:19	hoeck	raek: thx
11:19	raek	don't have the URL atm. there exists multiple versions, I think.
11:20	raek	it is problably this one: http://orgmode.org/worg/color-themes/color-theme-tangotango.el
11:21	hoeck	raek: just found a one on github too, looks nice and I need some change :)
11:21	khali	hm, swank-clojure-project hangs on 'Polling "/tmp/slim.10147" .. (Abort with
11:21	khali	M-x slime-abort connection')
11:22	khali	i've started swank using lein swank in the project directory though
11:24	fliebel	Has anyone in here followed the async ring discussion( http://groups.google.com/group/ring-clojure/browse_thread/thread/243f452c915356c8/ ) a bit? I would like to understand what is proposed here, since Ring does already support OutputStreams and lazy seqs. There was one short message that mentioned this, and talked about duplex, what is meant by this?
11:26	raek	khali: if you have started swank manually, connect to it with slime-connect
11:27	khali	raek, i tried that but it cant 'see' the namespace of my app (in the repl)
11:27	raek	khali: have you loaded it?
11:28	raek	i.e. pressed C-c C-k in the source file buffer or executed (require 'the-ns)
11:29	raek	or, what do you mean by "see"?
11:30	gfrlog	isn't there a macro-thing like (let) that lets all the bindings refer to eachother?
11:30	pdk	binding probably does that
11:31	pdk	letfn if it's all functions and you need them to refer to each other
11:31	gfrlog	maybe "...that allows all the bindings..." is a less confusing way to say that
11:31	fliebel	gfrlog: letfn might be useful.
11:31	gfrlog	thanks
11:31	raek	gfrlog: in let, a binding can refer to previously letted values
11:31	gfrlog	raek: I have a pair that are mutually dependent
11:31	gfrlog	my first solution was to use an atom, which is terrible
11:31	raek	gfrlog: but letfn allows you to let a number of functions that are mutually recursive
11:32	khali	raek, require worked
11:32	khali	raek, im ok now
11:32	raek	gravity: let is works immutably, and immutable values cannot be mutually referring
11:33	fliebel	gfrlog: If you feel hacky, you can try #'symbol, or let one of them as nil first, or whatever.
12:04	willtim	hi guys, is this a bug in clojure?
12:04	KirinDave	willtim: This irc message?
12:05	willtim	for [:let [xs [1 2 3]] x xs] x)
12:06	willtim	i.e. :let does not work as the first binding
12:06	willtim	which can be useful sometimes and saves nesting
12:08	jkkramer	willtim: :let, :while, and :when are modifiers of the binding (you can have different modifiers for each binding), so no
12:17	willtim	@jkkramer, yes makes sense, thanks
12:20	khali	it was painful to setup but now that i have, slime+clojure rules for swing programming.. :)
12:20	odyssomay	Does 'send' spawn a new thread?
12:24	odyssomay	Hmm, it seems like it uses a thread from a thread pool
12:24	ejackson	odyssomay: send-off starts a new thread entirely, I believe
12:25	odyssomay	ejackson, ok, thanks
12:29	willtim	@jkkramer, interestingly, haskell does not have this limitation and guards can be at the top of a comprehension (checking input)
12:35	jkkramer	willtim: i think using (let [xs ...] (for [x xs] ...)) is clearer anyway. your way messes with my internal dialog: "for let something x in xs ..."
12:36	TimMc	willtim: macro time! :-P
12:53	weilawei	http://pastie.org/1541676 < I get "java.lang.ClassCastException: java.lang.Integer cannot be cast to clojure.lang.IFn" when attempting to run iter-fib (on anything, seemingly). It's an exercise from SICP. What am I missing?
12:54	weilawei	Never mind, got it.
12:55	weilawei	Tried to evalulate a value. >_<
12:55	TimMc	OK, what's the difference between ^String and #^String in the arguments to a function?
12:56	jkkramer	TimMc: #^String is the old, deprecated way of type hinting
12:57	TimMc	Gotcha.
13:25	jweiss	this page seems to be out of date: http://clojure.org/protocols
13:25	jweiss	talks about 1.2 being unreleased
13:31	khali	am i missing something or is there no function to find the length of a sequence?
13:31	odyssomay	khali, count
13:31	khali	ooh
13:32	odyssomay	;) it was the same for me
13:32	khali	it makes sense, i guess sometimes you need to compute it, and count is more precise
13:34	{aaron}	hi. what does a - in front of a function name mean?
13:34	{aaron}	e.g. http://codingkata.org/katas/unit/hello-world/solutions/view/8
13:35	amalloy	{aaron}: by default, gen-class causes -foo to become MyClass.foo, i believe
13:36	{aaron}	ah
13:36	{aaron}	that makes sense, thanks
13:36	amalloy	khali: you can also use ##(counted? (range 10)) to determine whether the count will be fast or not
13:36	sexpbot	⟹ false
13:39	khali	amalloy, over my head atm, but i'll jot it down for later
13:40	TimMc	khali: counted? tells you whether a collection computes its count in constant time.
13:40	amalloy	khali: lists and vectors store their count in every node, so that (count some-vec) takes constant time; lazy sequences can't do that of course
13:40	khali	oh understood :)
13:41	khali	i meant the usage of ## there
13:41	amalloy	oh that just triggers sexpbot
13:41	khali	ah
13:41	TimMc	so ##3 should give me...
13:41	amalloy	TimMc: nope, sorry
13:41	TimMc	maybe ##(+ 2 3) then
13:41	sexpbot	⟹ 5
13:41	TimMc	ah
13:42	amalloy	&3 though, of course
13:42	sexpbot	⟹ 3
13:42	TimMc	Why of course?
13:42	amalloy	well
13:42	amalloy	starting a message with & is an unambiguous "sexpbot do this for me" command
13:42	TimMc	Got it.
13:42	amalloy	the ##hashmarks might be referring to ##java, for example, so he only wakes up if the thing you're trying to eval is a sequence of some kind
13:43	TimMc	Good point. And I see that clojurebot responds to , as a command trigger.
13:43	amalloy	indeed
13:44	amalloy	well, an eval trigger, anyway. sexpbot has a separate "command" structure starting with $, and clojurebot treats ~ as command
13:44	amalloy	$seen cemerick
13:44	sexpbot	cemerick was last seen quitting 16 hours and 59 minutes ago.
13:45	TimMc	Back to type hints... I have a vector (currently of known length) of Point2D$Double that I am decomposing in a let and using in Java graphics calls.
13:45	TimMc	I'd like to get rid of reflection here. Is there a way to mark the whole vector as only containing Point2D$Double, or will I have to hint that each thing I take out is an instance of that?
13:46	amalloy	TimMc: the latter
13:46	amalloy	or you can copy it all into a native java array and type-hint that
13:46	TimMc	Ah, I'll keep that in mind!
13:47	amalloy	though the syntax for type-hinting it will be pretty gross iirc
13:47	amalloy	&(import java.awt.Point2D$Double)
13:47	sexpbot	java.lang.ClassNotFoundException: java.awt.Point2D$Double
13:48	amalloy	&(import java.awt.geom.Point2D$Double)
13:48	sexpbot	⟹ java.awt.geom.Point2D$Double
13:48	khali	is there a way to treat a struct as an array of values?
13:48	amalloy	khali: (vals struct)
13:48	amalloy	&(class (into-array [(Point2D$Double. 10 10)]))
13:48	sexpbot	⟹ [Ljava.awt.geom.Point2D$Double;
13:49	khali	perfect amalloy
13:50	amalloy	so TimMc, your type-hint would look like (let [^"[Ljava.awt.geom.Point2D$Double" hinted-val (into-array ...)] (use hinted-val))
13:50	TimMc	eep
13:51	amalloy	heh, indeed. hinting arrays and/or primitives is a pain
13:51	TimMc	...and then I'd still have to use Java interop calls to pull stuff out of the array.
13:51	amalloy	TimMc: well, aget isn't so bad
13:52	TimMc	Can I destructure arrays?
13:52	amalloy	TimMc: sure, but then you've lost the type-hinting
13:52	TimMc	urgh
13:53	TimMc	Is that something that could be changed?
13:54	amalloy	ummmmm, i don't know
13:54	TimMc	It seems reasonable, but then I'm not the one writing Clojure's compiler.
13:54	amalloy	TimMc: well, if it is possible it shouldn't have to involve java at all
13:55	amalloy	$source let
13:55	sexpbot	let is http://is.gd/DlvwkU
13:56	amalloy	let and/or destructure might be able to get at the :tag metadata and inspect it for arrays
13:56	TimMc	Oh right, it's the macro that would have to do this.
13:57	TimMc	I was still in non-macro-language land.
13:57	TimMc	I've been thinking about fancy whole-program stuff like type-inference.
13:59	amalloy	TimMc: if you've ever written (defmacro ...), then you were wrong when you said you're not the one writing clojure's compiler :)
14:01	TimMc	haha
14:21	hiredman	,(namespace 'foo/bar)
14:22	clojurebot	"foo"
15:07	brehaut	does anyone know if fogus's core.unify is in clojars?
15:08	rrc7cz	why might I still be getting a "WARNING: alias already refers to..." even though I have a (:refer-clojure :exclude [...]) in my ns?
15:18	kencausey	Well, I'm on day two of trying to download Brian Marick's robozzle.mov midge demo/tutorial from github with little progress. Again, has anyone a mirror by chance?
15:22	phenom_	hey anyone interested in helping me build out a queueing system? i'm doing it more to learn clojure than to compete in the market ... no standards or complexities, just a simple thing
15:22	odyssomay	kencausey, http://www.vimeo.com/19404746
15:22	Raynes	defn: Ping.
15:23	phenom_	anyone interested, get in touch with me ... github.com/djunforgetable
15:23	kencausey	odyssomay: Yeah, vimeo is a problem for me with screencasts because flash won't fullscreen for me and I see no option to popout a resizable window like I would with say youtube
15:24	kencausey	I have a dual-head setup which flash is not happy about
15:24	odyssomay	kencausey, so don't fullscreen?
15:24	kencausey	then it's too small to read
15:25	odyssomay	which flash version do you have?
15:25	kencausey	Linux 10.2 d161
15:25	kencausey	the problem may be with the nvidia driver
15:25	kencausey	some applications full screen fine, others don't, flash is not the only one that doesn't
15:28	odyssomay	kencausey, the flash is streamed to ~/.mozilla/firefox/*.default/Cache/
15:28	odyssomay	you can use mplayer or similar to view it
15:29	kencausey	odyssomay: cool, that's an idea, although for some reason today the flash viewer is not working at all, I see the default view but no option to start the video, the html5 player works though
15:30	kencausey	oh, except I'm not using moz ;) but the idea still holds merit
15:30	fliebel	brehaut: It's core.unify, so it ships with Clojure, right?
15:40	odyssomay	kencausey, If you happen to have flashblock, it doesn't work with vimeo
15:41	kencausey	I don't have any blocking of any kind
15:41	odyssomay	ok
15:41	kencausey	flash is working fine on other sites
15:41	kencausey	this is all rather irrelevant/off-topic at this point
15:42	odyssomay	yes, you're right, but it's pretty quiet here anyway
15:43	kencausey	sure
15:46	kencausey	Actually, this is all moot now, I find that vimeo's html5 viewer 'fullscreens' within the browser boundary (of course) so it works fine and hopefully the quality will be sufficient for my purposes
15:46	kencausey	but thanks odyssomay
15:47	kencausey	and then I can full-screen chrome and all is still good, enough about that ;)
15:47	odyssomay	heh, yeah np
16:40	rata_	hi
16:42	ohpauleez	Does anyone know how to select something with enlive that has a space in it
16:45	dnolen	ohpauleez: like a text node?
16:46	ohpauleez	dnolen: something like: (map html/text (html/select (scrape/fetch-url scrape/base-url) [:div.inner :ul.topiclist forums]))
16:46	ohpauleez	where the ul I'm going for is "topiclist forums"
16:46	dnolen	the className is topiclist-forums ?
16:47	dnolen	er I mean, 'topiclist forums'
16:48	brehaut	ohpauleez: in css, that is actually two classes
16:48	dnolen	:ul.topiclist.forums
16:48	dnolen	^ should work
16:48	ohpauleez	ahhh cool
16:48	ohpauleez	right tight
16:48	ohpauleez	thanks guys, I really need to focus
16:48	ohpauleez	:)
16:49	brehaut	dnolen: is the unifier in logos usable outside the context of your miniKanren imp?
16:51	dnolen	brehaut: it is, logos.unify/unifier and unifier'. It uses logos.minikanren under the hood, but it provides the same interface as fogus's core.unify
16:51	brehaut	dnolen: sweet :)
16:52	dnolen	brehaut: unifier takes prepped sexprs, that is sexprs where the location of the logic vars have already been determined. unifier' can take un-prepped sexprs, but its dog-slow cause of post-walk
16:52	brehaut	dnolen: im fine with dog slow ;)
16:53	brehaut	im writing a series of monkey and banana implementations (pg 46 of bratko)
16:53	brehaut	gradually moving from functional to logical
16:53	brehaut	i want to eventually end up with a logos implementation
16:54	dnolen	brehaut: nice! there's a pretty wacky critical bug I need to fix ASAP in logos, fingers crossed you don't run into it.
16:54	brehaut	hah cheers :)
16:54	brehaut	im still 2 steps away from the logos imp so hopefully i'll not run into it
17:02	lancepantz	does anyone know how keyword lookups are optimized on records?
17:02	lancepantz	are they converted to method calls at compile time or runtime?
17:02	brehaut	lancepantz: roughly i think? theres a callsite cache that does that
17:03	lancepantz	brehaut: so keywords are hashed and cached at runtime?
17:03	brehaut	i dont know if its hashed or what, but there is a runtime optimsation at the callsite
17:03	lancepantz	i've got a record lookup in an innerloop and my profiler says a lot of time is being spent hashing keywords
17:04	brehaut	beyond that i dont know any of the details
17:04	lancepantz	i had expected that to be converted to a method call at compile time
17:05	chouser	keyword lookups are compiled as method calls in case the target changes type
17:05	chouser	are NOT, :-P
17:06	lancepantz	i added a type hint expecting that to take care of it, didn't seem to change anything though
17:06	lancepantz	so if i want full optimization i should just call the methods using interop?
17:06	chouser	yes
17:06	lancepantz	great
17:06	lancepantz	thanks chouser :)
17:06	chouser	though I think the keyword should get hashed at compile time, so I'm not sure what you're seeing.
17:07	lancepantz	most of the activity is in clojure.lang.Keyword.hashCode
17:07	lancepantz	22% of my execution time
17:08	chouser	that method just returns a field of the keyword object
17:09	lancepantz	so that should be really fast?
17:09	chouser	one would think, yeah
17:10	lancepantz	my loop is calling it alot, i'm going to try interop and see if that helps
17:10	chouser	but regardless if you want maximum performance, use sufficiently hinted interop on the record.
17:10	lancepantz	cool
17:10	lancepantz	i'll report back :)
17:11	jkdufair	can i do interactive debugging in emacs?
17:12	jkdufair	found (i think) a bug in appengine-magic and want to step into it
17:14	raek	jkdufair: haven't tried this myself, but could be worth checking out: http://hugoduncan.org/post/2010/swank_clojure_gets_a_break_with_the_local_environment.xhtml
17:23	jkdufair	raek: thanks! i'll check it out
17:28	amalloy	jkdufair: see also george jahad's cdt
17:28	jkdufair	amalloy: super. thx!
17:59	rsenior	I'm hitting a snag with AOT compiling some code. I'm invoking multimethod (based on class) from inside a macro, during AOT compilation, it's treating the defrecord constructor as a list (i.e. (new-foo ...)). If I do not AOT compile, it's treating that same code as the defrecord type (Foo) instead of the persistent list, and it works fine.
18:00	rsenior	I'm trying to dig a little deeper to see if I'm hitting a bug or if it's just bad macro code, but I'm having difficulty figuring out what's different from AOT and the normal compile/load from the REPL
18:02	jweiss	this page seems to be out of date: http://clojure.org/protocols - probably just needs to reference to 1.2 being unreleased taken off. reason i bring this up is i'm trying to sell clojure to coworkers and this looks bad
18:03	rsenior	jweiss: send an email to alex@puredanger.com with that
18:03	jweiss	rsenior: ok will do, thanks
18:06	rata_	rsenior: have you a gist of that?
18:07	rata_	*with that code
18:07	rata_	macro I mean
18:08	rsenior	rata_: there's several, I could try to isolate it for a gist
18:08	rsenior	rata_: *there are several
18:08	rata_	give me one to look at the macro
18:11	rsenior	rata_: will do, one minute
18:11	brehaut	anyone here familiar with jim duey's state-t from c.c.monads ?
18:14	rsenior	rata_: https://gist.github.com/817497
18:17	rsenior	rata_: in that code snippit, record that is being destructured off of the first argument, is being interpreted as a list and the REPL as a record
18:18	amalloy	rsenior: this doesn't look to me like it should work
18:18	rsenior	rata_: not sure that tells you much
18:18	rata_	I think you want to eval the record constructor at compile time
18:19	rata_	why are you doing it with a macro?
18:20	amalloy	(record-matcher '(new-baz {:bar ?e})) is what your macro is doing at compile time (note the quote), and i don't see how it ever works at the repl
18:20	rsenior	that's a good question
18:21	rata_	what's record-matcher?
18:21	rsenior	record matcher is the multi-method that is being invoked based on type of record
18:22	rsenior	amalloy: I agree, not sure why it works at the REPL
18:23	rsenior	I stumbled on this today when I was switching a piece of previous not AOT compiled code to AOT
18:23	rsenior	ahh, now I remember why it needs to be a macro
18:24	rsenior	if-match is actually a macro in matchure (https://github.com/dcolthorp/matchure)
18:25	rsenior	(new-baz {:bar ?e}) has a symbol, ?e that the if-match macro is finding a replacing with a gensym'd symbol behind the scenes
18:25	rsenior	if the above code is a function, it will try and eval that ?e which will cause problems
18:26	rsenior	and is actually the error that happens at AOT compile time (and not at the REPL)
18:27	rata_	do you want to print those two lines at compile time?
18:27	rsenior	just for debugging
18:27	rata_	ok
18:27	rsenior	I put that there to try and find out what's going on
18:27	rsenior	and the (class record) part is what's returning a persistent list vs. a proper defrecord type
18:28	amalloy	rsenior: i don't really know what matchure tries to do, but you might find my article at http://hubpages.com/hub/Clojure-macro-writing-macros useful, regarding what should be a function and what should be a macro
18:33	rsenior	amalloy: nice entry, what solidified it for me was On Lisp, I found a lot of what was discussed relating to macros carried over pretty well to Clojure
18:34	amalloy	yeah, most of it applies pretty equally to any lisp
18:35	arohner	isn't there a built-in fn to convert a String to byte[]?
18:35	amalloy	&(.getBytes "test")
18:35	sexpbot	⟹ #<byte[] [B@1b220a3>
18:35	arohner	amalloy: thanks
18:35	amalloy	&(seq (.getBytes "test"))
18:35	sexpbot	⟹ (116 101 115 116)
18:36	amalloy	just checking :P
18:36	ninjudd	can type hints use an interface instead of a class?
18:37	arohner	ninjudd: I think so
18:37	amalloy	ninjudd: i don't see why not
18:37	amalloy	yeah, there are type-hints on j.u.Collection somewhere in core, i think
18:38	rata_	rsenior: when you remove those println, does it work?
18:39	amalloy	rata_: if that fixes it he should probably call an exorcist
18:41	rata_	hahahaha... the thing is, I don't see why the `(if-match ...) shouldn't work, he's unquoting everything in that expression
18:42	rata_	I suppose he's checked that (if-match [(record-matcher (new-baz {:bar ?e})) nil] (some ...)) works as he expects
18:42	amalloy	rata_: that's not what his code expands to
18:43	rata_	why not? what am I missing?
18:43	amalloy	i think he may actually mean `(if-match [(record-matcher ~record) ...])
18:43	rata_	yes... probably
18:43	amalloy	because he's trying to do the record-matcher call in the macro context instead of the expansion context
18:43	rata_	yes... that was what I was missing =P
18:47	amalloy	i don't know if that will fix his problem because he's trying to have compile-time access to the run-time information contained in (new-baz ...)
19:24	amalloy	argh, clojure has poisoned my mind. i find myself trying to implement lazy sequences for php just so i can generalize existing code
19:32	brehaut	amalloy: lol :)
19:32	brehaut	its when you start trying to write point free PHP that you know you have lost it
19:34	amalloy	brehaut: surely someone out there has written a haskell=>php compiler
19:34	amalloy	it's just such a natural combo of languages...
19:34	brehaut	haha
19:34	brehaut	one of the most academic languages wobbling along ontop of one of the least
20:17	phenom_	anyone else getting a small list for elpa package-list-packages command in emacs ?
20:35	amalloy	phenom_: i get 134
20:45	brehaut	has anybody used matchure?
20:45	TimMc	I AM A GOLDEN GOD
20:46	TimMc	ahem, sorry
20:46	amalloy	brehaut: rsenior was having trouble with it earlier, maybe send him a $mail?
20:46	TimMc	Just figured out the change of coordinates math for some graphics stuff.
20:46	brehaut	amalloy: cheers
20:47	TimMc	Anybody have recommendations for a matrix lib?
20:47	amalloy	TimMc: http://download.oracle.com/javase/1.4.2/docs/api/java/awt/geom/AffineTransform.html is probably useful?
20:48	TimMc	amalloy: Unfortunately, this is for a Computer Graphics homework assignment, and I think we're supposed to do the math ourselves on this one.
20:49	TimMc	amalloy: My breakthrough was in understanding the order in which all the component transforms need to happen.
20:52	TimMc	...but I really should ask the prof if I can use the Java2D math classes.
20:54	amalloy	TimMc: yeah, if you are going to use a matrix library, you might as well use the one designed for graphics, it seems to me
20:54	TimMc	True.
20:54	amalloy	and trust me, getting the order right will still matter with affinetransform :)
20:55	TimMc	indeed
20:55	amalloy	i vaguely remember similar issues when i was in college
20:55	TimMc	This is the first time I've needed to do anything more than flipping the y coordinates and translating the origin.
20:55	amalloy	ah. fitting to a window, i bet?
20:57	TimMc	Well, anything where I wanted standard (integer) Cartesian coordinates.
20:58	TimMc	Oh man, I remember writing stuff for my TI-89 graphing calculator... wrote a Mandelbrot fractal program that took 6 hours to run.
20:58	TimMc	ANyway.
20:59	amalloy	haha good old ti
20:59	amalloy	my early programs were for the 83
21:00	TimMc	I still have that 89. It's about 13 years old now.
21:01	TimMc	Maybe I'll write a Scheme interpreter for it some day. The parentheses are easy to reach on that keyboard.
21:19	pppaul	hey dudes
21:19	pppaul	i'm using lein, and i want to slurp a file: "file.txt" where should i put the file so (slurp "file.txt") works?
21:22	pppaul	got it
21:22	pppaul	thanks guys!
21:22	pppaul	:D
22:40	phenom_	how to you stop a cake swank server?
22:40	amalloy	cake kill
22:53	anthony__	The docs for the logging functions say that log4j is supported, and I'm able to get it to work when running my program from the REPL, but log4j doesn't seem to work after compiling with lein. Is there a better logging library, or am I doing something terribly wrong?
22:58	amalloy	anthony__: well, usually you shouldn't need to compile
22:59	amalloy	but you need log4j.properties in your classpath, which probably isn't making it into the jar
22:59	anthony__	amalloy: What's the recommended way of running clojure programs? I've always used lein jar (or uberjar).
22:59	foxupa	hello
23:00	anthony__	Yeah, I want it outside of my jar in case I need to change it. But it's in my pwd. I'll mess around with it some more.
23:00	amalloy	anthony__: i think lein run should work without compiling
23:00	amalloy	anthony__: your cwd isn't included in the classpath when running a jar
23:00	anthony__	amalloy: Oh, gotcha. You mean straight to "lein jar"?
23:00	amalloy	you probably want to add a resources directory
23:00	foxupa	I was wondering if anyone could show me how to redefine the eval function (I want to write metacircular evaluators)
23:01	amalloy	there's an entry in project.clj to specify directories to include straight in the jar
23:01	anthony__	amalloy: Gotcha. I was hoping to be able to run log4j.properties outside of the jar, so I could change it without re-packaging. But including it won't hurt. Thanks for the help.
23:02	scottj	foxupa: maybe call it something different?
23:02	amalloy	anthony__: you shouldn't need to package at all while you're developing
23:03	scottj	foxupa: there is some form I think you put in (ns) that will exclude stuff from clojure.core I think
23:04	anthony__	amalloy: Yeah, I'm not. Logging worked just fine during development. I'm packaging it up to send to a friend to use, and he might want his logging path to be somewhere different than mine. He's smart enough to change the file in the JAR, though, so no biggie.
23:04	amalloy	scottj: :refer-clojure
23:04	foxupa	well what I want is to be able to do (def eval [x] (eval (do (print x) x)))
23:04	foxupa	for example
23:04	foxupa	so that any call to the eval function prints out the argument
23:05	amalloy	foxupa: maybe robert.hooke?
23:05	amalloy	i haven't used it but that sounds like an appropriate tool
23:06	amalloy	i think it's one of technomancy's toys
23:07	foxupa	thanks amalloy, I think this will do the trick
23:08	foxupa	amalloy: although it is a bit dissappointing that this can't be done more naturally... is clojure.core somehow protected from redefinition?
23:08	scottj	waht about going into clojure.core and evaling (defn eval [form] (println form) (. clojure.lang.Compiler (eval form)))
23:09	foxupa	scottj, how do I go into clojure.core? Do I just some kind of (use-namespace clojure.core) call to step into it?
23:09	scottj	slime?
23:09	clojurebot	slime-install is an automated elisp install script at http://github.com/technomancy/emacs-starter-kit/blob/2b7678e9a331d243bf32cd8b591f826739dad2d9/starter-kit-lisp.el#-72
23:09	foxupa	scottj, sorry, I'm just giving Clojure a test drive coming from a scheme background
23:09	pdk	i think the idea is clojure.core is imported automatically at start
23:10	pdk	try doing say (doc print) or something
23:10	pdk	notice "clojure.core/print"
23:10	scottj	in slime ,clojure.core, in repl (ns clojure.core) I think, in code maybe (in-ns..
23:10	pdk	so it's auto :use-ing the names out of core
23:11	pdk	practical clojure has a chapter on namespaces and the funky handful of ways to import stuff
23:11	foxupa	scottj: awesome I got it to work... thanks a lot, I was scared for a bit that I wouldn't be able to do this (or have to go through some obscure hack to get it to work)
23:12	foxupa	scottj, I suppose now I can dive into clojure!
23:12	scottj	like a true schemer!
23:12	tomoj	can't wait until lamina's async works :D
23:12	scottj	(by fiddling with evaluators instead of "real" projects :)
23:12	technomancy	clojurebot: shut up man; that is a terrible link
23:12	clojurebot	'Sea, mhuise.
23:12	technomancy	clojurebot: forget slime-install
23:12	clojurebot	I don't understand.
23:12	technomancy	...
23:13	foxupa	scottj, the main pull was that clojure nearly quarters my scheme code base having elegantly implemented most of my machinery into the language
23:15	foxupa	scottj, just one last question but as clojure is a lisp, I really should be able to completely redefine whatever part of the language I want correct? or are there any subtle limits I should be aware of?
23:16	scottj	foxupa: I don't know but I'd guess there are some
23:16	headlessClown	no custom reader macros
23:16	scottj	headlessClown: easily anyway
23:59	no_mind	is there a way I can identify the datatype of a var ?