#clojure – 2008-10-12

2008-10-12

07:47	Lau_of_DK	Can somebody enlighten me on the syntax of Cond?
07:57	hoeck	Lau_of_DK: (cond condition1 expression1 conditionN expressionN ..)
07:58	Lau_of_DK	hoeck, yes, I realised that if one condition is true, other true values are ignored. That just surprised me. I was looking for something like (cond (> 2 1) ((do 1) (do 2) (do 3)) (> 2 0) ((do 1) ... (do n)))
08:02	hoeck	then use multiple ifs, cond is really just a replacement for else-nested ifs
08:03	Lau_of_DK	k
08:03	Lau_of_DK	Do we have something like (if (isin list1 list2)) that checks for replicates in either list?
08:05	hoeck	no, but we have sets, so just use (set/intersection (set list1) (set list2))
08:05	Pupeno	Is there a downloadable version of the documentationz
08:05	Pupeno	Z
08:06	Pupeno	?
08:06	Chouser	http://clojure.googlegroups.com/web/manual.pdf
08:12	Lau_of_DK	hoeck, first Im using a sequence of LazyCons with integer in it, secondly, my Clojure doesnt have set/intersection, that something new?
08:13	Pupeno	Chouser: how is that generated, do you know?
08:17	hoeck	Lau_of_DK: its the set.clj which comes with clojure and the correct name is clojure.set/intersection, sorry
08:18	hans	Pupeno: custom css, browser printing to acrobat. search the group archive, i posted the css
08:18	Lau_of_DK	no worries, I got it
08:52	Lau_of_DK	Is there an alternative to pop, which drops the first item in a list, but that does not throw an exception if its an empty list?
08:58	Chouser	"rest", depending on the data structure
08:59	Lau_of_DK	k, thanks
11:11	Fanda	hello all!
11:12	rhickey	hi
11:12	Fanda	i have couple questions
11:12	Fanda	one is about contributing
11:12	Fanda	how do you contribute to clojure-contrib?
11:12	Fanda	rhickey: I sent you a letter (agreement)
11:13	rhickey	who is Fanda?
11:13	Fanda	Frantisek Sodomka
11:14	Fanda	my usual way is to put code on my website:
11:14	Fanda	http://intricatevisions.com/index.cgi?page=clojure
11:14	rhickey	ok, I've got your CA
11:14	Fanda	good :-)
11:15	Fanda	my question is, how code gets into clojure-contrib
11:15	rhickey	first step would be to submit patches for contrib on the Clojure group, the contrib owners will include them if they fit in
11:15	rhickey	After I get a feel for your contributions I might make you a developer on the SF contrib project
11:16	rhickey	if you have a whole new lib for contrib, again post to group, I'll look at it and decide
11:16	Fanda	ok, i see
11:16	Fanda	i like to contribute anything that I find useful for myself
11:16	rhickey	what did you want to contribute?
11:18	Fanda	just a second, i will find it...
11:18	Fanda	http://groups.google.com/group/clojure/browse_frm/thread/d15f190f09c0eead/bb705e2e2d897349?lnk=gst&q=aspect#bb705e2e2d897349
11:19	Fanda	"code sections", which were rewritten Stephen C. Gilardi as "aspects"
11:20	Fanda	i would put it into some 'util' namespace
11:20	Fanda	similar goes for http://groups.google.com/group/clojure/browse_frm/thread/d7e82974b2b58d0a/b8f1d7adeba0dfda?lnk=gst&q=time-expr#b8f1d7adeba0dfda
11:21	rhickey	ok, I remember, sorry I didn't chime in then. Are you familiar with CL #+ and #- ?
11:21	Fanda	no, I don't really have experience with CL
11:21	Fanda	what #+ and #- do?
11:23	rhickey	http://www.lispworks.com/documentation/HyperSpec/Body/02_dhq.htm
11:23	rhickey	http://www.lispworks.com/documentation/HyperSpec/Body/24_abaa.htm
11:27	rhickey	better: http://www.lispworks.com/documentation/HyperSpec/Body/24_aba.htm
11:29	Fanda	yes, (aspect :debug (do-something)) would be (do #+debug (do-something))
11:30	rhickey	a big difference is #+/- are reader macros that conditionally read
11:32	Fanda_	sorry, my connection isn't too stable
11:32	Fanda_	my last sentence was "since # is special for Clojure, it would need to be implemented in the core, right?"
11:33	rhickey	yes, reader macros have to go in LispReader
11:34	Fanda_	it is just a suggestion... i like both versions
11:34	Fanda_	i am sure that I will just it when developing, since it is a common pattern
11:34	rhickey	something like #+ will end up in Clojure
11:37	Fanda_	can (do #+debug (do-something)) be somehow rewritten without 'do'?
11:37	Fanda_	(#+debug (do-something)) ???
11:38	rhickey	#+ turns into whitespace if false
11:39	Fanda_	so #+debug (do-something) would be fine
11:39	rhickey	would just disappear if not debug
11:40	Fanda_	yeah, sounds good
11:40	Fanda_	sometimes i need to define different levels of debugging - debug-calculation, debug-writing-to-file, debug-ui, ...
11:41	Fanda_	or logging - log-xyz, ...
11:41	Fanda_	... so that's where it started :-)
11:42	rhickey	logging is different - vars help there
11:42	rhickey	(binding [log-level :verbose] ...)
11:43	Fanda_	oh, i see
11:43	Fanda_	that makes sence
11:43	Fanda_	sense
11:43	kotarak	If I understand correctly, this is compile time. So it's like good olde #ifdef?
11:44	Fanda_	yes, exactly
11:44	rhickey	read-time
11:44	rhickey	compiler never sees it
11:44	kotarak	Ok.
11:44	Fanda_	preprocessor-time :-)
11:45	kotarak	as in C. #ifdef is also not seen by the compiler.
11:46	Fanda_	.......
11:46	Fanda_	other thing - compiler now has warn-on-reflection, right?
11:46	Fanda_	i would put it into map
11:46	Fanda_	something like compiler-settings
11:47	Fanda_	and do (def compiler-settings {:warn-on-reflection true})
11:47	Fanda_	so that we can easily add more compiler options later...
11:48	kotarak	I'm not sure, I like this #+ thing....
11:49	Fanda_	syntax of it or the behavior (semantics)?
11:49	Fanda_	(still here)
11:49	kotarak	the behaviour
11:51	Fanda_	what don't you like? i find it very useful
11:53	kotarak	If there something, that can be done with it, which cannot be done with "normal" macros?
11:53	kotarak	/If/Is/
11:53	Fanda_	it is up to Rich - if he wants it in the core or not
11:53	Fanda_	i am ok with macro
11:54	kotarak	I didn't say it shouldn't go to Clojure core. I don't have to use it after all. It is up to Rich.
11:57	Fanda_	ok
11:57	Fanda_	other thing: should boot.clj be renamed to clojure.clj??? since it is a 'clojure' namespace? :-)
11:58	rhickey	kotarak: normal macros can't disappear
11:58	rhickey	Fanda_: will rename soon
11:58	Fanda_	:-)
11:58	Fanda_	and what about testing Clojure?
11:59	Fanda_	i would create some test-clojure.clj, test-set.clj, ...
11:59	Fanda_	to test its correctness
11:59	rhickey	Fanda_: go for it!
11:59	kotarak	rhickey: I see stuff like (if (something) #+ (x) (y)) and people asking, why does my code not work? A macro can always expand to nil...
12:00	Fanda_	rhickey: I actually might - it would be a nice exercise
12:00	Fanda_	rhickey: once it gets started, other people will join and it can be done very quickly
12:02	rhickey	kotarak: in source, nil is not the same as whitespace
12:05	duck1123	what does it mean if I get an InvocationTargetException when trying to construct an object?
12:07	kotarak	rhickey: I still don't get the use. It's like old #ifdef. I don't see why I would that.
12:08	rhickey	duck1123: do you have an example?
12:10	lisppaste8	duck1123 pasted "exception when creating object" at http://paste.lisp.org/display/68368
12:11	Fanda_	kotarak: look in thread http://groups.google.com/group/clojure/browse_frm/thread/ce795dd1fb646df1/d1c6c3b3f6485ece
12:11	Fanda_	kotarak: download http://groups.google.com/group/clojure/attach/394c5334d6d7e2a1/cfa.clj.zip?part=4
12:11	Fanda_	kotarak: see lines like ;(println (list r g b a));;;;DEBUG
12:12	Fanda_	;(try
12:12	Fanda_	; (println (list 'push cnt (.. Thread (currentThread) (getName))))
12:12	Fanda_	; (println stack)
12:12	Fanda_	;(catch Exception e (println (list 'exception at c cnt))))
12:13	rhickey	duck1123: you might be missing other needed jars - also try putting them in your real classpath vs add-classpath
12:13	Fanda_	kotarak: all these lines could be put into #+debug (do ...)
12:14	Fanda_	kotarak: #+test (do ...)
12:15	Fanda_	rhickey: where does symbol for #+ come from? is it from global namespace? it might cause symbol pollution...
12:15	Fanda_	rhickey: aspect macro has (def +aspects+ #{:debug :log0 :log1}) which looks better to me
12:17	kotarak	Fanda_: And all these lines can be put into macro which conditionally evaluates to nil at compile-time.... But have to go now. Bye.
12:17	rhickey	CL isn't perfect, but you need to fully understand it before you attempt to better it
12:18	Fanda_	bye, kotarak
12:19	Fanda_	rhickey: Yeah, no offense. I have no clue about CL.
12:19	rhickey	more to kotarak's point, there are cases where generating nil is insufficient
12:20	Fanda_	yes, I believe in that
12:20	rhickey	#+it-takes-another-arg that-arg
12:22	Fanda_	could you elaborate more, please?
12:24	karmazilla	is there a literal syntax for BigIntegers, like 3M is a BigDecimal?
12:24	rhickey	#+ can deal with platform differences, API versions etc. Imagine an api has added an argument in a new version. Code that needs to work with both version needs to supply that arg only if it is the new version, if not, it can't pass nil
12:26	rhickey	karmazilla: no - you want to create a small BigInteger?
12:27	karmazilla	well.... yes. it just happens to be the only class that have the isProbablyPrime method, that I need for a project euler problem
12:28	Fanda_	rhickey: i am still wondering about grouping symbols for #+
12:28	Fanda_	rhickey: maybe just put it into namespace!
12:29	Fanda_	rhickey: reader-options/it-takes-another-arg
12:29	rhickey	karmazilla: (BigInteger/valueOf 123)
12:32	Fanda_	rhickey: after all - symbols for #+ will be automatically only in the namespace, where I write the code, so I will create symbols only in certain namespaces
12:32	Fanda_	rhickey: good enough
12:35	Fanda_	thanks for chatting all!
12:35	Fanda_	have to go
12:53	achim_p_	hi everyone
12:53	achim_p_	rhickey: i like the new #= reader macro and print emitting constructor calls.
12:54	achim_p_	i assume there's no easy way to determine whether a java class can take its toString representation as a ctor arg and make sense out of it, or is there?
12:55	kotarak	back with a problem: did anyone experience problems with gen-interface? The .class file is generated and in the classpath, but using/importing the interface throws a NoClassDefFoundError: <vector: - 1 items>.
12:55	rhickey	achim_p_: there isn't, but the default presumes that might work
12:56	duck1123	is proxy what I need to be using if I need to create a new class to pass to a function? (like this http://jena.sourceforge.net/ARP/standalone.html#sample)
12:57	danlarkin	duck1123: proxy creates an instance of a class
12:57	achim_p_	rhickey: on my machine a printed j.u.Date won't read for some reason, while it appears to work for other people - did you consider falling back to java's serialization for java classes without dedicated print method?
12:58	achim_p_	sth like (RT/resurrect \? \? \
12:58	achim_p_	it doesn't look humane at all, but might make serialization via print more generally applicable ...
12:58	rhickey	achim_p_: how does a date print for you?
12:59	rhickey	achim_p_: I'd really prefer text serialization
12:59	achim_p_	like that: #=(java.util.Date. "Sun Oct 12 18:56:32 CEST 2008")
12:59	achim_p_	localization issues, i assume
13:00	rhickey	achim_p_: that's really lame
13:01	rhickey	well, it may end up that Date needs a print-method
13:01	achim_p_	but it might end up that lots of classes need a print method ;)
13:02	rhickey	achim_p_: that's true
13:09	Chouser	kotarak: how are you trying to use gen-interface?
13:12	kotarak	Chouser: I did (gen-and-save-interface "some-dir" 'full.qualified.Name ['bla [] Object] ['blub [] Object]). It generated a class file.
13:12	kotarak	Then using the interface somehow fails, although the file is in the classpath.
13:15	Chouser	using it in what way?
13:16	kotarak	(proxy [Name] [] ....) , or via import. Neither works (it blows the import, or later on the proxy, when using a fully qualified name)
13:16	Chouser	hm...
13:20	Chouser	ok, I'm seeing that, but I don't understand -- I can use introspection on the interface
13:23	kotarak	Shall I try something on my side?
13:26	Chouser	no, I've got proxy failing for me here, I just don't understand how, since the introspection works.
13:27	kotarak	ok
13:36	achim_p_	lisppaste8: url
13:36	lisppaste8	To use the lisppaste bot, visit http://paste.lisp.org/new/clojure and enter your paste.
13:37	lisppaste8	achim_p pasted "printing dates" at http://paste.lisp.org/display/68377
13:37	Lau_of_DK	I'm working on a (supposedly) simple decimal expansion routine, that would expand something like 1/7 to 1.142857. It should expand further than that because the sequence then repeats itself, and it should not expand to anything shorter, because that would be inaccurate. Does anybody here have a few minutes to help out?
13:41	achim_p_	Lau_of_DK: (double 1/7)?
13:42	Lau_of_DK	And you can see, that expands further than I need
13:42	Lau_of_DK	I need it to stop as soon as the infinite cycle has been identified
13:42	Lau_of_DK	Here's a couple of ideas on how to attack it: http://www.bestinclass.dk/download/fraction.clj
13:42	Lau_of_DK	sadly, neither work, thought I think option #2 is closer to working
13:44	Lau_of_DK	(just updated)
14:05	Chouser	kotarak left.
14:06	achim_p_	Lau_of_DK: mmh, what's your strategy here?
14:06	achim_p_	i'd first try to obtain a sequence of the digits and then run some cycle-detection algo on it
14:07	Lau_of_DK	strategy is this. if x > a, then a*10 goes into recursion. if not, then the first digit of (x / a) is the next digit in my result, and (rem a x) goes into recursion. This breaks when (rem a x) gives a result, which has already been given once before
14:07	Lau_of_DK	achim_p, that not possible, sometimes I will need to dig deeper than 600 digits
14:09	duck1123	aren't all iterators seq-able?
14:09	duck1123	if not, how would I get a seq from one
14:10	Chouser	duck1123: (seq iterator) ?
14:11	duck1123	Don't know how to create ISeq from: StmtIteratorImpl
14:11	Chouser	what's a StmtIteratorImpl?
14:12	duck1123	don't know about the impl part, but http://jena.sourceforge.net/javadoc/com/hp/hpl/jena/rdf/model/StmtIterator.html
14:13	duck1123	got it from this http://jena.sourceforge.net/javadoc/com/hp/hpl/jena/rdf/model/Model.html#listStatements()
14:18	Chouser	Hm, seq need it to be Iterable, and oddly Iterator is not?
14:18	rhickey	duck1123: (iterator-seq iter)
14:20	duck1123	that works
14:21	gnuvince_	rhickey: do the profits for the "State: you're doing it wrong" t-shirt go to you?
14:22	achim_p_	Lau_of_DK: i might be a bit slow on the uptake atm, but what's the idea behind this approach?
14:23	Lau_of_DK	No nothing special, its just imo the simplest approach to computing all the decimals of a decimal expansion, one by one
14:23	achim_p_	i'd suggest floyd's cycle detection on the sequence of digits, which you can generate as you go
14:23	rhickey	gnuvince_: what shirt?
14:24	achim_p_	it's a one pass thing, so it should be reasonably fast
14:24	achim_p_	Lau_of_DK: http://en.wikipedia.org/wiki/Cycle_detection
14:24	gnuvince_	http://www.zazzle.com/state_youre_doing_it_wrong_black_shirt-235150036182618712
14:24	Chouser	gnuvince_: the zazzle clojure account is mine currently, and I have so far spent every penny
14:24	Chouser	...of the $0 it has raised.
14:25	gnuvince_	ok
14:25	Lau_of_DK	achim_p_, but its still overkill. If you take the first solution I posted, the bulky one, then it actually generates the sequence justs as its supposed to. All I need to implement is something that abort the whole show, if (rem a x) equals something thats already in list 'modulus'
14:25	gnuvince_	Chouser: upvote to get more views: http://www.reddit.com/r/programming/comments/76p6s/clojure_tshirt_state_youre_doing_it_wrong/
14:25	Chouser	gnuvince_: The profits will be passed along to Rich.
14:29	anyn	hi
14:31	anyn	I'm a newb, so I'm looking for some basic help. I'm playing around with the java-gnome bindings and, when utilizing Gtk, one must first 'initialize' gtk. In the java-gnome examples, they do this:
14:31	anyn	public static void main(String[] args) { Gtk.init(args); ...
14:31	achim_p_	Lau_of_DK: modulus contains digits, right? how do you handle recurring sequences like 12131213?
14:32	anyn	I'm guessing that, in those examples (I've ran them), args is just an empty String Array
14:32	Lau_of_DK	I handle them individually. The solution would probably lie in making this work according to my will (= true (some #(= % last) (rest modulus))) and it almost works
14:33	Lau_of_DK	user=> (fraction 7.0)
14:33	Lau_of_DK	(1 4 2 8 5 7 1 4 2 8 5 7)
14:33	Lau_of_DK	this is a good expansion, it just runs twice as long as its supposed to
14:34	Lau_of_DK	the corresponding sequence of modulus is
14:34	Lau_of_DK	(fraction 7.0)
14:34	Lau_of_DK	(3 2 6 4 5 1 3 2 6 4)
14:34	Lau_of_DK	and at the 2.nd '3', it was supposed to break, that would have given the correct result
14:34	anyn	and the trouble I'm having is in feeding an empty String Array into init
14:35	gnuvince_	Did you guys get a chance to read my first blog post on Clojure? http://www.reddit.com/r/programming/comments/76ofb/cribbage_points_counter_in_clojure/
14:37	anyn	gnuvince_: talking to me?
14:37	Chouser	anyn: (make-array String 0) is a zero-length array of String
14:38	anyn	Chouser: ah, ok.. I was trying (make-array String 1) and it crashed the gui-Repl :)
14:38	Chouser	that would be the right type, but with a null that apparently made gtk mad.
14:39	gnuvince_	anyn: I was asking in general. I'd like to get feedback for that code.
14:39	gnuvince_	(especially the count-straight function which makes me cringe)
14:41	achim_p_	Lau_of_DK: (fraction 7.0) returns about 500 digits for me
14:41	Lau_of_DK	yes, but notice the commented out line in the beginning of the lop
14:41	Lau_of_DK	(cond (or (> count 10)
14:41	Lau_of_DK	(= true (some #(= % last) (rest modulus))))
14:41	Lau_of_DK	if you use this as the circuit-breaker, then you'll only get a few
14:45	Lau_of_DK	According to my head, this:
14:45	Lau_of_DK	(= true (some #(= % last) (rest modulus)))
14:45	anyn	Chouser: that worked
14:45	Lau_of_DK	means, if the value of the var "last" is found anywhere in "modulus" except for the first value, then break, right?
14:57	Lau_of_DK	Maybe I'm imaging, but doesn't clojure have something along the lines of (but-last list)
14:57	Lau_of_DK	something that gives me everything, except the last item, and does not throw exceptions
14:58	fyuryu	Lau_of_DK: butlast
14:58	Lau_of_DK	great
14:58	Lau_of_DK	exactly what I needed.
14:59	Lau_of_DK	achim_p_, stand down, and thanks alot for looking into it, its working now
14:59	duck1123	fyuryu: is that lazy?
15:00	achim_p_	Lau_of_DK: cool. i hate number theory, but at least now i understand that why you're safe to assume that each element in the sequence of recurring digits is unique. :)
15:01	Lau_of_DK	oh, I sent you out on a mathematical hike?
15:02	achim_p_	correction: each remainder must be unique. yeah, enough hiking for today.
15:02	fyuryu	duck1123: no
15:03	Lau_of_DK	user=> (fraction 7.0)
15:03	Lau_of_DK	"1.1428571"
15:03	Lau_of_DK	user=> (/ 1 7.0)
15:03	Lau_of_DK	0.14285714285714285
15:03	Lau_of_DK	argh, correction
15:04	Lau_of_DK	user=> (fraction 7.0)
15:04	Lau_of_DK	"0.1428571"
15:04	Lau_of_DK	user=> (/ 1 7.0)
15:04	Lau_of_DK	0.14285714285714285
15:04	Lau_of_DK	there, now fraction yields the infinite sequence, which is accurate
15:19	anyn	Trying to tie some events into the gui here, in java-gnome bindings. How they do it, as they describe, "you need to hook up a "signal handler" to deal with the 'clicked' signal" ... "Button.Clicked is a Java interface. You create an instance of it to do what you want when the callback happens, and thenn pass it to the Button's connect() method."
15:19	anyn	http://java-gnome.sourceforge.net/4.0/doc/examples/button/ExamplePressMe.html
15:20	anyn	So, I'm trying to figure out how to translate that into clojure
15:20	anyn	I've got something like...
15:21	anyn	(.connect b (Button. Clicked ... hmm
15:21	anyn	or would it be (.connect b (.Clicked Button.
15:22	rhickey	Button$Clicked
15:22	anyn	and then I need to implement the method, as would be done inside java's {}, after the new Button.Clicked()
15:22	anyn	rhickey: $? is that new?
15:22	rhickey	anyn: no, that's the JVM name for a nested class
15:23	rhickey	then you'll need to use proxy
15:23	rhickey	http://clojure.org/jvm_hosted
15:23	anyn	ok, something analogous to the celcius example
15:25	Lau_of_DK	anyn, I got this from blackdog, it makes things easier:
15:25	Lau_of_DK	(defmacro onClick [obj & body]
15:25	Lau_of_DK	`(. ~obj addActionListener
15:25	Lau_of_DK	(proxy [ActionListener] []
15:25	Lau_of_DK	(~'actionPerformed [evt#]
15:25	Lau_of_DK	~@body))))
15:28	anyn	Lau_of_DK: I'm not quite there yet. still learning defs.. but once I get the hang of it, I'll try to use that.. I'm using the java-gnome binginds too
15:29	Lau_of_DK	k
15:36	anyn	in "new Button.Clicked()" .. is Clicked() a regular method or a constructor for a class called DeleteEvent? Trying to use proxy.. would I use (.connect b (proxy [Button$Clicked] (onClicked [source] (print "clicked")))) ?
15:36	anyn	or (proxy [Button] [Clicked] (onClicked ...
15:37	anyn	or (proxy [.Clicked Button] (onClicked
15:39	rhickey	(proxy [Button$Clicked] [] (onClicked ...
15:41	anyn	ok, I'll give that a shot
15:48	anyn	Unable to resolve symbol: Button$Clicked in this context
15:49	anyn	i'm running a fairly recent version of clojure
15:53	hoeck	anyn: have you imported Button$Clicked?
15:54	hoeck	anyn: or does `Button' on the repl eval to sth useful?
15:57	anyn	hmm. the java version doesn't import it.. but I'll try
15:57	rhickey	anyn: you need to import it
15:58	anyn	ah.. my bad.. I've never noticed that $ usage yet in clojure
16:03	anyn	it's working slightly
16:08	lisppaste8	karmazilla pasted "partial reduce patch?" at http://paste.lisp.org/display/68385
16:11	rhickey	karmazilla: interesting, but begs the question about currying map, filter etc similarly
16:12	karmazilla	yes it does... should I?
16:12	rhickey	not right now, let me think about it
16:13	Hun	one could also add autocurrying for 2+-adic functions.. not sure if it fits in the picture though
16:13	rhickey	that sort of currying is not idiomatic Clojure - people don't expect those functions to return fns
16:14	rhickey	but many of the fns are set up for partial application, and could curry
16:15	rhickey	could you post on the group so we can get some feedback from more users?
16:15	karmazilla	sure
16:15	achim_p_	what's the recommended way of providing a print-method for something that already has one (Class, in this case)? switching to the clojure ns and redefining feels wrong.
16:16	rhickey	achim_p_: why do you want to do that?
16:24	achim_p_	rhickey: hm, you're right, it hardly makes sense. different print behaviour (with serialization) is probably better implemented separately
16:24	rhickey	achim_p_: you can always build your own multimethod where the default calls print-method
16:25	gnuvince_	rhickey: are you considering adding currying to clojure?
16:26	rhickey	gnuvince_: no, karmazilla was suggesting some fns like reduce could curry themselves
16:27	gnuvince_	OK
16:28	gnuvince_	Not sure that currying is very "Lispy"
16:28	rhickey	I agree
16:29	rhickey	currying is a dubious shorthand, because it requires reader of code to know the arity in order to distinguish a curry from a call
16:30	karmazilla	I suppose it is kind of foreign to any language that allow callables to have more than one signature
16:31	rhickey	it's also weak in being arg-order dependent, thus flip etc
16:31	gnuvince_	I really like Haskell, but sometimes I think that currying makes some code harder to grasp than it would be otherwise
16:31	rhickey	exactly +1 for write, -1 for reader
16:31	gnuvince_	Especially when people go crazy with currying and function composition.
16:31	rhickey	writer
16:32	rhickey	I like Clojure's #(), can replace any arg or args easily, stands out that you are doing a partial application and returning a fn
16:32	rhickey	and fairly concise
16:32	karmazilla	haskell takes the consept to the extreme. I'm only suggesting this for a select few functions
16:34	rhickey	karmazilla: I understand, and I think if it was very uniform in the libs, i.e. every fn that takes a fn + args can be curried given fn, then maybe
16:35	rhickey	otoh I don't want people to presume there is general currying
16:40	karmazilla	man, language design is hard :)
16:40	gnuvince_	It is
16:42	anyn	when I run (.main Gtk), the repl hangs until I close the gui. I'd like to be able to interactively change the gui while it's running. How does one do that?
16:42	rhickey	anyn: can you run the GUI in another thread?
16:45	anyn	yea, would I use a ref or an agent?
16:46	rhickey	an agent
16:46	rhickey	or just Thread
16:46	rhickey	Clojure fns are Runnable
16:47	anyn	k
16:49	karmazilla	that reminds me, BGGA closures can do this trick with single-method interfaces. Can Clojure do that too?
16:50	Chouser	gnuvince_: "for" can walk over more than seq, in which case they act like they're nested. "powerset" could be written with a single "for"
16:50	rhickey	karmazilla: no sugar for that yet
17:03	lisppaste8	achim_p_ pasted "patch: ctor exceptions with class names" at http://paste.lisp.org/display/68389
17:04	rhickey	achim_p_: please post patches to group - I can't take patches from pastes, thanks
17:35	rhickey	rev 1065 has first steps toward AOT compilation - constants now read from strings in classfiles vs. hand-off from classloader, looking for testers
18:02	karmazilla	it ain't much but my four project euler scripts all seem to work with 1065 :p
18:05	rhickey	karmazilla: thanks, I expect most normal stuff to work, but macros that emit tricky constant values might need some print-methods
18:24	achim_p_	rhickey: ok, i thought such a minor change wasn't worth bothering the mailing list, but i understand there are probably license issues. i just posted it.
18:30	mhinchey	rhickey: slime fails to start with svn 1065
18:53	achim_p_	require seems broken
18:54	achim_p_	when requiring a file that's empty except for a namespace declaration, an exception is thrown: java.lang.ExceptionInInitializerError (NO_SOURCE_FILE:0)
18:54	achim_p_	Caused by: java.lang.IllegalStateException: var: clojure/loaded-libs is not public
19:15	cads	hello
19:16	cads	I just watched the clojure video I was impressed
19:18	cads	I've been reading about concurrency and wanting to try it... also been interested in lisp
19:19	cads	now I read about clojure and it's very interesting as a lisp with powerful concurrency primitives
19:20	cads	but I don't know whether it will be too hard for me to learn with my schedule
19:21	cads	there is another concurrency-strong language that I've been thinking about, and that is erlang
19:22	cads	and I was wondering if I could get your opinions about which of the languages would be more approachable for someone with limited background in writing concurrent code
19:26	cads	one thing I was wondering about is whether clojure being a lisp makes learning it particularly difficut
19:34	gnuvince_	cads: depends on your background.
19:50	rhickey	mhinchey: what's the error from slime with svn 1065?
19:51	mhinchey	user=> java.lang.ExceptionInInitializerError (core.clj:0)
19:51	mhinchey	user=> java.lang.Exception: No such var: swank/ignore-protocol-version (NO_SOURCE_FILE:5)
19:51	mhinchey	user=> java.lang.Exception: No such var: swank/start-server (NO_SOURCE_FILE:7)
19:53	mhinchey	that's probably not too helpful. I'll try to debug it more to find out.
19:53	cads	I've mostly played around in ruby haskell, in ruby where I loved the friendliness but it didn't seem like it would be simple to do concurrency, and I wanted to be able to redefine some syntax and could not, and in haskell where I loved recursion and the power of algebraic datatypes but where again the level of abstraction needed to do concurrency was too complicated for me to do on my own right away.
19:53	achim_p_	rhickey: a (require 'anything) triggers a Compiler.resolveIn(current-ns, clojure/loaded-libs), which fails because it's not public.
19:54	achim_p_	that didn't happen in r1064
19:55	achim_p_	i think that's the same problem mhinchey describes
19:57	mhinchey	yes, same thing
20:12	arbscht	cads: that clojure is a lisp does not make it especially difficult
20:17	spacebat_	cads: erlang is hell bent on concurrency, while other aspects of the language leave much to be desired
20:17	spacebat_	but its process based concurrency not threading yes?
20:18	spacebat_	I think clojure has much more sound fundamentals, flexibility of expression with easy and correct thread based concurrency
20:19	spacebat_	and someday it will probably have the multiprocess/multiserver concurrency of erlang via some library or other
20:48	rhickey	mhinchey: looking at it now, thanks
21:00	rhickey	rev 1066 should help with require error
21:19	cads	thanks for the input you guys
21:20	rhickey	cads: did you get any? I was of for an hour
21:20	rhickey	off
21:24	mhinchey	rhickey: thanks, slime starts now
21:25	rhickey	mhinchey: great!
21:34	cads	rhickey, yeah, I'm going to go ahead and try messing around with it
21:35	cads	I think I'll miss the smalltalk-esque encapsulation and object oriented rapid prototyping from ruby, at least till I learn the idioms
21:36	cads	put to get to use java's libraries for graphics and what have you... without having to touch java... seems like a big plus
21:37	rhickey	cads: you should find a lot of people from similar backgrounds both here and on the group to help out with the paradigm shifts
21:38	Chouser	ruby was my favorite language to play in before Clojure.
21:38	rhickey	Chouser: do you miss he OO?
21:38	rhickey	the
21:39	Chouser	haven't yet.
21:39	Chouser	I fumble a bit with design questions
21:40	Chouser	as in, I knew OO well enough that most problems have "obvious" design solutions for me
21:42	Chouser	I'm not there yet with Clojure -- I'm afraid I'm making poor choices of when to use a multimethod, how to structure my data, etc.
21:43	Chouser	In practice, the couple times I've chosen poorly, the "refactoring" has been pretty shallow and easy to deal with.
21:46	rhickey	I had become so tired of "new class per idea", had already gotten used to using generic data structures even when in C#/Java
21:47	cads	ruby seems to make it a bit less painless than java
21:48	Chouser	hm, I was not tired of "new class per idea" in ruby. I saw that as an upgrade from the generic data structures of perl.
21:48	rhickey	heh
21:48	rhickey	so isn't Clojure similar in that way?
21:49	Chouser	I loved the ruby generator/iterator stuff, but of course that's a sort of weak echo of macros.
21:50	cads	I've been wondering if that isn't that case, too
21:51	cads	rubyists seem extremely averse to any kind of macro system
21:52	Chouser	that's an interesting point. hadn't thought of it that way. Maybe the difference is that I thought I was supposed to be using objects.
21:53	cads	even though ruby it pretty good at defining a domain specific language using its block closures, sometimes the syntax is unwieldly and I wish I could just define a construct
21:53	Chouser	perl didn't have multimethods and multi-taxonomy inheritence to help manage the generic data structures.
21:54	mhinchey	rhichey: 1066 causes this exception in my code, still trying to track down the cause: Caused by: java.lang.IllegalArgumentException: No matching ctor found for class clojure.lang.Namespace at clojure.lang.Reflector.invokeConstructor(Reflector.java:136)
21:54	rhickey	mhinchey: do you have a macro that embeds a namespace object in the expansion?
21:55	mhinchey	yes
21:55	rhickey	that's it
21:56	cads	chouser, was clojure your first introduction to a lisp?
21:56	rhickey	mhinchey: you can try defining a print-method for Namspace that prints to a #= call to Namespace/find
21:57	rhickey	back in a bit
21:57	Chouser	cads: I had made a couple solid runs at CL, but never got comfortable with the parens, and felt betrayed by the lackluster libraries.
22:00	Chouser	Since much of my "fun" little programs need to plug into other things -- web site, files, directories, GUI toolkits -- I felt like CL was supposed to be this great powerful thing, but it was lots of work to do anything useful.
23:00	rhickey	mhinchey: I've added a print-method for namespaces, svn rev 1067
23:00	mhinchey	thanks, I'll check it later
23:06	spacebat_	I've learned a bit of CLOS now, and I wonder if anything like that exists in clojure
23:07	spacebat_	or do we just have structs and generic methods, and leave the OOP to java
23:08	rhickey	Clojure has multimethods and ad hoc hierarchies and metadata
23:08	rhickey	mix and match to make as much OO as the problem requires
23:08	spacebat_	type hierarchies, like structs that inherit?
23:08	anyn	gtk wants to return a zero at the end of a method. How do I do that?
23:08	rhickey	(derive :square :rect)
23:08	spacebat_	ok
23:08	spacebat_	that sounds sane
23:09	anyn	erm, I mean false
23:09	rhickey	user=> (derive ::square ::rect)
23:09	rhickey	nil
23:09	rhickey	user=> (isa? ::square ::rect)
23:09	rhickey	true
23:09	anyn	"return false)
23:09	anyn	s/)/"
23:09	Chouser	anyn: (fn [] ..... (false))
23:09	Chouser	gah
23:09	rhickey	so you can use ns-qualified keywords as 'types', but put them in map attributes, metadata etc
23:10	Chouser	anyn: (fn [] ..... false)
23:10	anyn	ah, ok
23:10	spacebat	rhickey: I noticed a bunch of projects like dotLisp and foil that you've involved with, are they live/active or more like stepping stones on your way to clojure?
23:10	anyn	perfect
23:11	rhickey	spacebat: you can also 'derive' Java classes from keywords, to superimpose additional taxonomies on classes you didn't write
23:11	rhickey	spacebat: jFli has seen some enhancement from Nick Levine, the others are static
23:12	rhickey	Clojure goes way beyond what they could do
23:12	spacebat	ok, yeah I thought if they were live and you were involved, you'd be unspeakably busy
23:12	spacebat	so there's a clojure book out from pragmatic programmers next march or so?
23:13	spacebat	I'll have to start reading the docs again, after playing with CL a few months I think things will make more sense
23:14	rhickey	spacebat: they work, but one thing I learned was that very very few CL people care about Java integration, yet Clojure proves many people care about Lisp + JVM and the other things Clojure addresses
23:15	spacebat	well I like CL, and I have some hopes that Armed Bear CL will get there in the end
23:16	spacebat	but I know that lisp needs a single modern implementation to focus on, and clojure might just be it
23:16	spacebat	s/implementation/dialect/
23:17	rhickey	I'm on a 'Next 50 Years of Lisp' panel at OOPSLA - should be interesting
23:17	spacebat	sweet
23:17	spacebat	a bit more conservative than the idea of a '100 year language' like arc
23:18	spacebat	I want to believe arc is significant, but I've yet to grok what's so good about it
23:18	spacebat	been playing with ECL, librep and picolisp the last little while
23:19	spacebat	both librep and picolisp are mentioned as pre-arc arcs by some people
23:19	Chouser	I used a window manager for a long time that was largely written in librep
23:19	spacebat	picolisp is probably the most radical, purely interpreted, functions can mutate their own forms at runtime etc
23:20	gnuvince_	rhickey: what's that panel gonna address? Multi-core programming?
23:20	spacebat	sawfish, yes I've been meaning to run that again and play
23:20	anyn	http://paste.lisp.org/display/68403
23:21	anyn	converted the celcius example to java-gnome
23:21	anyn	it's probably more verbose than it needs to be, but it works
23:21	spacebat	and picolisp has no special forms, you just bypass evaluation by declaring a function like (de myfunc X (;;in here X is a list of all arguments, and you can evaluate what you want))
23:21	rhickey	gnuvince_: It's a panel - me, Will Clinger, Kent Pitman, and Martin Simmons opining about the future of Lisp
23:22	spacebat	macros are just normal functions because everything is runtime
23:22	rhickey	Clojure represents my opinion pretty well
23:22	spacebat	I hope they video that talk
23:22	gnuvince_	I imagine
23:25	Chouser	hm, using a javascript debugger to examine clojure data structures is ... tricky.
23:52	cads	spacebat, have you read heinlein's stranger in a strange land?
23:56	spacebat	no, its just been on my list forever
23:57	spacebat	and I've spent enough time on slashdot for grok to slip into my vocab
23:57	dnm	Howdy.
23:58	Chouser	dnm: hi!