#clojure – 2010-02-27

2010-02-27

00:33	chouser	slyphon: I'd use a vector there.
00:33	chouser	slyphon: I'd use a vector there.
00:34	slyphon	yeah, i thought so
00:34	chouser	helps suggest to people that that's where 'ctx' is being introduced or defined.
00:35	slyphon	chouser: in a similar vein, i'm doing a similar pattern with a MBeansServerConnection, only with that macro i'm handing in the jmx-url and the sym to bind to
00:35	slyphon	should i make it like [sym jmx-url] so it's like a 'let'
00:35	Apage43	waha
00:36	Apage43	i saved the day at work today.. with the power of clojure
00:39	cemerick	sheesh, the funders page is long now
02:05	slyphon	you know you're getting silly when you start writing (defmacro dosomething `(defmacro ...))
02:10	Crowbar7	lol
02:11	slyphon	You're Doing it Wrong
02:11	G0SUB	slyphon, http://www.xach.com/img/doing-it-wrong-at-a4.jpg
02:11	slyphon	hahaha
02:12	G0SUB	:)
02:12	slyphon	who is that in the picture?
02:12	G0SUB	slyphon, I have that pic pasted on my office wall
02:12	slyphon	:D
02:12	G0SUB	slyphon, dude!
02:12	slyphon	:/
02:12	G0SUB	slyphon, that's Uncle John
02:12	slyphon	is that knuth?
02:13	G0SUB	slyphon, John McCarthy. the discoverer of Lisp.
02:13	slyphon	ohhhhhh
02:13	slyphon	right right right
02:13	slyphon	i don't think i've ever seen a photo of him before
02:13	slyphon	i imagined him tweedier
02:13	G0SUB	slyphon, well, he was handsome :)
02:13	slyphon	:D
02:14	slyphon	heh, i haven't seen 'xach' in forever
02:14	slyphon	since i stopped harrasing him in #lisp
02:15	G0SUB	slyphon, hehe. He is active on proggit.
02:16	slyphon	ah, right on
02:19	LauJensen	Morning team
02:28	G0SUB	LauJensen, it's afternoon here :)
02:29	LauJensen	its a big earth :)
02:29	G0SUB	LauJensen, indeed :)
05:31	hamza	gents i have a list of true false values (true false) how can i
05:31	hamza	apply or or and on them?
05:35	morphling	hamza: and and or aren't functions, you have to wrap them like this: (fn [a b] (and a b))
05:35	ska2342	hamza: can't you use every?
05:37	ska2342	,(every? true? '(true true))
05:37	clojurebot	true
05:38	ska2342	,(some true? '(false true false))
05:38	clojurebot	true
05:39	hamza	thanks a lot guys, every and some would work.
06:07	dsop	does someone know the license of the clojure logo
06:08	spariev	dsop: http://groups.google.com/group/clojure/browse_thread/thread/7f179c79f0d0bb3e - might be relevant
07:16	Licenser	sighs
07:55	bsteuber	am I the only person not satisfied with (comment foo bar) returning nil instead of being completely ignored by the preprocessor?
08:02	Chousuke	bsteuber: use #_ if you want to ignore a form
08:03	Chousuke	bsteuber: comment is just a macro so the reader can't do anything about it :)
08:05	hamza	gents, i have a seqence of sequences i would like to transfor every say second item in the inner sequences, ((:a :b) (:c :b)) to ((:a :d) (:c :d)) is there a better way to do it then maping over the outer sequence and using subvec replace the item..
08:07	bsteuber	Chousuke: I know, I'd just prefer comment to be "special" so I could use it everywhere like other comment syntax
08:07	bsteuber	or have something like #_ to ignore multiple forms
08:07	Chousuke	bsteuber: you can do #_(comment ...) :)
08:07	bsteuber	og, I can use #_(foo bar), right? stupid me :)
08:08	Chousuke	I think the comment macro is mostly intended for example code at the top level rather than any inline comments
08:09	bsteuber	hm, I see
08:09	Chousuke	the contents of the comment macro get properly syntax highlighted and can be easily evaluated using eg. slime
08:09	bsteuber	ok, so I'll use #_(...) to comment out binding forms etc.
08:10	bsteuber	thanks for clarification
08:23	bsteuber	hamza: why subvec? I guess my naive implementation would me something like
08:23	bsteuber	(map (fn [[x y]] [x (f y)]) some-seq)
08:24	bsteuber	how does your code look like?
08:28	hamza	bsteuber: that looks much better than mine, i'll go with yours. I was splitting them with nth then putting them back together..
08:29	jeffmess	has anyone here got clojure in action and joy of clojure? which would you recommend out of the two?
08:34	bsteuber	jeffmess: hard to tell with unfinished books - I'll probably read both once they're out :)
08:38	spariev	jeffmess: imo Joy Of Clojure is more polished at the time being
08:40	jeffmess	spariev: thats what i was leaning towards
08:41	jeffmess	thanks!
08:41	spariev	np
11:02	joshua-choi	Is anyone watching? I have a question—is there a more efficient way to change a map?
11:02	joshua-choi	For instance, I want to do (->> my-map (filter #(< (val %) 10)) (into {})), but that seems so inefficient to me.
11:04	Raynes	joshua-choi: I don't know about the efficiency of such a thing, but I'm pretty sure that's how it's usually done.
11:07	joshua-choi	Yeah, I was afraid so. But it seems to create a lazy sequence of map-entries, puts some of them into a completely new map transient, makes the transient persistent, and then destroys the old map.
11:07	joshua-choi	I don't know how Clojure's data structures work internally that well, but I was hoping that there would be a less wasteful way. Oh well.
11:10	bsteuber	maybe you could manually loop through the map and directly build the transient?
11:19	Chousuke	joshua-choi: that's pretty much the most efficient way to do it.
11:20	joshua-choi	bsteuder's suggestion? Or filter/into?
11:20	Chousuke	filter/into
11:21	Chousuke	the seq is just a view to the original map, so "building" it doesn't cost much at all, and into is the most efficient way to build a map out of a sequence
11:22	Raynes	I'm so into into.
11:23	joshua-choi	Chousuke: Okay, thanks. That's reassuring.
11:23	Chousuke	of course, you could be more efficient by using mutable data structures, but then you forfeit all the benefits of functional programming
11:23	joshua-choi	Well, I guess you could do what bsteuder suggested. Make a function that internally mutated a transient.
11:24	Chousuke	I don't think that would be much more efficient than the into approach
12:14	krumholt	hi i want to compile a file. I can require it but when i try to compile it i get an exceptionj ava.io.IOException: No such file or directory (heightmap.clj:1) what could be the problem?
12:34	dabd	I have the following on my classpath "/home/foo/" and a clojure file in "/home/foo/bar/baz.clj" but if I try to use clojure.lang.RT.loadResourceScript("bar/baz.clj") from a Java class it doesn't find the file. What am I missing?
13:23	dsop	are there plans to get clojure dev on gmane?
13:41	rhickey_	dsop: not if that opens a gateway to posts from gmane
14:40	Raynes	It's quiet...
14:40	Raynes	Too quiet.
14:41	ordnungswidrig	shhhhhh
14:52	arohner	I've been feeling the need to write a library to validate complex datastructures. Things like this datastructure is a nested map. it has keys foo, bar. Bar's value is a vector of length 5
14:52	arohner	Does anyone know of a library like this? Is there anything worth copying from other languages?
14:56	AWizzArd	arohner: this sounds useful and nice, and I would love to have such a tool. Just a comment though: when you create your complex datastructures through a constructor function (make-my-thing ...) then this fn should output only valid complex datastructures.
14:58	arohner	AWizzArd: my general idea is a macro that will produce a fn. (valid? validator-fn object) returns a bool. (validate! validator-fn obj) throws an exception on failure. Then you can hook that into pre/post conditions
14:58	arohner	{:pre [(valid? foo arg1) (valid? bar arg2)]}
14:59	arohner	I'm starting to want a pre/post conditions that run in production. i.e. a "debug" pre/post and "always" pre/post
15:02	webben	arohner: Not something I've used, but http://rjbs.manxome.org/rx/ might be worth a look. (Very similar problem space.)
15:03	arohner	webben: thanks! exactly the kind of example I'm looking for
15:04	webben	yw
15:06	hiredman	arohner: there was a jcromartie in here working on some kind of validation system for structs
15:06	hiredman	http://gist.github.com/314809
15:07	arohner	hiredman: yeah, I saw some of his examples. It seemed geared towards web input validation. I need something more general purpose, for backend code
15:07	arohner	and I need working code, rather than example usage :-)
15:07	hiredman	right
15:11	ordnungswidrig	arohner: I just pushed clj-validate to github the other day.
15:11	rsh	what is the difference between a ref and an atom? I can't figure it out from the clojure.org doc
15:11	ordnungswidrig	arohner: not complete but working for me
15:12	StartsWithK	rsh you can place a ref in a transaction
15:14	rsh	thanks StartsWithK
15:19	mabes	arohner: if you end up writing a rx (or similar) validator it would be awesome it you shared your work (via the ML or back to the Rx project).. I'm just looking at it now and it seems very useful
16:07	eglyph	hello everybody. i'm trying to setup emacs together with clojure and compojure. slime plays fine with clojure, but i can't get compojure working.
16:10	eglyph	if i (require) it, it fails with No Message, if i (use) it it fails with java.lang.NoClassDefFoundError, so I guess, it's classpath related thing
16:10	eglyph	but then, (System/getProperty "java.class.path") shows that compojure and all the dependencies are in classpath
16:11	eglyph	what elese should i check?
16:17	StartsWithK	Can you place something else on cp and check that it also fails?
16:19	eglyph	I just tried compojure without emacs. it fails too, so it's definitely classpath related
16:21	StartsWithK	Are you using the same version of clojure in all your tools? Is something maybe using -bootclasspath option?
16:21	eglyph	yes, the version is the same. it's just symlinked everywhere
16:22	StartsWithK	Can you paste java cmd call you use
16:22	eglyph	one moment
16:24	eglyph	http://paste.org/pastebin/view/15839
16:24	eglyph	my ~/.clojure contains clojure.jar and clojure-contrib.jar
16:25	StartsWithK	Heh, can you paste it here :) i'm on a (cheep) phone
16:26	eglyph	java -cp $HOME/.clojure/:/opt/compojure:/opt/compojure/deps/: clojure.main
16:26	eglyph
16:28	eglyph	putting jline somewhere in classpath works. it makes me wonder
16:28	StartsWithK	Weird
16:28	eglyph	agreed
16:29	StartsWithK	I think thats a new one :)
16:29	eglyph	basically all the tutorials on compojure boil down to "put everything into your classpath"
16:30	eglyph	so i even tried to copy them all into classpath instead of symlinking
16:32	StartsWithK	And with jline it all works in emacs too?
16:33	eglyph	let me check it. i was playing with it from a shell
16:39	eglyph	emacs gives the same error as for compojure. so I'm doing something completely wrong
16:41	StartsWithK	Anything i compojure aot compiled with different clojure version?
16:44	eglyph	i think no, because i've built it from git repo. so it should use my version of clojure
16:44	eglyph	but i'm not sure
16:47	somnium	eglyph: maybe try getting it from clojars via lein. its easy and likely to resolve any classpath/versioning issues
16:50	eglyph	never heard of clojars. :) how do i use it? they explain how to "push", but i need "pull", do i?
16:53	qed	eglyph: clojars.org
16:54	StartsWithK	clojars.org/repo
16:55	StartsWithK	Find a jar manualy if you dont want to use any extra tools
16:57	eglyph	works. thank you.
16:58	StartsWithK_home	java -cp "/home/you/.clojure/:/opt/compojure:/opt/compojure/deps/" clojure.main
16:58	StartsWithK_home	will this work?
16:58	eglyph	the .jar from repo is twice as big the one i've built
16:59	eglyph	exactly this string doesn't work. it was my initial attempt.
18:36	technomancy	_ato: having some trouble scping to clojars@clojars.org; any idea what's up?
20:42	maxhodak	http://github.com/myfit/clj-facebook/blob/master/src/facebook/client.clj#L58
20:42	maxhodak	dying saying "First argument to def must be a Symbol"
20:43	maxhodak	but (prn (type method)) gives "clojure.lang.Symbol"
20:50	the-kenny	maxhodak: generate-methods must be a macro too, you can't supply a variable containing a symbol as the first argument
20:54	the-kenny	Oh, and I'd also not use (def ...) inside a function. That's not good
20:54	maxhodak	the-kenny: so i got it to work when i replaced the (first method) (second method) ... with a let
20:55	maxhodak	i guess the macro acts directly on the arguments, not the arguments' evaluations
20:56	the-kenny	exactly
20:56	maxhodak	the-kenny: http://github.com/myfit/clj-facebook/blob/master/src/facebook/client.clj#L58
20:57	maxhodak	so now if i replace ~args with [] it works
20:57	maxhodak	(~methods works fine)
20:57	maxhodak	but the ~args part is dying
20:58	Chousuke	maxhodak: you have ~@args
20:58	maxhodak	Chousuke: yeah thats me playing with combinations to see what it does
20:58	the-kenny	(do ~@`(1 2 3)) expands to (do 1 2 3). You want ~ without the @
20:58	maxhodak	Chousuke: (since ~args wasn't working, i tried ~@args)
20:59	Chousuke	~args should work
20:59	clojurebot	what should I do today, it is the weekend and all
20:59	Chousuke	providing it's a vector, of course
20:59	maxhodak	Chousuke: Don't know how to create ISeq from: clojure.lang.Symbol
20:59	maxhodak	Chousuke: it is, it's the 3rd part of each vector in fb-methods
21:00	maxhodak	(prn (type args)) on L78 says thats right
21:01	maxhodak	clojure.lang.PersistentVector
21:01	Chousuke	maybe you have the error somewhere else
21:01	Chousuke	because as far as I can tell, that's fine :/
21:02	Chousuke	... ah
21:02	Chousuke	never mind
21:02	Chousuke	you're never actually passing a vector to the macro
21:03	Chousuke	you're passing the symbol args
21:03	Chousuke	you can't use macros in a doseq like that .P
21:03	maxhodak	oh?
21:03	maxhodak	hmm
21:03	Chousuke	arguments to macros are not evaluated, so when you call (define-method symb map args) you're calling it with three symbols as an argument
21:03	Chousuke	as arguments, even :P
21:04	maxhodak	i guess i could just put the defn in the doseq
21:04	Chousuke	that won't work very well either.
21:04	maxhodak	well, no that wouldn't work
21:04	maxhodak	i just don't want to list out all of the methods as separate fxns
21:05	maxhodak	it's duplicating basically all of the code for each
21:05	Chousuke	well you can always access the method table directly in the macro
21:05	maxhodak	i could do (define-method 'admin-get-allocation "admin.getAllocation" []) ...
21:05	maxhodak	rather than looping through it
21:06	Chousuke	that would be (define-method admin-get-allocation "..." [])
21:06	maxhodak	that'd be simple enough with a column-oriented selection
21:06	maxhodak	though a little wasteful
21:06	maxhodak	yeah
21:06	Chousuke	but hm, the non-toplevel def in your make-facebook-connection is also suspect :P
21:07	Chousuke	it's not actually making a connection :P
21:07	maxhodak	Chousuke: it is; i should use Java sockets or a with-facebook type construct
21:07	maxhodak	Chousuke: no but fb-conn is references in call-method
21:07	maxhodak	s/references/referenced
21:07	Chousuke	at least call it init-facebook-info! or something that indicates it's destructive.
21:07	maxhodak	so you don't need to pass a "conn" variable anywhere
21:07	maxhodak	destructive?
21:07	Chousuke	yes
21:08	Chousuke	it redefines a global variable, so it's destructive
21:08	Chousuke	or has side-effects, whichever terminology you prefer :P
21:08	maxhodak	ok
21:09	maxhodak	renaming it init-facebook!
21:09	maxhodak	does the bang operator usually denote side-effects?
21:10	Chousuke	an approach like that is fine if you will only ever have one connection, but if you ever have the need for more, that'll become your primary pain :)
21:10	Chousuke	yeah.
21:10	maxhodak	Chousuke: yeah i've never seen an fb app that's dealt with more than one api key
21:10	maxhodak	Chousuke: but, it is possible, and should be refactored to use some kind of open-stack eventualy
21:13	Chousuke	since you're doing ugly things anyway, you could perhaps just use eval in generate-methods :P
21:13	Chousuke	I think (eval `(define-method ~symb ~map ~args)) in the doseq would work just fine :P
21:15	Chousuke	somnium: the dark side is tempting
21:16	technomancy	that can be done with a macro instead of eval; see clojure.http.resourcefully
21:17	Chousuke	sure. I was just suggesting a quick'n'dirty fix :P
21:17	technomancy	http://p.hagelb.org/define-method.html
21:18	maxhodak	technomancy: yeah i was basing my implementation off of resourcefully's example
21:19	maxhodak	technomancy: the issue was that you have to call (define-method) directly for each arg set, rather than putting it in a doseq or map
21:19	maxhodak	(right?)
21:19	technomancy	maxhodak: you need that to get line numbers in stack traces
21:20	technomancy	otherwise you can use a doseq
21:34	maxhodak	to build a hashmap of {:foo foo :bar bar ... } can you do something like (doseq [arg args] `{:~arg ~arg}) ?
21:44	fanatico	maxhodak: http://gist.github.com/304345
21:45	somnium	Chousuke: is your reader on github?
21:46	somnium	Chousuke: ah, found it
21:47	fanatico	maxhodak: damn, actually that's an older version that doesn't work with locals. I'll try to dig up the current version.
21:48	maxhodak	fanatico: awesome.. that looks like what i'm trying to do though
21:53	fanatico	maxhodak: (defmacro named-map [& keys] `(zipmap (map keyword '~keys) (list ~@keys)))
21:53	fanatico	(let [a 1, b 2] (named-map a b)) ; => {:a 1, :b 2}
21:56	maxhodak	so that's not quite what i'm trying to do... i want to pass in a vector like [integration_point_name]
21:56	maxhodak	and build a hashmap of {:integration_point_name integration_point_name ...}
21:56	maxhodak	like let me push to github so i can show you exactly what i mean
21:59	maxhodak	http://github.com/myfit/clj-facebook/blob/master/src/facebook/client.clj#L65
22:00	maxhodak	i'm building a map of arguments to pass ingo call-method there; they have to be named and they don't necessarily have a default value
22:06	fanatico	something like (let [a 1 b 2] (named-map [a b])) => {:a 1 :b 2} ?
22:07	fanatico	just through a let around the body of the macro and deconstruct keys.
22:08	fanatico	s/through/throw
22:19	maxhodak	fanatico: well, its a macro for generating functions (defn's)
22:19	maxhodak	so rather than {:a 1 :b 2}, i want {:a a :b b} to be filled in by my defn's arguments [a b]
22:20	fanatico	just merge the named map with the defaults.
22:26	fanatico	maxhodak: something like http://gist.github.com/317153
23:47	DeusExPikachu	what are some common pitfalls/gotchas for using eval?