#clojure – 2008-07-21

2008-07-21

07:42	abrooks	Colin, of Project Euler just emailed me to say that he added Clojure to the list of available languages. If you've been solving your PE problems with Clojure you can now show that to the public. :)
11:01	Chouser	abrooks: that probably warrants a post to the list
11:32	Chouser	drewr: daily atom?
11:33	Chouser	hourly rss?
11:33	Chouser	I guess every IRC post could be its own feed entry...
11:44	drewr	I couldn't come up with a good solution.
11:44	drewr	Every post shouldn't be an entry. That could get out of control.
11:45	drewr	Maybe hourly would work.
11:45	drewr	No entry if there wasn't activity.
11:46	Chouser	hourly would fit in with the current design pretty well.
15:06	rhickey_	note, latest svn has new namespaces for set et al -> clojure.set etc. aliases coming...
15:40	Chouser	can static functions not be called using (classname/methodname arg) syntax?
15:41	Chouser	static methods I mean.
15:42	cemerick	Chouser: should work -- I've been using that for a while
15:43	cemerick	er, no, just for fields
15:43	cemerick	sorry -- there's a contrib lib for that -- import-static, I think
15:43	rhickey_	user=> (Boolean/valueOf "true")
15:43	rhickey_	true
15:44	Chouser	yep, sorry -- it's non-static method. I'm trying to run some old code and wasn't paying close enough attention.
16:20	mebaran151	is there a linter for clojure that I can call from emacs?
16:21	Chouser	mebaran151: to check for syntax error or something?
16:21	mebaran151	just to prettify the code
16:21	mebaran151	and fix nasty indentation
16:21	mebaran151	I still haven't gotten down a good LISP indentation style yet
16:22	Chouser	ah. I think there's a clojure-mode, but I have no idea if it helps with indentation or not. I don't use emacs.
16:23	toyvo	mebaran151: tell me if you find one :) I have been sitting in scheme-mode, which indents OK except some parts that are idiomatic to Clojure
16:23	rhickey_	http://clojure.codestuffs.com/
16:23	mebaran151	Chouser, what editor do you use?
16:24	mebaran151	I have the clojure mode, but I don't think it contains a linter
16:24	Chouser	vim
16:24	toyvo	rhcickey_: thanks Rich, looks good.
16:25	Chouser	the plugin I use for indentation is imperfect -- perhaps similar to what toyvo described.
20:25	toyvo	I also have Clojure in inferior-lisp, for what it's worth for now. But must check out that Clojure mode.. Anyone tried running a long-standing Clojure with detachtty? Any issues with that? That would be fun - a dynamic JVM in production.
20:25	rhickey_	mebaran151: still not quite sure what you mean by linter, but if you select a region and do C-M-\ clojure mode will re-indent the region
20:26	mebaran151	you sure it's C-m-\? That just seems to add a new line to the top of my buffer.
20:27	rhickey_	mebaran151: did you have a region selected?
20:28	mebaran151	yeah
20:28	mebaran151	that's ctrl-m backslash right?
20:29	rhickey_	mebaran151: ctrl-meta-\
20:29	rhickey_	all together
20:30	mebaran151	that doesn't seem to change anything
20:30	rhickey_	may be ctrl-alt-\ depending on os
20:30	mebaran151	just put it on a nasty bit of clojure I'm working on it and it slightly forgot to do anything
20:31	rhickey_	if you go down the code and type Tab on each line does it indent?
20:34	toyvo	mebaran151: maybe you are in text mode and not in scheme/lisp/clojure mode? I go to scheme mode by pressing escape, then x, then typing scheme-mode (enter). Should be similar for other modes.
20:34	mebaran151	it's seems to be syntax highlighting properly
20:36	mebaran151	how do I reindent in scheme mode
20:36	mebaran151	just switched to it
20:37	toyvo	M-x mark-whole-buffer and then M-x escape-region. M-x - emacs jargon for Esc then x, or Alt+x, or Meta+x
20:38	toyvo	sorry, indent-region, not escape-region
20:38	toyvo	these commands should be the same in any mode
20:43	rhickey_	namespace aliases are up, via Graham Fawcett (alias 'set 'clojure.set)
20:44	Chouser	nice
20:46	Chouser	now give scgilardi a few minutes to integrate that into lib...
20:46	toyvo	Do you guys plan to go for Clojure code repo like CPAN or Scala Bazaars? Are those 12 or so files in SVN I've seen (under User Contributions) the repository as of today? Or is the preferred way of distributing Clojure code is in jars?
20:50	Chouser	toyvo: I'm sure someone else can answer better than I, but my understanding is that the relationship between directory structure namespaces is currently in flux.
20:50	Chouser	once that has settled down and lib (or something like it?) has been rolled into stock clojure releases, we'll have sufficient framework to think about the next stage.
20:51	Chouser	for now there's clojure-contrib and various bits of .cljs and .jars here and there on the web.
20:53	Chouser	The fact that Java has nothing like CPAN (that I know of?) and "hasn't needed it" may mean Clojure never gets something like it either. Dunno.
20:53	mebaran151	what do other lisps do for pkg management?
20:53	toyvo	Chouser: Thanks - that's how the situation looks to me. Hmm...
20:54	toyvo	I know PLT Scheme has a pretty innovative PlaneT repository. It allows you to do something equivalent to Java's code loading over HTTP.
20:54	toyvo	THat is, you just write (require (planet ...)) and the system downloads and installs the correct version of the package and its dependencies for you.
20:54	leadnose	common lisp has asdf and cl-build
20:54	Chouser	mebaran151: gentoo seems to actively package and distribute common lisp libs via their standard OS distro system.
20:54	mebaran151	without something like CPAN, the biggest problem is that most libraries won't reuse the utils in the others
20:55	mebaran151	because dependency management would be too much of a pain
20:56	mebaran151	btw, I'm maintaining a clojure pkg for archlinux
20:57	toyvo	mebaran151: great!
20:57	mebaran151	I wish you guys would just include the jline jar inside clojure
20:58	Chouser	I don't use JLine.
20:58	Chouser	I like rlwrap. :-)
20:58	mebaran151	I was thinking of making everyone just use rlwrap, but I wondered if there were any downsides
20:58	toyvo	Ah that's what it is! I'm on rlwrap too :)
20:59	toyvo	I've not written much java before this week - but supposedly something like JLine is NOT included, can you load it over HTTP? Is that something URLClassLoader is about?
21:00	mebaran151	I don't like the idea of loading remote code: seems like a huge security risk
21:00	Chouser	toyvo: I think so, but I don't think it caches it anywhere.
21:01	toyvo	Then we could mash-up a clojure library that loads it and caches in /tmp.. Yes, it's a huge security risk. But on the other hand, loading Linux packages - isn't that a risk? I wonder.
21:01	Chouser	since clojure source can have Java dependencies, it seems like a CPAN-for-clojure would actually have to be a pretty complete Java/jar/clj fetching, dependency resolving, caching thing.
21:02	mebaran151	toyvo, it's a very explicit risk though
21:02	mebaran151	when I install package, I have to explicit run it before evil stuff happens
21:02	mebaran151	in a remote URL loading scheme, someone could just mangle the byte code to point to their evil botnet maker
21:03	toyvo	Ah yes... Perhaps certificates can help?
21:03	toyvo	Chouser: I've heard Maven does something like that? Or no? Sorry, my Java is rudimentary.
21:04	mebaran151	yes, maven does automatically pull dependency
21:04	mebaran151	there actually really isn't any reason its infrastructure couldn't be exploited: scala does something
21:04	mebaran151	the only problem is that maven is very much wedded to a compile cycle, which may or may not be appropriate for a lsip
21:05	toyvo	Looks like... So that may be a good start... If it has classes we can take out and reuse.
21:05	Chouser	if we think of "compiling" clojure as being more of "fetch and compile java dependencies, fetch .clj and run any gen-class stuff" it maps ok, right?
21:06	mebaran151	maybe, though compiling is a very external process in Java Scala land
21:06	toyvo	There's another related question I spent some time thinking about: can you load new versions of classes into a JVM without restarting it? Erlang VM guarantees such hot uploads, for JVM I was a bit confused..
21:07	mebaran151	JVM has a security model that interferes with this, but it's currently a JSR
21:07	mebaran151	you could try something like java rebel, but it's proprietary and I don't see how it maintains bytecode security
21:08	Chouser	Clojure works hard to allow dynamic code changes without actually having to replace Java classes.
21:08	mebaran151	you can also try class loader hacks, but those are always very memory leaky
21:09	toyvo	Ah... Right! Hm.. But in Clojure, if I load new proxies, these are different classes, right? So the old ones can get recycled.
21:11	toyvo	But then, it looks like distributing Clojure as compiled bytecodes is out, because new versions cannot be hot-updated in the JVM as easily, having static class names.
21:11	mebaran151	for a servlet, is there any real downside to using a proxy: I know their slower to instantiate, but aren't servlets only loaded once at server boot?
21:11	mebaran151	toyvo, I think the ASM library might support some name mangling
21:12	cemerick	toyvo: I understand that Rich is contemplating a FASL-esque distributable path, rather than compiling to bytecode
21:13	rhickey_	right now the story is, dynamic code means load new source
21:13	toyvo	I'm googling for "FASL"... :)
21:14	cemerick	toyvo: you won't find much -- there's no spec or anything -- it appears to be implemented differently in every lisp
21:14	toyvo	oh, but what IS it? I'm los
21:15	toyvo	Ah, got it
21:16	mebaran151	can Java call clojure?
21:17	toyvo	mebaran151: that was a good question. I'm interested too if proxy servlets are in any way inferior. They seem superior in being easily reloaded - modified from a REPL.
21:17	mebaran151	well I've read that proxy's instantiate much slower
21:17	mebaran151	but for a server, I think that a servlet only needs to be loaded once
21:18	rhickey_	The best recipe for servlets is to use gen-and-save-class, this gives you a static class stub, with all of the real logic in Clojure, and thus re-loadable
21:18	mebaran151	but right now, I'd prefer not create trash class files as develop the servlet
21:18	rhickey_	?
21:19	mebaran151	well doesn't it write a class file
21:19	mebaran151	or is this class file static as I change it's internal logic
21:19	rhickey_	yes, and the same one will be useful for the entire lifecycle of development
21:19	rhickey_	it doesn't need to be regenerated
21:21	rhickey_	note: new in svn - all of the .cljs have moved out of the root! and now follow classpath rules
21:22	toyvo	gen-and-save-class - is it only in SVN? My system seems not to find it.
21:22	toyvo	Let me upgrade
21:22	mebaran151	rhickey, what do you mean by moved out of root?
21:24	rhickey_	boot.clj et al were all in the root of the jar, now in classpath-compliant subdirectories corresponding to the packages of the classes of the generated functions
21:24	rhickey_	user=> map
21:24	rhickey_	clojure.map__571
21:24	rhickey_	user=> clojure.set/union
21:24	rhickey_	clojure.set.union__1962
21:26	rhickey_	in /clojure/boot.clj and /clojure/set/set.clj respectively
21:30	toyvo	Has anyone thought of writing a Clojure bot to sit in the IRC? Like Haskell's Lambda bot?
21:31	Chouser	it's been mentioned several times. Nobody's quite bothered to do it yet though.
21:32	toyvo	I'll give it an hour.. Seems to be a fun thing to do.
21:32	mebaran151	ah, so this is more of an internal thing, the classpath edits?
21:34	rhickey_	well, some of the libraries need to be manually loaded, so people might need to edit the paths. Otherwise, it is for tooling, lots of Java support for finding things in classpaths, so now Clojure is more compliant. It also provides a known schema for file layout that can be leveraged by the lib/require framework.
21:35	drewr	,test
21:35	clojurebot	I don't yet know what "test" means.
21:35	drewr	clojurebot: Learn then!
21:35	Chouser	,(println "hello everyone")
21:35	clojurebot	I don't yet know what "(println "hello everyone")" means.
21:35	Chouser	awww
21:35	drewr	:-)
21:36	drewr	Haven't decided yet what to hook into it. Probably the DOC function for starters.
21:36	toyvo	Ah
21:36	toyvo	Neat
21:36	Chouser	Doing any Java sandbox stuff? Any logging?
21:37	drewr	Nope, basically an echo service currently.
21:38	toyvo	,(doc gen-and-save-class)
21:38	clojurebot	I don't yet know what "(doc gen-and-save-class)" means.
21:38	drewr	I didn't do logging because I didn't have a dedicated box for it. I'm going to switch my VPS to a vendor whose network allows IRC and then I'll fire it up.
21:39	toyvo	,(doc int)
21:39	Chouser	drewr: ok. When that's done, if you're interested we can look at rolling clojure-log into it.
21:39	clojurebot	I don't yet know what "(doc int)" means.
21:40	toyvo	,(def id #(%))
21:40	clojurebot	I don't yet know what "(def id #(%))" means.
21:40	rhickey_	drewr: doc is easy, just echo (doc x) => http://clojure.org/api#x
21:40	Chouser	drewr: right now clojure-log is connected from my aging linux workstation over residential DSL. Anything would be more robust, I'm sure.
21:41	drewr	Chouser: Yup. I didn't want to bother unless it was going to improve on what you've done.
21:42	toyvo	drewr: so clojurebot is just an echo? man, i'm confused :) I kept thinking it's an interpreter with an unknown limited set of commands.
21:43	toyvo	Or is there something it does right now?
21:43	toyvo	,(+ 1 2 3)
21:43	clojurebot	I don't yet know what "(+ 1 2 3)" means.
21:43	drewr	toyvo: It's unlikely I'll allow readable expressions.
21:43	drewr	I would think it's too hard to do it securely, so I haven't given it much thought.
21:43	toyvo	drewr: what does/will it allow then?
21:44	drewr	toyvo: Print docstrings and google results perhaps.
21:45	toyvo	drewr: Well... Are you sure security is such a big big issue?
21:45	rhickey_	drewr: http://calumleslie.blogspot.com/2008/06/simple-jvm-sandboxing.html
21:45	toyvo	Rich: thanks for the link!
22:18	fyuryu	is it normal, that stuff gets printed twice? http://paste.lisp.org/display/64026
22:28	Chouser	what's swing-frame?
22:28	fyuryu	in other words: do methods contained in proxy are somehow executed twice?
22:29	fyuryu	Chouser: oh, just a function that creates a swing-frame and packs the applet into into it
22:31	Chouser	the body of your "setup" method shouldn't be called at all when it's defined
22:32	Chouser	you're sure swing-frame isn't somehow causing your setup method to be called twice?
22:34	fyuryu	Chouser: no, applets require (according to javadoc) that a "init" call when inserted into a swing frame, but I don't call "setup" myself
22:36	fyuryu	Chouser: maybe it's a Processing thing
22:41	fyuryu	Chouser: ok, I got it. I created the frame in a try catch block