#clojure – 2008-09-04

2008-09-04

00:00	Myoma	by the way I don't intend to hack it so maybe this is slightly off topic ..
00:01	arohner	one thing that helped me was to read the stack trace
00:02	arohner	do something that will cause a stack trace, and then read the stack trace
00:02	arohner	i.e. (foo 1)
00:02	arohner	and then start at something that looks interesting, like Repl.main or eval()
00:03	arohner	and then go over to Repl.java and follow the code
10:40	Chouser	ah! I just now got the point about a partial refer of 'clojure and then a later full default refer.
10:52	rhickey	Chouser: ok, so now what about defns?
10:53	Chouser	makes sense to me
10:53	rhickey	I can work with your patch as-is, but I think I'm locked out of checkins on SF today
10:54	Chouser	gah
10:54	Chouser	I didn't hear a whole lot of objection to moving the repo to google code.
10:54	rhickey	this kind of thing has been pretty rare on SF, I wonder how Google Code compares?
10:55	Chouser	that is one of the benefits of a distributed vcs (git or hg instead of svn) -- the "central" server isn't all that important anymore.
10:55	rhickey	http://code.google.com/p/clojure/ is in the wings
10:56	rhickey	Chouser: I'm not sure that's true - where do I put my stuff so you can get it?
10:56	Chouser	Since I'm using git-svn, I have a complete history of the clojure repo locally. I could look into importing that to google if you want.
10:56	rhickey	where's the canonic version, etc
10:57	Chouser	sure, there's still value in a generally available canonical server. But routing around damage is much easier.
10:57	rhickey	Chouser: I'll have to move to EPL before I put it up
10:57	Chouser	oh, that's right. ok.
10:58	rhickey	Chouser: I think DVCS is neat, but maybe not a good fit for the benevolent dictator model :)
11:02	Chouser	heh, well, I don't think that matters much. We're all using dvcs anyway, even if you aren't.
11:02	rhickey	right
11:02	Chouser	ok maybe not "all".
11:04	Chouser	but with dvcs if you're in a situation like this where the central server's down, you can continue to do checkins, and all your data and meta-data can be synced up later -- either with the same central server or a new one (in the case of the old one going away forever).
11:04	Chouser	of course the tool integration is not as deep yet.
11:05	Chouser	You'll be using dvcs eventually, so I don't really feel I need to convince you right now. :-)
11:06	rhickey	Chouser: I understand, but not having that forces a 'working head' mentality that multiple local working copies doesn't, plus far less merging (i.e. none for me)
11:07	rhickey	I've used Mercurial for personal things, much more of a hassle than SVN built into IntelliJ
11:07	cemerick	I guess I'll have to get over my google code aversion issues ;-)
11:08	rhickey	I routinely work on Clojure on 3 different machines in different locations, and when I move I need to check in - the result is lots of working checkins
11:09	rhickey	cemerick: what are your issues with google code?
11:10	cemerick	rhickey: nothing substantive, really. I think we had this discussion before, though. I don't trust google on a variety of levels, but that's my problem more than anything else.
11:11	rhickey	I'd love to hear from someone re: uptime etc
11:11	cemerick	I don't actually think google code provides much more than svn + trac (if you were to host such things on your own, although I'm sure there are trac hosts floating about). Given their resources, I was pretty disappointed in it.
11:12	Chouser	I'm happy to know that there are various dvcs copies of the clojure repo around -- my own, github, hg mirrors, etc. If google (or sf.net for that matter) loses all the data, we'll be able to reconstitute it with very little fuss.
11:13	rhickey	Right now Clojure doesn't even have trac, and I'm not interested in hosting anything. So the issue tracking is something I'm looking for from google code
11:13	Chouser	really? You're giving in on issue tracking?
11:13	rhickey	Chouser: I fully acknowledge the superiority of DVCS in the large
11:13	rhickey	Chouser: I didn't say anyone else could enter issues
11:13	Chouser	hehe
11:14	rhickey	Well, I'm still trying for 'no known bugs'
11:15	cemerick	rhickey: personally, I'd much prefer something like assembla, but this is your baby :-)
11:15	rhickey	But I keep a todo list that's not web based and is private - keeping it online will let people know where things are going
11:20	albino	rhickey: the reason you don't want an issue tracker is for the perception of no known bugs?
11:21	rhickey	albino: no, I fix bugs as they are reported, rather than put them on a list
11:22	rhickey	cemerick: assembla looks neat, have you used them?
11:23	cemerick	rhickey: only in passing -- we host all of our stuff in-house (our svn and project mgmt stuff reside on the only server we don't lease or have colo'd somewhere). Friends of mine have used it heavily, and have very good things to say.
11:24	cemerick	I presume you'd be able to get them to set you up with a full-featured account, given that it's an open source project.
11:29	ozzilee	Does anyone know if it would be possible for multiple versions of a java library to be loaded at the same time, cordoned off in different namespaces perhaps?
11:30	rhickey	cemerick: I didn't see that offered, but did see this: http://blog.assembla.com/assemblablog/tabid/12618/bid/5430/An-explosion-ate-our-servers-how-cool-is-that.aspx
11:30	cemerick	ozzilee: you would need to use different classloaders -- same as in regular java
11:31	ozzilee	cemerick: Hmm. Ok thanks.
11:32	cemerick	rhickey: hrm, unapologetically in startup mode, I suppose
11:32	rhickey	cemerick: right
12:17	jgracin	default target jvm version on Java 6 is 1.4, right?
12:17	jgracin	in javac, I mean
12:19	jgracin	nope.
15:17	jgracin	rhickey: the documentation on reader forms claims that symbols beginning or ending with : are reserved by Clojure. Surely, you didn't mean keyword literals, did you? Am I understanding something incorrectly?
15:18	rhickey	if it begins with : it's not a symbol. "reserved by Clojure" means its interpretation is reserved, i.e. it can't be used generally as a symbol
15:19	jgracin	oh, ok.
15:20	jgracin	what is the equivalent of keywordp in CL? how do I check whether something is a keyword?
15:21	rhickey	keyword?
15:21	Chouser	(keyword? :foo) ==> true
15:21	jgracin	aieee! :-) how stupid can I get...
15:21	jgracin	thanks
15:22	rhickey	find-doc is your friend: (find-doc "keyword")
15:22	jgracin	cool! I didn't know about that one.
15:29	wlr	will it always be the case that recompiling anything (not just macro(s)) in a :use'd ns requires recompiling a :use'ing ns for the :use'ing ns to see the new effects?
15:31	rhickey	wlr: depends on what you are trying to 'see', new definitions of existing fns are seen without any recompiling
15:31	rhickey	getting refers to new names requires re-using (probably by just re-evaluating the defns form)
15:33	wlr	rhickey: that's what i thought but i swear i had to do a recompile after having changed a function in a a:use'd ns.
15:34	rhickey	wlr: shouldn't be
16:22	wlr	rhickey: just for the record, i mistakenly compared old output with (duh!) old output leading to the faulty conclusion that the change in the :use'd ns wasn't visible.
16:22	wlr	embarassing!
16:22	rhickey	wlr: np, glad it works
18:17	rapido	ping
20:04	joubert	Hi,
20:04	rhickey	hi
20:06	joubert	I'm trying to determine whether the parameter to a function is a map.
20:07	joubert	There is (vector?) but I am unable to find an equivalent for maps
20:07	joubert	(according to the API docs anyway)
20:07	joubert	not sure whether it is in the code base?
20:08	joubert	I guess I should look, thinking about it now
20:08	joubert	hmmm, nevermind
20:08	rhickey	(map? m)
20:09	joubert	thanks, Rich. what about a predicate for lists?
20:11	rhickey	(instance? clojure.lang.IPersistentList x)
20:11	joubert	ok, great.
20:19	joubert	btw, I see that (map?) is on the main api doc page, but not on the page for data structures where the other map forms are documented.
20:20	rhickey	not every function will appear in the descriptive docs
20:21	joubert	oh ok; but will in api main?
20:21	rhickey	there's also find-doc at the repl to help you find things that are only in the SVN and not in the API reference
20:21	rhickey	API docs document the release
22:10	arohner	local variables are not vars, right?
22:21	DrewR	You mean those defined by let?
22:21	arohner	yes
22:21	DrewR	I think they're Vars.
22:21	DrewR	They're immutable.
22:22	DrewR	I'm not sure how to tell though.
22:22	DrewR	user> (let [x 3] (class x))
22:22	DrewR	java.lang.Integer
22:23	arohner	well, (let [foo 5] (var foo)) doesn't complain
22:30	arbscht	I don't think they're Vars
22:30	arbscht	local bindings are not variable, and Vars are mutable
22:33	arbscht	arohner: that form should complain. maybe you have defined foo globally previously?
22:34	arohner	arbscht: ah, you're right
22:34	arohner	I had previously defined it
22:34	arohner	after unmapping, Caused by: java.lang.Exception: Unable to resolve var: foo in this context
22:34	DrewR	Vars are mutable?
22:35	DrewR	How so?
22:35	arohner	using set!
22:36	arbscht	Vars exist for the purpose of thread-local mutability :)
22:37	DrewR	Ah, you're right. I just never use them that way.
23:11	mbeau	just wondering where I should look in the source code to understand how the '.' operator works?
23:19	arohner	mbeau: this is kind of throwing you off the deep end, but clojure/src/jvm/clojure/lang/Compiler.java
23:19	arohner	search for DOT
23:19	arohner	a lot of Compiler.java has to do with parsing the source, and it's kind of hard to escape that
23:21	mbeau	arohner: thanks, that's where I was looking around, but as you warn it is pretty tough to see what is going on
23:23	mbeau	ok, actually I see that HostExpr is a good place to start
23:28	mbeau	really, the thing I'm curious about is how the (.foo ...) syntax is implemented
23:35	mbeau	yikes
23:38	arohner	mbeau: ?