#clojure – 2008-07-30

2008-07-30

00:00	pjb3	shoover1: that does it, thanks!
00:03	shoover1	pjb3: No problem. But by the way, I'm not sure why you don't have Compiler.loadFile, because I have it in my svn checkout and I think it's been around a while.
00:05	shoover1	It also worked with the foo.invoke code, as long as you call something in RT before Compiler.loadFile to get the runtime initialized.
00:09	pjb3	have a Compiler.loadFile, I was having IDE issues :)
00:10	pjb3	but RT.loadResourceScript works too
00:49	shoover1	For future reference I added the above code to the wiki (tweaked to show foo accepting parameters from the Java code): http://en.wikibooks.org/wiki/Clojure_Programming#Clojure_for_Java__Programmers
05:51	mac__	Hello all, is there a static method version of doto available? Or is there some clever way to get the same effect as doto on static methods? I got some java classes with a bunch of static methods that need to be called in succession and it's getting tiresome to write out the class names all the time. Or should I try to make my own macro, like sdoto or something?
06:15	hoeck	mac__: i haven't found one
06:16	mac__	Alright, guess I'll make my own macro then. Just thought I'd ask if anyone knew of anything first. Stupid to re-invent stuff ;)
06:18	hoeck	in your case, you would just need to remove the let in the doto macro to make it an sdoto
06:18	hoeck	are you doing opengl stuff?
06:19	hoeck	(thats the only api i know where one has to make several static method calls in row)
06:33	mac__	yep
06:34	mac__	using lwjgl
08:17	Chouser	shoover: oh, good. That'll be helpful.
09:02	cemerick	rhickey: is there any reason why you don't specify a charset when opening a reader in Compiler.loadFile? UTF-8 would seem to be the most reasonable default.
09:05	rhickey	cemerick: what's the default?
09:06	cemerick	rhickey: it's system-dependent -- the value of the file.encoding system property. "MacRoman" on my system right now.
09:07	rhickey	ick
09:07	cemerick	Given that, any strings that contain non-ascii unicode characters are generally read incorrectly. Either the reader needs to watch for a per-file encoding indicator in a special comment, or just default to UTF-8 (my vote, certainly).
09:08	rhickey	could you please post this on the group - I'm fine with it, but would like to get broader input first - thanks
09:08	cemerick	np
09:45	cemerick	rhickey: just out of curiosity, are you planning on accepting the PersistentStructMap patch I posted with the genbean impl?
09:53	rhickey	cemerick: done, rev 976
09:53	cemerick	rhickey: ah, thanks very much -- I figured you were still thinking about it :-)
09:54	rhickey	cemerick: no, I just didn't realize they were separate patches (not ready for genbean yet)
10:31	jykrd	would you say that clojure is easier to learn than, say, lisp or scheme, or harder?
10:49	arbscht	jykrd: for whom? between those three languages, I'd say it's subjective
11:06	jykrd	arbscht: for the beginner
11:10	arbscht	jykrd: I can't imagine that clojure is conceptually any harder than another lisp or scheme
11:10	jykrd	so probably just about the same then, eh?
11:10	cemerick	I'd say it's clearly easier to jump into than CL; it's probably on par with various schemes, though.
11:11	arbscht	considering the raw volume of documentation, and the fact that clojure is rapidly developing, maybe it is harder for a beginner to learn clojure right now. I don't know
11:11	Chouser	If you're used to other languages, the immutability of Clojure can be tricky at first.
11:12	Chouser	But it's so much smaller than Common Lisp, that's a huge help.
11:22	arbscht	even CL's mutability can be equally tricky for such a person
11:26	jykrd	yea, it's such a subjective question.. Especially when you try to compare the learning curve to something like python, ruby, or even java
11:32	jykrd	I'm already biased because I've already learned the way to work with those imperative language styles
12:02	jykrd	I think it's a good question, nevertheless. How early can we start teaching programming in schools? How conducive are the design of new programming languages to process of educating and learning in grade-school. I guess the axiomatic structure of lisp-like languages -- with higher constructs being built out of a small subset of constructs -- might lend itself to the methods of learning and education.
12:02	jykrd	You'd just have to get them early
12:24	Chouser	I think you're asking the education question the wrong way 'round. I want to know how I can best design education to teach prinicples that are needed in the best new languages.
12:25	Chouser	I've been mulling some kind of game or virtual play environment where kids could attach clojure code to objects and see how they interact.
12:26	Chouser	like logo, except functional instead of imperative.
12:27	jykrd	It was actually seeing scratch (http://scratch.mit.edu/) today that prompted my comment
12:29	Chouser	hm!
12:31	jykrd	this one is neat http://scratch.mit.edu/projects/Cyclone103/221614
12:34	cemerick	http://www.alice.org is pretty slick -- very smalltalk-ish
12:36	Chouser	scratch is cool, but looks pretty imperative. I really wonder if imperative is inherently simpler for kids to understand, or if it's just how most of us are used to programming.
12:38	jykrd	well, I think recursion is inherently more advanced than a sequential form
12:39	jykrd	but recursion, as a concept, by itself, I don't think is beyond the intellect of an elementary school kid
12:41	Chouser	yeah, I guess recursion is harder than a looping construct in a lot of cases.
12:41	jykrd	I'm not sure if immutability is inherently more unintuitive than mutability. I'm biased, coming from the mutable world.
12:41	Chouser	but with high-order functions, you can often do with no loop or recursion at all. I wonder how hard high-order would be for a kid.
12:42	slava	i find higher order functions easier than both explicit recursion and looping syntax
12:42	jykrd	But I still feel like my hands are a bit tied.. like I have a lot less options. that may change though
12:42	Chouser	also, I wonder if loop/recur could be taught or thought of in a way that doesn't really feel like rursion or carry the mental complexity of it.
12:43	jykrd	I still don't know what the canonical definition of "higher-order" is
12:43	slava	a function taking another function
12:43	slava	or returning another function
12:43	jykrd	I don't think that's necessarily harder for a kid
12:44	Chouser	One thing to consider about toy languages like logo or scratch is that you're capped -- once you hit its limit, you may have some concepts you can carry with you, but you're going to need a "real" language.
12:44	Chouser	That was a huge barrier for me when I learned BASIC very young, and it's one reason I'm curious to see what happens with some of these kids who are learning python.
12:45	jykrd	in the sense that python is a "real" language?
12:46	Chouser	yes, to the extent that it's got all the platform support and library selection you need to tackle any real-world problem.
12:46	slava	except for anything that requires performance
12:46	Chouser	networking, 3d graphics, web apps, GUI apps, etc.
12:47	Chouser	the resource-sharing community around scratch looks really good.
12:49	jykrd	"a function taking another function..." question: that's not the same thing as a function taking an object, is it?
12:49	jykrd	seems like a silly question
12:50	dudleyf	It can be, if functions are also objects
12:50	jykrd	I understand the difference, lexically, between a function and an object... but, numberObject.increment is a function, right?
12:50	Chouser	jykrd: you're not entirely off-base. In languages where functions are not themselves objects, you can accomplish something similar by taking an object that just has a single method named something like "run"
12:51	slava	jykrd: its best not to map everything back to java syntax
12:52	jykrd	so, a language where "everything is an object".. what about "everything is a function"
12:52	slava	lambda calculus
12:52	Chouser	jykrd: ok, so you have this person object -- what does it do if you call it?
12:53	jykrd	depends how you call it? person returns person?
12:54	Chouser	I guess my point is that some objects don't make much sense as a function, so "everything is a function" might not help you much.
12:55	Chouser	on the other hand, being able to treat functions like an object (pass them around, store them in a list, etc.) has lots of surprising and useful benefits.
12:56	jykrd	the comment about kids understanding higher-order functions is what prompted the line of thought
12:57	jykrd	if one didn't have differentiate, at the syntactical level, between primitives, objects, functions, would that make things easier to understand?
12:58	Chouser	that's one reason I think a lisp might be easy to teach -- no syntactic difference between anything. :-)
12:58	jykrd	agreed.
12:59	Chouser	my oldest isn't quite ready to learn such things, and hasn't shown interest anyway, but I'd like to have something to reach for when one of them finally wants to take control of the computer (if they ever do).
13:00	Chouser	I'd hate to send them on an imperitive or toy-language dead-end if there's any chance a better option would be accessible for them.
13:03	jykrd	well, there's always squeak (http://www.squeak.org/)
13:03	jykrd	oh wait.. looks like scratch is an offshoot of squeak :)
13:04	jykrd	I guess scratch has smalltalk underneath it
13:06	jykrd	bbiab
14:39	drewr	What's everybody doing with LOAD-FILE regarding relative paths?
14:41	cemerick	drewr: I understand that a relative file loading mechanism either exists in clojure-contrib/lib, or is planned.
14:41	cemerick	so far, we don't have any multi-file namespaces, so lib/use is sufficient
14:41	drewr	I would like to use lib.clj, but how can I bootstrap it without a known path somewhere?
14:42	drewr	This is the first time I've really tried to break out some clojure into a modular file structure.
14:43	Chouser	I think the "normal" way right now is to make sure lib.clj is in your classpath, and then use (clojure.lang.RT/loadResourceScript "lib.clj")
14:43	cemerick	drewr: Put a form like (. clojure.lang.RT (loadResourceScript "lib.clj") in a user.clj file in a top-level of your classpath.
14:44	cemerick	or that :-) (although the user.clj route ensures that lib is loaded right at clojure's init, and done only once)
14:45	cemerick	lib will become part of core clojure eventually, or so I've heard
14:48	Chouser	yeah, putting it in user.clj is probably a good idea. I don't user user.clj at all currently.
14:49	kotarak	I use it for lib and bye (= (. java.lang.System exit 0))
14:49	cemerick	The only downside to that is if your user.clj is shadowed by another user.clj in a jar file or directory further up the classpath. We may set things up so that lib.clj is loaded from Java, for those projects that are deployed elsewhere.
15:40	drewr	So, ADD-CLASSPATH followed by a loadResourceScript doesn't seem to work.
15:41	drewr	Does ADD-CLASSPATH manipulate something different than the "official" classpath?
15:42	rhickey__	drewr: it can only manipulate the loader use by Clojure, not the loader that loaded Clojure, which is what resolves loadResourceScript
15:57	cemerick	whoa, the ALL-CAPS thing is making my eyes bug out ;-)
15:59	drewr	cemerick: Sorry, but I prefer disambiguation.
16:07	Chouser	except that clojure is case sensitive, so it's not really the same thing. If we came up with some convention, I could use a different font and maybe even syntax hiliting in the web-based log.
16:07	Chouser	I've been mulling this for a while, and haven't come up with a single viable convention.
16:08	Chouser	<in-ns>, (in-ns), IN-NS, in-ns, CLOJURE: in-ns, (CLOJURE in-ns), etc. each have their own overwhelming drawback.
16:09	cemerick	is disambiguation in irc really a cause for concern?
16:10	drewr	I prefer to waste as little time as possible.
16:12	Chouser	drewr: if you know the classpath you want to add for loadResourceScript, can't you just use load-file directly?
16:12	Chouser	oh, you probably want to put it in a .jar. nm.
16:13	drewr	Chouser: I probably could for my current situation, but I'd rather have a generic way of doing it.
22:56	arohner	is anyone else having problems checking out clojure-contrib from sourceforge?
23:05	Chouser	yep, connection reset by peer