#clojure – 2008-07-17

2008-07-17

07:00	StartsWithK	hi
07:01	rhickey_	hey
07:01	StartsWithK	did any one created osgi bundle that can use clojure?
07:01	StartsWithK	i have no luck with creating one
07:01	StartsWithK	what i did is
07:02	StartsWithK	i created regular bundle (with scala, but its sam as java version)
07:02	StartsWithK	and in manifest file included Bundle-ClassPath: clojure.jar
07:02	StartsWithK	and included clojure.jar with my bundle
07:03	StartsWithK	i think RT class would be global to all bundles if it was registered as separate bundle
07:03	StartsWithK	bun when i try to call some method on RT i get..
07:04	StartsWithK	java.lang.ExceptionInitilizerError
07:05	StartsWithK	this happens in my Activator inside start method..
07:07	rhickey_	I don't know osgi, but it could be that RT can't find boot.clj etc in the classpath
07:08	StartsWithK	i even tryed to call something like RT.nextID ..
07:08	StartsWithK	is there a way for clojure to dump me some kind of log of what it is doing?
07:09	StartsWithK	hmm.. maybe it is that
07:09	StartsWithK	should i maybe copy all of clojure.jar files directly to my bundle?
08:08	rhickey_	I've changed eval so the stack traces should be much shorter and more relevant
08:35	cemerick	rhickey_: That's very exciting.
10:00	meredydd	http://pastebin.com/m4be0b624
10:01	meredydd	Ooo. And I look at scrollback, and see rhickey has addressed that issue too
10:28	Chouser	I've got rhickey's changes built, but I haven't tried them out yet.
10:29	rhickey_	try (+ "a" 2) before and after the change
10:36	Chouser	Anyone looked at Google's protocol buffers? "Order of magnitude faster than xml" sounds interesting.
10:36	Chouser	http://code.google.com/apis/protocolbuffers/docs/overview.html
10:37	rhickey_	ugh, IDL
10:40	rhickey_	Many people wish they had Google's problems, but they don't
10:40	Chouser	heh. good point.
10:41	rhickey_	I'm no fan of XML, but I would prefer optimizations oriented around - "here's the first set of tags, all the children will have the same set so I'll leave them out", which would still be dynamic
10:42	rhickey_	and XML closing tags are an abomination
10:43	Chouser	I guess I'm an XML fan if not a fan-boy. It's better than anything else I've heard of that acheived such broad acceptance.
10:44	abrooks	I continue to share some level of Brett's annoyance at the inconsistency between attributes and sub-tags.
10:44	Chouser	ASN.1 is no good. I've only heard bad things about DIF. etc.
10:46	Chouser	sure, there's plenty of things wrong with XML. But what's right: dynamic, namespaced, heirarchical, char-encoding-aware, widely used.
10:47	Chouser	I like JSON too for a lot of applications, but it's missing at least 2 of those.
10:47	albino	How is xml dynamic?
10:47	rhickey_	read/print
10:48	abrooks	Chouser: Have you presented the alternate Clojure XML representation?
10:48	Chouser	nope. It's not very different from a couple of formats people are knocking around, though.
10:49	abrooks	No, it's fairly similar but I think the difference is big enough that it should be considered.
10:49	rhickey_	[tag {attrs} children ...]
10:49	rhickey_	?
10:49	Chouser	rhickey_: yes
10:49	Chouser	I think we had some namespace ideas too
10:49	rhickey_	attrs optional?
10:49	abrooks	Yeah, I now need to disinter those dead brain cells to remember that.
10:50	abrooks	Yes, attrs optional.
10:50	abrooks	I think.
10:50	abrooks	Is that what we said?
10:50	Chouser	rhickey_: I want parse, zip, and emit support for that format. (and was planning to write it if nobody else did)
10:51	Chouser	abrooks: yes, optional attrs for input only
10:51	abrooks	^middle^end
10:51	abrooks	Chouser: Ah, that's right.
10:53	Chouser	rhickey_: compared to xml.clj, that's one less hash-map per xml element, and less verbose when printed.
10:54	rhickey_	Chouser: an early version (prior to checkin) used that format. It was one of the things that inspired subvec
10:54	rhickey_	I think it is ideal for human entry
10:54	abrooks	Why the change?
10:54	Chouser	rhickey_: does it have a drawback I'm missing?
10:54	rhickey_	programming with it, I found it a bit precarious, as it was easy to get the wrong bits of the data structure accidentally
10:55	rhickey_	you'd have to use access functions always
10:55	abrooks	Because of the need to conditionalize for the posibly absent attributes?
10:55	Chouser	xml.clj already provides accessors for tag, attrs, and content. I figured providing those would make it seamless.
10:55	abrooks	Off by one or two for the name and attribute slots?
10:57	abrooks	I think those issues are not so significant with the current set of tools. There's really not a need to touch the structure directly.
10:57	rhickey_	you get into a nested context and forget (content x) and use x, it's the same data structure
10:58	rhickey_	I'm not arguing against it, but that was my experience
11:00	abrooks	Chouser: Did we discuss [name {attrs} [content]]?
11:00	rhickey_	switching back was on my todo list, but I wanted to think about those issues
11:00	rhickey_	abrooks: I have pages and pages of variants, including that
11:00	abrooks	Less nesting is still probably better.
11:00	rhickey_	right
11:00	Chouser	abrooks: not that I recall. wouldn't really help rhickey's specific example.
11:01	rhickey_	Chouser: I don't think optional attrs for input only works
11:01	Chouser	oh?
11:02	rhickey_	turning [a b] into [a {} b] on people will be confusing
11:02	Chouser	I guess input only would have to be defined -- probably by requiring use of a normalize function or something.
11:03	rhickey_	plus you might read a huge structure which will need translation
11:03	Chouser	hm. if the accessors still work correctly? I would just rather not type [:p {} "This is " [:b {} "bold"]]
11:05	rhickey_	I'm arguing for the opposite, leave out empty {}s, attrs and content accessors have to test the type of (element 1)
11:06	Chouser	oh, arguing against the "input only" part. ok.
11:07	Chouser	I guess if you're already requiring the use of accessors, that's not a huge deal.
11:07	rhickey_	right, whatever data structure is acceptable input has to work without transformation
11:08	rhickey_	and will discourage (drop 2 element) to get at content
11:08	Chouser	another detail is that [[:tag ...] [:tag ...]] would be spliced in
11:09	rhickey_	?
11:11	Chouser	because I don't know how else to nicely splice in generated content
11:11	Chouser	[:table [:tr "heading row"] (for [r rows] [:tr r])]
11:13	rhickey_	user=> `[a b ~@(range 3)]
11:13	rhickey_	[user/a user/b 0 1 2]
11:13	Chouser	yeah. that's what webjure does
11:13	rhickey_	if you are a macro
11:16	rhickey_	Chouser: stiull not sure I get what you meant by [[:tag ...] [:tag ...]]
11:18	Chouser	[:p [:c1] [:c2] [[:c3] [:c4]] [:c5]] ... all the c's are siblings, :p is their parent
11:18	rhickey_	oh
11:21	Chouser	I don't love it, but so far I think I like it better than any alternative I've tried.
11:21	rhickey_	indefinitely nested?
11:22	abrooks	Chouser: I think that plays with my head and would lead to several easy-to-commit errors.
11:23	Chouser	rhickey_: hm. presumably, though I haven't needed more than one level yet.
11:23	abrooks	It does make merging easier.
11:24	abrooks	How about sequences? [:p [:c1] [:c2] ([:c3] [:c4]) [:c5]] ?
11:24	Chouser	abrooks: so suggest an alternative. webjure uses a backtick at the root of the s-expr, and then ~ or ~@ before every non-literla value.
11:24	Chouser	abrooks: sure, seq or vector. but not written like that.
11:25	abrooks	Oh, heh.
11:25	Chouser	[:p [:c1] [:c2] (list [:c3] [:c4]) [:c5]]
11:25	abrooks	[:p [:c1] [:c2] '([:c3] [:c4]) [:c5]] ?
11:25	abrooks	Hm. Not the same.
11:26	Chouser	that's good enough
11:26	Chouser	in this case
11:27	Chouser	the point is, vector hash-map and keyword syntax allow beautiful self-representation without quoting using ` or '
11:27	rhickey_	seqs/vecs don't matter, what matters is that the entry format be directly useful as data, so (content element) would have to call some sort of flatten
11:28	rhickey_	also, if you are looking for easy read/modify/emit, both seqs and vecs have bad insert-in-middle perf
11:28	abrooks	We can't really do this without macros...
11:28	abrooks	Or adding flattening functions which I think we agree are yucky.
11:28	Chouser	but as soon as you quote or use a macro, you lose all that and have to convert stuff in and out of the format.
11:29	rhickey_	we need to clarify what we are talking about here - templating systems are another level, first thing is how is xml represented as data
11:29	Chouser	you might as well then use symbols and lists instead: `(html (body ~this ~that ~@(stuff ...)))
11:33	Chouser	of course everyone's specific use cases are different, but when one situation I'm frequently in is one where I now reach for xslt/xpath.
11:33	abrooks	... and a bucket.
11:33	Chouser	xpath is ok, but xslt is annoying. I think I have a reasonable replacement for xpath in clojure, so I'd like to do my full round trip xml->parse->modify->xml in clojure
11:34	Chouser	right now, xml.clj -> zip.clj -> zip-filter.clj work nicely for the parsing and selecting.
11:35	Chouser	But in order to insert new sub-trees into my zip-tree, I need to generate xml.clj's structure.
11:36	Chouser	doing that with raw s-expr is verbose and error-prone (I set the :contnet of the element, why can't I see it?)
11:36	abrooks	All of these nits aside, I must say that Clojure's ability to reasonably represent and process XML in a native but isomorphically structured format is amazing. Every other language you hit places where you hold your breath, unpack the XML into something usable, process and, only at the end, restructure everything for output.
11:36	rhickey_	Chouser: ?
11:36	Chouser	I've suggest to poor Lau that he provide the new content as an string and run it through xml/parse. This works but is slow and has other caviats.
11:37	Chouser	abrooks: isn't that what we're doing in clojure?
11:38	rhickey_	Chouser: when you have (content e) -> [a b d e] and you want to make it [a b c d e] what do you want to do/say?
11:39	abrooks	Chouser: I don't mean on the bits level, I mean on the data structure level (or even above) -- how you relate and interact with the data.
11:39	Chouser	hm. well now that I've spewed all that, perhaps all I really want is something that consumes [:a {:href ...}] and produces {:tag :a, :attrs {:href ...}, ...}
11:39	rhickey_	heh
11:40	Chouser	then I can make up all the fancy input semantics I want (optional {}, nested seq content, etc.)
11:40	Chouser	I'm pretty bad at thining unless I'm talking. sigh
11:41	Chouser	thinking
11:41	abrooks	We don't have an (xml<- ...) yet do we? (We have (xml->) IIRC).
11:42	Chouser	abrooks: xml-> is from zip-filter, and it's -> in the sense of the builtin ->, not like C++ >> stream io or anything.
11:42	Chouser	abrooks: xml.clj provides parse and emit
11:43	abrooks	Richt. I was thining of (<- xml [:tag])
11:43	abrooks	Drat. There's that thining again. We must not be doing enough thinking.
11:45	Chouser	well, if I write a tmpl function as described above, you could say (xml/emit (tmpl [:tag]))
11:45	abrooks	Is Clojure SVN still sad? I'm not getting any response.
11:45	Chouser	and get <tag /> ...so much better. :-/
11:45	abrooks	Ah, no, wait... it's just horribly slow.
11:48	Chouser	I want to think more about xml namespaces too. They're powerful, but a lot of the APIs out there make them pretty painful to deal with.
11:49	abrooks	Isn't that what we were doing with optional attrs.
11:49	abrooks	?
11:49	rhickey_	abrooks: no, I mean supporting both vector (new) and map (as is today) elements
11:50	abrooks	Ah, I see. Multiple formats simultaneously based on object types.
11:50	rhickey_	Chouser: at least nested : is ok now
11:50	Chouser	rhickey_: yep, I look forward to taking advantage of that. :-)
11:52	Chouser	the problem is that you want a map of prefixes to namespace uris somewhere so that all your query and literal xml expressions can use the prefixes.
11:52	Chouser	so where do you put the namespace map without getting all stateful?
11:52	rhickey_	Chouser: I don't think the flatten required by your nested child seqs is too bad, since most reading is sequential
11:53	Chouser	rhickey_: I was just about to say that -- lazy-xml generates a seq instead of a vector for the content anyway, and zip and zip-filter still work great
11:56	rhickey_	an advantage to the canonic (current) xml data representation is that 'setting' the content is easier
11:56	rhickey_	so transformations of vector elements might yield map elements, but using accessors on wouldn't care
11:56	rhickey_	one wouldn't
11:57	rhickey_	Chouser: where do they go in xml?
11:57	rhickey_	namespaces
11:58	rhickey_	attrs?
11:58	Chouser	you can declare a namespace prefix association in any element, and it applies for that element and all descendants.
11:59	Chouser	they look like attributes
11:59	rhickey_	are they not?
11:59	rhickey_	in a DOM?
12:00	Chouser	<ns1:foo xmlns:ns1="namespace1">...</ns1:foo>
12:00	Chouser	um... good question.
12:01	rhickey_	also most DOMs will present the tags as qualified names for programmatic use
12:01	rhickey_	or at least make the ns available
12:02	rhickey_	so a ns aware parser could ns-qualify while keywordizing...
12:03	rhickey_	and an emitter could elide anything namespaces declared along the way...
12:03	rhickey_	setting aside read/print veracity
12:03	Chouser	SAX lists namespace declarations as attrs, though other parsers do other things.
12:05	Chouser	xpath and xslt associate the real namespace with each tag and attr
12:05	Chouser	I'm not sure what the w3 DOM does
12:06	rhickey_	applying the namespaces on read seems to be the right thing
12:07	rhickey_	getting rid of them on the way out is the trick
12:08	Chouser	sure. but even "apply the namespace" isn't obvious to me.
12:08	Chouser	Or I guess what I mean is, what's the canonical format?
12:08	rhickey_	:ns:name
12:09	Chouser	except an ns looks like http://www.w3.org/1999/xhtml
12:09	Chouser	you don't want {:tag :http://www.w3.org/1999/xhtml:img ...}
12:10	Chouser	I guess you could do {:tag :img, :nsmap {nil "http://www.w3.org/1999/xhtml"} ...}
12:10	Chouser	...and then have the nsmaps apply to children, just like raw xml does. But then those children lose meaning when taken out of context.
12:10	Chouser	(this is what I meant by "where to put the ns map")
12:11	rhickey_	if you don't end up with the ns on the tag somehow, everyone will have to track the namespaces, there isn't one map as it can change in nested contexts
12:12	rhickey_	if I see :img in the middle of the document, how do I know which :img?
12:12	Chouser	right. the same question applies to :xhtml:img -- which xhtml?
12:13	Chouser	in practice, most documents don't stack their nsmaps very much. you tend to declare them in the root element and leave them alone.
12:13	rhickey_	but programmatically you can ask img for its ns and get http://www.w3.org/1999/xhtml
12:13	rhickey_	anywhere, with no lookup table
12:13	Chouser	how? I don't follow.
12:14	Chouser	I mean, we need to provide a way to do that, but I don't see how to best store that information.
12:14	rhickey_	when you load that into a dom and ask the element for its ns you get the whole gnarly thing
12:14	rhickey_	metadata, except none for keywords...
12:14	Chouser	:-)
12:15	Chouser	right, because remember each attr has a namespace as well
12:15	rhickey_	yes, all names
12:16	Chouser	it's also beneficial to store the prefixes used on input somewhere. there are a lot of almost-correct xml tools that panic when you use an unexpected prefix
12:17	Chouser	they want <rss:entry xmlns:rss="...rss..."> not <n1:entry xmlns:n1="...rss...">
12:18	rhickey_	I don't think we'd be making up prefixes
12:18	Chouser	maybe it would work for every element to have an :nsmap, and mostly they would all be the same hash-map
12:18	rhickey_	maybe swapping in full qualifiers
12:19	Chouser	if you hit a stacking case on input, the subtree of elements will all be pointing to a second hash-map
12:19	rhickey_	something does that... some Scheme thing?
12:19	cemerick	I'm totally lurking here, and a long way from the days when I swam in XML, but it seems that conforming to XML Infoset would be a #1 priority. Syntax and such are definitely important, but the data model needs to be right...otherwise, impedance ramps up quickly when serializing, etc.
12:26	rhickey_	http://okmij.org/ftp/Scheme/SXML.html
12:29	rhickey_	emulated here: http://groups.google.com/group/clojure/browse_frm/thread/ce8131bd1ae59bfc/437c0119d2c91628?#437c0119d2c91628
12:32	cemerick	yeah, SXML looks like a good starting point.
12:33	cemerick	I only brought up infoset because it was what led me to sanity after running into some very hairy technicalities w.r.t. namespace handling in various contexts. There be dragons.
12:34	cemerick	(or, some degree of sanity; IIRC, there are some edge cases where some key XML specs are in conflict and/or ambiguous w.r.t. namespace handling)
12:37	Chouser	ok, so sxml attempts to handle namespaces though that clojure version doesn't?
12:38	cemerick	Chouser: yeah, that's listed as one of the to-do's in the code
12:38	Chouser	ah, indeed.
12:39	Chouser	I don't really understand what sxml is doing, though.
12:39	Chouser	"If an application told the parser how to map http://www.cars.com/xml, the application can keep this mapping in its mind and will not need additional reminders."
12:41	Chouser	it seems to list details in an element's (@ ...) list, but it's not clear to me if that's actuallying being returned or not
12:41	Chouser	huh. http://www.cars.com/xml:part is a valid scheme symbol.
12:47	cemerick	Rich's sxml link was the first I've heard of it, but it seems that he's talking about application-registered namespaces.
12:48	cemerick	Which can be handy in situations where you need to combine documents that have conflicting namespace aliases.
13:53	rhickey_	user=> (namespace 'http://www.cars.com/xml/part)
13:53	rhickey_	"http://www.cars.com/xml"
13:55	rhickey_	user=> (name :http://www.cars.com/xml/part)
13:55	rhickey_	"part"
14:15	cemerick	rhickey_: shouldn't that be :http://www.cars.com/xml:part?
14:16	rhickey_	not in Clojure, namespace is everything before last /
14:16	rhickey_	this way you can get at the parts with namespace and name
14:17	rhickey_	on emit can be changed to :
14:20	cemerick	oh, I figured you were using some functions in some xml ns you were working on. Clever bit, reusing the built-ins.
14:21	rhickey_	still trying to encode xml in native data structures, here symbols or keywords for identifiers
14:23	rhickey_	when working with xml esp rdf, it is a huge pain when systems create a composite identifier with no ability to split ns and name
14:24	cemerick	yes, definitely
14:43	Chouser	rhickey_: do you think the whole universal name should be used for every tag and attr name in the internal structure?
14:44	rhickey_	Chouser: I don't know, but it's now an option
14:44	Chouser	:-) ok.
14:45	rhickey_	other options are to use symbols, with namespaces in the metadata (:ns ^(tag e))
14:46	Chouser	symbols are interned, but their metadata wouldn't be, is that correct?
14:47	rhickey_	one problem is that 'by hand' xml data would still need to be 'parsed' to get the qualification
14:47	cemerick	semantically, namespaces are definitely not metadata (at least how clojure conceives of metadata)
14:47	rhickey_	Chouser: if the names are symbols or keywords, the strings are interned, ns meta maps can be shared as you described before
14:47	rhickey_	cemerick: true
14:48	rhickey_	attrs could be considered metadata, but xml really leaves the semantics open
14:49	cemerick	I mean, clojure metadata is a thoroughly convenient mechanism for name metadata. FWIW, I often wish there were parallel metadata tracks in clojure -- one for the current notion of metadata, and one that is considered part of a value.
14:50	cemerick	(not that I don't abuse that mechanism for my own purposes, anyway ;-) )
14:51	rhickey_	cemerick: is considered for equality or something more?
14:56	cemerick	equality for sure, but other things too, I'm sure. Having that other metadata print (with pr, etc) would be super-handy.
14:57	rhickey_	print-meta controls meta printing
14:57	cemerick	I've got a prn-with-meta fn that gets the job done with the current metadata, so it's not a big deal.
14:57	cemerick	Hah!
15:22	StartsWithK	hi
15:22	StartsWithK	so i was trying to create this osgi bundle with clojure
15:22	StartsWithK	and i have no luck
15:23	StartsWithK	whatever i do i get that java.lang.ExceptionInitilizerError
15:24	StartsWithK	did any one created osgi bundle with clojure?
15:25	StartsWithK	it seams that clojure can't find boot.clj, it throws same error if i remove boot.clj from clojure.jar and try to run in
15:26	StartsWithK	i don't know is this important but i use Knopflerfish as osgi container
15:27	cemerick	sounds like a classloader issue
15:28	StartsWithK	yes it looks like it is
15:28	StartsWithK	so ill just dump all experiments i did so far
15:29	StartsWithK	included clojure.jar in my bundle.jar and used Bundle-ClassPath: clojure.jar
15:29	StartsWithK	included files from clojure.jar in my .jar
15:29	StartsWithK	added Bundle-ClassPath: .
15:29	StartsWithK	and copied all .clj files from clojure.jar to directory where my .jar is located
15:30	cemerick	well, I don't know how Bundle-Classpath works, but if you want to merge Clojure in with your jar, you need to put everything from clojure.jar into your jar
15:30	cemerick	the .clj files, too
15:30	StartsWithK	i did that too
15:30	StartsWithK	same thing
15:31	cemerick	OK, so your jar's top level has the clojure classfile dir, yes?
15:31	StartsWithK	yes
15:31	cemerick	the .clj files should be at that top level as well
15:32	StartsWithK	ther are
15:32	StartsWithK	they*
15:32	cemerick	Well, it should work. :-) boot.clj is loaded using the same classloader that loaded clojure's core runtime class(es)
15:32	StartsWithK	hmm
15:32	StartsWithK	i wish it worked :)
15:33	cemerick	hrm, try putting the clj files in clojure/lang in your jar
15:34	StartsWithK	ok
15:43	StartsWithK	same thing happens
15:44	StartsWithK	at this point i have .clj in my jar, inside clojure/lang in my jar, clojure.jar in my jar and all .clj files in directory where my jar is located
15:44	StartsWithK	its not picking up on any of them
15:45	StartsWithK	also, this code work outside of osgi container.. i can run it as standalone just fine
15:45	cemerick	well, the last thing you mentioned wouldn't ever work. The 2nd and 3rd things should definitely work (modulo the operation of Bundle-Classpath
15:47	StartsWithK	ill create minimal example, using java instead of scala.. but there should not be any difference there
15:51	cemerick	Nevermind, the first option should be the one that works (I just re-noticed that '/' is prepended to all paths being loaded at init).
16:22	StartsWithK	hmm.. same thing
16:25	StartsWithK	if i run it again, without reintalling the bundle
16:25	StartsWithK	i get
16:26	StartsWithK	java.lang.NoClassDefFoundError: Colud not initialize class cljure.lang.RT
16:46	StartsWithK	For the OSGi import/export mechanism to work,
16:46	StartsWithK	the bundle must use the Bundle classloader.
16:46	StartsWithK	o! However, many libraries uses the system
16:46	StartsWithK	classloader or the thread's classloader
16:46	StartsWithK	o! Works great in standalone apps
16:46	StartsWithK	o! Does not work at all in typical OSGi settings
16:47	StartsWithK	from knopflerfish presentation about bundling existing applications as osgi bundles
16:47	StartsWithK	and i see that DynamicClassLoader is using thread's
16:51	cemerick	StartsWithK: well, NoClassDefFoundError is much different than the initializer exception you mentioned earlier
16:56	StartsWithK	cemerick, yes it is, but that is from second call to bundle's start(), so if RT's static {} field faild to execute first time that could be why i see that message second time i try to start the bundle
17:08	cemerick	StartsWithK: could you paste a full stack trace?
17:08	StartsWithK	cemerick, here is no stack trace at all
17:09	StartsWithK	just that one message that is shown inside knopflerfish admin gui
17:09	StartsWithK	i mean, there is stack trace but it starts with kf gui and only last entry is for my bundle
17:09	cemerick	have you checked your log files? The stack trace must be printed out somewhere.
17:10	cemerick	You might have to turn on osgi debugging, etc., in order to get the original stack trace
17:10	cemerick	That is, if clojure.lang.RT is being found, but is causing an error during initialization.
17:13	StartsWithK	oh.. i didn't turn all debug options inside kf.. ill try with all of them on
17:24	meredydd	Hmm..any suggestions for:
17:24	meredydd	java.lang.Exception: Unable to resolve symbol: in this context
17:24	meredydd	Didn't think you could have an empty symbol :)
17:25	meredydd	(Just to be helpful, it's giving me no line numbers at all)
17:25	meredydd	(or even a file)
17:25	Chouser	meredydd: is this with the new easier-to-understand stack traces?
17:26	rhickey_	any more stack trace than that?
17:26	meredydd	Chouser: Yep. It's a compiler thing, though, so it's probably not part of the rejig.
17:26	meredydd	rhickey_: Sure, one sec
17:27	meredydd	http://pastebin.com/m7b2cc513
17:28	meredydd	Nice. Is this that XMPP library you're playing with?
17:28	rhickey_	yeah
17:28	rhickey_	I have a repl going through gtalk and jabber.org
17:29	meredydd	Much less elegant, and less XMPP.
17:29	meredydd	Any enlightenment on the compiler error?
17:31	rhickey_	meredydd: sure looks like you have a blank symbol somewhere
17:31	meredydd	The mind boggles. How does one write a blank symbol?
17:31	rhickey_	any symbol-creating macros in there?
17:32	meredydd	Uhh...doing what?
17:32	meredydd	I have one or two that use #
17:32	Chouser	meredydd: You have to delete the line where you do: (symbol "")
17:32	meredydd	and I think the odd (gensym), before I found out about #
17:32	rhickey_	(symbol "") or equivalent
17:32	Chouser	;-)
17:32	meredydd	Oh. No.
17:33	meredydd	Hmm. I am, however, using 'lib
17:33	meredydd	which probably does do some interesting symbol-bending behind the scenes
17:36	meredydd	...and it appears to have gone away again. Which is odd.
17:37	meredydd	I was sure I'd restarted the REPL after the update to svn HEAD. Perhaps my mind is playing tricks on me.
17:38	rhickey_	meredydd: I put up a patch which wraps the body of analyze, so you should get a line next time
17:38	meredydd	Thank-you.
17:38	meredydd	Do I get a filename as well?
17:38	rhickey_	yup
17:38	meredydd	ta
17:41	rhickey_	now I can write a coy "Little Clojurer" book with the code in iChat bubbles
17:41	meredydd	Someone's having fun :)
17:43	StartsWithK	cemerick, http://pastebin.com/m560b7301
17:43	StartsWithK	this is with copy of clojure inside my jar, .clj files are both in root of my jar and in clojure/lang
17:45	StartsWithK	thats it, no error message inisde debug log, only in kfish popup window
17:45	meredydd	rhickey_: Would it be possible, when method invocations go via reflections, to wrap the method call in a try-catch block for InvocationTargetException and re-throw the original (causal) exception?
17:46	rhickey_	no, but it could be peeled off in the repl
17:46	meredydd	The causal exception has the full backtrace any Clojure programmer is looking for - from our PoV, the InvocationTargetException amounts to an implementation detail
17:47	meredydd	Is there a particular reason you're not willing to peel off InvocationTargetExceptions in all cases? (I'm guessing it's going to be a performance thing)
17:48	rhickey_	and code gen size
17:50	meredydd	Hmm...theoretically, one might move reflected calls into RT, but I guess that's an extra-stack-frame penalty you don't want either
17:50	meredydd	I have no intuitive feel for how slow reflection is, so I don't really know how much it would cost in relative terms.
17:52	rhickey_	I take all that back, the calls go through Reflector so I can just change that rather than each gen point...
18:02	rhickey_	meredydd: done - so no error reporting complaining for 1 week :)
18:03	meredydd	Yay!
18:03	meredydd	(although if you want me to stop yelping when I stub my toe on something in the language, I fear a +b might be the only effective approach.)
18:04	rhickey_	just kidding, I like improving Clojure
18:04	meredydd	In all seriousness, though, from what I've seen, your stack-tidying, and now this together, look like the silver bullet.
18:05	meredydd	My stack traces actually tell me where in my code I was when I screwed up, and do so fairly concisely.
18:06	rhickey_	I'll grant completely that my first priority was making correct code work correctly, error handling will improve with time, but dynamic langs always have some more room for errors
18:08	meredydd	Absolutely, I agree with the emphasis. But I was having to grovel through three-deep stacks of InvocationTargetExceptions, checking the trace at each level to see whether my filename was there at all
18:08	meredydd	which got a bit wearing after a while.
18:08	meredydd	But no longer!
18:37	mebaran151	I'm playing with Clojure and I was wondering if there was an easy way to declare a main method so I could easily launch my app from the Netbeans idea
18:39	mebaran151	also are there any good ideas as to how write servlets with clojure: should I just define one generic servlet and route everything through it, hitting associated functions?
18:47	mebaran151	eerie silence ...
19:17	cemerick	mebaran151: There's no main methods per se -- use clojure.lang.Script to bootstrap a .clj file whose top-level forms do what you'd want from a "main method"
19:18	cemerick	StartsWithK: I don't see any errors there -- looks like the BundleClassLoader (whatever that is) is finding everything, including .clj files
19:18	StartsWithK	cemerick, yes, it looks like that
19:19	StartsWithK	but i am not even trying to execute any code from my test
19:19	StartsWithK	only call RT.nextID()
19:19	cemerick	And the UI shows an exception?
19:19	StartsWithK	yes
19:20	StartsWithK	maybe i should try with alternative osgi container
19:20	cemerick	I don't know. Try deploying a java-only (no clojure) app to knopflerfish, where all it does is try to load a file from the jar you deploy (i.e. using class.getResourceAsStream)
19:20	cemerick	or, yes, try another container
19:21	cemerick	I know people are using clojure within eclipse, which I think uses osgi pretty pervasively
19:21	StartsWithK	using clojure to write eclipse plugins?
19:22	cemerick	that I'm not aware of, but I'm pretty sure eclipse uses osgi "stuff" to bootstrap apps when debugging, etc
19:22	StartsWithK	my other option is equinox
19:22	cemerick	(so as to support "hot" code reloading, etc)
19:22	StartsWithK	yes, they have equinox as there osgi implementation
19:22	cemerick	otherwise, try to find out from the knopflerfish folks how to get the details of that stack trace, because it's not showing anywhere in the logs
19:23	StartsWithK	its second day i am trying to use kfish.. and not impressed in general
19:24	cemerick	well, if eclipse is using equinox, then it seems like a safe choice
19:24	StartsWithK	gui starts in 2-3 mnues before i can even see bundles..
19:24	StartsWithK	well, thats it for today
19:25	StartsWithK	thanks for help.. ill continut this tomorow
19:25	cemerick	StartsWithK: np
19:29	mebaran151	cemerick: is that a Java class or something?
19:33	cemerick	mebaran151: Yes, clojure.lang.Script is a Java class
19:33	cemerick	mebaran151: for example, java -cp clojure.jar clojure.lang.Script yourfile.clj will load yourfile.clj and exit
19:34	mebaran151	ah so it should just be in the startup script
19:35	mebaran151	I'm trying to figure out how to get Clojure integrated into my servlet workflow too, so any pointers on that would be appreciated. Right now, I'm thinking of building a generic routing servlet that would dispatch to function matched in a hashmap. Is this the cleanest way to work with servlets in clojure?
19:36	mebaran151	the only problem with it being scripted that way is that I can't set netbeans just to run my app...
19:40	cemerick	mebaran151: that certainly sounds like the simplest way to do it. I'm not really a web programmer, though.
19:41	cemerick	well, you'll want to gen-class your actual servlet, and then put the implementation of the servlet in clojure, and deploy the whole thing to tomcat, etc. Netbeans should be able to load that up without a problem.
19:42	cemerick	you'll want to read this: http://clojure.org/api#gen-and-save-class
19:42	cemerick	g'night all
20:32	mebaran151	how do I set up the path in which closure searches for other namespaces
20:32	mebaran151	to import functions from
20:41	mebaran151	anyway to setup some sort of env file for a project so that aquamacs automagically picks up the libs I dump in lib and the cljs I keep in src
20:44	Chouser	You can use load-file to load a .clj file, and then refer so you don't have to use a full namespace each time you call a function from that .clj
20:44	rhickey	mebaran151: there might be something in contrib, right now Clojure proper just has explicit load-file. user.clj will get auto-loaded, and you could put some logic in there to load all the cljs from a directory. As far as 'libs', are you talking about jars?
20:45	mebaran151	I need to use a couple jars from jetty
20:45	mebaran151	so load-file is probably somewhat similar to ruby's require semantics?
20:46	rhickey	mebaran151: no, but there is require in the lib.clj from contrib
20:47	rhickey	jars are subject to Java classpath, which unfortunately doesn't let you put a dir in the classpath and jars in the dir - each jar must be in the classpath
20:49	rhickey	Clojure has add-classpath, but that should only be used temporarily to grab a jar you forgot - there are limits to the visibility of classes loaded that way
20:49	mebaran151	ah I see
20:49	mebaran151	what's contrib
20:49	mebaran151	I just started playing with Clojure today when I got sick of Scala's oh so mutable data structures
20:51	rhickey	contrib is an incubation project for extensions to Clojure, some nice things there: https://sourceforge.net/projects/clojure-contrib/
20:56	mebaran151	what does the clojure/refer clojure mean?
20:57	mebaran151	thanks for all your help by the way: doc on closure is much to scattered....
20:57	rhickey	mebaran151: everything is covered on the API page in one place if you haven't seen that yet
21:00	rhickey	refer is the way you pull names into your namespace. A new namespace doesn't even have Clojure's public vars yet, so the use of refer itself has to be namespace qualified. (clojure/refer 'clojure) pulls in the core clojure names, after which refer, e.g., can be used without qualifier
21:00	mebaran151	oh I see
21:02	arbscht	speaking of the api, have you considered hyperlinking each entry in the api to the reference page it is also described in?
21:02	koneill	mebaran151: if git is your poison there is a clone of the contrib project available from git://github.com/kevinoneill/clojure-contrib.git
21:03	mebaran151	so how would I include it? just dump it in lib and set up my user.clj to figure it out?
21:05	rhickey	arbscht: at some point the redundancy between the two will be removed, so there won't necessarily be a place in the reference for each fn. There aren't already for many. I will try to go the other way as fns are referenced.
21:06	mebaran151	btw, does anybody here work with the Netbeans plugin? Can it reference the code in the buffer I'm working on?
21:07	rhickey	mebaran151: I haven't used the lib stuff, but I imagine if you have user.clj explicitly load lib.clj, then you can use its require to get classpath-based logical-name loading from there