#clojure – 2008-12-09

2008-12-09

03:20	Lau_of_DK	Morning gents
03:24	AWizzArd	what wiki software does clojure.org use?
03:44	oudeis	AWizzArd: a quick glance at the code suggests it is http://www.wikispaces.com/
03:46	AWizzArd	Ah oki, thx
04:25	danlarkin	ooof, nesting syntax-quote inside syntax-quote gets tricky fast
08:49	AWizzArd	Is there already a clojure lib for swing?
08:50	arbscht	AWizzArd: clojure can use swing directly
08:50	AWizzArd	yes, but I would not want to do it this complicated way. For example when I want to add an event handler for buttons.
08:51	AWizzArd	Why should I use (proxy ...) for that?
08:51	AWizzArd	(swing-add-handler my-button (fn [..] ...))
08:53	AWizzArd	Not that it is difficult to write. I was just curious if someone with swing knowledge did that.
08:56	blackdog	i'm curious if anyone's doing a javafx clone api
08:56	gnuvince	AWizzArd: as far as I know, no. And I am not sure a lot of people consider it a priority. There was an interesting exchange between Rich and Slava Pestov of the Factor language on Reddit a few months ago where Slava deplored the lack of language-specific idioms in Clojure. Rich replied that saying (.close fd) instead of (close fd) was not a big deal and that the real important thing was to be able to Get Things Dones (tm)
09:02	AWizzArd	Yes, I agree with that. What I have in mind would probably be 50-250 LOC of Clojure code. Just a simple helper tool, to make Java (and interop) pain go away. Definitly this is nothing for Rich to do, as it is really not very important for Clojure.
09:14	RSchulz	AWizzArd: Wouldn't your (swing-add-handler ...) be forced to proxy a local type to match the type required of the particular Swing handler?
09:15	RSchulz	I mean, that's probably a good thing to have in a helper, but proxying is unavoidable when interoperating with existing Java APIs, right?
09:15	AWizzArd	yes probably, I didn't look deeply into it yet
09:15	AWizzArd	yes
09:15	AWizzArd	the helper would do this proxy stuff though and hide it from us
09:15	RSchulz	Right. I think that would be pretty helpful.
09:16	RSchulz	Has anybody ever used MPW? Do you know what its Commando utility was?
09:16	AWizzArd	I'll see if I can get something like that ready, as I will need to do a little bit of Swing anyway.
09:16	RSchulz	It was a simple way to defining parameter-gathering dialogs for invoking CLI tools (within MPW).
09:16	RSchulz	I was thinking my CLI-phobic end users would like to have such dialogs, but writing them all by hand would be very tedious for me without such a DSL.
09:17	RSchulz	Also, it would get me out of my current Unix (Linux) requirement for the CLI tools.
09:24	AWizzArd	what do you prefer? (.method obj arg1 arg2) vs (. obj method arg1 arg2)?
09:25	RSchulz	I'm not sure I have strong preference. Probably the first, since it's more Lisp-like: (functor args...)
09:25	AWizzArd	yes
09:26	gnuvince	The first form is preferred.
09:31	Chouser	RSchulz: are you familiar with the library of ant tasks?
09:32	RSchulz	No. You mean the ones built into Ant?
09:32	Chouser	yes
09:32	RSchulz	I try to minimize my exposure to build.xml files...
09:32	RSchulz	I can never modify one without consulting the Ant documentation.
09:33	RSchulz	I can't usually get it right the first time.
09:33	Chouser	I only know what I've read in Stuart's book, it looks like they have a bunch of OS-indepedent operations that might be good candidates for wrapping in a dialog box.
09:34	Chouser	The book has a running example of building a DSL in Clojure so you can write build processes for ant without touching any XML.
09:35	RSchulz	Ah. Right. I actually looked at his ... what was it called? ... Ant DSL for ideas about another DSL I need to write.
09:35	Chouser	Lancet
09:35	RSchulz	Right. Lancet. I kept thinking "enchantment."
09:36	Chouser	It's still not clear to me if he made up the specs and name just for the book, or if it's some kind of re-implementation of some other "lancet".
09:37	RSchulz	I think he did it for the book. There were some messages about it on the mailing list.
09:40	clojurebot	svn rev 1148; support :when and :while together in for, patch from Chouser
09:41	AWizzArd	thumbs up
09:41	Chouser	handy!
09:41	AWizzArd	very
09:41	RSchulz	You name in lights!
09:41	Chouser	ah, yes, that too. :-) but I meant clojurebot announcing.
09:42	AWizzArd	Chouser: why are the dots in front of add, setSize and so on left out at http://clojure.org/jvm_hosted
09:44	Chouser	AWizzArd: that's old-style 'doto'. Much of the site documents the release (where that syntax is correct) rather than SVN.
09:44	AWizzArd	oh right, for the downloadable clojure.jar, this old one
09:45	RSchulz	Rich mentioned that the API page, http://clojure.org/api, is generated from the source code, so it remains up-to-date, though no more detailed than what you get from (doc ...)
09:54	whidden	What is the process for generating the API page and would it be "easy" to do for a local copy? -- for long tain rides.
10:02	RSchulz	I don't know. I'd start by looking at the Clojure build.xml file. If it's not there, ask Rich.
10:02	RSchulz	I'd like to get the text flowed, for one thing. And I'd like a more printer-friendly format for that page (no sidebar TOC, e.g.)
10:02	whidden	Ok I'll look into the build.xml when I have a free moment..
10:03	RSchulz	I suppose someone will write a ClojureDoc at some point.
10:06	Chouser	whidden: there is this: http://clojure.googlegroups.com/web/manual.pdf
10:06	Chouser	though that's a bit out of date by now, I suppose.
10:08	rhickey	RSchulz: there is a print stylesheet - I don't get sidebars etc when I say print
10:08	RSchulz	Really?? Huh. How long has that been the case?
10:08	RSchulz	Is Tom around?
10:09	RSchulz	Anyway, that's great. But without allowing the doc text to flow, there's still a lot of wasted space and it takes too many pages.
10:09	Chouser	For nearly a month now: http://clojure-log.n01se.net/date/2008-11-13.html#14:29b
10:10	RSchulz	Ah. Fabulous. I was hoping I hadn't just hallucinated the last time I tried printing (or print previewing).
10:11	RSchulz	Right now, it would be 41 pages for me (according to Firefox's print preview).
10:11	stuarthalloway	Chouser: A lancet fluke controls the mind of an ant. Dan Dennett talks about it at: http://blog.ted.com/2007/07/dan_dennett_on_2.php
10:11	RSchulz	That could probably be cut nearly in half if the doc text flowed.
10:11	Chouser	stuarthalloway: ha! great.
10:12	RSchulz	Yikes. Biology is gruesome.
10:13	rhickey	RSchulz: text not flowing on API page is my bad from last time I generated it. It flows on other pages for me when printing
10:14	stuarthalloway	The other Ant-mind-controlling organism is a Cordyceps fungus. There is stunning time-lapse video of Cordyceps in the BBC's Planet Earth series. It's even cooler than a Lancet fluke but I decided it was too hard to spell.
10:15	RSchulz	OK. Then I'm happy. (Don't shoot me, but I like paper documentation...)
10:15	rhickey	actualy looks very screwy - get through ns are all underlined for me...
10:16	rhickey	I'll try to regen later
10:17	RSchulz	OK, thanks. No particular hurry.
10:17	RSchulz	I'm not seeing that. It's usually a missed close tag, obviously.
10:18	rhickey	No, it's some wiki markup thing, that's what I generate
10:20	tomhickey	rhickey & RSchulz: I just got caught up on the discussion, let me know if i need to update anything
10:20	Chouser	rhickey: the code that generates the wiki markup isn't available anywhere, right?
10:20	Chouser	That question came up last night.
10:21	rhickey	Chouser: I should put it somewhere since I keep losing it :) Then finding and using broken old versions
10:21	Chouser	heh
10:23	rhickey	That's really old
10:26	lisppaste8	rhickey pasted "wiki doc gen" at http://paste.lisp.org/display/71857
10:27	rhickey	Probably broken, given the lack of wrapping (should remove non-double newlines), plus the underline thing - help welcome
10:28	RSchulz	rhickey: What did you think of the patch proposed to allow doc strings in defmulti? Chouser was the only one to respond, noting the potential breaking nature for some existing defmulti applications.
10:30	stuarthalloway	rhickey: FYI when I wrote the multimethods chapter, the number of (visible open source) multimethods that dispatched on anything other than type was vanishingly small, so now's the time for any breaking changes
10:32	AWizzArd	you mean the dispatch function was class ?
10:32	stuarthalloway	right
10:32	AWizzArd	ic
10:33	rhickey	class-or-tag will become prevalent
10:33	stuarthalloway	and most of the ones that weren't on class were on other things that server similar purpose, e.g. dispatch on identity to match keywords
10:33	rhickey	then people will start figuring out hierarchies and multi-argument dispatch. It's early days and people are doing the common thing
10:34	rhickey	I don't see why defmulti doc strings can't be done in a non-breaking way
10:36	rhickey	though changing default from positional to :default foo would be more extensible
10:40	rhickey	no one saw the sneak peak at streams in this? - http://groups.google.com/group/clojure/msg/53227004728d6c54
10:40	Chouser	I did. I love it.
10:41	rhickey	still working on timeout handling, since I want these to work well over queues
10:41	Chouser	all this agent/stm stuff is nice -- an insurance policy against the future. But it's the immutable collections and seq stuff that mean something to me today.
10:42	rhickey	I like timeout dynamic var, and (with-maximum-timeout 1000 ...)
10:42	tomhickey	rhickey: the wiki markup for gensym currently on site doesn't match what's coming back when i run your code (extra double underscores causing unclosed <u>)
10:43	Chouser	does 'stream' build a mutable iterator-type-thing over coll?
10:44	rhickey	Chouser: yes, a stream generator - next! is a one-shot read
10:44	rhickey	eos is a sentinel
10:45	rhickey	the key diff with iterators is that iterators have a built-in race condition: hasNext/next
10:45	rhickey	not so these generators
10:45	rhickey	means you can multiplex them
10:45	Chouser	ah, so you solved the 'map' problem?
10:46	rhickey	there's still the inversion of control issue, but having banged my head against it a good bit, I'm unconvinced that LFE for resource management is any easier than with-open
10:47	rhickey	and with-open could easily handle multiple reasource, and yes, map for streams multiple streams
10:47	rhickey	in any case, I'm shooting for a simple protocol
10:48	rhickey	The trick is to avoid duplicate effort - every seq fn should have a stream version, so I want the former to be mechanically generated from the latter
10:50	RSchulz	The only thing I can (quickly) find for LFE is Lisp Flavoured Erlang. Is that what you meant?
10:51	lisppaste8	rhickey pasted "more stream teasers" at http://paste.lisp.org/display/71858
10:51	Chouser	Left something Enumerator, I think.
10:52	rhickey	RSchulz: left-fold enumerators - http://okmij.org/ftp/Streams.html#iteratee
10:52	RSchulz	Thanks.
10:52	rhickey	esp: http://okmij.org/ftp/Haskell/Iteratee/DEFUN08-talk-notes.pdf
10:54	rhickey	outstanding issues are: what to do with a timeout - exception or return sentinel, and naming - should map et al be overloaded for streams or have map-???, filter-??? etc
10:55	RSchulz	If you write individual xyz-??? calls, they can be unified under a multimethod, right? But if you write them as a multimethod, they cannot easily be used directly? (Splitters vs. Lumpers)
10:56	Chouser	is the fn given to 'stream' guaranteed to get an (eos?) => true to handle resource cleanup?
10:57	rhickey	RSchulz: not sure what you mean, I'm just talking about (map f x) doing something special if x is an IStream
10:58	RSchulz	Isn't a type check an indication you should be using a multimethod?
10:58	rhickey	Chouser: the fn given to stream is responsible for producing an eos, if it's not an infinite stream
10:59	rhickey	RSchulz: how it branches isn't relevant at this point, the overloading vs non, e.g. map-stream, is the issue
11:00	rhickey	streams are actually very dangerous things to share, so it's nice to have their use called out. But inside a pipleline they can speed things up significantly
11:00	Chouser	Isn't the resource management issue about the flow of "I'm done" messages from stream consumers down into stream producers?
11:00	RSchulz	But that's the point. If you write map-stream it can still be unified through a multimethod and remain open to extension. But if you bury that inside map, it's no longer open.
11:00	RSchulz	Or am I still missing the point?
11:01	Chouser	RSchulz: if we're ever allowed to write code that uses 'map' on a stream, any change to that would be a big breaking change.
11:01	rhickey	right, it's an API thing
11:01	Chouser	regardless of how its implemented
11:02	Chouser	hm, and putting it that way sounds like an argument for starting with them called out as 'map-stream'
11:02	RSchulz	Which, I think, is my point.
11:02	Chouser	if it becomes obvious later that 'map' should be able to handle streams, that would be a non-breaking change.
11:02	Zephtar	I think a better approach would be a func that lazily turned a stream into a seq of bytes
11:03	RSchulz	We're not assuming byte streams, are we? Isn't this an abstract stream?
11:03	rhickey	Chouser: not really, I'm done helps, but not all scenarios work that way, ultimately all resource management is - you init, you clean up, even if by explicitly assigning the responsibility to someone else
11:04	rhickey	but context comes into play as well, can't let resources leak, and there is no solution for unbounded usage context for anything other than memory
11:04	rhickey	so, LFE or with-open
11:04	rhickey	my lfe has you getting passed a stream inside, guaranteed to be bad outside
11:05	rhickey	(reduce-lines fn-of-a-stream afile-spec)
11:06	rhickey	stream-lines a better name
11:07	rhickey	file closed when done
11:07	rhickey	this vs line-seq, which must be paired with with-open
11:07	duck1123	I just added Clojure to the Java template on wikipedia. Should drive more people to that page. (and clojure.org in turn)
11:10	rhickey	RSchulz: right stream as in generator as in ephemeral sequence
11:11	RSchulz	Right. I was just clarifying for Zephtar's sake.
11:12	rhickey	it's really just the old file read protocol, seems well worn and understood
11:12	rhickey	I'm still ponderng unread/pushback
11:13	whidden	for what its worth I like thinking of streams as "ephemeral" sequences. It reminds me a little of the Sun OS device streams.
11:13	whidden	In the Sun streams you could push/pop consumers/producers on to the "stream"
11:14	whidden	to allow for arbitrary processing, etc.
11:14	RSchulz	You mean the old SVR3 streams model?
11:14	RSchulz	Is that still around?
11:14	RSchulz	It was pretty cool.
11:14	whidden	yes
11:14	RSchulz	It actually came out of Bell Labs.
11:15	whidden	I think the Sun model added a bit to original Bell Labs stuff, but I could be wrong, or mis-remember :)
11:16	RSchulz	That all was near the end of my Unix kernel days, so I don't know what happened after it got into Sun's kernel.
11:17	whidden	I think what sun added was to allow for consumers/producers of streams to get out the kernel space for most of their processing, akin to what the Mach Microkernel wants/wanted to do.
11:44	mibu	is there a mirror for clojure.org?
11:52	danlarkin	there's always the google cache
11:53	RSchulz	Is there any particular need for mirror?
11:58	duck1123	If I'm using gen-class, does the classloader need any funky permissions to load the implementations?
11:59	duck1123	possibly something that might be turned off in some situations?
11:59	Chousuke	doesn't gen-class just use the regular java classloader? :/
12:00	Chousuke	the classes are AOT compiled so they should be no different from java classes, right?
12:01	duck1123	that's what I was thinking, but I remember reading something about some security situations where AOT gen-class wouldn't work right now.
12:01	duck1123	IIRC, android had that situation
12:01	duck1123	I'm still trying to figure out why my servlet works in Jetty, but not in Tomcat
12:02	duck1123	a guy in #tomcat suggested it may be a classloader issue
12:03	duck1123	all of my classes are on the classpath, so that's not the issue
12:03	stuarthalloway	duck1123: "all classes on classpath" does not imply "not classloader issue" :-)
12:05	stuarthalloway	check the classloader delegation of the class that successfully loads, closest to the point of the problem
12:06	stuarthalloway	one possible problem is that some classes are on more than one classpath
12:06	stuarthalloway	last I checked, Tomcat has 6 classpaths: core, extensions, system, tomcat-core, webapp-shared, and webapp-specific
12:07	stuarthalloway	with the "system" being the one configured by the CLASSPATH variabile
12:08	duck1123	$CLASSPATH is empty, I'm not sure I follow the rest of your suggestion
12:09	duck1123	fair enough. I'll keep hacking at this
12:12	duck1123	it's not a runtime codegen issue. Hibernate uses RTCG, and since Hibernate works with Tomcat, that can't be the issue
12:36	stuarthalloway	duck1123: do you have a stack trace?
13:03	duck1123	stuarthalloway: no, I'm not getting any exceptions
13:04	stuarthalloway	what's the symptom, then?
13:04	duck1123	All I'm getting is a 404 error when I try to load my servlet
13:04	duck1123	It works in Jetty, but not in Tomcat
13:05	stuarthalloway	have you tried placing a Java-created servlet or JSP in the web app to see if that works?
13:05	duck1123	yes. Works fine
13:05	stuarthalloway	and nothing in the logs?
13:05	duck1123	nope
13:06	stuarthalloway	if I simply use Clojure to stub the servlet interface will the be close enough to what you have to be a useful comparison?
13:08	duck1123	my code is at http://paste.lisp.org/display/71768#2
13:15	stuarthalloway	I'll give it a try
13:16	duck1123	I can paste the web.xml file too if you need it, but it's quite simple
13:34	Lau_of_DK	Do we have a Clojure-func for dumping a string to file?
13:34	AWizzArd	in contrib, (spit ...)
13:35	Lau_of_DK	Thanks
13:39	Lau_of_DK	Is there a function to download a page like www.google.com ?
13:39	AWizzArd	yes, in contrib
13:40	AWizzArd	(duck-stream/reader "https://www.google.de/")
13:40	AWizzArd	it can also read files, http and ftp
13:45	stuarthalloway	duck1123: how are you compiling the servlet, and do you get an error?
13:46	stuarthalloway	I tried (compile 'net.mycyclopedia.Servlet), which created some classes but also reported an error: java.lang.ClassNotFoundException: net.mycyclopedia.Servlet$_doGet__78
13:46	duck1123	I wasn't getting any errors
13:47	duck1123	I think you might need to add the tomcat libs to your classpath
13:47	duck1123	servletapi in particular
13:47	Lau_of_DK	AWizzArd: Do I pull the new jar in with (use 'clojure.something) ?
13:48	AWizzArd	when you have the clojure-contrib.jar in your CP then you can immediately use it next time you start up Clojure.
13:48	AWizzArd	use and require are there to allow you to call functions with a shorter name
13:48	AWizzArd	not to make it possible to use them... that's what the cp is for. As soon stuff is in there your app can call all functions from the libs in the .jar
13:50	AWizzArd	instead of typing always (clojure.contrib.duck-streams/reader ...) you can say (require '[clojure.contrib.duck-streams :as ds]) and then (ds/reader ...)
13:50	Kerris7	I wanna buy rhickey_ a copy of the Qi book, let him flip through it, see what he thinks of it
13:51	Lau_of_DK	Good tip, thanks AWizzArd
13:51	kotarak	1:6 user=> (clojure.contrib.duck-streams/reader "http://www.google.de")
13:51	kotarak	java.lang.ClassNotFoundException: clojure.contrib.duck-streams (repl-1:6)
13:51	kotarak	1:7 user=> (require 'clojure.contrib.duck-streams)
13:51	kotarak	nil
13:51	kotarak	1:8 user=> (clojure.contrib.duck-streams/reader "http://www.google.de")
13:51	kotarak	#<BufferedReader java.io.BufferedReader@a8f100>
13:51	kotarak	So it's not totally optional.
13:52	stuarthalloway	duck1123: Tomcat is on the classpath, it's something else
13:52	stuarthalloway	...and different from the problem you have :-)
13:53	duck1123	ahh! (set! compile-path "WEB-INF/classes")
13:54	stuarthalloway	oh, you aren't putting the files there?
13:54	AWizzArd	kotarak: ah okay right, I already forgot that because I added that guy in my (ns ... (:require ...)) anyway
13:55	duck1123	did it create the class files for you?
13:55	stuarthalloway	yes, but perhaps not correctly
13:55	duck1123	I think by default it'll put them in classes/ not WEB-INF/classes
13:56	stuarthalloway	I put them in my working directory and copied them over myself
13:56	duck1123	ok, I had them build right into the correct location
13:57	stuarthalloway	here'
13:57	stuarthalloway	here is what I am seeing: http://paste.lisp.org/display/71866
14:02	stuarthalloway	nevermind, reading the docs saves the day once again
14:08	Lau_of_DK	Didnt we used to have a not-nil? ?
14:09	Lau_of_DK	nevermind
14:31	Lau_of_DK	Isnt (org.apache.commons.io FileUtils) standard when you have apache2 installed?
14:33	hiredman	I imagine it depends on who you get your apache from
14:33	stuarthalloway	Lau_of_DK: what do apache2 the webserver and Apache Commons the Java library have in common?
14:34	Lau_of_DK	stuarthalloway: trick question?
14:34	stuarthalloway	other than a brand name...?
14:34	stuarthalloway	no, seriously
14:34	hiredman	they are part of the apache foundation, whatever that means
14:34	hiredman	projects of the "
14:34	stuarthalloway	all the Java "Apache" packages are former "Jakarta" packages
14:34	Lau_of_DK	I found a simple example in Java to dump a file, where they import (org.apache.commons.io) so I figured it was some kind of bundle since no special notice was made about the import
14:35	stuarthalloway	just google "Apache Commons" --it's a single jar
14:35	hiredman	uh, really?
14:35	stuarthalloway	well, commons is anyway
14:36	stuarthalloway	apache the web server isn't written in Java, so I don't see why it would ship with much in the way of Java libs
14:37	Lau_of_DK	thanks stuarthalloway, right you were
14:42	Lau_of_DK	http://www.kodejava.org/examples/55.html
14:42	Lau_of_DK	Can somebody tell me why they dont close the File. object ?
14:42	hiredman	spite?
14:43	hiredman	java.io.File objects are not opened or closed
14:43	hiredman	they are not an io stream, they are a file
14:43	Lau_of_DK	As I recall, file objects are closed so guarantee the final flush
14:44	hiredman	and the writestring method must take care of opening an io stream
14:44	hiredman	Lau_of_DK: I pretty sure you are thinking of iostreams
14:44	Lau_of_DK	k
14:45	hiredman	http://java.sun.com/j2se/1.4.2/docs/api/java/io/File.html <-- doesn't have a close method
14:45	RSchulz	Doesn't have one. Never will...
14:45	Lau_of_DK	Right you are
14:45	Lau_of_DK	RSchulz: What an incredibly useful comment :)
14:45	hiredman	never say never
14:45	RSchulz	I can't be helpful 100% of the time.
14:46	RSchulz	Except, of course, to utter the timeless phrase: "Never say never."
14:46	Lau_of_DK	hehe
14:47	danlarkin	and the phrase explaining it
14:48	RSchulz	Which one?
14:48	RSchulz	PTV was just one the other day. So hilarious.
14:49	hiredman	is there anything in contrib for csv munging?
14:50	hiredman	or does anyone know of a nice java lib for it?
14:50	danlarkin	lisppaste8: url
14:50	lisppaste8	To use the lisppaste bot, visit http://paste.lisp.org/new/clojure and enter your paste.
14:51	lisppaste8	danlarkin pasted "OT time wasting" at http://paste.lisp.org/display/71869
14:51	danlarkin	RSchulz: that's the quote I'm thinking of
14:58	RSchulz	Yup. I know that episode.
15:00	Lau_of_DK	lol
15:35	Lau_of_DK	Is there a simple way to download an .html file and have the javascript evaluated? It will generate some tables which I need the data from
15:37	danlarkin	Lau_of_DK: simple way? no
15:40	Lau_of_DK	danlarkin: Alright, I just need to have it done by midnight, 2� hours from now, where do I look ?
15:41	danlarkin	well you'll need to evaluate the javascript
15:41	danlarkin	so you can either embed a javascript engine or try to shell it out to somewhere
15:59	RSchulz	Does anybody know of work similar to http://okmij.org/ftp/Streams.html that isn't phrased in terms of Haskell? I don't know the language and find it entirely abstruse.
16:06	hiredman	I am trying to write a macro the defns some functions,
16:06	hiredman	java.lang.Exception: Second argument to def must be a Symbol (NO_SOURCE_FILE:591)
16:07	hiredman	it seems like the first argument to def is supposed to be a symbol?
16:08	mfredrickson	RSchulz: which part specifically -- not that I have anything for you, I'm just curious
16:09	mfredrickson	(i've been thinking about linear algebra in Clojure for the last few days, so that caught my eye)
16:09	RSchulz	Well, as a language heavy in syntactic sugar, I find I can't get past line one of any example.
16:09	RSchulz	However, I just found a "cheat-sheet" (13-page tutorial) on Haskell, which should prove helpful.
16:10	duck1123	that's a hell of a cheat sheet
16:10	RSchulz	Exactly what someone remarked on the comment page where I found it...
16:11	RSchulz	I see that it is written "quick reference card" format (three-column landscape)
16:11	RSchulz	For those interested: http://blog.codeslower.com/2008/10/The-Haskell-Cheatsheet
16:31	AWizzArd	Is there a java lib for obfuscating a database?
16:31	AWizzArd	(as in oracle, postgres, mysql, ...)
16:31	RSchulz	What sort of obfuscation?
16:36	AWizzArd	database obfuscation that will semantically leave all data inside the db, but rename tables, fields, contents, etc.
16:36	AWizzArd	So that someone who is not dedicated into finding out the scheme behind this won't be able to read the db
16:37	danlarkin	AWizzArd: you are asking for a maintenance _nightmare_ by doing that
16:37	AWizzArd	Can you tell me more about this?
16:38	RSchulz	I can't see the virtue. Unlike Java code, you don't have to (and should not want to) expose your DBMS to arbitrary client use.
16:41	Chousuke	database obfuscation sounds like something you should never need :/
16:41	Chousuke	but I can't say for sure, people have had need for many weirder things :P
16:59	jawolfe	hi, i'm new to clojure and have a performance question, if anyone can help ...
17:00	danlarkin	don't ask to ask, just ask :)
17:00	jawolfe	(defn mypow [x n]
17:00	jawolfe	(let [x (double x)]
17:00	jawolfe	(loop [ret (double 1.0) n (int n)]
17:00	jawolfe	(if (= n 0) ret (recur (* ret x) (unchecked-dec n))))))
17:00	RSchulz	Woo-Hoo! "[Pragmatic Bookstore] An updated version of Programming Clojure (PDF) is available"
17:01	RSchulz	Changes in this version include:
17:01	RSchulz	Chapter 7, Macros
17:01	jawolfe	is my best attempt at an efficient clone of the pow function for ints
17:01	jawolfe	int exponents i mean
17:01	jawolfe	but its still 10 times slower than the same code in SBCL
17:01	whidden	RSchulz: gee you're behind the times... already 1/2 trough that chapter :)
17:01	RSchulz	I'm probably just further down the email distribution list...
17:01	jawolfe	Is there something I'm doing wrong?
17:01	RSchulz	Now I have to wait for the gerbils.
17:02	jawolfe	(of course, I'm not writing for its own sake, just to get an idea how much performance hit I may take switching to Clojure from SBCL)
17:03	whidden	jawolfe: there looks to be an unchecked "times" in the recur.
17:04	Chouser	(doc unchecked-multiply)
17:04	clojurebot	Returns the product of x and y, both int or long. Note - uses a primitive operator subject to overflow.; arglists ([x y])
17:05	jawolfe	right, thanks. but x is a double ... is there a corresponding version of unchecked-multiply for doubles?
17:05	Chouser	oh. :-P doesn't appear to be.
17:06	Chouser	jawolfe: you're running mypow multiple times (hundreds or thousands) with -server on your java command line?
17:06	RSchulz	jawolfe: I'm not an expert on numerics, but for a floating-point value, isn't all the same? You'll get an infinity if you overflow, not an exception, right?
17:07	jawolfe	Chouser: I'm running it 3 times, with very large arguments
17:07	jawolfe	Chouser: (dotimes [i 3] (time (print (mypow 1.00000001 100000000))))
17:08	jawolfe	RSchulz: I don't really care about overflow, I'm wondering about speed. I can't get the clojure version to run better than 10 times slower than the corresponding SBCL version.
17:08	RSchulz	My point is that there's not difference. The checking doesn't happen in machine code, it happens in the FPU.
17:09	jawolfe	Chouser: yes, with -server
17:09	RSchulz	(If I understand correctly, which I'm not really sure I do.)
17:09	jawolfe	OK, that sounds right to me ... I'm not sure where the slow-ness is coming from
17:09	Chouser	try (zero? n) instead of (= n 0)
17:09	jawolfe	Just that adding type declarations only sped things up less than 25%, when I was hoping for more like 20x.
17:10	RSchulz	For kicks, did you try it with float instead of double?
17:10	RSchulz	What hardware are you running on?
17:10	jawolfe	Chouser: you win.
17:10	jawolfe	that cuts down by a factor of 10
17:11	RSchulz	Wow.
17:11	Chouser	the problem there was both = and 0
17:11	RSchulz	The 0 is a BigInt?
17:12	jawolfe	0 is an Integer I guess?
17:12	Chouser	I think = always uses Object, so it boxes its args. You could use == instead.
17:12	RSchulz	Acquired using valueOf(0)?
17:12	Chouser	Right 0 is also a boxed integer, so (== n 0) isn't any faster.
17:12	RSchulz	This is one of the things that Cliff guy was talking about in his presentation at the JVM summit.
17:12	Chouser	But (== n (int 0)) lets everything stay primitive
17:12	jawolfe	(= (int 0) n) is slow too
17:13	jawolfe	Yeah, you're right ... (== (int 0) n) does it.
17:13	jawolfe	Thanks for your help, I probably would never have figured that out.
17:14	Chouser	and of course 'zero?' is prettier
17:14	drewr	More Schemey anyway.
17:15	jawolfe	I didn't know about == either, I don't recall seeing it in any of the docs I've read
17:16	Chouser	But when trying to decide if Clojure is a good risk, don't forget that for tight loops like this that really matter in your real app, you can always drop to Java or even use JNI and native code if you can't find any other way.
17:17	Chouser	In practice I think it's unlikely you'll ever need to.
17:17	jawolfe	Yeah, I realize that ... but I tend to do a fair amount of probabilistic stuff and so having at least the possibility of efficient math without dropping into Java (shudder) makes me much happier.
17:18	hiredman	lisppaste8: url?
17:18	lisppaste8	To use the lisppaste bot, visit http://paste.lisp.org/new/clojure and enter your paste.
17:18	jawolfe	One more quick question: my SLIME interrupts don't seem to work with Clojure, does anyone know what gives?
17:18	Chouser	hopefully the JVM will get tagged numbers eventually and make staying on the fast path less tricky.
17:19	lisppaste8	hiredman pasted "getters macro" at http://paste.lisp.org/display/71878
17:19	jawolfe	yes that would definitely be nice
17:19	hiredman	anyone up for some macro help?
17:20	RSchulz	What help do you have?
17:20	jawolfe	haha
17:20	hiredman	you are truly hilarious sir
17:20	Chouser	jawolfe: sorry, I don't use SLIME. But plenty of others do, surely they'll speak up any moment now...
17:21	jawolfe	Chouser: no worries, thanks ... what do you use?
17:21	hiredman	somehow I seem to be not evaluating something in my macro instead of accidently evaluating twice
17:21	Chouser	vim and a repl in a terminal.
17:21	RSchulz	I'll see if I can read ahead fast enough in chapter 7 of Stu's book to give you an answer.
17:22	drewr	jawolfe: I use SLIME, but don't much experience with CL. What do you mean by interrupts? You mean restarts?
17:22	RSchulz	Is it the 71878
17:22	RSchulz	?
17:22	hiredman	RSchulz: yess
17:22	Chouser	clojurebot: macro help?
17:22	clojurebot	macro help is http://clojure-log.n01se.net/macro.html
17:22	Chouser	hiredman: ^^^
17:23	jawolfe	drewr: I mean, how do you interrupt what's running at the REPL
17:23	RSchulz	Doesn't a def have to appear at the top level? You've got it in a let body.
17:23	jawolfe	drewr: like, if you type (repeat 0)
17:24	hiredman	Chouser: the macro works fine if I just use it, but I try to use it in a map and I get something not right
17:24	RSchulz	defn is itself a macro...
17:24	drewr	jawolfe: I think someone was working on that, but I'm not sure the JVM is going to play nicely.
17:25	Chouser	jawolfe: setting print-length helps
17:25	hiredman	RSchulz: the macro forks fine if I call it directly (not using map)
17:25	hiredman	er
17:25	hiredman	works
17:25	RSchulz	I think it has something to do with when the macro is applied. It's happening once, not once per iteration of the map.
17:26	lisppaste8	hiredman annotated #71878 with "no map" at http://paste.lisp.org/display/71878#1
17:26	RSchulz	So you get the same result repeatedly.
17:26	jawolfe	Chouser: thanks
17:26	drewr	When it's unresponsive, I kill the java process and restart. :-/ You can write a function to do it automatically.
17:26	jawolfe	drewr: hmmm, so you have to killall lisp and start over?
17:26	hiredman	RSchulz: there is no :x key to that map
17:26	jawolfe	er i mean killall java
17:27	hiredman	the X must be the x paramter to the (fn [x] ...) in the map
17:27	RSchulz	It's suspiciously similar to (up-first-letter "x")...
17:27	hiredman	that is the only place x is anywhere in the code
17:27	drewr	jawolfe: Yeah, but I tend to keep my code in buffers where I can do a quick C-c C-k and keep going.
17:27	RSchulz	Change it to y and see if the result under map changes similarly...
17:28	jawolfe	drewr: makes sense, just a bit annoying ... interrupting can be especially nice for debugging
17:28	hiredman	RSchulz: uh, there is no (up-first-letter "x")
17:29	RSchulz	You know what I mean.
17:29	Chouser	try: `(name ~k)
17:29	jawolfe	drewr: but i'll take what i can get
17:29	hiredman	no I don't
17:29	RSchulz	Just try it. change that x to something else and see what happens under map.
17:29	drewr	jawolfe: Definitely. That's really my only complaint with Clojure compared with CL. Debugging feels more cumbersome. But you learn tricks that at least make it scientific. :-)
17:29	hiredman	Chouser: Unable to resolve symbol: k in this context
17:30	Chouser	oh. uh.
17:30	RSchulz	You don't think the X in the result, the up-first-letter and the x in your macro definition are suspicious?
17:30	RSchulz	Suggestive of some relation between them?
17:30	Chouser	`(name ~ky)
17:30	Chouser	RSchulz: I think you've got your finger on it.
17:30	jawolfe	drewr: Good to know, thanks!
17:31	lisppaste8	hiredman annotated #71878 with "x to y" at http://paste.lisp.org/display/71878#2
17:31	jawolfe	OK, thanks for your help all. Time to try to write my first real clojure code ...
17:31	hiredman	oh
17:31	hiredman	woa
17:31	hiredman	bug
17:32	drewr	jawolfe: No problem. Don't be afraid to ask for help. We all usually learn something.
17:32	hiredman	still doesn't work, but what I pasted as k where ky should be in the macro
17:36	Chouser	ky is the object passed in. ':id' in one case, 'x' or 'y' in the others.
17:37	Chouser	all of that has nothing to do with a value that may or may not be stored in a local or global var by that name.
17:37	gnuvince_	I thought ky was what was used to pass objects in ;-)
17:37	hiredman	?
17:37	gnuvince_	</bad joke>
17:37	Chouser	ouhc
17:37	Chouser	ouch
17:37	Chouser	or not, I suppose.
17:38	hiredman	the only place in my code the getter macro could be getting the
17:39	hiredman	x or y is from the fn surrounding the call to getter
17:39	Chouser	hiredman: think about it this way. The whole 'map' expression gets compiled once, so you macro gets run once.
17:40	hiredman	Chouser: if the macro gets compiled once, how come I get a whole list of the result of (defn) stuff?
17:41	Chouser	the expression your macro returns gets evaluated for each item in the seq
17:41	RSchulz	The code it produces gets mapped across the sequence supplied.
17:41	hiredman	ok
17:41	hiredman	I guess
17:41	hiredman	thanks
17:42	Chouser	to see what that expression is, use: (macroexpand '(getter f "family" x))
17:42	RSchulz	But keep in mind that macroexpand only expands until the top level of an expansion is no longer a macro application.
17:43	RSchulz	If there are nested macros, they won't be expanded by macroexpand.
17:43	Chouser	right, which is why you want to run it directly on the macro you wrote
17:43	RSchulz	Someone posted a pevasive macro-expander.
17:43	AWizzArd	you need to manually expand all macros if you want to write a code analyzer tool
17:44	RSchulz	I'd rather wait for someone else to write a code analyzer tool.
17:44	AWizzArd	RSchulz: eval must be doing it
17:44	RSchulz	I have code to write...
19:24	clojurebot	svn rev 1149; added :exposes-methods to gen-class, patch from Matt Revelle
20:25	pjb3	Has anyone tried building an Android app with Clojure yet?
20:26	Chouser	As far as I know, if Android worked applets would as well.
20:27	Chouser	The last time I tried an applet it did not work, as a dynamic classloader is still created.
20:28	RSchulz	Do the Android tools operate at the JVM bytecode level, or at the Java source-code level?
20:28	RSchulz	Wait, I guess it must be bytecode, 'cause I heard of people getting Scala code working on Android.
20:29	RSchulz	So with AOT it should work, in principle, right?
20:38	Chousuke	RSchulz: bytecode AFAIK.
20:40	Chouser	RSchulz: yes, I think once the dynamic classloader is fully optional, applets and android ought to work
20:40	Chousuke	Google's being pretty clever. apparently they have their own bytecode to get around some restriction imposed by sun; so they're not officially Java-compatible, just de facto so :P
20:41	Chouser	or be able to be made to work.
20:41	RSchulz	I don't think I see the significance of dyamic classloaders.
20:41	Chouser	for android?
20:41	RSchulz	Actually, don't they _translate_ JVM to an entirely separate set of opcodes?
20:41	RSchulz	In general. What's the issue with dynamic classloading that's tripping up Clojure-generated bytecodes?
20:42	Chousuke	RSchulz: as far as I know, yes
20:42	mattrepl	it's register-based
20:42	Chouser	in non-AOT code, each Clojure expression is compiled into Java bytecode and then has to be loaded to run
20:43	RSchulz	Right.
20:43	Chouser	that's a problem for applets because they don't trust your custom dynamic classloader
20:43	RSchulz	Ah.
20:44	Chouser	it's a problem for android because the runtime platform has no ability to translate Java bytecode to what it needs to run -- that's a development and compile-time function.
20:44	RSchulz	How do the other dynamic languages, Groovy, Scala, handle this problem? I run my Grails app under Tomcat without problem.
20:44	Chouser	As far as I know, tomcat runs Clojure code fine.
20:44	RSchulz	But that's where AOT comes in, right? You get all the bytecodes up front for Android's tools to translate.
20:45	RSchulz	I think duck1123 would disagree with you...
20:45	Chousuke	that would disallow redefining stuff at runtime though. :/
20:45	Chouser	yes, AOT when fully realized should solve both the applet and android problems, and it's getting very close, but it's not quite there yet.
20:46	RSchulz	Right... So only those programs that, in essence, require the Clojure compiler at run-time (after AOT compilation) would be left out.
20:47	Chouser	I saw webjure hello world work in tomcat months ago. I'm not sure what's causing problems for duck1123, but I don't think it's anything inherent in Clojure.
20:47	Chouser	RSchulz: right. like a REPL, for example.
20:47	RSchulz	I foresee the day that Android's device-resident run-time includes a JVM bytecode -> Android opcode translator.
20:47	RSchulz	Well, if I can't run a Clojure REPL on an Android phone, it's no-sale for me.
20:48	Chouser	you could write a clojure interpreter (in Clojure, if you wanted) and then you'd be all set.
20:48	RSchulz	Of course, I've yet to buy my first cell phone.
20:48	RSchulz	... Yeah. I'm a real retro-grouch.
20:49	RSchulz	I wonder... Does anybody know of Android in a non-cell-phone device?
20:49	RSchulz	I guess that would be a PDA, basically.
20:49	RSchulz	I don't suppose there's much of a market for such a thing.
20:55	duck1123	Chouser: Webjure uses actual java, not pure clojure
21:16	jawolfe	Hi again. I'm wondering how to re-export vars from a namespace. Suppose I have namespaces a, b, and c, and i'd like to export some subset of all of their functions under a single new namespace d. Is this possible, and/or is there a more ideomatic way to produce "interfaces" to large collections of code? Thanks...
21:19	hiredman	jawolfe: http://clojure.org/api#toc358 should get you started
21:19	duck1123	so you want to be able to require d and have select fns from a b and c available?
21:21	jawolfe	duck1123: yes, exactly
21:22	jawolfe	hiredman: thanks, have already read the docs. all i was able to find were cryptic references to "public vars" without any details of what they are or how to make a var "public"
21:23	duck1123	jawolfe: in that case, I don't know of anything to really do that
21:24	jawolfe	duck1123: thanks
21:24	duck1123	but you could probablt have a macro to take a seq of symbols to require
21:24	duck1123	def the macro and the var in d, then call it from e
21:25	duck1123	you might not even need the macro
21:25	jawolfe	hmmm, that could work
21:26	jawolfe	although i'd rather not have to do anything extra in e
21:27	jawolfe	i'm not necessarily tied to this type of organization
21:27	jawolfe	but just trying to start a big project
21:27	jawolfe	and wondering how best to organize and compartmentalize things
21:30	RSchulz	I'm not sure it's documented or if I just saw it in reading Clojure code, but (def- ...) and (defn- ...) define "private" (non-exported) Vars.
21:33	RSchulz	Actually, the only private def form in core is (defn- ...)
21:34	RSchulz	Others, defmacro-, defonce-, defstruct-, defunbound- and defvar- are defined in clojure.contrib.def
21:35	jawolfe	Thanks, that helps
21:38	jawolfe	It still seems useful to me to have a way to declare refer'd symbols as public in a namespace
21:39	jawolfe	i guess i can simulate by defining new vars in the namespace with values copied from other namespaces ...
21:39	jawolfe	ah well, gotta go, thanks for your help.
23:01	danlarkin	anyone have a remove-whitespace function that won't remove whitespace from inside quoted strings?
23:06	zakwilson	danlarkin: I'm not sure I understand what you mean.
23:07	danlarkin	zakwilson: for unit testing my JSON parser I'm slurping in text files of JSON and encoding them to json and then decoding again and checking against the original
23:07	danlarkin	but part of the test is if it handles wacky unconventional whitespace in the original JSON file
23:08	danlarkin	so when I do (= original-json decoded-json) the original-json has wacky whitespace while the decoded-json doesn't, so they aren't equal
23:09	zakwilson	Ahh... I think I understand. I don't have a function like that, but I do have something for parsing CSV that you could probably adapt without much effort. Want it?
23:09	danlarkin	yes if you would be so kind, that would probably help
23:11	zakwilson	One moment - haven't used a pastebin before, and I need to copy a utility function or two out of another file.
23:17	lisppaste8	zakwilson pasted "function for danlarkin" at http://paste.lisp.org/display/71897
23:19	danlarkin	zakwilson: thanks! :) One thing I notice is that this function can overflow the stack if it recurses too deeply
23:21	zakwilson	danlarkin: How? I was under the impression that recur couldn't overflow the stack.
23:22	danlarkin	scan-for-delimeter calls itself
23:24	hiredman	clojurebot: mk-bean is http://gist.github.com/34229
23:24	clojurebot	Roger.
23:24	zakwilson	So it does. I thought I had changed it to recur, and I think it could be so changed.
23:25	zakwilson	I was using the self-calls to make a stack overflow possible after an early attempt resulted in an infinite loop.
23:25	Chouser	(apply str (re-seq #"\"(?:[^\\]\|\\.)*?\"\|\S" text))
23:25	Chouser	that's probably buggy. :-)
23:26	Chouser	you don't need to handle chunks quoted with 'single quotes' do you?
23:27	Chouser	gotta scoot. later, all.
23:28	zakwilson	Just changed it to recur and it works.
23:28	danlarkin	ah yes zakwilson, I'm all too familiar with infinite looping :)
23:30	zakwilson	I've gotten in to the habit of using self-calls instead of recur when I'm not sure about the end-test in a function.
23:59	danlarkin	Chouser-away: I think that regex works, thanks