#clojure – 2011-07-17

2011-07-17

00:25	Blackfoot	can i update a hierarchy used in defmulti after the defmulti call?
00:28	Blackfoot	oh i see :hierarchy can be a ref. nm
00:45	amalloy	Blackfoot: see ##(doc derive). if you want to remove links in the hierarchy tree, that's probably not a good idea
00:45	lazybot	⇒ "([tag parent] [h tag parent]); Establishes a parent/child relationship between parent and tag. Parent must be a namespace-qualified symbol or keyword and child can be either a namespace-qualified symbol or keyword or a class. h must be a hierarchy obtained from mak... http://gist.github.com/1087197
00:49	Blackfoot	amalloy: no, wanted to add them. my confusion stemmed from the fact isa? doesn't work recursively through lists
00:49	Blackfoot	but it does through vectors, so i'm all good
00:49	amalloy	yeah, i was surprised to learn that vectors have that feature. it's handy
05:25	Pupeno	I followed the instruction on getting started with Emacs with Clojure. I installed Emacs 23.3.1 and the packages. When I run clojure-jack-in it says Starting swank server... and gets stuck there. Any ideas how to find out what's going on? what's the problem? some logs?
05:27	bsteuber	Pupeno: if you don't see error-messages in slime-events or messages, I'd assume you missed to install the slime-repl elpa package
05:28	Pupeno	bsteuber: no buffer was open at all... I just did M-x package-install and choose clojure-mode
05:29	Pupeno	OK... there were some buffers but not shown.
05:29	Pupeno	Process swank exited abnormally with code 1
05:29	Pupeno	That's not a task. Use "lein help" to list all tasks.
05:32	Pupeno	lein repl works on the console.
05:32	amalloy	Pupeno: lein --version
05:33	Pupeno	Leiningen 1.6.0 on Java 1.6.0_26 Java HotSpot(TM) 64-Bit Server VM
05:33	amalloy	i suspect you have a version from before technomancy added jack-in to clojure-mode
05:33	amalloy	hm
05:33	amalloy	well, i don't use lein, but i'm pretty sure that version has support
05:34	Vinzent	Pupeno, do you have swank in your :dev-deps?
05:34	Pupeno	Vinzent: I don't know what that means, so probably not.
05:35	Vinzent	Pupeno, add [swank-clojure "1.3.1"] to your :dev-dependencies in project.clj
05:39	Pupeno	Where should that project.clj file be?
05:41	Vinzent	Pupeno, in the root of the project dir. lein new will create it for you.
05:41	Pupeno	I don't have a project yet, I just wanted to play around... do I have to create a project for slime to work with cljure?
05:42	Vinzent	Yes.
05:43	Vinzent	lein new, then edit project.clj and add necessary dependencies, then lein deps, then jack-in from emacs
05:44	Pupeno	Vinzent: how do I tell emacs where the project is?
05:45	Vinzent	Pupeno, just open some file from that project, and run jack-in from that file
05:46	Vinzent	(or you can run lein swank manually, then slime-connect from emacs)
05:47	Pupeno	I got this error now in the swank buffer: https://gist.github.com/1087404
05:50	Vinzent	I think it's something wrong with your project.clj. Take a look at sample.project.clj in the leiningen repo on github.
05:51	Pupeno	Vinzent: it was created by lein: https://gist.github.com/1087410
05:52	Vinzent	Pupeno, but where the :dev-deps part? http://paste.lisp.org/display/123312 here is a sample
05:53	Pupeno	Vinzent: sorry, that was the generated one.
05:54	Pupeno	And I did it wrong.... let's try again.
05:56	Pupeno	Same thing.
05:56	Pupeno	Process swank exited abnormally with code 1
05:56	Pupeno	That's not a task. Use "lein help" to list all tasks.
05:57	Pupeno	Hold on.
05:57	Vinzent	have you ran lein deps?
05:59	Pupeno	Nope
06:01	Pupeno	Seems to be working now... :)
06:01	Pupeno	At least swank is getting thousands of expressions.
06:01	Pupeno	SLIME!
06:01	Pupeno	Thanks Vinzent!
06:04	Vinzent	no problem :)
06:09	tufflax	This http://pastebin.com/D0kXBcYv takes forever to run. Running (map sk (range 1e6)) takes several minutes. What can I do to speed it up?
06:12	Pupeno	Now I can get started preparing the conference showing how awesome Lisp is.
06:12	tufflax	...with a doall around the map call of course :p
06:18	Vinzent	tufflax, btw, in emacs the major part of time usually takes printing results to the buffer. Use (time ...) to know actual running time and print-length to avoid printing the whole sequence
06:21	Vinzent	about the code itself, sorry I can't advice you anything new: try to use primitive types, maybe unchecked arithmetic operations
06:28	tufflax	ok, i'll try. thanks
06:28	Pupeno	Yay, now it also works in Aquamacs.
06:38	minou	Im new to clojure and lisp, i want to make a square 2 dimension vector which is gonna be a maze, i want to fill it in a loop with ones or zeroes, can anyone help me to do this? i have trouibles with modifying vector since its not easy to do mutations to state
06:40	Vinzent	minou, vectors are immutable; if you are really need state, you should read about atoms and refs.
06:41	Vinzent	First, write a function that returns new vector filed with ones or zeroes
06:41	minou	i have one which returns a new vector filled with nils
06:41	minou	a new matrix
06:42	minou	its a matrix i mean 2-dimension vector
06:42	minou	then i try to fill it through recursion and mantaining the matrix as accumulator variable, but i stuck because i cant do the recursion dont know why
06:43	minou	it says Can only recur from tail position
06:43	minou	but i think i do it only in tail positions
06:44	minou	is it possible to do it with a while loop or a loop rebinding each time the matrix?
06:45	Vinzent	Compiler doesn't lie; you have call to recur in the non-tail position if it tells you so :) Maybe you understand tail position wrong?
06:45	Vinzent	Maybe it's possible, but it will be a bad piece of code
06:46	minou	yeah, surely i dont understand what it means....
06:47	minou	but its a common piece of code, where can i see something similar?
06:47	minou	i will google it
06:48	Vinzent	Sorry, I can't give you good links about it, but I have definitely seen some blog posts about it
07:34	tufflax	minou http://pastebin.com/UniJ1k6q
07:34	tufflax	oh, he left
07:44	bsteuber	weird, I'm using Thread/setDefaultUncaughtExceptionHandler but when I do (Thread. #(/ 1 0)) it won't get called
08:02	Pupeno	In Slime RELP, how do I get the previous line?
08:02	bsteuber	Pupeno: M-p
08:05	Pupeno	Is there a name to call things that could me macros or functions? For example, "In a Lisp form, the first item is the .... and the rest are the arguments". What would ... be?
08:07	bsteuber	maybe verb
08:07	Vinzent	or command?
08:08	bsteuber	command sound so imperative to me ^^
08:09	frou100	You know the socket repl that "lein repl" starts, is there a way for the client on the other end of the socket to get exception messages? Presumably they are stderr and not being sent.
08:09	tufflax	Pupeno operator maybe
08:10	Vinzent	well, then "function" imo would be just fine (to not to overload listener with the details)
08:12	bsteuber	Pupeno: for what do you need it anyways?
08:51	Pupeno	bsteuber: to use the proper term when speaking.
09:05	Pupeno	ns is the proper way to create namespaces, and in-ns to switch to them when necessary, is that correct?
09:35	bsteuber	forfeit liest sich schöner ^^
09:36	bsteuber	sorry, wrong tab :)
10:01	raek	Pupeno: yes
10:01	Pupeno	Does this short macro make sense: https://gist.github.com/1087614
10:02	Pupeno	It feels good to code in Clojure again :)
10:02	raek	(ns refers all vars in clojure.core unless you say otherwise, so if you want to exclude something in clojure.core, using ns instead of in-ns won't work)
10:03	Pupeno	raek: ok. thanks. :)
10:04	raek	Pupeno: the prints will happen at the times described in their texts, so yes
10:05	Pupeno	raek: thanks :)
10:15	Pupeno	So, ` is the same as ' except that it lets you escape things with ~, right?
10:15	gfrlog	Pupeno: it also namespace-qualifies things
10:15	gfrlog	,['first `first]
10:15	clojurebot	[first clojure.core/first]
10:15	Pupeno	Yeah, I seen that... thanks.
10:15	Pupeno	Is the comma for clojurebot ?
10:16	gfrlog	Pupeno: yes
10:16	Pupeno	ok.
10:16	mudge	what does it mean for a var to be defined with ^{dynamic true} ?
10:16	gfrlog	&['first `first]
10:16	lazybot	⇒ [first clojure.core/first]
10:16	gfrlog	mudge: in clojure 1.3 that metadata is required to use the var with (binding ...)
10:16	gfrlog	pre-1.3 all vars are dynamic
10:17	mudge	gfrlog: thanks, I search google a lot for an explanation of this and I didn't fine it, do you have a source on the web?
10:17	gfrlog	hmm
10:19	gfrlog	a few brief mentions when I google for "clojure 1.3 ^:dynamic vars"
10:19	gfrlog	I don't think I've looked for it. I first heard about it when Rich talked about it at the conference last year.
10:21	mudge	gfrlog: ah thanks
10:22	mudge	gfrlog: thanks, which event? do you know if there is a video of the talk?
10:24	gfrlog	mudge: the first Clojure Conj. Rich gave two talks, and it should be the one that was not about hammocks.
10:24	mudge	gfrlog: ah, thanks
10:24	gfrlog	mudge: I've not seen it online, but it certainly should be. I'm googling now.
10:27	mudge	gfrlog: yea, I'm looking for it too
10:27	gfrlog	I've had no more luck this time then on previous tries. It's a shame too, because I've wanted to relisten to the part about vars. He explains why the change is a performance benefit, and I've forgotten the details of that.
11:03	mudge	jf
11:09	gfrlog	clojureql doesn't provide a way to lazily consume a large result-set without holding it in memory, does it?
11:13	gfrlog	for that matter maybe clojure.contrib.sql/with-query-results doesn't provide that either :/
11:27	Vinzent	I thought it's just a reference to the sequence, isn't it?
11:28	gfrlog	yeah. I think I've moved on past that and now the most logical explanation seems to be that my DB is spitting data back faster than clojure can reduce it. But that too seems implausible. :/
11:29	gfrlog	I do a SELECT * from a 12,000,000 record table and expect to be able to reduce the results without memory filling up
11:31	Vinzent	hm, maybe query result itself isnt't lazy at all?
11:31	gfrlog	as best I can tell both libraries do it lazily
11:31	gfrlog	c.c.sql defers to clojure.core/resultset-seq, which is certainly lazy
11:34	amac	o/
11:35	Vinzent	but maybe data from db are coming in one big chunk, and then it is just wrapped in a lazyseq? (I really don't know, just thoughts)
11:35	gfrlog	sure, that's theoretically possible. But I would think all the java.sql stuff would be lazy by default...
11:36	gfrlog	unless for some odd reason there's db-server-side config that needs to take place
11:42	gfrlog	okay, now I've confirmed that my code isn't even running -- the driver must be eating up the result and not returning.
11:45	gfrlog	the internets say the only way to make the mysql-jdbc driver lazy is with special arguments to Connection#createStatement. So looks like I'm dipping into java :/
11:49	Vinzent	hm, isn't it a candidate for clojureql issues list, what do you think? It'd perfect clojure libs\wrappers made things as lazily as it possible, especially with stuff like databases
11:49	gfrlog	Vinzent: I think clojureql uses c.c.sql, and the issue is at the c.c.sql level
11:50	gfrlog	this line would need some extra arguments: https://github.com/clojure/clojure-contrib/blob/6a0483d9e216ca00fc648a4b3673996b76a2785a/src/main/clojure/clojure/contrib/sql/internal.clj#L190
11:50	Vinzent	ah, ok
12:53	lnostdal-laptop	i really don't understand why 1.3 has gone about this split thing with regards to clojure-contrib in the way it did
12:54	gfrlog	lnostdal-laptop: I don't think that exactly coincides with 1.3...
12:55	lnostdal-laptop	oh
13:08	mudge	does anyone have any idea when clojure.contrib 1.3 stable release will be out?
13:08	dnolen_	mudge: there will be no such thing.
13:09	mudge	dnolen: I understand that clojure.contrib will be broken up into multiple libraries
13:09	mudge	dnolen: but I don't when to start using them
13:09	gfrlog	right away?
13:10	mudge	gfrlog: they are stable now?
13:10	lnostdal-laptop	they are not stable, and not even remotely complete
13:10	lnostdal-laptop	afaict
13:10	Vinzent	some of them are ready to use with clojure 1.2
13:11	mudge	should i look at each individual library to determine its status?
13:11	Vinzent	yeah, i think so
13:11	gfrlog	some of the libraries seem to have not been copied at all
13:11	gfrlog	I think combinatorics was that way last time I checked
13:15	lnostdal-laptop	it's quite messy .. "they" should have let the Big Blob be as is; or make it both 1.2 and 1.3 compatible really .. then split it only when 1.3 was out and ready i think ... shrug
13:16	lnostdal-laptop	related issue; what replaces print-doc now?
13:17	mudge	the good thing about clojure.contrib is it brings everything together nicely -- so you easily know where to look for functionality outside clojure.core
13:17	mudge	or outside clojure.jar
13:17	lnostdal-laptop	i guess one could have that even when things are split up; a sort of meta-package
13:18	mudge	lnostdal-laptop: yea sounds good, so one could have the big jar with everything, or be able to break it up if one wanted to
13:18	lnostdal-laptop	yup
13:23	mudge	hey, does anyone understand how the unifycle works? http://fogus.me/fun/unifycle/
13:23	dnolen_	mudge: yes
13:24	dnolen_	mudge: but unifycle is now https://github.com/clojure/core.unify, or you can use https://github.com/clojure/core.logic
13:25	mudge	dnolen_: thanks, i don't understand the example, so trying to figure it out
13:26	gfrlog	mudge: do you know how unification works?
13:26	dnolen_	mudge: core.unify is stand alone unification library, core.logic is more efficient and brings a logic engine.
13:26	mudge	gfrlog: not really
13:27	tomoj	does it work with arbitrary lists? doesn't need to be infix?
13:27	dnolen_	mudge: unification takes two terms and attempts to make them equal.
13:27	tomoj	right, so it doesn't care what's an operator or what's data?
13:28	mudge	how can something make terms equal? they are equal or they are not
13:28	gfrlog	mudge: the terms can have variables
13:29	dnolen_	tomoj: unification will work w/ whatever data structures the implementation supports.
13:29	gfrlog	I expect he was asking about unifycle specifically
13:29	gfrlog	mudge: the symbols starting with ? in the example are variables
13:30	mudge	gfrlog: yes
13:30	gfrlog	comparing the values in the two structures may imply a value for a particular variable, e.g. in the example ?x has to be 5
13:30	dnolen_	mudge: (unify '(?x 1) '(2 ?y)), unification will succeed with ?x bound to 2 and ?y bound to 1. (unify '(?x 1) '(2 2)) will fail.
13:31	mudge	dnolen_: yes, i see
13:31	gfrlog	(unify '(?x ?x) (3 4)) will also fail
13:31	mudge	by failing, does that mean it couldn't unify them?
13:31	gfrlog	correct
13:32	gfrlog	notice in the example that not all variables have to be bound in the result
13:33	mudge	gfrlog: yes, and are variables bound to functions too? or not? in (?x ) is ?x bound to ?
13:34	gfrlog	I don't think there's a concept of function. It's just working with literals -- lists, symbols, numbers, etc
13:34	mudge	gfrlog, okay then (?x ) means that ?x is bound to the symbol
13:35	gfrlog	mudge: no, it's a two-element list, with a variable and a symbol
13:36	mudge	gfrlog: so are variables only bound to numbers then? (?x *) is different then (?x 5) ?
13:36	gfrlog	(?x ) and (?x 5) cannot be unified, because is different from 5
13:36	gfrlog	a variable could be bound to a list as well
13:36	mudge	gfrlog: thanks
13:37	gfrlog	(?a ?b ?c) could unify with ((1 2) 3 ?z)
13:37	mudge	gfrlog: i see, thanks
13:37	gfrlog	yep
13:38	mudge	gfrlog: would this unify: (?a ?b ?c) and (* + /)
13:38	gfrlog	yes. The result would be (* + /)
13:38	mudge	gfrlog: cool, thanks
13:39	gfrlog	I should qualify this by saying I've never tried unifycle, I'm just going off of what I think I know about unification
13:39	mudge	gfrlog: so then the unifer just reduces two equal lists into the simplest form?
13:39	mudge	gfrlog: okay
13:40	gfrlog	mudge: well, the main thing it does is look at the varibles and see if there is any way the two lists can be shown to be equal by binding the variables one way or another
13:40	gfrlog	I suppose we're using the word "equal" in a kind of loose sense
13:40	mudge	gfrlog: yes, thanks
13:40	gfrlog	maybe a better way to say it is that unification tries to find the least-specific structure that matches both of the inputs
13:41	gfrlog	where specificity refers to how much of the structure is a variable
13:41	mudge	gfrlog: yes, thanks
13:42	gfrlog	so when unifying (?a 2 ?x) and (3 ?b ?y), you get something like (3 2 ?x), where the last one is left as a variable because it can be
13:43	mudge	gfrlog: yes, with your help understanding this, i now understand the example give at http://blog.fogus.me/2010/09/27/unifycle-a-unification-library-for-clojure/
13:44	mudge	gfrlog: yes, i see that it tries to get rid of every variable if it can
13:44	gfrlog	mudge: good. The complicated part is when a variable occurs more than once within an expression
13:45	gfrlog	that constrains the unifyer to match the same thing in both instances
13:45	mudge	gfrlog: that is interesting
13:45	gfrlog	the primary context I've encountered unification in is natural language processing
13:45	mudge	gfrlog: was it helpful?
13:46	mudge	gfrlog: it would be interesting to see cases where a unifier would be useful
13:46	gfrlog	mudge: to the folks doing it, I'm sure :) I was just taking a class
13:46	dnolen_	gfrlog: mudge: unification is central to logic programming of all kinds.
13:47	mudge	gfrlog: now I have taken a class in unification, so thanks
13:47	kephale	mmm… unification is one of the more sophisticated logic-based pattern matching techniques
13:47	gfrlog	mudge: in NLP, the sort of structures handled were features of works, like tense, person, number, etc.
13:47	gfrlog	the unification would happen when a rule of the language said that two words had to "agree" to some extent
13:47	dnolen_	https://gist.github.com/1083967
13:48	dnolen_	^ unification allows this tiny bit of code to type check, type reconstruct, and even produce the terms that satisfy the types.
13:49	mudge	dnolen_: interesting
13:50	mudge	I guess it is useful enough to go into clojure.core
13:51	dnolen_	mudge: you can build knowledge bases, http://stackoverflow.com/questions/6713424/how-do-i-express-this-logic/6719627#6719627
13:51	kephale	can anyone point me to the place in the clojure source where binding expressions are evaluated for things like {:keys […]}, (:syms […]}
13:52	gfrlog	kephale: open the clojure.core source and grep for :syms? :)
13:53	gfrlog	kephale: one occurence: https://github.com/clojure/clojure/blob/f86db9cc68773dd3e4a166c1ff7b81e4a98aa602/src/clj/clojure/core.clj#L3403
13:55	kephale	gfrlog: aha, thanks. I've been using {:keys […]} a lot, so I figured I should know how that code works.
13:55	gfrlog	kephale: looks complicated to me :)
13:56	gfrlog	kephale: you know it's equivalent to {foo :foo, bar :bar, ...}, right?
13:58	kephale	gfrlog: yes, but I could probably take advantage of that a bit better and generate a map like that instead
13:58	lnostdal-laptop	..and another thing with 1.3; why doesn't it assume these-things are dynamic after printing a warning? .. it defaults to the non-safe option
13:59	gfrlog	lnostdal-laptop: it defaults to the new behavior
13:59	gfrlog	lnostdal-laptop: it'd be pretty weird if it changed its behavior based on the structure of your symbol
13:59	lnostdal-laptop	it should default to the new behavior, but not when the *'s are used .. it should warn (as it does) then, and do the safest thing ...
13:59	lnostdal-laptop	based on history; not really
14:00	gfrlog	clojure 1.2 doesn't change its behavior based on the structure of your symbol
14:00	gfrlog	it's just a naming convention
14:00	lnostdal-laptop	i know this
14:00	lnostdal-laptop	there everything was the same
14:00	lnostdal-laptop	that's not the issue ofc.
14:00	lnostdal-laptop	using non-dynamic variables is an optimization
14:01	mudge	why is core.unify in the list of 1.3 Contrib projects when it is part or going to be part of clojure.core ?
14:01	mudge	https://github.com/clojure/core.unify
14:01	lnostdal-laptop	i mean using them by default . .one that potentially breaks things and it certainly breaks things like-these more than once
14:01	gfrlog	lnostdal-laptop: in 1.2, all vars are assumed to be dynamic. in 1.3, all vars are assumed to be not dynamic.
14:01	lnostdal-laptop	yes, i know this, gfrlog ..
14:02	gfrlog	lnostdal-laptop: I think it might have been better called 2.0, because of all the breaking changes
14:02	lnostdal-laptop	but it warns based on naming style in 1.3 .. and it should also fall on the safe side after printing that warning
14:02	gfrlog	but I _don't_ think it should start examining your code for naming conventions and changing its behavior based on them
14:02	mudge	the list of Contrib projects is here: http://dev.clojure.org/display/design/Contrib+Projects
14:02	mudge	and core.unify is listed there for some reason
14:03	kephale	gfrlog: (fn keys-map [m] (zipmap (keys m) (map keyword (keys m))))
14:03	gfrlog	kephale: yes?
14:04	kephale	just noting what I ended up with
14:04	lnostdal-laptop	(..the reason it should fall on the safe side of things is that this would lead to waaay less breakage..)
14:05	gfrlog	lnostdal-laptop: why doesn't the warning take care of that?
14:06	gfrlog	lnostdal-laptop: what you're proposing is a much more complicated change
14:06	chrissbx	Is there a "=" that returns false for separately allocated objects with the same contents? (pointer equality comparison)
14:06	Chousuke	identical?
14:07	chrissbx	Thanks
14:07	gfrlog	&(identical? (hash-map 4 5) (hash-map 4 5))
14:07	lazybot	⇒ false
14:07	chrissbx	Is there a "=" that only works for numbers, i.e. complains if the arguments are not numbers?
14:08	gfrlog	probably not. You could write your own with a precondition.
14:08	Chousuke	hm
14:08	Chousuke	isn't that ==
14:08	Chousuke	,(doc ==)
14:08	clojurebot	"([x] [x y] [x y & more]); Returns non-nil if nums all have the same value, otherwise false"
14:08	gfrlog	,(== () ())
14:08	clojurebot	java.lang.ClassCastException: clojure.lang.PersistentList$EmptyList cannot be cast to java.lang.Number
14:08	gfrlog	I learn more if I assume I know the answers to all the questions and then get corrected.
14:09	chrissbx	Perfect, thanks.
14:09	gfrlog	Chousuke: does == do anything that = doesn't?
14:10	chrissbx	Well it asserts the types.
14:10	chrissbx	Useful for error checking.
14:10	gfrlog	:\| That hardly seems like a reason to include a separate function in core
14:10	gfrlog	what if I want a version of assoc that only accepts maps?
14:11	chrissbx	Equality predicates are especially sensitive to the type issue, since they silently return false in buggy cases.
14:11	gfrlog	hmm
14:12	gfrlog	it still only solves one instance of the problem
14:12	gfrlog	what if I want an == for keywords?
14:13	chrissbx	Agreed.
14:13	chrissbx	Other lisps still prominently provide number comparison, though.
14:13	chrissbx	Maybe because math is especially likely to break?
14:13	chrissbx	Whatever. I'm happy for the ==.
14:14	dnolen_	,(= 1 1.0)
14:14	clojurebot	true
14:14	gfrlog	dnolen_: I even tried it with a ratio
14:14	dnolen_	this behavior is changed in 1.3.0
14:14	dnolen_	(= 1 1.0) is now false
14:14	dnolen_	(== 1 1.0) is now true
14:14	gfrlog	oh geez
14:14	chrissbx	heh:)
14:15	gfrlog	can we please pull a Torvalds and call it 2.0? there's still time.
14:15	chrissbx	Maybe that was the reason :)
14:15	gfrlog	this is embarrassing
14:15	gfrlog	it's not just poking at the big-ints anymore
14:16	dnolen_	gfrlog: these changes have been sitting around for like 8 months, plenty of time to get used to it.
14:16	dnolen_	threads galore on the ML and here on rationale
14:16	gfrlog	dnolen_: for those who are paying attention maybe
14:16	gfrlog	just because there's a reason to break things doesn't mean you shouldn't indicate it in your numbering
14:17	dnolen_	gfrlog: if you think 2.0 and 1.3.0 distinction is significant. bikeshedding non-sense IMO.
14:19	gfrlog	dnolen_: so why do we have dotted version numbers at all? why not just increment an integer whenever something changes?
14:20	dnolen_	gfrlog: there's discussion on the ML about this as well, I don't have much more to say about it.
14:20	gfrlog	dnolen_: okay I'll go look. thanks.
14:20	lnostdal-laptop	it sure does have breaking changes
14:21	dnolen_	lnostdal-laptop: so did the other releases.
14:21	lnostdal-laptop	i guess 1.2.0 --> 1.2.1 didn't, then
14:22	gfrlog	dnolen_: in arithmetic?
14:25	chrissbx	What's the standard way to open a file for input (or output), to get at the stream.
14:26	gfrlog	chrissbx: check in clojure.java.io
14:28	chrissbx	Thanks
14:29	raek	chrissbx: clojure.java.io/{input,output}-stream for binary (byte based) files and clojure.java.io/{reader,writer} for text (character based) files
14:37	chrissbx	I'm getting "java.io.BufferedReader cannot be cast to java.io.PushbackReader" when using reader with read
14:43	raek	yeah, you have to wrap the result of reader with (PushbackReader. )
14:43	chrissbx	Aha.
14:43	raek	there isn't any function for that in clojure.java.io unfortunately
14:44	chrissbx	Weird, it seems to me that reading s-expressions from a file would be one of the most standard things a Lisp system would do.
14:45	chrissbx	I'm finding myself not only implementing a read-all, but also binding java to get the offered functions from two clojure libraries to work together.
14:45	VT_Entity	there's no easier way?
14:46	chrissbx	Why is '`a evaluated to (quote user/a) and not to (quasiquote a)? Is quasiquote expanded by the reader, or is quasiquote still evaluated at macro expasion time but does quote not prevent macros from being evaluated?
14:48	VT_Entity	I think quasiquote means hold off until the macro is invoked.
14:49	VT_Entity	so, you can still shuffle around the code as data until you invoke the macro.
14:49	VT_Entity	I could be wrong though, still new at this.
14:54	raek	chrissbx: it is expanded by the reader
14:55	chrissbx	In other lisps, (quote expr) means that expr is treated as a literal constant, i.e. unmodified. So I was expecting the result of (quote (quasiquote a)) to be (quasiquote a) as it is in Scheme.
14:56	chrissbx	Now I guess Clojure "mangles" the symbols in the reader (to add the namespace to them), whenever it sees quasiquote.
14:57	gfrlog	how do I run the tests in a clojure/maven project like clojure.java.jdbc?
14:57	gfrlog	`mvn test` doesn't seem to find anything to do
14:57	VT_Entity	I think you need to explicitly invoke auto gensym, no?
14:58	raek	,(read-string "`foo")
14:58	clojurebot	(quote sandbox/foo)
15:14	gfrlog	forking project, changing, compiling with maven, uploading to clojars: very hard.
15:23	gfrlog	I guess it's more the fact that I was doing two libs at the same time
15:23	gfrlog	and don't know how to use clojure/maven
15:25	amalloy	chrissbx: reading files into s-expressions is pretty easy with slurp + read-string
15:28	chrissbx	amalloy: I need all expressions, so I wrote a read-all, but that expects a stream as an argument
15:28	chrissbx	read-string only reads 1 expr
15:29	chrissbx	Also, why slurp the whole file into memory when reading expressions lazily from a stream would do.
15:30	chrissbx	But if you meant to say that read-string and slurp are the reasons that the rest is totally incomplete, then I see the point.
15:32	gfrlog	so after an hour of furious patching I finally got clojure.java.jdbc + clojureql to read lazy result sets from mysql
15:33	chrissbx	gfrlog: interesting; when I last looked at the mysql protocol (or was it just libmysql?) about 5 years ago, it didn't support lazy reading of result sets.
15:33	amalloy	gfrlog: "I learn more if I assume I know the answers to all the questions and then get corrected." so true
15:33	gfrlog	amalloy: :)
15:34	gfrlog	chrissbx: apparently it supports it if you pass particular arguments to [prepare\|create]Statement, and then do this hacky thing with fetchSize
15:34	chrissbx	Ok, will have to look at it some time. Thanks for the hints.
15:34	gfrlog	amalloy: it registers in my brain as embarrassment, which subconciously motivates me to remember
15:34	gfrlog	...or suppress
16:00	StayInSkool	hi #clojure! what are good examples of (simpler for starters) open-source clojure (and compojure) apps to learn from?
16:01	StayInSkool	so far I've found either really basic or rather complex examples
16:01	amalloy	StayInSkool: https://github.com/dbyrne/4clojure ?
16:03	StayInSkool	amalloy: hmm, that sounds like a good starting place. thanks!
16:04	amalloy	StayInSkool: and feel free to bug us (okay, mostly just me these days) in #4clojure if you need some hints
16:06	StayInSkool	thanks :D
16:10	seancorfield	clojure.java.jdbc 0.0.4 on maven central - fixes reflection warnings, fixes transaction handling on Error thrown, code cleanup
16:11	seancorfield	gfrlog: sounds like you had some problems with c.j.j?
16:11	seancorfield	i use it with mysql all the time - anything i can do to help?
16:11	seancorfield	or was it more around clojureql (which i don't use i'm afraid)?
16:14	gfrlog	seancorfield: it was regarding reading a ResultSet lazily
16:15	gfrlog	apparently the mysql driver only does it if you add some arguments to (.prepareStatement ...)
16:15	gfrlog	seancorfield: so I did this kind of thing: https://github.com/USCSoftware/java.jdbc/commit/7f9d45d2e88b82a4d28b706b4ebe8696827348ef
16:15	seancorfield	ah, i'm working on exposing machinery to allow users to operate on the PreparedStatement before it is executed
16:16	gfrlog	seancorfield: that might do the trick, I haven't looked at the methods on PreparedStatement to see if the configuration can be done _to_ it as well
16:17	seancorfield	yeah, it may need just exposing as a way to pass in a function that creates the PreparedStatement appropriately
16:17	seancorfield	whoever design the Java API for the JDBC stuff should be taken out and shot - it's horrible to work with!
16:18	lucian	seancorfield: why not use clojureql?
16:19	gfrlog	i patched clojureql as well; it creates its statements on its own
16:19	seancorfield	lucian: i maintain clojure.java.jdbc
16:19	lucian	oh
16:19	seancorfield	yeah, clojureql is kinda standalone
16:20	seancorfield	i tried it but didn't really like the approach
16:20	lucian	i see
16:20	seancorfield	at world singles we have some pretty gnarly joins and stuff and it was not very intuitive to read the clojureql forms for those
16:21	seancorfield	also, since i'm introducing clojure to an existing project and the team all know SQL, using c.j.j was a much easier transition for them
16:25	gfrlog	seancorfield: a simple first-try could be to allow (with-query-results) to take a PreparedStatement as well as a vector
16:25	lucian	right
16:32	seancorfield	that means the calling code has to do the uglies with the connection to create the PreparedStatement - i think i'd rather pass a map of parameters that the code uses to figure out the right call of .prepareStatement on the connection...
16:34	amalloy	seancorfield: isn't the point here that the client wants to do something complicated? better to let them do it, when they want control
16:35	seancorfield	yeah, it's a matter of making a clean interface for the most common needs
16:35	seancorfield	i haven't decided quite what's best yet
16:37	seancorfield	passing a map of {:type :forward-only :concur :read-only :fetch-size Integer/MIN_VALUE} seems like a nicer approach than making the user deal with the java directly, yes?
16:40	amalloy	seancorfield: that sounds fine, i'm sure. i don't really know what's going on here in general, but it seems to me like you should also give them a way to pass you an actual object they built, in case there's some feature you don't expose
16:41	seancorfield	yes, probably that too
17:28	ihodes	(def π (Math/PI))
17:28	ihodes	,(def π (Math/PI))
17:28	clojurebot	DENIED
17:30	amalloy	&(let [π (Math/PI)] (* 2 π))
17:30	lazybot	⇒ 6.283185307179586
17:52	chrissbx	Hm. I'm looking for a way to reformat Clojure code (wrapping and indentation); clojure.pprint has been suggested to me, but how am I supposed to make it indent it right?
17:52	chrissbx	Isn't there something that would just do it out of the box?
17:53	chrissbx	I've already written a Clojure printer in my Scheme-to-Clojure converter, if I'll have to figure out all rules to make the Clojure code wrapped and indented right myself anyway,
17:53	chrissbx	I can just as well add this to my printer.
17:55	chrissbx	(With the added benefit that I wouldn't be tied to using Clojure / the JVM as part of the conversion.)
17:55	chrissbx	Yes, sounds like I could as well go that route;
17:55	chrissbx	except that I don't know any emacs code that does the wrapping.
17:56	technomancy	yes, that's trickier. so far I've punted on wrapping.
17:56	_simonf	Hola - my first day using clojure. I'm having trouble seeing the clojure.contrib.math jar that I put in ~/.clojure. Running "CLOJURE_EXT=~/.clojure java -cp /usr/local/downl/clojure/clojure/clojure.jar clojure.main" does not help.
17:57	chrissbx	It seems a bit funny to me how much stuff Scheme systems got done that the Clojure community doesn't seem to have solved yet.
17:57	technomancy	chrissbx: is it really all that surprising? scheme has had many, many more decades.
17:58	chrissbx	I still find it surprising, because my impression is that there are more people using Clojure than all the Scheme systems together, but maybe that's a wrong impression.
17:59	technomancy	_simonf: you might have a better time starting at http://dev.clojure.org/display/doc/Getting+Started
17:59	chrissbx	Thing is that most Scheme systems got things like these implemented independently, each with only a tiny community.
17:59	technomancy	_simonf: any time you're invoking "java" directly you're probably making things more complicated than they need to be, and there are a lot of bad docs out there, including clojure.org
18:00	_simonf	technomancy: yeah, I already stumbled into bad docs
18:01	chrissbx	Also, of course it's funny because Hickey could just have made Clojure a dialect of Scheme and borrowed much code.
18:01	chrissbx	But then it wouldn't have been new and people wouldn't have flocked to it maybe. Dunno.
18:01	_simonf	technomancy: yeah, I already stumbled into bad docs is about IDEs, which is less interesting. My Ubuntu's clojure is old, so I figured I'll build the jars from github.
18:01	chrissbx	Anyway, back to writing code.
18:02	technomancy	clojurebot: lein tutorial?
18:02	clojurebot	lein is http://github.com/technomancy/leiningen
18:02	technomancy	_simonf: ^^ I recommend starting there.
18:03	technomancy	building the jars by hand can be a bit of a rabbit trail
18:04	_simonf	technomancy: I'm not sure what you mean. I use vim, so this page tells me to use vimclojure, which is a syntax highlighter. Does not tell me anything about getting the actual language.
18:05	technomancy	_simonf: generally it's coupled with a build tool
18:06	technomancy	http://lisp4fun.blogspot.com/2010/02/leiningen-and-vimclojure.html might be relevant
18:09	Scorchin	_simonf: lein gives you a simple build tool to hide away many of the issues involved with loading jars. It also simplifies a number of common tasks such as loading up your app into the repl, compiling, running tests and packaging
18:10	_simonf	trying now...
18:15	raek	_simonf: re your original problem: clojure.contrib.math is not included in clojure itself, so you need to add [org.clojure/clojure-contrib "1.2.0"] as a dependency in your project.clj and run "lein deps" to fetch it
18:15	raek	(assuming you are using clojure 1.2.0 or 1.2.1)
18:16	_simonf	raek: yup, I just figured this out
18:16	Scorchin	raek: He wasn't using lein to begin with. He's switching to use it now though, so that should be extremely useful!
18:16	_simonf	looks like in 1.3 individual contrib libraries are split out
18:16	_simonf	it's not clear how to specify them individually in project.clj
18:19	technomancy	_simonf: I don't know if math has been upgraded to 1.3 yet
18:19	technomancy	if you're starting out you should use the latest stable release, not the betas
18:25	_simonf	ok, I got the compile cycle working, but this means I lost the REPL mode. I have to rebuild my jar after every edit
18:31	raek	_simonf: while developing its more common to keep a repl open and reload files when you change them instead of doing the compile cycle
18:31	_simonf	raek: ok
18:32	raek	it's simpler to develop in the repl if you think of the source files as holding the definitions of the functions you use in the repl (or in the -main function) rather than a script that is executed
18:33	raek	_simonf: if you have a file in src/myproject/core.clj, you can load it and enter its namespace with (doto 'myproject.core require in-ns)
18:33	raek	use (require 'myproject.core :reload) to reload it
18:33	amalloy	(which is shorthand for (require 'myproject.core) (in-ns 'myproject.core)
18:34	raek	for this to work you should also have a (ns myproject.core) at the top of the source file
18:34	lnostdal-laptop	hm, i guess using transients inside agents won't do since agents execute using any random thread from a pool?
18:34	_simonf	hm - so I have to know which files I want to reload
18:34	_simonf	in the Python world, I'm mostly developing by running unittests until they pass
18:35	_simonf	that seems to minimize overhead
18:35	brehaut	_simonf: (use :reload-all 'namespace)
18:36	brehaut	_simonf: or you could run lazy test which watches your source files and reloads them and runs tests automatically
18:37	brehaut	_simonf: or lein interactive
18:37	amalloy	lnostdal-laptop: yeah, i'm afraid so
18:37	_simonf	awesome, reload-all works. Thank you everyone!
18:38	_simonf	I must say, Clojure is easier to get into than Haskell
18:38	amalloy	you'd need to allocate a future and manage it yourself
18:52	ihodes	_simonf: Haskell is awesome though--i think you need just a bit more activation enegery with Haskell than you do with clojure to get going
18:52	tufflax	Hm, why it this so slow http://pastebin.com/bVHRKaKz
18:55	tufflax	is*
18:56	amalloy	tufflax: you're boxing and unboxing integers a lot
18:56	tufflax	ok, how can i avoid that
18:57	tufflax	not use an int array?
18:57	amalloy	typehints in the appropriate places, except i don't know what places those are. dnolen will know
18:58	bsteuber	tufflax: which clojure version?
18:58	tufflax	1.2.1
18:58	bsteuber	expect 1.3 to be a lot faster in these things
18:58	tufflax	ok, thats nice
19:34	haploid	can defn define sequential execution without let, dorun, etc ?
19:35	brehaut	((fn [x] (prn "x is" x) (inc x)) 1)
19:35	brehaut	,((fn [x] (prn "x is" x) (inc x)) 1)
19:35	clojurebot	"x is" 1
19:35	clojurebot	2
19:35	brehaut	haploid: ^
19:36	brehaut	haploid: long version: functions have an implicit do
19:36	brehaut	haploid: dorun is quite different to do
19:36	haploid	ok, cool, thanks
19:40	haploid	one other thing - does anyone know off the top of the head what "simpledb.core" is? trying to understand the noir-blog source, but google is not helpful here with understanding what the dependencies are/do
19:43	brehaut	haploid: perhaps an api for amazon's simpledb ?
19:45	haploid	yeah, could be, except the main libraries for simpledb in clojure appear to be "sdb" and "rummage" - and it wouldn't make sense that the noir folks would make having an aws account mandatory to run their example app.
19:45	haploid	weird
19:46	brehaut	haploid: https://github.com/ibdknox/simpledb
19:47	brehaut	haploid: its a trivial in memory db
19:47	brehaut	that serializes to a file using clj forms
19:47	haploid	ah awesome, thanks.
19:47	haploid	wonder why google couldn't find it.
19:48	brehaut	presumably because amazon's simpledb is much more talked about
19:48	brehaut	and google isnt friendly to precious code-ish queries (by default anyway)
19:49	brehaut	s/precious/precise/
19:49	lazybot	<brehaut> and google isnt friendly to precise code-ish queries (by default anyway)
19:57	Scriptor	there's always google code search
19:59	gfrlog	seancorfield: I left before the discussion with amalloy. I support both options -- I think your idea is good because the java.sql interface is pretty limited, so it might be that there's only a small set of things somebody could do anyhow. But amalloy's idea is good in principle, and probably can't hurt.
20:00	brehaut	and in this case knowing to check ibdknox's github
20:15	StayInSkool	what's the point of doing something like (fn add-five [x] (+ x 5)) 3) ?
20:16	StayInSkool	isn't that still an anonymous function? what's the point of add-five?
20:16	gfrlog	StayInSkool: you can recurse
20:16	StayInSkool	oooooh
20:16	StayInSkool	like in javascript
20:16	gfrlog	StayInSkool: true true
20:17	StayInSkool	perfect, thanks!!
20:17	gfrlog	no probalo
20:17	Scriptor	,(class (defn foo [] "foo")
20:17	clojurebot	EOF while reading
20:17	Scriptor	,(class (defn foo [] "foo"))
20:17	clojurebot	DENIED
20:18	gfrlog	Scriptor: come on man you know it ain't gonna let you def nuthin
20:18	Scriptor	:(
20:18	gfrlog	it's a var right?
20:33	amalloy	gfrlog: yes, clojurelang.Var
20:33	gfrlog	amalloy: what was the thing I was going to say to you if you were around?
20:35	amalloy	$help mail
20:35	lazybot	amalloy: Send somebody a message. Takes a nickname and a message to send. Will alert the person with a notice.
20:35	gfrlog	amalloy: a notice? when?
20:36	amalloy	gfrlog: next time they're spotted logging in or saying something
20:36	gfrlog	so if they're already logged in then it waits till they say something?
20:36	amalloy	$mail gfrlog like so
20:36	lazybot	Message saved.
20:36	gfrlog	come on lazy bot what did he want to tell me?
20:36	gfrlog	oh I bet it's in some other erc window
20:36	gfrlog	damn you emacs
20:37	amalloy	yeah he PMs you. mails are definitely not public
20:37	amalloy	C-x b lazybot, probably
20:37	gfrlog	not seeing anything there actually
20:37	amalloy	hm
20:37	amalloy	$mail amalloy test
20:37	lazybot	Message saved.
20:37	amalloy	test test
20:38	gfrlog	$mail amalloy giggle
20:38	lazybot	Message saved.
20:38	amalloy	gfrlog: well you were wrong, he PMs me just fine
20:38	amalloy	errr, except i didn't get that one. puzzling
20:38	gfrlog	PM here stands for Prime Minister, right?
20:39	amalloy	oh, interesting. apparently he won't notify you of new mail more than once every five minutes
20:39	amalloy	but you can still read them by sending him the message "mail"
20:39	gfrlog	ah there got it for the first time
20:40	gfrlog	maybe cuz I used '/msg lazybot ...'
20:40	gfrlog	and erc likes that
20:40	amalloy	dunno
20:40	gfrlog	I'm not going to technomancy's emacs talk, so I will never learn how all this works.
20:46	amalloy	grrrr. i love clojure, but exception-handling is often so much easier with mutable state
20:48	technomancy	amalloy: is it really mutable state you want, or just more flexible exception types?
20:49	amalloy	technomancy: i'm not sure. i suspect there'd be an easy way to do it with slingshot, but since i'm not used to having better exceptions i'm not sure what it would be
20:50	amalloy	my current problem is i need to react in similar ways to a number of different conditions. i'm calling into a library which throws a "dumb" exception, and if it does i need to include part of my current environment (a loop binding) in the eventual result
20:51	amalloy	which sounds like either making that binding a mutable semi-global, or catching the internal exception and then throwing something different
20:51	technomancy	nah, slingshot can include the local context as part of the exception
20:52	amalloy	so, catch the dumb exception, and then throw a smart one which will automatically have local context bundled into it?
20:52	technomancy	oh, I didn't catch (har) that a separate library was throwing
20:53	technomancy	yeah, it's awkward when you have this divide between your code and dumb exception land
20:53	technomancy	which I feel is part of why error-kit and c.c.condition didn't take off
20:53	amalloy	i mean, the library is clojail, which i have write access to. but either way, it wouldn't have access to the calling code's environment in order to include into the exception
20:54	technomancy	it sounds like chaining may be the way to go... and it sounds like that would be true in a mutable system too
20:54	amalloy	technomancy: chaining as in re-wrapping the exception?
20:55	technomancy	right
20:55	amalloy	i don't even need to throw an exception. i know how to handle the error, i just have to unify the various error cases
20:56	amalloy	maybe i can just rewrite this whole function. it's pretty gross anyway
21:21	zakwilson	Something that's awesome about Clojure is that the usual programming advice of hiding the underlying implementation and exposing an unchanging API is a little different. Usually, the API and underlying implementation can just be based around Clojure data structures, and if the implementation changes those data structures still make a reasonable API.