#clojure – 2012-06-09

2012-06-09

00:09	muhoo	eslick_: thoughtworks is the only big shop i know of that does clojure in the bay, but there may be others
01:17	johnmn3	what does it mean that "Can only recur from the tail position" ??
01:17	lazybot	johnmn3: Uh, no. Why would you even ask?
01:17	johnmn3	The recur is the last expression within the scope of the doseq
01:20	hiredman	doseq has no return value, it has no tail
01:20	johnmn3	ah
01:20	johnmn3	yea, I'm trying loop now
01:21	hiredman	you cannot recur across loops
01:21	johnmn3	oh?
01:21	hiredman	how would recur know which loop to recur to?
01:22	hiredman	(loop [] (loop [] (recur)))
01:23	johnmn3	well, I'm not nesting two loops
02:09	johnmn3	I'm currently doing a (.read on an input stream, which gets sent to (.write on a FileOutputStream.
02:09	johnmn3	Now, I want to instead write that to a datastructure
02:16	Sgeo_	If basic math things such as sin rely on interop, does this reduce the number of libraries that work both on Clojure and ClojureCLR?
03:04	amalloy	Sgeo_: you can always choose to rely instead on a library like clojure.math that provides a layer of indirection to the underlying libraries
03:12	borkdude	can I see which libraries on clojars use netty?
03:12	borkdude	and how?
03:12	brehaut	http://clojuresphere.herokuapp.com/netty
03:13	borkdude	brehaut great tnx ;)
04:35	tomoj	is there a nicer way to do (fn [sep & args] (join sep args)) ?
04:35	tomoj	I feel like it should be obvious..
04:38	borkdude	just use join?
04:38	AimHere	join takes a seperator and a list of string
04:38	AimHere	*strings
04:38	borkdude	ah
04:38	AimHere	He wants just a list of stuff, the first one being the seperator
04:39	borkdude	of course
04:39	amalloy	i don't think so, tomoj
04:39	amalloy	you can generalize, though, and then use your general tool
04:39	borkdude	there is no ~@ in functions ;-)
04:39	AimHere	Well you can just give that fn up there a name, then it's the generalization
04:40	tomoj	strange
04:40	tomoj	it doesn't already have a name?
04:41	borkdude	wait ~@ has nothing to do with it ;; I'm still sleepy...
04:41	tomoj	hmm
04:41	tomoj	I guess it doesn't generalize well
04:41	ejackson	tomoj: interpose ?
04:41	amalloy	((fn listify [f arity] (fn [& args] (apply f `(~@(take arity args) ~(drop arity args))))) join 1)
04:42	tomoj	seems weird though
04:42	ejackson	,(apply str (interpose ":" ["Hello" "My" "Honey"]))
04:43	clojurebot	"Hello:My:Honey"
04:43	amalloy	ejackson: that's just join
04:43	amalloy	&(((fn listify [f arity] (fn [& args] (apply f `(~@(take arity args) ~(drop arity args))))) clojure.string/join 1) "," 1 2 3 4)
04:43	lazybot	⇒ "1,2,3,4"
04:43	amalloy	now listify is the general case, and you can easily apply it to join
04:43	ejackson	and so it is
04:46	tomoj	what does that do with arity 0?
04:46	amalloy	it's probably just (f args)
04:46	amalloy	or rather (comp f list)
04:47	tomoj	yeah
05:00	ejackson	is there a function for: (#(assoc % :key (f %)) map) ?
05:00	ejackson	like update-in, but taking the whole map, rather than a particular key as argument ?
05:04	tomoj	no. (assoc map :key (f map)) is shorter than that though..
05:05	tomoj	depends on what the map is named I guess :)
05:06	ejackson	ejackson's-baroquely-named-mega-map, for instance ?
05:08	ejackson	agreed, its in that form as I'm mapping it over a seq of maps (I do this a lot)
05:52	notsonerdysunny	while I am able to run clj project that imports a java-class file.. I am having trouble getting it to work with slime .. it keeps reporting that it cannot find the class file when I try to compile the file using C-c C-k does any of you have a suggestion
05:52	notsonerdysunny	I am able to successfully do lein jar
05:52	notsonerdysunny	or lein uberjar
05:52	notsonerdysunny	or lein run
05:53	notsonerdysunny	just unable to work with it using slime..
06:06	PKHG	hallo, good morning form (NL) (just 2 minutes left ;-) ).... how can I display the conten of jar from out a REPL?
06:14	PKHG	lazybot: how to ping all listeners?
06:14	PKHG	&"how to ping several people"
06:14	lazybot	⇒ "how to ping several people"
06:15	PKHG	&(* 1234567 88986868686868)
06:15	lazybot	java.lang.ArithmeticException: integer overflow
06:15	PKHG	&(* 1234567 88)
06:15	lazybot	⇒ 108641896
06:16	borkdude	&(*' 1234567 88986868686868)
06:16	lazybot	⇒ 109860251514140566156N
06:17	borkdude	,(doc *')
06:17	clojurebot	"([] [x] [x y] [x y & more]); Returns the product of nums. () returns 1. Supports arbitrary precision. See also: "
06:19	PKHG	borkdude: how to look at the conten of a *.jar from within a repl?
06:19	PKHG	oh and hallo to you ;-)
06:19	borkdude	PKHG maybe take a look at this library: https://github.com/Raynes/bultitude/blob/master/src/bultitude/core.clj which lists the namespaces from a jar file
06:19	PKHG	thanks will look now ;-)
06:20	borkdude	PKHG if you are familiar with the Java API for doing this, you can work it out probabl
06:20	PKHG	borkdude: lovely complicated for a newbie
06:20	PKHG	Java was last century for me ;-(
06:20	borkdude	PKHG I don't have a ready answer, just some pointers on how to get started maybe ;)
06:21	PKHG	will look at the script ...
06:21	PKHG	trying to use it ..
06:23	borkdude	PKHG maybe this answer on StackOverflow also contains some useful pointer: http://stackoverflow.com/questions/5171957/access-file-in-jar-file
06:23	PKHG	yes the last example ... trying too ;-)
06:27	PKHG	thanks .. have to leave ..
08:39	cshell	Saturday, the best day to do all of your at-home development!
09:41	clj_newb	Hi, any suggestion on how to read large files ? is duck-stream the best cho? Or go straight to a BufferedReader?
09:43	ejackson	clj_newb: http://richhickey.github.com/clojure/clojure.java.io-api.html is a good choice.
09:43	lazybot	Nooooo, that's so out of date! Please see instead http://clojure.github.com/clojure/clojure.java.io-api.html and try to stop linking to rich's repo.
09:43	ejackson	sorry lazybot
09:43	clj_newb	thank you ejackson
09:43	clj_newb	no offense if I go to where the bot suggest hehe
09:44	ejackson	yes, I pasted before I looked
10:00	Crackneck	hello can someone please help a noob understand the recur exprs* (http://clojure.org/special_forms#Special%20Forms--(recur%20exprs*) I not sure how to read that function so that i makes sense
10:02	AimHere	Crackneck, it's not something you really need to know THAT much about if you're a complete noob, in that it's just an optimization
10:02	Crackneck	im just goiing throug the clojure learning tool koans
10:02	Crackneck	it's one of their questions
10:02	Crackneck	now i could just copy that code
10:02	AimHere	What it is is that when you're call a function, arguments get pushed onto the stack and the return value gets popped when you return
10:02	Crackneck	but that would be stupid =)
10:03	mthvedt	the recur syntax is like a function call, except instead of calling a function you jump to the nearest recursion point
10:03	AimHere	So if you recurse heavily, your stack might grow too big, which might use up vast amounts of memory
10:05	AimHere	If you can write your function so that the return value is in the 'tail position' (i.e., it's not being changed after the recursion call) then you can skip past all this pushing and popping
10:05	Crackneck	mthvedt ok, and the recursion point in that example is the loop?
10:06	mthvedt	yup
10:06	AimHere	Right, it's either the enclosing 'loop' or the enclosing function call
10:07	Crackneck	ok, and the "tail" position is the line with only " acc "
10:07	AimHere	nah, the tail position is the call to 'recur'
10:07	mthvedt	multiple positions in a form can be "tail"
10:08	babilen	Hi all -- I need some help with a most likely quite trivial data-transformation. I've detailed it on https://www.refheap.com/paste/3065 and would be greateful for any pointers.
10:08	mthvedt	tail position only means the compiler can wrap up all computation before executing the recur
10:09	AimHere	Crackneck > You can think of it as (defn f [cnt acc] (if (zero? cnt) acc (f (dec cnt) (* acc cnt))) as a factorial function of n, called with (f n 1)
10:09	Crackneck	that helped AimHere, thanks
10:10	Crackneck	not being sarcastic
10:10	Crackneck	i guess I just got confused by the big words
10:11	Crackneck	tail and recursion point
10:11	Crackneck	both new stuff to me
10:11	AimHere	Essentially it's just rewriting functions in a funny way because it means they don't eat up lots of memory
10:12	Hali_303	hi! is there a built-in average function?
10:12	Crackneck	yes i am familiar with the concept, just not the clojuresk implementation
10:13	babilen	Hali_303: Not AFAIK, but it is easy to implement it as https://www.refheap.com/paste/3066
10:13	Hali_303	babilen: yeah I know, I just see no point in everybody implementing it..
10:15	babilen	Any ideas concerning https://www.refheap.com/paste/3065 ? -- I am really not sure where to start :-/
10:17	cshell	babilen: Just create a map with the values in your vector as thte keys
10:17	cshell	and always use the (first) for the value?
10:19	babilen	cshell: Well essentially I want to count how often "relN" co-occurs with "patN" and have both number easily accessible in two maps. One that maps { rel → { pat → #occurrences}} and the other { pat → {rel → #occurrences}}
10:21	cshell	babilen: Right, so a basic function will be switching them around into key value
10:21	cshell	then you can call that for each sequence and take the result and merge it into a map that counts
10:22	babilen	cshell: Ok, I am currently working on an approach that just creates tuples (patN, relN) from the input. Any better idea for the switching?
10:24	cshell	I think that could work as well and then just count all the tuples, right?
10:26	babilen	Well, group-by first and then count the tuples that have been grouped together. Strikes me as not very elegant, but meh ..
10:34	AimHere	Couldn't you just have a frequency table of [relN patN]?
10:55	tmciver	Could someone tell me what the '[&] here means: https://github.com/cgrand/moustache/blob/master/src/net/cgrand/moustache.clj#L120 ?
11:00	raek	tmciver: that's a part of the moustache route syntax.
11:00	raek	["foo" &] matches all urls that begin with /foo/
11:01	raek	it is explained in the moustache github readme
11:01	tmciver	raek: yes, but is that syntax meaningful outside of moustache? ##((apply array-map [:a 1 :b 2]) '[&])
11:01	lazybot	⇒ nil
11:02	raek	tmciver: what does 'forms' look like there?
11:03	raek	it has no special meaning in clojure
11:03	tmciver	raek: Ah, I think I'm getting it. One of the keys in the resulting array-map may be [&].
11:03	raek	it just means look up the value for the key which is a vector of the symbol &
11:03	tmciver	OK, it makes sense to me now. Thanks for helping me to think straight.
11:04	tmciver	##((apply array-map [[&] "hello" :a 1]) '[&])
11:04	lazybot	java.lang.RuntimeException: Unable to resolve symbol: & in this context
11:05	tmciver	hmm, maybe not.
11:05	raek	&((apply array-map ['[&] "hello", :a 1]) '[&])
11:05	lazybot	⇒ "hello"
11:05	raek	&((apply array-map [[(symbol "&")] "hello", :a 1]) '[&])
11:05	lazybot	⇒ "hello"
11:06	tmciver	yes
11:06	raek	symbols are treated as variables when evaluated
11:06	tmciver	or ##((apply array-map ['[&] "hello" :a 1]) '[&])
11:06	lazybot	⇒ "hello"
11:06	babilen	AimHere: I was thinking about that as well. The problem is that I also would like to be able (without much computational overhead) to know which pats co-occur with which rels and vice versa. The datastructures that I have in mind just allow me to use (keys (get pat FOO {})) to get that and I can still easily have the frequency as well.
11:06	tmciver	raek: thanks again.
11:43	babilen	cshell: I am using https://www.refheap.com/paste/3067 but find it overly complicated. What was your initial intuition regarding the switching key <-> values?
11:43	horofox	Hi guys, I want to know why does "(= (:a :b :c :d :e) (cons :a '(:b :c :d :e)))" raise IllegalArgumentException?
11:43	horofox	I'm doing the clojure koans
11:44	babilen	horofox: Try " (= '(:a :b :c :d :e) (cons :a '(:b :c :d :e)))" (you missed a ' for the first list)
11:44	babilen	horofox: It also makes sense to read the complete error, which would have been "IllegalArgumentException Wrong number of args passed to keyword: :a ..." -- It is clear that :a is called as a function here, which you obviously don't want.
11:45	horofox	babilen: IllegalArgumentException Wrong number of args passed to keyword: :a clojure.lang.Keyword.throwArity (Keyword.java:85)
11:45	horofox	babilen: I'm still getting the same error
11:45	horofox	;/
11:45	babilen	&(= '(:a :b :c :d :e) (cons :a '(:b :c :d :e)))
11:45	lazybot	⇒ true
11:46	babilen	Note "(= '(:a" vs "(= (:a"
11:46	horofox	oh lol
11:46	horofox	i'm so dumb
11:46	babilen	I'd argue that you are rather blind than dumb :-þ
11:46	horofox	:P
11:47	horofox	what are good uses of clojure?
11:47	babilen	Those errors are always horrible and hard to track down.
11:47	horofox	I'm not really used to fp and using ' to construct lists so like... i don't have the "eye" to this kind of stuff yet
11:48	cshell	horofox: concurrency, general programming, etc
11:48	horofox	cshell: projects that use it?
11:48	cshell	horofox: the ' just tells it not to evaluate the form - without it it thinks you're making a function call
11:48	horofox	babilen: with hadoop?
11:48	thmzlt	babilen: have some of that code to show?
11:49	cshell	horofox: Websites, some financial industry code, various others - all the work that relevance does I think
11:49	babilen	thmzlt: Nothing public yet
11:49	horofox	cshell: oh, so it's not a abbreviation to list? i wouldn't know if you didn't tell me, thanks!
11:49	antares_	horofox: Twitter Storm is a distributed data crunching framework, much like hadoop. There are also cascalog (Cascading + Datalog, a query language) by the same authors, I think. They have been using Clojure with Hadoop for years.
11:49	horofox	cshell: which website is made in clojure?
11:50	horofox	antares_: oh i see
11:50	cshell	horofox: correct, it tells the reader to just read in whatever follows instead of trying to evaluate
11:51	cshell	horofox: Some other people can better answer that, but a clojure website is no different than any other website from the browser perspective - I've written some websites in Clojure
11:51	rlb	horofox: '(foo) is shorthand for (quote (foo))
11:52	rlb	And lists have to be quoted so that they're not evaluated as a function call (as mentioned above).
11:52	horofox	cshell: I do a lot of web development and work with it atm(i work on a startup with rails). Does clojure have anything that speeds up web development or can scale/is fast?
11:53	antares_	horofox: http://webnoir.org
11:54	cshell	horofox: that's what i use, noir
11:54	antares_	Noir is a bit more towards Django in some design decisions and it definitely is "lower level", like Sinatra
11:54	horofox	antares_: is it very fast?
11:54	horofox	antares_: would it fit well for say, an API?
11:55	antares_	for example, you don't need any "engines", it supports loading views (actions) + templates and stuff from a .jar, so you can create embeddable Web apps
11:55	cshell	horofox: not much of an api needed - just defpage and defpartial
11:55	antares_	horofox: JSON API is its sweet spot
11:55	cshell	I use enlive as templating over hiccup
11:55	antares_	cshell: noir.response/json is probably what most people would try first for APIs (just saying)
11:55	antares_	horofox: as for performance, it is very low level and runs on JVM app servers
11:56	antares_	a small Noir app without any optimizations does 10K+ requests per second on 100 MBit/s and 4 core machine
11:56	cshell	ah, got it
11:57	horofox	nice
11:57	antares_	horofox: I am not trying to make any "Ruby cannot scale" kind of claims but check out this: http://blog.beanstalkapp.com/post/23998022427?acd86ee0, after using Ruby since 2006 or so, I can confirm that you generally see this kind of difference once you get around writing decent Clojure code HotSpot can optimize
11:58	antares_	horofox: so Noir and Clojure are probably as close to Sinatra/Ruby as it gets, if you don't take Python (same category as Ruby) or JRuby into account
11:58	horofox	antares_: oh, i've seen this post. this looks good
11:59	antares_	horofox: if you are looking for data store clients, clojure.java.jdbc, http://sqlkorma.com, Carmine (for Redis) and http://clojurewerkz.org libraries have you covered
11:59	antares_	as for templating, there are several Clojure-based templating languages but I use Mustache (with Stencil or Clostache)
12:00	horofox	antares_: cool, so there's a ecosystem in clojure for web development it seens :P
12:00	antares_	while I use Clojure primarily for non-Webapp services, I have been using Noir with Mustache for 2 days straight now and really enjoy testability and minimalism
12:00	antares_	horofox: honestly, a lot of Clojure projects need good docs
12:01	horofox	antares_: i wanted to join the "data crunching" crowd, i think in the following years it's going to be big.
12:01	antares_	but good maturing projects are certainly there and JVM ecosystem gets you a ton of good stuff almost for free
12:02	antares_	horofox: I can't say I am doing that much data crunching. Primarily NLP, Web crawlers, "background" services. But we will soon start a new project where the Web part will be in Clojure, too (after 6 years of using Ruby)
12:02	horofox	antares_: so you are some months ahead of me hehe :)
12:03	antares_	horofox: oh, and there's also http://immutant.org
12:03	horofox	antares_: I wanted to try some nlp with clojure also :P
12:03	antares_	much like TorqueBox for Ruby
12:03	horofox	thats cool... 0.1.0 hehe
12:04	antares_	there are 1-2 year old projects that are still 0.2.0 or so in Clojure
12:05	antares_	for some reason people are very conservative about numbering
12:05	antares_	we start with 1.0.0-alpha1 for http://clojurewerkz.org and announce things at about rc1
12:05	horofox	hehe
12:05	antares_	but none of that 0.1.0 or 0.0.1 stuff
12:05	antares_	there are awesome libraries that are at 0.0.9
12:05	antares_	I mean, come on, plenty of people use them, they are several months old
12:05	antares_	and at 0.0.x
12:07	horofox	i see hehe!
12:07	horofox	i just want to see how i'm going to get used to fp :P
12:08	horofox	antares_: how long have you been studying clojure?
12:08	horofox	or fp
12:09	antares_	Clojure is not as strict as Haskell, for example. If you want to do I/O semi-randomly, go for it, just don't use it inside STM transactions. TheJust as example. Monads and all ther CS theory stuff is entirely optional, too.
12:09	antares_	horofox: I used Scala prior to Clojure for ~ 1 year
12:09	antares_	and now almost 1 year with Clojure
12:10	antares_	picked up some erlang and haskell along the way, too
12:10	antares_	I think in 2-3 months you will be comfortable enough to notice what works better and learn from other people's code
12:11	antares_	it may be just 4-5 weeks if you have someone experienced around to help you and point out what you are doing wrong or where you can just use a core library function instead of writing your own thing
12:11	horofox	antares_: yea, that's what i want. I'm doing the koans and then I'm going to start with the clojure book.
12:11	horofox	antares_:
12:11	horofox	antares_: woops, hehe.
12:12	antares_	but I may be an exception, I never worried about prog lang syntax and FP in general fits my brain well (I find it easier than all that OO patterns stuff that keeps layering abstractions upon abstractions)
12:12	antares_	horofox: I've never done koans but I heard good things about them
12:12	antares_	also, 4clojure.com
12:13	antares_	I jumped into Clojure by developing a couple of libraries I needed when I decided I've had enough CRuby scaling pain
12:15	horofox	antares_: i see. i'm going to check 4clojure out
12:31	eslick	Anyone have a sense of tradeoffs in using regular maps vs. records when pulling records from a document DB?
12:32	eslick	I have a web app which pulls data from mongodb, does some modest transformations on it, then pushes it over HTTP to the client
12:32	eslick	I use a :type field to dispatch various common methods on all those objects today
12:33	eslick	I like the documentation benefits of clearly defining protocols over types, but it didn't seem worth the performance overhead.
13:23	clj_newb	Hi, can I retrieve a default value when nil from a map I mean (def n {:a 1 :b 7}) and when (:c n) since it'll return nil assign a number
13:25	morphling	,(doc get)
13:25	clojurebot	"([map key] [map key not-found]); Returns the value mapped to key, not-found or nil if key not present."
13:25	hoeck	clj_newb: of course you can: (:c {} 'foo)
13:29	clj_newb	thank you
14:28	clj_newb	,(doc if-let)
14:28	clojurebot	"([bindings then] [bindings then else & oldform]); bindings => binding-form test If test is true, evaluates then with binding-form bound to the value of test, if not, yields else"
15:15	Sgeo_	Hmm.
15:15	Sgeo_	Auto-gensyms are implementable in CL, right?
15:17	Vinzent	Sgeo_, I guess so
15:19	cmajor7	how do I call this from clojurescript (with jayq): $("[rel=tooltip]").tooltip({placement: 'bottom'}); ?
15:19	cmajor7	this does not work: (.tooltip ($ "[rel=tooltip]") "{placement: 'bottom'}")
15:24	bobry	cmajor7: you can use js-obj function, (.tooltip ($ "[rel=tooltip]") (js-obj "placement" "bottom"))
15:26	raek	I haven't used clojurescript much yet, but I think you need to access global js functions via the js "pseudo namespace": (js/$ ...)
15:26	cmajor7	bobry: thanks. that compiles as: "jayq.core.$.call(null, "[rel=tooltip]").tooltip(jayq.core.js_obj.call(null, "placement", "bottom"));" and gives "TypeError: Cannot call method 'call' of undefined"
15:26	bobry	raek: i think it's a function from jayq, not a global jQuery function
15:26	bobry	ah, then raek's advice is relevant
15:27	bobry	hmm, js-obj didn't work, this is weird
15:27	bobry	it should've been compiled as {placement: "bottom"}, which version of cljs this is?
15:28	cmajor7	well "call" itself on the $ does not cause the problem
15:28	cmajor7	jayq.core.$.call(null, "[rel=tooltip]").tooltip(); works
15:28	bobry	yup, it's js-obj
15:28	cmajor7	clojurescript-0.0-993.jar
15:28	bobry	weird thing is '(js-obj "foo" "bar")' works for me in the repl
15:29	bobry	but it's the latest clojurescript from maven repo
15:29	bobry	can you update to 1236?
15:30	cmajor7	just updated to "clojurescript-0.0-1011.jar", I am going through noir-cljs
15:31	cmajor7	let me try to update noir-cljs to the latest alpha
15:33	Sgeo_	Does CLR (not necessarily ClojureCLR) support TCO?
15:34	cmajor7	bobry: how do I start a repl to be in sync with all the server deps, so I can try '(js-obj "foo" "bar")'? I am just "lein repl" it in the root, but the deps are not loaded into repl
15:35	bobry	cmajor7: i use 'cljsbuild' plugin https://github.com/emezeske/lein-cljsbuild
15:35	bobry	and then start the repl with 'repl-rhino' subcommand
15:36	bobry	but frankly, this repl is pretty much useless -- no auto completion, no readline, hangs on exceptions etc
15:36	bobry	it's okay to try a one liner though
15:41	cmajor7	you mean: "lein trampoline cljsbuild repl-rhino" ?
15:43	eggsby	Sgeo_: not sure about .net and tail call optimization, generally clojure tends towards tail call elimination via loop/recur
15:45	Sgeo_	Has SICP for Clojure gotten anywhere?
15:45	Sgeo_	Or should I just use the Scheme version
15:48	bobry	cmajor7: yup
15:50	cmajor7	bobry: thx. I added ":plugins" and ran "lein deps" but it does not see those task past trampoline, anything obvious I missed?
15:51	bobry	cmajor7: not sure, is cljsbuild in .lein-plugins directory?
15:52	cmajor7	nope..
15:53	cmajor7	ok.. trying manually: lein plugin install lein-cljsbuild 0.2.1
15:54	cmajor7	seemed to work => ""ClojureScript:cljs.user>
15:54	bobry	good :)
15:55	cmajor7	ClojureScript:cljs.user> (js-obj "foo" "bar")
15:55	cmajor7	(js-obj "foo" "bar")
15:55	cmajor7	did that mean it works in REPL?
15:55	bobry	what did it output?
15:55	bobry	also, why don't you try lein2? it's much-much nicer
15:55	cmajor7	the input :)
15:55	bobry	hmmm, not sure :)
15:55	bobry	I have [Object ...]
15:55	cmajor7	what does it output in your repl?
15:56	bobry	try (.-foo (js-obj "foo" "bar")), it should output "bar"
15:58	diki_	hey everyone
15:58	diki_	just a quick sanity check, if you don:
15:58	ldopa	is http://dev.clojure.org/jira/browse/LOGIC-8 back in core.logic 0.7.4 or do i not understand how tabling works?
15:59	diki_	just a quick sanity check, if you don't mind:
15:59	diki_	(ns sanity-check.core
15:59	diki_	(:use [quil.core :exclude [noise]]))
15:59	diki_	should not complain if i try do defn noise, should it?
16:05	cmajor7	bobry: yep, it did indeed
16:05	bobry	then I guess it works :)
16:06	cmajor7	but "(.tooltip ($ "[rel=tooltip]") (js-obj "placement" "bottom"))" still fails
16:06	bobry	with the same error message?
16:06	cmajor7	yep: ""EcmaError: TypeError: Cannot call method "call" of undefined (<cljs repl>#4)
16:07	bobry	well, no wonder it fails in the repl, it's not a 'browser-connected repl'
16:07	bobry	so it doesn't know about $ and .tooltip method
16:08	raek	if $ is a js function (jquery or not) I still think you need js/$
16:08	bobry	raek: https://github.com/ibdknox/jayq
16:09	cmajor7	bobry: it fails in the browser too, I just tried it in REPL as well
16:10	cmajor7	jayq.core.$.call(null, "[rel=tooltip]").tooltip(jayq.core.js_obj.call(null, "placement", "bottom"));
16:10	cmajor7	TypeError: Cannot call method 'call' of undefined
16:12	bobry	hmm, does jayq.core.$ return a jQuery object?
16:12	raek	oh.
16:12	bobry	oh
16:12	bobry	js_obj is still resolved incorrectly
16:14	cmajor7	bobry: jayq.core.$ returns a function
16:14	cmajor7	(and it does work)
16:15	cmajor7	it is the last part (e.g. with {placement: 'bottome'}) that does not
16:15	cmajor7	*bottom
16:15	bobry	yes, it is the last part, because js-obj call should've been expanded to {"placement": "bottom"} during compilation
16:15	bobry	i wonder why it wasn't
16:31	zaka	how can i count all the values of a map to eachother? For example i have the map {:a 1 :b 2 :c 5} then I want the answer to be 8
16:31	AimHere	&(reduce + (values {:a 1 :b 2 :c 5}))
16:31	lazybot	java.lang.RuntimeException: Unable to resolve symbol: values in this context
16:31	Sgeo_	zaka, I think there's a function to... okh
16:31	AimHere	&(reduce + (vals {:a 1 :b 2 :c 5}))
16:31	lazybot	⇒ 8
16:32	Sgeo_	AimHere, reduce is pretty much Haskell's foldl1?
16:32	AimHere	Pretty much
16:32	Sgeo_	&(reduce (list))
16:32	Iceland_jack	Sgeo_: reduce is foldl and fold
16:32	lazybot	clojure.lang.ArityException: Wrong number of args (1) passed to: core$reduce
16:32	AimHere	You could use 'apply' instead if you like
16:32	Sgeo_	&(reduce + (list))
16:32	lazybot	⇒ 0
16:32	lpvb	foldl'?
16:32	Sgeo_	&(reduce cons (list))
16:32	lazybot	clojure.lang.ArityException: Wrong number of args (0) passed to: core$cons
16:33	Sgeo_	Ah, I see how it behaves with empty sequences, I.. think
16:33	AimHere	&(reduce conj '() '(1 2 3 4))
16:33	lazybot	⇒ (4 3 2 1)
16:33	Iceland_jack	&(doc reduce)
16:33	lazybot	⇒ "([f coll] [f val coll]); f should be a function of 2 arguments. If val is not supplied, returns the result of applying f to the first 2 items in coll, then applying f to that result and the 3rd item, etc. If coll contains no items, f must accept no arguments as... https://www.refheap.com/paste/3070
16:33	Iceland_jack	It can take 2 or 3 parameters
16:34	Jayunit100	hmm so we are finding that clojurescript isn't interpreted ?
16:35	Jayunit100	i.e., its not interpreted in the browser.
16:35	adu	you mean speed-wise?
16:35	Jayunit100	well ….. was trying to interpret some simple clojure, in the browser
16:36	Sgeo_	How does ClojureScript development compare to http://amber-lang.net/ ?
16:37	Sgeo_	As in, are there nice ClojureScript REPLs that run on the webpage and result in savable Javascript?
16:38	Jayunit100	yeah -- that's what i thought i could use clojurescript for
16:38	zaka	thanks everybody!
16:42	Jayunit100	how is the IRC interpreter secured ?
16:43	Jayunit100	,(print "security?")
16:43	clojurebot	security?
16:44	metellus	I think it uses clojail https://github.com/flatland/clojail
16:45	Sgeo_	What's the difference between , and &?
16:45	Sgeo_	With the bot
16:45	hiredman	~sandbox
16:45	clojurebot	sandbox is http://calumleslie.blogspot.com/2008/06/simple-jvm-sandboxing.html
16:45	metellus	they trigger different bots
16:45	hiredman	~source
16:45	clojurebot	source is http://github.com/hiredman/clojurebot/tree/master
16:45	Raynes	clojurebot uses a different sandbox.
16:45	Raynes	lazybot uses clojail
16:45	Raynes	Which is also what tryclj and 4clojure use.
16:46	Raynes	And the difference between then is that they're entirely different bots.
16:47	Sgeo_	Ah
16:47	Sgeo_	Why two bots?
16:48	amalloy	Sgeo_: why not?
16:50	Sgeo_	Are there restrictions to how hot-swappable Clojure can be?
16:50	Sgeo_	I've heard about this ClassLoader thing but don't know anything about it :
16:50	Sgeo_	:/
16:53	Raynes	Sgeo_: Because I got board a couple of years ago and wrote a bot and it happened to end up with features that clojurebot doesn't have that some people like.
16:53	Raynes	bored*
16:54	Raynes	And two bots means that if one goes down, there is always a backup. :)
17:15	cmajor7	"Could not locate crate/def_macros__init.class or crate/def_macros.clj on classpath" => seems to be a dependency issue between "noir-cljs" and "crate". anybody knows what is the latest working version combination?
17:20	zomg	Is there some meaning to using ;; as comments as opposed to just a single ; ? I see ;; occasionally but not sure why use it if ; works too
17:20	hiredman	;; is for block comments (on their own line)
17:21	hiredman	(+ 1 2) ; is for comments that follow code
17:21	clojurebot	3
17:21	zomg	Ah I see
17:21	hiredman	and that is how it has been since the dawn of time
17:21	Raynes	You can use ; for block comments, but I'll find you if you do.
17:22	zomg	Raynes: yeah I noticed it works like that too so was just wondering :D
17:22	zomg	I guess it's just a coding style thing
17:30	amalloy	http://www.gnu.org/software/emacs/manual/html_node/elisp/Comment-Tips.html
19:41	horofox	how do i do this koan?
19:41	horofox	"But they are often better written using the names of functions"
19:41	horofox	(= 25 (___ square)))
19:42	ohpauleez	horofox: is square def'd to 5?
19:43	horofox	yep
19:43	horofox	ohpauleez: yep
19:43	AimHere	So can't you just insert a function that turns 5 into 25?
19:44	horofox	Well, could do (= 25 25)
19:44	horofox	I could do*
19:44	horofox	but I'm not learning that way, hehe
19:44	ohpauleez	#(* % 2)
19:44	horofox	I need to fix the __
19:44	raek	horofox: so in this case you want the __ function to return its argument unchanged?
19:45	ohpauleez	gah - #(* % square)
19:45	horofox	I don't know what I want, this is the koan.
19:45	ohpauleez	So it's hinting to you
19:45	ohpauleez	Functions can be anonymous - without names
19:45	raek	horofox: is "square" 5 or 25?
19:46	ohpauleez	(fn [arg] (* arg arg))
19:46	ohpauleez	or shorthnd #(* % %)
19:46	horofox	oh, square is: (defn square [n] (* n n))
19:46	horofox	I just need to fill the blanks
19:47	ohpauleez	If that's what square is, then the blank has to do with the threading macro
19:47	ohpauleez	->
19:47	raek	ok, so your task is to write a function that takes a function (let's call it f) and applies it to 5
19:47	horofox	Given (defn square [n] (* n n)) and "But they are often better written using the names of functions" and (= 25 (___ square))) and I need to fill the blank
19:47	horofox	no, my task is to fill the blanks :P
19:47	horofox	the __
19:47	raek	(fn [f] (f 5))
19:48	horofox	raek: why your answer is correct? :P
19:48	raek	if you call that with square, you get ((fn [f] (f 5)) square) → (square 5) → 25
19:48	horofox	my head exploded
19:48	horofox	:(
19:49	ohpauleez	(= 25 (-> 5 square))
19:49	raek	any part of an expression can be a variable, including the function
19:49	ohpauleez	or rake's solution
19:49	ohpauleez	which was the first suggestion
19:49	ohpauleez	raek**
19:51	raek	I still don't understand what they mean by "But they are often better written using the names of functions" though... :)
19:51	horofox	Same :(
19:51	ohpauleez	Right, that made more sense when I assumed square was 5
19:51	horofox	where did you guys learn functions?
19:51	ohpauleez	not a function
19:52	horofox	I still can't get it right
19:52	ohpauleez	horofox: what language are you coming from, or is this your first?
19:52	horofox	oh I've been coding for 12 years but never got into fp
19:52	horofox	(= 25 (fn [f](f 5) square)))
19:52	horofox	why is that wrong?
19:53	ohpauleez	you're missing some parens
19:53	horofox	where?
19:53	clojurebot	where is your source code
19:53	ohpauleez	(= 25 (#(% 5) square))
19:53	zomg	Hm, what is the correct way to call a function multiple times with different args, and collect the results as a list? Eg. (map (Math/sqrt) [1 2 3]) which obviously does not work
19:53	horofox	(defn square [n] (* n n)) and (= 25 (fn [f](f 5) square)))
19:54	zomg	Should I just use an anonymous function eg #(Math/sqrt %) ?
19:54	ohpauleez	(= 25 ((fn [f] (f 5)) square))
19:54	raek	horofox: but functions are so simple. to evaluate a function call, like (defn g [a b] (+ a b)) (g 1 2), you replace the call with the function body, substuting the actual parameters (1 and 2) for the formal parameters (a and b): (+ 1 2)
19:54	zomg	Coming mostly from a Haskell background where you can just toss functions into map like that and it works without making it a lambda or such =)
19:54	tmciver	zomg: ,(map #(Math/sqrt %) [1 2 3])
19:55	zomg	Okay, as I thought then. Thanks!
19:55	tmciver	zomg: ##(map #(Math/sqrt %) [1 2 3])
19:55	lazybot	⇒ (1.0 1.4142135623730951 1.7320508075688772)
19:55	metellus	horofox: you need "fn [f] (f 5)" inside parens
19:55	metellus	,(= 25 ((fn [f](f 5)) square))
19:55	clojurebot	#<CompilerException java.lang.RuntimeException: Unable to resolve symbol: square in this context, compiling:(NO_SOURCE_PATH:0)>
19:55	raek	horofox: does it make more sense if I write it like this? (defn square [n] (* n n)) (defn call-with-five [f] (f 5)) (= 25 (call-with-five square))
19:56	AimHere	zomg > most of the time, you'd have something like (map sqrt [1 2 3]). Math/sqrt is just some java function instead of a clojure one, so it's not really a first class citizen
19:56	horofox	horofox: wait, trying to understand :P
19:57	zomg	AimHere: Right, so it would work if it was a Clojure function? I see
19:57	horofox	raek: I still didn't
19:57	AimHere	Well what you initially wrote put the function in parentheses, which would evaluate the function with no arguments
19:57	horofox	raek: do you have any article?
19:57	zomg	AimHere: yeah :) And omitting them would cause an error for static field
19:58	ohpauleez	horofox: In clojure (and other languages), functions are first-class - like ints, doubles, strings, etc
19:58	AimHere	That's just a piece of ugliness caused by clojure sitting on top of Java
19:58	ohpauleez	you can pass them around, return them, apply them
19:59	ohpauleez	this koan is trying to show you (in a rather silly way) how that happens
19:59	horofox	ohpauleez: i see, but I don't think I really got it so I can move on :P
19:59	ohpauleez	in Clojure, the first thing in a paren is always a function *[except in the ns macro]
20:00	AimHere	Well it might be a macro or a special form
20:00	amalloy	ohpauleez: if you're going to make an exception, i don't know why you would choose the ns macro
20:00	ohpauleez	AimHere: true, but for the stage he's at, we can get by with a sweeping generalization to solidify the point
20:00	horofox	ohpauleez: Ok I got it...
20:01	ohpauleez	amalloy: because it's commonly seen
20:01	horofox	ohpauleez: It's throwing a function inside another function that solves that thrown function?
20:01	horofox	which solves*
20:02	horofox	ohpauleez: is there a name for this kind of pattern so I can research more about it?
20:02	ohpauleez	horofox: first-class functions
20:03	ohpauleez	also anonymous functions, lambda functions
20:03	raek	horofox: higher order functions
20:03	ohpauleez	also that
20:03	raek	(i.e. functions that take functions as parameters or return functions)
20:04	raek	horofox: this is a good book where you can learn more: http://mitpress.mit.edu/sicp/full-text/book/book.html
20:04	ohpauleez	horofox: And here's an article http://www.ibm.com/developerworks/java/library/j-ft1/index.html
20:04	zomg	Man the JS generated by ClojureScript is pretty darn messy :P
20:04	AimHere	The main trouble with sicp is that you have to get familiar with another Lisp
20:05	zomg	Admittedly the clojure code is more concise than the equivalent JS code
20:05	raek	horofox: or more specifically: http://mitpress.mit.edu/sicp/full-text/book/book-Z-H-12.html#%_sec_1.3
20:05	ohpauleez	zomg: What do you mean? It's coming out of an optimizing compiler, it's not a 1-to-1 transpolar like CoffeeScript
20:05	AimHere	I don't mind the js being messy, what I hate is that I get js errors instead of clojure ones
20:05	ohpauleez	transpiler*
20:06	raek	this book uses scheme, but it is similar enough to clojure for learning basic functional programming patterns you can use in clojure, I think
20:06	AimHere	Yeah, it's transferable
20:06	AimHere	Mostly
20:07	zomg	Yeah with CS the output is at least more what you'd write yourself
20:07	zomg	But obviously CS is more 1 to 1 with JS than Clojure is so perhaps it's not a reasonable expectations with this case
20:07	zomg	But things like this: var x__48689 = cljs.core.nth.call(null, vec__48687__48688, 0, null);
20:08	zomg	Guh. =)
20:08	zomg	For starters what's with the .call there.. Completely unnecesary as far as I can tell.
20:09	zomg	I'm just nitpicking since I'm primarily someone who writes JS along some other stuff so it's just bugging me a bit =)
20:15	amalloy	zomg: do you worry about the assembly code your C compiler writes? why does it matter what javasript the cljs compiler outputs?
20:16	zomg	Sometimes you're going to need to look at it to figure out why it isn't working
20:16	zomg	But yeah it's not that big of a deal
21:34	devn	,(range 0 -10 -1)
21:34	clojurebot	(0 -1 -2 -3 -4 ...)
21:34	devn	,(range 0 -10 0)
21:34	clojurebot	(0 0 0 0 0 ...)
21:34	devn	,(range 0 10 0)
21:34	clojurebot	()
21:34	devn	This bothers me.
21:34	devn	,(range 0 0 0)
21:34	clojurebot	()
21:41	hacliff	Hey, anyone here use sublimetext for their editor? Trying to replicate emacs C-c C-e for eval
21:52	zomg	Man it feels like I'm probably completely mis-using atoms and mutation...
21:52	zomg	=)
21:53	zomg	I've got a value which needs to be changed from a function call as it will affect the subsequent calls, but it also must sometimes get reset to 0... so I've def'd an atom which gets reset! into the values it needs
21:55	zomg	There's all this bindings and whatever else there is but this seemed like the most straightforward way to go about it :P In Haskell I probably would've used a State monad or something
21:56	devn	zomg: you have a value, like 1, and you need it to change, but you dont want it to change for subsequent callees?
21:57	devn	zomg: oh, nvm
21:58	devn	zomg: could you just use loop/recur or (for... or something? does this process go on forever? Is it a lazy seq?
21:58	zomg	http://jjh.fi:8080/~jani/editor-cljs/src-cljs/editor/core.cljs <- this is the mess I have, the relevant functions are load and handle-drag
21:59	devn	'([1 :x] [2 :y] [3 :z], [1 :b] [2 :c] [3 :d], ...) for instance
21:59	zomg	on the last line of load there are two lambdas, the first one is called when dragging, the second when dragging starts
22:00	zomg	when dragging starts, the value needs to be reset to 0, and then it later gets changed when the handle-drag function gets called while the drag is being performed
22:00	zomg	The code works but it doesn't seem to be the correct way to go about doing this =)
22:02	zomg	It seems like using binding might be a better way for it since I think def is making 'sx' a global... at least in the generated JavaScript code it is marked into editor.core.sx
22:03	devn	zomg: that was sort of my initial thought
22:07	zomg	devn: good, then it seems I'm not totally lost =) thanks
22:09	devn	zomg: wish i could offer more. i see your dilema, but it sure feels like some information is being propagated using the atom that doesnt need to be
22:09	devn	then again you might be overthinking it :)
22:09	zomg	Possibly
22:09	devn	anyway, im off, godspeed
22:09	zomg	Typically with JS I'd just stick it into a variable which is shoved into a closure with the rest of the junk accessing it
22:10	zomg	But thought I might as well use Clojure for this as a challenge and a learning experience =)
22:16	Sgeo_	"In OO languages, another purpose of encapsulation is to prevent object A from modifying or corrupting the private data used by object B.
22:16	Sgeo_	In Clojure, this problem does not exist. Data structures are immutable. They cannot possibly be corrupted, or changed in any way, period. You can write query functions that return “private” state, without any fear of data corruption."
22:16	Sgeo_	http://thinkrelevance.com/blog/2009/08/12/rifle-oriented-programming-with-clojure-2
22:17	Sgeo_	What about when something is an implementation detail, and you want to prevent consumers from relying on it being there
22:17	Sgeo_	You wouldn't want it to be readable (easily), because if it was, someone might rely on it and it might not work in the future
22:17	nDuff	Sgeo_: both convention and documentation work for that
22:17	Sgeo_	Can't break the object, but it would break the client.
22:17	nDuff	Sgeo_: that's true of Clojure itself, for that matter
22:18	Sgeo_	Hmm, what convention?
22:18	nDuff	Sgeo_: ...more of Clojure's internals are exposed than are documented, but any user relying on undocumented behavior is on thin ice
22:18	nDuff	...there actually _is_ support for marking vars (with ^:private or defn-)
22:18	nDuff	err, marking vars private
22:19	Sgeo_	What about marking keys on a map?
22:19	Sgeo_	er, key-value pairs I guess
22:19	nDuff	namespacing keys acts as a hint that their values are considered internal
22:19	nDuff	so ::mykey rather than :mykey
22:19	Sgeo_	Ah, cool
22:20	nDuff	(which evaluates to :my-ns/mykey)
22:21	kovasb	can one somehow reify an already-instantiated java object?
22:22	kovasb	vanilla reify will create an object from scratch, but I want to take an object and just add some protocols to it
22:22	Sgeo_	Is there a particular reason that argument lists use vectors and not lists?
22:23	kovasb	Sgeo_: the convention in clojure is to reserve () to indicate function falls
22:23	kovasb	calls
22:23	Sgeo_	Ah
22:23	amalloy	Sgeo_: rich's general stance on encapsulation, i believe, is that it's more important to enable good code than to prevent bad code. if someone's not supposed to rely on a particular field, just say so; if they do and then break, that's their problem
22:24	amalloy	kovasb: no, you can't. java doesn't have mixins
22:24	kovasb	amalloy: bummer. what about in clojurescript?
22:25	Sgeo_	I don't know whether to be glad that Clojure uses _ for ignored arguments over CL's (define (ignore blah)), or just react normally since that's what Haskell does
22:25	Sgeo_	erm, declare
22:25	amalloy	kovasb: i dunno. probably not, since its protocols are stored in the prototype chain
22:26	Sgeo_	Does Clojure have something like (declare (ignorable)), so that macros can emit code that depending on circumstance may or may not mention the argument, and either way not trigger a warning?
22:26	kovasb	amalloy: thnx
22:27	amalloy	Sgeo_: i don't understand what you're asking, but the answer is no. not mentioning arguments never issues a warning
22:27	Sgeo_	Hmm, bleh
22:28	amalloy	just like in haskell (i think?), _ meaning "ignored" is just a convention. it's a perfectly legal variable name that you can access if you want
22:30	amalloy	$heval let _ = 1 in _
22:30	lazybot	⇒ Pattern syntax in expression context: _
22:31	amalloy	huh, apparently not
22:31	Sgeo_	$heval let f _ _ = 5 in f (1/0) 2
22:31	lazybot	⇒ 5
22:31	Sgeo_	$heval let f a a = 5 in f (1/0) 2
22:31	lazybot	⇒ Conflicting definitions for `a'Bound at: <interactive>:1:6 <interactive>:1:8
22:32	johnmn3	evenin'
22:32	Sgeo_	Hi
22:36	Sgeo_	If I start learning Clojure, how much Java/about the Java ecosystem will I need to learn?
22:39	kovasb	Sgeo_: depends on the kind of program you want to write
22:39	devn	Sgeo_: you'll pick up what you need to know as you go
22:39	kovasb	Sgeo_: and what the available clojure-only library there are in that domain
22:40	Sgeo_	Any libraries to act as a C FFI?
22:40	Sgeo_	Besides just using the JNI
22:40	kovasb	Sgeo_: in general the "worst" that will happen is needing to look up some javadoc to find some methods
22:41	kovasb	Sgeo_: possible, do some github searching .. :) also there is a project to have a Lua backend for clojurescript, so that should have good c ffi
22:42	devn	Sgeo_: dated, but maybe https://github.com/bagucode/clj-nativ
22:42	devn	https://github.com/bagucode/clj-native
22:42	devn	It could be updated without too much work I think...
22:44	devn	Sgeo_: https://github.com/Chouser/clojure-jna
22:45	Sgeo_	Would it make sense to, as a Clojure project, try rewriting a small Haskell thing in it?
22:46	devn	Sgeo_: sure, if you feel like it, just dont doThisSortOfThing ;)
22:54	Sgeo_	Suppose I want to make an object such that (:x my-obj) runs my own code, i.e., I'm pretending to be a map
22:54	Sgeo_	I know (my-obj :x) would be doable of course... although an answer that ties both together would be more elegant
22:56	Sgeo_	Doing similar with assoc would be even more perfectly, really
22:59	amalloy	Sgeo_: implement Associative and IPersistentMap
22:59	amalloy	maybe ILookup? i forget the exact classes
23:00	amalloy	&(supers (class {}))
23:00	lazybot	⇒ #{clojure.lang.IFn clojure.lang.Associative clojure.lang.IEditableCollection clojure.lang.Seqable clojure.lang.APersistentMap clojure.lang.IObj clojure.lang.AFn clojure.lang.IHashEq java.lang.Runnable clojure.lang.Counted clojure.lang.IMeta clojure.lang.IPersist... https://www.refheap.com/paste/3073
23:00	Sgeo_	AFn?
23:00	technomancy	IPersistentMap might be too specific
23:00	technomancy	ILookup and IFn I believe
23:01	technomancy	IWishItWereClearerWhatToDoHere
23:01	frozenlock	I've got a weird error... Wrong number of args (1) passed to: helperfn$make-trend-log-graph$fn
23:01	frozenlock	[Thrown class clojure.lang.ArityException]. Usually I would say "of course!" and add the missing argument, but in this case I know I have exactly 3 arguments (VS 1 as in the error message). Any idea on what might be causing this?
23:01	amalloy	technomancy: IPM is the one the specifies assoc
23:02	amalloy	no, i guess Associative
23:02	Sgeo_	I guess it's not a very common thing to do
23:03	Sgeo_	Which kind of saddens me -- to my mind it sort of makes sense, to have a sort of getter that is independent of implementation, whether or not it's as a mpa
23:03	Sgeo_	map
23:03	kovasb	Sgeo_: you can use defrecord and get those protocols for free
23:04	Sgeo_	kovasb, and I could override for certain "keys"?
23:04	kovasb	Sgeo_: what would the override do?
23:04	Sgeo_	kovasb, perhaps generate a value based on a function of the values of other keys, when I try to look up on that specific key
23:05	Sgeo_	I guess I'm somewhat thinking of Haskell lenses
23:05	kovasb	Sgeo_: if its a function, why not define it as such?
23:05	Sgeo_	Because for simple things, it sounds like people often use maps
23:05	Sgeo_	And just put stuff in keys
23:06	Sgeo_	So if I were to switch from, say, storing something in a key to it being dynamically generated, I have to change from key to function, meaning that due to an implementation details, client code has to change
23:06	kovasb	i see
23:09	kovasb	yeah, that kind of thing is not a stock datatype, would need to implement yourself
23:10	Sgeo_	I feel like this is sort of a violation of encapsulation :/
23:11	Sgeo_	Hmm.... I feel like maybe this is a project I should take on... although admittedly doesn't seem to large
23:11	Sgeo_	too
23:11	kovasb	you want polymorphism on the content of the argument
23:11	kovasb	not a lot of languages give you that
23:12	kovasb	interesting problem tho
23:13	Sgeo_	Haskell has polymorphism on the return type =P
23:13	Sgeo_	</random>
23:13	kovasb	i mean, its pretty easy to implement what you want from scratch
23:14	kovasb	just use a multi method in the implementation of ILookup
23:15	kovasb	or just a conditional if you are fine with baking the logic in
23:23	lynaghk`	Does anyone know if datomic supports a workflow to and from regular clojure maps? E.g., query, assoc new key/values, transact?
23:24	lynaghk`	From what I can tell, datomic entities don't support assoc, and the best I can do is manually coerce them into hashmaps (making the :db/id an explicit key) and then manipulate and transact that
23:25	kovasb	lynaghk`: https://groups.google.com/forum/#!topic/datomic/fKKz_tg9Bos
23:25	kovasb	lynaghk`: i think thats the extent of general knowledge
23:25	lynaghk`	That feels like too much fighting (especially then special-case ignoring :db/id in all map comprehensions through the rest of my code), so I wonder if I'm missing something
23:25	lynaghk`	kovasb: I saw that (it's easy to read all 60 messages in Datomics mailing list, unfortunately)
23:26	kovasb	lol
23:26	lynaghk`	kovasb: I'm not trying to do anything with arbitrary maps. I just want to manipulate what I've already defined in the schema in a more natural way than juggling vectors of facts manually
23:27	kovasb	i see
23:28	Sgeo_	kovasb, I guess I just need to figure out what the API for making these things would look like
23:28	Sgeo_	Because I now want to make some sort of easy-to-use library
23:34	Sgeo_	Hmm, I guess there could be code that expects a normal map... hmm, actually, so what
23:34	kovasb	(my-thing associative-base {:special-key the-function …})
23:34	Sgeo_	getter would not cause any issues
23:36	Sgeo_	Actually, client might not expect one key to change just because it "changed" another
23:36	kovasb	of course, if the-function returns different values at different times, there could be complications
23:36	kovasb	also, calling assoc on your thing could be problematic :)
23:38	kovasb	if you want to implement lenses, best to just run with that and base the whole thing on reference types
23:38	Sgeo_	reference types?
23:38	kovasb	ref, atom
23:39	kovasb	identities that have values which change over time
23:39	Sgeo_	...why?
23:39	Sgeo_	As in, why not stick with immutable data?
23:39	kovasb	if you thing is changing, then its not immutable
23:39	Sgeo_	"changing" the same way maps "change"
23:40	Sgeo_	i.e. just returning an altered copy
23:40	kovasb	right, but a lens alters multiple things at once
23:41	Sgeo_	Do we have the same notion of lens?
23:41	kovasb	by definition there are at least 2 data structures involved right
23:41	Sgeo_	I don't... think so?
23:42	kovasb	lens transforms between two datastructures
23:43	Sgeo_	Well, hmm, the "setter" portion of a lens still only "modifies" one thing
23:45	kovasb	what is the purpose of the lens then?
23:45	kovasb	at least in the papers, its all about shuffling edits between 2 or more datastructures
23:46	Sgeo_	I don't know if we're referring to different things, or to the same thing and I'm not at that level of understanding
23:46	kovasb	you are talking about lens in haskell?
23:46	Sgeo_	http://hackage.haskell.org/packages/archive/data-lens/2.10.0/doc/html/Data-Lens-Common.html
23:46	Sgeo_	That's pretty much what I'm referring to
23:47	kovasb	unfortunately i can't read haskell
23:48	kovasb	are there examples of actual invocations together with ouput?
23:48	nDuff	Could be talking out my rear here (very much unfamiliar with Haskell concepts), but it smells to me like the sort of thing that might be done with zippers in this world.
23:49	kovasb	the thing i'm referring to as lenses is stuff like this http://dmwit.com/papers/201107EL.pdf
23:50	Sgeo_	getL fstLens (1,2)
23:50	Sgeo_	Would return 1
23:50	kovasb	theres definitely a few implementations of this kind of thing in haskell, but its hard to see exactly what they do
23:50	kovasb	ok
23:50	Sgeo_	setL fstLens 5 (1,2) returns (5,2)
23:50	kovasb	ok
23:51	Sgeo_	Let's say I do
23:51	Sgeo_	Hmm
23:52	Sgeo_	I could define fstLens like so:
23:53	amalloy	last time i heard about lenses (and this setL example reinforces), it seems like they're just a way to implement get-in/assoc-in/update-in in a typesafe way. what's the point of doing them in clojure?
23:53	amalloy	(assoc-in {:left 1 :right 2} [:left] 5)
23:54	Sgeo_	fstLens = lens fst (\pair item -> (item, snd pair))
23:54	Sgeo_	-- fst gets the first element of a pair, snd gets the second element of a pair
23:54	Sgeo_	amalloy, well, I could have different lenses to get and update in different ways
23:56	Sgeo_	Although, might make more sense to tie it in with the datastructure in question
23:56	kovasb	there is some kind of function composition that happens which is different
23:56	Sgeo_	Actually, hmm.... I see what I want to do
23:56	Sgeo_	Instead of keywords for assoc-in and friends, it would make sense to use lenses
23:57	Sgeo_	The thing I linked has mapLens, but that's not a lens
23:57	Sgeo_	Instead, it's a function that takes a key, and gives a lens
23:58	Sgeo_	Should I make an example?
23:58	kovasb	yes :)
23:59	Sgeo_	let myMap = Data.Map.fromList [("a", 1), ("b", 2), ("c", 3)]
23:59	Sgeo_	let aLens = mapLens "a"