#clojure – 2015-09-24

2015-09-24

03:36	craftybones	Hello
03:37	kungi	craftybones: good morning
03:39	craftybones	I'm busy solving a few project euler problems and I want to write a thing where I can something like "lein euler run 1"
04:14	neurostorm	My small webapp eats about 650mb memory, can i reduce this?
04:18	Zeta700	When using the threading operators `->` or `->>` I regularily notice how I want to construct expressions that need mixed positioning of arguments.
04:18	Zeta700	Not always the insertion point of a previous expression should be either the first or last arg.
04:18	Zeta700	Is there an idiomatic solution to this? Am I the only one experiencing it? Demo here: https://www.refheap.com/4be8fdf7f7796e0ae1f763b4a
04:26	luma	Zeta700, there's as->
04:36	Zeta700	luma: ok, I will look into that, thx!
04:38	Zeta700	luma: yes good, that’s it, wasn’t aware of that operator.
04:45	rritoch	If anyone is interested, vinyasa 0.4.2 works on windows. I'm not sure how much time it saves but it will certainly help avoid stress headaches.
07:20	itruslove	are there any clojure events or meetups in London or to the west of london in the next few weeks?
07:25	ane	itruslove: http://www.londonclojurians.org/dojos.html
07:30	itruslove	thanks ane
08:16	justin_smith	luma: Zeta700 already left, but there is also the fact that ->> can be used inside ->
08:28	justin_smith	craftybones already left, but you can specify a namespace to run as an optional arg to lein run, and put each solution in its own namespace "lein run -m euler1" "lein run -m euler2" etc.
08:30	justin_smith	also for project euler you can get away with not using lein for deps "java -jar clojure.jar '(load-file "euler1.clj")'"
08:51	djang0nub	I'm trying to decipher some clojure code - can anyone translate this to java?
08:51	djang0nub	(defmethod generator SetMetaData [^SetMetaData desc overrides] 53 (gen/fmap set (gen/list (generator (.elemMetaData desc) 54 overrides))))
08:51	djang0nub	(defmethod generator SetMetaData [^SetMetaData desc overrides] (gen/fmap set (gen/list (generator (.elemMetaData desc) overrides))))\
08:52	justin_smith	djang0nub: defmethod defines a multimethod dispatch (which is very similar to extending an existing class to an interface with only one method)
08:53	justin_smith	it's saying that if the dispatch for generator returns SetMetaData, run this code
08:53	djang0nub	justin_smith: ok.. so defmethod generator SetMetaData means "generator" method is now being defined for SetMetaData input right?
08:53	justin_smith	djang0nub: right, and usually the dispatch is based on class
08:53	djang0nub	ok
08:54	djang0nub	polymorphism
08:54	djang0nub	wowee
08:54	djang0nub	so what is this funny carat
08:54	justin_smith	(but it doesn't have to be :))
08:54	djang0nub	and desc overrides
08:54	justin_smith	that's a hint to the clojure compiler
08:54	justin_smith	^SetMetaData desc means "desc is probably of concrete type SetMetaData"
08:55	justin_smith	but it doesn't force, coerce, or guarantee this fact
08:55	gilliard	What does it actually do, then?
08:55	justin_smith	tell the compiler what type to expect as the most likely case
08:55	djang0nub	so desc is the first parameter of the function?
08:56	djang0nub	and what is the overrides for
08:56	justin_smith	yes
08:56	justin_smith	djang0nub: overrides is the other argument
08:56	justin_smith	it will break if it gets any number of args other than 2
08:56	djang0nub	ah ok..
08:56	djang0nub	and the .elemMetaData
08:56	djang0nub	what is it dotting
08:56	justin_smith	then it calls gen/fmap with the args set, and (gen/list ... overrides)
08:57	justin_smith	djang0nub: (.foo bar) means call method foo on bar
08:57	justin_smith	as in java methods
08:57	djang0nub	ohh right
08:57	djang0nub	this crazy RPS
08:57	justin_smith	literally (.foo bar) is foo.bar()
08:57	djang0nub	RPN
08:57	djang0nub	ok :)
08:57	justin_smith	and (.foo bar baz) is foo.bar(baz)
08:57	djang0nub	wait is (.foo bar) foo.bar
08:58	djang0nub	or bar.foo()
08:58	djang0nub	bar.foo()?
08:58	justin_smith	djang0nub: argh, just woke up, you are right
08:58	justin_smith	bar.foo()
08:58	justin_smith	or bar.foo - it could be field access
08:58	djang0nub	right.
08:58	djang0nub	makes sense now :D
08:58	djang0nub	ty
08:59	justin_smith	so yeah, (.foo bar) is foo.bar() or foo.bar, and (.foo bar baz) is bar.foo(baz)
08:59	justin_smith	fuck I got it wrong again
08:59	djang0nub	lol
08:59	djang0nub	close
08:59	justin_smith	(.foo bar) is bar.foo()
08:59	djang0nub	this is why lisp scares me
08:59	djang0nub	so many lists
08:59	justin_smith	haha
09:00	justin_smith	djang0nub: in the examples above, the number of parens used is identical between the clojure and java versions
09:00	justin_smith	djang0nub: I got the conversion wrong because I never do the java version
09:01	djang0nub	nice
09:01	djang0nub	I'm trying to decipher this thing to rewrite it in scala
09:01	djang0nub	maybe next i can move to clojure
09:02	justin_smith	my problem, personally, with scala (I know you didn't actually ask) is that there are at least 10 different scalas, so all will be well until you have to read someone else's code, because everyone uses a different mix of the ten languages implemented
09:03	djang0nub	i was almost asking :)
09:03	djang0nub	and its true
09:03	djang0nub	thankfully we are gradually moving towards defining a "sane subset" of the language
09:03	djang0nub	less implicts and magic
09:03	djang0nub	but its still pretty crazy out there
09:04	djang0nub	must be nice on the lisp side
09:04	justin_smith	I think scala has a niche advantage in that it has a version that looks a lot like normal java
09:04	djang0nub	the language is just done
09:04	djang0nub	yeah.. not just looks, you can code in java
09:04	djang0nub	its a great way to ramp up to more FP type stuff
09:04	justin_smith	with lisps you don't spend much time thinking about the language - every blue moon you learn how to use some wacky macro, but that's about it
09:05	djang0nub	that sounds great actually
09:05	justin_smith	djang0nub: with clojure you can write half your code in java as well, interop between java and clojure is very easy in both directions actually
09:06	justin_smith	I'm sure you've learned that's not always the case with other jvm languages
09:06	djang0nub	i know, thats why its the only lisp ill consider learning right now :)
09:06	djang0nub	scala interop is definitely impossible from java side
09:07	justin_smith	it's also tricky from clojure (though I have an unproven suspicion it could potentially be easier from clojure than from java with the right tooling and reflection...)
09:08	djang0nub	hey so does clojure have the capability of implementing crazy functional stuff like type classes or semigroups or dependent types
09:08	djang0nub	more i read scala more i get exposed to these fp ideas, and then peoples horrific hacks to get them to work with scala
09:08	djang0nub	makes me think haskell might be the way to go for pure functional glory
09:08	justin_smith	djang0nub: it's possible but in practice we don't do it, because we are not strongly typed
09:09	djang0nub	omg
09:09	djang0nub	travesty
09:09	justin_smith	though their are monads and lens libraries for those who want to go that route
09:09	justin_smith	*there
09:09	djang0nub	oh now i see why we need the compiler hints
09:09	djang0nub	so its kind of duck typed
09:09	djang0nub	?
09:10	Hacker-Pro	sg Who is here a good Programmer c++ ?
09:10	justin_smith	kind of - it's the bare minimum type restriction demanded by the vm, looser than java even (eg. we don't mess with things like generics at all)
09:10	pbx	djang0nub, you might be interested in http://typedclojure.org/
09:11	dstockton	and then http://blog.circleci.com/why-were-no-longer-using-core-typed/
09:11	pbx	and djang0nub, haskell is the path of purity yes
09:12	djang0nub	ty i will read both of those
09:12	djang0nub	yeah haskell is definitely pure.. i think i may need to be a monk in a monastery for a few months before I'm ready
09:13	djang0nub	gtg, thank you for your help @justin_smith
09:14	justin_smith	np
09:47	phaseNi	Is there a shorthand way tocreate a map from a bunch of variables? Like the reverse of the {:keys [a b c d]} destructuring?
09:48	noncom	phaseNi: how would you like it to look like?
09:49	phaseNi	{:var1 var1 :var2 var2 ...}
09:55	jeremyheiler	phaseNi: maybe you just need this?
09:56	jeremyheiler	,(let [m1 {:a 1 :b 2 :c 3} [:keys [a b c] :as m2]] m2)
09:56	clojurebot	#error {\n :cause "let requires an even number of forms in binding vector in sandbox:"\n :via\n [{:type java.lang.IllegalArgumentException\n :message "let requires an even number of forms in binding vector in sandbox:"\n :at [clojure.core$let invokeStatic "core.clj" 4312]}]\n :trace\n [[clojure.core$let invokeStatic "core.clj" 4312]\n [clojure.core$let doInvoke "core.clj" -1]\n [clojure.lang...
09:57	jeremyheiler	,(let [[:keys [a b c] :as m] {:a 1 :b 2 :c 3}] m)
09:57	clojurebot	#error {\n :cause "nth not supported on this type: PersistentArrayMap"\n :via\n [{:type java.lang.UnsupportedOperationException\n :message "nth not supported on this type: PersistentArrayMap"\n :at [clojure.lang.RT nthFrom "RT.java" 940]}]\n :trace\n [[clojure.lang.RT nthFrom "RT.java" 940]\n [clojure.lang.RT nth "RT.java" 890]\n [sandbox$eval49 invokeStatic "NO_SOURCE_FILE" 0]\n [sandbox$e...
09:57	jeremyheiler	gah
09:57	jeremyheiler	,(let [{:keys [a b c] :as m} {:a 1 :b 2 :c 3}] m)
09:57	clojurebot	{:a 1, :b 2, :c 3}
09:59	jeremyheiler	,(do (def a 1) (meta #'a))
09:59	clojurebot	{:line 0, :column 0, :file "NO_SOURCE_PATH", :name a, :ns #object[clojure.lang.Namespace 0x488e2d88 "sandbox"]}
10:00	jeremyheiler	i don't know how reliable it is to look into the meta for names
10:00	jeremyheiler	for example, let bindings are not vars, so don't have a meta
10:01	snowell	Clojurebot!
10:01	snowell	You're back!
10:05	luma	how about something like this: https://www.refheap.com/109923
10:07	noncom	(inc luma)
10:08	noncom	my version is 5 lines, using reduce, yours is only 3 lines and much simpler
10:12	jeremyheiler	nice
10:25	phaseNi	jeremyheiler: that doesn't save me any typing at all
10:25	phaseNi	:P
10:26	phaseNi	jeremyheiler: thanks though
10:33	rvsv	Does anyone know why I can use a function from a repl but when I call that same function from the running application (java -jar myapp.jar) it causes a stackOverflowError? I'm totally perplexed by this.
10:33	justin_smith	rvsv: are you providing the same arguments?
10:34	justin_smith	could the side effect of printing in the repl be doing something that prevents a stack overflow?
10:34	rvsv	Yeah, exactly the same steps. After it broke in the application I went to the repl and stepped through with the same steps.
10:34	rvsv	Hmm, that I'm not sure about. I'm trying to send an email using postal.
10:35	rvsv	I get a success code in the repl, but in the live application I get the stackoverflow, something for java.io.UnixFileSystem.getBooleanAttributes0
10:36	justin_smith	wait, do you mean stack overflow or stack trace?
10:37	justin_smith	because these are not the same thing at all
10:37	rvsv	It's a stack trace showing a StackOverflowError
10:37	justin_smith	can you paste your stack trace into refheap.com?
10:37	rvsv	sure, just a moment
10:39	rvsv	https://www.refheap.com/109925
10:40	justin_smith	what's your version of postal?
10:40	CookedGryphon	Hey all. Does anyone know if there's a way to query clojure's keyword pool?
10:41	rvsv	1.11.4
10:41	CookedGryphon	I want to make a test.check generator which before it starts generating random keywords, tries out all the keywords which it knows have popped up somewhere else in the program, and so is more likely to quickly hit special cases/naming conflicts etc.
10:43	justin_smith	rvsv: this is a bug in that version - easy to see if you read the code https://github.com/drewr/postal/blob/1.11/src/postal/sendmail.clj#L68
10:43	justin_smith	that arity of the function calls itself
10:43	justin_smith	and of course that would stack overflow on that line (the line in your error), line 68
10:44	justin_smith	rvsv: if you update to a newer version, that error is fixed
10:44	rvsv	Right, thanks!
10:44	justin_smith	also, that is a hilariour bug
10:44	justin_smith	IMHO
10:45	justin_smith	(not that I haven't done worse myself)
10:45	reiddraper	CookedGryphon: neat idea
10:45	justin_smith	rvsv: that's why it was in UnixFile - on each iteration it tries to find a sendmail program as a file, then it recurs and tries to find one again
10:46	rvsv	Which of course will blow up.
10:46	justin_smith	right
10:46	rvsv	Ah, you're a lifesaver, I was pulling my hair out
10:46	CookedGryphon	reiddraper: so looking at it, the map is private and I can't see a way to get it out, but I think it's possible to construct without interning, so you wouldn't pollute the pool with randomly generated ones for subsequent runs
10:46	rvsv	I'll be more careful about just updating to whatever lein ancient says is new, and test each one.
10:46	justin_smith	rvsv: well, how many times does it have to say "line 68" before you look at what's on line 68 :D
10:47	rvsv	I know - Before I just scrolled down but when I had to copy it I was like, "hey, this goes on for a really long time". Huh.
11:07	justin_smith	my coworkers would rather take my cljc files and split them into separate clj and cljs files than try to upgrade to a newer cider that supports cljc :P
11:09	TEttinger	my coworkers would possibly object to my lack of shoes, if I had any coworkers
11:09	justin_smith	they also go around barefoot all the time
11:10	justin_smith	do you use cider while being afraid to update it? maybe you guys would get along great
11:56	RedNifre	Good day everyone.
11:57	RedNifre	Started clojure yesterday and got something working with protocols, records and macros, but my second try fails at line 1 and I don't understand why: https://gist.github.com/RedNifre/d563cc6629c515186f86
11:58	RedNifre	Is it possible to use records without protocols?
12:03	justin_smith	RedNifre: if you don't need protocols, there's not much point to using records
12:03	justin_smith	but yeah, sure, go for it
12:03	RedNifre	oh? what do you mean?
12:03	RedNifre	I thought a protocol was like an interface/abstract class and a record is like an object?
12:03	justin_smith	RedNifre: they have only slim advantages if you are not using protocols
12:04	justin_smith	and the overhead of defining them is usually not going to be worth that advantage
12:04	RedNifre	But what's the alternative? raw maps?
12:04	justin_smith	A record is not like an Object, it's like a Class
12:04	justin_smith	yes, the alternative is just using a hash-map
12:04	justin_smith	RedNifre: and that's what we use instead of records 99% of the time
12:05	RedNifre	ah, right, I meant class. So that I can do (Room. "kitchen" "food" []) like in my example...
12:05	justin_smith	unless we need a feature like protocols
12:05	RedNifre	okay, I'll see if I can rewrite it. Still, what's wrong with my code?
12:05	justin_smith	RedNifre: you can't implement methods that are not part of some protocol
12:06	justin_smith	RedNifre: in clojure a method is always from some protocol or interface, you can't just invent them from scratch
12:06	RedNifre	So... every "class" needs to implement an "interface"?
12:06	justin_smith	no!
12:06	justin_smith	you don't need to implement methods
12:07	justin_smith	in fact we quite like dumb classes that don't have methods other than accessors
12:07	justin_smith	and you can implement as many protocols or interfaces as you like, 0 or more
12:08	RedNifre	So protocols only make sense if you have multiple records conforming to it... which means in my case the record is a bad choice because the Room would be the only thing to conform to the protocol?
12:08	justin_smith	RedNifre: also, on line 7, "keyword" is a noop, it might as well not be there because it does nothing
12:09	justin_smith	RedNifre: no, it makes perfect sense to have a protocol only implemented by one record
12:09	justin_smith	but really it might be easier to use a hash-map plus a function
12:09	RedNifre	In line seven, the idea was to have a macro for set entries. The idea is that "stuffs" should contain the same things as "world"
12:09	justin_smith	RedNifre: what does "keyword" supposedly do?
12:10	justin_smith	because right now it might as well be a comment
12:10	RedNifre	It turns line 10 into what you see in line 15... at least that's the idea.
12:10	justin_smith	it's not capable of doing that
12:10	RedNifre	I guess the problem is that one macro can not turn into two separate things?
12:11	justin_smith	RedNifre: a macro must return the thing that gets compiled
12:11	justin_smith	RedNifre: if it's not the last thing in the body of hte macro, it's not returned, so it's a noop
12:11	justin_smith	RedNifre: we have the do form, so you can emit (list 'do keyword ...)
12:12	RedNifre	So you can't have a macro m that turns (m "ha") into :ha "ha" and use it in a set like {(m "ha")} to compile it as {:ha "ha"}?
12:12	justin_smith	and that way "keyword" gets compiled in the output
12:12	justin_smith	RedNifre: not without some splicing or concatenation
12:12	justin_smith	RedNifre: clojure expressions can only return one value, there is no clojure semantics for returning two values
12:13	justin_smith	except as separate items in some collection
12:14	craftybones	You won't be able to compile it as {:ha "ha"}. Maybe as {{:ha "ha"}}
12:14	justin_smith	craftybones: he can with concatenation or splicing, eg. ~@
12:14	craftybones	(m "ha") -> {:ha "ha"}
12:14	craftybones	{(m "ha"} -> {{:ha "ha"}}
12:15	craftybones	sorry {(m "ha")} -> {{:ha "ha"}}
12:15	justin_smith	`{~@[ha "ha"] ~@nil}
12:15	justin_smith	,`{~@[ha "ha"] ~@nil}
12:15	clojurebot	#error {\n :cause "Unable to resolve symbol: ha in this context"\n :via\n [{:type clojure.lang.Compiler$CompilerException\n :message "java.lang.RuntimeException: Unable to resolve symbol: ha in this context, compiling:(NO_SOURCE_PATH:0:0)"\n :at [clojure.lang.Compiler analyze "Compiler.java" 6704]}\n {:type java.lang.RuntimeException\n :message "Unable to resolve symbol: ha in this context"...
12:15	justin_smith	,`{~@['ha "ha"] ~@nil}
12:15	clojurebot	{ha "ha"}
12:15	RedNifre	Well, conflating the hash key with the human readable name is a bad idea anyways.
12:16	justin_smith	the ~@nil is there for sad reader-related reasons
12:16	RedNifre	I don't understand anything in that line.
12:16	craftybones	@justin_smith this will evaluate over the containing set?
12:17	justin_smith	RedNifre: on line 9, you create a hash map where the key is a kitchen and the value is a corridor?
12:18	justin_smith	oh never mind, that goes back to the previous misunderstanding
12:18	justin_smith	,(conj {} [:ha "ha"]) ; RedNifre this is simpler and accomplishes the same thing
12:18	clojurebot	{:ha "ha"}
12:19	justin_smith	RedNifre: so your macro can return a vector of two items, and stuffs can call conj
12:24	RedNifre	I took your advice and tried it without records. I have three approaches, can you give me some feedback?: https://gist.github.com/RedNifre/4a18f1d6095a0d19369d
12:24	justin_smith	RedNifre: except for the bracket placement that looks reasonable, - though you'd want to use defn not def for room-name, room-look, room-inventory
12:24	RedNifre	oh, right.
12:24	RedNifre	which approach of the three looks reasonable?
12:24	RedNifre	Is one of them most idiomatic or is it just personal taste?
12:24	justin_smith	the second is what you would usually see with clojure code
12:25	justin_smith	if I understand what the three options are correctly...
12:25	justin_smith	second one being the thing starting on line 14, anding on line 24
12:26	RedNifre	The first one is an explicit map, the second one builds the same map with a helper function and the last one is a list where it is informal which thing in the list means what.
12:31	RedNifre	Yeah, with better formatting it looks fine, all without objects. By the way, is there something like gofmt to format the code automatically? I'm currently doing freestyle formatting... https://gist.github.com/RedNifre/c9bd8647827caf33a52a
12:33	xemdetia	RedNifre, I usually use emacs formatting, you should see if there is a good editing mode for whatever you are using
12:33	xemdetia	I don't know of any third party ones
12:33	xemdetia	err
12:33	xemdetia	external tool ones
12:35	RedNifre	So I finished the clojure part of "seven languages in seven weeks" but it was very brief. Can you recommend a good tutorial/book to learn clojure? I found several books but I can't tell which one might be best.
12:42	wasamasa	living clojure
12:55	hlolli	Can you test for a persitent vector if it has subvectors (subvec? [[ ] [ ] ] ) ;=> true (subvec? [ ]) ;=> false ???
12:59	hlolli	Well I'll just do (if (vector? (get nth 0)) (blabla))....
13:00	luma	,(some vector? [[] []])
13:00	clojurebot	true
13:00	luma	,(some vector? [])
13:00	clojurebot	nil
13:00	hlolli	nice! thanks!!
13:03	RedNifre	why is it println and read-line instead of print-line or readln?
13:05	RedNifre	If I want to create a tiny interactive program, do I use loop + recur to communicate with the user through read-line and println? Or what's the best practice here?
13:28	justin_smith	RedNifre: that works as long as you are not running a repl
13:29	RedNifre	What are you implying? That I should do it differently so that I can debug my program in a REPL?
13:29	RedNifre	Or should I just put a debug command in the loop that stops it so I can continue in the REPL?
13:29	justin_smith	RedNifre: I'm saying that the REPL also wants to read-lines and print and it gets messy
13:30	justin_smith	but if you are directly running the interactive code, with no repl, it will work just fine
13:31	justin_smith	you might want to separate the reading of a line from in from the "parsing" you do, in order to test things more easily in a repl
13:31	justin_smith	or via unit tests even
13:32	RedNifre	I see.
13:33	RedNifre	I wanted to print a little prompt with (print ">") right befor the (recur read-line) statement, but the ">" only shows up after I input something. Why is that?
13:33	justin_smith	that could be as easy as writing the "parse" function to take an optional input stream (defaulting to in) or an alternate source of strings (defaulting to a function that calls read-lin on in)
13:33	justin_smith	RedNifre: you need to call (flush) unless the output ends with a newline
13:33	RedNifre	ah
13:36	xemdetia	wasamasa, that's the first reference I saw to living clojure
13:36	xemdetia	is it good?
13:36	wasamasa	xemdetia: yup
13:36	wasamasa	xemdetia: got a copy here for a colleague
13:37	wasamasa	xemdetia: it's nice for beginners and is using idiomatic code
13:37	xemdetia	cool, looks like amazon gets more money today
13:37	xemdetia	(or whoever I end up buying it from)
13:39	wasamasa	this is sort of a preview: https://www.howistart.org/posts/clojure/1
13:39	wasamasa	since it's the same author
13:40	wasamasa	the overall style is comparable
13:42	xemdetia	yeah I found a sample on oreilly's site
13:42	xemdetia	the chapter layout looks good
13:43	wasamasa	if you want something more advanced, hm
13:44	wasamasa	the joy of clojure
13:44	wasamasa	but the second edition
13:46	xemdetia	wasamasa, yes I had heard of that one and that's been on my to-buy list
13:46	wasamasa	the book describes itself as "Drinking from the fire hose"
13:46	wasamasa	I found it too much for someone new to the language
13:47	wasamasa	but maybe you are into that kind of thing :D
13:47	xemdetia	that's what I have heard described here which is fine
13:47	xemdetia	no I just like technical books among clojure
13:47	xemdetia	so if there is a better replacement for the 'beginner clojure' book that's interesting
13:48	xemdetia	replacement is the wrong word
13:48	xemdetia	alternative is what I should have said
13:51	RedNifre	regarding the REPL, when I load a file with clojure -i myscript.clj -r, the history in the REPL gets broken, when I hit the up arrow I just get ^A or something. Why is that? What's the right way to load or reload a script in the REPL?
13:51	justin_smith	RedNifre: clojure itself does not supply readline support
13:52	justin_smith	RedNifre: lein repl does supply readline, you can also use rlwrap to provide readline facilities to any program (including a clojure repl)
13:53	justin_smith	RedNifre: to reload a namespace use (require 'some.ns :reload) or (require 'some.ns :reload-all)
13:53	justin_smith	the latter will recursively load the namespaces that ns loads as well
13:53	justin_smith	(recursively reload that is)
13:53	RedNifre	not sure I understand. Are you saying that it's impossible to load a script into the REPL without losing the up-arrow history function?
13:53	justin_smith	RedNifre: no, I am saying the proper way to load a script is with require
13:54	RedNifre	so in order to load my.clj I need to read about namespaces first, huh? :)
13:54	wasamasa	that would be a good idea
13:54	justin_smith	RedNifre: or you can use load-file like a neanderthal, that simply unconditionally loads a file
13:54	justin_smith	but you won't get far in clojure without dealing with namespaces
13:55	wasamasa	neanderthals use clojure?
13:55	justin_smith	wasamasa: yes, and they use load-file instead of require, try to keep up
13:55	justin_smith	:P
13:55	RedNifre	sounds good, since I started clojure yesterday I'll do the neanderthal way today and read about namespaces tomorrow.
13:57	justin_smith	RedNifre: the thing is, using load-file never really comes up in normal code, and we use require and ns everywhere. But learn at your own pace I guess.
14:00	RedNifre	Is there a difference between a fn that takes no parameters and a quoted piece of code?
14:00	justin_smith	yes
14:01	justin_smith	one of them has been compiled, the other cannot run unless you compile it
14:02	justin_smith	RedNifre: clojure has no interpreter, you can only run things that have been turned into byte code
14:02	justin_smith	this is done by the E (eval) in the REPL
14:03	RedNifre	I'm surprised, I thought "data as code" was a big thing in the Lisp world. So that doesn't work in Clojure?
14:04	justin_smith	RedNifre: it does, data becomes code when you compile it with eval
14:04	justin_smith	I'
14:04	justin_smith	m saying that it isn't something you can run before that eval step, which is the difference between a quoted list and a function
14:05	justin_smith	,'(+ 1 1)
14:05	clojurebot	(+ 1 1)
14:05	justin_smith	,(eval '(+ 1 1))
14:05	clojurebot	2
14:05	justin_smith	in normal code, eval is a sign you are a) doing something exceedingly clever or b) making a huge mistake. Often both at once!
14:06	RedNifre	Right... so if I have either a map of Strings to fn or String to quoted code and when the user enters a command that is found in the keys of the map I want to run the code... I should use fn as values because eval is only needed when you truly write new code at runtime?
14:07	RedNifre	So the rule of thumb is "only use quoted code if there is no other way"?
14:07	justin_smith	RedNifre: yes, if possible have functions you can run on the user input / look up in a hash map based on user input
14:07	justin_smith	if you want the full power of clojure to compile code at runtime, you need to use eval on user input
14:08	RedNifre	no, I would never eval user input.
14:08	justin_smith	(well, you need read / read-string first to make compilable tokens, followed by eval, but that's the basic idea)
14:08	RedNifre	What I have now is { "help" '(println "Type 'quit' to quit.")} but {"help" (fn [] (println "type..."))} would work just as well.
14:08	justin_smith	yeah, if you aren't compiling input from the user, you should probably be using a proper function which is compiled before the user interaction starts
14:08	RedNifre	no no no, I don't want the users to enter code.
14:09	justin_smith	right
14:09	justin_smith	so yeah, hash map where values are functions sounds perfect
14:09	justin_smith	they could even optionally take args for more flexibility
14:09	RedNifre	so it's fully compiled to bytecode, right? No data of the code is left at runtime at all? No reflection?
14:10	justin_smith	RedNifre: and, in fact, a fn will work better than eval, because then you don't have the resource overhead of running the compiler at runtime either
14:10	justin_smith	RedNifre: there is potentially reflection
14:10	justin_smith	it's bytecode that reflects (sometimes) on its args
14:11	justin_smith	RedNifre: we have a flag you can turn on for "warn on reflection", which gets triggered when the code for runtime reflection gets compiled
14:11	justin_smith	it's very useful for finding slow code
14:16	RedNifre	Is there a short form for (fn [] ...) ?
14:16	justin_smith	#()
14:17	justin_smith	the first arg is % or %1, second arg is %2, all remaining args after last accessed are %& (one list)
14:17	justin_smith	,(#(+ % %3) 1 'a 2)
14:17	clojurebot	3
14:22	RedNifre	Ah, great. But how do I call it? (apply bla) doesn't work and (apply bla []) is clumsy.
14:22	justin_smith	RedNifre: you don't need apply
14:22	justin_smith	just wrap it in parens
14:22	justin_smith	,(#(print 'OK))
14:22	clojurebot	OK
14:23	RedNifre	oh, right! How could I forget that...
14:23	justin_smith	RedNifre: which leads us to another gotcha: only wrap things in parens when they are functions you want to call
14:24	justin_smith	(or macros or special forms etc. of course)
14:24	RedNifre	hm, in what situations might I accidentally put something into parens that I would not want to call?
14:24	justin_smith	RedNifre: I see it from newcomers all the time
14:24	justin_smith	(if true (1) (2))
14:25	justin_smith	it would work in another language, it errors in clojure, for obvious reasons
14:25	justin_smith	or (if (true) 1 2) - just as bad
14:26	ystael	justin_smith: obviously all non-function values should automatically convert to constant functions when invoked
14:26	justin_smith	ystael: I've often thought that 2 should be the function that calls its arg twice
14:26	ystael	ooh, that's way better
14:27	celwell	Hi, what is the best way to assoc key-value pair (kv) into map (m) iff v is non-nil?
14:28	justin_smith	,(let [m {} kv [:a 0]] (or (and (val kv) (conj m kv)) m))
14:28	clojurebot	{:a 0}
14:28	justin_smith	that's how I'd do it at least
14:28	celwell	is a let really necessary, that seems wy too messy
14:28	justin_smith	celwell: let was in order to have the names you proposed
14:29	celwell	oh i see, sorry jumped th gun
14:29	justin_smith	,(or (and (val [:a 0]) (conj {} [:a 0])) {})
14:29	clojurebot	{:a 0}
14:29	justin_smith	there's repetition of the literals when you don't have bindings, of course
14:30	RedNifre	Hm, in one case in my map I just have a String and it currently looks like { "special" #(str "not implemented")}. Is there an overhead involved in using str to just return the str? for some reason #("this") doesn't work when I retrieve it with ((get commands "special")) even though it would make sense to me if #("hm") was a function that returned the string. But since the syntax highlighting is messed up for #("hm") I guess that's not al
14:30	RedNifre	lowed?
14:30	ystael	justin_smith: note that celwell asked for "iff v is non-nil", not "iff v is truthy"
14:30	justin_smith	,'#("hi"0) ; see the expansion, this is why it doesn't work
14:30	clojurebot	(fn* [] ("hi" 0))
14:30	justin_smith	ystael: true
14:31	justin_smith	ystael: (some (val kv)) of course
14:31	RedNifre	So is there something like #("hi") that expands to (fn [] "hi")
14:31	justin_smith	err
14:31	celwell	I wonder if this would be a good candidate for a macro, like: assoc-if-non-nil
14:31	justin_smith	(constantly "hi")
14:31	ystael	celwell: function, no need for a macro here
14:32	RedNifre	Ah, great.
14:32	oddcully	,(let [m {:a 1} k :b v nil] (into m (when-not (nil? v) [[k v]])))
14:32	clojurebot	{:a 1}
14:32	oddcully	ey! da bot is back
14:33	justin_smith	oddcully: if you used conj instead of into you could avoid creating a useless vector
14:34	oddcully	that's totally true
14:35	justin_smith	oddcully: but you avoided my silly or / and, which is great
14:35	justin_smith	I forgot that (conj m nil) is just m :)
14:35	celwell	justin_smith: yeah given that it just ignores nils I'm going to go with conj here, thanks
14:35	oddcully	but i bet there is something better than (when-not (nil?))
14:36	gfredericks	,(doc some?)
14:36	clojurebot	"([x]); Returns true if x is not nil, false otherwise."
14:36	celwell	well I'm just using (when x [:a 1])
14:36	oddcully	(when (some?))
14:36	celwell	truthy is fine for me here
14:36	oddcully	gfredericks: yeah just tried that
14:45	hlolli	Is there any alternative to reset! function for agents? Or other function that updates all keys that match?
14:49	RedNifre	I'm trying to select a random key from a map. This works but is kinda clumsy, how can I improve it?: (->> world (keys) (count) (rand-int) ((vec (keys world))) )
14:50	RedNifre	I'm converting to vector in the end because accessing an element in a sequence with (someSequence 3) seems to not work.
14:50	justin_smith	RedNifre: (key (rand-nth (seq m)))
14:50	justin_smith	RedNifre: (v 3) only works with vectors, not other sequence types
14:50	RedNifre	I see, thanks.
14:51	justin_smith	or (rand-nth (keys m)) actually
14:51	justin_smith	,(rand-nth (keys {:a 0 :b 1 :c 2}))
14:51	clojurebot	:b
14:52	hlolli`	justin, did you see if you or anyone replied my question above, because my internet broke appearantly and cant see last 10 minutes
14:52	justin_smith	hlolli`: no, but reset! doesn't work on agents of course
14:52	justin_smith	and I don't know what you mean by "updates keys that match"
14:54	hlolli`	so I have {:a 0 :b 0} map in one agent and {:a 1 :b 1} map in other, and on some point I want all keys to be updated to the other map. And there are many keys that will take a long time to type manually (assoc map :val1 (:val1 @agent)) etc...
14:55	justin_smith	hlolli`: so you want something like (send map merge agent) ?
14:55	justin_smith	,(def a (agent {}))
14:55	clojurebot	#'sandbox/a
14:55	justin_smith	,(send a merge {:a 0 :b 1 :c 2 :d 3})
14:55	clojurebot	#object[clojure.lang.Agent 0x796e5ca2 {:status :ready, :val {}}]
14:55	justin_smith	,@a
14:55	clojurebot	{}
14:55	justin_smith	,@a
14:55	clojurebot	{}
14:55	justin_smith	I seem to have done this wrong!
14:56	justin_smith	,(send a #(merge % {:a 0 :b 1 :c 2 :d 3}))
14:56	clojurebot	#object[clojure.lang.Agent 0x796e5ca2 {:status :ready, :val {}}]
14:56	justin_smith	,@a
14:56	clojurebot	{}
14:56	hlolli`	hmm maybe.. let me check
14:56	hlolli`	this worked for me, seemingly. I think this is excacly what I needed.
14:56	justin_smith	yeah, I think agents may be funky in clojurebot
14:57	justin_smith	so yeah, send a merge, no need for the #() funkiness
14:57	hlolli`	yes, thanks a million, I still notice that atoms tend to be slower and more unreliable than agents in fast triggering system Im creating.
14:57	justin_smith	hlolli`: makes sense - iirc you change the data frequently, and agents queue up while atoms retry
14:58	justin_smith	so atoms get slower faster when you have frequent update
14:58	justin_smith	and are optimal for rare updates (thanks to their optimism)
14:59	justin_smith	"get slower faster" - me english good!
14:59	hlolli`	Im creating a note sequence index, and on some new bars, I need to reset the counter in one do loop same time I evaluate a sound. Only on the first beat (modulo 0) the atoms cant update the index fast enough.
14:59	justin_smith	atoms perform well for rare updates, and slow down with more heavy usage
14:59	justin_smith	hlolli`: makes sense, yeah
15:00	justin_smith	hlolli`: if you wanted to try functional programming you could make a "measure status" data structure, and make your measure rendering function return a brand new measure status
15:00	justin_smith	but imperative is an easy fit for something like this too
15:01	hlolli`	hmmm... yes I'd like to be more functional, my code is a mix of functional style and imperative style.
15:02	hlolli`	how are you thinking about measure status? Where are you going to store the "status" if not in a atom/agent/ref?
15:02	justin_smith	hlolli`: you could write a function that takes a "state" and returns a "new state" and a measure of music data
15:03	justin_smith	hlolli`: you would put all the data that you are currently putting in atoms, agents, and/or refs, and put them in immutable data in "state"
15:03	justin_smith	and just make a new one each time
15:03	justin_smith	your "driver" function (which could be the renderer itself!) would take a state, feed it to the renderer, and get back a measure of music and a new state
15:03	sameerynho	hey folks, is there any websocket lib around for clojure ?
15:04	justin_smith	sameerynho: I have had great luck with sente
15:04	justin_smith	(if you have cljs on the client side)
15:04	sameerynho	justin_smith: i don't have cljs
15:04	hlolli`	ok, yes I see now, was not really getting my head around this first.
15:04	justin_smith	sameerynho: then in that case standard websocket usage as provided by aleph or http-kit should be fine
15:05	justin_smith	hlolli`: the only real difference is that your "state of the music" is all in one data structure, and instead of changing it you return a new one. It seems weird, but it's easy after you do it a couple of times, and it has some interesting advantages
15:06	sameerynho	justin_smith: thanks man
15:06	justin_smith	and you can do this fractally - if you have a melody generator it could take an initial "state of the note", and generate a next note and a new "state of the note"
15:07	justin_smith	hlolli`: and since this is csound you could do this all the way down to the granular texture level :)
15:08	hlolli`	yes yes, I see. I will defenitely be thinking about this next days. These state functions would have to know about what I want for the future. For example when do I want to restart the note pattern, how long the note pattern is etc.
15:09	hlolli`	State "quote on quote". I need to think this more functional for sure.
15:11	justin_smith	hlolli`: right, it's named state but technically is immutable - the general idea though is that all the data you would need to track (the counter that lets you know when to restart, how long the pattern is, etc.) can all be carried in an immutable object, and you can make new ones as needed (and they will share structure with old ones as applicable because clojure's immutable values are nifty like that)
15:14	RedNifre	Well, day 2 of Clojure is coming to an end: I wrote a tiny text adventure in which you can look around and teleport to other places, if anyonen would like to give me feedback on the code style etc. I'd much appreciate it: https://gist.github.com/RedNifre/53bad0f35b24725de65a
15:14	RedNifre	It's most likely not a viable base for a "real" game, the point of this is just to understand some Clojure concepts...
15:15	hlolli`	yes, this is on my todo-list for my programming.
15:15	hlolli`	Well, where's the line of hacking and programming? Don't want to sound too snobby :)
15:16	justin_smith	RedNifre: similarly to what I was mentioning to hlolli`, you could introduce player interaction with the world by making the list of exisitng objects an argument to recur (and optionally making new ones / getting rid of some at the recur point)
15:16	justin_smith	heh
15:17	RedNifre	Yeah, that's planned for next time.
15:18	RedNifre	I also want the player to be able to pick things up or move from room to room (currently, the teleportation is basically fake, the player doesn't enter the inventory of the target room). Figuring out how to do all this in an immutable fashon will be tricky I guess.
15:18	justin_smith	RedNifre: I used to be a mud admin, so this brings back fun memories. You could even have a command that builds a new room or passage and inserts it into the world at the recur point
15:18	justin_smith	RedNifre: allowing interactive building while exploring in-game
15:18	RedNifre	That's what I also thought about :)
15:18	justin_smith	RedNifre: not tricky at all, I just told you how to do it - make all rooms and objects be arguments to recur
15:19	RedNifre	And it could be linked to an IRC channel or be accessible via XMPP.
15:19	justin_smith	cool, yeah
15:20	RedNifre	yes, but I meant what if I had a function (defn move [world player target] ...) could I compute the new world in one step or would I first have to move the player to the new room creating a world where he is in two places at once and then create another world where he is no longer in the first room?
15:20	RedNifre	Well, if Clojure is good at basing new copies on old ones it doesn't matter, right?
15:21	justin_smith	RedNifre: you want ticks in that kind of game. Things change when ticks happen. The recur is the tick.
15:21	justin_smith	right, all you need to do is let the data you don't need fall out of scope
15:21	sameerynho	guys, I need to create a websocket server for about 30M people, I stock between Clojure and Go? I'm new to both. Can someone help me to choose one ?
15:22	xemdetia	sameerynho, if you have 30M people problems what is your existing infrastructure based on
15:22	RedNifre	I'm new to Clojure and only had a brief look at Go. Go seems easy to pick up and scales, but it is a low level language so I'm afraid that I'll code myself into a corner with it...
15:23	sameerynho	xemdetia: it's a new feature, we already have a rails application
15:23	RedNifre	You might like Elixir, it's Erlang with Ruby syntax.
15:24	RedNifre	...but I guess it depends on the skill set of your team... or are you the only one working on it?
15:24	RedNifre	Which languages do you know already?
15:25	sameerynho	RedNifre: yupe I find that interesting, but the thing is I need to choose the lang wisely for example one of clojure pros is the existance of Immutant and ability to run on JVM
15:25	RedNifre	Who will maintain it?
15:25	sameerynho	RedNifre: I'm alone, Ruby, python, php, C/C++, lisp perl .....
15:26	RedNifre	so what's your opinion on lisp VS ruby/python/C++?
15:26	xemdetia	sameerynho, if it's on your own it sounds like you should prototype both and then evaluate which one seems easier to bring to production
15:26	sameerynho	RedNifre: I like lisp, and also i love Ruby
15:27	xemdetia	I feel go and clojure (or java interop) could probably give you the same power
15:27	RedNifre	Well, Go has nearly no freedom, so it might feel very different from Ruby.
15:27	sameerynho	xemdetia: that's a good point
15:27	augustl	is the problem shardable?
15:27	sameerynho	RedNifre: what do you mean ?
15:27	xemdetia	I think he's just saying go isn't dynamically typed
15:27	xemdetia	and compiled
15:28	RedNifre	In Ruby, you are allowed to do basically everything, including rewriting the standard library at runtime.
15:28	xemdetia	but it also has a more strict project/build structure
15:28	xemdetia	but that's not awful if you are also considering java
15:28	RedNifre	In go you are not even allowed to use tuples because they are too tricky, it forces you to destructure tuple return types right on the spot.
15:28	augustl	"In ruby, you don't ask where the bathroom is, you just redefine it to be wherever you are and then shit all over everything." :)
15:28	RedNifre	:)
15:29	RedNifre	I'm also not sure how Go's "strict typing but without generics except for in the standard library" works in practice. I make excessive use of generics in statically typed languages so I have a hard time imagining how Go would work for me.
15:30	augustl	I have a very visual relationship with that quote. I can see it before my eyes!
15:30	RedNifre	On the other hand, the standard structures in Go are indeed generic so if you stick with Clojures philosophy of avoiding objects in favour of standard structures Go might not be that bad...
15:30	RedNifre	But if you like Lisp, Clojure is probably a good idea? Not sure.
15:30	augustl	exceptions is a killer feature for me
15:31	xemdetia	I still think his main question is an infrastructure one, if he already has a legacy codebase whatever gels best seems to be the easiest
15:31	oddcully	augustl: in that metaphor perl is a doggy bag. you use it once for something and then throw it away
15:31	augustl	I like to just fail miserably with a loud boom, instead of trying to handle every failure case
15:31	augustl	oddcully: haha, nice
15:32	RedNifre	What's your view on using Clojure for small command line scripts?
15:32	sameerynho	Generally I need to know technical advantages of Clojure over Go
15:32	augustl	if I were to do that I'd probably see if I could use nodejs instead of the jvm
15:33	sameerynho	RedNifre: I rather to use ruby with Thor instead of node or jvm
15:33	oddcully	RedNifre: use /bin/sh
15:33	RedNifre	I'm currently working on some nodejs stuff and I can not recommend it at all... or do you mean clojurescript on top of nodejs?
15:33	justin_smith	sameerynho: clojure has more flexible polymorphism that isn't as clumsy to use, and extensive usage of real threads. Also immutable data structures can save a lot of sanity (while costing a lot of RAM)
15:33	RedNifre	oddcully nah, I only use /bin/sh for very tiny things. For medium things I currently use Ruby, but Clojure might be cleaner, not sure.
15:34	justin_smith	people complain about the startup time, but when you take nrepl and lein out of the equation it's not so terrible
15:34	augustl	sameerynho: seems to me that if you need a lot of throughput on the JVM you should probably write it in Java due to the large corpus of knowledge on how to write Java code that makes the JVM behave
15:34	oddcully	RedNifre: the point here is, that even java -cp clojure.jar might not be worth the overhead
15:34	augustl	sameerynho: I have no experience with high scalability myself though..
15:34	sameerynho	justin_smith: Go uses the immutable data structures too , so they both share the "too much ram" problem
15:35	RedNifre	The thing is that I currently use Haskell for big things and the thought of using a dynamically typed language like Clojure as a replacement is not something I'm comfortable with just yet (but, hey, it's my second day of Clojure, who knows what I'll think tomorrow?)
15:35	justin_smith	sameerynho: it's a difference of degree - go offers data structures that are mutable as defaults too
15:35	xemdetia	For me command line scripts are designed to be subshell'd and java is just not what you want to use for a find -exec over a lot of stuff
15:36	justin_smith	RedNifre: don't rule out trying OCaml as a less demanding Haskell too
15:36	sameerynho	thanks guys
15:36	RedNifre	...or Idris as a more demanding Haskell ;)
15:36	justin_smith	haha
15:37	oddcully	well tbh ruby (which i never did) or python are quite good for this stuff
15:37	RedNifre	Yeah, I haven't checked out OCaml yet, it's on my list...
15:37	justin_smith	well, you were talking about something dynamically typed, and though OCaml is still strongly typed, it's more friendly to our web-footed friends
15:38	augustl	I need to learn some type theory so I can shake the feeling "those folks know something I don't"
15:38	RedNifre	I only had a superficial look at Erlang, but THAT language sounds fantastic in theory: perfectly robust with the feature to swap code without downtime, you declare reboot policies for crashes etc...
15:38	justin_smith	RedNifre: as long as you don't need high performance, yeah
15:39	RedNifre	Really? I thought Erlang scales... easy to spread across many machines etc... not sure though.
15:39	oddcully	now it's out
15:39	justin_smith	RedNifre: oh, now we have to define performance, "as long as you don't need low latency and high throughput, it is great"
15:39	oddcully	may the bots kick me out of this chanel
15:39	justin_smith	haha
15:40	RedNifre	I never saw Groovy outside of Gradle... didn't the inventor say that if he had known about Scala earlier he wouldn't have invented Groovy because Scala is better in every way?
15:40	snowell	I've loved what I've used of Groovy/Grails
15:40	justin_smith	RedNifre: scala comprises 5 languages better than groovy, 5 that are worse, and 5 that nobody has discovered yet
15:40	snowell	If that scala quote is true…that's pretty hilarious
15:40	oddcully	groovy is the java minus ide-generated-bs
15:41	snowell	And plus some nice syntactic sugar
15:41	xemdetia	well I believe it, I mean I was messing around a ton trying to get ECL to work before I really dived into clojure properly
15:41	RedNifre	I use Kotlin for java minus ide-generated-bs :)
15:41	augustl	I think it's more balanced than that, it's not that Scala is better in every way according to the creator, but Scala would have been good enough so he wouldn't have bothered
15:41	snowell	I mean, how many languages do you know with an operator called the spaceship operator? :D
15:42	ystael	snowell: originates with Perl, I believe?
15:42	RedNifre	Oh, that one exists outside of Ruby? :D
15:42	oddcully	ystael: perl... we had earlier ;p
15:42	augustl	snowell: and s/map/collect as well as s/reduce/inject
15:42	snowell	Okay, fine, I never said groovy was the ONLY one
15:42	augustl	that's a spaceship thing apparently
15:42	snowell	grumble grumble
15:43	xemdetia	I spend most of my time writing perl right now actually
15:43	xemdetia	works on anything
15:43	oddcully	augustl: once you get the juniors out of the state of using each for _everything_ its even ok with the java folks
15:43	augustl	:D
15:44	augustl	current day job is spent writing a groovy project built with gradle that depends on clojure 1.7 for the data structures ;)
15:45	RedNifre	I have to admit that I'm actually coding in Java... yeah, there aren't much options for Android... but the new Kotlin release shouldn't be too far off...
15:46	RedNifre	That reminds me: I heard some rumors about Clojure on Android being the next focus of the Clojure project after ClojureScript is mature, is that true?
15:46	RedNifre	...not that I could possible introduce Clojure at the office, but at least I could use Clojure for private projects.
15:47	xemdetia	wasn't there a talk about someone who pulled that off like 2 or 3 years ago
15:47	justin_smith	RedNifre: there are at least a couple of ways of using clojure on android, but I don't know if it will ever be even as high a project for the core cognitect clojure team as cljs is
15:47	justin_smith	I mean we still have a vestigal clojure-CLR too
15:47	RedNifre	Yeah, but that doesn't count... I mean, you can even write Android apps in Haskell but not really... as long as it's not connected to the standard API in a useful way it's a non-starter.
15:48	justin_smith	RedNifre: well both versions I know of (using the android vm and using cljs) will tie into the core android functionality just fine...
15:48	RedNifre	How well does Clojure mix with Java in practice? Could you put your main business logic in a Clojure jar and use that one in your Java Android app?
15:48	justin_smith	clojure has and will always prioritize direct access to host functionality
15:49	justin_smith	RedNifre: calling clojure from java, and java from clojure, are both very very easy
15:49	justin_smith	as in, you could probably fool someone into thinking no language barrier was being crossed, as long as they didn't look at the source
15:50	oddcully	RedNifre: that quote of the author of groovy have to be taken into persepctive: why would he do kotlin now if scala was _so_ awesome?
15:51	RedNifre	In that case I guess having a Clojure jar that can access both Android's SQLite database and the network would be enough to make me happy. GUI on Android is very special, there exist a ton of Java libraries to make GUI easier, so having the GUI stuff in Java but handle everything else in Clojure sounds appealing to me.
15:51	RedNifre	oddcully what, Kotlin is done by the same guy as Groovy? Didn't know that.
15:52	RedNifre	I just heard that rumor from somewhere, not sure if it's true.
15:52	oddcully	RedNifre: he now works for jet"brains"
15:52	justin_smith	RedNifre: yeah, I think the big hurdles are the extra RAM usage and startup time - but if you can accomodate those, bob's your uncle (and there are some long term plans for those... we'll see)
15:52	RedNifre	And I didn't say that Scala is great, only that it might be better than Groovy according to rumors, not sure ;)
15:52	oddcully	RedNifre: also this quote is taken out of context
15:52	RedNifre	But yeah, the point of Kotlin is to have a better Java without having the complexity of Scala.
15:53	RedNifre	For example, in Scala implicits change everything everywhere while in Kotlin you have to explicitely import them one by one to make them available in your source file.
15:53	oddcully	RedNifre: also this quote has been produces way back. groovy nowadays is static typed if you like etc
15:53	RedNifre	Do you have the quote handy? I only heard rumors.
15:57	oddcully	RedNifre: ask the duck for strachan kotlin
15:57	oddcully	or google if you have to
16:14	hlolli	justin_smith where would you recommend me to look/read for making an functional/recursive state counter
16:15	hlolli	I changed the atom to agents and I have now even more problems, I know the way you suggested for indexes would not include these problems Im havinf
16:30	RedNifre	I think I heard something about variables only existing on the top level while all datastructures are truly immutable. Is that true or could I stick atoms / refs anywhere I want?
16:33	RedNifre	Are there annotations? Are there user defined annotations? Do they support unicode? Could I create a "deprecated" annotation that instead of using the word "deprecated" uses the unicode character for spiderweb instead? ;)
16:35	RedNifre	(defn old-function "🕸 don't use" [] ...)
16:36	justin_smith	RedNifre: the data structures are immutable, vars, refs, atoms, and agents are mutable containers that hold data-structures, vars are the mutable container that is created when you call def
16:37	RedNifre	so can data structures contain vars/refs/atoms/agents? Or only the other way around?
16:39	justin_smith	they can, but in practice we don't
16:39	RedNifre	so the difference to java's mutable vs immutable is more cultural than technical then?
16:40	justin_smith	hlolli: the idea is to have a function that takes a single hash-map holding all the data you need, then returning a pair - a new version of that map, plus your result
16:40	justin_smith	RedNifre: all the objects we use are java objects
16:40	justin_smith	though not always the default ones the lang provides
16:40	justin_smith	for example we use regular strings, there's nothing wrong with them, they are already immutable, they work great
16:40	justin_smith	same with the simple numeric types
16:41	hlolli	ok
16:41	hlolli	someting like this http://stackoverflow.com/questions/26151509/maintaining-state-within-a-recursive-function-in-clojure ??
16:41	RedNifre	Right, but I meant that you can build objects that are as mutable as the ones in java, it's just considered bad style... unlike Haskell were things are really so immutable that you can't possibly have an atom/ref/var inside another data structure.
16:42	xemdetia	hlolli, I'm not sure if that is clear. I think justin_smith is saying something more the lines of you have f(world) -> world', and world' becomes the new 'true state'
16:43	xemdetia	the tick logic comes from synchronizing state across the world, if tick(world) -> a you can schedule something to happen at a + 5
16:43	justin_smith	RedNifre: right
16:44	oddcully	RedNifre: you saying justin_smith is sober?
16:44	hlolli	I have to hold the state somewhere. I can schedule, but the events have to be muteable and the state has to lookup again and again, that's the nature of what Im goind.
16:44	hlolli	doing
16:45	hlolli	within a recursive call would sound like plausable solution
16:45	xemdetia	hlolli, no, the idea is that you pass the world' to the next f, g, h or we and get world'' and time moves forawrd
16:45	xemdetia	since it is recursive
16:45	RedNifre	don't you have a world and an event queue, both sitting in a "pair" which sits in a ref and when a new event comes in you create a new immutable pair with the event in the queue and put that in your ref?
16:46	RedNifre	and when you feel like it you perform a tick to create a new world and an empty queue in a new pair and put that one in the ref?
16:47	xemdetia	usually I just do it as more of a queue-styled design where you read from a queue
16:47	xemdetia	and just block until you should tick or schedule ticks in the input queue
16:48	hlolli	ok, I think I understand the theory but application Im not really getting my head around. And blocking, I would just if time = time etc..
16:48	xemdetia	the 'tick' solution is inventing your own clock
16:48	xemdetia	if that wasn't clear
16:49	justin_smith	hlolli: there's no such thing as time, the function takes "now" as an argument, and returns the future
16:49	hlolli	ok, well, I'm fixed on a clock from csound, you know csound?
16:49	justin_smith	hlolli: right, sure, so follow that clock
16:49	justin_smith	and generate the future as needed
16:50	justin_smith	I'm just saying in the clojure world "time" isn't really a strong thing, you can mess with it as you like
16:50	justin_smith	so you could generate 5 next states, and keep the one you like best
16:50	justin_smith	since the function doesn't have side effects, it just takes an input, generates the next state of things
16:51	RedNifre	The trick is that your computation is faster than the time between two csound clock ticks. When this csound clock ticks, you compute the next step and you still have time to space until the next tick. (I don't know what csound is, I guess it calls one of your functions at regular intervals)
16:51	hlolli	yes, I have the number of samples coming from ksmps and that number ticks, then I send note events calculated from modulo, and then I want to store index from note-patters and rather not use much atoms/agents.
16:52	justin_smith	OK, so have a function that takes an "initial world" - the state of your orchestra - then have it call recur with the new state of the world, and also send a result to csound
16:53	justin_smith	recur can take as many args as you like, but it may be easier to pack everything into one hash-map
16:53	jbrhbr	it seems the clojure+programmatic music contingent might be thriving? :)
16:53	justin_smith	jbrhbr: and diversifying!
16:53	jbrhbr	that's how i plan on learning it myself
16:53	jbrhbr	for now i'm just lurking here and picking up little things
16:54	jbrhbr	it's cool that after so many years, a lisp dialect is finally getting some true respect
16:55	xemdetia	I guess I should ask
16:55	xemdetia	anyone doing clojure work on arm soc?
16:56	hlolli	ok, it's almost excacly like I've been doing things so far. I know I can experiment more with recursion, so I will do that first and I can have probably better questions later. But how is recursion on mutable variables, something to watch out for?
16:56	justin_smith	you don't need to mutate when you use recursion properly
16:56	justin_smith	that's kind of the point here
16:57	RedNifre	how do I "mutate" something that is deeply nested? Like (mutate someMap :firstKey :secondKey :thirdKey "The new value I want")?
16:57	justin_smith	when you call recur, the values you provide are the new bindings
16:57	justin_smith	RedNifre: update-in / assoc-in
16:57	RedNifre	thanks, I'll look that up.
16:57	justin_smith	,(iterate #(update-in % [:a :b :c] (fnil inc 0)) nil)
16:57	turbofail	update-in is probably one of my favorite functions
16:57	clojurebot	(nil {:a {:b {:c 1}}} {:a {:b {:c 2}}} {:a {:b {:c 3}}} {:a {:b {:c 4}}} ...)
16:57	justin_smith	RedNifre: see above
16:58	justin_smith	RedNifre: update-in gets nil, and turns it into {:a {:b {:c 1}}} then turns that into {:a {:b {:c 2}}} etc.
16:58	hlolli	yes yes. ok, I have my red bull next to me, now I program
16:58	hlolli	(hack)
16:58	justin_smith	heh :)
16:59	RedNifre	okay, I guess I understood half of that.
16:59	RedNifre	How exactly does nil turn into that deeply nested map?
16:59	justin_smith	RedNifre: between that example, the docs, and your own repl, you'll pick it up fast
17:00	justin_smith	RedNifre: I told it to look up the trail of keys [:a :b :c] and at each level it makes a new hash-map if one was not there yet
17:00	RedNifre	or is it just a feature of update-in that it treats nils as nested maps of which it can change the value?
17:00	justin_smith	otherwise it just looks in the one that was there already
17:00	RedNifre	ah
17:00	justin_smith	RedNifre: it's a feature of assoc that it turns nil into a map - update-in just leverages that
17:01	justin_smith	,(assoc nil :a 0)
17:01	clojurebot	{:a 0}
17:01	RedNifre	okay, and (fnil inc 0) creates an inc that treats nil as 0, huh?
17:01	justin_smith	RedNifre: you can probably guess how assoc-in and get-in behavir :)
17:02	justin_smith	RedNifre: exactly!
17:02	RedNifre	that's just fantastic :)
17:02	justin_smith	RedNifre: these features turn clojure into a very nice language for one-liners.
17:02	ane	if i want my app to read configuration files, is it wiser to just keep it in plain json or invent some kind of clojure-based thing that's eval'd on the fly?
17:02	justin_smith	you should see the amazing things we make the bots do around here sometimes.
17:03	ane	just a plain json object vs. what leiningen does
17:03	justin_smith	ane: option c: use slurp / clojure.edn/read-string
17:03	RedNifre	I love how you can carve a nested path out of a nil to retrieve a blob that looks like 0 to the function you feed it into :)
17:03	justin_smith	RedNifre: it's addictive
17:04	justin_smith	you might find some other languages a bit disappointing after you get used to clojure
17:04	jbrhbr	justin_smith: are you using it professionally now?
17:04	RedNifre	THough I wonder if you'd miss nil-pointer-exceptions when you end up with an incomplete map because at some point in the middle a nil popped up but got silently turned into some incomplete map.
17:04	ane	racket is cool with rackjure
17:04	justin_smith	jbrhbr: have been for a few years, yes
17:05	jbrhbr	justin_smith: nice, do you mind roughly answering where you work and what you're doing with it?
17:05	justin_smith	RedNifre: or because some co-worker changed the shape of the data and your codebase didn't have unit tests or assertions
17:05	justin_smith	RedNifre: yes, playing so fast and loose with data does have costs sometimes
17:05	justin_smith	but unit tests, prismatic/schema, hammock time (gained because coding is faster...) - these all help
17:06	ane	huh. turns out i designed my dependencies so that component was super easy to plug into it
17:06	justin_smith	jbrhbr: previously it was brochure websites using clojure as a RAD platform to push out servers, now it's a SAAS doing social graph metrics and reports for enterprise customers
17:06	jbrhbr	interesting
17:07	jbrhbr	thanks
17:07	justin_smith	np
17:08	ane	justin_smith: edn looks like just the thing
17:09	justin_smith	ane: it's easy to output edn with pr-str
17:09	justin_smith	though hand editing is nice if it's a hand edited config
17:09	ane	,(doc clojure.edn/read-string)
17:09	clojurebot	excusez-moi
17:09	justin_smith	,(require 'clojure.edn)
17:09	clojurebot	nil
17:09	justin_smith	now try
17:09	ane	,(doc clojure.edn/read-string)
17:09	clojurebot	"([s] [opts s]); Reads one object from the string s. Returns nil when s is nil or empty. Reads data in the edn format (subset of Clojure data): http://edn-format.org opts is a map as per clojure.edn/read"
17:10	ane	oh right it returns whatever it reads
17:11	justin_smith	,(get-in (clojure.edn/read-string "{:a {:b 42}}") [:a :b])
17:11	clojurebot	42
17:15	RedNifre	I'm not sure I understand ->>... if I have a keyword in a ref, why can't I do (->> someMap @someKeyword), why do I need (->> someMap (@someKeyword)) instead? I mean, (->> someMap :someKeyword) works so I don't understand why the deref needs extra parens?
17:15	justin_smith	,(macroexpand '(-> foo @bar))
17:15	clojurebot	(clojure.core/deref foo bar)
17:15	justin_smith	RedNifre: does that answer your question?
17:16	RedNifre	...n-no ..?
17:16	justin_smith	RedNifre: macroexpand shows you how a macro expands - in other words what code actually gets compiled
17:16	RedNifre	,(macroexpand '(->> foo @bar))
17:16	clojurebot	(clojure.core/deref bar foo)
17:16	justin_smith	,(macroexpand '@foo)
17:16	clojurebot	(clojure.core/deref foo)
17:17	justin_smith	any closer to getting it?
17:17	RedNifre	does it execute the macros in the wrong order?
17:17	justin_smith	RedNifre: @foo is a reader macro, it expands before your code does
17:17	bja	@ is a reader macro for deref. The code actually reads (->> someMap (deref someKeyword))
17:17	justin_smith	it because (deref foo)
17:17	RedNifre	,(macroexpand '(->> map (@keyword)))
17:17	clojurebot	((clojure.core/deref keyword) map)
17:18	ane	try without the parens
17:18	RedNifre	,(macroexpand '(->> map @keyword))
17:18	clojurebot	(clojure.core/deref keyword map)
17:19	justin_smith	RedNifre: do you understand how ->> and -> operate by rewriting forms?
17:19	justin_smith	,(macroexpand '(-> a b c))
17:19	clojurebot	(c (b a))
17:20	RedNifre	I don't understand what "rewriting forms" means exactly, I just stumbled across ->> and thought it turns (->> e d c b a) into (a (b (c (d e))))
17:20	justin_smith	right, and that's a list transformation, right?
17:20	RedNifre	...oookay.
17:20	justin_smith	it's rewriting the input form into a different shape before it gets compiled
17:20	RedNifre	ok
17:20	justin_smith	a form being a list you intend to get compiled
17:21	RedNifre	does "form" mean "part of the AST"?
17:21	justin_smith	pretty much - technically there's a real AST that isn't just your clojure intput file
17:21	justin_smith	but close enough for this convo I think :)
17:21	RedNifre	ok :)
17:22	bja	as an aside, there are actually two asts right? one that the official clojure compiler uses, one that tools.analyzer and friends use. or are those the same?
17:22	bja	I haven't delved into those waters yet
17:22	justin_smith	bja: they each create their own representation, and they don't use the same data structures no, so yeah, they have their own thing they call an AST
17:23	RedNifre	Now hang on... how can (->> map @keyword) possibly expand into (deref keyword map)? That looks like @keyword expanded into two things and I thought that was impossible?
17:23	ane	precedence
17:23	ane	it's not @keyword getting expanded twice
17:23	justin_smith	RedNifre: (->> map @keyword) => (->> map (deref keyword)) => (deref keyword map)
17:23	ane	it's first ->> and then @keyword
17:23	RedNifre	No, I think earlier it was said that one macro can't expand into two things... when I tried to create a macro that expands both into the key and value of a map?
17:23	ane	or i don't know what the order is
17:24	justin_smith	RedNifre: it's still one thing, one list
17:24	justin_smith	RedNifre: but there's no rule that says ->> can't turn one item in a list into two items in a list
17:24	justin_smith	it's just that you can only return one value to a caller
17:24	RedNifre	...
17:24	justin_smith	so the compiler calls ->> to get the form to compile (or further macro expand) and gets a single list, that's all
17:25	RedNifre	what does "return one value to a caller" mean in the context of macro expansion? I thought the macro sort of returns source code to the source code file?
17:25	justin_smith	RedNifre: the restriction would apply to @ - @keyword can't return two separate items
17:25	bja	the value returned from ->> is '(e (d (c (b a)))), which replaces (->> a b c d e)
17:25	justin_smith	RedNifre: the compiler calls a macro, and the macro returns the form for the compiler to expand or compile
17:25	RedNifre	Can you show me the first step of macro expansion for (->> map @keyword)?
17:25	justin_smith	RedNifre: I did above
17:26	justin_smith	RedNifre: (->> map @keyword) => (->> map (deref keyword)) => (deref keyword map)
17:26	justin_smith	that's the step by step
17:26	RedNifre	hm, I feel like I nearly get it... one sec.
17:27	bja	,(read-string "(->> map @keyword)")
17:27	clojurebot	(->> map (clojure.core/deref keyword))
17:27	Bronsa	RedNifre: @ is a reader macro, reader macros get expanded at read-time, before macroexpansion time
17:27	Bronsa	the macro never sees @
17:27	justin_smith	yay, more details (and of course more accuracy)
17:28	RedNifre	What? So there are (at least) two categories of macros, one type goes first, then the other ones?
17:28	justin_smith	RedNifre: and macros are recursive
17:28	justin_smith	the forms that are returned by one macro can contain other macros to expand
17:28	Bronsa	RedNifre: technically, yes. you can't write reader-macros though, those are reserved by the clojure implementation
17:29	RedNifre	...but I guess a regular macro can't expand to a reader macro because that would be too late since the reader macro expansion phase is already over?
17:29	justin_smith	right, unless the macro ended up invoking the reader
17:29	bja	well, there are places where macros are expanded. the first as when your source code is "read" (things like @ are expanded here). the other common place is as a precursor to execution, macros are evaluated recursively until there are no more macros, then the code is executed.
17:29	RedNifre	...
17:29	justin_smith	which means you are probably doing something very stupid and or something very clever if not both
17:30	bja	actually, more precisely, the current form is macroexpanded recursively until there are no more macros.
17:30	RedNifre	well, I understand the first step of the expansion but I don't understand why (->> map (deref keyword)) doesn't turn into ((deref keyword) map)... where do the parens go?
17:30	RedNifre	...ooooh
17:30	justin_smith	RedNifre: thats just what ->> does
17:30	RedNifre	That's a feature of ->> right, to allow for curried functions?
17:31	justin_smith	it takes each result and inserts it into the next form
17:31	justin_smith	not really currying
17:31	RedNifre	So that I can do (->> 1 (+ 1)) and it turns that into (+ 1 1)?
17:31	justin_smith	but to allow for functions of more than one arg, yes
17:31	justin_smith	right
17:31	RedNifre	Okay, then it all makes sense. :)
17:31	justin_smith	RedNifre: I hope you see what I mean about rewriting forms now
17:32	RedNifre	Oh, there was so much content in the last few minutes, I'm not sure I remember which point about rewriting forms you refer to now :)
17:32	justin_smith	hehe
17:32	RedNifre	enlighten me :)
17:32	justin_smith	it was my initial answer, about what ->> was doing
17:32	justin_smith	and why it was doing something so dumb - because it's just a dumb list-recombining rule
17:34	RedNifre	,(let [needs-two (fn [a b] (+ a b))] (->> 1 (needs-two 1)))
17:34	clojurebot	2
17:34	RedNifre	looks a lot like currying to me
17:35	RedNifre	and what's "->" then?
17:40	justin_smith	RedNifre: but currying creates functions, and ->> creates forms for the compiler to compile
17:40	justin_smith	RedNifre: it just puts the previous form in the second place rather htan last
17:40	RedNifre	,(macroexpand '(-> a b c))
17:40	clojurebot	(c (b a))
17:40	RedNifre	,(macroexpand '(->> a b c))
17:40	clojurebot	(c (b a))
17:40	justin_smith	,(macroexpand '[(-> (a b) (c d) (e f)) (->> (a b) (c d) (e f))])
17:40	clojurebot	[(-> (a b) (c d) (e f)) (->> (a b) (c d) (e f))]
17:40	justin_smith	err
17:40	justin_smith	,(macroexpand '(-> (a b) (c d) (e f)))
17:40	clojurebot	(e (c (a b) d) f)
17:40	justin_smith	,(macroexpand '(->> (a b) (c d) (e f)))
17:40	clojurebot	(e f (c d (a b)))
17:40	justin_smith	see how different?
17:40	justin_smith	->> puts the form into the last place of the next form
17:40	justin_smith	-> puts the form into the second place in the next form
17:40	RedNifre	Okay, I see how ->> is useful for chained functions, but -> looks like a very special case... when do you need that one?
17:40	HoneyBadger	Sup peopel
17:40	HoneyBadger	*people
17:40	justin_smith	RedNifre: -> is good for map operations where each step returns a new hash-map
17:40	justin_smith	RedNifre: ->> is good for seq operations where each step returns a new sequence
17:40	RedNifre	HoneyBadger second day...
17:40	HoneyBadger	yup
17:40	justin_smith	because the hash-map is usually the second arg, for hash-map functions
17:40	justin_smith	get, assoc, dissoc, get-in, update-in, etc.
17:40	justin_smith	and a sequence is usually the last arg - map, reduce, filter, apply, etc.
17:40	TimMc	I use both quite a bit.
17:40	HoneyBadger	i thought it was first?
17:40	TimMc	HoneyBadger: First arg is second element in the list.
17:40	HoneyBadger	oh i see
17:40	TimMc	(foo 1 2 3) <- the first element is the fn you are calling :-)
17:41	RedNifre	Oh, you mean when you don't do (get 3 someMap), it's when you do (someMap 3)?
17:41	RedNifre	hm...
17:41	RedNifre	can you give me a real world example for ->?
17:42	turbofail	(-> {:foo 0} (update :foo inc) (assoc :bar 10))
17:42	justin_smith	turbofail: clojurebot is here you know
17:42	turbofail	,(-> {:foo 0} (update :foo inc) (assoc :bar 10))
17:42	clojurebot	{:foo 1, :bar 10}
17:43	RedNifre	,(macroexpand '(-> {:foo 0} (update :foo inc) (assoc :bar 10)))
17:43	clojurebot	(assoc (update {:foo 0} :foo inc) :bar 10)
17:44	RedNifre	okay, that makes sense, but I thought functional style would put the data last anyway, so why are update and assoc "backwards" like that?
17:45	justin_smith	RedNifre: (assoc m :a x :b y :c z ...) works better if the thing to assoc onto goes first
17:45	justin_smith	or I like it that way, at least
17:49	RedNifre	Is there something like Hoogle where you can type a function signature and it shows you all functions in the standard library that match it?
17:51	RedNifre	For example, now I'm looking for a function that cuts an element out of a list that is nested in some maps, how do I find such a function?
17:52	thearthur	RedNifre: I don't think such a search exists, the type signature of a whole lot of functions is sequence to sequence for instance
17:52	RedNifre	hm, I guess I can just use a higher order function in an update-in...
17:52	thearthur	would update-in do it for you
17:53	RedNifre	I think it would if I use (fn [innerList] (removeTheElementAndReturnTheRemainingList elem innerList) as the update function...
17:53	justin_smith	RedNifre: Raynes made findfn
17:54	justin_smith	RedNifre: it takes some args and a result, and finds all the functions that give that result for your args
17:54	RedNifre	sounds good.
17:54	RedNifre	do we have a bot for that? :)
17:55	justin_smith	RedNifre: lazybot, which is currently on vacation
17:56	RedNifre	I'll just go with the cheat sheet, that one will probably have most functions I need on it, at least for the next couple of days I guess.
17:57	RedNifre	I mean "remove an element from a list and return what's left of the list" is probably on the sheet...
17:59	RedNifre	So, vectors are like fixed size arrays and lists are linked lists, right? I guess this means that since I want to create rooms that contain things that can move from room to room, the content of a room should be a list, not a vector, huh?
18:00	turbofail	vectors in clojure aren't fixed-size arrays
18:00	turbofail	they're much cooler than that
18:00	RedNifre	how do they differ from lists?
18:01	turbofail	you can efficiently append to the end of a vector
18:01	turbofail	you also get log32(n) random access
18:01	RedNifre	...but can I also efficiently cut something out in the middle?
18:01	turbofail	no, not with normal vectors. but you can if you use core.rrb-vector
18:01	amalloy	RedNifre: the middle is a bad place. stay away from the middle
18:02	RedNifre	Right, but since lists are linked, removing something from the middle is no problem there, huh? Should be O(listSize/2) = O(n), no?
18:02	turbofail	well if you're counting O(n) as good enough, then you can do that with vectors too
18:02	RedNifre	well, it should also be O(n) for the vector, but a much worse O(n)... hm...
18:03	RedNifre	okay, so if I have a list and I want a list that is like the first except that an element in the middle is missing, what should I do?
18:03	turbofail	not really. it's just about the same, you take a subvector and then re-append the parts you want after it
18:03	RedNifre	now that I think of it, sets could also work.
18:03	turbofail	actually the vector might still be faster
18:04	RedNifre	I guess the set would still be faster, right?
18:04	turbofail	well yeah
18:04	justin_smith	RedNifre: some combination of take / drop / concat is the usual answer, there is no nice way to do it, so nothing built in
18:04	luma	,(remove #{:bar} '(:foo :bar :baz))
18:04	clojurebot	(:foo :baz)
18:04	justin_smith	(regarding dropping out of the middle of a list)
18:05	luma	remove drops all items that match the predicate, so be sure that only the one you want to drop matches
18:05	amalloy	RedNifre: O(n) for a single operation is pretty bad
18:06	amalloy	so like, yes, inserting or removing into the middle of a list is O(n), but so is copying the entire list
18:06	turbofail	if what you want is a set then you should use a set
18:06	RedNifre	Depends. If I use a set but want to display it in a deterministic fashon I would have to display it sorted in O(n*log(n))...
18:07	turbofail	there's sorted sets if you're into that
18:08	turbofail	anyway n*log(n) isn't much overhead over the linear time it takes to display it regardless
18:14	RedNifre	Wow (remove #{:bar} #{:foo :bar}) is pretty weird...
18:14	RedNifre	Is there a more normal remov like (remove :bar #{:foo :bar}) ?
18:15	turbofail	,(disj #{:foo :bar} :bar)
18:15	clojurebot	#{:foo}
18:15	turbofail	remove is for sequences
18:17	marshzor	,(print "hello, world!")
18:17	clojurebot	hello, world!
18:19	RedNifre	,(print "/me thinks")
18:19	clojurebot	/me thinks
18:19	RedNifre	meh
18:30	RedNifre	Are there tuples or do I just use vectors?
18:31	amalloy	generally just vectors
18:34	RedNifre	so #{} is a set and #() is a lambda, but what is #[] ?
18:35	justin_smith	RedNifre: nothing!
18:35	RedNifre	the repl says something about a reader tag which must be a symbol...
18:35	RedNifre	...but I guess that's just the REPL's way of saying "nothing!".
18:36	justin_smith	,(java.util.Date.)
18:36	clojurebot	#inst "2015-09-24T22:37:03.302-00:00"
18:36	averagehat	,http://symbolhound.com/ is good for these kind of questions usually
18:36	clojurebot	#<RuntimeException java.lang.RuntimeException: Invalid token: http://symbolhound.com/>
18:37	justin_smith	RedNifre: note how dates print
18:37	justin_smith	#inst
18:37	justin_smith	so it's looking for a symbol, and finds [] instead
18:37	RedNifre	ok
18:38	justin_smith	,(defrecord R [])
18:38	clojurebot	sandbox.R
18:38	justin_smith	,(R.)
18:38	clojurebot	#sandbox.R{}
18:38	justin_smith	see how that one gets sandbox.R as its symbol
18:38	marshzor	if I have a function that returns a boolean, is there a function that returns the negation of a function?
18:39	justin_smith	marshzor: complement
18:39	marshzor	ty justin_smith
18:39	justin_smith	,(def not-a-list? (complement list?))
18:39	clojurebot	#'sandbox/not-a-list?
18:40	justin_smith	,(not-a-list? (range))
18:40	clojurebot	true
18:40	justin_smith	,(not-a-list? (list))
18:40	clojurebot	false
19:42	jsabeaudry	just watched the talk about om next, I'm excited but I can't find the code, is it not on github.com/omcljs/ ?
19:46	justin_smith	any suggestions for a simple repl function that would test how much heap my clojure process is willing to take from the OS?
19:46	justin_smith	especially if I could incrementally jump up heap usage and see it go up in htop
19:47	RedNifre	When I print some data structures, is there a way to format the output? Currently it's all in one line which makes it hard to read large data structures.
19:48	justin_smith	RedNifre: your repl should map clojure.pprint/pprint to pprint
19:49	justin_smith	and it does that nicely
20:21	futuro	jsabeaudry: I don't have a definitive answer, but it searching through the codebase brings up references to 'next', so my guess is that it's been merged in
20:21	futuro	but that's only a guess
20:44	jsabeaudry	futuro, oh, that would explain why the om next demo I found include om and nothing named om next, thanks for your help!
21:18	zakwilson	Is http://clojure-android.info/ a reasonable place to get started for using Clojure on Android, or is there somewhere else I should be looking?
21:51	TEttinger	zakwilson: also try joining their IRC, #clojure-android here on freenode
21:51	TEttinger	there's slack too. I should probably get a slack account.
21:57	zakwilson	TEttinger: I joined the IRC.
22:03	gganley	I'm looking into writing a SAT solver. I started in haskell using Lens' but I also use clojure in my spare time and I remembered about core.logic. Is that something that would be useful for doing things like unit propogation and other search space optimizations or is it used for other things. I have no prior knowlage about the library and I'm currently looking it up
22:17	TEttinger	gganley: IIRC core.logic is an implementation one of the MiniKanren or MuKanren or something prolog-like logic solvers
23:42	flaing	bonjure