#clojure – 2015-09-20

2015-09-20

00:09	TEttinger	domokato_: still around?
00:10	rritoch	What is a "dev-resources" folder for? I've never really noticed it before but when I setup a new clojure project in eclipse it added a dev-resources to the java build path but didn't actually create the folder.
00:11	rritoch	I also don't recall seeing dev-resources in any project, or ever needing anything comparable.
00:11	rhg135	resources you don't want to ship
00:14	rritoch	rhg135: Cool thanks. So it's more useful for proprietary projects, like a licence key for developers to bypass restrictions, or for parts of the system that aren't yet ready for release.
00:23	rritoch	rhg135: Is there a comparable folder for source code? Such as a main entry point that isn't needed in a distributable library but is provided for testing other than unit tests?
00:38	amalloy	rritoch: you can roll your own by adding to :source-paths in your :dev profile
00:39	amalloy	nothing built in that i know of. i think mostly nobody minds including their -main in a library jar
00:41	rritoch	amalloy: Thanks. I'm not entirely sure I'll ever need that, I haven't needed it so far, but at least I can add it to my stockpile of coding trivia :)
01:15	rritoch	Is there a "best practice"/naming convention for a "with" function that returns a promise instead of a value? Such as (with-gui-thread #(do (print "GUI OK") true) . Using with for this seems deceptive since the return value won't yet be fully defined when it returns.
01:17	justin_smith	when you say promise, do you mean function?
01:17	justin_smith	because we have promises, and that isn't one
01:19	rritoch	justin_smith: I'm writing a function, that with the aid of a macro and some other magic is going to perform a given function and arguments and return a promise. That promise will be fulfilled when the function is executed in that other thread.
01:19	justin_smith	OK, your code example didn't have any promise in it, so I wasn't sure
01:20	rritoch	sorry, t was just simpled that that function was in some way defined to return a promise instead of a value.
01:20	rritoch	err
01:20	rritoch	It was just implied
01:21	jeremylite	rritoch: "with" usually implies some additional context. in this case, it's your gui thread. so i think that's fine
01:21	jeremylite	to return a promise
01:22	justin_smith	I still have no idea where the implied promise was supposed to be in that example. Does with-gui-thread return it? does the anonymous function return it?
01:22	justin_smith	I mean the one that never gets called
01:23	rritoch	justin_smith: Yes, with-gui-thread will create and return a promise
01:24	jeremylite	rritoch: on second though, maybe "on-gui-thread" or "invoke-gui" or something like that
01:24	rritoch	I was just thinking that with seems deceptive, like maybe it should be future-with or some other name.
01:25	justin_smith	to my eye, a with-* is a macro that takes your code and puts it in some other context, so it would take a &body instead of a lambda
01:25	jeremylite	yeah
01:25	justin_smith	also, how is this different from future - just the fact that it runs something on a specific existing thread?
01:25	rritoch	jeremylite: Hmm, I think invoke is a good idea, like "invoke-with"
01:26	rritoch	justin_smith: Yes, that's the only difference. It is going to run on a specific thread.
01:27	justin_smith	I'd make that function, and call it call-in-gui, then make a macro that expands to putting the body in an anonymous function supplied to call-in-gui and call that with-gui-thread
01:28	justin_smith	and yeah, return a promise that the caller can access later
01:35	rritoch	justin_smith: If I use a macro instead of a function won't that eliminate the possiblity of being able to map over it? Such as (map #'invoke-with-gui-thread job-list)
01:36	justin_smith	rritoch: I said invoke a function, the macro is just a convenience
01:36	justin_smith	and it becomes inconvenient if you want to map (but don't do that, because map is not for side effects)
01:37	justin_smith	rritoch: I only suggested the macro because you suggested with-foo and that's how a with-foo would work, turn a body of code into a function and then put it into the right context for evaluation
01:38	rritoch	justin_smith: Well, I'm still debating function -vs- macro for this, the function is using a macro internally. I really don't know a way to do this without macros.
01:39	justin_smith	def is a macro, let is a macro, everything uses macros internally
01:39	jeremylite	rritoch: he's talking a function like (defn call-on-gui [f] (call-on-thread thread f)) and a macro like (defmacro [&body] `(call-on-gui (fn [] ~@body)))
01:40	jeremylite	the functino is more useful, but the macro adds sugar
01:41	justin_smith	functino, heh, I do that typo all the time
01:42	jeremylite	lol
01:42	justin_smith	we should totally make something called functino for making small inline functions or something
01:42	jeremylite	justin_smith: i keep typing "litearl" instead of a "literal" and i think of james earl jones being high
01:42	justin_smith	haha
01:43	jeremylite	you know, functino, the core.logic operator for functin, duh
01:44	justin_smith	"duude - hear me out now, what if the death star is just a symbol of our hubris, man, like we have an intergalactic empire but want to be gods, create worlds, destroy them" puffs
01:45	emdashcomma	well
01:45	emdashcomma	you're not wrong
01:45	jeremylite	lol
01:46	justin_smith	I can totally picture Vader getting stoned. Of course he would vape though.
01:48	justin_smith	alternately, Thulsa Doom, he would roll blunts
01:48	emdashcomma	he'd try to force choke the wall, and giggle unconrtollably
01:48	justin_smith	haha
01:51	justin_smith	emdashcomma: force lightning to spark the bowl, followed by a force-choke on his piece instead of using a carb
02:11	rritoch	What about x-quiet vs x-stfu , I really prefer the stfu but god-forbid clients ever look at the code.
02:11	domgetter	Is there a way to make a set of maps where the uniqueness of the members is determined by one of the values of a key each of them has?
02:12	justin_smith	domgetter: sorted-set-by will only keep 1 of each return value for its sorting function
02:13	domgetter	awesome Ill look at the docs for that, thank you
02:13	justin_smith	domgetter: so if what you want is to keep only one map for a given value of :key, then (sorted-set-by :key ...) would do what you want (as a side effect of the sorting that I am sure you don't need)
02:13	rritoch	my last question was rhetorical, for entertainment purposes only.
02:13	justin_smith	,(sorted-set-by :k {:k 1} {:k 2 :v 1} {:k 2 :v 2})
02:13	clojurebot	#error {\n :cause "clojure.lang.Keyword cannot be cast to java.util.Comparator"\n :via\n [{:type java.lang.ClassCastException\n :message "clojure.lang.Keyword cannot be cast to java.util.Comparator"\n :at [clojure.core$sorted_set_by invokeStatic "core.clj" 412]}]\n :trace\n [[clojure.core$sorted_set_by invokeStatic "core.clj" 412]\n [clojure.core$sorted_set_by doInvoke "core.clj" -1]\n [cloj...
02:14	domgetter	justin_smith: well I do want them sorted by their :create_at date, but I want them to be unique by their :id
02:14	justin_smith	err...
02:15	justin_smith	,(sorted-set-by #(apply compare (map :k %&)) {:k 1} {:k 2 :v 1} {:k 2 :v 2})
02:15	clojurebot	#{{:k 1} {:k 2, :v 1}}
02:16	domgetter	And that will enforce uniqueness and sortedness on the same key, correct?
02:17	justin_smith	yes
02:17	domgetter	okay cool, thank you
02:17	justin_smith	that is how sorted-set-by works - it always enforced uniqueness by the sorting key
02:44	rritoch	I ended up using a macro for my invoke-with ... it was the cleanest solution.
03:08	rritoch	Short of assigning all defrecord fields as atoms, is there a way to establish two-way bindings between a defrecord and a user interface? I need events triggered each time a field changes so the system can update the GUI.
03:11	amalloy	since a record (which is just a fancy map) is immutable, you can't really have a specific instance of defrecord be synched with something that can change. you could, of course, have an atom that points to different records over time
03:11	justin_smith	sounds like react
03:11	justin_smith	the api for reagent is pretty close to that
03:22	domgetter	Is there a reason why this is happening? https://gist.github.com/anonymous/e8e658619f9b92f2bfca
03:22	domgetter	I thought swap! ran apply, so I wouldn't get a nested vector
03:22	rritoch	Thanks,. For this case it sounds like I need two record types, one for values which don't change often so it can reasonably be maintained in a "watched" atom, and another which contains values which change often and need individual fields watched.
03:22	justin_smith	domgetter: no, swap! does not run apply
03:22	justin_smith	domgetter: just use into, or provide the 3 and 4 as separate args
03:23	justin_smith	,(def a (atom [1 2]))
03:23	domgetter	How do I supply them as separate args
03:23	clojurebot	#'sandbox/a
03:23	justin_smith	,(swap! a conj 3 4)
03:23	clojurebot	[1 2 3 4]
03:23	domgetter	that is, if I can't do it literally
03:23	justin_smith	,(swap! a into [5 6])
03:23	clojurebot	[1 2 3 4 5 ...]
03:23	justin_smith	domgetter: literally works, as above
03:23	domgetter	ah I see
03:23	domgetter	ok thank you
03:24	justin_smith	or you can use into if you need to provide them as a coll
03:24	justin_smith	domgetter: it mentions apply ... args but note that it's arg list has & args
03:25	justin_smith	so args will be a coll, containing all your args, I hope that makes it more clear
03:25	justin_smith	(doc atom)
03:25	clojurebot	"([x] [x & options]); Creates and returns an Atom with an initial value of x and zero or more options (in any order): :meta metadata-map :validator validate-fn If metadata-map is supplied, it will become the metadata on the atom. validate-fn must be nil or a side-effect-free fn of one argument, which will be passed the intended new state on any state change. If the new state is unacceptable, the validate-fn should return false or thro
03:25	justin_smith	(doc swap!)
03:25	clojurebot	"([atom f] [atom f x] [atom f x y] [atom f x y & ...]); Atomically swaps the value of atom to be: (apply f current-value-of-atom args). Note that f may be called multiple times, and thus should be free of side effects. Returns the value that was swapped in."
03:25	domgetter	ah okay, that makes sense
03:25	justin_smith	oh, that's a bad doc string :P
03:26	domgetter	so I'm not crazy :P
03:26	justin_smith	if you are going to refer to "args", then bind args in the doc string, hah
03:26	justin_smith	I mean in the args list
03:26	justin_smith	but you get what I mean
03:26	domgetter	I think into works for what I want
03:29	justin_smith	the funny thing is when you combine swap! with update*
03:29	justin_smith	,(swap! a update 2 * 42)
03:29	clojurebot	[1 2 126 4 5 ...]
03:29	justin_smith	like forth in reverse
03:53	sotojuan	justin_smith: do you ever sleep? Every time I log on you are here ;D
04:19	roelof	Hello, Im looking at living clojure for learning clojure. Can I start with the exercises and read the chapters that are involved or can I better read everything first and do the exercises after it
04:21	domgetter	roelof: Probably better to read a chapter and then try the exercises.
04:22	roelof	domgetter: that is what I mean. but the book has two parts. First the explanations and after that a training part.
04:38	amalloy	justin_smith: in my 1.6 repl that docstring reads "args", not "..."
04:39	roelof	domgetter maybe first read everything and look at the examples and then do the training weeks
04:50	javahippie	roleof: why not 'code along' on your own while reading the theory? This way you could get a better grasp of it and afterwards do the trainings
04:53	domgetter	roelof: My only advice is to not spend too much time thinking about the best way to do it. Just choose a strategy and do a little each day.
04:54	roelof	javahippie: I could do that but then I have to have a idea what to programm
04:54	roelof	domgetter: oke, thanks for the tip
04:56	domgetter	Once you learn that you can do things, you'll dream up projects, I guarantee it
04:56	domgetter	And the more tools in your toolbelt, the more imaginative and confident you'll be
04:56	domgetter	And Clojure offers some pretty powerful tools :)
04:56	roelof	domgetter: I think I know a project for in the future. or a ecommerce site or a accounting site
05:12	javahippie	roleof: I meant, coding along the examples in the relp. Maybe, read a chapter about sequences, fool around with them in the repl
05:12	roelof	javahippie: thanks for the tip
05:14	roelof	I have a quick read of chapter 1 of the Living book and I think I can do something with it
05:19	roelof	First install clojure on my ubuntu box :)
05:27	roelof	Can I just do apt-get clojure or can I better make a project and use the newest version as a dependency
05:28	javahippie	roleof: does your book mention leiningen?
05:29	roelof	yes, it does
05:29	roelof	it says first make a project
05:30	javahippie	that sounds good. See following link: http://clojure.org/downloads section 'Get Clojure via Leiningen'.
05:31	roelof	aha, and I see if I do lein repl clojure 1.7.0 is installed :)
05:31	javahippie	Yep, it is part of the initialization routine (if you want to call it that way)
05:45	roelof	Thanks all, Im now working trought chapter 1 of living clojure
05:47	javahippie	roleof: have fun! maybe give a little feedback from time to time about how you like the book ;)
05:56	domgetter	If I'm in the lein repl, how do I load core.async so I can play with channels?
05:57	domgetter	Or do I have to explicitly set it as a dependency in a project.clj file?
05:59	javahippie	As far as i know, dynamically adding dependencies is quite difficult, without additional tools. I remember it being a classloading issue
05:59	javahippie	I prefer to work with the project.clj
05:59	domgetter	ah okay fair enough
06:00	javahippie	never tried it, but maybe this is what you are looking for: https://github.com/pallet/alembic
06:13	roelof	javahippie: did you write it ?
06:17	javahippie	Oh, no. Far from it :D I am just interested in the quality of different books. I find it incredibly difficult to keep track about it
06:23	Raynes	Well AWS sure just ain't doing well right this moment.
06:23	Raynes	DynamoDB is ded and apparently everything depends on it according to newrelic telling me all my shits dying :D
06:24	Raynes	How's everyone else's Sunday morning?
06:28	roelof	javahippie: I did read the first chapter and did the examples and I like it. Everything is explained very well on a way a beginner understand it
06:31	mungojelly	what does ^{} mean
06:36	mungojelly	ok so my problem involves numerous things that are just slight variations on one another, which persistent data structures are awesome for, except i'd also like to persist them as in write them to disk sometimes, how can i remember things and maintain that space sharing, except of course to use datomic
06:41	hellofunk	mungojelly: ^{} is for adding meta data, not something you will need most of the time
06:41	hellofunk	Raynes: pretty good, yours? still in l.a.?
06:41	Raynes	Well pretty terrible since all my shit's dead and all but hey I could be dead.
06:42	Raynes	Still in LA, yessir.
06:42	lodin___	mungojelly: IIRC transit does that, i.e. it can refer to a previously serialized entry in the structure.
06:42	hellofunk	your shit is dead? isn't shit supposed to be dead? that is why it is flushed.. ?
06:42	mungojelly	hellofunk: i'm not trying to do it but i'm reading the code for JDBC and it's used a lot there so i wanted to understand what i'm reading :)
06:42	Raynes	You're looking for lodin- sir.
06:42	Raynes	Not hellofunk.
06:42	hellofunk	mungojelly: for understanding basic logic, you don't really need to pay attention to metadata most of the time
06:43	Raynes	Oh wait, nevermind
06:43	Raynes	I can't read.
06:43	Raynes	I should go to bed.
06:43	hellofunk	Raynes: how are those fires out there, did you start them?
06:43	Raynes	Or play Heroes of the Storm.
06:43	Raynes	I mean unless I somehow stepped on a butterfly and caused a hurricane in us-east-1, doubt it was my fault.
06:43	mungojelly	lodin-: this transit-clj thing from cognitect? ok i'll learn about that thanks :)
06:45	mungojelly	in general it seems sad to me how bad our programs are at communicating so far, i bet sometime soon all the programs will start talking, the silence will end, but we'll think about it just in terms of some particular data exchange format, like how we understood the hypertext transformation to be about "HTML"
06:46	lodin-	mungojelly: Right. I'm not 100 % sure, so please let me know if I remembered correctly. :-)
06:55	mungojelly	lodin-: transit seems to know how to serialize basic values, compound values and can be extended by teaching it new types, but i don't see anything about preserving structure sharing or references. looks useful in general, certainly better than speaking directly to JSON! :)
06:57	ianhedoesit	am I stupid or is there a problem with the invite site for the clojurians slack channel?
06:57	ianhedoesit	clojurians.net gives an error when I try to get an invite. it's saying the token provided has insufficient privileges, basically.
07:06	mungojelly	lodin-: oh ok well i'm not sure i quite understand yet how to do it but this http://swannodette.github.io/2015/02/19/transit-js-caching/ says you can get it to cache references by writing custom handlers that say to do the caching hm
07:24	lodin-	mungojelly: I have not used transit myself, so I thought that the caching was not only for map keys.
07:39	mungojelly	lodin-: it's for nothing and anything, it'll handle things based on a custom handler, so if your write handler says put my symbol by which i mean backreference, and your read handler reads and reinflates the back references, voila
07:41	mungojelly	i don't need to drag the data back out often so i'm trying the strategy of just compressing it, i find that's wiser often than trying to be clever :)
08:05	visof	hi guys
08:05	visof	what is the performance of take and concat?
08:06	roelof	hello, how can I take care that a character is printed out instead of #<Atom@1322f9d: here is my code so far : http://lpaste.net/141361
08:07	domgetter	roelof: You need to "dereference" the atom. Every time you want what's inside an atom, put a @ in front of its name
08:07	roelof	oke, I will try that
08:08	mungojelly	,(let [a (atom "contents")] (println @a))
08:08	domgetter	so on line 28, it should be (println @directionX)))))
08:08	clojurebot	contents\n
08:09	mungojelly	that's the first time i ever said @ yay it worked
08:09	roelof	domgetter: then there is more wrong. I do not get a output at all
08:09	domgetter	also, on lines 22 and 25, you need @thorX
08:10	domgetter	since it's an atom, and youre trying to compare its value
08:10	roelof	oke, changed it
08:10	roelof	I try to do a challenge of codeingame with clojure
08:11	domgetter	May I ask what (= thorX > lightX) means?
08:11	domgetter	are you trying to check if @thorX is equal to lightX? Or are you trying to check if it's larger than lightX? Or something else?
08:12	roelof	of course it means if the current postion (ThorX) is smaller then the end-position(LightX) then the direction must be W
08:13	domgetter	I think you might want (< @thorX lightX)
08:13	roelof	you are right
08:13	domgetter	that says "@thorX is less than lightX"
08:16	roelof	oke, now this part (if (< @thorX lightX) (swap! directionX "E")) gives this error message : xception in thread "main" java.lang.ClassCastException: java.lang.String cannot be cast to clojure.lang.IFn
08:17	domgetter	roelof: You want to use reset! instead of swap! to set an atom to something in particular
08:17	domgetter	you'd use swap! if you want to use a function on the atom, but here, you just want to set it to the string "E" directly
08:17	roelof	oke, I wil try that
08:18	domgetter	change (swap! directionX "E") to (reset! directionX "E")
08:18	mungojelly	the second argument to swap! is a function that gets applied to the thing to change its value, like (swap! thing inc) is like thing++
08:20	roelof	yes, first part is working :)
08:21	roelof	is this good clojure : http://lpaste.net/141362
08:22	domgetter	looks alright. The important thing is, do you understand it?
08:47	crocket	uncle bob said clojure deserved to be the last programming language or the seed of the last programming language in 2011.
08:49	crocket	The last programming language to rule it all.
08:50	crocket	If only clojure could handle the metal directly.
08:51	roelof	yes, I wrote every piece of it
08:52	roelof	then now the y part and chancing the ThorX and ThorY. I can use the swap for the last one
08:54	roelof	but is every time using a def for a variable in a loop is good ? Can I not better do the def before the loop and do also a reset! to make them empty ?
08:55	mungojelly	there is no metal, modern cpus just pretend to be the old cpu architecture so that's a virtual machine now too
08:58	mungojelly	they split the asm "instructions" into parts, they smashed even those, and then the actual metal rearranges how those smashed partial instructions are pipelined for efficiency, so it jit compiles everything down into a language that very few humans can begin to understand and that literally no one speaks
09:08	xikuuky	Hey guys.
09:09	xikuuky	I came from a Hylang/Python background, I use functional coding and what not. Will Clojure be a good language?
09:09	mungojelly	xikuuky: i just started a few weeks ago but in my opinion clojure is a ridiculously good language. so good.
09:10	mungojelly	what's a hylang, never heard of it, sounds like it would be the programming language of hyrule
09:10	xikuuky	mungojelly: Is it static?
09:10	xikuuky	mungojelly: A Pythonic Lisp
09:10	mungojelly	is what static? are what static?
09:11	xikuuky	mungojelly: Static is where every type is set in stone while dynamic is where every type is defined on a need to know basis.
09:11	mungojelly	it allows mutable state but strongly encourages a style focused on immutability, by providing and supporting awesome practical immutable structure
09:11	mungojelly	oh in its typing. it's very dynamic.
09:12	crocket	Is it possible to have dependent types in clojure?
09:12	crocket	Would it be wieldable?
09:12	mungojelly	there's a typed variant called typed clojure that i've just started to find out about, but around here it's mostly untyped.
09:12	xikuuky	mungojelly: Yay!
09:13	xikuuky	I really don't like static languages. I worked with C#, F#, VB, the whole deal and I didn't think it was so great all the time/
09:17	mungojelly	in fact the style around here is very terse, there's this clever thing where hashmaps can be used as functions, from key->value, and also hashmap keys can be used as functions, from map->value, which sounds odd for a moment but then reads just splendidly
09:17	mungojelly	,({:a 1 :b 2} :a)
09:17	clojurebot	1
09:17	mungojelly	,(:a {:a 1 :b 2})
09:18	clojurebot	1
09:19	mungojelly	so that's used eeeeeeeeeverywhere to just say, i want the :this from the {that}, i've got a map called stuff, i want the thingy from the stuff, so either (:thingy stuff) or (stuff :thingy) gives me what i want
09:22	crocket	Can clojure go close to the metal?
09:22	mungojelly	,(let [thingy {:a 2 :b 5}] (* (thingy :a) (thingy :b)))
09:22	clojurebot	10
09:22	mungojelly	crocket: there is no metal
09:23	crocket	You don't know what I mean by metal.
09:23	budai	is it possible to check if a record implements a specific protocol?
09:24	gfredericks	,(doc satisfies?)
09:24	clojurebot	"([protocol x]); Returns true if x satisfies the protocol"
09:24	budai	gfredericks: thanks :)
09:25	mungojelly	crocket: the ground reality for clojure is the jvm, or for clojurescript javascript, it doesn't help you dig below there. because you really really shouldn't for almost every purpose.
09:26	crocket	'almost'.
09:26	crocket	For writing kernel, you should.
09:26	crocket	For writing system libraries, you should.
09:26	crocket	That's not 'almost'.
09:26	gfredericks	well the answer for clojure will be the same as whatever platform you're on, generally
09:26	mungojelly	write just the performance sensitive parts in c and expose them as a library. it's not ideal but that's what everyone does.
09:27	gfredericks	so by deciding to use clojure on platform X you're agreeing to whatever restrictions platform X has in that category
09:27	crocket	I'd like to see a natively compiled variant of clojure.
09:27	crocket	NativeClojure, maybe.
09:27	crocket	The platforms are x86 and so on.
09:28	crocket	It should have built-in garbage collection.
09:28	mungojelly	clojure as a language is tied closely to the semantics of the jvm and indeed to the java libraries
09:28	crocket	So, I said 'variant'.
09:28	crocket	Or, a new langauge heavily inspired by clojure.
09:28	gfredericks	mungojelly: that's not true, cljs and clj-clr are both things
09:29	mungojelly	gfredericks: i've been wondering, how much code actually works across all of them?
09:29	wasamasa	not much
09:29	gfredericks	mungojelly: more and more, thanks to cljc
09:29	mungojelly	it seems like in practice things are mostly for one platform or another, but i don't have a sense for the details
09:29	gfredericks	except for the clj-clr part but only because nobody uses it
09:29	wasamasa	yup
09:30	crocket	cljs is terrific except tooling.
09:30	crocket	gfredericks, Is it possible to create a single source folder for both clojure and clojurescript?
09:31	gfredericks	crocket: yes, reader conditionals is a new feature in clojure 1.7 for sharing the same files
09:31	gfredericks	e.g., test.check will soon have a mostly unified codebase that works on the jvm and cljs
09:31	crocket	gfredericks, Do the build tools facilitate using single source folder for multiple languages?
09:32	gfredericks	crocket: yep
09:32	crocket	I haven't read a tutorial that teaches how to do it yet.
09:32	mungojelly	do we have any libraries for generating c? oh there's this c-in-clj thing, how's this work
09:32	crocket	I started learning clojurescript a while ago
09:32	gfredericks	crocket: github.com/gfredericks/test.chuck does
09:33	crocket	Can a web app pull it off, too?
09:33	crocket	isomorphic source base for server and client.
09:33	gfredericks	you can certainly share source when that makes sense
09:33	gfredericks	e.g., if you want business logic shared on both ends then you can do that easily
09:34	crocket	What kind of build tools support that?
09:34	gfredericks	leiningen
09:34	crocket	lein-cljsbuild?
09:34	gfredericks	yep
09:34	gfredericks	see test.chuck linked above
09:34	crocket	I'm not sure how it's done, yet. I'll get there.
09:34	gfredericks	another portable lib: https://github.com/gfredericks/exact
09:35	crocket	gfredericks, Can you recommend the best clojurescript learning material?
09:35	crocket	Clojurescript: up and running is quite old.
09:35	crocket	I already know clojure.
09:35	gfredericks	crocket: I think the wiki on github is supposed to be decent
09:36	dnolen	mungojelly: re: code sharing, ClojureScript is easily the most significant .cljc project, some 7000 lines of shared code so the compiler can run on JVM or JS
09:37	crocket	gfredericks, It refers me to several tutorials.
09:37	crocket	They all overlap.
09:37	crocket	They all overlap largely
09:41	crocket	gfredericks, Did you read clojurescript: up and running?
09:45	crocket	Damn...
09:45	crocket	If clojure could be used to write kernels and operating systems, it would rule the world.
09:47	gfredericks	crocket: no; I've been using cljs for >3yrs now so have no idea what modern tutorials are like
09:48	crocket	God damn you
09:48	crocket	3 years
09:48	crocket	You should be a clojure expert by now.
09:49	crocket	gfredericks, Do you think dependent types can be introduced to clojure?
09:51	gfredericks	crocket: any static type system is a tough fit, as the language just wasn't designed with that in mind
09:52	crocket	Static typing and dependent typing might save big projects with many devs.
09:52	crocket	Haskell comes into mind.
09:52	crocket	If google is found today, it'd use haskell instead of C++.
09:52	crocket	Haskell wasn't mature enough when google was growing.
09:53	gfredericks	crocket: I've been seeing a lot of similar benefits from prismatic/schema + test.check
09:53	crocket	What do they do?
09:54	hyPiRion	crocket: Google uses mainly Java internally, actually.
09:54	crocket	Oh
09:54	crocket	They do the work of static typing.
09:55	emauton	That's not at all true, FWIW: the languages used there are mostly C++, Java, Python and Go, in roughly that order.
09:57	crocket	I'm not sure if clojure should be the langauge for writing AI infrastructures.
09:57	crocket	JVM
09:57	crocket	JVM deters me.
09:57	crocket	It's hungry of RAM.
09:58	emauton	RAM is cheap, please try to forget that.
09:58	crocket	RAM is not cheap
09:58	crocket	RAM is cheap for big companies
09:58	crocket	That kind of thinking only makes hardware manufacturers richer.
09:58	hyPiRion	emauton: re C++: Really? Has it changed the last 1.5 years, or have I only been in contact with the "higher level" infrastructure?
09:59	crocket	Compared to OCaml, JVM uses ungodly amounts of RAM.
09:59	emauton	hyPiRion: I guess the latter. I've been out for 1.5 years myself. :o)
09:59	crocket	Now, OCaml is quite performant.
10:00	crocket	emauton, If RAM was so cheap, why don't you run linux on JVM?
10:00	emauton	crocket: I'm sorry, I won't be engaging with this anymore.
10:00	crocket	Write kernel in java
10:00	emauton	J
10:01	sotojuan	o.O
10:02	crocket	I want to see C killed.
10:02	hyPiRion	emauton: hah, alright then, I stand corrected. I've only talked to some Chrome devs, and they said that most services was Java, only outliers like Chrome/"low level" infrastructure was C++.
10:04	crocket	People nowadays launch java processes in VMs because dev time is as expensive as or more expensive than hardwares.
10:04	crocket	That doesn't mean hardware is cheap.
10:05	crocket	If you're desining client applications, you'll realize that ordinary people do not have 64GB of RAM.
10:06	nooga	that's why you move logic to the "cloud"
10:07	nooga	it's called SaaS ;D
10:07	crocket	Well, if you are designing native GUI applications and system libraries, you don't have that kind of luxury.
10:07	crocket	Smartphones have 1-4GB of RAM.
10:09	crocket	So, the assumption is that you're a cloud app developer.
10:09	crocket	Then, RAM is cheap.
10:10	crocket	However, people still miss the experience of native GUI apps.
10:10	sotojuan	I think most people nowadays are.
10:10	crocket	web browsers are slower.
10:10	crocket	They are limited
10:10	crocket	sotojuan, That's because of web bubble.
10:11	visof	hi
10:12	visof	i have list and function and want to apply function of list per element but each result of invocation is the input for other?
10:13	visof	(defn foo [x] (* x x)), (foo x), (foo (foo x)), (foo (foo (foo x)))
10:13	visof	how can i do this?
10:14	emauton	visof: Sounds like you might want http://clojuredocs.org/clojure.core/iterate
10:18	emauton	,(take 4 (iterate (fn [x] (* x x)) 2))
10:18	clojurebot	(2 4 16 256)
10:57	jimmy---	If anyone's got a moment to critique a macro that's like defn, but produces a curried version of the function, I'd love feedback. Notes, questions, and usage supplied in the link. Many thanks! http://pastebin.com/mBLMtLkX
11:01	justin_smith	(-> args count (= 0)) => (zero? (count args))
11:07	justin_smith	actually no => (empty? args)
11:10	justin_smith	jimmy---: you don't need gensyms, because no symbols created in that let body are emitted - it's just transforming forms and using existing symbols, not emitting any new symbols
11:14	justin_smith	jimmy---: `(defn ~name ~args ~body) => (list 'defn name args body)
11:15	justin_smith	(list `~args `~body) => (list args body)
11:16	justin_smith	(cons 'defn (cons `~name (seq `~all-bodies))) => `(defn ~name ~@all-bodies)
11:19	lodin-	jimmy---: I don't know if it's good or bad, but I almost always prefer syntax quote over constructing the result manually, even if it's just (list args body).
11:19	justin_smith	lodin-: to me it just ends up looking like cargo cult macro making. Use syntax quote if it's more concise and clear, if it isn't don't use it.
11:20	lodin-	justin_smith: I use it precisely because I think it's clearer. :-)
11:20	jimmy---	justin_smith: re:gensyms: OK. I personally didn't see any way that I could clobber anything, but I've been wrong plenty of times before.
11:20	justin_smith	lodin-: there's no way (list `~args `~body) is clearer than (list args body)
11:21	justin_smith	jimmy---: no symbol you create ends up in the output form
11:21	lodin-	justin_smith: I mean of course `(~args ~body).
11:21	justin_smith	lodin-: OK, I was talking about the actual code
11:22	justin_smith	and even compared to `(~args ~body) I find (list args body) much more clear
11:22	lodin-	justin_smith: Interesting.
11:23	jimmy---	justin_smith: I haven't thought it through entirely, but isn't it possible to clobber something in the code to be transformed by the macro within something like a let within the macro?
11:24	lodin-	I use `() as a way to tell the reader (= me) that "this will (probably) end up in macroexpand". I don't use it if I plan to pick it apart and manipulate it further.
11:24	justin_smith	jimmy---: your macro does not transform any symbol that comes in, and it does not emit any symbol that isn't a: in clojure.core or b: in its input already
11:24	justin_smith	jimmy---: you can't possibly clobber within those constraints
11:25	justin_smith	lodin-: `() is valid both inside and outside macros
11:25	lodin-	justin_smith: Sure.
11:28	jimmy---	justin_smith: Sorry, I wasn't clear. I just meant in general when writing macros, but I guess the fact that gensyms exist answers my question.
11:30	lodin-	I also tend to write `([~@args] ~@body), and not care about which sequence type args happens to be. I think this is much clearer than e.g. (conj args body), which might sound weird, but if I were to highlight only the syntax quoted code in a macro (and in code-returning functions used in the macro), I get a pretty good picture of how the resulting code will look.
11:30	justin_smith	jimmy---: that's true, and for that reason if you use let or defn inside ` it will force you to use gensyms
11:32	jimmy---	justin_smith: Ahh, OK, I didn't know it was forced within `. Good to know.
11:33	lodin-	jimmy---: Another point: I think it is customary that body is a seq, e.g. (defmacro foo [stuff & body] ...). If it's not several statements, call it "expr" or something. This is just my experience from having looked at some macros.
11:33	justin_smith	it's essentially a side effect of ` ns-resolving every symbol, and you can't let-bind ns-qualified names
11:41	jimmy---	lodin-: OK, I'll move away from the name 'body' in my case then. Thanks.
11:41	jimmy---	justin_smith: Ahh, right, that makes sense then.
11:42	lodin-	jimmy---: Why not change to [... & body] and adjust accordingly?
11:56	jimmy---	lodin-: Hmm... I'm trying to work it out. I just wonder if someone were to then look at it, if they'd expect to be able to send arities themselves, and then there's a whole new problem.
11:56	lodin-	jimmy---: I don't follow.
11:59	jimmy---	lodin-: Now one just sends a single argument, expr. If they saw it takes [name args & body], they might try to supply their different arities as such: (defcurried f ([] "no args") ([x] "one arg") ([x y] "etc."))
12:00	jimmy---	lodin-: And then maybe expect (if there were gaps in the arities) for the currying to "just work."
12:00	lodin-	jimmy---: Maybe, but I don't find it likely, really.
12:01	lodin-	[name args & body] is not [name & fn-tails]. The args is outside the seq, but in your example the args are in the seq.
12:01	jimmy---	lodin-: I agree, the likelihood is extremely small as I expect the number of users who use this to be countable on one thumb. :)
12:01	lodin-	jimmy---: I wouldn't worry about it.
12:03	lodin-	It's not necessary to use & body either, since you can always just use (do ...), but I think it is more likely that your users assume that you can add a leading assert or prn without it (and end up being confused by the error message).
12:06	lodin-	jimmy---: What are you porting, btw?
12:07	jimmy---	lodin-: OK. Got it afloat with & body now. Good practice if nothing else.
12:08	jimmy---	lodin-: I was going through the functional parsers section of the Graham Hutton Haskell book.
12:10	jimmy---	lodin-: I was giving pixie-lang a whirl, saw it could read json, but not output it, and realized I didn't really know much about parsing and looked into that.
12:10	jimmy---	lodin-: But then I ended up using protocols instead, but am going back to the parsing stuff now because it seems useful.
12:23	justin_smith	jimmy---: why would you parse anything in order to generate json?
12:23	justin_smith	jimmy---: usually when generating json you have data structures already in your program that you want to emit
12:24	justin_smith	and there's no parsing in that, unless you are doing it the hard way, turning the structures into strings, parsing them again, and then making json out of that?
12:27	jimmy---	justin_smith: For a json-in, json-out program, it's not simply emitting.
12:28	justin_smith	OK, you already mentioned it had json reading, I guess I misunderstood
12:29	justin_smith	so, you realized it couldn't write json, so decided to implement both reading and writing?
12:32	jimmy---	justin_smith: I've only done the writing thus far, which was a breeze, and was all that I actually needed given the reading was provided. But parsers weren't covered in my school's curriculum, so I'm just looking to fill that void at this point.
12:36	justin_smith	ahh, got it
12:36	justin_smith	hopefully they at least covered FSMs
12:39	jimmy---	justin_smith: It was gone over pretty quickly when covering regex. So we saw them and the BNF notation, but didn't put it to code unless you count regex.
12:40	justin_smith	got it
12:47	kavkaz	I know this isn't #emacs, but do you guys have any idea how to change the color of the menu bar and the scroll bar?
12:48	triss	so is there any work in the pipeline to make it possible to have :pre and :post conditions emit custom error messages?
12:49	triss	I'd love to be able to embed Strings that described the problem encountered in the error thrown
12:51	hellofunk	kavkaz: what menu bar? what scoll bar? :)
12:52	kavkaz	hellofunk: one second, i'll send you a screenshot
12:52	hellofunk	kavkaz: i am jesting with you
12:52	kavkaz	haha
12:52	hellofunk	kavkaz: most emacs users (well many) do not use those features in emacs at all and have the GUI turned off
12:53	hellofunk	triss: the pre/post map already shows which pre/post expression failed, in its message
12:54	justin_smith	kavkaz: there's faces defined for the menu and scroll bar and tool bar that you can use to set foreground and background colors
12:55	triss	cheers hellofunk. I'd love to be able to provide a message like I do would with `assert`
12:55	triss	could make my library a lot more friendly
12:56	justin_smith	yeah, pre / post are very uninformative, I just do asserts instead, much more flexible in representation and in output
12:56	justin_smith	I mean it's an OK idea just not polished enough to be actually useful for me
12:56	justin_smith	also I can throw an assert into the middle of a let block, etc.
13:00	kavkaz	Ah thank justin_smith
13:00	kavkaz	thanks hellofunk, but I'll probably try first with my GUI version
13:01	justin_smith	kavkaz: my favorite idiom (assert (ok? input) (str "input was not ok: " (pr-str (select-keys input [:relevant :keys]))))
13:01	justin_smith	pr-str so that things containing strings and/or symbols will be readable
13:01	kavkaz	haha justin_smith did you mean triss
13:02	justin_smith	ahh, oops
13:02	justin_smith	got my channels crossed
13:02	kavkaz	Yes the assert thing changed the colors of my emacs haha
13:03	triss	pleased to know it bothers more than just me justin_smith
13:04	triss	Would it really be so hard to implement? Are there reasons it hasn't been?
13:04	kavkaz	,(assert (colors-ok? my-colors) (println "keep using emacs") (println "keep working on your .emacs file"))
13:04	clojurebot	#error {\n :cause "Wrong number of args (3) passed to: core/assert"\n :via\n [{:type clojure.lang.ArityException\n :message "Wrong number of args (3) passed to: core/assert"\n :at [clojure.lang.Compiler macroexpand1 "Compiler.java" 6797]}]\n :trace\n [[clojure.lang.Compiler macroexpand1 "Compiler.java" 6797]\n [clojure.lang.Compiler macroexpand "Compiler.java" 6853]\n [clojure.lang.Compiler ...
13:05	kavkaz	oh true
13:05	kavkaz	haha didn't do it right
13:05	justin_smith	kavkaz: also, assert messages don't work like that
13:25	justin_smith	,(assert false (str "this guy, " 'kavkaz " does not use assert."))
13:25	clojurebot	#error {\n :cause "Assert failed: this guy, kavkaz does not use assert.\nfalse"\n :via\n [{:type java.lang.AssertionError\n :message "Assert failed: this guy, kavkaz does not use assert.\nfalse"\n :at [sandbox$eval25 invokeStatic "NO_SOURCE_FILE" 0]}]\n :trace\n [[sandbox$eval25 invokeStatic "NO_SOURCE_FILE" 0]\n [sandbox$eval25 invoke "NO_SOURCE_FILE" -1]\n [clojure.lang.Compiler eval "Comp...
15:06	roelof	Can I take care that 2 expressions are executed after a if then is true. And if so, how can I do this ?
15:07	justin_smith	roelof: do
15:07	justin_smith	roelof: if your if would be only one branch, use when
15:08	justin_smith	,(if true (do (print 'a) (print 'b)) 'c)
15:08	clojurebot	ab
15:08	justin_smith	,(when true (print 'a) (print 'b))
15:08	clojurebot	ab
15:09	roelof	oke, I have this http://lpaste.net/141379 and after the W , I have to update another variable thorX with 1
15:10	roelof	and after the E I have to decrease the same variable with 1
15:11	justin_smith	roelof: that looks more like a case for cond
15:11	justin_smith	,(cond (> 0 1) "W" (< 0 1) "E" :else "")
15:11	clojurebot	"E"
15:11	justin_smith	I think that's what you want
15:13	roelof	justin_smith: no, what I want is something like this if var1 < var2 then W ; var1 = var1 + 1 else
15:13	roelof	""
15:13	oddcully	,(let [thor-x 5 light-x 2] (get {-1 "W" 0 "" 1 "E"} (compare thor-x light-x)))
15:13	clojurebot	"E"
15:14	roelof	oddcully: is thor-x there updated ?
15:14	justin_smith	roelof: what is "+ 1"
15:15	roelof	+1 means that var1 is increased by 1
15:15	justin_smith	oh, you aren't using clojure = there, OK
15:15	roelof	sorry
15:17	justin_smith	(let [var1 0 var2 1 [result var1] (case (> var1 var2) ["W" (inc var1)] (< var1 var2) ["E" var1] :else ["" var1])] ... (code using var1 and result)) ; something like this?
15:18	justin_smith	you can easily make a new binding for var1, actually changing it is a whole other mess
15:19	roelof	justin_smith: I think so . I have to try it out
15:26	roelof	hmm, still errors on this code : Exception in thread "main" java.lang.RuntimeException: Unmatched delimiter: ), compiling:(Player.clj:21:42)
15:27	justin_smith	OK, so you have too many close parens somewhere?
15:29	roelof	justin_smith: I think so, Clojure is more difficult then I thought after reading 4 chapters of Living Clojure
15:31	justin_smith	roelof: it can help to have an editor which has paren highlighting, or auto indent, or paren-colorizing
15:32	roelof	justin_smith: the challenge site has one but still I do not see it. I have deleted all the ) after the [] except the last one and still the same error
15:32	justin_smith	can you share the updated code?
15:33	roelof	justin_smith: yes, here you have : http://lpaste.net/141381
15:35	justin_smith	roelof: for starters, on line 10 you should be providing a binding vector for the results of the case on line 10
15:35	justin_smith	roelof: second problem, there is nothing in your code that will actually propagate the new bindings when the while does its next iteration
15:35	justin_smith	you can fix this by changing while to loop, and passing the new bindings to recur
15:37	roelof	oke, the W must be in the variable directionX or directionY. If I read the code right thor-x and thor-y are already updated
15:37	justin_smith	roelof: nothing can update in that code
15:37	justin_smith	it's impossible, there is no mechanism by which this would occur
15:38	roelof	pff, I think Clojure is not for me. Im struggeling the whole day with this problem
15:38	justin_smith	you can shadow bindings with new bindings, but by the time the while does its next loop, the old bindings don't even exist any more
15:39	justin_smith	roelof: there's one root misunderstanding going on for you here, and once you sort that out everything else comes from understanding the consequences of it
15:39	justin_smith	roelof: clojure bindings do not change, ever. They can be shadowed, or replaced in a new iteration, but nothing changes them.
15:40	justin_smith	roelof: so you need mechanisms to propagate new bindings to their context
15:40	justin_smith	these include loop/recur, recursive functions, or shadowing within a single let block
15:40	roelof	yes, I read that So I have to use things like reset! ?
15:40	justin_smith	no
15:40	justin_smith	roelof: the syntax problem is that you don't close the let binding vector
15:41	justin_smith	the reason it's complaining about an unexpected ")" is because it needs a "]" first
15:42	justin_smith	in order to rebind thor-x and thor-y, you need to rewrite the case call so that every result returns thor-x, thor-y, and the direction string
15:42	justin_smith	currently you aren't even using the result of the case
15:44	roelof	oke, back to the books then
15:46	justin_smith	,(loop [x 0 y 0 iterations 0] (let [new-x (+ x (dec (rand-int 3))) new-y (+ y (dec (rand-int 3)))] (if (= new-x new-y 10) iterations (recur new-x new-y (inc iterations))))
15:46	clojurebot	#<RuntimeException java.lang.RuntimeException: EOF while reading>
15:47	justin_smith	,(loop [x 0 y 0 iterations 0] (let [new-x (+ x (dec (rand-int 3))) new-y (+ y (dec (rand-int 3)))] (if (= new-x new-y 10) iterations (recur new-x new-y (inc iterations)))))
15:47	clojurebot	Execution Timed Out
15:47	justin_smith	,(loop [x 0 y 0 iterations 0] (let [new-x (+ x (dec (rand-int 3))) new-y (+ y (dec (rand-int 3)))] (if (= new-x new-y 10) iterations (recur new-x new-y (inc iterations)))))
15:47	clojurebot	Execution Timed Out
15:47	justin_smith	that immediatly returns a number (about 250k) on my box
15:47	justin_smith	,(loop [x 0 y 0 iterations 0] (let [new-x (+ x (dec (rand-int 3))) new-y (+ y (dec (rand-int 3)))] (if (= new-x new-y 5) iterations (recur new-x new-y (inc iterations)))))
15:47	clojurebot	17
15:48	justin_smith	roelof: that's a random walk that stops when x and y are both 5
15:48	justin_smith	you should be able to use the same basic structure as above (modified for your own logic of course)
15:48	roelof	justin_smith: thanks
15:49	justin_smith	oh wow, I guess my first try with 10x10 was lucky
15:49	justin_smith	the second run locally is taking forever...
15:50	roelof	oops, not good
15:50	justin_smith	execution time of a random walk to a determined point is very unpredictable :P d'oh
15:51	roelof	I think you are right here
15:52	justin_smith	I wonder what the minimum coordinate distance from 0 is where integer overflow is more likely than hitting the target
15:52	roelof	but im going to bed. it's late here. and thanks for the explantion and patience with me
15:56	justin_smith	roelof: no problem, thank you for your patience as well, I know it's not always easy
16:01	roelof	nope, maybe if I look at it with a fresh look there will be a aha moment
16:01	roelof	till now I find it all very confusing
16:02	roelof	maybe wait for the new brave and true and try to learn from that. I did now use living clojure and the click is not there
16:03	justin_smith	In the long run, immutability makes things much less confusing. Clojure isn't a harder way to do things, just a different one. Give it time to sink in, like a new language.
16:11	sobel	I think immutable data has made my programming life simpler
16:13	roelof	for me as beginner at this moment not. Like I said earlier I m the whole day busy with this challenge which seems to be easy
16:16	roelof	maybe someone knows a good beginners book with a lot of exercises
16:17	justin_smith	roelof: this task you picked would be easier for you right now if you didn't know how to program already, the mistakes you are making are basically caused by assumptions about programming languages that clojure doesn't follow
16:19	jakesyl	#join facebook
16:19	roelof	justin_smith: that can also be a reason
16:21	roelof	and I see that loops and recurr are not explained in the living clojure book
16:22	roelof	so I think I wait for the new brave and true and hopefully that book will explain that
16:23	roelof	in this example there is also no recur ;; a var to be used for its side effects (def a (atom 10)) ;; #'user/a (while (pos? @a) (do (println @a) (swap! a dec))) ;; 10 ;; 9 ;; 8 ;; 7 ;; 6 ;; 5 ;; 4 ;; 3 ;; 2 ;; 1 ;;=> nil
16:23	amalloy	justin_smith: another way of writing the random walk that i think is interesting:
16:23	amalloy	,(count (take-while (complement #{[3 3]}) (reductions (partial map +) [0 0] (repeatedly #(repeatedly 2 (fn [] (dec (rand-int 3))))))))
16:23	clojurebot	47873
16:24	roelof	but im now really goto bed. Good night all
16:27	justin_smith	amalloy: nice, you could do that one with iterate too I think
16:28	amalloy	yeah, but the lambda you give to iterate is bigger, since it needs the + and the randomness. i like keeping them separate, and this almost survives with no lambdas
16:46	justin_smith	Now I am asking myself why I committed myself to do a live performance using software that wasn't done yet. I had my code all ready to go and see at the last stretch that my raspberry pi (which was going to run this synth code) doesn't boot. Now trying to reinstall and crossing my fingers this is not a hardware problem...
17:45	mungojelly	have any of you tried funding your programs chits and then charging them for resources? i'm sick of my programs getting a free ride :p
17:53	mungojelly	for disk space i guess i'm going to auction blocks of database inserts or something, that's easy to quantify, i could even charge them by the byte. i'm less sure how to charge for processing, maybe auction off slices of time and warn and terminate!?
17:55	justin_smith	mungojelly: just like in macroeconomics, the ideal is 100% resource usage because savings is meaningless under inflationary pressure. I want all my CPUs at 100% - and then I optimize so that more work is getting done.
17:56	justin_smith	introducing a systemic pressure to prevent resource usage is counterproductive if you have any task you are undertaking.
17:57	mungojelly	justin_smith: you always decide manually about specific resources, though, eh? what i'm saying is i want the resources to be maxed out and distributed, but instead of saying who specific resources go to i want just to say which things are important without specifying what resources that translates into
18:00	justin_smith	mungojelly: if your app is complex enough to have more than one task workflow, you can use a system like onyx which allows task prioritization, but most everything I've made before my current onyx process has client requests, and then a set of unconditional tasks which are needed to fulfil each request
18:02	mungojelly	justin_smith: what i'm making is evolving processes, they reproduce when they can so there's always (more than) the maximum of them, so i can't just always say yes to them i have to have some way of dumping/ignoring low priority (potential) tasks
18:15	mungojelly	today i managed to get "lein run" to run the same thing i got working in the repl, but it was more complicated than i expected. :/ is there something i should read or watch about leiningen that'll make things clearer?
18:15	justin_smith	mungojelly: no top level side effects
18:15	justin_smith	mungojelly: that means don't call def with args that alter state
18:16	justin_smith	once you are following that rule, it's easy
18:16	justin_smith	all stateful initialization should be done explicitly inside -main, or by some function called by -main
18:17	mungojelly	i learned this -main thing and also i learned to say :main somewhere else pointing at the namespace with -main in it
18:17	mungojelly	but there's clearly a zillion other things i'm missing, i need leiningen 101
18:17	justin_smith	eh
18:18	justin_smith	leiningen is mostly declarative, once you learn what the valid keys are that's usually it
19:54	cammellos	join haskell
20:34	hlolli	,(defn print-hello [] (prn "hello-atom"))
20:34	clojurebot	#'sandbox/print-hello
20:34	hlolli	,(print-hello)
20:34	clojurebot	"hello-atom"\n
20:35	justin_smith	hlolli: so I was going to be performing using a csound thing tonight, but my raspberry pi broke at the wrong moment
20:35	hlolli	,(def atomic-eval (atom {:eval #'print-hello}))
20:35	clojurebot	#'sandbox/atomic-eval
20:36	hlolli	ok, I tried using csound on the raspberrym it's very unstable. Very slow for sure.
20:36	hlolli	Haven't tried the new one, is it compleatly broken or just a bug?
20:36	justin_smith	the device is refusing to boot
20:36	justin_smith	I think some hardware is bust
20:37	hlolli	,(eval (:eval @atomic-eval))
20:37	clojurebot	#'sandbox/print-hello
20:37	hlolli	why didn't that work?
20:37	justin_smith	hlolli: you aren't calling the var
20:37	justin_smith	hlolli: you are just returning it
20:38	justin_smith	,((:eval @atomic-eval))
20:38	clojurebot	"hello-atom"\n
20:38	justin_smith	hlolli: eval isn't for calling functions, it is for compiling them
20:38	hlolli	wtf, ok, return it then eval. ok I see
20:38	justin_smith	when you give it something that doesn't need any resolution or compilation, it just gives you the thing
20:38	justin_smith	hlolli: no, no eval
20:38	justin_smith	eval is for compiling, the thing you have is already compiled
20:39	hlolli	ok, Im getting the grips of this difference of compile time and run time.
20:39	justin_smith	hlolli: every form you type into the repl is implicitly evaled already, and having to use eval otherwise is usually a sign you are doing something wrong, unless you are writing a compiler
20:40	hlolli	ok ok
20:40	justin_smith	the repl is a loop, it reads forms, compiles them, then prints the result, then loops
20:40	justin_smith	REPL
20:40	hlolli	I just would not have guessed on double parenthesis
20:40	justin_smith	hlolli: parenthesis are the syntax for calling things
20:40	hlolli	ok ok
20:41	justin_smith	if you have a function, and want to call it, you need to wrap it in parens. If something returns a function and you want to call it immediately, you need double parens
20:41	justin_smith	if you had a function returning a function returning a function, triple parens would be the thing you want
20:42	mungojelly	,(let [x (fn [] (fn [] (fn [] "hi")))] (((x))))
20:43	clojurebot	"hi"
20:43	hlolli	haha ok, funny how thinking about some language feature before knowing that it's a feature, that's how I usually learn best, to see it in practice.
20:43	hlolli	triple!
20:44	rhg135	The factories of factories are useful
20:45	gfredericks	,(let [f (nth (iterate constantly 42) 10)] ((((((((((f)))))))))))
20:45	clojurebot	42
20:46	hlolli	10 parenthesis, winner
20:48	gfredericks	I wonder what the upper limit on that is
20:48	domgetter	And that was the last time we saw gfredericks alive...
20:49	hlolli	jvm nuke
22:30	rritoch	Is there any way to create a new class that extends another class overriding some methods without using a gen class? I've been trying to get away from gen-class dependence but for this issue I can't see a way around it.
22:48	domgetter	If I have a clojurescript app and I want to maintain a list of stuff that's updating, like a chatlog, is it better to use an atom or one of the immutable persistent data structures?
22:54	namra	domgetter: i think a chatlog can become quite large, and immutable means higher memory requirements. using an atom in this case would you save memory, but don't know if it would also be faster, something to test. and because of clojure easy and safe way to actually work with atoms, why not use it.
22:56	namra	cljs not clojure ^^
22:56	domgetter	namra: That's sensible. I'll try to get to a point where I would understand how to test that.
22:59	namra	a simple way i can think of is using included time fns near the code that updates i.e. the chatlog
23:01	namra	there's even a time macro
23:01	namra	(doc time)
23:01	clojurebot	"([expr]); Evaluates expr and prints the time it took. Returns the value of expr."
23:01	namra	.(doc time)
23:07	amalloy	"should i use an atom or a persistent data structure" seems like the wrong question to me: almost the only sensible thing to put in an atom is a persistent data structure
23:23	python476	hi there
23:23	python476	I'm having trouble converting this Path path = FileSystems.getDefault().getPath("logs", "access.log");
23:24	python476	Started with this (.. FileSystems getDefault), ok, (.. FileSystems getDefault (getPath "/var")) fails
23:25	python476	(and btw, I'm not trying to be idiomatic, it was about learning java interop)
23:36	Sauken	Hello!
23:36	mal_	hola
23:37	amalloy	python476: http://stackoverflow.com/q/5638541/625403
23:37	python476	Apparently one has to ... (Paths/get "/" (into-array String ["bar" "baz"])) sometimes
23:37	python476	makes me cry all inside
23:37	python476	amalloy: heh, was just reading this.
23:37	Sauken	I've got a question. So I made a random letter generator in C++, and I made it write 10,000 random capital letters from A-Z
23:38	Sauken	How do I look for my name inside of those letters?
23:39	python476	unless you (Paths/get (URI. "file:///var/log")) then interop lands on its feet
23:41	python476	oh and you were the author of the final answer, how convenient