#clojure – 2015-09-30

2015-09-30

00:16	sm0ke	,`memoize
00:16	clojurebot	clojure.core/memoize
00:16	sm0ke	shouldbe in cljs.core
02:25	amalloy	akkad: (a) why do you need a bigger stack, really; (b) why is it a fight? just set the appropriate jvm option
03:24	Guest21161	i'm looking for a clojure library which i can use to navigate websites: fill in forms, login, download a file etc
03:30	algernon	enlive sounds like something you could use for that.
03:56	nowprovision	enlive works well but won't handle any on page javascript
03:56	nowprovision	personally I prefer phathomjs for this sort of stuff
03:57	nowprovision	or actually even node.js with cheerio over enlive for extraction but for interaction phanthom js, and enlive as an alternative for building web pages (css path substitutions)
05:12	marshzor	if I have a seq that I'm fairly certain will always contain one element, is there a good way to extract that element? Currently I'm using (first myseq)
05:13	marshzor	I have a list of ui elements, each with an id. I get an event saying element with id=foo was clicked. so I get (filter #(= (:id event) (:id %)) ui-elements)
05:14	hyPiRion	marshzor: you can do (let [[elem] myseq] elem) if you need to bind the result
05:14	marshzor	interesting, let me give that a try
05:14	hyPiRion	er, I mean (let [[elem] myseq] my-code)
05:15	marshzor	mhm I knew what you meant
05:16	marshzor	definitely seems more sane than what I had, although I'm not sure how this would act if the seq actually did contain more than one element
05:16	marshzor	,(let [[elem] '(1)] elem)
05:17	clojurebot	1
05:17	marshzor	,(let [[elem] '(1 2)] elem)
05:17	clojurebot	1
05:17	marshzor	so is it just sugar for first?
05:17	hyPiRion	yeah
05:17	marshzor	ah okay
05:17	hyPiRion	,(macroexpand '(let [[a] b] a))
05:17	clojurebot	(let* [vec__77 b a (clojure.core/nth vec__77 0 nil)] a)
05:32	fehrenbach	,(source first)
05:32	clojurebot	Source not found\n
06:00	visof	hi guys
06:01	visof	how can i declare function with two options artgument in defprotocol?
06:02	visof	(defprotocol Hello (foo [a]) (foo [x y])) ? and handle it (defn foo ([x] "Hello") ([x y] "hello hello")) ?
06:02	visof	is this correct?
06:10	bendlas	apparently build.clojure.org is down and this prevents dependency resolution hence startup of projects depending on datomic
07:09	visof	is there any tool which can take file.clj and autoindent it?
07:53	mavbozo	visof, https://github.com/weavejester/cljfmt
08:24	nowprovision	it's not perfect quite perfect, vim clojure plugin disasgrees with a small indent rule (which I think clojure style guidelines agrees with vim clojure)
08:24	nowprovision	but at least it diffs rather than forces the hand like gofmt (and vim-go)
08:33	nowprovision	visof, (defprotocol P (foo [this] [this arg2]))
08:33	nowprovision	visof, (defrecord R [] P (foo [this] this) (foo [this arg2] arg2))
08:52	marshzor	does anyone know a good way to evaluate a seq of bools? I want to know if they are all true
08:53	schmir	,(doc every?)
08:53	clojurebot	"([pred coll]); Returns true if (pred x) is logical true for every x in coll, else false."
08:54	tdammers	,(all [true true true true])
08:54	clojurebot	#error {\n :cause "Unable to resolve symbol: all in this context"\n :via\n [{:type clojure.lang.Compiler$CompilerException\n :message "java.lang.RuntimeException: Unable to resolve symbol: all in this context, compiling:(NO_SOURCE_PATH:0:0)"\n :at [clojure.lang.Compiler analyze "Compiler.java" 6704]}\n {:type java.lang.RuntimeException\n :message "Unable to resolve symbol: all in this conte...
08:54	tdammers	pff
08:54	tdammers	,(and [true true true true])
08:54	clojurebot	[true true true true]
08:54	tdammers	,(apply and [true true true true])
08:54	clojurebot	#error {\n :cause "Can't take value of a macro: #'clojure.core/and"\n :via\n [{:type clojure.lang.Compiler$CompilerException\n :message "java.lang.RuntimeException: Can't take value of a macro: #'clojure.core/and, compiling:(NO_SOURCE_PATH:0:0)"\n :at [clojure.lang.Compiler analyze "Compiler.java" 6704]}\n {:type java.lang.RuntimeException\n :message "Can't take value of a macro: #'clojure....
08:54	tdammers	that didn't go as expected
08:55	marshzor	yep, that's what I was looking for schmir, ty
09:08	dzhus`	If I update dependencies in my project.clj, can I get CIDER to pick the up in the classpath without killing the REPL buffer and jacking in from scratch?
09:27	schmir	dzhus`: there's vinyasa that may help a bit (at least with new dependencies). upgrading probably doesn't work though (just guessing)
09:37	ionthas	Is there any way to apply a function to each vector inside a vector? (def v3 [[10 [1 2]] [30 [4 5]]]) I would like to apply a custom function to each vector. Using (apply) results on a "Wrong number of args exception".
09:37	dzhus`	ionthas: I believe you might use something from clojure.walk
09:38	ionthas	I will take a look, thanks!
09:51	oddcully	ionthas: sounds like map
09:53	ionthas	oddcully: I have done a loop/recur through all my vector and I apply the function to each vector. I supose there's a more idiomatic way to do it. :/
09:55	oddcully	,(map (fn [[_ v]] (apply + v)) [[10 [1 2]] [30 [4 5]]])
09:55	nowprovision	yes clojure.walk if they are at unpredicable depths
09:55	clojurebot	(3 9)
09:55	oddcully	i don't know, what you are after
10:16	devn	,(require '[clojure.walk :as walk])
10:16	clojurebot	nil
10:20	devn	was going to drop an example, but yeah, might make more sense to hear what you're looking for
10:20	devn	since oddcully's example will do what you first described
10:21	justin_smith	ionthas: (for [subcoll coll] (apply f subcoll)) might do what you want?
10:24	ionthas	nvm folks I already solved the problem with a solution similar to the one provided for justin_smit. Thank your for your ideas.
10:24	devn	,(for [subcolls :)
10:24	clojurebot	#<RuntimeException java.lang.RuntimeException: Invalid token: :>
10:24	devn	derp
10:30	dzhus`	I believe that using components library implies that I need to have a "main" function in my app that will actually start the components?
10:31	dzhus`	But I do `lein ring uberjar` to build my app which only requires ring routes to be defined, can I somehow tweak the main function it generates for me to include components startup?
10:33	justin_smith	dzhus`: do component startup in the function that returns your handler
10:39	dzhus`	justin_smith: I don't think that I have one. I have a defintion of my routes and handlers but no function that "returns" them
10:45	justin_smith	dzhus`: I forget if lein ring has a mechanism for this directly... but if nothing else you should be able to define the handler in terms of a delay (so that it only runs when the handler is to be used, and only runs on first usage)
10:46	justin_smith	(def initialized (delay (startup-system))) (def handler (fn [request] @initialized (real-handler request))
10:47	justin_smith	the only problem with this is it makes the very first request to the newly started server wait for system init
10:48	justin_smith	dzhus`: LOL ignore the above hack - just look at the README here - use :init https://github.com/weavejester/lein-ring#general-options
10:48	dzhus`	duh, should have looked there
10:48	dzhus`	thanks
10:49	justin_smith	heh, np, but the delay trick is generally useful if you need to hack in init in something that doesn't provide the option :)
12:21	hlolli	who's would know of cleaver way to make a function that finds the avarage of two numbers in a list and put into new list, so I could get: [0.5 1.5 2.5 3.5] from [1 3] and [0 1 2 3] from [0 2]
12:23	jeremyheiler	hlolli: use something like (map avg (partition ...))
12:23	jeremyheiler	and then flatten it
12:24	justin_smith	jeremyheiler: or you could just use mapcat instead of map
12:24	justin_smith	flatten is pretty terrible
12:24	hlolli	so far I have (vec (flatten (for [[x y] (partition 2 1 on-s)]
12:24	hlolli	(list (- y (/ (+ y x) 2)) (+ y (/ (+ y x) 2))))))
12:25	jeremyheiler	justin_smith: i meant the general idea of flatten
12:25	jeremyheiler	justin_smith: trying not give the whole answer away ;-)
12:25	justin_smith	jeremyheiler: OK, well mapcat does that all in one go with your mapping
12:25	jeremyheiler	yes, that' better
12:25	hlolli	well, I use flatten shamelessly, damn.
12:25	blake_	I guess you'd have to.
12:26	blake_	I mean, if you had any shame...
12:26	justin_smith	hlolli: flatten has a few issues - it breaks things that could otherwise work with collections as arguments, and it can do unexpected things for some inputs
12:27	blake_	And speaking of shame, I have a realized LazySeq that refuses to be iterated over. What's up with that?
12:27	hlolli	ok, never ran into any problems so far. Its just that some functions always return extra parenthesis. For example everyting after the & sign
12:28	hlolli	I know its for good reason, but I tend to flatten it or unqote splice it.
12:28	blake_	like, (map #(println %) my-lazy-seq) produces nothing.
12:28	hlolli	tried doall ?
12:28	blake_	Yep.
12:28	hlolli	and take?
12:28	blake_	take?
12:29	hlolli	(take n coll)
12:29	blake_	huh, no...
12:29	blake_	I didn't know that was a thing. I'm still trying to figure out how this can happen.
12:30	blake_	Nope, (take n coll) doesn't work either.
12:30	blake_	Count returns the right number of items.
12:31	blake_	First returns the first item. Last returns the last item. Map produces nothing. For produces nothing.
12:31	hlolli	,(take 5 (map #(conj "hoho" %) (cycle "1")))
12:31	clojurebot	#<ClassCastException java.lang.ClassCastException: java.lang.String cannot be cast to clojure.lang.IPersistentCollection>
12:32	hlolli	,(take 5 (map #(conj "hoho" %) [(cycle "1")]))
12:32	clojurebot	#<ClassCastException java.lang.ClassCastException: java.lang.String cannot be cast to clojure.lang.IPersistentCollection>
12:33	hlolli	,(take 5 (map #(conj "hoho" %) (cycle ["1"])]))
12:33	clojurebot	#<RuntimeException java.lang.RuntimeException: Unmatched delimiter: ]>
12:33	hlolli	last time :)
12:33	blake_	heh
12:33	hlolli	,(take 5 (map #(conj "hoho" %) (cycle ["1"])))
12:33	clojurebot	#<ClassCastException java.lang.ClassCastException: java.lang.String cannot be cast to clojure.lang.IPersistentCollection>
12:33	hlolli	damn, fukkit, I should do it in my own repl first.
12:34	hlolli	,(take 5 (map #(conj [1] %) (cycle [2 3])))
12:34	clojurebot	([1 2] [1 3] [1 2] [1 3] [1 2])
12:35	hlolli	,(type (take 10 (cycle "a")))
12:35	clojurebot	clojure.lang.LazySeq
12:35	hlolli	cycle is a lazy seq....
12:36	hlolli	are you using the lazy-seq function?
12:36	blake_	Nope. I got this LazySeq out of a map.
12:37	blake_	It responds to no iterative requests from what I can tell.
12:37	blake_	If I say (into #{} my-lazy-seq) I get nothing back.
12:38	blake_	wait..
12:39	hlolli	well, you may need to map/apply/reduce it.
12:39	blake_	It does response to (into #{}).
12:39	blake_	er respond to
12:39	blake_	I'm trying to map it and it acts as though it's empty
12:39	blake_	While claiming to have 2 items, showing me the first, last...
12:40	hlolli	yes, it doednt calcualte the lazy sequence. Is it infinite?
12:40	blake_	Nope, it's very finite. One or two items. I mean, eventually, it could be several dozen. But well short of infinity. =P
12:41	hlolli	how about (into #{} (doall my-lazy-seq)) or (map #(into #{} %) my-lazy-seq)
12:42	blake_	Newp.
12:42	blake_	Into [] and #{} do make "copies" but they won't iterate either.
12:42	blake_	This has to be something burningly stupid.
12:43	blake_	If first, last and rest work on it, how can map possibly not?
12:46	hlolli	Im very surprised, there is something you are overseeing, is I would see this I could maybe help better.
12:47	blake_	https://www.refheap.com/110118
12:47	blake_	Lotsa printlns in there.
12:47	hlolli	have you tried simply (apply hash-map lazy-seq)
12:50	blake_	That seems to wrap things up in another layer. Still doesn't iterate, though.
12:50	xeqi	blake_: for and map are lazy, those printlns never get realized and thus never print
12:51	blake_	xeqi: Hmm. OK. I have to think about that because they weren't originally printlns.
12:55	blake_	OK. So...I was using map for side-effects. That's gotta be the problem.
12:56	justin_smith	blake_: didn't someone ask about doall?
12:56	blake_	justin_smith: Yeah, and I had doall.
12:56	justin_smith	in the wrong place then?
12:57	justin_smith	blake_: in 1.7 you can use run! instead of map (if you don't need the return value) - same arg usage
12:57	blake_	justin_smith: Yeah. And I was testing with (map (println... which I shouldn't do. And then following it up with a map to produce side-effects.
12:57	justin_smith	blake_: ahh, OK
12:58	blake_	justin_smith: The issue (mentally) is that I'm thinking in pure functions--but underneath I've got a Java object.
12:58	blake_	When I transition between them, I have...issues.
14:08	sven42	Hi - is there any way to call elisp functions from the clojure cider repl? I want to (read-string "prompt:")
14:14	mgaare	sven42: eval-last-sexp
14:23	triss	so how would you chaps go about parsing blobs of EDN out of a Markdown file?
14:23	triss	specificly keywords and maps
14:24	triss	I really want to associate the blobs of EDN with the most recent header in the markdown some how too.
14:39	TimMc	triss: Arbitrary EDN would be hard to spot, yeah.
14:39	TimMc	For example, this sentence contains 9 valid EDN blobs.
14:40	triss	yup. but I'm just after keywords and maps
14:41	triss	so this sentance only :contains only {2 "EDN blobs"}
14:41	triss	or is that 5 I guess....
14:41	triss	think I'm gonna just reg-ex for them and then parse
14:42	TimMc	I'd look for #"(^\|\s)[:{]" a pushback reader try feeding those into read.
14:42	TimMc	*in a
14:42	triss	do any of the clojure based markdown libs give you nice structured output?
14:42	triss	TimMc: precisley what i'm thinking!
14:43	numberten	will throwing an exception short circuit a let binding in clojure?
14:43	TimMc	Are you going to be running your documentation through tests? :-D
14:44	TimMc	numberten: Like in (let [a (/ 1 0) b (println "b")] ...), you're wondering if b's value is computed?
14:44	numberten	(let [a 1 b (throw (Exception. "bad")) (c (foo b))] (etc))
14:44	numberten	seems dangerous, if the entire function doesn't propagate the exception
14:45	numberten	TimMc: yeah that
14:45	TimMc	Well, the exception stops execution of the entire let expression, so yeah, further bindings are not evaluated -- nor the body.
14:51	numberten	thanks
15:25	amalloy	so guys, i realized the other day that `(~x ~@xs) is fewer characters than (cons x xs). alert the press, we don't need cons anymore!
15:26	oddcully	fetch me my codecolf putter
15:29	fuuduCoder	smetimes verbosity matters :-P
15:49	ghadishayban	oh man I miss clojure.
15:49	ghadishayban	been doing python and Spark lately
15:49	ghadishayban	Languages Matter.
15:50	aaelony	ghadishayban: are you doing Spark from Clojure?
15:51	aaelony	ghadishayban: also, is it reasonable to try to do python via pixie-lang with clojure syntax ?
16:03	neoncontrails	aaelony: your suggestion kind of reminds me of a project I've been mulling over. How hard do you think would it be to implement a Python interpreter in Clojure?
16:05	aaelony	neoncontrails: wouldn't it be great to use libs like scikit-learn from a clojure syntax?
16:05	neoncontrails	It seems like one of those projects which would be easy to set up, but possibly hard to get right. Lots of edge cases
16:05	aaelony	certainly
16:09	ghadishayban	aaelony: not from clojure. Team isn't really Lisp / FP oriented
16:09	neoncont_	Sorry, battery died. Can you think of any technical hurdles that would make interpreting scipy from Clojure painfully difficult?
16:10	neoncont_	If I'm not mistaken, part of the magic of scikit comes from a C-based implementation
16:37	xemdetia	neoncont_, it seems faster just to get jython and clojure to talk :)
17:03	aaelony	ghadishayban: I think both https://github.com/gorillalabs/sparkling and https://github.com/yieldbot/flambo offer Spark use from Clojure
17:06	aaelony	neoncont_: not sure, but this talk on pixie got me thinking these crazy-like ideas about using python libs from clojure syntax... https://www.youtube.com/watch?v=1AjhFZVfB9c
17:23	TEttinger	aaelony: ghadishayban left, I wanted to mention that I encountered some pitfalls trying to get some spark concepts to carry over to clojure
17:24	TEttinger	aaelony: it is neat how clojure seems to be revitalizing lisp dev a bit, that and racket
17:24	TEttinger	people seem to be more willing to make new languages that are unashamed to use parentheses
17:27	aaelony	TEttinger: I agree. Speaking for myself, I find that it is easier to come back to a project and figure out what is going on just by looking at each function involved. In other languages, it's unclear what an object is doing under the hood and what is being changed inadvertently or mysteriously. Just my 2 cents.
17:28	justin_smith	TEttinger: you can't really use python libs from pixie though.
17:28	justin_smith	TEttinger: it uses rpython to compile a vm that does not contain the python runtime - the python runtime would be a separate (and I think incompatible) target for rpython. Pixie doesn't load python libs.
17:29	TEttinger	TEttinger is not who you mean
17:29	aaelony	aaelony: I plead ignorance here. But it would be cool if it were so.
17:29	justin_smith	TEttinger: oh, sorry
17:29	TEttinger	hehe
17:30	justin_smith	aaelony: my above directed at TEttinger was actually responding to what you said
17:30	aaelony	justin_smith: I realize that
17:30	aaelony	:)
17:33	mcescher	iosjdf
17:33	mcescher	sorry
17:33	justin_smith	today's contestants in "tech acronym or keyboard noise" are...
17:34	ane	i once sneezed and wrote tanstaafl when i meant to write that is
18:00	blake_	Hey, all: Trying to use wrap-anti-forgery and ALL my POST pages are returning Invalid Anti-Forgery Token. I can see the token inside the page. I used the (anti-forgery-field) function. I put csrf/wrap-anti-forgery just above session.
18:00	blake_	And yet...