#clojure – 2016-04-12

2016-04-12

02:13	akonring	\list
02:14	ben_vulpes	,list
02:14	clojurebot	#object[clojure.lang.PersistentList$Primordial 0x794a8a15 "clojure.lang.PersistentList$Primordial@794a8a15"]
02:38	asdf12z_	if i have a map, is there an easy way to cherry pick a few keys off it to make a new map?
02:40	asdf12z_	ah select-keys
02:48	dysfun	asdf12z_: you may find http://conj.io/ a useful reference
02:48	dysfun	i tend to just ctrl-f through the page
02:54	ben_vulpes	so i get this bright idea to rewrite my deploy stack such that it never actually needs code on the remote hosts. "no github, no problem!" i think to myself. "compile locally, and ship jars around!" i think to myself "way faster than actually compiling or god forbid lein running on a t1.micro," i think
02:55	ben_vulpes	and it works fine. great, actually, at the office.
02:55	amalloy	uberjars are somewhat large
02:55	ridcully	rsync is your friend
02:55	amalloy	is where this is inevitably heading
02:55	ben_vulpes	but scping this bloated mason jar of deps over my home internet connection is, well, horseshit.
02:56	amalloy	i would be surprised if rsync helped at all with schlepping giant jars around
02:56	ben_vulpes	ridcully: are uberjars even amenable to optimization via rsync?
02:57	ridcully	well helps me. my rsyncs are about 5mb on 100mb wars
02:57	ridcully	but this is with gradle stuff
02:57	ridcully	but i doubt that lein will make such a mess with each new build, that rsync can not cope with it
03:02	ben_vulpes	ibd
03:02	ben_vulpes	ridcully: my heeeero
03:03	ben_vulpes	dunno why i never thought of that.
03:03	ridcully	well i'd expect it to be only usefull, if you have huge junks of jars, that stay more or less on the "same place" in the file
03:03	ridcully	also i dont know how how smart rsync is
03:04	ben_vulpes	me neither but that was about a zillion percent speedup
03:56	tolstoy	bittorrent sync? ;)
08:33	russellw	intaparse is slower than I was hoping for, is there a way to speed it up? http://stackoverflow.com/questions/36572997/any-way-to-speed-up-instaparse
08:50	dysfun	wow, that's impressively slow
08:59	dysfun	if you find there isn't a way to speed it up, i can recommend parse-ez. it shouldn't take long to convert such a small grammar
09:03	russellw	It is indeed! Thanks, though I'll probably just end up switching to a handwritten parser
09:53	Lewix	Hi
09:59	Glenjamin	russellw: could you try streaming into that?
09:59	Glenjamin	probably a bit late now
10:02	Glenjamin	it also sounds like instaparse intends to be fast enough for what you want to do, so submitting that question as an issue might give the maintainer something to look at
10:02	Glenjamin	there's a nice write up of its perf goals on the github project
10:03	Glenjamin	oh, it only takes a string
10:23	russellw	Glenjamin, yeah. In any case, the time taken to read the string from the file is negligible
10:25	russellw	But okay yeah, I've submitted it as an issue
10:49	timmc	not very insta
10:49	MJB47	insta is obviously short of instagate
10:51	ridcully	i don't remember the source (might be something from clojuretv), but the solution suggested there was to chunk the input - might not always be possible
10:52	justin_smith	asdf12z_: regarding constants in let vs. defs, it's the opposite, defs have a performance penalty compared to let, which is more efficient
10:52	justin_smith	though (def ^:const foo 1) should in practice be equal to (let [foo 1] ....)
11:22	om`	,(keyword "@")
11:23	clojurebot	:@
11:23	om`	,(read-string (keyword "@"))
11:23	clojurebot	#error {\n :cause "clojure.lang.Keyword cannot be cast to java.lang.String"\n :via\n [{:type java.lang.ClassCastException\n :message "clojure.lang.Keyword cannot be cast to java.lang.String"\n :at [clojure.core$read_string invokeStatic "core.clj" 3677]}]\n :trace\n [[clojure.core$read_string invokeStatic "core.clj" 3677]\n [clojure.core$read_string invoke "core.clj" 3677]\n [sandbox$eval49 i...
11:23	ridcully	,(keyword "Double/NaN")
11:23	clojurebot	:Double/NaN
11:23	om`	:@ is a legal keyword but the reader can't read it
11:28	MJB47	,(name (keyword "@")) ; atleast this works
11:28	clojurebot	"@"
11:29	justin_smith	no, it's an illegal keyword, but the keyword function is happy to construct it anyway
11:29	justin_smith	,(keyword " ")
11:29	clojurebot	:
11:29	justin_smith	keyword has no error checking whatsoever
11:30	tobyirc	hi! is anyone using Yesql with the latest java.jdbc?
11:30	tobyirc	because now jdbc logs deprecation warnings on every query
11:30	tobyirc	I can open a yesql issue but it seems println-ing the deprecation warnings is a bit heavy handed
11:30	tobyirc	"DEPRECATED: unrolled key/value arguments to query"
11:31	justin_smith	tobyirc: so the issue is that yesql uses functions in a way that is deprecated with the latest clojure.java.jdbc?
11:31	om`	thanks, justin (I wanted to use it to construct RDF prefixes)
11:32	tobyirc	justin_smith: yes but since it's the nicest way to do sql in clojure it seems that jdbc shouldn't have deprecated this :)
11:32	justin_smith	om`: yeah, keyword will accept any input, but the fact that it doesn't error is no proof that the keyword is acceptable, you should use the reader as a test for that if anything (but even then, the reader accepts keywords that the spec says are not valid)
11:32	om`	is there a way to know what keywords are (il)legal?
11:32	tobyirc	I think the secondary issue is that println isn't a great way to notify devs of deprecation
11:32	justin_smith	tobyirc: that sounds totally backwards to me
11:33	justin_smith	tobyirc: yeah, but java logging sucks
11:33	justin_smith	there's no universal logger they can count on there
11:33	tobyirc	indeed, but it would be nice to have a proper warning that could be disabled
11:33	tobyirc	or just note in the docs that it's deprecated instead of println
11:34	justin_smith	short-term hack would be with-out-str (which I admit is terrible)
11:34	tobyirc	yeah, that's pretty brutal :P
11:34	justin_smith	,(do (with-out-str (println "shouting into the void")) nil)
11:34	clojurebot	nil
11:36	jjmalina	anyone have any good articles/talks that make the clojure is more simple and better than scala for newcomers?
11:37	jjmalina	+argument
11:41	Matrixiumn	spanner: ay
11:42	Matrixiumn	¯\_(ツ)_/¯
11:42	tobyirc	justin_smith: turns out the correct answer is to just use hugsql http://www.hugsql.org
11:43	justin_smith	jjmalina: regarding the "simpler" part, I would consider that aspect uncontroversial, even to those who prefer Scala. Scala wants to abstract the JVM's model, Clojure follows it, one of these approaches is inarguably simpler than the other.
11:43	justin_smith	tobyirc: but yesql is pretty cool...
11:43	tobyirc	yep, although hugsql looks almost equivalent
11:44	justin_smith	tobyirc: oh, I had no idea...
11:45	tobyirc	yeah me either, a friend who turned me on to yesql says he uses this now and is much happier with it
11:48	jjmalina	justin_smith the argument I'm being given is that clojure's syntax is lisp therefore scala is easier for new people
11:48	MJB47	thats subjective
11:48	MJB47	i would argue lisp syntax is much simpler, but less known/familiar
11:48	justin_smith	jjmalina: simple != familiar
11:49	justin_smith	jjmalina: clojure is unfamiliar to most, but lispish syntax is an order of magnitude simpler than the alternatives
11:49	Glenjamin	is Scala ML syntax? or some weird Java/ML hybrid?
11:49	justin_smith	Glenjamin: the latter
11:49	jjmalina	justin_smith i agree. but not sure how to express that argument
11:49	jjmalina	so I'm asking y'all for help :)
11:49	Glenjamin	i seem to recall it as ruby-esque precedence issues
11:49	tobyirc	because clojure is a lisp, you're able to tap into 50+ years of computer science literature. Scala is it's own thing and a dead end lineage. Your Scala knowledge will not be useful in the future.
11:50	gilch	operator precedence, for one thing.
11:50	Glenjamin	jjmalina: who do you need to convince? Can you make them watch simple made easy?
11:50	justin_smith	jjmalina: look at eg. logjban - an english speaker would call it "complicated" because they don't know it yet, but it is much simpler than english
11:50	Glenjamin	iirc there are some scala constructs where a() and a () do very different things
11:50	jjmalina	Glenjamin CTO
11:50	justin_smith	and this isn't a random assertion - it's a measurable property of its rules - same with clojure and scala
11:50	Glenjamin	then yeah, ask them to watch simple made easy before any more discussion
11:51	justin_smith	jjmalina: there could be an argument to be made that familiar is better than simple, but "simple" means something, and scala is not it
11:51	Glenjamin	see if they have an equivalent talk they think you should watch to be convinced
11:51	gilch	try writing a parser for Scala vs one for Clojure. which is easier?
11:51	Glenjamin	justin_smith: in clojure-land we choose to try and be precise about being simple, i'd argue that's not quite the same as "simple means something"
11:51	jjmalina	i like simple made easy, though it's a long talk
11:52	MJB47	i would go with, explain the 4 basic data structures, and thats it
11:52	MJB47	thats the syntax
11:52	MJB47	everything else is sugar
11:52	Glenjamin	except reader conditionals :p
11:52	justin_smith	Glenjamin: systems theory defines it :P - simple and complex are not weird new definitions hickey invented
11:52	Glenjamin	justin_smith: idd, but that precise use is not widely adopted
11:52	justin_smith	Glenjamin: complexity is measurable via systems theory, and simplicity is a low complexity measure
11:52	jjmalina	but yeah i think there are ways to dissect the familiar -> simple argument
11:53	justin_smith	these aren't subjective things, they are measurable
11:53	Glenjamin	words are all subjective
11:53	Glenjamin	you're using precise definitions, which i agree with
11:54	Glenjamin	but the person you're talking to might not
11:54	dysfun	language is hard, yo
11:54	Glenjamin	this is why simple made easy starts with a discussion of how the terms will be used, and why I recommend it so much
11:54	jjmalina	i'm coming from python and clojure seems more familiar to me than scala tbh
11:55	jjmalina	though I started writing my python as if it were clojure almost :P
11:55	jjmalina	lol
11:55	Glenjamin	"this is a term, this is a precise meaning, this is why that's useful. Now: lets compare things using this term"
11:55	jjmalina	i tried reading "Programming Scala" and it was quite overwhelming
11:56	dysfun	Glenjamin: pah, just TLA the wibblywobble and frobnicate the flimflam
11:56	justin_smith	Glenjamin: you are right, I learned systems before I learned to program even, so the whole "this is what simple means" thing was just background noise to me, thanks for reminding me that most people lack that background
11:56	Glenjamin	see, this is why I like this IRC channel
11:56	dysfun	jjmalina: it's a bit of a kitchen sink language, that's why the book is so big
11:57	Glenjamin	Although I did actually manage to get in and out of haskell with an answer and no arguments the other day
11:57	dysfun	i did eventually find a use for it: propping up my monitor
11:57	dysfun	it combines the functionality of two books into one
11:57	Glenjamin	so maybe IRC is getting better
11:58	dysfun	i got useful advice in #haskell today
11:58	justin_smith	Glenjamin: imho arguing is for when you respect the other person's intellect and think they might teach you something, if I just think someone is wrong it's not worth the wear on my keyboard switches to keep typing :)
11:59	Glenjamin	mm, the times when i do let myself drawn into an argument it's usually because I want to understand why the other person thinks something - what context do they have which i'm missing
11:59	dysfun	justin_smith: the harder thing is when you respect the person but not the viewpoint. quite a few of my friends have been embarrassing themselves of late :/
12:00	justin_smith	dysfun: oh yeah... when politics comes into play for example it can get painful...
12:01	dysfun	actually in this case, someone who has decided their pet technology is the best thing ever slagged off basically every language ever invented. badly. in ways i know to be wrong (in particular, clojure)
12:01	rcassidy	yeah, favoring a certain tool in the toolbox is a quick way to not get jobs done
12:02	Glenjamin	s/favouring/blindly favouring/ i'd say :)
12:02	dysfun	yeah, he focused his career energy on getting a name with one tool
12:02	justin_smith	rcassidy: "I need to remove this screw, and since I like my shiny sledgehammer so much, I'll just use that"
12:02	Glenjamin	hopefully everything I don't like, I can articulate why
12:02	Glenjamin	and ideally, I can articulate why others do like it
12:03	dysfun	Glenjamin: until you can give me ten good reasons you hate a thing, you don't know it
12:03	Glenjamin	i do still get a bit annoyed when people tell me go is simple though :D
12:04	dysfun	go is the new php. except with concurrency. and non-thread-safe basic collections
12:04	Glenjamin	this page is my go-to for why I don't like it: https://github.com/golang/go/wiki/SliceTricks
12:04	dysfun	i am on a JVM performance list and the gist is "aww, that's sweet, they're finally having the discussion we had ten years ago about GC"
12:08	jjmalina	this ones good too http://www.jtolds.com/writing/2016/03/go-channels-are-bad-and-you-should-feel-bad/
12:09	Glenjamin	damn, I thought channels were one of the good bits
12:09	jjmalina	it's easy to get yourself into channel/go-routine hell
12:09	MJB47	they are controversial from what i can tell
12:15	dysfun	Glenjamin: basically, it's not CSP that is broken, it's go
12:15	Glenjamin	hrm, does that teardown apply to clojure too?
12:15	dysfun	not really
12:15	Glenjamin	the crux appears to be stopping a go-routine
12:16	dysfun	and not leaking them
12:16	dysfun	(unlike core.async, you need to close channels)
12:17	jjmalina	it's funny that core.async has a "go" function
12:17	dysfun	it's not funny, that was rich's tribute to go for popularising the model
12:17	justin_smith	dysfun: aren't there issues with leaking resources in core.async too? (eg. go blocks that don't exit, so their resources stick around, if they are not exited properly?)
12:18	dysfun	justin_smith: not on the same scale
12:18	justin_smith	why's that?
12:18	justin_smith	(sorry for the toddler level question)
12:18	dysfun	go simply has a broader canvas of destruction
12:18	dysfun	you have to explicitly free things etc.: you will fuck up more often
12:19	justin_smith	ahh, needing to explicitly reclaim things could get ugly with CSP, yeah, Ican see that
12:19	dysfun	and of course you'll be needing to guard everything with mutexes
12:19	dysfun	data is generally mutable in go
12:20	dysfun	that article has a good example. but in the real world you need to do this all the time
12:20	dysfun	core.async comparatively lets you forget about things. go adds programmer load
12:41	sdegutis	Never mind, fixing it now.
12:43	justin_smith	I wonder if that was in reference to "justin_smith I have a race condition" at 7 last night, lol
12:43	Glenjamin	so if incoming requests started go blocks per "game", I don't see why we wouldn't hit the issue about zombie games filling up
12:43	Glenjamin	apart from that in clojure we'd probably use an atom for that anyway
12:44	justin_smith	Glenjamin: well, it's a question of making sure the go blocks exit, right?
12:44	Glenjamin	i think so - in the go example they just loop on the incoming request, no :exit message
12:45	Glenjamin	but that seems just as easy to do in clojure
12:45	Glenjamin	so i wonder if there's something else i'm missing
13:26	jjmalina	rewatching simple made easy and it's hitting me pretty hard
13:27	prohobo	jjmalina: what?
13:28	jjmalina	it's very relatable :)
13:28	prohobo	what is it though?
13:29	jjmalina	prohobo http://www.infoq.com/presentations/Simple-Made-Easy
13:29	prohobo	thx
13:30	prohobo	i like this
13:30	prohobo	ty
13:30	prohobo	here's an example of this in action: https://www.reddit.com/r/GlobalOffensive/comments/4efmes/this_would_be_a_couple_of_lines_of_code_for_valve/
13:31	prohobo	> valve can't add a simple button to a menu because of design complexity
13:31	prohobo	> everyone goes nuts
14:08	jrc_	Hi guys, I'm new to Clojure. I installed it via MacPorts, but Leiningen is using a different version somehow: http://pastebin.com/raw/vNWZ1fzB Is it possible that an older version of Clojure ships with OS X? And if so how can I configure Leiningen to use the Macports version?
14:09	justin_smith	jrc_: just use leiningen, don't use a package manager, leiningen is a better package manager than any one your OS offers
14:10	jrc_	So Clojure comes bundled with Leiningen?
14:10	justin_smith	jrc_: clojure is a library, leiningen uses your config to decide which version of that library to use
14:10	justin_smith	jrc_: there is no global install of clojure, as far as leiningen is concerned, this is actually a very nice thing
14:11	justin_smith	jrc_: leiningen is a tool that figures out which jars to download and add to the classpath when building / running your app, one of those jars is clojure.jar
14:12	jrc_	Oh I see, I had the wrong version in the project.clj dependencies
14:12	jrc_	Thank you for the clarification, justin_smith
14:13	justin_smith	np, glad Icould help
15:17	mettekou	Is there an advantage of refs over atoms when updating a single storage location?
15:19	turbofail	nope
15:33	ben_vulpes	https://www.refheap.com/117424 << slamming into interop problems. anyone know why clojure can't find a ctor for this class?
15:39	ben_vulpes	aaaaa
15:39	ben_vulpes	afaict i'm doing exactly this, but in different parens: https://github.com/thebusby/clj-aws-iam/blob/master/src/aws/sdk/iam.clj#L38
15:45	ben_vulpes	picking the right version helped, fwiw
15:46	ben_vulpes	no idea why 1.3.23 didn't work though. NO TIME NO TIME.
16:31	cespare	Does anyone know why #^:optional [:foo] works? (It seems to be the same as ^:optional [:foo] )
16:31	cespare	^ isn't mentioned as something that can follow the # in http://clojure.org/reference/reader#_dispatch
16:34	hiredman	#^ is old deprecated syntax that meant the same thing as ^
16:34	cespare	ah, thanks!
17:00	bmuk`	Hey everyone, I'm getting a classcastexception when I try to json/read a file I've slurped: https://gist.github.com/bmuk/7afe39e86b47f5c6cd611690904d9918
17:02	justin_smith	bmuk`: json/read wants something it can read from, you can use read-string or pass it the file instead of the text slurped out of the file
17:02	bmuk`	so I can just pass it a path?
17:02	justin_smith	(eg use clojure.java.io/file instead of slurp
17:03	justin_smith	bmuk`: slurp does not return a path either
17:03	justin_smith	maybe a path works, Iknow a file would
17:03	bmuk`	java.lang.ClassCastException: java.io.File cannot be cast to java.io.Reader
17:03	bmuk`	changed slurp to io/file
17:04	justin_smith	try io/reader maybe? something like that should work
17:05	bmuk`	that worked, thanks! It's sort of slow with how many files I'm throwing at it, though
17:12	asdf12z_	whats a beautiful way to do error handling, specifically im trying to do a http request, i wonder if there's a better way than if statement? or case statement
17:14	faxmodem	asdf12z_: try?
17:15	asdf12z_	ok just wanted to know my options, still learning, and i shouldn't say statements, i meant expressions hehe
17:16	justin_smith	asdf12z_: one nice compromise between throwing exceptions to indicate failure, and using failure-values, is to throw an ex-info
17:16	justin_smith	(doc ex-info)
17:16	clojurebot	"([msg map] [msg map cause]); Create an instance of ExceptionInfo, a RuntimeException subclass that carries a map of additional data."
17:16	justin_smith	so the one catching the ex-info can use that map to look for useful data about the failure
17:19	asdf12z_	justin_smith, it feels weird to have a user catch an exception though? especially when the outcome is kind of predictable, like in a http request it either succeeds or fails?
17:20	justin_smith	asdf12z_: exceptions are for things that a caller would know how to handle
17:21	justin_smith	asdf12z_: if it is not recoverable, use an error instead
17:21	aloha_	Hi! I’m having a hard time passing a little Ruby function to Clojure (it’s for a little test I did). I was able to do it in Ruby no much trouble, I'm a Rails guy, but I don’t understand almost nothing of Clojure as I only did some little things with Clojure some years ago. Is a little function to print an array of strings (and nested arrays of strings) with a each index
17:22	aloha_	For example, if you have this array: `list = ['a stringy', ['y','e','s'], 'cheese', ['tomato']]` and you call the function printList (let’s call it that way) like this `printList('Goo', list)`, you would get the following output: `Goo.0: a stringy \n Goo.1.0: y \n Goo.1.1 : e` etc
17:22	justin_smith	asdf12z_: you can fight the platform (jvm) and use some kind of monad instead, (some sort of Maybe), but this is computationally expensive, and increases complexity to little benefit, IMHO
17:22	sdegutis	Is there something like assert that returns your value if it passes a test?
17:22	sdegutis	Something like (assert-test pos? n) which returns n if it's pos? or throws an exception otherwise.
17:22	justin_smith	sdegutis: doto
17:22	aloha_	I pasted in Repl.it if you want to see my little Ruby solution: https://repl.it/CEt1/0
17:22	asdf12z_	justin_smith, ok that's good info, i just didn't know if it was normal for me to expect users of my lib to catch
17:23	sdegutis	justin_smith: Exactly.
17:23	asdf12z_	since i just want to be able to communicate back heres the success data, or err
17:23	ben_vulpes	aloha_: i...
17:23	sdegutis	But I thought there was a built-in thing.
17:23	ben_vulpes	don't think things work like that around here.
17:23	ben_vulpes	you might do something with a for loop and format but uh
17:23	ben_vulpes	why do you need the list.idx.subidx noise?
17:24	sdegutis	justin_smith: also, doto doesn't work
17:24	ben_vulpes	oh that's your formatter in ruby i see
17:24	aloha_	Imagine you can do that little function in 2 minutes, just iterate each with index and print if its a string, or call itself recursivelly if not
17:25	aloha_	yeah in ruby to interpolate variables in strings you use "TEXT#{var}TEXT"
17:25	aloha_	like in JS "text" + var + "text"
17:25	ben_vulpes	,(format "text%stext" "NOTTEXTATALL")
17:25	clojurebot	"textNOTTEXTATALLtext"
17:26	ben_vulpes	,(def z :zazzle)
17:26	clojurebot	#'sandbox/z
17:26	ben_vulpes	(format "text:%s:text" z)
17:26	ben_vulpes	,(format "text:%s:text" z)
17:26	clojurebot	"text::zazzle:text"
17:27	aloha_	cool!
17:27	ben_vulpes	something like that?
17:27	justin_smith	sdegutis: (fn [x f] (assert (f x)) x) is what you want, right?
17:27	sdegutis	Yeah.
17:27	sdegutis	I'll just do that for now.
17:27	sdegutis	But I really thought there was some function in clojure.core that was like that.
17:27	justin_smith	oh, and you might want a custom assertion string too...
17:27	sdegutis	Right on!
17:27	justin_smith	sdegutis: not that I know of
17:28	aloha_	ben_vulpes something like that for the formatting, yeah
17:29	sdegutis	Pkay, thanks.
17:30	aloha_	but how do I loop an array (with an index) and check if the item is a string, and if it is print it like that format (format "text:%s:text" z) and if not, recursivelly loops again the same function?
17:30	ben_vulpes	loop and recur
17:30	aloha_	I took the FizzBuzz code for Clojure from Rosetta code but can´t understand it, it’s like backwards for me haha
17:30	sdegutis	Uh oh.
17:30	sdegutis	I'm about to use (flatten).
17:30	sdegutis	help whatdoido
17:31	aloha_	then I thought maybe there is a clojure irc with lots of clojure hackers haha
17:31	sdegutis	aloha_: unfortunately nope theres not
17:32	aloha_	haha :p
17:32	sdegutis	,(str "foo" 3 "bar")
17:32	clojurebot	"foo3bar"
17:32	sdegutis	,({get get} {get get} {get get})
17:32	clojurebot	{#object[clojure.core$get 0x4330ea6a "clojure.core$get@4330ea6a"] #object[clojure.core$get 0x4330ea6a "clojure.core$get@4330ea6a"]}
17:32	sdegutis	,(= {get get} ({get get} {get get} {get get}))
17:32	clojurebot	true
17:33	aloha_	so how do I do loop and recur? don´t kill me plz
17:33	jeaye	,(doc loop)
17:33	clojurebot	"([bindings & body]); Evaluates the exprs in a lexical context in which the symbols in the binding-forms are bound to their respective init-exprs or parts therein. Acts as a recur target."
17:34	justin_smith	that doc string could be a 10 page tutorial instead
17:35	jeaye	Yeah, it's not very helpful.
17:35	sdegutis	Why doesn't this work?
17:35	sdegutis	,(keyword :foo :bar)
17:35	clojurebot	#error {\n :cause "clojure.lang.Keyword cannot be cast to java.lang.String"\n :via\n [{:type java.lang.ClassCastException\n :message "clojure.lang.Keyword cannot be cast to java.lang.String"\n :at [clojure.core$keyword invokeStatic "core.clj" 595]}]\n :trace\n [[clojure.core$keyword invokeStatic "core.clj" 595]\n [clojure.core$keyword invoke "core.clj" 595]\n [sandbox$eval119 invokeStatic "N...
17:35	sdegutis	Why it has to be astring?
17:36	sdegutis	,(keyword "foo" "bar")
17:36	clojurebot	:foo/bar
17:38	jeaye	sdegutis: The one taking just a name can be a string, symbol, or keyword.
17:38	jeaye	The one taking a ns and name needs both to be strings.
17:39	jeaye	https://www.conj.io/store/v1/org.clojure/clojure/1.8.0/clj/clojure.core/keyword
17:40	jeaye	If you're asking for the actual "why," I don't know.
17:40	sdegutis	Right.
17:40	jeaye	,(keyword (str ns) "foo")
17:40	clojurebot	:sandbox/foo
17:40	sdegutis	Thanks! jeaye.
17:40	sdegutis	jeaye: You been doing CLojure long?
17:41	jeaye	About 6 months. Not long.
17:43	hiredman	use ns-name, not str
17:47	sdegutis	Whoa, concat is literally unnecessary. It's probably pre-processed out during read time.
17:47	sdegutis	,(= () (concat))
17:47	clojurebot	true
17:47	sdegutis	They're identical.
17:48	sdegutis	What does flatten due to maps?
17:49	sdegutis	,(flatten [{:a [{:b 2}]]}])
17:49	clojurebot	#<RuntimeException java.lang.RuntimeException: Unmatched delimiter: ]>
17:49	sdegutis	,(flatten [{:a [{:b 2}]}])
17:49	clojurebot	({:a [{:b 2}]})
17:49	sdegutis	,(flatten [{:c 3, :a [{:b 2}]}])
17:49	clojurebot	({:c 3, :a [{:b 2}]})
17:49	sdegutis	Hmm. Weird.
17:56	bmuk`	I'm not sure why, but my parse-file-set function is returning {}? https://gist.github.com/bmuk/49c9be5eda264966c26f19cae9b5b126
17:58	sdegutis	Whoa, why does assert not throw Exception?
17:58	sdegutis	I mean, AssertionError does not hail from Exception!
17:59	bmuk`	am I not using swap! correctly?
18:05	hiredman	~map
18:05	clojurebot	map is lazy
18:05	bmuk`	but I requested the final value?
18:06	ridcully	what is gained here by using that local atom?
18:07	bmuk`	probably nothing; my thought process was: mutability -> atom
18:08	bmuk`	if I don't update the value I'll just be calling with an empty {} every time
18:11	bmuk`	hiredman: is there a strict version of map?
18:11	amalloy	bmuk`: you don't need mutability at all for that. it's a classic reduce
18:11	ridcully	well i have not looked at all of it, but at first glance this looks like a reduce
18:11	ben_vulpes	http://i.imgur.com/bZSGX6M.png << gross gross gross gross gross
18:12	ben_vulpes	what'd be a more idiomatic approach to marshalling all of this oop around?
18:13	amalloy	ben_vulpes: the grossest part of this is that you linked to a png instead of text
18:13	ben_vulpes	:(
18:14	ben_vulpes	amalloy: meanie
18:14	ben_vulpes	https://www.refheap.com/117432
18:14	bmuk`	amalloy: you're right
18:14	bmuk`	can I keep parse-api-call the same? Trying to wrap my head around converting this to reduce
18:15	ridcully	is that def right in the middle intended?
18:16	ben_vulpes	i did not want to, no.
18:16	amalloy	bmuk`: you can mostly. you might have to flip the order it takes arguments
18:17	ben_vulpes	alternative appeared to be to bind all of the side-effecty shit to _ in the let
18:17	ben_vulpes	i am already adequately guilty of doing all of my imperative programming in let statements, ridcully
18:17	ben_vulpes	but perhaps here it is justified? i bring it to the sages for dissection.
18:17	amalloy	ben_vulpes: you can inline anything that's only used once
18:17	ben_vulpes	no, no. in-fn defs are never justified.
18:17	amalloy	user-request, for example
18:18	amalloy	i would probably turn this into a mess of doto and ->, which some people would hate
18:19	ridcully	i guess even some let cascade would look better
18:19	ben_vulpes	> let cascade
18:20	ben_vulpes	yeah i considered that too
18:20	ben_vulpes	i mean it's trivially refactored, i'm mostly curious about how the pros would handle this kind of oop marshalling cleanly.
18:21	ben_vulpes	(justin_smith ??)
18:22	bmuk`	amalloy: this worked, thanks a billion: https://gist.github.com/bmuk/49c9be5eda264966c26f19cae9b5b126/revisions
18:23	sdegutis	Throwable it is then
18:24	amalloy	ben_vulpes: you could do something like https://gist.github.com/amalloy/b7a552dd3d2d16e66cff80c7c04b4180, which is what i was saying re doto
18:25	ridcully	ben_vulpes: well that leaves me out ;) i'd try to bring the two policy thingies up into the let (use doto) and then deal with the client at the end. if the policy-result needs another let, so be it. then try to inline the policy thingies and see how that looks
18:26	ben_vulpes	amalloy: notbad
18:26	ben_vulpes	way cleaner
18:26	ben_vulpes	ty
18:26	ben_vulpes	ridcully and friends thanks as well
18:26	amalloy	doto is a better java than java
18:26	ben_vulpes	hyuuuuu
18:34	aloha_	well my first try to make the printList function is giving a StackOverflowError (imagine something with the loop. here it is: https://gist.github.com/anonymous/7f2d86b1895bebb1aa573febaf3b99f8
19:08	momerath	so, I just did a bunch of misguided debugging surround lein and my system, because it was stalling out, with no visual output (and I get some at compile time from macro debug prints). I discovered the problem was (as I should have known because I just did it), that I'd moved a top level def, which called a function that wasn't safe to call at compile time, from a test namespace, where it worked, to a
19:08	momerath	src namespace. So, I don't need help debugging that, but can anyone tell me if there is an idiomatic way to assert in functions like that (ie, what's a good way to detect that it's compile time?)?
19:11	amalloy	momerath: ns will be bound to something interesting while compiling. at runtime it's probably something like clojure.core, or user
19:12	amalloy	but of course "compile time" includes anything you're doing in a repl
19:12	momerath	hrm- yeah, that's a problem :-/ I guess I'll just guard against use when the specific environmental things are missing from a given function
19:46	justin_smith	momerath: the real thing to do is not put things with side effects at the top level of your code
19:46	justin_smith	and if you do, you'll learn to recognie the errors this causes
19:47	tolstoy	Would `delay` help?
19:49	momerath	I do; this is the first time I've run into it in 18 months of full time clojure. it happened because it was safe to do in a test.check test that I was still developing, and there seems to be a trick to calling functions defined in test namespaces at the repl (ie, (ns 'my-proj.thing-test) succeeds but the functions are undefined)
19:50	justin_smith	momerath: ns does not load source files (except via require clause)
19:50	momerath	ah- that would explain it. so I should look to 'require'?
19:50	justin_smith	(doto 'my-proj.thing-test require in-ns)
19:51	justin_smith	is the nifty way to do it
19:51	momerath	heh- that is nifty :)
19:51	momerath	thanks!
20:57	bmuk	I'm having trouble writing a function to operate on my data. I have hashmap with method names as keys, and a list of hashmaps as values, each with a :request key (hashmap value) and a :response key (same). I want to reduce the list of calls to a single hashmap (:request and :response as keys) with all the keys present in the entire list accounted for and with the Type of the current value as their value
20:57	bmuk	Right now I'm like 3 lambdas deep and I realize I'm probably going about this the wrong way
20:57	clojurebot	It's greek to me.
20:58	TEttinger	hey bmuk
20:59	TEttinger	are they method names or methods?
20:59	TEttinger	because you CAN use fns as keys
20:59	bmuk	method names
20:59	TEttinger	,(map #((first %) (second %)) {inc 1 dec 10})
20:59	clojurebot	(2 9)
21:00	bmuk	they are strings, not clojure method names
21:00	TEttinger	ok
21:00	bmuk	hang on, I'll filter out sensitive data and make a gist of an example
21:00	tolstoy	Hi folks. Is there a way to detect arity errors at runtime?
21:01	tolstoy	Sorry, compile time?
21:01	amalloy	you can run eastwood. it catches some such errors
21:01	TEttinger	bmuk: is Type referring to Typed Clojure stuff?
21:01	tolstoy	But in general, that's just the nature of the dynamic language, right?
21:02	amalloy	yes, the languages is designed to defer type errors to runtime
21:02	bmuk	TEttinger: no, the result of (type %)
21:04	TEttinger	so what does the current value refer to in the last section of your message?
21:05	bmuk	it's hard to explain since it's so nested, I'm cleaning up the test data now and I'll post a gist
21:06	TEttinger	I'm pretty sure this will be possible with some fancy one-liners, knowing the people here who like to code golf :)
21:07	TEttinger	as the saying goes though, it takes a village to write a clojure one-liner
21:08	amalloy	i predict that with "standard" indenting and newlines it will take 4-7 lines, but could be squeezed into one on irc
21:09	TEttinger	with "non standard" indenting it could be stretched to many more!
21:10	bmuk	here is an example of a map of just one method: https://gist.github.com/bmuk/46df9d90ccd3fde52bae5bb80625b1be
21:14	bmuk	I want a map with "SignIn" as the key and a map as the value (henceforth called apicall). Apicall has two keys, :request and :response. The value associated with :request should be a map with a superset of the keys in every :request in the current list of maps associated with "SignIn", the values of those keys should be the type of the current values where possible, nil where not. :response should be the same
21:16	bmuk	Basically the end result I'm looking for is a map from api method names to request/response object pairs that have all the possible data. I want to use this to generate documentation where I can
21:24	amalloy	bmuk: i would write https://gist.github.com/amalloy/f4744a190594c6d2f25909b9a8370f84
21:24	amalloy	where "inputs" is the map you pasted
21:25	amalloy	took me 8 lines, though. i guess i could have collapsed line 3-4 into: {}, (for ...)
21:26	amalloy	and it doesn't address the question of maps as arguments
21:29	bmuk	thank you amalloy!
21:29	amalloy	like a lot of things, you can split this into two parts: one part that consumes the raw input and produces some intermediate useful structure (here, a list of pairs like [["signin" :request "invitation-id"] String]), and then a second part that consumes that useful structure, often with a reduce
21:30	bmuk	what is generally your strategy when dealing with a complex structure like this?
21:31	amalloy	mmm. iterate over it, really, until i get to a point when there's nothing interesting left to iterate over, and then see what useful data i can produce
21:31	amalloy	for is pretty good at consuming nested structures, so i often start there
21:32	bmuk	It definitely looks like it; I wasn't aware of for
21:32	amalloy	this particular question is one i've answered a lot of times, so i already knew the answer. you want to iterate over a nested map and produce a series of the legal keyseqs in that map
21:33	bmuk	I'm essentially bumbling through learning clojure by making useful things
21:33	amalloy	good plan
21:56	bmuk	Is this stylistic and idiomatic? https://gist.github.com/bmuk/49c9be5eda264966c26f19cae9b5b126
21:56	bmuk	in other words is there anything glaring I can improve?
22:00	amalloy	there's nothing too awful. your -main is rather messy in general; you're missing a chance to simplify with destructuring at https://gist.github.com/bmuk/49c9be5eda264966c26f19cae9b5b126#file-core-clj-L16; #(cons whatever %) should probably just be conj whatever in https://gist.github.com/bmuk/49c9be5eda264966c26f19cae9b5b126#file-core-clj-L40
22:02	bmuk	what do you mean specifically regarding destructuring?
22:08	amalloy	you're taking in a 3-vector, and instead of destructuring it you call first and last
22:14	bmuk	ahh got it
22:16	bmuk	conj over cons because I want to append instead of prepend?
22:17	amalloy	because you don't care whether you append or prepend, and conj fits into the update-in model better
22:18	bmuk	ok. would breaking out the argument parsing into it's own method make -main more palatable?
22:31	sdegutis	What's the thing like flatten but only at one level?
22:34	asdFREjglk	not sure.. concat can do that...
22:34	amalloy	~flatten
22:35	clojurebot	flatten is rarely the right answer. Suppose you need to use a list as your "base type", for example. Usually you only want to flatten a single level, and in that case you're better off with concat. Or, better still, use mapcat to produce a sequence that's shaped right to begin with.
22:35	amalloy	bmuk: i don't really have time for detailed feedback on -main now, sorry
22:37	bmuk	that's fine
22:44	sdegutis	Thanks
23:50	tolstoy	Golang insists on tabs for spacing? shudder
23:50	blockzombie	oh really?
23:50	jack_rabbit	Yeah, there's a few formatting things golang insists on that are sort of crappy.
23:50	blockzombie	I have been playing with it and didn't notice that
23:50	jack_rabbit	there are, rather.
23:50	blockzombie	ew
23:51	blockzombie	I'm ok with how python does it
23:51	tolstoy	https://golang.org/doc/effective_go.html#formatting See the "Indentation" hanging indent list.
23:51	tolstoy	"We use tabs for indentation and gofmt emits them by default. Use spaces only if you must."
23:51	blockzombie	thanks for the link
23:52	blockzombie	oh ok but it's not a compile error
23:52	tolstoy	So, "insists" is a bit strong, but maybe "strongly encourages" is more accurate?
23:52	blockzombie	ok so they're weird, not unreasonable
23:53	tolstoy	Yeah. But, oy. I think Emacs isn't too friendly with that kind of thing.
23:53	tolstoy	And then looking at code in github with those wide, wide tabs.....
23:54	tolstoy	But, yes. A matter of taste.
23:55	tolstoy	Seems like a neat little non-functional language, though. I wonder if it's a much smaller memory footprint than the JVM?