#clojure – 2015-12-03

2015-12-03

03:07	kenrestivo	i'm getting a classnotfound error, but the jar is on the classpath and the class is inside the jar... are there weird java version mismatch issues that might be causing this?
03:07	kenrestivo	i'm not a java guy so please forgive my jvm ignorance
03:21	tolstoy	,(String. (byte-array '(-61 -72)))
03:21	clojurebot	"ø"
03:22	tolstoy	Are you using -jar?
03:26	TEttinger	kenrestivo: what does your command line look like?
03:26	TEttinger	if it isn't an uberjar you likely need -cp to change the classpath
03:28	jonathanj	ugh
03:28	jonathanj	Error compiling:
03:28	jonathanj	/Users/jonathan/Coding/clj-documint/test/documint/session_test.clj:21:14 No
03:28	jonathanj	single method: get_session of interface: documint.session.ISessionFactory
03:28	jonathanj	found for function: get-session of protocol: ISessionFactory
03:29	jonathanj	the slightly important part that error seems to totally forget to mention is the object the method is trying to be invoked on
03:30	jonathanj	pretty sure if it had said "No method get-session for object HeyGuysThisIsNotASessionFactory" i would have spent a lot less time scratching my head
03:30	tolstoy	I get those a lot. Missing parameter for me. ;)
03:37	thatslifeson	how to convert a string to a vector without all of the additonal \? i.e. 12345 => [\1 \2 \3 \4 \5]
03:37	thatslifeson	looking for [1 2 3 4 5]
03:38	thatslifeson	into [] is adding the \
03:42	tolstoy	,(mapv str "abc")
03:42	clojurebot	["a" "b" "c"]
03:43	beaky	i love mapv
03:43	TEttinger	,(mapv #(- % 42) 12345)
03:43	clojurebot	#error {\n :cause "Don't know how to create ISeq from: java.lang.Long"\n :via\n [{:type java.lang.IllegalArgumentException\n :message "Don't know how to create ISeq from: java.lang.Long"\n :at [clojure.lang.RT seqFrom "RT.java" 535]}]\n :trace\n [[clojure.lang.RT seqFrom "RT.java" 535]\n [clojure.lang.RT seq "RT.java" 516]\n [clojure.core$seq__4116 invokeStatic "core.clj" 137]\n [clojure.co...
03:43	TEttinger	,(mapv #(- % 42) "12345")
03:43	clojurebot	#error {\n :cause "java.lang.Character cannot be cast to java.lang.Number"\n :via\n [{:type java.lang.ClassCastException\n :message "java.lang.Character cannot be cast to java.lang.Number"\n :at [clojure.lang.Numbers minus "Numbers.java" 137]}]\n :trace\n [[clojure.lang.Numbers minus "Numbers.java" 137]\n [clojure.lang.Numbers minus "Numbers.java" 3692]\n [sandbox$eval77$fn__78 invoke "NO_SO...
03:43	TEttinger	,(mapv #(- (int %) 42) "12345")
03:43	clojurebot	[7 8 9 10 11]
03:43	TEttinger	,(mapv #(- (int %) 48) "12345")
03:43	clojurebot	[1 2 3 4 5]
03:44	tolstoy	,(mapv #(Integer/parseInt %) (mapv str "123"))
03:44	clojurebot	[1 2 3]
03:44	TEttinger	yeah, tolstoy has a good approach
03:45	TEttinger	the two mapv
03:45	tolstoy	Isn't that a function that turns a method into a clojure function?
03:45	TEttinger	memfn
03:45	TEttinger	(doc memfn)
03:45	clojurebot	"([name & args]); Expands into code that creates a fn that expects to be passed an object and any args and calls the named instance method on the object passing the args. Use when you want to treat a Java method as a first-class fn. name may be type-hinted with the method receiver's type in order to avoid reflective calls."
03:45	TEttinger	but your case is a static function not a method
03:46	tolstoy	Ah. I think I've been down that road before.
03:46	TEttinger	,(mapv (comp read-string str) "12345")
03:46	clojurebot	[1 2 3 4 5]
03:46	tolstoy	,(mapv #(Integer/parseInt (str %)) "1234")
03:46	clojurebot	[1 2 3 4]
03:47	tolstoy	Or turn it into a transducer? ;)
03:47	TEttinger	,(mapv (comp read-string str) "123+-")
03:47	clojurebot	[1 2 3 + -]
03:47	TEttinger	neat
03:47	TEttinger	it works for one-char variable names too...
03:49	tolstoy	Ever had the case where there's a ö in your json on the client and when it arrives in your java server (aleph) over a websocket (FreeBSD), it because a "?"?
03:50	beaky	https://www.youtube.com/watch?v=c2wyg9-4rR0 wow his posteroir deltoids
03:50	beaky	oops wrong channel
03:54	jonathanj	i read some interesting anecdote that people like Lu Xiaojun have a mechanical advantage in weightlifting by having a shorter than normal femur
04:15	jonathanj	can i combine (doto) and (..)?
04:15	jonathanj	(doto obj (.. some nested method arg))
04:16	jonathanj	to mean, in Java: obj.some.nested.method(arg)
05:06	sara_	Hi,Do anyone know how to redirect into a new page in clojure using om and react
05:07	jonathanj	I have a concurrency problem I'm not too sure how to resolve: https://pb.codehash.net/17aa60b4ee7a4e34bb2d4b1677325451
05:08	jonathanj	I don't know when to (.close src-doc) because I don't know how to tell when all the futures have been resolved.
05:08	beaky	is there something like >>=, <$>, and <*> in clojure
05:08	jonathanj	(piped-input-stream) is ring.util.io/piped-input-stream: https://github.com/ring-clojure/ring/blob/1.4.0/ring-core/src/ring/util/io.clj#L11
06:57	ashwin_	how can I decode cookies recieved in a request?
06:57	ashwin_	is there a standard library?
07:03	ashwin_	I think this must be a standard problem
07:03	ashwin_	has'nt anyone faced this before?
07:14	the_nonameguy	ashwin_: https://ring-clojure.github.io/ring/ring.middleware.cookies.html ?
07:15	the_nonameguy	are you looking for this, or the decoder function itself?
07:20	ashwin_	the_nonameguy, I need the decoder function itself
07:21	ashwin_	the_nonameguy: even the ring library just url decodes the string
07:41	jonathanj	hrm, i'm having some trouble getting clojure.data.json/write to do the right thing
07:48	jonathanj	(clojure.data.json/write {:some "fields"} (OutputStreamWriter. output-stream)) doesn't seem to actually write stuff
07:50	jonathanj	(.write output-stream "HELLO") appears to work fine
07:52	jonathanj	hrm, i guess i probably need to close the writer
07:52	jonathanj	(and use clojure.java.io/writer)
08:03	the_nonameguy	ashwin_: well then the decoder depends on the cookie encode, which you didn't state
08:04	the_nonameguy	if you do it yourself, the namespace containing the encoder usually contains the decoder as well
08:05	ashwin_	hmm
08:05	ashwin_	thanks I'll look into it
08:05	the_nonameguy	np
08:06	the_nonameguy	jonathanj: you possibly need to flush the buffer
09:12	jonathanj	hrm, is there any obvious way to convert https://pdfbox.apache.org/docs/2.0.0-SNAPSHOT/javadocs/org/apache/pdfbox/cos/COSDictionary.html to a Clojure map?
09:17	the_nonameguy	have you tried (into {} dict)?
09:19	jonathanj	yeah, it looks like that works, although i'm left with all these stupid java objects as keys and values
09:20	jonathanj	guess there's not really any way around writing a bunch of code to convert them
09:20	the_nonameguy	yeah, Clojure doesn't know how to turn Java classes into keywords :)
09:22	the_nonameguy	jonathanj: maybe this? http://clojure.github.io/clojure/clojure.core-api.html#clojure.core/bean
09:23	the_nonameguy	also checkout: http://blog.jayfields.com/2011/05/clojure-converting-java-object-to.html
11:07	beaky	http://www.thedotpost.com/2015/11/rob-pike-simplicity-is-complicated wow what a contrast to rich hickey's philosophy :D
11:12	jonathanj	holy crap, (bean) works magic
11:12	jonathanj	what the heck is a JavaBean?
11:14	sdegutis	Is it possible to make `cider-interrupt` cancel a ProcessBuilder's Process on the main thread?
11:14	sdegutis	That would rock you know.
11:15	jonathanj	interface{} everywhere definitely feels the opposite of simple
11:17	sdegutis	jonathanj: we talkin about Go?
11:19	jonathanj	sdegutis: beaky linked Rob Pike's talk on simplicity in Go
11:19	sdegutis	Heh.
11:19	sdegutis	Oh Rob Pike, you're such a character.
11:19	jonathanj	<beaky> http://www.thedotpost.com/2015/11/rob-pike-simplicity-is-complicated wow what a contrast to rich hickey's philosophy :D
11:28	beaky	btw how come logic programming hasnt taken over programming
11:28	beaky	like oop and fp have
11:28	beaky	i dont see scala or js bragging about 'wow we have a logic constraints engine baked into the stdlib now! :D'
11:29	beaky	instead its all about lambdas or mixins and classes
11:29	beaky	or some sort of concurrency paradigm
11:29	sdegutis	beaky: it aint easy
11:29	sdegutis	beaky: oop is easy
11:30	beaky	logic is pretty simple imo you just list a bunch of rules and the system figures out what you want
11:33	xemdetia	beaky, well there was those couple disasters in the 70s
11:33	xemdetia	or was it the 80s?
11:35	beaky	ah those disasters
11:36	beaky	idk isnt oop also a failed disaster in a way (what happened to all those 90s stuff like COM+ and CORBA)
11:36	xemdetia	yeah but then java happened
11:36	xemdetia	corba is more an interop thing that kind of works
11:36	beaky	ah
11:37	xemdetia	C++ was still hot too
11:37	xemdetia	logic programming never really had a C++ or Java level penetration
11:37	xemdetia	sounds like we need a rebranding!
11:37	xemdetia	because even if its the same thing called something different somehow this works
11:38	sdegutis	afaiui, C++ and Java were highly corporation-friendly because they allowed strong decoupling of system components, so that teams could work on it simultaneously
11:38	sdegutis	plus they had a low barrier to entry, being so unfortunately similar to what was taught in university
11:38	sdegutis	that's a recipe for large scale adoption
11:38	sdegutis	anyway im just guessing
11:39	xemdetia	so lets call it aool
11:39	xemdetia	agile object oriented logic
11:39	xemdetia	just enough buzzword soup
11:40	xaxes`	xemdetia: you forgot web-scale! everything has to be web-scale these days
11:41	xemdetia	xaxes`, but I thought that was yesterday's words
11:41	xemdetia	how about webscale 2.0
11:41	xemdetia	agile web scale oriented object logic 2.0
11:41	xemdetia	awsool
11:42	xemdetia	we're one vowel-prefixed word away from almost having something convenient to say and also under the dos filename limit!
11:42	xaxes`	we're closer to awesome
11:42	xaxes`	:D
11:44	gfredericks	, #_ #nope 42
11:44	clojurebot	#<RuntimeException java.lang.RuntimeException: No reader function for tag nope>
11:44	beaky	btw why cant you nest #()
11:44	gfredericks	beaky: the arg symbols would be ambiguous
11:44	beaky	ah
11:44	beaky	why not just have an extra % for each level deep :D
11:44	gfredericks	:P
11:45	gfredericks	that would make moving code around a pain
11:49	xaxes`	justin_smith: so, I have to (ns luthien.palantiri (:require [(file-load "path/to/plugin.clj") :refer [name-of-some-function-from-file]))?
12:01	seppo	hi
12:02	seppo	does anyone know how to require this library in clj file? https://clojars.org/org.clojars.nakkaya/jnativehook
12:04	devn	seppo: you can open up the jarfile and see which files exist in there
12:07	seppo	devn sure
12:07	keymone	is there a way to make read-string not evaluate anything?
12:08	seppo	keymone for which purpose are you using read-string
12:08	seppo	devn I opened the jar file. what's next?
12:09	keymone	seppo: i want to write a simple s-exp diffing program, need to read clj file into tree and compare that to another tree - don't care about correctness of stuff in those trees
12:13	fuuduCoder	i want to be able to pass a filter condition to distinct. https://clojuredocs.org/clojure.core/distinct
12:14	gfredericks	fuuduCoder: what would the filter do?
12:14	fuuduCoder	what would be the best way. i want to filter out distinct maps from a vector of maps using certain keys
12:15	gfredericks	seppo: for the most part read-string already doesn't evaluate anything
12:15	gfredericks	fuuduCoder: maybe try giving an example?
12:15	fuuduCoder	yeah. so for e.g [{:a 1 :b 1} {:a 2 :b 2} {:a 1 :b 2}] on filter key :a would give me [{:a 1 :b 1} {:a 2 :b 2}]
12:15	fuuduCoder	i ahte emoticons.
12:15	fuuduCoder	*hate
12:16	gfredericks	fuuduCoder: that sounds like something that doesn't exist in clojure called distinct-by
12:16	gfredericks	github.com/Prismatic/plumbing has it
12:16	fuuduCoder	yeah. so for e.g [{:a 1 :c 1} {:a 2 :c 2} {:a 1 :c 2}] on filter key :a would give me [{:a 1 :c 1} {:a 2 :c 2}]
12:17	gfredericks	fuuduCoder: a quick and dirty impl is
12:17	gfredericks	,(defn distinct-by [f coll] (->> coll (group-by f) (vals) (map first)))
12:17	clojurebot	#'sandbox/distinct-by
12:17	gfredericks	,(distinct-by :a [{:a 1 :c 1} {:a 2 :c 2} {:a 1 :c 2}])
12:17	clojurebot	({:a 1, :c 1} {:a 2, :c 2})
12:17	fuuduCoder	haha ..
12:17	gfredericks	not even all that dirty really
12:17	fuuduCoder	thats cool. but my map can get complex with multiple keys
12:18	gfredericks	so what would it mean to pass in multiple keys?
12:18	fuuduCoder	lets say keys :a and :b together would determine whether your map is unique or not
12:18	fuuduCoder	:a and :c
12:18	gfredericks	(juxt :a :c) would be your function then
12:18	gfredericks	,(distinct-by (juxt :a :c) [{:a 1 :c 1} {:a 2 :c 2} {:a 1 :c 2}])
12:18	clojurebot	({:a 1, :c 1} {:a 2, :c 2} {:a 1, :c 2})
12:19	fuuduCoder	let me try that.. seem spromising. thanks gfredericks
12:20	gfredericks	np
12:20	fuuduCoder	do you have functions at the tip of your mouth. i spent last 30 mins trying to figure out if there’s a useful function i could reuse
12:20	fuuduCoder	:-)
12:20	gfredericks	yes
12:30	fuuduCoder	gfredericks++
12:44	justin_smith	,(defn distinct-by' [f coll] (peek (reduce (fn [[found results] e] (let [index (f e)] (if (contains? found index) [found results] [(conj found index) (conj results e)]))) [#{} []] coll)))
12:44	clojurebot	#'sandbox/distinct-by'
12:44	justin_smith	,(distinct-by' (juxt :a :c) [{:a 1 :c 1} {:a 2 :c 2} {:a 1 :c 2}])
12:44	clojurebot	[{:a 1, :c 1} {:a 2, :c 2} {:a 1, :c 2}]
12:45	justin_smith	the (only?) advantage of my version is that with longer inputs the output would still be in order
12:55	gfredericks	oh yeah that's why it's dirty
13:37	JDShu	hi, does anybody have experience getting cider to work with maven?
13:38	justin_smith	JDShu: cider needs lein, and lein works well with maven
13:38	justin_smith	JDShu: are you trying to add deps at runtime? pallet / alembic makes that easy
13:39	JDShu	justin_smith: I'm working on a project that uses only maven and I'd like to use cider the same way I would with lein
13:39	justin_smith	JDShu: good luck, I think that would be a lot of work
13:41	JDShu	:( I'll try something else then - thanks though! good thing I asked here so I didn't end up spending a ton of time trying to do this
13:41	justin_smith	though I guess the main things you need are the same things that you would need to set up with boot https://github.com/boot-clj/boot/wiki/Cider-REPL
13:42	justin_smith	boot also doesn't use lein, so the instructions for making cider work with boot should be transferrable to a maven based project maybe?
13:42	justin_smith	the tricky part I guess is getting the right middleware injected for nrepl
13:43	amalloy	clojurebot: justin_smith is (paraphrased) boot is basically just maven
13:43	clojurebot	Ok.
13:43	justin_smith	umm....
13:43	justin_smith	amalloy: not quite what I meant
13:43	amalloy	well of course not, but what is the point of having factoid lookups for a person if not silly misquotes
13:44	justin_smith	haha, OK
13:45	JDShu	heh
13:45	JDShu	alright thanks, I'll give that a shot
13:46	justin_smith	I wouldn't be surprised if you could load some of boot from within a maven launched repl (but don't have proof it works either)
13:49	dxlr8r	anybody tried coils? web framework for clj
14:03	tolstoy	Is it possible, using leiningen, to use JDK8 to target JDK7 for an uberjar?
14:06	amalloy	tolstoy: yes, set the appropriate javac-otions
14:06	amalloy	see sample.project.clj
14:07	tolstoy	amalloy: Okay. It wasn't clear to me those options weren't just for the javac task. Thanks.
14:11	bendlas	tolstoy: they are just for the javac task, what else would you need to customize for targeting different jdks?
14:11	tolstoy	bendlas I want to build an uberjar with JDK8 to run on JDK7.
14:12	justin_smith	tolstoy: nothing in clojure itself targets jdks after 6
14:12	justin_smith	only the java compilation would do that
14:13	tolstoy	Ah, I'm getting java.lang.ClassNotFoundException: java.util.concurrent.CompletableFuture which must mean some lib or other I'm using deps on Java 8.
14:13	tolstoy	Or Oracle's JVM or something. Oy.
14:14	justin_smith	one of your deps must be trying to use that
14:14	bendlas	tolstoy: yes, ClassNotFound is a source code issue. If it were a target-jdk issue, you'd get some errors about invalid byte code versions or such
14:15	tolstoy	bendlas Yeah. I didn't even read the stack-trace when asking. Oops!
14:16	justin_smith	bendlas: "incompatible major/minor version...." iirc
14:16	tolstoy	And then it mentions 54. Or something like that.
14:16	bendlas	justin_smith: yes, I think YRC
14:29	jonathanj	(:a {} 42)
14:29	jonathanj	,(:a {} 42)
14:29	clojurebot	42
14:30	jonathanj	,({} :a 42)
14:30	clojurebot	42
14:30	jonathanj	hrm
14:30	justin_smith	,(:a 42 42)
14:30	clojurebot	42
14:30	jonathanj	i thought there was one of these forms that didn't support a default value
14:30	clojurebot	Titim gan éirí ort.
14:30	justin_smith	,(nth nil 42 42)
14:30	clojurebot	42
14:32	beaky	,(apply (partial apply +) [[1 2 3] [4 5 6] [7 8 9]])
14:32	clojurebot	#error {\n :cause "clojure.lang.PersistentVector cannot be cast to java.lang.Number"\n :via\n [{:type java.lang.ClassCastException\n :message "clojure.lang.PersistentVector cannot be cast to java.lang.Number"\n :at [clojure.lang.Numbers add "Numbers.java" 128]}]\n :trace\n [[clojure.lang.Numbers add "Numbers.java" 128]\n [clojure.core$_PLUS_ invokeStatic "core.clj" 962]\n [clojure.core$_PLUS...
14:32	beaky	:(
14:33	justin_smith	,(apply + (map (partial apply +) [[1 2 3] [4 5 6] [7 8 9]]))
14:34	clojurebot	45
14:34	jonathanj	i don't think there's any point trying to partially apply + without any arguments, it takes & args anyway
14:34	justin_smith	jonathanj: you need apply
14:34	jonathanj	(reduce + (flatten [[1 2 3] [4 5 6] [7 8 9]]))
14:34	jonathanj	,(reduce + (flatten [[1 2 3] [4 5 6] [7 8 9]]))
14:34	clojurebot	45
14:34	justin_smith	,flatten
14:34	clojurebot	#object[clojure.core$flatten 0x3ec68d46 "clojure.core$flatten@3ec68d46"]
14:34	justin_smith	~flatten
14:34	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.
14:34	justin_smith	jonathanj: flatten is the worst thing
14:34	justin_smith	,(flatten {:a 1 :b 2})
14:34	clojurebot	()
14:35	jonathanj	(reduce (partial apply +) [[1 2 3] [4 5 6] [7 8 9]])
14:35	jonathanj	,(reduce (partial apply +) [[1 2 3] [4 5 6] [7 8 9]])
14:35	clojurebot	#error {\n :cause "clojure.lang.PersistentVector cannot be cast to java.lang.Number"\n :via\n [{:type java.lang.ClassCastException\n :message "clojure.lang.PersistentVector cannot be cast to java.lang.Number"\n :at [clojure.lang.Numbers add "Numbers.java" 128]}]\n :trace\n [[clojure.lang.Numbers add "Numbers.java" 128]\n [clojure.core$_PLUS_ invokeStatic "core.clj" 962]\n [clojure.core$_PLUS...
14:35	jonathanj	oh, that's the same problem as originally
14:35	jonathanj	justin_smith: why does flatten even exist then?
14:35	justin_smith	it's a mistake, and it is still there for backward compatibility I guess
14:36	justin_smith	I take the urge to flatten something as a sign I have made a mistake in my design
14:36	justin_smith	usually mapcat suffices
14:36	jonathanj	i've never actually called (flatten) before, i've just seen the function
14:39	gfredericks	,(flatten {:a 1 :b [3]})
14:39	clojurebot	()
14:39	gfredericks	I guess it treats maps as scalars doesn't it
14:39	gfredericks	,(flatten [{:a 1 :b [3]}])
14:40	clojurebot	({:a 1, :b [3]})
14:40	justin_smith	gfredericks: yeah, same with strings and sets iirc
14:41	jonathanj	,(reduce (partial apply +) 0 [[1 2 3] [4 5 6] [7 8 9]])
14:41	clojurebot	45
14:42	gfredericks	the other use cases of flatten are solved better by tree-seq
14:43	gfredericks	,(tree-seq coll? seq {:a 1 :b [3]})
14:43	clojurebot	({:a 1, :b [3]} [:a 1] :a 1 [:b [3]] ...)
14:43	gfredericks	,(remove coll? (tree-seq coll? seq {:a 1 :b [3]}))
14:43	clojurebot	(:a 1 :b 3)
14:43	justin_smith	,(remove coll? (tree-seq coll? seq {:a 1 :b [3 "hello"]}))
14:43	clojurebot	(:a 1 :b 3 "hello")
14:44	justin_smith	interesting
14:44	gfredericks	it's customizable as hell
14:44	gfredericks	,(let [coll? (some-fn coll? string?)] (remove coll? (tree-seq coll? seq {:a 1 :b [3 "hello"]})))
14:44	clojurebot	(:a 1 :b 3 \h ...)
14:45	gfredericks	you could treat integers as collections of 1s if you wanted to
14:45	justin_smith	gfredericks: I still stand by flattening being a sign of either a bad design or a bad api (AKA someone else's bad design, but maybe you are stuck with it)
14:45	gfredericks	justin_smith: some things are treeful
14:50	justin_smith	gfredericks: hmm, I'll accept it as long as you name it "rake-leaves"
14:51	gfredericks	I think $ would be a good namespace for global mutable stuff
14:51	gfredericks	probably just repl-oriented
14:52	justin_smith	gfredericks: like how vinyasa does stuff?
14:52	gfredericks	maybe, I forgot that existed
14:54	gfredericks	woah this library is crazy
14:57	gfredericks	I wonder if he thought of the . namespace himself
15:26	jonathanj	is there a better way of spelling (- 0 n)?
15:28	matthavener	jonathanj: you can do (- n)
15:28	jonathanj	ah, thanks, i didn't even think to try that
15:30	jonathanj	has anyone used Graphics2D.rotate?
15:32	domokato_	in a macro, how do i get the namespace-qualified symbol of a passed-in symbol, for use in derive
15:32	domokato_	?
15:33	gfredericks	domokato_: I'm not sure if that problem is well-defined
15:34	gfredericks	domokato_: my guess is it'd be easier/cleaner to always have explicit namespaces anywhere you intend to use inheritance
15:35	domokato_	gfredericks: ah okay, that makes sense
15:37	Trioxin	I was surprised to not see any youtube vids on work in convolutional neural networks in clojure using opencl and/or cuda.
15:39	Trioxin	see libs in google though
15:40	domokato_	gfredericks: hm, in my macro i'm using the symbol to defrecord before using it in derive, which means I can't fully qualify it in the macro call since it doesn't exist yet
15:42	Trioxin	eh, https://github.com/whilo/nd4clj "Not really usable yet, as it is not compliant to core.matrix"
15:42	gfredericks	domokato_: symbols don't have to be "created", you can use any symbol anywhere anytime
15:43	gfredericks	,'my.ns.SomeDefRecord
15:43	clojurebot	my.ns.SomeDefRecord
15:43	gfredericks	domokato_: I'm starting to think you might be asking about something else
15:43	gfredericks	probably the class instead of the symbol
15:44	domokato_	,(doc derive)
15:44	clojurebot	"([tag parent] [h tag parent]); Establishes a parent/child relationship between parent and tag. Parent must be a namespace-qualified symbol or keyword and child can be either a namespace-qualified symbol or keyword or a class. h must be a hierarchy obtained from make-hierarchy, if not supplied defaults to, and modifies, the global hierarchy."
15:44	domokato_	i tried passing in the full symbol, org.aiinventions.aetherships.model/ShieldState, for example
15:44	domokato_	but i'm getting "java.lang.RuntimeException: Can't refer to qualified var that doesn't exist" at compile time
15:47	domokato_	,(defrecord sandbox/test-record [thing])
15:47	clojurebot	#error {\n :cause "Can't refer to qualified var that doesn't exist"\n :via\n [{:type clojure.lang.Compiler$CompilerException\n :message "java.lang.RuntimeException: Can't refer to qualified var that doesn't exist, compiling:(NO_SOURCE_PATH:0:0)"\n :at [clojure.lang.Compiler analyzeSeq "Compiler.java" 6891]}\n {:type java.lang.RuntimeException\n :message "Can't refer to qualified var that do...
15:48	domokato_	gfredericks: so it looks like i need a non-fully qualified symbol for defrecord but a fully qualified symbol for derive. not sure how to do that
16:07	gfredericks	domokato_: I think you're still confused about the difference between a symbol and a class, but I can't help any further right now
16:08	justin_smith	domokato_: what are you doing with derive?
16:09	domokato_	justin_smith: i'm trying to implement polymorphic records
16:10	justin_smith	so you are using multimethods on records, and using derive to describe their heirarchy?
16:10	domokato_	haven't gotten to the multimethods yet, but yes
16:10	justin_smith	records are already "polymorphic", they can hold any data type you like
16:10	jakedust	hi, what's the most idiomatic way to test unexported functions (unexported as in `defn-`)
16:11	justin_smith	jakedust: @#'the-ns/the-private-fn
16:11	domokato_	justin_smith: i mean records that can be extended by other records
16:12	justin_smith	domokato_: so you want multimethod dispatch to find defaults based on some other more general record type?
16:12	jakedust	justin_smith: thanks! what's the difference between derefing it and not derefing it? both ways seem to work
16:12	justin_smith	because records don't do field inheritence or protocols or interface inheritence
16:13	justin_smith	jakedust: #'foo when called does an automatic deref
16:13	jakedust	oh, I see, thanks!
16:13	justin_smith	jakedust: but if you are using a value, you need the explicit @, so it's good to get in the habit
16:13	justin_smith	the calling case is special and the @ is optional then
16:15	domokato_	justin_smith: not sure what you mean by defaults. My "super records" are just lists of fields and don't have an actual class. When a record extends a super record, i just conj those super fields and put them in the defrecord call
16:15	justin_smith	so you are rolling your own inheritence by hand
16:15	domokato_	yep
16:16	domokato_	i have different records that share a sprite field, for example, and i'd like to be able to get the sprite field out of all of them without having to switch on the type
16:16	justin_smith	domokato_: (map :sprite coll-of-heterogenous-records)
16:17	domokato_	i'm using records because keyword access to records is slow for some reason
16:17	domokato_	er
16:17	domokato_	.field
16:18	justin_smith	#(.field %) then ?
16:18	hiredman	it is slow because you have many different types so you are blowing the catch
16:18	hiredman	cache
16:18	domokato_	justin_smith: doesn't that need to be type hinted to avoid reflection?
16:19	domokato_	hiredman: oh, i didn't know that. but in my case there's not really a way around that, or is there?
16:19	hiredman	why aren't you using a single record type if they all have the same field?
16:20	hiredman	if you do keep them as distinct records, use a protocol
16:20	domokato_	hiredman: because they have different fields in addition to that shared field. A ship has a sprite and a pilot, etc.. A bullet has a sprite and a lifespan
16:21	hiredman	use a protocol
16:22	domokato_	hiredman: use a protocol in what way?
16:22	hiredman	(defprotocol IHaveASprite (get-sprite [thing-with-a-sprite]))
16:23	justin_smith	agreed, if you find keyword lookup too slow, you won't like multimethod dispatch time
16:23	hiredman	extend the protocol to the records inline in your defrecords
16:23	domokato_	hiredman: also, going back to what you said before. are you saying if i process all of my ships in order, then all of my bullets, etc, i won't blow the cache and it'll be much faster?
16:24	hiredman	domokato_: no, the cache is monomorphic if I recall
16:24	hiredman	once you start having different types going through callsite performance will tank
16:25	hiredman	that is the case in generally for exverything on the jvm
16:26	hiredman	an inline defprotocol on the jvm actually works around that (because everything that implements the protocol inline shares an interface)
16:27	hiredman	so instead of having a bunch of types which, as far as the jvm and the jit knows, having nothing to do with each other, you get a bunch of types that the jits knows share some structure
16:31	domokato_	hiredman: okay! i think i got it
16:31	domokato_	hiredman: for a second i forgot defrecord can extend protocols
16:32	domokato_	thx hiredman and justin_smith
16:42	hibou	,(map #(apply + %) (map list '(1 2 3) (rest '(1 2 3))))
16:42	clojurebot	(3 5)
16:42	hibou	is there any better way to do that ?
16:42	justin_smith	,(map + '(1 2 3) (rest '(1 2 3)))
16:42	clojurebot	(3 5)
16:42	hibou	yes of course thanks justin_smith
16:43	gfredericks	,(->> '(1 2 3) (partition 2 1) (map #(apply + %)))
16:43	clojurebot	(3 5)
16:43	gfredericks	nah justin_smith's is better
16:43	justin_smith	yours is more clever though
16:52	gfredericks	no way man
16:57	didibus	I'm calling into a java method, but Clojure seems to be selecting the wrong overload. I've tried to type hint, but I'm not sure how to do so it can pick the right overload
16:58	gfredericks	didibus: does warn-on-reflection still give you reflection warnings?
16:58	justin_smith	didibus: is it varargs? varargs methods from clojure are a bit weird
17:01	hiredman	didibus: why do you think it is picking the wrong overload?
17:01	didibus	Hum, actually, it might be my fault.
17:01	didibus	I think I might just have the signature wrong
17:08	WorldsEndless	Any ideas why my repl tells me "Please, install (or update) cider-nrepl 0.10.0 and restart CIDER" when I'm using today's package?
17:12	codahale	WorldsEndless: CIDER 0.10 was released today.
17:12	WorldsEndless	Right. And I'm using it (was using snapshot before)
17:12	WorldsEndless	The start of that message, before it starts warning about all the unspported nREPL ops, is:
17:12	WorldsEndless	; CIDER 0.10.0 (package: 20151203.822) (Java 1.8.0_65, Clojure 1.7.0, nREPL 0.2.12)
17:13	codahale	Odd. No idea, sorry.
17:16	hibou	http://paste.ofcode.org/JbLWDZqqVRs287ReQESUFL
17:17	hibou	I got the error java.lang.ArithmeticException: integer overflow
17:17	hibou	in the last test https://www.4clojure.com/problem/132
17:18	gfredericks	hibou: looks like that means your function isn't lazy
17:18	gfredericks	hibou: the sequence created in that test throws that exception if you consume too much of it
17:18	hibou	because I used that zip (map list l (rest l)) ?
17:19	gfredericks	not sure, I didn't look at your code much after I didn't find any arithmetic there
17:19	hibou	when I do a (rest l) then my code is not lazy anymore ?
17:20	gfredericks	hibou: I suspect it's because you're using recur, which is eager
17:32	pvinis	hello. i wanna test all the things in a vector, without having many `(is (somefn item))`
17:32	pvinis	can i do that?
17:32	gfredericks	doseq
17:32	gfredericks	(doseq [item items] (is (somefn item)))
17:32	pvinis	aha
17:32	pvinis	awesome. thanks
17:44	kenrestivo	i love destructuring. makes code so much cleaner and concise
18:11	MONODA	I'm using cursive and intellij to debug some code but in order for my repl session to see the changes I make I need to restart the repl and start over again. any ideas why?
18:11	cfleming	MONODA: What sort of changes are you making?
18:12	MONODA	I'm writing the matrix library protocols for my matrix implementation
18:12	justin_smith	MONODA: higher order functions won't see new definitions for your defs / defns unless you re-run them
18:12	justin_smith	that's a common gotcha
18:13	MONODA	How do I rerun the defs? I thought I was doing that when I synced the current file with the repl
18:13	justin_smith	MONODA: oh, yeah, protocols are not very nice about reloads
18:13	MONODA	hmm ok... any workarounds?
18:13	justin_smith	you can make the protocol method call a def - then changing the def will update what the protocol does
18:14	justin_smith	but you would want to move it back from the def into the protocol when done debugging - you lose performance when you move it out to a def
18:14	MONODA	sounds easy enough
18:14	MONODA	thanks
18:15	alive876_	i, could anyone take a look at my project.clj file, getting loading error http://pastebin.com/DdTmryNL much thanks!
18:15	MONODA	Im also having another problem where I get a stack overflow when I run some buggy code and then the repl starts acting weird until i reset
18:15	MONODA	is that expected? any solutions other than restarting repl session?
18:16	cfleming	MONODA: What do you mean by acting weird?
18:17	MONODA	it will only respond with "stack overflow" until i restart it
18:17	MONODA	but there are some functions I can call and it will respond as expected
18:18	cfleming	Is the loop in the stacktrace in your code, or in something else? It sounds like your buggy code is hanging around and being called somehow.
18:19	MONODA	im not sure, would I just check that with (pst) ?
18:20	cfleming	Yeah, or you can use the button in the Cursive REPL window to print the last exception
18:20	MONODA	so how would I kill my buggy code?
18:27	justin_smith	MONODA: is it happening in a thread somewhere?
18:27	MONODA	no im not doing any concurrency
18:28	justin_smith	then I don't see how the errors are repeating if you have a repl prompt...
18:49	pvinis	i want to chck if numbers in a seq are continious, is that close? `(reduce (fn [a b] (= (inc a) b)) (list 4 5 6))`
18:49	j-pb_	monotonic, or really off by one?
18:50	pvinis	by one
18:50	justin_smith	pvinis: that won't work because you need to return the previous item
18:50	pvinis	456 is true, 356 is false
18:50	pvinis	could you point me to the correct function?
18:50	pvinis	maybe with doseq?
18:51	justin_smith	(every? #(= 1 %) (map - (rest coll) coll))
18:51	j-pb_	(= s (range (first s) (inc (last s)))
18:52	justin_smith	j-pb_: oh, that's a good one
18:52	pvinis	ok, i have to try them to understand
18:52	pvinis	one sec
18:52	j-pb_	missing paren in my one, add one to the end ;D
18:53	j-pb_	probably not the most efficient one, since last is O(n)
18:54	justin_smith	(every? (map = s (range s Integer/MAX_VALUE)))
18:54	pvinis	j-pb_: ah cool! so you make the range from the first, and just cheeck if same
18:54	pvinis	interesting..
18:54	j-pb_	justin_smith: nice even better :D
18:55	pvinis	justin_smith: trying yours now
18:55	justin_smith	pvinis: I think every? might be missing an arg there
18:56	pvinis	the first one is fine
18:57	pvinis	yea, the second one is complaining
19:02	pvinis	(every? (fn [[a b]] (= (inc a) b)) (partition 2 1 s))
19:02	pvinis	someone on slack offered this..
19:03	pvinis	partition with step works interestingly too
19:05	domokato	justin_smith, hiredman: it works! extensible records! http://pastebin.com/Xw796bk3 one level deep at least
19:07	j-pb	(= (rest s) (butlast (map inc s)))
19:10	pvinis	j-pb: is butlast faster?
19:10	pvinis	isnt it same as last?
19:10	justin_smith	pvinis: butlast is all elements but the last
19:11	j-pb	nope
19:11	pvinis	yea. so to get that, itsnt it O(n) again?
19:11	j-pb	yeah
19:11	pvinis	oh linear time says the doc
19:11	pvinis	cool
19:12	pvinis	last is also linear..
19:12	j-pb	(or how about this
19:12	pvinis	what was O(n) that you said before?
19:12	j-pb	(apply = true (map = s (range (first s))))
19:12	j-pb	last
19:13	pvinis	omg the one with butlast is magic!
19:13	justin_smith	(every? true? (map = s (range (first s)))
19:14	j-pb	(every? true? (map = s (iterate inc (first s)))
19:14	justin_smith	j-pb: that won't work actually - first is is used as the upper limit
19:14	justin_smith	right
19:14	j-pb	doesn't have chunking though so slower
19:14	j-pb	yeah
19:14	justin_smith	or (range (first s) Integer/MAX_VALUE)
19:14	pvinis	my brain = mush
19:14	j-pb	yeah but dat max_val D:
19:15	j-pb	;D
19:15	j-pb	but has chunking so thats nice
19:15	j-pb	I wonder, does inc autoconvert to bignums once it hits the limit?
19:15	justin_smith	j-pb: it stops when the shorter collection runs out
19:15	justin_smith	j-pb: nope, but inc' does
19:15	justin_smith	,(doc inc')
19:15	clojurebot	"([x]); Returns a number one greater than num. Supports arbitrary precision. See also: inc"
19:15	j-pb	noice
19:15	j-pb	,(doc inc")
19:15	clojurebot	#<RuntimeException java.lang.RuntimeException: EOF while reading string>
19:16	justin_smith	,(inc' Long/MAX_VALUE)
19:16	clojurebot	9223372036854775808N
19:16	justin_smith	,(inc Long/MAX_VALUE)
19:16	clojurebot	#error {\n :cause "integer overflow"\n :via\n [{:type java.lang.ArithmeticException\n :message "integer overflow"\n :at [clojure.lang.Numbers throwIntOverflow "Numbers.java" 1501]}]\n :trace\n [[clojure.lang.Numbers throwIntOverflow "Numbers.java" 1501]\n [clojure.lang.Numbers inc "Numbers.java" 1839]\n [sandbox$eval93 invokeStatic "NO_SOURCE_FILE" 0]\n [sandbox$eval93 invoke "NO_SOURCE_FIL...
19:16	j-pb	ah, you never stop learning
19:17	irctc	Hi all. :)
19:17	j-pb	oi
19:17	pvinis	ok tried the apply one, and the too every
19:17	pvinis	only this worked
19:17	pvinis	(every? true? (map = s (iterate inc (first s)))
19:17	j-pb	yeah, I used range wrong
19:18	justin_smith	(every? true? (map = s (range (first s) Integer/MAX_VALUE)))
19:18	pvinis	,(inc" Long/MAX_VALUE)
19:18	clojurebot	#<RuntimeException java.lang.RuntimeException: EOF while reading string>
19:18	justin_smith	pvinis: not inc", but inc'
19:19	irctc	Instead of printing output how do I save the output from this code to a separate variable outside the go block? (go (while true (println (<! c))))
19:19	j-pb	irctc: atom
19:19	irctc	j-pb: I am completely unfamiliar with atoms, xould you please explain?
19:20	pvinis	but j-pb and justin_smith, nice solutions. creative
19:20	j-pb	irctc: however, this will probably negate many of the advantages of core async, so data should be passed around through channels whenever possible
19:20	pvinis	i wrote them down so i can check them out again later
19:20	pvinis	thank you :D
19:21	irctc	j-pb: well now I get data really fast just printed to stdout. Instead of that I want that data to be saved in a collection in some variable.
19:21	j-pb	irctc: what do you want to do? clojure doesn't really have variables, and assigning the value to something in the scope around the go block doesn't really make sense because of the while true
19:21	j-pb	so you can later look at the values?
19:21	j-pb	(def events (atom [])
19:21	irctc	Well, I just want to put the data returned from my async calls to a {}.
19:22	irctc	Yes.
19:22	j-pb	(go (while true (swap! events conj (<! c))))
19:22	j-pb	that puts them into the events atom
19:22	j-pb	but what do you want to do with that data?
19:23	j-pb	I mean, putting it into the atom, doesn't nessecarily make it accessible
19:23	j-pb	I mean, you need to get at it from some context right?
19:23	irctc	Well, I want to later process that data in other functions.
19:23	j-pb	pvinis: np, thanks for the nice riddle :D
19:24	j-pb	irctc: why not pass that data to the processing functions via channels?
19:24	pvinis	:)
19:24	irctc	j-pb: How do I do that?
19:24	j-pb	irctc: alternatively you could do something like this if you just want to store the messages locally in the go loop
19:25	j-pb	(go (loop [e (<! c)])))
19:25	j-pb	urgh sorrry
19:26	j-pb	(go (loop [e (<! c)
19:26	j-pb	acc []]
19:26	j-pb	(recur (<! c) (conj acc e))))
19:26	irctc	I know about the lets, and I tried that and it works, but outside the scope of the go block I can't access those bindings. I need to be able to access the results outside the go block.
19:26	j-pb	why?
19:26	clojurebot	why not?
19:27	j-pb	why not put the processing in other go blocks?
19:27	justin_smith	j-pb: if you exit the loop, the channel returned by the go block will be able to read whatever you returned from that loop
19:27	j-pb	the above is an example of a statefull goroutine btw
19:28	j-pb	justin_smith: yeah sure, but if you have while true in there, then you never exit from it
19:28	justin_smith	j-pb: oh wait, you probably know that, and irctc was asking, never mind
19:28	irctc	Well, I have five calls to the same function with different data that need to happen simultaneously so that's why I'm using async. This processes the whole lot a lot faster. So far I can print the results but I want the results to be saved in a map so that I can use them later.
19:28	j-pb	irctc: honest suggestion, use futures
19:29	irctc	I need the while true to read the data as it is being fed into the channel.
19:29	j-pb	core async is great for coordination, but not that great for parralel computation
19:29	j-pb	if you just want more performance, I'd suggest
19:29	j-pb	pmap for example
19:29	j-pb	or if you want to do something 5 times on the same data
19:29	justin_smith	irctc: looping infinitely is incompatible with returning a result
19:29	justin_smith	~pmap
19:29	clojurebot	pmap is not what you want
19:30	irctc	So how do I create a loop that continually checks wether I have something in my channel that needs to be taken out?
19:30	justin_smith	irctc: loop while the channel is open, close the channel when done feeding it
19:30	j-pb	(let [r1 (future (expensive computation))
19:30	j-pb	r2 (future (expensive computation2))
19:30	j-pb	r3 (future (expensive computation3))
19:30	j-pb	[@r1 @r2 @r3])
19:30	justin_smith	or use a special :finished value
19:30	j-pb	will do r1 r2 and r3 in parralel
19:32	j-pb	unless you have a huge amount of coordination, core.async is usually not what you want
19:32	j-pb	hell I just wrote a kafka inspirte persistent log for clojurescript so that I don't have to use the core.async sausage machine
19:33	j-pb	irctc: so yeah, if you
19:34	irctc	j-pb: so what you're saying is that there is no way I can do this with core.async?
19:34	j-pb	're new to clojure, learn about futures and pmap first, to speed things up
19:34	j-pb	irctc: I'm not saying there is no way
19:34	j-pb	I'm just saying it might not be the best option
19:34	j-pb	what is your scenario?
19:34	j-pb	you get data in?
19:35	j-pb	and you want to do different things on it in parralel?
19:35	irctc	yes
19:36	j-pb	and what do you want to do with the results?, just keep them?
19:36	j-pb	what do you want to do in parralel?
19:36	irctc	What is that website where I can quickly paste code to show you what I'm up to?
19:36	j-pb	gist
19:36	j-pb	pastebin
19:38	irctc	http://pastebin.com/M4H0ypw6
19:38	irctc	That's my function.
19:39	j-pb	where does in-chan come from?
19:39	irctc	Now if instead of conj take-ipnut I just put println, it prints out the results really quickly. But as soon as I try to conj to take-input I get nil returned and take-input remains empty.
19:40	irctc	It's defined outside and it's allready filled with data to be processed.
19:40	j-pb	filled by what?
19:40	j-pb	can you show me?
19:41	irctc	Sure it's a map of key-value pairs.
19:41	j-pb	no no :), not with what, by what ^^
19:41	j-pb	how do you fill it
19:42	irctc	I have a function that generates the data when it's called.
19:42	j-pb	can you show me the code where you put it in in-chan :)
19:43	irctc	http://pastebin.com/DKSpSwr1
19:44	irctc	And stdin-reader is where the data is stored to be put in in-chan.
19:44	j-pb	and the content of stdin-reader is finite?
19:44	j-pb	or an infinite stream?
19:44	irctc	Yes, it's finite.
19:44	j-pb	small enough to hold it in memory?
19:44	irctc	Yes.
19:45	j-pb	(pmap (fn [line] (create-ratings api-key line)) stdin-reader)
19:45	j-pb	does exactly what you want
19:45	j-pb	except that it automatically chooses the right amount of threads for maximum performance
19:46	j-pb	and would generally faster than core.async I think because of less locking/sheduling overhead
19:48	j-pb	on a side node, when you close the channel you can dump all it's contents into a collection with into
19:48	j-pb	but don't do this
19:48	j-pb	use pmap
19:49	irctc	j-pb: Thank you a thousand times!!!! :D
19:49	j-pb	most welcome :)
19:49	irctc	It does exactly what I needed it to do! :D
19:50	irctc	I really appreciate your help. :)
19:50	j-pb	no worries, glad I could :)
19:50	j-pb	core.async is cool tech, but the most powerfull stuff is the simple things in the std lib :D
19:56	kenrestivo	i'm trying to use a library that uses JSR47 for logging, with timbre. how much pain and suffering will i have to endure to get that to happen?
20:02	pvinis	good night all
20:03	j-pb	night :)
20:11	irctc	Good night everyone!
20:15	MONODA	I'm writing a recursive protocol, how can I be sure that I am calling my new protocol rather than the protocol written for another datatype?
20:16	MONODA	I'm getting a type error so i guess clojure doesnt know about my new implementation?
21:01	kenrestivo	no love for jsr47, eh?
21:04	kenrestivo	hmm, i guess this jsr47 thing uses java.util.logging as a back-end. so now i just have to figure out how to grab those messages and get them into timbre, i guess? this java logging thing is... complected.
21:59	krabador	https://www.youtube.com/watch?v=CdPn1mCmqoE