#clojure – 2016-02-22

2016-02-22

03:50	CStorm	how do i set a environment variable on unbuntu which environ can get? ive tried putting it in /etc/environment but no luck.
04:49	hyPiRion	CStorm: You probably need to restart/logout then login again for it to be reflected
05:53	Kah0ona	solatis: I'm currently working on a nice green-field freelance solo project for a company in Tilburg until like May-June, but when it's done, we probably need to talk ;-) (I'm Dutch, freelancer, Den Haag based.)
05:54	Kah0ona	(if i read correctly that you are hiring that is)
05:54	Kah0ona	kinda skimmed over the cats discussion
05:55	Kah0ona	I have two cats too ;-)
05:56	Kah0ona	Anyway; in summer I have another fairly large clj project added to my portfolio. working on it now
06:06	TEttinger	haha
06:06	TEttinger	cats
07:13	aurelian	hi there... what's the idea with lein creating an empty folder called dev-resources ?
07:13	aurelian	how do I get rid of it?
07:16	ridcully	{:profiles {:dev {:resource-paths set?
07:17	aurelian	doesn't look like
07:17	aurelian	:profiles {:uberjar {:aot :all}})
07:17	aurelian	it's a standard lein new project
07:17	aurelian	using app template or wtv the default is
07:18	aurelian	oh. upgraded lein and now is gone.
07:18	aurelian	mind me
07:19	aurelian	I was on 2.5.something
07:37	hyPiRion	aurelian: yeah, sorry about the empty folders. They should be gone with 2.6.x
07:37	aurelian	it's ok, thanks!
07:37	aurelian	confirmed they're gone
07:58	timvisher	i'm logging from a background thread that updates an atom that i dereference. everytime i dereference the atom a log message comes out but if i don't dereference the atom no message comes out. is there any way i can force those exceptions to be logged without having to dereference the atom?
08:21	TimMc	timvisher: Dereferencing an atom should not cause side effects. Do you have lazy seqs or something in there?
08:26	timvisher	laziness…
08:26	TimMc	~laziness
08:26	clojurebot	laziness means not traversing anything twice
08:26	TimMc	~laziness
08:26	clojurebot	laziness means not traversing anything twice
08:26	TimMc	oh well
08:27	TimMc	timvisher: So yeah, sounds like you need a dorun or doall in there somewhere. :-)
08:27	timvisher	anyway yeah. one `map → mapv` transformation later and boom
08:39	TimMc	Could I get some advice/rubber ducks on a concurrency mechanism for serializing writes to a cache?
08:40	TimMc	The code is currently sending ~50 writes per second (luxuriously few, given that writes are 1-2 ms) and I was thinking of just dumping them into a dropping or sliding queue and spinning a thread to pick them up at the other end and put them in the cache.
08:42	TimMc	I'm thinking simple 'n' robust is better, because we rely on the cache being up, and if we stop updating it, there's going to be trouble.
08:42	TimMc	Any constructs I should be looking at in particular?
08:47	TimMc	Agents are out, as usual. I've never ended up finding a good use for them.
08:50	jamesturnbull	hi all - I have a collection [var1 var2] that I am trying to join. var2 may sometimes be nil. I want to ensure a separater is present if there are two elements but not if there is one. (clojure/string.join "." [var1 var2]) becomes var1. if var2 is nil.
08:50	hyPiRion	TimMc: I think just a Thread and a BlockingQueue would work fine. Then you can use .offer to insert values which may be dropped.
08:50	hyPiRion	I am no guru on concurrency mechanisms though
08:50	TimMc	And just a try/catch in the thread is probably sufficient to make sure it never dies?
08:51	TimMc	I'll monitor the length of the queue, of course.
08:51	hyPiRion	Yeah.
08:51	TimMc	hmm, also need shutdown mechanism
08:51	TimMc	Channels feel like maybe they're relevant here, although I hesitate to introduce yet another concurrency mechanism or structuring principle to this codebase...
08:54	hyPiRion	TimMc: It depends on how you'd like to shut down. I like to just use .interrupt and catch InterruptExceptions
08:59	TimMc	hiredman: That... sounds perfectly reasonable, actually.
08:59	TimMc	oops
08:59	TimMc	hyPiRion, rather
09:01	TimMc	jamesturnbull: They're both strings already?
09:03	TimMc	I'd probably go with something simple like (cond-> (str v1) v2 (str "." v2))
09:03	jamesturnbull	TimMc: yeah both strings. thanks will try that!
09:04	TimMc	(that handles them not being strings, but not if v2 can legitimately be the boolean false)
09:04	dysfun	what's the function called that turns '_BANG_' etc. into '!' in a name?
09:04	TimMc	demunge?
09:04	dysfun	that's the one, ta
09:04	TimMc	but I think it's only in clojure.repl
09:05	TimMc	and has a bug, IIRC
09:05	dysfun	that's acceptable for this, this module is meant for during development
09:05	dysfun	oh :/
09:05	TimMc	something about double underscores
09:06	dysfun	haha, and the literal word 'BANG' probably
09:07	TimMc	hmm, I think I'm thinking of a bug in pst around extracting munged fn names
09:13	jamesturnbull	TimMc: thanks - works perfectly - didn't know about cond-> - neat.
09:15	dysfun	TimMc: so demunge is fine?
09:15	dysfun	(to the best of your knowledge)
09:16	TimMc	dysfun: Yeah, and I found the original (fixed) bug: http://dev.clojure.org/jira/browse/CLJ-1083
09:17	dysfun	aha
09:18	dysfun	of course if you're a java programmer and you're writing _BANG_, you need your head looking at
09:20	ridcully	static final String LOL_BANG_LOL seems not so far out that head inspection is needed? ;P
09:20	TimMc	Probably true, but that kind of argument never sits well with me.
09:22	TimMc	This is why we have problems like not having any way to escape characters in a <script> block in HTML. "Just don't write </script> in your script, ever, OK?" Fast forward a decade and we've got user data being plunked down in JSON into script blocks and no end of trouble.
09:22	TimMc	Universality is good for security and correctness.
09:23	TimMc	(I gave a talk on this at work. I should turn it into a blog post.)
09:24	dysfun	i'd read it
11:27	justin_smith	TimMc: agents are when you want a mutable container and retries on update are out of the question
11:28	justin_smith	(in my experience, they probably also have other uses)
11:28	justin_smith	TimMc: as such they are the only clojure mutable container that it's safe to put actual mutable objects inside
11:31	sineer	Hi! if I have a (let [foo "bar"] (if foo (let [foo "baz"]))) is there a nicer way to reassign my foo var without requiring yet another let?
11:31	justin_smith	,(let [foo "bar" foo (if foo "baz" foo)] foo) ; sineer
11:32	clojurebot	"baz"
11:32	justin_smith	sineer: and it is not "reassigning" anythign, it's shadowing
11:32	justin_smith	but that's good enough (unless a previous binding used the value, then it's clear it was just shadowing)
11:33	sineer	right (about shadowing). it feels wierd... I'll try it
11:33	justin_smith	sineer: it's the same thing the nested let would do
11:33	Bronsa	justin_smith: care to expand on "agents are the only clojure container that it's safe to put mutable object inside"?
11:34	justin_smith	Bronsa: no retries
11:34	justin_smith	retries fuck with mutable things
11:34	Bronsa	ah, gotcha
11:34	justin_smith	I mean yeah you could put a mutable thing inside and promise not to mutate it in swap! or alter calls...
11:34	Bronsa	I'd feel so safe doing that
11:36	justin_smith	oh, there's vars too of course
11:36	justin_smith	but that's only for top level things
11:36	justin_smith	so for example when I use stuartsierra/component I put my system inside a var or an agent (neither retries) instead of an atom or ref
11:57	TimMc	If the actions on the mutable thing are idempotent it might be OK.
12:01	justin_smith	TimMc: sure, maybe, but still, if what you have is a thing containing maybe some clojure data and some mutable stuff that isn't concurrency safe that you need to punch in unsafe ways, agents are a decent way to manage that state
12:01	justin_smith	because the actions sent are guaranteed to be one at a time, no retries, etc.
12:02	justin_smith	simpler than wrangling locks anyway
12:06	TimMc	justin_smith: What's an example of something you've used an agent for?
12:07	justin_smith	TimMc: stuartsierra/component system object (I don't want retries just because something else tried to start it)
12:08	justin_smith	TimMc: various cases where I was using core.async but realized all I needed was one queue and I could send it functions
12:09	justin_smith	and I would use it if I needed to use a mutable object unsafe for concurrency that had namespace level scope, but that hasn't come up remarkably
12:10	TimMc	hmm
12:13	justin_smith	TimMc: if you have a simpler solution for those cases feel free to offer, of course
12:17	justin_smith	of course the canonical thing with a component is a var, but that doesn't cover overlapping calls as nicely I don't think?
12:20	justin_smith	actually I can't tell if this retries or not? https://github.com/clojure/clojure/blob/master/src/jvm/clojure/lang/Var.java#L302
12:25	sineer	clojure.lang.ExceptionInfo: Cannot recur accross try ... I can't try/catch inside a go loop if I must recur ?
12:25	justin_smith	sineer: you need to move the try/catch to not surround the recur
12:25	justin_smith	sometimes this requires a promise or delay for the value propagation to work (sadly)
12:26	sineer	so inside the go block but before the (loop ) ?
12:26	sineer	otherwise if it's outside the go block then it won't work correct?
12:26	justin_smith	or inside the loop but not surrounding the recur
12:26	justin_smith	depends what needs catching
12:27	justin_smith	sineer: (loop [x 1] (let [res (promise)] (try .... (deliver res v) ... (catch ... (deliver res nil)) (recur @res)) ; if you need to use a value created inside the try in your recur
12:28	justin_smith	if you don't need to use any value from inside the try in your recur call, that's much simpler of course
12:28	sineer	k, thanks!
12:31	justin_smith	sineer: actually there should probably be a deliver in the finally clause in the above, to guarantee you don't do a blocking deref that won't be fulfilled inside the recur call
15:04	mping	hi guys
15:27	gfredericks	I need some names for things in test.check
15:27	TimMc	fred
15:27	gfredericks	to be more specific
15:27	AimHere	fred smith
15:28	TimMc	the third
15:28	gfredericks	I need to differentiate a test run from a single trial
15:28	gfredericks	but "test run" sounds too much like running your whole test suite
15:28	gfredericks	I don't know which of the two "trial" sounds like
15:28	{blake}	"single trial" seems pretty clear
15:28	gfredericks	this is for things to go under the :type key in a map passed to a callback function to let you know what's going on
15:29	gfredericks	so event names I guess
15:29	gfredericks	maybe :start-test, :trial, :end-test, that sort of thing
15:29	gfredericks	i.e. I think "test" is a decent name for the larger chunk of work
15:29	gfredericks	GREAT thanks everybody
15:30	gfredericks	cfleming: hi
15:50	TimMc	gfredericks: Yes, trial sounds right.
15:50	TimMc	or even probe, but trial is better
15:50	TimMc	chcek :-P
15:50	TimMc	*check
15:51	gfredericks	naming is one of the 94 hard problems in computer science, along with cache-invalidation and off-by-91-errors
15:52	TimMc	*71
16:10	andyf	I know a gentleman from India whose last name is "Furniturewala". Yes, the English word "furniture" followed by "wala", with no space.
16:11	andyf	"wala" means "maker", so he is named for one of his recent ancestors being a furniture maker, after English was reasonably common in India, but before surnames were common, so the surname was created after that.
16:12	andyf	That was one of my top all time favorite names, until this weekend, when I heard a similar but even more awesome name: "Sodabottleopenerwala"
16:12	andyf	I am not joking
16:15	andyf	Sorry, no application to your naming question, gfredericks, although I would suggest putting 'wala' in constructor names whenever you can :-)
16:16	justin_smith	andyf: beats Factory for sure
16:16	zipper	Hey guys, I need some clojurescript help. I can get it here, right?
16:17	andyf	If all planets line up properly, then yes.
16:17	hiredman	maybe, depending on the nature of the help required, there is a #clojurescript channel I think too
16:18	gfredericks	~andyf is a walanamewala
16:18	clojurebot	Ik begrijp
16:19	{blake}	A propos of which, I'm having reagent timing issues.
16:19	{blake}	I have a reagaent component that renders a table full of controls.
16:19	{blake}	After rendering, I want to attach some Jquery to the controls.
16:20	{blake}	I dutifully used with-meta and :component-did-mount, which I wrapped my rendering function around.
16:20	{blake}	The code is called. I know, because it starts a timer.
16:20	{blake}	But the attempt to collect all the controls of a class fails. (I'm collecting, e.g., currency controls to apply MaskMoney to.)
16:21	{blake}	If I put the collection code into the timer code, it works, I presume because that stuff fires long enough for everything to have settled.
16:21	{blake}	er, late enough
16:21	amalloy	MaskMoney is the account bruce wayne sets aside for batman-related activities
16:22	{blake}	And I suppose I could create a timer event to fire JUST to set this Jquery code. But that seems cheesy, and wrong.
16:22	{blake}	He must go through masks like crazy.
16:23	amalloy	fwiw andyf, we have lots of names like that in english already, we're just used to them because we've had them so long
16:24	amalloy	plenty of masons, smiths, thatchers, coppersmiths, and so on
16:24	gfredericks	andyf: the clear conclusion is that you need to come to clojure/west this year
16:24	hiredman	{blake}: sounds like you need the js equiv of swing's invokeLater, which I guess would be a zero second settimeout
16:25	{blake}	hiredman: Mebbe. It's gotta exist. No way people =aren't= doing this exact thing. But it can be hard to find info.
16:25	{blake}	(Or in this case, figure out where I've gone wrong, because if :component-did-mount isn't for this, what IS it for?)
16:27	hiredman	https://facebook.github.io/react/docs/component-specs.html#mounting-componentdidmount it does sone like that is what it is for
16:27	hiredman	sound
16:27	{blake}	Hmmm. Immediately after initial rendering occurs.
16:27	andyf	gfredericks: The thing I found interesting was the combination of words from two languages in a single name.
16:27	zipper	So since the clojurescript channel isn't full of life. I will ask here too.
16:28	zipper	So in this code https://www.refheap.com/115084#L-2 The Line 2 fails. I am trying to rewrite whatever is from L12 since that regex fails to work for () and \|
16:28	andyf	gfredericks: Kids still in college, and on top of that there is big hardware/software product release coming up this April, but maybe the hubbub will be over by the Conj.
16:29	hiredman	zipper: you are qouting the regex and not the list
16:30	hiredman	zipper: so you are invoking the regex as a 0 arg function, you should be seeing errors in the error console and possibly at compile time
16:30	hiredman	zipper: if you do quote the list, you local 'regex' in the let is being bound the result of the if, which is a list containing a regex, not a regex
16:31	hiredman	oh, I guess you only care about the second
16:31	andyf	amalloy: Sorry, meant to send one of my recent comments to you. Senior moment.
16:32	hiredman	zipper: what does "fails" mean? a compilation error, a runtime error, or it fails to match what you want?
16:32	zipper	hiredman: Yes I am seeing an error in the JS console
16:32	hiredman	for which snippet?
16:33	zipper	hiredman `Uncaught TypeError: /\/[\-\[\]\\/\{\}\*\+\?\.\\\^\$\\|]\/gi/.call is not a function`
16:33	zipper	hiredman: I assume it comes from L2
16:34	zipper	I can see that because it tries to call that regex.call
16:34	zipper	plus it ends with /gi
16:34	hiredman	zipper: right, so A. you don't need to quite the regexes B. don't call them as zero argument functions
16:34	hiredman	to quote
16:35	zipper	hiredman: How do I avoid calling it if not using '
16:35	zipper	?
16:35	hiredman	you have the ' and are still calling
16:35	hiredman	(foo) is a function call
16:35	hiredman	you have (some-regex)
16:35	hiredman	that is trying to invoke the regex as a 0 argument function
16:36	hiredman	you use of ' does nothing in this case, because regexes are literals that evaluate to themselves
16:37	zipper	Okay so I get rid of the () and have that read as; `#"/[\-\[\]\/\{\}\*\+\?\.\\\^\$\\|]/gi"`
16:37	hiredman	'(foo) would mean it is a quoted list, not a function call, but then you would have a list containing a regex, not a regex
16:37	gfredericks	andyf: is going to conferences more difficult when your kids are in college?
16:37	zipper	That's a regex now
16:37	hiredman	zipper: yes, that is
16:38	zipper	hiredman: Trying it out
16:38	zipper	My chest hurts, it's so cold :(
16:38	{blake}	component-did-update does the trick.
16:39	andyf	gfredericks: Only in that I feel budget tightness more than before then. I should splurge on a Conj before they are done, though.
16:40	gfredericks	andyf: are you telling me college is going to cost money??
16:40	hiredman	if there was money in the future, instead of just hugs
16:41	andyf	gfredericks: I fully believe that it will become common-place for some cheaper alternative to traditional 4-year degree to be acceptable for more jobs than they are now. Not sure when that will happen. Maybe a decade or 2 from now?
16:42	Somelauw	How to quickly run a clojure.clj file interactively which is not part of a project?
16:43	Somelauw	Is lein repl, (source filename) the only way?
16:43	gfredericks	andyf: I need a proposal on my desk by 14 years from now
16:43	hiredman	http://clojure.org/reference/repl_and_main
16:43	hiredman	Somelauw: source doesn't run anything
16:48	amalloy	you know, i read "that's a regex now" as "that's a regret now", and it seemed even more apt, given that the subject is #"/[\-\[\]\/\{\}\*\+\?\.\\\^\$\\|]/gi"
16:48	gfredericks	a programmer has a regret, and thinks, "I know, I'll use a regular expression!" ...
16:48	hiredman	amalloy: also, it is being used to edit a string, that is then being turned into a regex
16:49	hiredman	crazy
16:49	Somelauw	Running 'java -cp clojure.jar clojure.main' says 'Error: Could not find or load main class clojure.main' I just want to run a single script without turning this script into a project.
16:50	hiredman	Somelauw: because you picked a random jar instead of the jar that contains clojure
16:50	hiredman	clojure.jar doesn't, in this context, mean some jar with your clojure code in it, it means the jar containing the clojure runtime
16:52	Somelauw	so clojure.jar should be the full path to the clojure.jar that lays somewhere deep in ~/.m2
16:53	hiredman	or whereever, you can download the jar from the website
16:53	hiredman	http://clojure.org/community/downloads
16:54	Somelauw	so that is ~/.m2/repository/org/clojure/clojure/1.8.0/clojure-1.8.0.jar
16:56	Somelauw	I'll just write a wrapper for it
16:57	Somelauw	I only miss autocompletion in my repl that lein has
16:58	ridcully	don't forget to put rlwrap -m -M .clj -C clojure around it :)
17:01	Somelauw	ridcully: ehm, do I replace clojure by 'java -cp clojure.jar clojure.main'?
17:04	ridcully	Somelauw: no. it's just a name used for the history file
17:04	ridcully	Somelauw: this will use ~/.clojure_history then
17:05	andyf	gfredericks: My iPhone calendar actually lets me schedule events 14 years in advance. Huh. Not sure whether the event I just created will get copied to whatever device I am using to remind me of calendar events then.
17:06	Somelauw	ridcully: I'm not sure at what place of your command to insert the whole 'java -cp clojure.jar clojure.main'
17:09	ridcully	Somelauw: i use it like this (some var with the version involved): rlwrap -m -M .clj -C clojure java -cp ~/.m2/repository/org/clojure/clojure/1.8.0/clojure-1.8.0.jar clojure.main
17:10	ridcully	Somelauw: the -m gives you multine capabilities - so you can open your $EDITOR with ctrl-^. the -M tells it to put a .clj on that "file" to open so your $EDITOR behaves nicely
17:27	Somelauw	ridcully: thanks, that works well, although it would be preferable to still use lein somehow
17:30	ridcully	Somelauw: you can always run a `lein repl` from anywhere
17:30	spuz	Is there a function that combines filter and first? I.e. it returns the first element of a sequence that matches a predicate?
17:30	ridcully	Somelauw: add the `try` plugin for it and you can also fetch some deps right into it
17:31	Somelauw	ridcully: I know I can run lein repl from anywhere, just not how to run it with a script that is not part of a project.
17:31	amalloy	spuz: incredibly, there is not
17:33	Somelauw	lein repl filename doesn't work for me
17:33	andyf	spuz: Some Clojure 'utility libraries' include such a thing, e.g. find-first in Medlay: https://github.com/weavejester/medley/blob/master/src/medley/core.cljc
17:33	Somelauw	then it says unknown subcommand
17:33	andyf	spuz: er, Medley, even.
17:34	spuz	andyf, thanks
17:35	Somelauw	but filter is lazy, so first-filter should already be fast
17:49	justin_smith	ridcully: cool rlwrap tricks
17:56	lerax	Someone knows a good lib for pt-br natural lang processing?
18:03	ridcully	Somelauw: mhm i might have put you on the wrong track then. i only saw your "have to wrap it" bits and tought you just want to have a faster repl
18:15	ImBadAtClojure	Is there a way to convert a clojure vector of java objects into a java List<java object's type>?
18:15	hiredman	that is a generic, those don't actually exist
18:16	ImBadAtClojure	So it's impossible?
18:16	hiredman	no, you don't need to
18:16	rhg135	generics are only a delusion that javac enforces
18:17	hiredman	javas generic types exist in the java (the language) compiler, once you have bytecode running on the jvm, they don't exist (this is called erasure and I am sure there are like a billion blog posts about it)
18:17	hiredman	you just need something that implements List
18:17	ImBadAtClojure	so when I send this custom data structure back to java how do I get it into java datastructures?
18:17	hiredman	if you pull up the java docs for List, there are links to few handy implemntations of that interface
18:18	hiredman	,(java.util.ArrayList. (vec (range 10)))
18:18	ImBadAtClojure	I was just trying to map it directly into POJOs somehow
18:18	clojurebot	[0 1 2 3 4 ...]
18:18	hiredman	,(type (java.util.ArrayList. (vec (range 10))))
18:18	clojurebot	java.util.ArrayList
18:18	hiredman	clojure data structures are java data structures
18:19	hiredman	so depending on what interfaces java requires and what methods it calls, you can just pass in clojure data structures
18:19	ImBadAtClojure	Fair enough, so just pass it back in a simple array list then map into my pojos on the java side?
18:19	hiredman	ImBadAtClojure: I am not sure what you mean?
18:19	hiredman	any java objects you want to construct, you can construct from clojure and pass to java
18:21	ImBadAtClojure	But to construct one of my java objects in clojure I need to create a list of a previously constructed java object
18:21	ImBadAtClojure	ClassCastException java.util.ArrayList cannot be cast to [L<myType>;
18:21	TEttinger	oh
18:21	TEttinger	that isn't a list
18:21	TEttinger	that looks like an array
18:22	TEttinger	,(class (make-array java.util.String 2))
18:22	clojurebot	#error {\n :cause "java.util.String"\n :via\n [{:type clojure.lang.Compiler$CompilerException\n :message "java.lang.ClassNotFoundException: java.util.String, compiling:(NO_SOURCE_PATH:0:0)"\n :at [clojure.lang.Compiler analyze "Compiler.java" 6688]}\n {:type java.lang.ClassNotFoundException\n :message "java.util.String"\n :at [java.net.URLClassLoader$1 run "URLClassLoader.java" 366]}]\n :...
18:22	TEttinger	,(class (make-array java.lang.String 2))
18:22	clojurebot	[Ljava.lang.String;
18:22	ImBadAtClojure	that would make an array of strings right?
18:22	ImBadAtClojure	so I can make an array of my java object's type in the same way?
18:23	TEttinger	yeah, it looks like your exception is caused by passing an ArrayList where it actually wants an array
18:23	ImBadAtClojure	Yeah I was just trying random things since I didn't know how to create a new array with a non primative type
18:24	ImBadAtClojure	I'll try it, thanks :D
18:24	TEttinger	arrays are kinda less supported in clojure than other data structures since they can't be made to have the nice features in clojure's immutable data structures
18:24	TEttinger	arrays are always mutable, fixed-size
18:24	hiredman	that is non-sense
18:25	amalloy	i like the implication that clojure's built-in structures are immutable but change size all the time
18:25	TEttinger	heh
18:25	TEttinger	good point
18:26	TEttinger	I do have the feeling that arrays are not quite first-class in clojure, at least partly because of the separate amap, areduce, etc. fns for them
18:27	hiredman	TEttinger: infact, map and reduce both work on arrays just fine
18:27	hiredman	TEttinger: amap and areduce are extra support for working on arrays
18:27	TEttinger	I didn't know that, I guess seq works on arrays
18:27	ImBadAtClojure	so can I do (make-array <custom java type class> ..)?
18:27	TEttinger	yeah, then the dimension or dimensions
18:27	TEttinger	,(doc make-array)
18:27	clojurebot	"([type len] [type dim & more-dims]); Creates and returns an array of instances of the specified class of the specified dimension(s). Note that a class object is required. Class objects can be obtained by using their imported or fully-qualified name. Class objects for the primitive types can be obtained using, e.g., Integer/TYPE."
18:28	hiredman	ImBadAtClojure: you can, I would recomend looking at the set of clojure functions with 'array' in the name
18:28	amalloy	you'd almost certainly prefer to call into-array
18:28	ImBadAtClojure	awesome, thanks guys
18:28	TEttinger	right
18:28	hiredman	,(doc apropos)
18:28	clojurebot	"([str-or-pattern]); Given a regular expression or stringable thing, return a seq of all public definitions in all currently-loaded namespaces that match the str-or-pattern."
18:28	amalloy	although hiredman's advice is probably better
18:28	rhg135	what is the best way to shutdown an agent?
18:29	rhg135	just stop banging on it?
18:31	hiredman	I have some projects where object arrays were used more less like a C struct, in clojure, works fine. kind of a pain, if I did it regularlly I would have a nice set of macros that generate setter and getter functions
18:58	TEttinger	yeah, actually I might need some advice on how to best interop with array-heavy java code. I still need to get some stuff (I think it's setup related) fixed in my installation of cursive, deps still aren't visible in the editor but they are in lein repl
18:59	TEttinger	but once I can pull in the java deps, I need to wrap them
18:59	TEttinger	I don't know if it's an appropriate case for an issue on cursive somewhere
19:13	rhg135	try telling that to oracle
21:51	sineer	I'm inside a (go (loop (try .... (catch Exception e e)))) and I try/catch the block that run this go block yet my exception isn't caught by that try/catch block? Clojure 1.8..
21:52	justin_smith	sineer: I assume you mean (go (loop [] (try ...)))
21:52	justin_smith	sineer: is the thing thrown a subclass of Exception?
21:53	sineer	justin_smith: yeah, it was throwing allright, let me push code on github it'll make our life easier
21:53	justin_smith	sineer: what I am asking is what the class thrown was
21:53	justin_smith	is it an Exception or maybe an Error or some other class that catching Exception would not match
21:54	sineer	NullPtrException
21:54	justin_smith	yeah, share a paste / github
21:56	sineer	https://github.com/sineer/sort-challenge
21:56	sineer	line 46 of boot.clj will throw NullPtrException
21:57	sineer	I believe it catch it and keep running the go blocks until cnt is 0 but the try/catch in -main never catch anything
21:58	justin_smith	well, of course, if the try/catch in init-products-from-chan! catches the error, why would -main ever see it?
21:59	justin_smith	sineer: also you don't need a new let block at line 51, those bindings can be part of the let block right before
21:59	justin_smith	,(let [a 0 b (inc a) c (inc b)] c)
21:59	clojurebot	2
22:00	sineer	I need to run the (if family (assoc info :family family)) before I do the other (let ..
22:00	justin_smith	why?
22:00	clojurebot	http://clojure.org/rationale
22:00	justin_smith	why would that matter at all?
22:00	sineer	I suppose I can do it after..
22:01	justin_smith	sineer: (if family (assoc family x y)) does not have any side effects
22:01	justin_smith	you need to bind the return value, or it is a noop
22:01	justin_smith	family is immutable, assoc does not change it
22:01	justin_smith	the correct version of that line is to have, inside your let binding block 'family (if family (assoc family ...))
22:01	justin_smith	it needs to be a binding or it might as well not exist
22:02	justin_smith	so you only need one let block
22:02	justin_smith	that binding is just the next binding in the block
22:02	justin_smith	compare:
22:02	justin_smith	,(let [a {}] (assoc a :b 1) a)
22:02	clojurebot	{}
22:03	justin_smith	,(let [a {} a (assoc a :b 1)] a)
22:03	clojurebot	{:b 1}
22:03	justin_smith	sineer: do you see the difference?
22:03	sineer	I'm just confused now :(
22:04	justin_smith	sineer: assoc does not mutate its arg, it creates a brand new data structure
22:04	sineer	oh shit yeah I get it now :(
22:04	justin_smith	sineer: you don't need two let blocks
22:04	sineer	sorry
22:04	justin_smith	sineer: don't be sad, I'm trying to help
22:04	justin_smith	I'm not trying to be mean
22:04	sineer	I know, I'm sad because I feel stupid having such a hard time with this
22:05	justin_smith	everything is hard if you haven't learned it yet
22:05	sineer	yeah but it shouldn't be that hard else I'm either stupid or it's too damn hard I havne't fully decided which one it is yet
22:06	TimMc	justin_smith: throw in some commas
22:07	justin_smith	TimMc: in the let blocks?
22:07	TimMc	yeah
22:07	justin_smith	ahh, yeah
22:07	sineer	I just realized the version I pushed print the exception on line 59, I use to just return it that's why I expected -main to catch it..
22:07	justin_smith	,(let [a {}] (assoc a :b 1) a)
22:07	clojurebot	{}
22:07	justin_smith	,(let [a {}, a (assoc a :b 1)] a)
22:07	clojurebot	{:b 1}
22:07	justin_smith	sineer: returning an exception is not the same as throwing it
22:08	justin_smith	it might look the same with some printing rules, but it's different
22:08	sineer	ok so I need to rethrow inside go block for -main to catch it?
22:08	justin_smith	yes
22:09	justin_smith	otherwise you just return an exception, which is a value like any other
22:09	justin_smith	sineer: in fact you never even consume the channel returned from that go block
22:09	sineer	no I just assign it so that main don't exit right away
22:10	justin_smith	right, just saying by returning it from the go block, it might get read if someone consumed the chan
22:10	justin_smith	but nobody even does that
22:11	sineer	now I tried replacing that print on line 56 by throw and I see the exception trace but then my program just hang, it doesn't look like -main is caching the exception
22:11	sineer	line 59 I mean
22:11	justin_smith	go can be kind of weird about exceptions, it's best to catch them before you exit the scope of a go block and handle them best you can
22:12	justin_smith	basically what happens is your code is running in one of the threads of the go thread pool, and your exception bubbles up to that thread, not to the -main that launched the go block, so you are at the mercy of the default go block error handler, which is pretty much useless
22:13	justin_smith	since it's in a different thread, the exception can't go back up to -main
22:13	sineer	I thought I read somewhere it did so since clojure 1.6?
22:13	sineer	I probably missinterpreted something
22:13	justin_smith	probably - how would an exception in one thread interrupt another thread?
22:14	sineer	yeah that doesn't make sense but I thought there was some magic I didn't know about...
23:02	solatis	what do people recommend for mocking stuff in tests?
23:02	solatis	specifically, things like message queues
23:03	solatis	i am in doubt whether to make my tests just /depend/ upon the availability of those, and create ad-hoc queues
23:03	solatis	but on the other hand, i could just as well mock the interface to the queue
23:04	sineer	re
23:04	hiredman	solatis: are you using clojure.test?
23:04	solatis	yep
23:05	hiredman	clojure.test has once (per namespace) and each (per deftest) fixtures
23:05	solatis	yes
23:05	solatis	so i'm already doing that for my database
23:05	solatis	but now i'm depending upon a lot more things (specifically, Amazon AWS services)
23:05	solatis	and wonder what the best strategy for this is
23:06	solatis	either using the actual service (albeit self-contained), or mocking the interface
23:06	sineer	er sorry. I have a question about how to build a regex.. I want to (let [regex #"foo[-][_]"]) something like that. but using a var instead of "foo". Basically I need a regex that will match myvar with optional - or _ at the end
23:06	hiredman	it can get kind of complicated
23:06	solatis	yes i know, i don't think there is a "magic bullet" for this and it depends on a case-by-case scenario
23:06	hiredman	you can make all your interfaces to aws services pluggable and use some local plugin when testing
23:07	solatis	i was thinking about this: https://clojuredocs.org/clojure.core/with-redefs-fn
23:07	solatis	and put that in a fixture
23:07	solatis	or something
23:09	hiredman	you can do that, but in my experience you end up with a sprawl of things you need to redef, and it is hard to track what a test is actually doing
23:09	solatis	right
23:09	solatis	so the answer is, pluggable service
23:10	solatis	but then that doesn't test the actual integration with the message queue
23:10	solatis	argh
23:10	hiredman	at my previous job we ended up with a macro we called with-var-roots which was written before with-redefs was added to clojure, and when we had the opportunity to green field another project we tried to avoid that again
23:11	solatis	i can assume so
23:12	solatis	ok, then i think what i want to do
23:12	solatis	*i think i know what i want to do
23:12	solatis	just use the damned message queue
23:12	solatis	unless it's really impractical not to do so
23:12	hiredman	mocking is really painful, but sometimes you have to, because you can't test against the actual service for whatever reason
23:13	solatis	yes that is true, however when you use something like amazon AWS, you have a complete API to create nearly all services ad-hoc and on-demand
23:13	solatis	so that's just what i'm going to do
23:15	solatis	ok, so, semi-related question
23:15	clojurebot	I don't understand.
23:15	solatis	https://clojuredocs.org/clojure.test/deftest
23:16	solatis	i am using tests, with fixture
23:16	solatis	the fixture generates something i want to pass around to all tests
23:16	solatis	in this case, a random id for a message queue
23:16	solatis	how can i pass this argument to all the tests?
23:17	solatis	the test function passed to the fixture appears to be a function that does not accept arguments
23:18	sineer	how do I create a regular expression and assign it to a var by concatenating strings? something like #(str var "[-_]") but that's not what I expected..
23:19	hiredman	,(doc re-pattern)
23:19	clojurebot	"([s]); Returns an instance of java.util.regex.Pattern, for use, e.g. in re-matcher."
23:20	sineer	thanks!
23:29	sineer	any clue how to build a regex with a wildcard - or _ anywhere within a string? I need to match "string" "s-tring" "st-ring" ...
23:48	solatis	ohhhh i understand what i need to do with fixtures now to pass around arguments!
23:48	solatis	and the solution is _not_ pretty