#clojure – 2015-06-17

2015-06-17

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00:35	tmtwd	oops
00:35	tmtwd	is that any sensitive information?
00:36	TEttinger	tmtwd, I don't see anything bad
00:37	TEttinger	so, https://scontent-sjc2-1.xx.fbcdn.net/hphotos-xfa1/v/t1.0-9/11390060_3127051372334_2540245238860767788_n.jpg?oh=5f45dea77976c3b70b8b3a62b7872fb7&oe=5624C30F
00:37	tmtwd	heh
00:39	TEttinger	nice story behind that cat, she is a feral who was trapped to be spayed, but she had to give birth to her kittens first. she was extremely defensive of the little ones (that explains the photo), but now she's spayed and back where she wants to be in the forest, and her babies are getting adopted soon
00:40	TEttinger	but it's really a "blood is thicker than water, and if you touch my family there WILL be blood" type of cat face
00:56	Surgo	bit of a strange question...I know it's really hackish, but is there any particular reason it would be bad to add entries to default-data-readers? I can't see any other way to transparently effect both clojure.core/read{,-string} and clojure.edn/read{,-string}
04:08	benhuda	helo
04:09	benhuda	im migrating code from windows to the JVM (clojure and java), and wondering -- is there a good way to run processes like windows services in java?
04:09	benhuda	aside from the obvious main while(true) loop... CLI daemons that have a lifecycle and can be managed and introspected
04:10	benhuda	maybe i should take a look at how Storm and Cassandra run
04:10	p_l	benhuda: two different things - wrappers that run Java applications as services (Jsvc?) and for hosting multiple applications/services in one process, a Java application server, afaik there's a clojure-oriented package based on JBoss
04:11	benhuda	well it will be a service that runs and never quits... its a poller service. every X minutes it will perform DB queries forever
04:11	benhuda	so it has no Web / such concerns, just database
04:11	p_l	benhuda: for something simple, Jsvc or similar will be enough
04:12	benhuda	i'm aware i can just do an endless loop, but i'm looking for something more infrastructural to enjoty
04:19	zot	i'm editing a bunch of files in emacs, and usually re-eval after mkaing changes, but sometimes forget. is there a simple way to eval all open clj files, so that my cider/repl is up-to-date with my source?
04:26	scottj	zot: maybe M-x cider-refresh
04:26	scottj	bound to C-c C-x
04:27	zot	scottj: clever, if i read that code right if will reset, and force all deps to get reloaded along the way :)
04:28	zot	(inc scottj)
04:28	lazybot	⇒ 4
07:32	justin_smith	zot: there is also tools.namespace.repl/refresh
07:33	justin_smith	which will reload code, but only from your current project, and will also delete vars that no longer exist
07:33	zot	justin_smith: thanks. i knew about namespace, but curiously hadn't seen how to just execute arbitrary code in the repl until seeing the cider-refresh code (which calls namespace/refresh first). so cider-refresh solved 2 problems for me at the same time :)
08:26	Chaze	Hi. I want to implement a relatively generic function "parallel", which is basically the same as the Haskell arrow (&&&) - in case you're familiar with this. I got this, but its ugly: https://www.refheap.com/f8071392381918fae31dbf568
08:28	Chaze	more simple, why doesn't the following work? let functions be a list of unary functions and arguments a list of arguments for them, I want to do (map apply functions arguments)
08:29	justin_smith	Chaze: apply requires its last arg to be in a list
08:29	justin_smith	or, more precisely, in a collection
08:30	Chaze	ah, so (map apply functions (map list arguments)) may work?
08:30	justin_smith	,(map apply [inc dec + -] [[1] [43] [8 17] [1000 33]])
08:30	clojurebot	(2 42 25 967)
08:30	justin_smith	Chaze: if arguments is a list of single items for unary functions, yes
08:31	Chaze	perfect, thank you
08:42	justin_smith	Chaze: another option would have been (map #(%1 %2) functions arguments) because map is varargs
08:43	Chaze	justin_smith: strange, that there is no predefined function #(%1 %2)
08:44	jonathanj	i can't recur with a different arity to the function i'm recurring from?
08:44	justin_smith	jonathanj: that's true, you cannot
08:44	jonathanj	okay
08:46	justin_smith	jonathanj: though you could do something similar to recurring on different arities with trampoline
08:46	justin_smith	trampoline can be weird to use at first though
08:52	justin_smith	,(trampoline (fn bounce ([] #(bounce 1)) ([x] #(bounce 2 x)) ([x y] #(bounce x 3 y)) ([x y z] [z y x]))
08:52	clojurebot	#<RuntimeException java.lang.RuntimeException: EOF while reading>
08:52	justin_smith	oops
08:52	justin_smith	,(trampoline (fn bounce ([] #(bounce 1)) ([x] #(bounce 2 x)) ([x y] #(bounce x 3 y)) ([x y z] [z y x])))
08:53	clojurebot	[1 3 2]
08:53	jonathanj	justin_smith: i think just kickstarting the recur with a lower arity version is probably good enough for what i want
08:53	justin_smith	OK
08:53	jonathanj	thanks
08:56	justin_smith	letfn / trampoline is a nice combo sometimes
09:06	kaiyin	It seems learning clojure web development is very difficult because everything is changing so fast. Books published only a few months ago are already outdated.
09:08	dagda1_	how can I use macroexpand to tell me how the thread-last macro will expand out, I've tried this (macroexpand (->> (iterate scratch.core/cuts [1 2 3 4]) (map count) (take-while pos?)))
09:08	dagda1_	but it gives me the result
09:08	lumafi	you need to quote the macro expression
09:09	justin_smith	,(macroexpand '(->> (iterate scratch.core/cuts [1 2 3 4]) (map count) (take-while pos?)))
09:09	clojurebot	(take-while pos? (map count (iterate scratch.core/cuts [1 2 3 4])))
09:09	dagda1_	lumafi: thanks
09:17	phillord	If I want to install lein on windows, are there any standard locations that I can drop it, that don't require the use to fiddle with their path settings?
09:17	phillord	the windows installer looks nice, but installs 1.7
09:18	phillord	or am I wrong about this?
09:28	expez	anyone have time to take a look at https://github.com/expez/str before I announce? Any glaring omissions? I'm also not sure about aliasing clojure.string like this, but I find the alternatives unattractive :/
09:28	TEttinger	phillord, it shouldn't install an old version?
09:28	TEttinger	which link are you using, phillord?
09:29	TEttinger	expez, uh
09:29	TEttinger	,str
09:29	clojurebot	#object[clojure.core$str 0x40de81f5 "clojure.core$str@40de81f5"]
09:29	TEttinger	that seems like a very strange choice for a library name
09:31	expez	TEttinger: well, it is a string manipulation library. Not sure a random girls name or literary character would be much better :p
09:31	TEttinger	https://github.com/expez/str/blob/master/src/str/core.clj#L107
09:31	TEttinger	typo there, not sure what needles are in the later fns
09:32	TEttinger	expez, true but it's confusing, "which str do you mean again?"
09:32	dagda1_	I think I am failing to see why the thread last macro is not called the thread first macro
09:33	TEttinger	dagda1_: thread last is ->> , and inserts the arg you give it as the last argument to each of the following forms
09:33	oddcully	dagda1_: last as in last argument. not from right to left
09:33	expez	TEttinger: needles are the thing we look for in the haystack (string). You're the second person to wonder about this. I stole it from s.el because I thought it was clever.
09:33	TEttinger	,(->> [1 2 3] (map inc) (reduce +))
09:33	clojurebot	9
09:36	TEttinger	expez, as for library names, there's possibly: textual , stringy , superstring (after the physics theory), wordsmith
09:37	TEttinger	I don't think str specifically is trouble here because it's always really str.core, it still seems confusing to me
09:37	dagda1_	TEttinger: so that expands to (reduce + (map inc [1 2 3])) where does the last come in because it calls reduce first?
09:38	TEttinger	dagda1_, not what it expands to
09:38	expez	TEttinger: https://github.com/expez/str/blob/master/src/str/core.clj#L34 what do you think of this?
09:38	TEttinger	the last argument passed to reduce is the threaded form
09:38	TEttinger	contrast with:
09:40	TEttinger	,(-> [1 2 3] (concat [4]) (conj 5))
09:40	clojurebot	(5 1 2 3 4)
09:40	TEttinger	which is because concat returns a seq, and seqs append to beginning
09:41	TEttinger	which is the same as
09:41	TEttinger	,(conj (concat [1 2 3] [4]) 5)
09:41	clojurebot	(5 1 2 3 4)
09:42	TEttinger	you can see that in the thread-first case, the [1 2 3] becomes the first arg to concat
09:42	TEttinger	in the thread-last case, it become the last arg to map and reduce
09:43	dagda1_	TEttinger: brilliant, thanks
09:43	TEttinger	expez, it doesn't strike me as a bad idea, especially since you aren't drawing in extra deps or anything
09:44	TEttinger	it seems a bit... I dunno, if you're using it in your code it's probably fine, if it's only for end users they could really just include clojure.string themselves
09:44	expez	TEttinger: I'd like to avoid having both clojure.string :as str superstring.core :as ss in the same namespace heh
09:45	TEttinger	ah ok, fair enough
09:45	expez	TEttinger: I also didn't want to re-implement clojure.string because that's a waste of time and if I change the semantics people will get tripped up
09:46	expez	so aliasing seems like a good alternative
09:46	TEttinger	yeah, good points
09:46	expez	I think I like superstring because it's actually extending clojure.string :p
09:47	dagda1_	the penny has dropped :)
10:35	phillord	TEttinger: sorry, I realise that I was wrong -- the installer SAYS it is going to install Leiningen Version 1.0, but actually doesn't
10:37	phillord	Now, why does bitbucket not have a issue tracker!
10:38	TEttinger	hm, it should
10:38	pbx	phillord, it does
10:38	littleli	yeah, it does
10:38	pbx	can be enabled/disabled by the project owner though
10:39	oddcully	they even sell one ^_^
10:40	phillord	for the lein installer, I can't see one
10:40	phillord	PR yes, issues no
10:40	pbx	then they haven't enabled it.
10:40	TEttinger	it might use a different site to track issues
10:48	crocket	Does clojure have a decent reactive GUI library?
10:52	sm0ke	no
10:52	sm0ke	but there are some which are written in clojure/script
10:53	sm0ke	nothing inbuilt in clojure afaik
10:53	wasamasa	someone wrapped swing
10:53	wasamasa	https://github.com/daveray/seesaw
10:53	TEttinger	I believe quil may have reactive parts
10:53	sm0ke	for web side you have reagent om
10:54	TEttinger	the problem on desktop is that you mostly have to use java libs or wrappers around them to display fancy graphics with any performance, and most java libs are not written for reactive style, I think
10:54	sm0ke	hmm
10:54	sm0ke	actually facebook recently announced react native
10:55	crocket	GUI seems to be a mine field.
10:55	sm0ke	i am wondering if coljurescript -> js -> native
10:55	sm0ke	can be done
10:55	TEttinger	however, there's stuff like chromium embedded if you want to use cljs on desktop
10:55	TEttinger	$google chromium embdedded framework
10:55	lazybot	[chromiumembedded / cef — Bitbucket] https://bitbucket.org/chromiumembedded/cef
10:55	sm0ke	wow didnt know about that
10:55	sm0ke	must be awfully heavy though?
10:56	wasamasa	crocket: no shit
10:56	TEttinger	github for windows uses it, so does spotify, uplay, desura, steam client, recent AIM...
10:56	wasamasa	crocket: next thing you proclaim is that any real-world programming is
10:57	crocket	Is there a viable path toward applying reactive programming on native GUI programs?
10:57	crocket	chromium embedded?
10:57	sm0ke	https://github.com/atom/electron
10:57	crocket	There is JavaFX...
10:58	crocket	Would it be reasonable to write a reactive wrapper around JavaFX in clojure?
10:58	sm0ke	http://react-native.org/
10:58	TEttinger	atom looks nice
10:59	crocket	react-native, atom, blah blah, ..., chromium embedded
10:59	sm0ke	i guess react native would be perfect for you crocket
10:59	sm0ke	its reactive and native heh
10:59	crocket	sm0ke, After I try, I may change my mind.
10:59	crocket	It involves HTML and CSS.
11:00	sm0ke	you want to write in C?
11:00	crocket	ha
11:00	crocket	sm0ke, Some people are trying to write JavaFX bindings in clojure and frege.
11:00	sm0ke	is javafx reactive?
11:01	crocket	I don't know.
11:01	sm0ke	i thought you said reactive?
11:01	crocket	https://github.com/TomasMikula/ReactFX
11:02	crocket	I didn't say JavaFX was known to be reactive.
11:03	sm0ke	crocket: you want to write over jvm?
11:04	crocket	sm0ke, I don't know...
11:04	crocket	But, it's useful to know
11:04	sm0ke	:/
11:04	crocket	It's useful to know that clojure has decent GUI libraries on JVM.
11:05	crocket	There is https://github.com/aaronc/fx-clj
11:05	crocket	https://github.com/aaronc/fx-clj supports reactive programming over JavaFX.
11:05	crocket	Since JavaFX is compatible with Java 8 lambdas, it has a lot of callbacks.
11:10	voidnoid	is datomic OT in here?
11:11	crocket	It seems reactive native is for Mac OS.
11:11	crocket	React Native "Build native iOS and Android apps with JavaScript."
11:25	crocket	hmm
11:26	csd_	How might I check whether a vector is a subclass of java.util.Collection?
11:26	csd_	instance? doesn't seem like the right function
11:26	justin_smith	,(isa? java.util.Collection [])
11:26	clojurebot	false
11:26	justin_smith	(doc isa?)
11:26	clojurebot	"([child parent] [h child parent]); Returns true if (= child parent), or child is directly or indirectly derived from parent, either via a Java type inheritance relationship or a relationship established via derive. h must be a hierarchy obtained from make-hierarchy, if not supplied defaults to the global hierarchy"
11:26	justin_smith	oh
11:27	justin_smith	,(isa? [] java.util.Collection)
11:27	clojurebot	false
11:27	csd_	that can't be correct
11:27	csd_	is it?
11:27	justin_smith	yeah, I am doing it wrong
11:28	csd_	,(isa? () java.util.Collection)
11:28	clojurebot	false
11:29	csd_	,(isa? clojure.lang.PersistentVector java.util.Collection)
11:29	clojurebot	true
11:29	justin_smith	oh, it needs the type
11:29	justin_smith	makes sense
11:29	Bronsa	,(instance? [] java.util.Collection)
11:29	clojurebot	#error {\n :cause "clojure.lang.PersistentVector cannot be cast to java.lang.Class"\n :via\n [{:type java.lang.ClassCastException\n :message "clojure.lang.PersistentVector cannot be cast to java.lang.Class"\n :at [clojure.core$instance_QMARK___4128 invoke "core.clj" 142]}]\n :trace\n [[clojure.core$instance_QMARK___4128 invoke "core.clj" 142]\n [sandbox$eval143 invoke "NO_SOURCE_FILE" 0]\n [...
11:30	Bronsa	,(instance? java.util.Collection [])
11:30	clojurebot	true
11:30	Bronsa	(╯°□°）╯︵ ┻━┻
11:30	csd_	ah
11:30	justin_smith	(inc Bronsa)
11:30	lazybot	⇒ 113
11:30	csd_	justin_smith: you use Cursive predominantly right?
11:30	justin_smith	Bronsa: that's what I was looking for, found it just after you shared that
11:30	justin_smith	csd_: no, I do not
11:30	justin_smith	I'm a fan, but I can't do IDEs
11:31	csd_	It feels really clunky to me but maybe that's just lack of experience with it. I think though that if I were working really closely with a Java project that it'd be essential
11:31	csd_	thoughts?
11:32	justin_smith	yeah, IDEs in general don't tend to work the way I want to work I think. I gave up on cider even.
11:32	csd_	what do you use now
11:32	justin_smith	a repl in a terminal
11:33	csd_	what if you need to traceback to the clojure Java code for example
11:33	justin_smith	stack traces / reflection + google
11:34	justin_smith	I'm basically a cave man
11:34	csd_	whatever works
12:14	crocket	What are good ways to write reactive GUI apps in clojure?
12:15	snowell	Reagent works well for me
12:15	snowell	http://reagent-project.github.io/
12:15	crocket	I think I heard a better alternative to react on clojure.
12:16	justin_smith	the two main ones are om and reagent
12:16	snowell	Om or re-frame are the only other ones I've heard of
12:17	oddcully	there is also rum, but thats not what you asked
12:17	blkcat	om looks very interesting
12:17	justin_smith	re-frame is a toolkit for reagent
12:18	CookedGryphon	Hey, found a weirdness with update, think I know what's happening, but if anyone could offer comment...
12:19	CookedGryphon	,(update [] 0 (fnil inc 0))
12:19	clojurebot	[1]
12:19	CookedGryphon	,(update [] 1 (fnil inc 0))
12:19	clojurebot	#error {\n :cause nil\n :via\n [{:type java.lang.IndexOutOfBoundsException\n :message nil\n :at [clojure.lang.PersistentVector assocN "PersistentVector.java" 183]}]\n :trace\n [[clojure.lang.PersistentVector assocN "PersistentVector.java" 183]\n [clojure.lang.PersistentVector assocN "PersistentVector.java" 21]\n [clojure.lang.APersistentVector assoc "APersistentVector.java" 333]\n [clojure....
12:19	csd_	what would be the best way to generalize a function so that if i call it in my production code it does X and if i call it in my test code it does Y?
12:19	justin_smith	,(update [0] 1 (fnil inc 0))
12:19	clojurebot	[0 1]
12:20	justin_smith	CookedGryphon: I think it just doesn't know how to skip indexes, but it is happy to make the incremental next one
12:20	CookedGryphon	yeah
12:20	CookedGryphon	I just found it surprising
12:20	CookedGryphon	expected it to either blow up in both cases or simply return the input unchanged if it can't set the key
12:21	justin_smith	clojure is often surprising, while still being simple
12:22	snowell	csd_: If you're using leiningen, you can set up profiles. And you can pair that with something like environ to pull different environment variables
12:23	csd_	snowell: can you elaborate? im not sure how that would work
12:23	csd_	would i in my environ file declare the code?
12:23	snowell	csd_: https://github.com/technomancy/leiningen/blob/master/doc/PROFILES.md
12:24	justin_smith	csd_: I've used environ to set a key I can check, then switched implementation at runtime based on the key
12:24	snowell	And what justin_smith just said is what I was going to type next :)
12:24	csd_	justin_smith: but then i have a `cond` in my production code that says, if you're in a test environment, do this, right?
12:25	justin_smith	csd_: or a multimethod (defmulti run-server (fn [& args] (env :server-version)) (defmethod run-server "prod" ...) (defmethod run-server "dev" ...)
12:26	justin_smith	since defmethod can dispatch on an arbitrary function, it can ignore all the args and just use environ
12:26	csd_	oh thats cool
12:27	csd_	justin_smith: would you pick that over with-bindings?
12:27	crocket	Does react provide a decent variant of functional reactive programming?
12:27	justin_smith	csd_: with-bindings is for thread local stuff isn't it?
12:28	csd_	justin_smith: not sure
12:28	crocket	My gut feeling tells me that react doesn't promote FRP much.
12:28	justin_smith	crocket: there is no actual FRP for clojure as far as I know.
12:29	csd_	justin_smith: f its just for testing i don't see what it matters if its thread local
12:29	justin_smith	csd_: oh, I thought this was more general, like dev vs. staging vs. prod, sorr
12:30	csd_	yeah although i dont want it more coupled than it needs to be
12:30	justin_smith	crocket: I take that back, I forgot about zelkova https://github.com/jamesmacaulay/zelkova one of the talks I missed from clojure/west
12:30	csd_	justin_smith: with multimethods, id still have to have the test function in the namespace defining the multimethod, which increases coupling
12:30	justin_smith	csd_: the issue is that for with-bindings to work the var needs to be dynamic, are you willing to make the var dynamic just so it is testable?
12:32	csd_	i dont see an issue but that obviously doesnt mean there isnt one
12:33	iwillig	have a core.async question. I am a little confused over the correct usage of put! vs (go (>! ..
12:34	iwillig	are they similar.. why would one want to use put over go >! or
12:34	crocket	justin_smith, Thanks
12:35	iwillig	to me it seems like put! allows you to introduction information into your async system without having to use go blocks. to they are usage at the edges of our async system.
12:35	iwillig	is that correct ? or roughly correct ?
12:42	csd_	is it possible to define a function where it looks for a particular var in the namespace its being called from, rather than the ns its defined in
12:44	snowell	csd_: You could write a getter function in the other ns and just call it?
12:45	csd_	snowell: id have to pass it as an arg though right?
12:45	snowell	Unless you mean dynamically determine the ns from which it's being called, which I imagine is difficult at best
12:45	csd_	the latter
12:45	csd_	ok
12:46	snowell	I imagine you'd have to figure out a way into the stacktrace of your function call, and I can't think of many things that sound less fun
12:46	csd_	sounds like id be fighting the language
12:46	snowell	Unless, as you said, you pass in the ns (or the value) when you call the function
12:47	justin_smith	csd_: why would the test function need to be in the same ns as the multimethod?
12:47	justin_smith	csd_: you can define an implementation of a multimethod from anywhere you like
12:47	csd_	justin_smith: the defmethods dont have to be in the same ns as the defmulti?
12:47	justin_smith	csd_: the only precondition being you can access the namespace that defines the multi dispatch
12:47	justin_smith	csd_: absolutely not
12:48	justin_smith	they wouldn't be very useful if that were the case
12:48	csd_	oh well thats nice
12:48	csd_	yeah
12:49	justin_smith	csd_: so you can write code that expects a thing that implements that multimethod, and pass in your custom or mocked up thing
12:49	csd_	yeah that sounds like a good way to go
12:49	justin_smith	much more versatile / reliable than a thread local binding imho
13:58	tmtwd_	http://pastebin.com/gGkpFn9W
13:59	tmtwd_	in this example "main" is the name of the html element, and it just coincidentally shares the name of the main function?
13:59	justin_smith	tmtwd_: that is what it looks like, yeah
13:59	justin_smith	main should do the same thing if you changed the name to foo
14:01	tmtwd_	ah, its just convention?
14:01	tmtwd_	not like a c main functoin or java?
14:01	justin_smith	tmtwd_: as far as I know, unless there is some lib or framework I don't know about that looks for main...
14:13	atomi	what can I use to make lein watch for file edits and rerun on save?
14:13	amalloy	rerun what?
14:13	atomi	"lein run"
14:14	amalloy	you want it to kill your existing program and start a new one? or wait in the background even when nothing is running, and start up lein run every time you save a file, or what?
14:15	atomi	kill and relaunch run
14:15	atomi	when code is updated
14:21	noncom	i am sorry for being alittle off-topic, but idk where else to ask
14:22	noncom	sometimes when i come here after a logout, the system tells me i have some mail
14:22	noncom	i then type in some command to read the mail
14:22	noncom	so, how do i leave such a mail for someone who's currently offline?
14:22	justin_smith	$mail noncom LIKE THIS!
14:22	lazybot	Message saved.
14:22	noncom	is that exclusively a #clojure channel feature?
14:23	noncom	rihgt, that's lazybot
14:23	justin_smith	it's a lazybot feature, it will work on other channels lazybot is on
14:23	noncom	thanks! :)
14:23	noncom	$seen ztellman
14:23	lazybot	ztellman was last seen quittingQuit: Computer has gone to sleep. 8 hours and 10 minutes ago.
14:31	atomi	so can I use a task runner to kill and relaunch lein run on code updates?
14:34	hiredman	why would you do that? clojure has a repl
14:36	atomi	hiredman: yeah
14:39	justin_smith	atomi: is the relaunching something for prod? if so, you might want jsvc - and seriously consider not even having lein installed on prod
14:40	atomi	justin_smith: yeah that's super helpful thanks
14:42	tmtwd_	nvm
14:44	tmtwd_	is there a rule of thumb for when we should or should not be returning values from functions?
14:44	justin_smith	tmtwd_: nil is a value, functions return values unless they throw an exception and thus never return
14:44	tmtwd_	ie (defn [x] (* x x) x) doesn't work, but in some functions we need to return values (mutable functions)?
14:45	justin_smith	(* x x) is a value
14:45	justin_smith	I don't get it
14:45	tmtwd_	(* x x) is the return value?
14:45	tmtwd_	then what is the tailing x?
14:46	justin_smith	no, that's not what I meant
14:46	justin_smith	I mean (defn f [x] (* x x)) also returns a value
14:47	tmtwd_	ah yeah, I agree there
14:47	justin_smith	when working with something immutable, return the new constructed value, if any - otherwise there is no way to do any meaningful work
14:47	tmtwd_	but I've seen some functions that use set! functions to modify the argument then it returns the argument
14:48	tmtwd_	it seemed kind of redundant to me
14:48	justin_smith	when working with something mutable, it can make sense to return the mutable thing after modifying it
14:48	justin_smith	tmtwd_: that's useful because of chaining
14:48	justin_smith	(-> x frob! munge! mangle!) for example
14:48	justin_smith	though of course we also have doto
14:49	tmtwd_	(defn [x] (* x x) x) so whats with this function, it doesn't crash
14:49	tmtwd_	but it doesn't do anything
14:49	tmtwd_	it just returns the input value?
14:49	justin_smith	it just does pointless work
14:49	tmtwd_	or the arg value?
14:50	tmtwd_	ah, it squares x, then returns the original value?
14:50	tmtwd_	hehe
14:50	justin_smith	right
14:50	tmtwd_	thanks
14:51	tmtwd_	it looked kindof similar to (defn [x] (set! x (* x x)) x)
14:51	tmtwd_	which I suppose would return the mutated value
14:51	amalloy	tmtwd_: that is just not a thing that is possible to do
14:51	tmtwd_	no, because clojure is immutable
14:51	tmtwd_	but if it were mutable...
14:53	justin_smith	tmtwd_: set! only works on vars and fields, you would need to do something different for that function to work (like dereffing x if it were a var)
14:53	tmtwd_	ah okay
14:53	tmtwd_	ah anyways, I now understand more than before thanks :)
14:55	Shayanjm	I want to write a set-of-maps output to stdout with formatting (i.e: strings should be wrapped in double quotes). If I println, I lose the double quote wrapping
14:55	Shayanjm	how do I go about outputting the set of maps with formatting so it can then be re-consumed?
14:55	snowell	Shayanjm: Put a `pr-str` inside your println
14:56	yedi	is there such a thing as a 0 size buffer for a core async channel
14:57	Shayanjm	snowell so (println (pr-str <thing>))?
14:57	snowell	Yup!
14:57	Shayanjm	thanks so much, trying now
14:59	Shayanjm	snowell: weird, that ends up printing an empty set for me
14:59	Shayanjm	retrying with just println
14:59	justin_smith	Shayanjm: snowell: (println (pr-str x)) is (prn x)
15:00	justin_smith	(doc pr-str)
15:00	clojurebot	"([& xs]); pr to a string, returning it"
15:00	justin_smith	(doc prn)
15:00	clojurebot	"([& more]); Same as pr followed by (newline). Observes flush-on-newline"
15:01	snowell	Huh. TIL
15:01	arohner	wasn't there a way to get prismatic/schema to return a validation error string, without throwing?
15:01	arohner	aha, s/check
15:02	justin_smith	arohner: oh nice, some of my unit tests are going to be much simpler / prettier now
15:02	justin_smith	(inc arohner)
15:03	lazybot	⇒ 2
15:20	jaen	Any hint what causes a validation failure like this `[{:medical-visits [(not (has-extra-elts? 1))]} nil]` in Prismatic's schema? I can't quite figure it out what this means.
15:23	justin_smith	jaen: unknown keys in the map, where :medical-visits was the only allowed key? Just a guess.
15:24	jaen	Hmm... I'll double check the keys then, but I have this as `:medical-visits [Visit]`, where the `Visit` schema validates without problem on it's own, so that would surprise me. Maybe the Grails backend is doing something weird.
15:25	jaen	Thanks for the pointer
15:49	gfredericks	has anybody else experienced cider causing emacs to hang for several seconds periodically?
15:49	gfredericks	this happened before I upgrade from 0.8.2 to 0.9.0 and is still happening
15:50	gfredericks	I should probably enable some kind of nrepl debugger to find out if it's sending stuff to the clojure process and if so what
15:51	atomi	how is sublimerepol?
16:16	gfredericks	looks like it's probably the cider repl buffer in particuler
16:32	justin_smith	gfredericks: there's so many ways that could happen, emacs is single threaded
16:32	justin_smith	the real solution would be to port core.async to emacs
16:35	wasamasa	oh, just around 2000 lines of clojurescript
16:35	wasamasa	clojurescript since as I understand it that's the portable variant since js implementations don't support threading either
16:36	justin_smith	right - I was at least half joking, but maybe it would work...
16:36	wasamasa	well, it would be interesting to have a macro compiling into all the callback hell you'd normally have
16:37	justin_smith	for sure
16:37	wasamasa	the other alternatives you have in emacs is using the abandoned threading branch, multiprocessing (which allows communication with the subprocess when emacs idles) and timer hacks to emulate deferred events
16:38	justin_smith	(dec timer hacks)
16:38	lazybot	⇒ -1
16:38	wasamasa	the multiprocessing option is the only officially supported thing and has been explored the most
16:39	wasamasa	networking behaves similiarly and only freezes up for me when it runs into an error condition
16:39	wasamasa	so that's may be what's happening
17:05	Guest17477	Are Clojure's "falsey" values defined anywhere? Is it just `false` and `nil`?
17:06	scgilardi	yes, there are docs about it. yes, just false and nil
17:06	justin_smith	Guest17477: yes, false and nil is the complete set
17:06	Guest17477	Thanks
17:07	justin_smith	Guest17477: seq is often used to make empty collections falsey (the idiom in common lisp)
17:07	justin_smith	(if (sex x) ...)
17:07	justin_smith	er, (seq x) of course
17:33	TimMc	...of course...
17:38	justin_smith	haha
17:59	gfredericks	,(defn =by ([k x] true) ([k x y] (= (k x) (k y))) ([k x y & zs] (apply = (map k (list* x y zs)))))
17:59	clojurebot	#'sandbox/=by
18:06	justin_smith	,(=by =by =by)
18:06	clojurebot	true
18:07	justin_smith	sadly as it does not have a single arity version, I cannot add any further =by without an error
18:08	justin_smith	,(=by (partial =by =by) =by =by =by =by =by =by)
18:08	clojurebot	true
18:08	gfredericks	(inc justin_smith)
18:08	lazybot	⇒ 264
21:02	devn	I am officially at my wit's end
21:02	devn	lein-environ and environ...
21:02	justin_smith	what are you trying to do?
21:02	devn	profiles.clj negates the use of jvm-opts in the project.clj
21:03	devn	removing profiles.clj means .lein-env gets written to empty map
21:03	justin_smith	devn: for some things I have found the need to use ^:replace for :jvm-opts
21:03	devn	it's just weird -- i guess im still not quite sure i understand HOW this is happening
21:04	devn	like, have i just missed the one permutation i haven't tried?
21:06	devn	justin_smith: what's that look like?
21:07	justin_smith	:jvm-opts ^:replace ["opts that replace, not merge, other opts go here"]
21:07	justin_smith	for example the "-server" arg only works if you use ^:replace
21:07	devn	which direction does the merge happen in?
21:08	devn	well, your stuff wins is what replace is, i guess
21:08	devn	so the default is the base wins?
21:08	justin_smith	devn: the rule I have heard is "most specific always wins"
21:09	justin_smith	so from least to most - global profiles.clj, project.clj, project profiles.clj iirc
21:09	devn	justin_smith: ugh, still didn't work
21:09	devn	so here's the specific setup -- i have lein-environ in my project plugins list
21:09	devn	and i have environ in the dependencies
21:10	devn	I need to set a java property in my project.clj so logback can pick it up for use in a configuration file
21:10	devn	because logging will be different in dev
21:10	devn	profiles.clj contains a couple of API keys
21:10	devn	and is also in the project dir
21:22	devn	so, lein-environ is the reaosn this is happening
21:22	devn	reason*
21:23	devn	https://github.com/weavejester/environ/blob/master/lein-environ/src/lein_environ/plugin.clj#L9
21:28	devn	...
21:28	devn	and then, he thought of something...
21:28	devn	so uh, im feeling kind of stupid, but man, why isn't this documented?
21:29	devn	you put your :jvm-opts [] in your local profiles.clj
21:35	creese	Can I use transit to write plain old JSON?
21:41	williamtaft	Can anybody help me with a question?
21:41	justin_smith	I bet someone can if you ask it
21:43	gfredericks	~anyone
21:43	clojurebot	anyone is anybody
21:43	gfredericks	~anybody
21:43	clojurebot	Just a heads up, you're more likely to get some help if you ask the question you really want the answer to, instead of "does anyone ..."
21:43	vikaton	wats dis clojure
21:43	williamtaft	Sure, I'm just seeming to have a little trouble. I'm using leinengen, and made a new file with the namespace project.foo.core - Now when i run lein repl, and switch into the project.foo.core namespace, I can't seem to access my symbol definitions.
21:44	gfredericks	(doto 'project.foo.core require in-ns)
21:44	justin_smith	williamtaft: switching to a namespace does not load it
21:45	justin_smith	williamtaft: unless you set things up explicitly, none of your code is automatically loaded into a repl (but it is all available via require, or load)
21:45	justin_smith	(that's why gfredericks' suggestion works)
21:45	williamtaft	ompilerException java.lang.RuntimeException: Unable to resolve symbol: doto in this context,
21:46	williamtaft	whoops
21:46	williamtaft	my far
21:46	williamtaft	t
21:46	justin_smith	williamtaft: (clojure.core/refer-clojure)
21:47	justin_smith	williamtaft: using in-ns when a namespace has not been loaded creates a broken namespace, but the above at least partially fixes it
21:48	williamtaft	hm, i should be able to (use 'namespace) then?
21:48	justin_smith	williamtaft: in-ns creates a namespace if it does not exist yet, but doesn't do any of the defautl namespace setup, like making clojure.core available
21:48	justin_smith	use will not be mapped into a broken namespace
21:48	williamtaft	yeah
21:48	justin_smith	clojure.core/refer-clojure fixes that
21:48	williamtaft	I'm restarting
21:48	justin_smith	restarting works too :)
21:49	williamtaft	(clojure.core/doto 'hello-world.db.core require in-ns)
21:49	williamtaft	shouldn't that work?
21:50	williamtaft	user=> (use 'hello-world.db.core) ;and shouldn't this work in the default namespace?
21:50	williamtaft	*user
21:51	justin_smith	williamtaft: unless src/hello_world/db/core.clj has some error in it, or cannot be found
21:51	justin_smith	note it has to be hello_world in the directory name (historical reasons) - this is a common newcomer mistake
21:52	williamtaft	src/hello_world/db/core.clj is its location
21:53	justin_smith	so yeah, unless the code has some problem, using that namespace should work as expected
21:53	williamtaft	do i need to set :gen-class in order for it to work in the repl?
21:54	justin_smith	requiring or using a file with a :gen-class in the ns should work as expected
21:54	creese	If I want to marshal data from postgresql to JSON, what lib should I use?
21:55	justin_smith	creese: I have had good luck with clojure.java.jdbc and cheshire
21:55	creese	Some of the data comes out of postgresql as not-a-string (i.e. UUIDs). Other times, I need to marshal certain fields (unix time to ISO8601)
21:56	justin_smith	creese: cheshire is good at doing the right thing, or letting you define new rules so it knows what to do with unfamiliar classes
21:58	williamtaft	http://pastebin.com/MbanaMTr
21:58	justin_smith	williamtaft: what's the gen-class for?
21:59	williamtaft	user=> (use 'hello-world.db.core)
21:59	williamtaft	CompilerException java.lang.IllegalArgumentException: Don't know how to create ISeq from: clojure.lang.Keyword, compiling:(hello_world/db/core.clj:1:1)
21:59	williamtaft	I didn't know if the repl needed to use it
21:59	justin_smith	williamtaft: the :require block needs to be inside parens
21:59	justin_smith	you only need :gen-class if you need a class that java code can call
22:00	williamtaft	i see
22:00	justin_smith	and even if calling from java, you will likely find it easier to write some java code that uses clojure.api
22:01	williamtaft	thank you! I'm pretty new to clojure, and still missing things
22:01	williamtaft	you need gen-class when making jars right?
22:01	justin_smith	yeah, and I know the error messages are often not particularly helpful (as seen above)
22:02	justin_smith	williamtaft: actually no - all you need to do is call "java -cp your-uber.jar clojure.main -m my.ns.core"
22:02	justin_smith	because clojure.main is a class java can invoke directly, and it knows how to load your code from source
22:03	williamtaft	ah
22:03	justin_smith	"lein uberjar" will complain that my.ns.core isn't a class in the compiled jar, but if invoked as above it just works
22:03	justin_smith	and not using gen-class actually makes things simpler
22:03	williamtaft	neat
22:07	monsta	good night, newbie here, question: how can I map a fn over a list of vectors lets say something like: ([1 2 3 4] [2 3 4])?
22:08	justin_smith	do you want to call the function once on each vector, or once on each element in each vector?
22:08	monsta	I would like to know both ways
22:09	justin_smith	,(for [v [[1 2 3 4] [2 3 4]] e v] (* e 2))
22:09	clojurebot	(2 4 6 8 4 ...)
22:09	justin_smith	that's the each element version, for is better there
22:10	justin_smith	,(map #(conj % :e) [[1 2 3 4] [2 3 4]])
22:10	clojurebot	([1 2 3 4 :e] [2 3 4 :e])
22:10	justin_smith	each vector version, map works
22:11	monsta	hmmm, let say that a have a function that accept n arity of vectors and I would like to map * to each elements of them, example?
22:12	justin_smith	,(for [v [[1 2 3 4] [2 3 4]] (apply * v))
22:12	clojurebot	#<RuntimeException java.lang.RuntimeException: Unmatched delimiter: )>
22:12	justin_smith	,(for [v [[1 2 3 4] [2 3 4]]] (apply * v))
22:12	clojurebot	(24 24)
22:14	monsta	the thing I would like to return the product of each vector passed
22:14	justin_smith	monsta: that's what that just did
22:15	justin_smith	or you mean element-wise?
22:15	justin_smith	,(map * [1 2 3 4] [2 3 4])
22:15	clojurebot	(2 6 12)
22:16	monsta	but isn't passing vectors to a defn give this example: ([1 2 3 4] [4 5 6]), not this [[1 2 3 ] [4 5 6]]
22:16	justin_smith	sure ##(apply map * [[1 2 3 4] [2 3 4]])
22:16	lazybot	⇒ (2 6 12)
22:17	monsta	let me try
22:17	justin_smith	also remember that ([1 2 3 4] [2 3 4]) is not valid input syntax (which is why I use square braces all around, but you could use quoting or list instead)
22:18	monsta	thank you so, much it worked.
22:41	hadronzoo	Do the dependencies in deps.cljs have to reside in /src? Is it possible to reference files in /resources?
22:42	justin_smith	hadronzoo: yes, and you can reference files that are on the classpath via project.clj too - any particular reason to put something under resources/ rather than src/ ?
22:43	justin_smith	oh sorry, deps.cljs - I should read more carefully
22:43	hadronzoo	I'm using lein-bower to import javascript libraries, but I'm not having much success.
22:43	justin_smith	I don't know about deps.cljs
22:48	hadronzoo	Does anyone know if an om-based select component exists? Something similar to react-select?
23:03	kLooaa	Do you realize that basically after age 20 your body starts rotting, being worse and worser at everything? and that includes your brain too? you will eventually be stupid and naive just like children. or worse - you can get alzheimer's disease. If you are alive now, I guarantee you that you will die eventually. And it can be really painful dying. Just read news or statistics how many people die in what ways DAILY. You will become one of them eventually.
23:03	kLooaa	One of that statistics number. nothing more.
23:03	justin_smith	kLooaa: and a good evening to you too!
23:04	kLooaa	I hate evenings
23:04	justin_smith	kLooaa: do you have any plans to do anything interesting before you whither away and die?
23:05	kLooaa	justin_smith: what interesting can do? if you know your ending very bad soon
23:05	justin_smith	no, no, we are talking about your death, not mine
23:06	kLooaa	eating food? watching tv? thats what humans do
23:06	kLooaa	yes about mine
23:07	justin_smith	kLooaa: fyi this channel is about Clojure, the programming language, not clojure, the psychological sense of coming to peace
23:08	justin_smith	err, closure is the coming to peace one, I am too used to typing out clojure in this channel
23:08	kLooaa	cloujure devs will die
23:08	justin_smith	but that isn't very clojure specific, is it?
23:09	kLooaa	i dont care clousure or not
23:09	kLooaa	DEAD
23:10	justin_smith	you are very determined for someone who doesn't care, seems like there is something you care about
23:11	kLooaa	yes I care about world existing
23:11	kLooaa	need to stop
23:31	adammh	I'd appreciate if anybody could help me with a `core.typed` question... just starting out so it may be a bit obvious
23:31	adammh	why does (IPersistentMap Integer myapp.core/Thing) Integer
23:32	adammh	match (t/Option (ILookup t/Any x)) t/Any
23:32	adammh	do I need to explicitly lift the map into the `Option` type?
23:36	WickedShell	I have a def that builds a java mig-panel (through seesaw) when I add it to my GUI via code that is loaded by lein its size comes out totally wrong, but if I paste the def into the repl and rebuild the GUI it works. (just rebuilding the GUI it doesn't fix the problem) http://pastebin.com/uFvMZMpH anyone have any ideas why that might happen?