#clojure – 2015-06-07

2015-06-07

03:34	cfleming	So I'm surprised to discover that the inferred type of the initialiser isn't propagated to :tag with plain def
03:35	cfleming	So (def x "Hello") (.length x) is a reflective call.
04:01	amalloy	cfleming: there was probably a time when :tag on vars was only for "function returning Foo", not actually "Foo"
04:02	cfleming	amalloy: Could be, yeah
04:02	cfleming	amalloy: BTW you asked a while ago about the type-inference augmented completion
04:03	amalloy	i remember
04:03	cfleming	amalloy: By far the most useful change turns out to be that on completion of something that looks like a field or method, I walk the local variables in scope and add completions from their classes.
04:04	cfleming	That gives you the completions you want 95% of the time
04:04	clojurebot	Huh?
04:04	amalloy	yeah, i bet
04:04	cfleming	I'm still going to add the order-swapping completion but I'm not sure it'll be as useful after this change
04:04	amalloy	but i imagine locals often aren't hinted well wnough to help?
04:05	cfleming	I'm not sure in general, mine are because I make sure I have no reflective calls
04:05	cfleming	But I'm the only one using this right now
04:08	cfleming	It does work very well for when you have chained calls, which is very common: https://twitter.com/CursiveClojure/status/606387674052575232
04:09	cfleming	(i.e. I obey the inferred types, not just the tagged ones)
04:14	amalloy	sure, of course
04:34	H4ns	does anyone remember the relatively recent blog post that showed the dramatic effects that missing type hints can have on performance? i'm unable to find it.
04:35	H4ns	also, can anyone recommend a intermediate level clojure book? i've tried two from packt only to get reminded that packt usually publishes crap.
05:06	cfleming	H4ns: Have you read Joy of Clojure?
05:06	cfleming	H4ns: I'd recommend that if you haven't.
05:06	H4ns	cfleming: thanks, i'll grab that!
05:27	anti-freeze	Hi everyone. I'm having issues with multimethods. I want to create a multimethod with a default value, depending on the argument provided. For example (create :users {:username "someone"}), if a :users create is defined, it should call that. Now thats standard multimethod behaviour, though I want to be able to define a default method, so in the case that :users method isn't defined, create is called on the :users collec
05:27	anti-freeze	tion. Any ideas?
05:29	TEttinger	cfleming was around recently, amalloy before that, and they're both pros. and now here's tbaldridge!
05:30	cfleming	Thanks for the vote of confidence TEttinger, but sadly I almost never use multimethods
05:30	TEttinger	same here
05:30	anti-freeze	Is there a better way to do this. Clojure noob here
05:31	anti-freeze	?*
05:32	TEttinger	anti-freeze, it's odd, multimethods are powerful but rarely written by many clojure users
05:32	TEttinger	I've never written one
05:33	anti-freeze	I feel like I'm taking a completely wrong approach. How do I handle default behaviour then?
05:33	TEttinger	I think there probably is a simple way, and it may involve multimethods
05:34	cfleming	anti-freeze: I actually seem to recall that multimethods allow you to use a :default dispatch
05:34	cfleming	anti-freeze: Yeah, they do: http://clojure.org/multimethods
05:34	anti-freeze	cfleming: Yea, they do, but I don't think they allow you to get the type the method was dispatched with
05:36	cfleming	anti-freeze: Sorry, that's all I've got :-(
05:36	anti-freeze	cfleming: Should I send you the sauce, maybe you can tell me why I can't seem to be able to clean this code up
05:37	cfleming	anti-freeze: Ok, refheap it up. I don't have long, but I'll take a look
05:39	anti-freeze	cfleming: https://www.refheap.com/102234 This is how I'm using stuff currently. I have for example a (defn all-* [coll] (...)) method that I make in to a partial. Seems like a shitload of duplication for pretty standard operations
05:41	cfleming	So "projects" is the name of a data store in mongo?
05:41	cfleming	Like a table or something?
05:41	cfleming	And you're doing this so you don't have to call (create-* "projects" ....)
05:41	cfleming	?
05:42	cfleming	anti-freeze: ^ ?
05:42	anti-freeze	cfleming: Pretty much
05:43	anti-freeze	cfleming: Its the same for every collection at the moment. The exact same copy-pasta for the users collection.
05:44	cfleming	anti-freeze: yeah, I don't think that's gaining you much. I'd just rename all-, create- etc to just add and create, and then use (create :projects ...)
05:44	cfleming	anti-freeze: The code reads the same, and you don't have that duplication
05:44	anti-freeze	cfleming: Yup... Alright, I just spent 2 days wasting my time. Thanks wunderhacker
05:46	cfleming	anti-freeze: Generally I'm a huge fan of keeping things as simple as possible. I almost never use partial, I'd rather have a little duplication and see what's going on.
05:46	cfleming	anti-freeze: Functional programming sometimes seems like a race to ultimate conciseness, but I'm not a fan
05:47	TEttinger	I am a fan though
05:47	TEttinger	440 chars or less
05:47	anti-freeze	TEttinger: do you have any ideas on the matter?
05:48	anti-freeze	Actually no, cfleming's argument is really valid
05:48	TEttinger	yes
05:48	TEttinger	I mostly make small laughably terse clojure snippets for IRC
05:48	TEttinger	,(let[a #(apply str(flatten %))r repeatedly p partition N rand-nth n #(a(N(concat(repeat %"")(mapcat p[1 2 3]%&))))v #(n 0"aioeu""iaai")w(fn[](let[b(n 6"!.""""...")s[(n 0"STKNYPKLG""GlThShNyFt""ZvrCth")(r(N[1 2])#(do[(v)(n 9(map str"'-"(r 2 v)))(n 0(concat"lpstnkgx"[(N["h""gl""gr""nd"])(v)])"rlthggghtsltrkkhshng")]))]][b(if(seq b)[" "s][(n 3",")" "(.(a s)toLowerCase)])]))](re-find #"[A-Z].+"(a[(r 500 w)"."])))
05:48	clojurebot	"Thirle'ong! Pagh piagek! Kauia-ond ying. Tholtiagg nyirk yurl shoggu'ong! Kaipult fti'agh tughia'ekh. Pegh... Thakhes tux sil, pok! Shasaig pugh. Ftiao ge-aitsai'egg! Lagh, gekhorl, sek, tais... Cthaioep, tasix, kugia'ol, pai-ughits. Zvrelt goguth gikh shang... Piashul kiats, nu-ap guth ftupep cthiag ftangiagr kot kax nyia-akhung, kughilt tun! Kiath ftotix ftosh goltait. Kiltugr koltash, yundailt...
05:48	TEttinger	&(let[a #(apply str(flatten %))r repeatedly p partition N rand-nth n #(a(N(concat(repeat %"")(mapcat p[1 2 3]%&))))v #(n 0"aioeu""iaai")w(fn[](let[b(n 6"!.""""...")s[(n 0"STKNYPKLG""GlThShNyFt""ZvrCth")(r(N[1 2])#(do[(v)(n 9(map str"'-"(r 2 v)))(n 0(concat"lpstnkgx"[(N["h""gl""gr""nd"])(v)])"rlthggghtsltrkkhshng")]))]][b(if(seq b)[" "s][(n 3",")" "(.(a s)toLowerCase)])]))](re-find #"[A-Z].+"(a[(r 500 w)"."])))
05:48	lazybot	⇒ "Gash cthailtoth, nyuth, gerlo'ogg! Shap gaipi-ait... Nox ctha'iand. Cthelt... Ftunilt, kug, na'iakh. No'ulus, kea! Kiarl! Thath... Nyerl, pia-eltaigg, laggol, piats! Tek ftel... Korl, kukha-osh thogg nyus lalog ftogh, te-ukh... Nyiang shaixog. Cthund... Nasoth gang... https://www.refheap.com/102235
05:48	TEttinger	to the refheap!
05:49	anti-freeze	I was going to define a macro and do a DSL to define operation groups and the use the (use-operations :default) to generate the methods
05:51	oddcully	you don't try to chant us an elder one?
05:52	anti-freeze	It's how the came up with the dragon word thingies in skyrim
05:52	anti-freeze	Clojure was used for skyrim
05:57	TEttinger	my favorite one-liner, srsly
05:57	TEttinger	lots of clojure features once you start being able to read that terse code
05:58	TEttinger	#(mapcat partition [1 2 3]%&)
05:58	TEttinger	that's a key one
05:59	TEttinger	(#(mapcat partition [1 2 3]%&) "ABCD" "ThChPhWh" "CthSprZvr")
05:59	TEttinger	&(#(mapcat partition [1 2 3]%&) "ABCD" "ThChPhWh" "CthSprZvr")
05:59	lazybot	⇒ ((\A) (\B) (\C) (\D) (\T \h) (\C \h) (\P \h) (\W \h) (\C \t \h) (\S \p \r) (\Z \v \r))
05:59	TEttinger	that's used throughout the snippet to get appropriate lengths of random letter sequences
06:00	TEttinger	never a Qj in there
06:28	H4ns	am i right in assuming that a type tag does not imply a cast in the java sense? i.e. if i have, say, a SQLConnection object which I know is a PGConnection, I need to both cast it and type tag it? (.getNotifications ^PGConnection (cast PGConnection conn))
06:30	TEttinger	H4ns, correct, a type hints are really just telling the compiler "this is currently this type, not a variable that could be any type" so the compiler knows what to do with it. but if the type hint doesn't match the actual type, it's ignored
06:31	H4ns	TEttinger: thanks!
06:32	H4ns	TEttinger: i wonder why the compiler does not know the type from the cast, though.
06:32	H4ns	(from the explicit cast, that is)
06:32	TEttinger	(doc cast)
06:32	clojurebot	"([c x]); Throws a ClassCastException if x is not a c, else returns x."
06:32	TEttinger	that would be why :)
06:34	H4ns	well, that implies that the returned value always has the class given as argument to cast, doesn't it?
07:05	cfleming	H4ns: In your example, you don't need the cast
07:05	cfleming	H4ns: In that case, the hint is effectively a cast
07:09	cfleming	H4ns: TEttinger is correct that type hints really just tell the compiler what the type of an expression is, but in your case the compiler will then use that hint to look up the method at compile time, and will cast the object automatically to invoke it.
07:10	sobel	TEttinger2: is that Klingon?
07:11	sobel	or Lovecraftian
07:11	H4ns	cfleming: thanks!
07:12	cfleming	H4ns: I do interop all day, and I've literally never used cast
07:13	H4ns	ok - i'll avoid it
07:13	H4ns	is there a way to access a record's field so that the type tag is preserved? if i use keyword lookup, it seems that the type tag that i established with defrecord is not seen by the compiler.
07:14	supersym	that shouldnt happen
07:14	H4ns	ah, ok, right. my fault, sorry
07:14	supersym	the use of 'type',
07:15	Bronsa	H4ns: there's no way to preserve it, the type tag is compiled away
07:15	supersym	or 'name' or whatever doesn't matter as those are bound in local scope, their meaning doesnt apply anymore
07:15	supersym	unlike other languages where use of 'class' or 'type' indeed causes problems
07:15	Bronsa	defrecord/deftype fields are stored in `Object` fields, no matter what you type hint them with
07:16	supersym	ah... type HINT .. different one
08:04	mearnsh	hi all! looking for some workflow advice: i'm working on a clj/cljs proj (via chestnut) w CIDER. right now i've got two nrepl connections going so i can eval my cljs in one (via weasel) and clj in the other. but CIDER doesn't play too nice with this since the default shortcuts send everything to just one of the repls (hence i can only eval my clj code successfully)
08:12	kwladyka	what is the difference in compojure between X-CSRF-Token and X-XSRF-Token? X-XSRF-Token is encrypted?
08:14	kwladyka	or there is no difference?
08:19	noncom	mearnsh: also try #clojurescript
08:19	mearnsh	yeah, thx
08:20	noncom	is it possible to make clojure map destructuring to work with string keys?
08:21	mearnsh	,(let [{:strs [k1 k2]} {"k1" 1 "k2" 2}] (prn k1 k2))
08:21	clojurebot	1 2\n
08:21	noncom	wow!
08:21	mearnsh	,(let [{:syms [k1 k2]} {'k1 1 'k2 2}] (prn k1 k2))
08:21	clojurebot	1 2\n
08:22	mearnsh	also
08:22	mearnsh	:)
08:22	noncom	wow, never really knew that!
08:24	mmeix	where would I find doc for :strs and :syms?
08:24	mmeix	(special forms?)
08:25	noncom	mmeix: i haven't seen the doc, hence i did not know.. but i guiess if you look at the source or the destructuring fn in clojure.core, they're there..
08:25	oddcully	mmeix: yes. section `Map binding destructuring`
08:25	noncom	*of the destructuring fn
08:25	mmeix	just found it: http://clojure.org/special_forms
08:25	noncom	is that a new feature or is it present already for a long time?
08:26	Bronsa	been there as long as :keys has
08:29	mmeix	I just made me a helper function, which puts vals of a map into vectors. {:foo 1} => {:foo [1]}, for using it with merge-with into afterwards ... is this reinventing some wheel. or does it exist in core? didn't find something so far ...
08:29	mmeix	,(defn vals->vector [m] (into {} (map (juxt key (comp vector val)) m)))
08:29	clojurebot	#'sandbox/vals->vector
08:30	mmeix	,(vals->vector {:foo 1})
08:30	clojurebot	{:foo [1]}
08:30	noncom	i think this is a kind of a deep merge
08:30	noncom	afaik people invent their own wheels for that
08:30	mmeix	,(apply merge-with into (map vals->vector {:foo 1} {:foo 2}))
08:30	clojurebot	#error {\n :cause "Wrong number of args (2) passed to: sandbox/vals->vector"\n :via\n [{:type clojure.lang.ArityException\n :message "Wrong number of args (2) passed to: sandbox/vals->vector"\n :at [clojure.lang.AFn throwArity "AFn.java" 429]}]\n :trace\n [[clojure.lang.AFn throwArity "AFn.java" 429]\n [clojure.lang.AFn invoke "AFn.java" 36]\n [clojure.core$map$fn__4555 invoke "core.clj" 262...
08:31	mmeix	,,(apply merge-with into (map vals->vector [{:foo 1} {:foo 2}]))
08:31	clojurebot	{:foo [1 2]}
08:31	noncom	yes, like this..
08:31	mmeix	ok
08:32	mmeix	goes into toolbox
08:33	mmeix	ah, ok: http://dev.clojure.org/jira/browse/CLJ-1468
08:34	mmeix	(what's better: building the own toolbox, using other's, or compiling other's?)
08:34	noncom	yeah, too many particularities.. many different possible usecases where you need slightly different behavior.. very hard to generalize..
08:34	mmeix	I see
08:35	kwladyka	toolbox is not up to date - dont use that
08:35	mmeix	flatland/useful seems to be ...
08:35	kwladyka	oh, i read that too fast - you are not talking about toolbox website :)
08:35	mmeix	no
08:35	noncom	in my toolbox i have many methods adviced by people on this channel, so you may say, that it is half-compiled from others and half my own
08:36	noncom	flatland is popular, yes
08:36	mmeix	ok - besides being a learning opportunity, each time :-)
08:40	mmeix	ah, flatland's merge-in looks great ... though I don't (yet) understand the (letfn [(merge-in* ...)] (defn merge-in ...)) construction there - homework for this evening, I guess
08:42	mmeix	a function can be defn-ed inside a (letfn ...) and is visible outside?
08:43	arkh	mmeix: you wouldn't want to do that though
08:43	mmeix	https://www.refheap.com/102239
08:44	mmeix	it's at least counertintuitive to me
08:44	mmeix	I thought everthing inside a local binding is invisible ...?
08:45	arkh	oh, ok. I guess they did it for the purpose of defining the function, as opposed to 'as an additional thing I'm doing inside a let'
08:45	arkh	def and defn create global bindings, even inside something lexically nested
08:45	dhardison	what's the difference in the syntax of using [] and a "do" or maybe nothing?
08:46	dhardison	i'm looking at some code that has [(if true) ...]
08:46	mmeix	so this is sort of very clever and self contained
08:46	arkh	mmeix: yes
08:47	mmeix	other way would have been to (defn merge-in* ..) and then using that in (defn merge-in ...) ?
08:47	arkh	dhardison: what you just wrote is creating a vector of something with contents that depend on the if condition
08:48	dhardison	arkh: makes sense, thank you
08:48	mmeix	arkh thanks for pointing out the global thing there
08:49	arkh	mmeix: what I would have done (which seems more boring me but I don't know if it's better or worse) is, instead of creating a function with letfn, I would have done a normal defn and used an anonymous function in place of merge-in*
08:49	mmeix	ah
08:49	arkh	^ *boring to me but I don't know if it's better or worse
08:49	mmeix	yes, that sounds more understandable/readable, at least for me
08:50	arkh	the upside with what they did is they gave an otherwise anonymous function a name, so maybe that's more readable
08:50	mmeix	aha!
08:51	arkh	but then I don't expect something lexically nested to be part of global scope, so maybe it's less readable for that reason
08:51	arkh	shrug : )
08:51	mmeix	this is what I didn't get when reading it first
08:51	mmeix	thanks for explanations!
08:52	arkh	you bet : )
08:56	dhardison	is there an easy way for me to print a list to the js console? doing js/console.log list prints some kind of clojure object -- i just want to see the contents
08:56	mmeix	flatland/useful is a learning ressource, I just found
08:56	gfredericks	dhardison: does prn work?
08:59	arkh	dhardison: if you put (enable-console-print!) before any print statements then those statements will send their output to the js console
08:59	dhardison	gfredericks: that did work - thank you. arkh i'll look at that too thank you.
09:06	mmeix	follow-up question: if I used a lib like flatland/useful in a clojurescript-project, using only few bits out of it, then the Google Closure compiler in advanced mode would remove unused functions as dead code, and so there would be no size penalty - is this correct?
09:06	mmeix	(maybe should ask this in #clojurescript)
09:07	arkh	mmeix: that is correct
09:07	mmeix	great
09:07	mmeix	thanx again
09:20	profil	is there a more clojury solution to this problem? (re-find #"(\d{4})(\d{2})(\d{2})T(\d{2})(\d{2})(\d{2})Z" "20150606T180000Z")
09:20	profil	a simple way to parse basic iso8601 dates
09:21	wink	I'd use joda time, maybe with a wrapper if there's one
09:22	arkh	I've always like clj-time
09:22	arkh	*liked
09:23	wink	and yes, it may sound like overkill to pull a lib for that.. but regarding time and date, I think it's usually worth it
09:24	profil	hmm, I wondering if it's worth it, the datestring _will_ always look like that
09:25	arkh	if you're not going to deal with more dates than that, re-find is still 'clojury' : )
09:27	profil	okay, thanks for the suggestions. Will stick with it for now, and change it when I need more in the future :)
09:28	oddcully	SimpleDateFormat?
09:32	oddcully	,(import 'java.text.SimpleDateFormat)
09:33	clojurebot	java.text.SimpleDateFormat
09:33	oddcully	,(.. (SimpleDateFormat. "yyyyMMdd'T'HHmmss'Z'") (parse "20150606T180000Z"))
09:33	clojurebot	#inst "2015-06-06T18:00:00.000-00:00"
09:34	arkh	nice
09:47	mmeix	flatland/useful.fn.annotate ... that's really useful! just wanted to express some spontanous happyness :)
09:52	arkh	I've used comp a number of times; never found a compelling reason to use juxt
09:53	arkh	it probably means I'm missing out
09:55	mmeix	I do find this useful:
09:55	mmeix	,(map (juxt :step :acc) [{:step 2 :acc :sharp :d "foo"} {:step 3 :d "foo"}])
09:55	clojurebot	([2 :sharp] [3 nil])
09:55	mmeix	pulling out relevant data from maps
09:56	arkh	I can see that
09:56	mmeix	just having learned about juxt a few days ago though ...
09:57	arkh	(hopefully what I wrote doesn't sound snarky - didn't mean it that way)
09:57	mmeix	no ... I'm always looking for education here for myself, being a beginner still
10:16	profil	oddcully: I am using clojurescript
10:16	gfredericks	why would I see a boxed math warning when loading a namespace in cider but not when running `lein do clean, test`?
10:18	jtmarmon	anyone know why compiling a 36 line compojure route would cause a stack overflow (compilation, not runtime)?
10:18	gfredericks	jtmarmon: nope; have you tried minimizing it to see what part causes the overflow?
10:20	jtmarmon	yeah i'm working on it & getting closer. one sec
10:28	jtmarmon	gfredericks: so there are two clauses in this let statement that seem to cause it. if i uncomment either i get the exception again. one is a datomic query, the other is a threading macro w/ 7 args
10:35	gfredericks	jtmarmon: welp maybe sharing some code would help
12:10	iamjarvo	i deleted a template from ~/.m2 and now lein wont fetch it automatically. I get "Failed to resolve version for"
12:19	justin_smith	iamjarvo: odd - did you only delete the template, or the template and pom etc.
12:19	iamjarvo	justin_smith i figured it out. I was typoing the template name using ctrl-r
12:19	iamjarvo	sad-face
12:20	justin_smith	aha, OK
12:20	iamjarvo	justin_smith but is that the right way to uninstall something? just delete it from ~/.m2
12:21	justin_smith	there isn't really a concept of "install" - but if you want to reduce the disk usage you may want to remove things you are not going to use again
12:21	justin_smith	I mean yeah there is a command "lein install" that puts something in your m2 cache, but it is more about caching things than installing them
12:25	iamjarvo	o ok, thank you
12:37	ionthas_	Why I cannot use (use 'midje.repl) from another namespace?
12:38	ionthas_	CompilerException java.lang.RuntimeException: Unable to resolve symbol
12:38	justin_smith	ionthas_: hmm, I would expect that error if you forgot to quote it
12:38	justin_smith	,(use foo.bar)
12:38	clojurebot	#error {\n :cause "foo.bar"\n :via\n [{:type clojure.lang.Compiler$CompilerException\n :message "java.lang.ClassNotFoundException: foo.bar, compiling:(NO_SOURCE_PATH:0:0)"\n :at [clojure.lang.Compiler analyze "Compiler.java" 6543]}\n {:type java.lang.ClassNotFoundException\n :message "foo.bar"\n :at [java.net.URLClassLoader$1 run "URLClassLoader.java" 366]}]\n :trace\n [[java.net.URLClass...
12:39	justin_smith	oh, no, that's a different error
12:39	kwladyka	https://www.refheap.com/102256 - what this code do and how to get this variable from other places?
12:39	justin_smith	what symbol can't it resolve?
12:39	kwladyka	it is from https://github.com/ring-clojure/ring-anti-forgery
12:39	ionthas_	justin_smit: It cannot resolve the function use.
12:40	justin_smith	ionthas_: did you use in-ns?
12:40	ionthas_	yes
12:40	justin_smith	(clojure.core/refer-clojure)
12:40	justin_smith	the problem is that in-ns doesn't load code
12:40	justin_smith	it simply creates an unusable empty namespace
12:40	kwladyka	ionthas_, http://clojuredocs.org/clojure.core/use
12:40	justin_smith	(unless the namespace was properly created before)
12:40	justin_smith	kwladyka: that's not the issue
12:41	justin_smith	kwladyka: he used in-ns, which leads to clojure.core not being referred properly
12:41	kwladyka	oh, sorry
12:41	kwladyka	just tried help :)
12:41	justin_smith	so he needs to explicitly spell out clojure.core in order to do anything useful
12:41	ionthas_	justin_smit: I didn't know that. Thanks :)
12:42	ionthas_	kwladyka: Also thanks to tou :P.
12:42	kwladyka	;)
12:42	justin_smith	ionthas_: for future reference, you probably want require in order to load your namespace, to make sure it exists before using in-ns
12:42	justin_smith	ionthas_: you can fix the broken ns (after refer-clojure) by doing (require 'some.ns :reload) which loads the ns file even though the ns already exists
12:43	ionthas_	thanks!
12:43	justin_smith	kwladyka: like any other var, you can access anti-forgery-token via the namespace it is in
12:43	justin_smith	kwladyka: of course it's special, because it is a dynamic bar with a per-thread binding
12:44	kwladyka	justin_smith, but how is it working? It is just (def anti-forgery-token) with extra metadata
12:44	justin_smith	,(def ^:dynamic foo)
12:44	clojurebot	#'sandbox/foo
12:44	justin_smith	,foo
12:44	clojurebot	#object[clojure.lang.Var$Unbound 0x1a6b32a1 "Unbound: #'sandbox/foo"]
12:45	justin_smith	that creates a var, with no value bound to it
12:45	justin_smith	,(binding [foo 1] (+ foo foo))
12:45	clojurebot	2
12:45	justin_smith	there, foo has a value
12:45	justin_smith	,foo
12:45	clojurebot	#object[clojure.lang.Var$Unbound 0x1a6b32a1 "Unbound: #'sandbox/foo"]
12:45	kwladyka	hmm so it is something like * (indicator) in C++?
12:45	justin_smith	but notice that the root of foo is still unbound
12:45	justin_smith	no
12:45	justin_smith	kwladyka: each thread has a different value for foo
12:46	justin_smith	unbound if it has not been bound yet, or whatever local binding is established
12:47	justin_smith	kwladyka: so the idea here is that ring-anti-forgery can let your app's handler know the token to render into the html via dynamic binding, and then it checks for that same dynamically found var coming back on the client's request
12:47	justin_smith	it prevents replay attacks
12:49	kwladyka	mmm still i feel a little magic :) In which moment in the code the value is generated?
12:49	kwladyka	(binding ...) ?
12:49	justin_smith	kwladyka: hidden somewhere in the anti-forgery middleware
12:50	kwladyka	oh.... right :)
12:50	justin_smith	kwladyka: https://github.com/weavejester/ring-anti-forgery/blob/master/src/ring/middleware/anti_forgery.clj#L67
12:50	justin_smith	that's where it happens
12:51	justin_smith	and I showed above how binding works (creates a value for a def that is only valid for one block of code, in one thread)
12:51	justin_smith	kwladyka: binding / dynamic vars is still kind of magic, and many people have convincing args that they should be avoided
12:52	justin_smith	eg. http://stuartsierra.com/2013/03/29/perils-of-dynamic-scope
12:55	kwladyka	ok, i added this to bookmark to read in free time, thank you
12:56	justin_smith	the important part for understanding that anti-forgery code is that via dynamic binding a symbol var can be used to represent different tokens in each thread
13:01	kwladyka	so use this var should looks like that (:require [ring.middleware.anti-forgery :refer anti-forgery-token]) ? i guess not, because it doesnt work :)
13:01	justin_smith	kwladyka: that's not how refer works
13:01	justin_smith	you need a vector
13:01	kwladyka	?
13:02	justin_smith	,(require '[clojure.string :refer join])
13:02	clojurebot	#error {\n :cause ":only/:refer value must be a sequential collection of symbols"\n :via\n [{:type java.lang.Exception\n :message ":only/:refer value must be a sequential collection of symbols"\n :at [clojure.core$refer doInvoke "core.clj" 4086]}]\n :trace\n [[clojure.core$refer doInvoke "core.clj" 4086]\n [clojure.lang.RestFn applyTo "RestFn.java" 139]\n [clojure.core$apply invoke "core.clj...
13:02	justin_smith	that's the version that fails
13:02	justin_smith	,(require '[clojure.string :refer [join]])
13:02	clojurebot	nil
13:02	justin_smith	it works with a vector
13:02	kwladyka	oh true.... sorry, i am learning a lot and sometimes i forgot about basic things...
13:03	justin_smith	(join ", " ["hello" "world"])
13:03	justin_smith	,(join ", " ["hello" "world"])
13:03	clojurebot	"hello, world"
13:03	kwladyka	yeah, it works :)
13:16	mmeix	building a function, which creates a run between two numbers, but inclusive the higher num, and self-sorting:
13:16	mmeix	,(let [range-incl (fn [a b] (apply range (map + ((juxt min max) a b) [0 1])))] (range-incl 11 -3))
13:16	clojurebot	(-3 -2 -1 0 1 ...)
13:16	mmeix	good solution?
13:18	mmeix	,(defn range-incl [a b] (apply range (map + ((juxt min max) a b) [0 1])))
13:18	clojurebot	#'sandbox/range-incl
13:18	mmeix	,(range-incl 5 -2)
13:18	clojurebot	(-2 -1 0 1 2 ...)
13:24	kwladyka	,(range-incl 5 5)
13:24	clojurebot	(5)
13:25	mmeix	which is ok
13:25	mmeix	for my use-case
13:27	kwladyka	mmeix, (range (min -2 5) (inc (max -2 5))) - maybe something in that style?
13:27	kwladyka	should be more readable?
13:27	mmeix	right you are
13:58	dhardison	what's the best way to look up browser dom elements using clojure?
13:59	justin_smith	dhardison: you'll likely get more help in #clojurescript, but you can use any method that works in js, in my experience it's better to use react so you don't have to look up elements
13:59	justin_smith	(well, reagent or om, which use react)
13:59	dhardison	i see - i'll take a look thank you
15:18	dhardison	can i store a keyword into a variable using let (e.g. (let [keyword :black] ... ) i'm geting a compile error atm but maybe it's not related to that
15:21	farhaven	,(let [foo :bar])
15:21	clojurebot	nil
15:21	farhaven	seems to work
15:21	farhaven	,(let [foo :bar] foo)
15:21	clojurebot	:bar
15:22	j-pb	hu?
15:23	farhaven	that was in reply to dhardison
15:23	j-pb	ah sorry, I missed the top part, and was wondering if you had a question :)
15:37	sy	when working with leiningen and the cider nrepl i notice that if i modify a .clj file that provides a required namespace in another file, the file containing the required nmespace isn't re-loaded and re-compiled by lein or cider
15:37	sy	should i expect it be re-loaded ?
15:40	justin_smith	sy: what are you doing to make reload happen?
15:44	sy	if file1.clj requires a namespace in file2.clj, file2.clj gets compiled when i start cider, if i (load ...) the namespace in file1 again, file1 gets compiled but required namespace in file2 isn't re-compiled, i am missing a clue about this simple project management
15:45	justin_smith	sy: the point of require is that it does nothing if the file you required is already loaded
15:46	justin_smith	sy: instead of (load ...) use (require ... :reload-all) to cause it and all it's dependencies to be reloaded
15:46	justin_smith	there is no way to force reload of namespaces that require a given namespace though
15:51	sy	ah... i knew there was a way, reminds me of lisp and ASDF, there is syntactic wizardy required :)
15:51	sy	Recognized flags: :reload, :reload-all, :verbose
16:22	verma_	not sure if this is the right channel for this, but what controls the indentation of methods defined under defrecord?
16:23	verma_	I want them to indent like defn, but the first statement indents right under the parameter list
16:23	verma_	tried the clojure-backtracking-indent stuff, but no luck so far
16:28	justin_smith	verma_: indentation by whom?
16:29	verma_	oh sorry, didn't realize I never mentioned the context, clojure-mode under emacs.
16:29	verma_	justin_smith: ^
16:31	sy	this is interesting about namespaces and multiple sources files and the jvm --> https://github.com/clojure/tools.namespace#reloading-code-motivation
16:32	justin_smith	verma_: the default indent rules are all defined in clojure-mode.el
16:34	verma_	justin_smith: yeah I am trying to change them, it seems the computer I am on has a more recent version of clojure-mode, so its doing the indentation differently, can't really understand what the clojure-backtracking stuff means :(
16:44	amalloy	verma_: are you writing your defrecords incorrectly?
16:45	amalloy	clojure-mode indents correct code correctly, but if you write illegal code it won't understand how to indent
16:50	verma_	amalloy: could be the reason, things have stopped working :(
16:50	verma_	amalloy: checking ..
16:53	dhardison	can i do an if statement within a let variable declaration similar to what you can do with a list?
16:56	H4ns	dhardison: you mean (let [a (if foo 1 2)] ...) ? or what?
16:56	dhardison	H4ns: yes
16:56	H4ns	dhardison: yes. `if` is not a statement, and an if form is just an expression.
16:57	H4ns	dhardison: there are no statements in clojure, for what it is worth.
16:58	sy	binding-form init-expr
16:58	sy	exprs are meant for evaluation
17:04	j-pb	and thats just what they'll do
17:31	gfredericks	hello
17:34	m1dnight_	Is there an up to date guide on clojure SQL?
17:34	m1dnight_	I cant seem to get it working anymore. Been a while since I tinkered with this code.
17:35	verma_	justin_smith, amalloy: this is the indentation I get: https://gist.github.com/verma/69c407f9621154288d6a
17:35	m1dnight_	I was trying the basics like creating and reading but I can only seem to create a database. Reading always returns nil.
17:35	verma_	the method bodies are aligned with arguments :(
17:35	gfredericks	m1dnight_: what's "clojure SQL"?
17:35	verma_	looking at some of the examples on clojuredocs, it seems that's what its supposed to be?
17:36	amalloy	verma_: weird. do you have backtracking indent turned on?
17:36	m1dnight_	oh, right. I'm talking about jdbc here. (clojure.java.jdbc)
17:36	m1dnight_	Im trying to play with a postgresdb
17:36	amalloy	that's the feature that's supposed to make it indent defrecord sensibly
17:37	gfredericks	m1dnight_: (jdbc/query conn ["SELECT 1"])?
17:37	m1dnight_	all nil :p
17:37	m1dnight_	I dont get it. Queries to create tables work though..
17:37	m1dnight_	I must be missing something stupid here..
17:38	verma_	amalloy: I am trying to set it up so that it doesn't do that, with no success, seems to me like its a recent change, since the version of clojure-mode I have on my notebook isn't doing this
17:38	gfredericks	m1dnight_: my guess is there's some weird other problem
17:38	m1dnight_	Also, I checked in pgadmin and there is actual data in the database.
17:38	gfredericks	m1dnight_: because SELECT 1 should not return nil under like any dang circumstances
17:39	verma_	going to take a look at what the nodebook version is doing to clojure-backtracking-indent
17:39	m1dnight_	But when I execute the following (on an existing db): (sql/insert! (read-db-config) "testing" {:data "fobar"})
17:39	m1dnight_	ClassCastException clojure.core$identity cannot be cast to clojure.lang.Named clojure.core/name (core.clj:1518)
17:39	m1dnight_	that happens. (Yes, the (read-db-config) function returns valid credentials, otherwise the create table wouldnt work, I assume)
17:40	m1dnight_	Ill give sqlite a shot perhaps.
17:55	verma_	amalloy: ok, so the version installed on my notebook seems to be behaving correctly, I upgraded it, and it started doing the unwanted indentation again, guess I will just revert to an older version and carry on, no changes to any backtracking indentation, but seems like there was a change to backtracking regexs to account for namespace names.
17:55	verma_	I think that's why people freeze versions of packages they use, to avoid unnecessary problems :(
17:56	amalloy	yes. i run clojure-mode off a very old git checkout plus some changes i made, just because i'm not really interested in whatever new stuff comes out
20:14	gfredericks	okay so I've evolved into this workflow where I run my clj repl process with docker, and connect to it with cider
20:14	gfredericks	I'm not sure if the docker part is important, but one way or another I find myself restarting the repl a few times a day at least
20:15	gfredericks	maybe more often if I debugging something where processes hang
20:15	gfredericks	and cider seems to make it very difficult to reconnect
20:15	gfredericks	I have to manually close the buffer of the disconnected process to keep cider from nagging me about existing connections when I try to reconnect
20:15	gfredericks	does anybody else do this better?
20:25	gfredericks	I think the best option would be some way to get it to reconnect when the repl becomes available, reusing the buffer
21:06	gfredericks	okay big mystery here um
21:06	gfredericks	I'm using a lib and a var is mysteriously not defined
21:06	gfredericks	I can open the jar and see its defn there
21:06	gfredericks	I can also verify from the repl other changes unique to that jar so I can't imagine anything else running
21:07	gfredericks	I rm -rf'd the target before starting the repl
21:07	gfredericks	this is all physically impossible
21:07	amalloy	gfredericks: are you actually running the jar you have inspected, and not some other jar? are you ssh'd into a different machine accidentally?
21:09	gfredericks	now I'm looking at line metadata on the vars to see if that correlates with the file I'm looking at
21:11	gfredericks	the pom.properties file on the classpath says everything is normal
21:11	gfredericks	the line numbers are super weird though o_O
21:12	gfredericks	they don't correspond to any reasonable version of the lib
21:12	gfredericks	hold up gonna try this on a totally different computer via `lein try`
21:13	amalloy	gfredericks: have you checked that lein classpath points at the jar you think it does?
21:13	amalloy	some dependency may be pulling in a different version
21:14	gfredericks	that wouldn't explain "pom.properties" though no?
21:14	amalloy	man i dunno what this pom.properties nonsense is
21:15	gfredericks	okay
21:16	gfredericks	everything works fine with `lein try` so I guess it's specific to this project and not the lib
21:16	gfredericks	now for `lein classpath`
21:16	gfredericks	yes indeed there is a dumber version of the project earlier in the classpath wtf.
21:17	gfredericks	oh I see yep yep
21:18	gfredericks	it's cuz I'm using a fork with a different group id
21:18	gfredericks	so my explicit declaration didn't override the indirect dep with the normal group id, and an older version
21:18	justin_smith	gfredericks: which is a good argument against namespaces that don't include the group
21:18	gfredericks	physics is working correctly
21:19	justin_smith	gfredericks: that's a releif
21:19	gfredericks	justin_smith: it's a temporary fork
21:19	gfredericks	I wouldn't want to renamespace anything
21:19	justin_smith	gfredericks: oh, OK
21:19	justin_smith	I was thinking of when I did some work I component
21:19	justin_smith	I moved it from com.stuartsierra.component to org.noisesmith.component