#clojure – 2015-06-04

2015-06-04

00:23	Seylerius	There a good clojurish way to spawn virtual machines to accomplish a specific task?
00:26	TEttinger	hey Seylerius, did you get the sudoku solver GUI working?
00:26	Seylerius	TEttinger: Been busy with errands all damn day, so no, unfortunately.
00:26	Seylerius	Planning on taking another whack at it tomorrow.
00:26	TEttinger	cool
00:27	Seylerius	Oh, btw, why is your clone always hanging in here?
00:27	Seylerius	TEttinger: It kinda throws off tab-completion on your nick.
00:28	TEttinger	TEttinger2? logger bot, I run an irc bot on an old laptop and I keep an irc client open as well so I can check if it's working
00:28	TEttinger	err
00:28	TEttinger	TEttinger2 is not actually a bot, it's the client
00:28	heurist	Seylerius: just set your irc client to complete based on last spoken instead of alpha.
00:29	TEttinger	or shortest first
00:29	TEttinger	but TEttinger leaves, TEttinger2 does not
00:29	TEttinger	ok, time to get this cluajure obscene hybrid working
00:29	Seylerius	TEttinger, heurist: The problem isn't that, the problem is that it just provides the common prefix, which leaves me retyping the ": " every time.
00:30	TEttinger	ahhhhh
00:30	Seylerius	TEttinger: Cluajure? Sounds like an abomination.
00:30	Seylerius	(In other words, I'm being lazy)
00:31	Seylerius	I'm heading out to town. See y'all later, maybe tomorrow.
00:31	Seylerius	heurist: It's ERC, so I just have to configure it a little differently.
00:31	Seylerius	Again, I've been lazy.
02:44	dfletcher	added my first code sample to clojuredocs.org today :) http://clojuredocs.org/clojure.core/condp#example-556fc440e4b03e2132e7d185
02:47	dfletcher	also heh I never really noticed by my github qrcode thingy looks like a space invader.
02:47	dfletcher	*but my
02:49	dfletcher	condp makes all the other solutions to fizzbuzz look like a big joke heh.
02:50	amalloy	dfletcher: not really. it's much nicer with a loop over the divisor list
02:50	dfletcher	example?
02:52	amalloy	,(let [divisors [[15 "fizzbuzz"] [3 "fizz"] [5 "buzz"]]] (defn fizzbuzz [n] (-> (first (for [[r s] divisors :when (zero? (mod n r))] s)) (or (str n)))))
02:52	clojurebot	#'sandbox/fizzbuzz
02:52	amalloy	,(dorun (map (comp prn fizzbuzz) (range 1 30)))
02:52	clojurebot	"1"\n"2"\n"fizz"\n"4"\n"buzz"\n"fizz"\n"7"\n"8"\n"fizz"\n"buzz"\n"11"\n"fizz"\n"13"\n"14"\n"fizzbuzz"\n"16"\n"17"\n"fizz"\n"19"\n"buzz"\n"fizz"\n"22"\n"23"\n"fizz"\n"buzz"\n"26"\n"fizz"\n"28"\n"29"\n
02:53	amalloy	,(clojure.string/join " " (map fizzbuzz (range 1 31)))
02:53	clojurebot	"1 2 fizz 4 buzz fizz 7 8 fizz buzz 11 fizz 13 14 fizzbuzz 16 17 fizz 19 buzz fizz 22 23 fizz buzz 26 fizz 28 29 fizzbuzz"
02:55	J_A_Work	personally, my favorite FB is with javascript, because switch case can fall through, so you can write it with only the conditionals on mod 3 and 5
02:56	amalloy	the nice thing is that now the divisors are just data, a list you could replace without having to re-define fizzbuzz if you wanted different numbers, and the various bookkeeping is separate from the specific rules
02:57	dfletcher	yeah I like it. also heh thanks for zero? updated my sample
02:59	lumafi	how about fizzbuzz without any conditionals?
02:59	lumafi	,(def fizzbuzz (letfn [(fb [s k coll] (mapcat (fn [x] (cons s (rest x))) (partition k coll)))] (->> (range) (fb "fizz" 3) (fb "buzz" 5) (fb "fizzbuzz" 15))))
02:59	clojurebot	#'sandbox/fizzbuzz
03:00	lumafi	,(clojure.string/join " " (take 30 fizzbuzz))
03:00	clojurebot	"fizzbuzz 1 2 fizz 4 buzz fizz 7 8 fizz buzz 11 fizz 13 14 fizzbuzz 16 17 fizz 19 buzz fizz 22 23 fizz buzz 26 fizz 28 29"
03:00	dfletcher	actually I retract my earlier statment and ammend it. clojure makes other solutions to fizzbuzz look like a joke hehe
03:01	amalloy	that's a cute one, lumafi
03:02	dfletcher	zero is a weird case it matches all
03:04	dfletcher	when i tried it as an infinite seq ended up using (rest range) to start with since 0 doesn't make tons of sense
03:04	dfletcher	*to start with 1
03:07	dfletcher	man. i understood amalloy's one pretty quick. this one is making me look up thinigs and I still have no idea whats going on heh.
03:08	amalloy	dfletcher: do you want a hint or to figure it out yourself?
03:08	dfletcher	i like a puzzle i'll ask if I want help hehe
03:10	dfletcher	thanks for asking though rather than just answering it. just feeling chatty this eve :)
03:12	mmeix	Beginner's question: I have [ {:a 1} {:a 2} {:a 3} {:b 5} {:b 6} {:c 99} ] and I want to get [ {:a [1 2 3] {:b [5 6]} {:c [99]} ] - what would be the fn to use with merge-with in this case?
03:12	mmeix	(obviously conj and concat etc wouldn't work)
03:13	TEttinger	(doc merge-with) ; let's see...
03:13	clojurebot	"([f & maps]); Returns a map that consists of the rest of the maps conj-ed onto the first. If a key occurs in more than one map, the mapping(s) from the latter (left-to-right) will be combined with the mapping in the result by calling (f val-in-result val-in-latter)."
03:13	amalloy	mmeix: in fact concat does work (though i recommend into instead), as long as you pre-process the sequence ahead of time
03:14	mmeix	ah, ok
03:14	amalloy	try something like this: (apply merge-with into (for [m [{:a 1} ...]] ...))
03:15	mmeix	ok, wrapping my brain around this - thanks!
03:29	benhuda	hello
03:30	benhuda	do you think it is wise to name an open source library "kevlar" given that Kevlar is registered trademark?
03:31	amalloy	well on the one hand you would be safeish on trademark infringement, since there is no danger of someone confusing your clojure library for actual physical kevlar. on the other hand there's nothing stopping them from suing you anyway
03:31	benhuda	yes i just bumped into some lawsuit for kevlarftp (OSS) which was named to kftp after lawsuit threats
03:33	benhuda	i'll just call it 'armor' then :)
03:35	dfletcher	oh oh I get it! partition is breaking it into sets of 3,5,15. then replace the first element of each partitioned bit with the string. then cons to stitch it all back together. genius! thanks for that lumafi
03:36	TEttinger	kavler
03:36	TEttinger	cavalier
03:39	dfletcher	err, mapcat to stitch it back together, cons is doing the string replacement thingy. ok after midnight i'm a pumpkin now. night peeps.
03:44	TEttinger	&(let [r (range 100) matching (fn [n s] (map #(if (zero? (mod % n)) s "") r) fizz (matching 3 "fizz") buzz (matching 5 "buzz") fizzbuzz (map str fizz buzz)] (map #(if (empty? %1) %2 %1) fizzbuzz r))
03:44	lazybot	java.lang.RuntimeException: Unmatched delimiter: ]
03:44	TEttinger	aww
03:45	TEttinger	&(let [r (range 100) matching (fn [n s] (map #(if (zero? (mod % n)) s "") r)) fizz (matching 3 "fizz") buzz (matching 5 "buzz") fizzbuzz (map str fizz buzz)] (map #(if (empty? %1) %2 %1) fizzbuzz r))
03:45	lazybot	⇒ ("fizzbuzz" 1 2 "fizz" 4 "buzz" "fizz" 7 8 "fizz" "buzz" 11 "fizz" 13 14 "fizzbuzz" 16 17 "fizz" 19 "buzz" "fizz" 22 23 "fizz" "buzz" 26 "fizz" 28 29 "fizzbuzz" 31 32 "fizz" 34 "buzz" "fizz" 37 38 "fizz" "buzz" 41 "fizz" 43 44 "fizzbuzz" 46 47 "fizz" 49 "buzz" "fizz... https://www.refheap.com/102078
03:45	TEttinger	it's always nice to write fizzbuzz
03:46	TEttinger	different ways every time
03:51	H4ns	how can i, in cider, achieve that a macro expansion (C-c C-m) is not elided using #?
03:51	H4ns	C-c M-m that is
05:28	kungi	I updated compojure from 1.2.0 to 1.3.4 and the order of the keys/vals in (:roles (friend/current-authentication)) reversed?
05:29	kungi	O.o
05:30	Empperi	kungi: you cannot rely on map value ordering
05:30	Empperi	not unless you are using a sorted map
05:30	Empperi	https://clojuredocs.org/clojure.core/sorted-map
05:31	TEttinger	or an ordered map, which doesn't come with clojure and is in flatland
05:31	kungi	Empperi: not the ordering of the map. The keys and values reversed
05:31	kungi	Keys are now values and the other way around
05:31	TEttinger	hm
05:31	Empperi	well that sounds strange
05:32	TEttinger	that would break all sorts of things if there were duplicate values before: ##(hash-map :a 1 :b 1)
05:32	lazybot	⇒ {:b 1, :a 1}
05:32	TEttinger	totally fine, but
05:32	TEttinger	##(hash-map 1 :a 1 :b)
05:32	lazybot	⇒ {1 :b}
05:32	TEttinger	,{1 :a 1 :b}
05:32	clojurebot	#<IllegalArgumentException java.lang.IllegalArgumentException: Duplicate key: 1>
05:33	TEttinger	the function hash-map is more lenient than the literal
05:38	kungi	... I think it's my fault because of my get-roles-for-user function ...
05:40	ionthas_	What is the neatest way to define default values for a function? Right now I'm using arity and I call the function with the default parameter value.
05:41	Empperi	that is pretty much the neatest way except if you pass in a map and want to provide default values for keys
05:41	Empperi	,((fn [{:keys [foo bar] :or {foo 1 bar 2}}] [foo bar]) {:foo 15})
05:41	clojurebot	[15 2]
05:42	Empperi	in that case it's better to use that part of destructuring syntax
05:42	Empperi	as one might expect, works everywhere where destructuring works
05:43	ionthas_	Thanks Empperi :)
05:43	Empperi	np
05:45	danielcompton	@cfleming: you around?
05:48	kungi	Found it!
05:52	mmeix	amalloy recommended "into" instead of "concat" for use in merge-with - what are the advantages of into vs. concat?
05:52	mmeix	(besides looking neat)
05:52	justin_smith	mmeix: hash-maps are strict, concat is lazy
05:53	justin_smith	it's usually a bad idea to mix strict and lazy unless you have a specific reason to
05:53	mmeix	I see
05:53	justin_smith	see also stuartsierra's blog post on concat
05:54	justin_smith	http://stuartsierra.com/2015/04/26/clojure-donts-concat
05:54	mmeix	If I'm foreseeing, that I will consume the whole data, lazyness buys me nothing inthis case - right?
05:54	justin_smith	right
05:54	mmeix	ah - thanks for the article!
05:54	justin_smith	unless the data is too large to be in memory all at once
05:55	justin_smith	mmeix: it's a good blog to follow for clojure
05:55	mmeix	my data is mostly around 5-20 elements
05:55	justin_smith	yeah, staying strict will keep it simpler than
05:55	justin_smith	*then
05:55	mmeix	great advice, as ever :-)
06:00	kungi	Empperi: you where right. I depended on the order of entries in a map. It was a bit hidden in the code
06:01	cfleming	danielcompton: Yep, what's up?
06:02	kungi	Is there a standardlibrary function to (select-vals {:a 1 :b 2 :c 3} [:a :c]) -> [1 3]
06:07	mmeix	I have a second question, loosely related: for my current project (music typesetting with svg in clojurescript) I built a couple of basic functions, and a bigger one, which uses them to build a combined graphical group (a chord, consisting of several noteheads, accidentals, stem flags/beam, dots etc.) with many calculations in it, depending on each other; this makes sense as a semantic unit and building block for the next higher
06:07	mmeix	level. Now for spacing several of these units in a row (staff) I need to ask the group about its dimensions, which would have to be calculated out of the elements in it - this begins to sound like an object with a function "return-size" or something like that in it. What would be a proper Clojure solution to expose this to the next higher function?
06:12	mmeix	, (map {:a 1 :b 2 :c 3} [:a :c])
06:12	clojurebot	(1 3)
06:12	mmeix	(for kungi)
06:12	justin_smith	alternately ##((juxt :a :c) {:a 1 :b 2 :c 3})
06:12	lazybot	⇒ [1 3]
06:13	TEttinger	juxt!
06:13	TEttinger	juxtin_smith
06:13	kungi	mmeix: justin_smith thank you :-)
06:13	TEttinger	(inc mmeix)
06:13	lazybot	⇒ 1
06:13	TEttinger	(inc justin_smith)
06:13	lazybot	⇒ 258
06:13	mmeix	my first inc :-)
06:13	justin_smith	TEttinger: eventually I will have to implement juxt-in
06:13	TEttinger	this-juxt-in
06:14	justin_smith	that's the version for protocols, of course
06:14	ddellacosta	omg
06:14	ddellacosta	you guys are such dorks
06:15	justin_smith	mmeix: are the graphical elements nested like a tree? if so you may want to do a tree walk and either a thing knows its width, or can find out the width from its children, recursively
06:16	mmeix	they are not nested, but dependent on each other via some rules for placement
06:16	justin_smith	mmeix: oh, then that sounds like a reduce
06:17	justin_smith	each one figures out what its right edge in, based on the prior state, and passes that forward
06:17	justin_smith	s/in/is
06:17	mmeix	aha ... have to ponder this for a while ...
06:19	mmeix	that means, my group has to collect these measurements inside in a neatly accessible way, and expose it as an additional return value, in a map or something like this)
06:21	mmeix	and since I'll need the dimensions anyway, the "object" should calculate it alongside all the placement and return it with them - is this right thinking?
06:21	justin_smith	I think so
06:21	mmeix	ok - thanks!
06:24	mmeix	does anyone have a good source for algorithms for overlap detection of shapes (consisting of horizontal/vertical straight lines only)?
06:25	mmeix	(expressed in x/y coords, of course)
06:26	TEttinger	if the line is vertical, check if its x is between the end and start of any horizontal lines, and if its x is identical with any other vertical lines
06:26	TEttinger	if the line is horizontal, check if its y is between the end and start of any vertical lines, and if its y is identical with any other horizontal lines
06:27	mmeix	and do this for any combination ...?
06:27	mmeix	I see
06:27	TEttinger	I mean that's super naive, but each check should be very fast
06:27	TEttinger	you can end early if you're doing a reduce, see ##(doc reduced)
06:27	lazybot	⇒ "([x]); Wraps x in a way such that a reduce will terminate with the value x"
06:28	TEttinger	so if you know you overlap, you don't need to keep checking
06:28	mmeix	I didn't know about early ending in reduce
06:28	mmeix	more to learn
06:28	mmeix	thanks again
06:30	justin_smith	yeah, it's easy to get it mixed up, because we have something called "for", but reduce really ends up being the idiomatic replacement of for in other languages in most cases
06:31	mmeix	I get the notion, that for is seldomly the best solution in Clojure
06:31	mmeix	using map and reduce instead
06:31	justin_smith	it's useful, but I think people get misled by the name about what it would be good for
06:32	TEttinger	for is often a good solution, but it's "for" generating sequences that you usually want to end up changing with map, reduce, filter, etc.
06:33	mmeix	I see - "reduced" is my finding of the day ...
06:33	mmeix	(inc TEttinger)
06:33	lazybot	⇒ 57
06:34	mmeix	(inc justin_smith)
06:34	lazybot	⇒ 259
06:35	TEttinger	gotta inc justin
06:36	mmeix	which I did :-)
06:36	TEttinger	yeah, but it's basically becoming a rule now that technomancy isn't showing up here
06:36	TEttinger	(identity technomancy)
06:36	lazybot	technomancy has karma 163.
06:36	TEttinger	wow
06:36	TEttinger	he used to be King Karma
06:37	justin_smith	(identity amalloy)
06:37	lazybot	amalloy has karma 276.
06:37	TEttinger	I guess he's still garnering good karma, just uh not bot karma
06:38	mmeix	last question:
06:39	mmeix	,(let [m [1 4 2 7 8 5] ] ((juxt min max) m)
06:39	clojurebot	#<RuntimeException java.lang.RuntimeException: EOF while reading>
06:39	mmeix	umpf
06:39	mmeix	;(let [m [1 4 2 7 8 5] ] ((juxt min max) m))
06:39	justin_smith	so close!
06:40	mmeix	,(let [m [1 4 2 7 8 5] ] (apply (juxt min max) m))
06:40	clojurebot	[1 8]
06:40	mmeix	vs.
06:43	mmeix	,(let [m [1 4 2 7 8 5]] ((juxt first last) (sort m)))
06:43	clojurebot	[1 8]
06:43	mmeix	has one of these an advantage?
06:44	TEttinger	yeah
06:44	mmeix	(if this would be needed a lot of times)
06:44	TEttinger	,(let [m ["the" "quick" "brown" "fox"]] ((juxt first last) (sort m)))
06:44	clojurebot	["brown" "the"]
06:44	TEttinger	min and max are number only
06:44	mmeix	ah!
06:45	mmeix	didn't think of that
06:45	TEttinger	so sort will have better behavior if you need to change it to another comparable type
06:45	mmeix	in my case I have only numbers
06:45	justin_smith	we have max-key and min-key
06:45	justin_smith	(doc max-key)
06:45	clojurebot	"([k x] [k x y] [k x y & more]); Returns the x for which (k x), a number, is greatest."
06:46	tvanhens	I'm having some difficulty wrapping my head around how protocols work in the repl. I have a dsl ns that has various records that implement the same protocol in a protocols ns. Then I have another ns called api that checks to see if the records passed into a function satisfy the protocol in the protocols ns but all the inputs are returning false even though when I call type on the inputs they are returning the proper record type which does implement the
06:46	tvanhens	protocol I am checking for. If I manually evaluate the nses in a different order (dsl first then protocols then api) it works as expected.
06:46	justin_smith	,(let [m ["the" "quick" "brown" "fox"]] ((juxt (partial apply max-key count) (partial min-key count)) m))
06:46	clojurebot	["brown" ["the" "quick" "brown" "fox"]]
06:46	justin_smith	oops
06:47	justin_smith	,(let [m ["the" "quick" "brown" "fox"]] ((juxt (partial apply max-key count) (partial apply min-key count)) m))
06:47	clojurebot	["brown" "fox"]
06:47	mmeix	great stuff!
06:51	j-pb	,(let [m ["the" "quick" "brown" "fox"]] (apply (juxt (partial max-key count) (partial min-key count)) m))
06:51	clojurebot	["brown" "fox"]
06:52	mmeix	juxt as the ultimative extractor
06:53	mmeix	(learning Clojure is really fun)
06:53	tvanhens	it appears that for some reason the namespaces are loading in a weird order and the only way I can get around the behavior is to manually evaluate my namespaces in the right order. Whats weirder is that the problem does not occur when I run my program with lein run or run the tests with lein tests
06:54	tvanhens	it appears that the strange protocol behavior only occurs when I am in the repl
06:54	TEttinger	what's amazing is that the code in there is practically all function calls with names, and almost all of those are defined in clojure. nothing like in java or C or C++ with for(int i = 0; i < 10; i++)
06:54	justin_smith	tvanhens: sounds like you are not requiring something you should be?
06:54	j-pb	,(let [m ["the" "quick" "brown" "fox"]] (apply (partial (juxt max-key min-key) count) m))
06:54	clojurebot	["brown" "fox"]
06:55	j-pb	this also works, but at this point my brain stops properly comprehending whu
06:55	justin_smith	j-pb: ahh, much better
06:55	justin_smith	heh
06:55	tvanhens	I think that might be the case justin_smith hard to track it down when the tests are passing
06:55	justin_smith	tvanhens: it's true I am hard to track down when the tests are passing
06:56	justin_smith	(I know that's not what you meant)
06:56	tvanhens	haha :)
06:56	TEttinger	(inc j-pb)
06:56	lazybot	⇒ 1
06:56	TEttinger	that's a nice golf solution, j-pb
06:57	j-pb	TEttinger: got to think about it some more to make sure it's correct though ;)
06:57	tvanhens	yeah its funky cause the system will start with lein run with no problems. What might cause there to be a discrepency between the two? Its almost as if the repl is using a different protocol even though its the same definition
06:57	j-pb	because right now, the transformation seems correct, but not really intuitive :D
06:57	justin_smith	tvanhens: with the repl are you using the same top level namespace that lein run is?
06:57	mmeix	a bit of brain twister, yes
06:57	hyPiRion	psst
06:57	hyPiRion	,(let [m ["the" "quick" "brown" "fox"]] (apply (juxt max-key min-key) count m))
06:57	clojurebot	["brown" "fox"]
06:58	hyPiRion	no need for partial there
06:58	mmeix	wow
06:58	tvanhens	no. I will try doing that with repl options
06:59	tvanhens	actually scratch that... it is loading into the same top level namespace
06:59	justin_smith	another possibility is any classpath differences between your profiles
07:03	tvanhens	interesting ok so if I restart my repl and then try to eval the user ns or the core test ns I get an error that the records do not satisfy the protocol. However, if I reset my system with stuart sierra (wich uses refresh for ns-es) I can eval either of those two ns-es fine
07:04	TEttinger	I have a feeling you mean one of stuart sierra's libraries, not the person who often is in here
07:04	justin_smith	tvanhens: are things being required in the wrong order?
07:05	justin_smith	TEttinger: he has stuartsierra in another room, when he gets the signal he reloads all the namespaces
07:05	j-pb	hyPiRion: haha very nice, actually using the apply that way make it quite abit more intuitive :D
07:05	j-pb	(inc hyPiRion)
07:05	lazybot	⇒ 75
07:05	tvanhens	haha if only
07:06	mmeix	[light bulb] re: juxt "The returned fn takes a variable number of args" - that made my day
07:06	justin_smith	TEttinger: tvanhens also this reminds me I need to make the tests pass on my port of component to cljc so I can share it (it totally works in my dev code so far, using it for a while now)
07:06	mmeix	thanks guys!
07:06	tvanhens	yeah it looks like they are getting required in the wrong order but only in development. The only difference in the classpath is adding a user and a utils ns when in dev... must be related to those
07:06	j-pb	mmeix: yeah, but actually this is what makes them a tad slower :D compared to #(foo %)
07:07	j-pb	not significantly though
07:07	j-pb	speaking of which, am I the only one really missing a #` reader macro? that would combine #() and `[] ?
07:07	tvanhens	justin_smith: that would be great
07:07	mmeix	so readabilty/understandability wins in this case :D
07:09	TEttinger	j-pb, so it is anonymous fn syntax that produces a quoted list?
07:09	TEttinger	err, syntax-quoted
07:10	j-pb	TEttinger: yeah exactly, the ` syntax quote already produces a set of function call to build the described structures, but you can't use it in a #() form because of the immediate function call
07:10	TEttinger	,`'#(+ % %)
07:10	clojurebot	(quote (fn* [p1__25__26__auto__] (clojure.core/+ p1__25__26__auto__ p1__25__26__auto__)))
07:11	TEttinger	,`~'#(+ % %)
07:11	clojurebot	(fn* [p1__51#] (+ p1__51# p1__51#))
07:11	TEttinger	wheeeeeee
07:11	TEttinger	,(`~'#(+ % %) 2)
07:11	clojurebot	#error {\n :cause "clojure.lang.PersistentList cannot be cast to clojure.lang.IFn"\n :via\n [{:type java.lang.ClassCastException\n :message "clojure.lang.PersistentList cannot be cast to clojure.lang.IFn"\n :at [sandbox$eval77 invoke "NO_SOURCE_FILE" 0]}]\n :trace\n [[sandbox$eval77 invoke "NO_SOURCE_FILE" 0]\n [clojure.lang.Compiler eval "Compiler.java" 6792]\n [clojure.lang.Compiler eval "...
07:11	TEttinger	wowza
07:11	justin_smith	,`~`~`~`~'#(constantly nil)
07:11	clojurebot	(fn* [] (constantly nil))
07:12	justin_smith	,`~`~`~`~`~`~`~`~`~`~`~`~`~'#(constantly nil)
07:12	clojurebot	(fn* [] (constantly nil))
07:13	tvanhens	oy this is annoying. Ok so test-refresh works (which is using the dev profile) lein run works (which is using prod). Starting the repl goes ok. But if I try and run the tests in the test ns without restarting the system... it won't work. Or if I try evaling the user ns. Any other ideas? I guess its pretty simple to workaround but not understanding whats going on is eating at me
07:13	TEttinger	,(defmacro whee [anon] `~anon)
07:13	clojurebot	#'sandbox/whee
07:13	TEttinger	,(whee #(+ % %))
07:13	clojurebot	#object[sandbox$eval177$fn__178 0x4ae63a85 "sandbox$eval177$fn__178@4ae63a85"]
07:14	TEttinger	,((whee #(+ % %)) 2)
07:14	clojurebot	4
07:14	TEttinger	woo
07:14	j-pb	hrhr
07:16	j-pb	but yeah, I find myself quite often in a situation where I would like to map over some data and transform each element to some datasructure, a #` would tremendously help with that
07:17	justin_smith	j-pb: I still don't see where syntax quote helps build data structures
07:18	j-pb	justin_smith: when you deal with xml/html trees, variants or maps representing some kind of record it's really usefull
07:19	j-pb	justin_smith: mostly because of its splicing capabilities
07:19	j-pb	justin_smith: ~@x is the inverse operation for & x
07:21	gfredericks	I always thought list* was
07:21	j-pb	TEttinger: ah sorry I think I missunderstood you, it would be a syntax for producing a function that takes args and returns a datastructure with the arguments embedded at some places
07:22	crocket	(slurp cat)
07:22	j-pb	,(macroexpand '`[:foo %1 %2])
07:22	clojurebot	(clojure.core/apply clojure.core/vector (clojure.core/seq (clojure.core/concat (clojure.core/list :foo) (clojure.core/list (quote sandbox/%1)) (clojure.core/list (quote sandbox/%2)))))
07:22	j-pb	,(macroexpand '#(`[:foo %1 %2]))
07:22	clojurebot	(fn* [p1__49# p2__50#] ((clojure.core/apply clojure.core/vector (clojure.core/seq (clojure.core/concat (clojure.core/list :foo) (clojure.core/list (quote p1__49__51__auto__)) (clojure.core/list (quote p2__50__52__auto__)))))))
07:23	j-pb	while #`[:foo %1 %2] would return basicall y #(clojure.core/apply clojure.core/vector (clojure.core/seq ...
07:24	mmeix	( followup question: would something like "(apply (juxt max-key min-key) count ...)" a use case for a transducer? )
07:25	mmeix	(potentially a silly question, I fear ...)
07:25	j-pb	gfredericks: yeah kinda, but that is what syntax quote will just generate, right? manually building the function calls to generate the datastructures is a lot less obvious than syntax quote
07:26	j-pb	mmeix: could you explain further?
07:26	gfredericks	j-pb: yeah if it does what you need I guess you may as well use it
07:26	mmeix	I'm not sure .... sorry .... does (apply (juxt max-key min-key) count m) generate intermediate lists, internally?
07:27	j-pb	mmeix: no
07:27	mmeix	ah, ok, then the question was silly :D
07:29	mmeix	(partial (apply (juxt max-key min-key) count)) could make sense, OTH, maybe ...
07:29	j-pb	mmeix: well the strings will be cast to a sequence, for count probably, and the apply might turn the input vector to a seq as well
07:29	j-pb	would have to be (partial apply (juxt max-key min-key) count)
07:29	mmeix	ok
07:29	mmeix	ja
07:31	mmeix	(inc j-pb)
07:31	lazybot	⇒ 2
07:53	zamaterian	ikitommi_, should I try to implement a pull request for isssue #121 - that moves the validation into a couple of middleware, as described in my comments ?
08:17	crocket	Ruby map's rehash method terrifies me.
08:17	crocket	It leads to all sorts of bugs.
08:17	crocket	Mutation is bad.
08:19	TEttinger	crocket, if rehash terrifies you, you should see another ruby method, vomit-spiders
08:19	tdammers	is that like Haskell's hypothetical unsafeLaunchMissiles?
08:19	TEttinger	hehe
08:21	TEttinger	vomit-spiders is an interesting function in ruby's standard lib. they don't know when the commit was, but it was before 1970 so the exact time is hard to guess. the comments are in aramaic though.
08:23	TEttinger	the author's name also appears to be permanently lost, since anyone who claims to have decrypted the thousands-of-characters-sequence speaks in tongues for a while then never speaks again.
08:23	TEttinger	which is something of a liability to a large software team
08:25	TEttinger	but it hasn't been removed from the standard lib because Matz has implied that to do so would be very bad if "the stars are not yet right, and the sleeping multitudes have not yet awoken from their dreaming complacency and seen the fire and heard The Screams."
08:25	crocket	What is vomit-spiders?
08:26	TEttinger	$google creepypasta
08:26	lazybot	[Creepypasta] http://www.creepypasta.com/
08:26	tbaldridge	~guards
08:26	clojurebot	SEIZE HIM!
08:26	tbaldridge	crocket: do no speak of this again
08:26	crocket	tbaldridge, this?
08:27	crocket	I need a clarification of what 'this' refers to.
08:28	TEttinger	humor
08:30	crocket	Clojure's data abstractions are as soothing as my aftershave.
08:37	crocket	Heisenbugs...
08:46	crocket	In the land of ruby and java, you'll see heisenbugs...
08:54	crocket	,(map inc [1 2 3])
08:54	clojurebot	(2 3 4)
08:54	crocket	,(doc join)
08:54	clojurebot	Gabh mo leithscéal?
08:56	crocket	(clojure.string/join ["s" "e" "x"])
08:56	crocket	,(clojure.string/join ["s" "e" "x"])
08:56	clojurebot	"sex"
09:19	crocket	How would you allocate memory on JVM?
09:19	crocket	Without aggressive GC, I'm not comfortable.
09:28	profil	why is there no multiple bind version of if-let? sorta like how some-> works
09:31	crocket	profil, Did you ever need a multiple bind version of if-let?
09:36	profil	yes, I find it ugly to nest multiple if-lets
09:36	H4ns	i've also wanted that in the past.
09:36	hyPiRion	Nesting if-lets won't give the same functionality as having a multiple-bind if-let
09:36	crocket	profil, Why don't you make one?
09:36	profil	hyPiRion: what do you mean? some-> threads sequentially when the result is not nil
09:36	H4ns	just because you can add general language-level to clojure does not necessarily mean that it is a good idea to do so.
09:36	Empperi	hmm, that sounds more like what "some-let" should be, not multiple binding version of if-let
09:36	profil	I think scheme has what I want, called and-let
09:36	Empperi	"bind these expressions into let constants as long as the previous binding ended up into something else than nil, then execute the body with those constants available"
09:36	Empperi	if I got it right
09:36	crocket	You should be able to write cond-let.
09:36	crocket	cond is what you want.
09:36	profil	Empperi: yes, by using something like (and ~@binds)
09:36	Empperi	pretty easy to do with some macro magic
09:37	hyPiRion	profil: (if-let [a b] (if-let [b c] foo bar) baz) is different from (if-let [a b c d] foo baz)
09:37	profil	crocket: no, I dont care about which one failed
09:37	profil	hyPiRion: there is no (if-let [a b c d] foo baz) ...
09:37	chouser	actually, that's interesting. cond-let and and-let both sound plausible but would have different semantics.
09:38	crocket	profil, What do you want to do?
09:38	chouser	s/actually,//
09:38	hyPiRion	profil: the point is, even if there were, multiple-binding if-let wouldn't be the same as nested if-lets
09:38	Empperi	definitely, but I can see the use case for what I just described above
09:39	hyPiRion	yeah, sure thing
09:42	crocket	profil, Can you give us a paste of a minimal nested if-let form?
09:42	crocket	I may be able to simplify your code.
09:57	crocket	If you don't care about which one failed, you should nest an if form inside a let form.
09:57	crocket	This is simpler.
09:58	H4ns	crocket: it is also not the same thing
09:59	H4ns	crocket: because when if-let allowed multiple bindings, i would expect it to not evaluate bindings further down as soon as an initialization form returned a false value
09:59	hyPiRion	(let [a b c (and a d) e (and c f)] (if f foo bar))
10:00	crocket	We need to see an actual problem case.
10:00	H4ns	beautiful
10:00	chouser	sounds like nested when-let to me
10:00	hyPiRion	if is probably better to use than and actually.
10:00	hyPiRion	gives same result, but might be easier to read? idk
10:01	chouser	ah, you want one else for any falsey. hm.
10:02	profil	I was thinking of something like "(defmacro and-let [bindings then else] (let [tests (take-nth 2 (rest bindings))] `(if (and ~@tests) (let ~bindings ~then) ~else)))"
10:02	chouser	yeah, and you want 'if' instead of 'and'
10:02	Bronsa	if-lets
10:02	H4ns	profil: nice
10:03	crocket	https://gist.github.com/pingles/5150585
10:03	chouser	profil: good sketch, clarifies things. But runs expressions twice.
10:03	profil	yeah, I havent tested it
10:04	crocket	profil, ^^
10:06	chouser	very interesting attempts. Even the last one in the comments there copies the else clause multiple times in the expansion, though only runs it once.
10:06	crocket	Why doesn't clojure already provide a proper let binding for if-let?
10:08	crocket	I mean multiple local bindings should be available in if-let.
10:09	hyPiRion	crocket: I believe it's because it's not evident what the evaluation rules would be. Given (if-let [a b c d] foo bar), should c be evaluated if a is falsey? If so, then it's "inconsistent" with all the other binding forms out there.
10:09	hyPiRion	Er, I meant the opposite
10:10	crocket	"consistent"
10:10	hyPiRion	I meant: If c is not evaluated if a is falsey, then it would be inconsistent with the other binding forms
10:11	chouser	(if (when-let [a b] (when-let [c d] (when-let [e f] ~then))) ~else)
10:11	chouser	is that it?
10:12	crocket	That is ugly
10:12	crocket	difficult to read
10:13	chouser	Well, I appreciate the input. I was asking if the semantics match what is desired.
10:13	crocket	chouser, That's what I had in mind.
10:14	H4ns	chouser: if then returned falsey, else would be evaluated and returned. that's not right.
10:14	chouser	H4ns: ah, great catch.
10:17	chouser	ok, so hyPiRion's solution, but with 'if' instead of 'and' looks best so far
10:19	crocket	nested if-let sounds nasty.
10:19	H4ns	crocket: if it is only in macroexpansion, what would be wrong with it?
10:19	crocket	Is this a deal breaker?
10:20	crocket	H4ns, Can you show me the macro?
10:21	hyPiRion	crocket: https://gist.github.com/pingles/5150585#comment-981238, was it not?
10:21	H4ns	crocket: i have not written it because in my opinion, it is not right to add semantics to the language at that level. i do think, though, that it would be the easiest path towards a correct solution. i understand the argument that it would be inconsistent with other clojure binding forms if if-let did not always bind all variables, so i'm okay with not having it.
10:22	tbaldridge	you aren't really adding semantics, it's adding syntactic sugar.
10:22	H4ns	tbaldridge: same thing to me.
10:23	tbaldridge	I'm just saying, don't be afraid to use the features of LISP. They're there for a reason, and used correctly they can offer great power.
10:23	H4ns	tbaldridge: that kind of stuff always reminds me of "#define BEGIN {" back in the day
10:24	crocket	That duplicates else multiple times.
10:24	H4ns	tbaldridge: well yeah right. and in the end, i always prefer conventional code to sugar-coated
10:24	tbaldridge	suit yourself, but remember, when is a macro implemented in user code (not in the compiler), same with if-let, if-some, and, or, etc.
10:25	tbaldridge	The compiler only implements about 12 special forms, everything else is syntactic sugar.
10:26	H4ns	tbaldridge: that is just implementation detail. i don't care about the implementation. all i want is that if i see a common control flow or branching form, i can look into the language manual to see how it works.
10:27	crocket	I think I'll get back to it later when it becomes a problem.
10:27	tbaldridge	but that's what (doc 'foo) and (source 'foo) are for.
10:28	tbaldridge	I mean, if you don't want to use macros, that's fine, but just realize you'll be coding lisp with one hand tied behind your back.
10:28	H4ns	tbaldridge: i'm using macros all day long, just not to add syntactic sugar for basic language features that i thing should be "better".
10:29	H4ns	tbaldridge: i think you can stop trying to evangelize me. :)
10:29	chouser	this channel has a bad influence on my responsible use of time :-P
10:31	chouser	destructuring forms cause a bit of a problem with hyPiRion's formulation
10:33	hyPiRion	Oh, I've never thought about destructuring binds in if-lets :o
10:34	hyPiRion	,[(if-let [[a b] [nil nil]] 10) (if-let [[a b] nil] 20)]
10:34	clojurebot	[10 nil]
10:34	hyPiRion	Hrm, I'm not sure what I expected for the first one.
10:35	chouser	well, that's how it's always been. I take advantage of that at times
10:35	chouser	else is only for the expr being falsey. Nothing to do with the bound locals.
10:35	hyPiRion	right
10:36	chouser	but for multiple-binding-if-let, you can't feed nil to users destructuring forms without risking an exception
10:36	chouser	...an exception that they may have been trying to guard against by using if-let :-P
10:37	chouser	But you can't wait and do the destructuring just before the ~then because of course they may be using the bound locals along the way
10:38	hyPiRion	I guess (let [g1# b, a g1#, g2# (if g1# d), c g2#] (if g2# then else)) would work
10:38	hyPiRion	but that looks convoluted
10:38	chouser	no, that's what I'm saying won't work
10:39	chouser	if b is nil, c will be fed a nil.
10:39	chouser	If c is a destructuring form that blows up on nil, you'll get an exception instead of the else
10:40	hyPiRion	ooh
10:40	chouser	er, there are destructuring forms that blow up on nil, right?
10:41	chouser	maybe not. There are destructing forms that blow up, but maybe none with nil.
10:41	hyPiRion	I think you can if you expect the form to be of some shape
10:42	hyPiRion	,(let [{foo :foo bar :bar :or {bar (+ foo 10)}} nil] bar)
10:42	clojurebot	#error {\n :cause nil\n :via\n [{:type java.lang.NullPointerException\n :message nil\n :at [clojure.lang.Numbers ops "Numbers.java" 1013]}]\n :trace\n [[clojure.lang.Numbers ops "Numbers.java" 1013]\n [clojure.lang.Numbers add "Numbers.java" 128]\n [clojure.lang.Numbers add "Numbers.java" 3644]\n [sandbox$eval54 invoke "NO_SOURCE_FILE" 0]\n [clojure.lang.Compiler eval "Compiler.java" 6792]...
10:42	hyPiRion	,(let [{foo :foo bar :bar :or {bar (+ foo 10)}} {:foo 10}] bar)
10:42	clojurebot	20
10:42	chouser	ah, :or ... excellent
10:43	hyPiRion	Heh, macros are hard to get right.
10:43	chouser	trying to expand the else clause exactly once makes this quite tricky
10:44	chouser	you could wrap it in a function, I suppose. But that loses its tail position in the containing form. sheesh
10:46	chouser	Maybe mutating a local flag is the best way. Huh.
10:57	phillord	I'm just trying nightcode out and it seems to be sending my system load through the roof...anyone else had the same experience
11:01	gfredericks	I wrote a basic test.check property testing carmine message queues and immediately ran into a connection pooling quasi-bug https://github.com/ptaoussanis/carmine/issues/135
11:01	gfredericks	(inc test.check)
11:01	lazybot	⇒ 1
12:07	mikerod	I'm struggling to remember what puredanger blog is now
12:07	mikerod	something like "inside a clj developer" - my google searching is failing
12:10	mikerod	http://insideclojure.org/
12:10	mikerod	got it
12:15	CookedGryphon	Hey, I want to download zip files in my application from multiple end points, with associated names and version numbers... this sounds a lot like artifact dependency management. Does anyone know if there's a light weight artifact download/cache management client library that I could bundle with my app?
12:18	dfletcher	https://github.com/cemerick/pomegranate CookedGryphon maybe?
12:18	dfletcher	morning all
12:19	alexyakushev	Does anyone have suggestions how to use gen-class in tests?
12:20	tbaldridge	I don't know that you can, gen-class requires AOT compilation, don't think that works with most test suites
12:23	alexyakushev	tbaldridge: That's what I thought. I'm trying to run compile step before testing now, let's see if it works
12:24	mikerod	Does anyone know of a good post anywhere that compares operations on Clojure transients to some mutable Java types - like Arraylist and then even primitive arrays?
12:24	mikerod	I was doing some microbenches locally with criterium and not getting the expected results (transients were faster)
12:24	mikerod	just doing something basic like, conj'ing up a vector
12:25	mikerod	with longs
12:25	tbaldridge	what java collection were you using/
12:25	tbaldridge	?
12:25	tbaldridge	nvm, just read what you said
12:25	mikerod	I tried PersistentVector vs transient PersistentVector vs ArrayList vs Primitive array
12:25	mikerod	I'm thinking I'm just writing something stupid, but I was hoping to find some solid resource online
12:25	mikerod	where someone already gives a good rundown
12:25	tbaldridge	some code would be good
12:26	mikerod	I'll get some up shortly to demo
12:26	tbaldridge	It could just come down to default sizes of things in Java. transient vectors allocate data in chunks of 32. So it might be possible that ArrayList is using something different
12:28	tbaldridge	Also, array lists must copy all contents every time they resize, while vectors allocate in chunks and don't copy old chunks when creating new. ]
12:28	tbaldridge	So there's a lot of things here that could cause what you're seeing
12:48	franklnrs	when using reagent, is it idiomatic to keep the complete app state in a single atom and have event handlers do deeply nested update-ins?
12:50	dnolen	franklnrs: you should probably direct your question to #clojurescript
12:51	franklnrs	ah yes, will do
12:51	dnolen	franklnrs: Reagent supports both dividing up your state into multiple ratoms and an Om style single atom + cursors.
12:51	justin_smith	franklnrs: I don't think you would need "nested update-ins" - one update-in with a deep nesting of keys maybe...
12:52	justin_smith	unless I misunderstand you here
12:52	franklnrs	and things won't be rerendered multiple times when they depend on multiple ratoms?
12:53	franklnrs	justin_smith, you're right, update-in with deep nesting of keys
13:10	mikerod	tbaldridge: thanks for the input
13:10	mikerod	sorry, I had to step away a few. I have https://www.refheap.com/102091
13:10	mikerod	there is a good chance I just did something wrong in the loop-recur examples, but I don't see where the issue would be
13:11	mikerod	I was also surprised peek-pop traversal of the vector wasn't as fast as first-next - but not completely relevant
13:12	tbaldridge	mikerod: they're slow because you're using first/next to access the vector
13:13	tbaldridge	your first two examples are using the .reduce method on the input vector, this will always be much faster, as it doesn't allocate lazy-seq cells.
13:14	tbaldridge	mikerod: your first two examples eventually call this method: https://github.com/clojure/clojure/blob/master/src/jvm/clojure/lang/PersistentVector.java#L328
13:14	tbaldridge	that'll be much faster than first & next
13:15	tbaldridge	So I'd recommend refactoring the ArrayList example to use reduce. Keep the array list in the accumulator, and call .add on it with each item given to you.
13:19	dysfun	when i deploy an uberjar to my server and java -jar, i get an error saying my core class cannot be found. i've just looked inside the jar and there are AOT versions and the clojure source as well. the named main class is correct. any ideas?
13:20	dysfun	it's built with leiningen
13:21	hiredman	dysfun: is the main class specified in the manifest?
13:23	dysfun	yes, Main-Class is correct in the manifest
13:24	hiredman	and what happens if you run java -cp your.jar your.main.Class
13:25	dysfun	"Could not find the main class: my.app. Program will exit"
13:25	hiredman	how sure are you that the class exists in the jar?
13:26	dysfun	zip -Tv \| grep -v warning \| less
13:26	dysfun	er + the jar filename
13:26	hiredman	(zgrep)
13:26	dysfun	ooh, handy
13:26	hiredman	first thing to do is to blow away target or classes for lein to make sure nothing stale is in there
13:27	dysfun	there isn't anything stale because i don't have leiningen on the target machine
13:27	hiredman	dysfun: on the build machine
13:28	dysfun	okay, it'll take a minute to build and push
13:28	hiredman	the class reported in the "could not find the main class" error exactly matches your main class?
13:28	dysfun	okay, now i get "Warning: The Main-Class specified does not exist within the jar. It may not be executable as expected. A gen-class directive may be missing in the namespace which contains the main method.
13:29	hiredman	there you go
13:30	dysfun	right, so i've got :main ^:skip-aot my.app and :profiles {:uberjar {:aot []}}
13:31	dysfun	if i don't disable aot, i get build errors
13:31	dysfun	i think it's to do with running clojure-1.7.0-beta3
13:31	justin_smith	dysfun: my usual approach is to either use clojure.core as my main (supplying my ns as an arg) or make a very tiny namespace that implements the right magic for jsvc, and use require at runtime, plus resolve, to invoke my stuff dynamically after loading
13:31	hiredman	well, like, fix your build
13:32	dysfun	hrm, i could require at runtime, that could work
13:32	justin_smith	that avoids the issues that come with aot
13:32	hiredman	your build just sounds broken, I would wipe as much as possible from your project.clj and get it working from a clean slate
13:32	dysfun	while fixing it all would be lovely, i've already spent ages fiddling with toolchain
13:33	dysfun	i suppose i probably don't need clojure 1.7 any more now i stopped using the latest clojurescript
13:37	mikerod	tbaldridge: I thought so, but I'm not exaclty sure what my alternatives are
13:38	mikerod	tbaldridge: oh ok
13:38	mikerod	I didn't see your second post
13:38	mikerod	I was skeptical of the first/next stuff
13:41	mikerod	tbaldridge: I also tried iterating over an ArrayList.get() instead of a PersistentVector
13:41	mikerod	It still looked like transients win
13:42	tbaldridge	mikerod: the accessing is muddling your results I think. Perhaps just rewrite them all to use a loop with a counter instead of (vec (range ...))
13:42	mikerod	https://www.refheap.com/102093
13:43	mikerod	tbaldridge: good point
13:43	tbaldridge	Then you're not "complecting" the testing of access with creation.
13:43	mikerod	I figured thesse were just sloppy comparisons
13:43	mikerod	threw it together quick to try to gauge when it really matters if you are using a mutable Java collection vs transient vs persistent immutable
13:44	mikerod	Then I started searching around online and didn't find anything too illuminating out there
13:44	dysfun	justin_smith: brilliant, i used a dynamic require and it works great. thanks!
13:44	mikerod	beyond transients outperforming their persistent counterparts - but I wanted to also try again Java mutation
13:44	mikerod	Java-style*
13:47	tbaldridge	mikerod: dnolen has done some tests showing that transients outperform arrays on JS platforms, but no I haven't seen similar benchmarks on the JVM
13:48	tbaldridge	perhaps that's just because collections are much more tunable on the JVM.
13:48	dnolen	tbaldridge: well JS arrays are really analagous ArrayList not fixed dimension arrays
13:49	dnolen	so it's not surprising that transients wins, they don't have to resize as much
13:50	mikerod	dnolen: I have some experiments against Java primitive arrays too
13:50	tbaldridge	right, but on the JVM "faster" would probably depend on your needs and what JVM collections you used
13:50	mikerod	I still keep "winning" with transients
13:50	mikerod	seems a bit impossible to me
13:50	mikerod	so I figure I have something wrong still
13:51	mikerod	I've also tried starting the ArrayList at the correct, final size. speeds it up slightly, but transient still wins
13:51	mikerod	tbaldridge: https://www.refheap.com/102094
13:51	mikerod	I think I'm keeping the pattern of access consistent here
13:55	tbaldridge	some things are different however. The latter one is doing boxed math on the i value
14:28	Bruce_Wayne	I am having trouble implementing re-com in one of my re-frame projects. Does anyone have re-com working?
14:34	Bruce_Wayne	looking to integrate this library:
14:34	Bruce_Wayne	https://github.com/Day8/re-com
14:35	dnolen	Bruce_Wayne: question more likely to be answered in #clojurescript
14:35	Bruce_Wayne	thank you!
15:06	whodidthis	emacs prelude seems cool but does anyone know where to start if im still not getting pairing ) added when typing (, my modes are(?) Clojure Projectile Pre
15:07	justin_smith	whodidthis: paredit is the mode that does that, also things like prelude are best to ditch as early as you can
15:08	justin_smith	because emacs has standard ways to manage libraries and installation, and using some hacked-up preset setup makes actually managing your own install harder, not easier, in the long run
15:10	pbx	justin_smith, i'm glad to hear you say that because i've had a hard time reconciling such setups with my regular but non-leet use of emacs.
15:11	luxbock	I started out using emacs-starter-kit, then I moved only the things I was actually using to my own setup, but now I eventually switched over to using Spacemacs, which is even more monolithic than Prelude is
15:11	stuartsierra	Most pre-built Emacs set-ups I've seen give you too many new things to learn at once.
15:11	luxbock	and I'm a pretty big fan of it
15:11	brainproxy	justin_smith: I have had nothing but success with prelude over several years and zero friction working with the standard mechanisms for libs and installations
15:11	luxbock	stuff breaks sometimes when I upgrade to the newest develop branch, but overall I really like having actively thought out and developed power user UI
15:11	tbaldridge	emacs-starter-kit was rather recently removed. It's now just a list of packages with instructions on how to do it yourself. Big fan of that now
15:11	brainproxy	prelude, ultra highly recommended in my book, but i realize opinions vary on this subject
15:12	stuartsierra	tbaldridge: glad to hear it
15:12	tbaldridge	They did a good job of walking through what each package does, and why you may or may not need it.
15:13	brainproxy	btw, I merge my fork with prelude's master branch almost every day (i.e. if there are changes) and in the several years I've been using it, only twice has that resulted in a problem requiring me to git reset
15:13	brainproxy	which is a testament to bbatsov's care in making sure that prelude is rock-solid
15:13	luxbock	the difference between now and when I was using the starter-kit before is that now that I've mostly wrapped my head around Emacs and can code in elisp then I can usually figure out pretty fast what broke and how when I upgrade
15:15	brainproxy	also, check out smartparens, an alternative to paredit, actively maintained
15:15	whodidthis	maybe ill do starter-kit instead, seems like a good idea
15:16	brainproxy	whodidthis: going back to your original question, it may be that smartparents isn't enabled
15:16	brainproxy	which is what prelude favors over paredit
15:17	brainproxy	did you copy the prelude-modules.el file from prelude/sample into ~/.emacs.d and uncomment the line for 'prelude-clojure?
15:25	whodidthis	sounds pretty crucial actually heh, thanks
15:25	brainproxy	sure thing
15:25	whodidthis	ill try prelude again after testing this starter-kit
15:25	brainproxy	sure
15:35	justin_smith	one of the complexities introduced by prelude is instead of emacs help, you now need prelude help
15:37	brainproxy	could be; I first started with it and Emacs in late 2011, when prelude was just getting its start as well; the newbie experience w/ prelude in 2015 may be different than mine, i will admit that :-)
15:37	brainproxy	I mainly remember spending time with plain old emacs help and fumbling around looking at prelude source ot understand what was giong on
15:37	brainproxy	*to
15:45	sdegutis	i too do not use prelude
15:46	sdegutis	i tried to make that rhyme but i didnt have the time
15:51	brainproxy	i guess my "bigger picture" view would be that a framework or starter kit that tends to hinder one's understanding and personal development of the Emacs environment is ultimately unhelpful; that hasn't been my experience with prelude, but it could affect others that way, i guess; i haven't worked with other kits, so can't really comment on them
15:52	sdegutis	bbl deadline
15:54	brainproxy	a general recommendation would be to study the source of one's kit of choice and understand what it's doing for you; then, move away from it or morph it into an environment that truly serves your needs
16:30	mikerod	is there any sane way to search through google groups along with sort topics by time etc? I search for these topics online and don't get much help. I feel I'm always struggling to try and use google groups to look through the clj stuff and find what I want.
16:30	mikerod	am I just crazy?
16:31	hiredman	nope, google groups kind of suck
16:43	aaelony	hiredman: agree
16:47	mikerod	hiredman: good to know
16:59	mikerod	http://dev.clojure.org/jira/browse/CLJ-1224 was bumped from major to critical recently
16:59	mikerod	I was hoping that also meant, bumped to 1.7 release instead :P
16:59	mikerod	but I think I'm too hopefully
17:00	mikerod	however, critical does sound like a "big deal"
17:03	xemdetia	does jira have blocker like bugzilla
17:03	xemdetia	or does critical already mean escalated to the mooooon
17:12	fredfe	Will slamhound remove unused (:require)'d items?
17:15	mikerod	fredfe: I doubt it
17:15	mikerod	that's a hard problem too
17:15	mikerod	unused requires sounds very difficult to determine to me
17:15	mikerod	which does bother me about Clojure semantics with loading
17:15	fredfe	Funny, I'd think discovering missing items would be a bigger accomplishment lol
17:15	mikerod	:require can cause a namespace to be loaded and compiled for the first time. This processing can have arbitrary environmental side-effects
17:16	mikerod	1) define global vars 2) define protocols 3) extend protocols to types 4) create new Classes dynamically etc
17:17	arohner	mikerod: 5) run arbitrary clojure expressions at top-level
17:17	mikerod	So my point is, how do you know what an "unused" require is? If it was transitively already loaded by another namespace, that may be ok, but then you're relying on implicit dependencies of your own dependencies, which is a bad practice.
17:18	mikerod	arohner: yeah, I was enumerating common ones. yes, it can certainly just do anything in the world of side effects.
17:18	mikerod	this makes :require management tough from my experience
17:18	fredfe	Makes sense
17:18	mikerod	in larger libraries
17:18	mikerod	I often review people's code and see that they do not specify :require's that they should
17:19	mikerod	because it just happens to transitively be compiled for them
17:19	hiredman	:(
17:19	hiredman	people are terrible
17:19	mikerod	Which is unreliable because it can change out from underneath and break your stuff. Typical transitive dependency issues like from Maven.
17:19	arohner	mikerod: I have a habit of only using aliased namespaces, to prevent that
17:20	mikerod	arohner: yes, I like aliasing a LOT
17:20	arohner	(:require [foo.bar :as bar]), then only ever use bar/
17:20	mikerod	I get scared when people use fully-qualified symbols - which obviously should be rare
17:20	mikerod	but also, if you depend on some protocol extensions from another namespace. that can get messy.
17:21	mikerod	I'm not saying all of this is "best practice" or anything though. I just see it come up often enough.
17:21	mikerod	or you make some defrecords somewhere else
17:21	mikerod	then people do an :import [my.other.ns RecType]
17:21	mikerod	but they don't do a :require on [my.other.ns]
17:21	jarjar_prime	hello :)
17:22	mikerod	hello world!
17:22	jarjar_prime	is there a way to set lein deploy to use uberjar instead of the smaller one?
17:24	hiredman	you don't want that
17:25	jarjar_prime	hiredman: I'm using that to drop into artifactory (maven) and then pull that into a dockerfile
17:29	fredfe	Has anyone used Jenkins with clojure? Is this how it works: Job #1 Pull project from remote git and run tests (lein test--how to capture test results?) ---> Job #2 Run `lein ring uberjar` and Publish over SSH. But what is used to keep some jar versions in case I need to perform an arbitrary number of rollbacks?
17:31	hiredman	fredfe: jenkins can archive builds
17:31	hiredman	fredfe: at work we just have jenkins capture the stdout of test runs and of course the pass/fail of the lein test run
17:32	hiredman	we publish built artifacts to s3
17:32	hiredman	the path on s3 as the version, so we have builds are archived on jenkins, but also on s3
18:11	andyf	fredfe: mikerod: Eastwood linter can determine when :use or :require'd namespace is not used within a namespace, modulo some bugs where it might not report correctly.
18:11	andyf	lein eastwood "{:add-linters [:unused-namespaces]}" https://github.com/jonase/eastwood#unused-namespaces
18:14	mikerod	andyf: how can it know that you aren't relying on the :require for load-compile side-effects?
18:14	mikerod	I know that eastwood is powerful in terms of detecting symbol references
18:14	mikerod	given that (I believe) it uses tools.analyzer to get the AST "big picture"
18:16	andyf	mikerod: I'm not sure what kind of examples you have in mind, but it does some magic, and not other magic :)
18:16	andyf	basically if you :require or :use a namespace, but do not reference any Vars def'd in that namespace, you get a warning that the namespace is unused.
18:16	andyf	It can be fooled, I am sure.
18:18	mikerod	andyf: having a :require to get the side effect of extend-protocol, extend-type, extend, etc
18:18	mikerod	that's the most obvious one
18:18	mikerod	I'm guessing that is bad practice, but it has came up quite a bit from what I've seen.
18:19	mikerod	And as long as it can detect references to deftype'ed classes, that would eliminate my biggest other concern.
18:20	mikerod	But don't get me wrong, I think eastwood is a great project. I was just more ranting over how :require can be tied to side-effects and makes it tricky.
18:21	mikerod	I see a lot of people coming from Java that think of it as like :import - but it is a lot different to that. It potentially does a lot of things, import is just sugar
18:24	arohner	crazy idea of the day, I don't suppose it's possible to pass data from one nrepl to another?
18:25	andyf	Clojure is surprisingly mutable in terms of definitions of things and loading code, and I agree that makes some things tricky.
18:25	mikerod	arohner: if it is in a "pure" data form you should be able to copy/paste?
18:25	arohner	mikerod: yeah, but I'm thinking of a lot of data
18:25	mikerod	andyf: yes, that is the part I'm not a huge fan of... Perhaps it is inevitable though.
18:25	mikerod	arohner: pr it to a file
18:25	mikerod	read it from the file from the other process
18:26	andyf	If you treat Eastwood as "sometimes finds bugs I didn't find using other methods, but sometimes doesn't, and sometimes gives false warnings", i.e. like every other lint tool I've seen, then it might help you.
18:26	mikerod	edn, if you don't trust it.
18:26	mikerod	andyf: I think that is a good way to put it. And I think eastwood can reveal a ton of things that are very helpful.
18:27	mikerod	On the topic of mutable environmental stuff, it looked like https://github.com/mikera/kiss
18:27	mikerod	Tried to address this with "Immutable environments " I was very interested to see where that was going
18:28	mikerod	"immutable all the things"
18:31	andyf	mikerod: You can ask mikera to see if anyone has enhanced it since his proposal, but I think the status is something like "you can patch your own local copies of Clojure all you like, subject to the license". Core team probably doesn't consider it anywhere near high priority for including in the standard distribution.
18:35	Drick	http://i.imgur.com/cbOGiI8.jpg
18:39	m1dnight_	Is there any way to make this fail: (if-let [{a :a} {:b 1}] (println "foo") (println "bar"))
18:39	m1dnight_	Id hate to write an if test and only destructure in a nested let
18:39	m1dnight_	(in the acutal use case {:b 1} would be a call to a function)
18:40	m1dnight_	oh no nvm i was confused for a sec, carry on
18:48	mikerod	andyf: yes, I figured. I was just intrigued by the concept.
18:54	reilly3000	anybody know of updates to arcadia since clojure/west?
19:00	Drick	{`}
19:36	jjttjj	i have a list of heavily nested maps containing things of many types. im trying to end up with a human readable list of every type that appears in the thing. I've been trying to use postwalk to just amass keep conjing an atom but think i might be on the wrong track... is there a way to only deal with leaf nodes?
19:39	hiredman	,(doc tree-seq)
19:40	clojurebot	"([branch? children root]); Returns a lazy sequence of the nodes in a tree, via a depth-first walk. branch? must be a fn of one arg that returns true if passed a node that can have children (but may not). children must be a fn of one arg that returns a sequence of the children. Will only be called on nodes for which branch? returns true. Root is the root node of the tree."
19:40	jjttjj	hiredman: perfect, thanks!
20:10	crocket	http://dpaste.com/3KYMW8W
20:11	crocket	How do I consolidate "else2" and "else1" on http://dpaste.com/3KYMW8W ?
20:12	crocket	I want "else1" to be evaluated and returned if the innermost if-let form's binding evaluates to false.
20:12	crocket	Does anyone have any idea?
20:13	justin_smith	(let [a "3" b "4"] (if (and a b) "then" "else1")
20:13	justin_smith	if "4" should not be evaluated if "3" was nil, then that can be handled also
20:14	justin_smith	(let [a "3" b (when a "4")] (if b "then" "else1")
20:14	justin_smith	if a is nil, b will be nil, guaranteed
20:14	crocket	justin_smith, People are not going to write that by hand.
20:15	justin_smith	I write code like that by hand
20:15	crocket	ouch
20:15	justin_smith	you can use cond
20:15	crocket	There is no cond-let.
20:16	justin_smith	sure, the let thing is a convenience, and it's not available for multiple bindings in any useful way
20:16	crocket	I'm looking for something like (if-let [[result1 result2] (map-all not-nil? ["1" nil])] (+ result1 result2))
20:17	justin_smith	doesn't work though
20:17	justin_smith	it isn't there
20:17	crocket	What isn't?
20:17	justin_smith	that version of if-let does not do what you want
20:17	justin_smith	*that usage
20:17	justin_smith	destructuring + if-let = bugs
20:17	amalloy	welllll
20:17	crocket	That's just a wtf.
20:18	justin_smith	,(if-let [[a b] [nil nil]] "OK")
20:18	clojurebot	"OK"
20:18	justin_smith	crocket: that's just how it works
20:18	amalloy	it's a bit more nuanced than that, as i'm sure justin_smith knows. you can destructure with if-let as long as you know what is going on
20:18	crocket	,(if-let [[a b] nil] "ok" "no")
20:18	clojurebot	"no"
20:18	justin_smith	amalloy: right, but what I am saying is that the semantics he wants do not exist in the core language
20:19	amalloy	justin_smith: i'm just taking issue with "destructuring + if-let = bugs"
20:19	crocket	justin_smith, ^^
20:19	justin_smith	sure, yeah, that was overstating it
20:19	amalloy	everything else you're saying i've only glanced at but is probably spot-on
20:19	crocket	,(if-let [[a b] nil] "ok" "no")
20:19	clojurebot	"no"
20:19	justin_smith	yes, I saw that the first time
20:19	justin_smith	but that doesn't do what you want
20:20	crocket	A hypothetical function map-all should return nil if any element evaluates to nil.
20:20	justin_smith	,(if-let [[a b] ()] "OK")
20:20	clojurebot	"OK"
20:20	justin_smith	so even if you remove nil, it still doesn't do what you want
20:20	justin_smith	OK
20:22	crocket	(if-let [[a b] (reduce (fn [vec el] blahblah....) (map identity ["1" nil]))] "ok" "no")
20:22	crocket	Ok, this is becoming complex...
20:22	crocket	I need to write a macro.
20:22	justin_smith	crocket: to me that is much more complex than using when / and
20:24	crocket	Without (when-let), you have to evaluate something again and bind it to a local binding.
20:24	crocket	Thus, it leads to double evaluation.
20:24	justin_smith	crocket: not in the version I proposed
20:24	crocket	justin_smith, Show me your code
20:24	justin_smith	(let [a (f) b (and a (g))] (if b (h))
20:24	justin_smith	no double eval
20:25	crocket	justin_smith, What if you have to do that for 7 bindings?
20:25	justin_smith	and (g) is not invoked if (f) was nil
20:25	crocket	What if you have to do that for 7-8 bindings repeatedly?
20:25	justin_smith	crocket: then a macro that checks the prior at each step
20:25	amalloy	crocket: if you need to bind 7 separate things to distinct local variables your function is probably a bit lacking in purpose anyway
20:26	crocket	amalloy, 'probably' is not enough.
20:26	amalloy	crocket: the language provides you with the tools to do whatever wacky things you want. there's no "not enough" you can say about the core language, unless it makes something important impossible
20:27	crocket	I meant 'probably' didn't convince me.
20:27	justin_smith	,(let [vaues [a b nil]] (if-not (some nil? values) "OK")) ; something like this?
20:27	clojurebot	#error {\n :cause "Unable to resolve symbol: a in this context"\n :via\n [{:type clojure.lang.Compiler$CompilerException\n :message "java.lang.RuntimeException: Unable to resolve symbol: a in this context, compiling:(NO_SOURCE_PATH:0:0)"\n :at [clojure.lang.Compiler analyze "Compiler.java" 6543]}\n {:type java.lang.RuntimeException\n :message "Unable to resolve symbol: a in this context"\n ...
20:27	justin_smith	,(let [vaues [:a :b nil]] (if-not (some nil? values) "OK")) ; something like this, I meant
20:27	clojurebot	#error {\n :cause "Unable to resolve symbol: values in this context"\n :via\n [{:type clojure.lang.Compiler$CompilerException\n :message "java.lang.RuntimeException: Unable to resolve symbol: values in this context, compiling:(NO_SOURCE_PATH:0:0)"\n :at [clojure.lang.Compiler analyze "Compiler.java" 6543]}\n {:type java.lang.RuntimeException\n :message "Unable to resolve symbol: values in t...
20:28	justin_smith	,(let [values [:a :b nil]] (if-not (some nil? values) "OK")) ; should have tested it first
20:28	clojurebot	nil
20:30	crocket	,(if-let [will-you-dance-with-me nil] "ok" nil)
20:30	clojurebot	nil
20:30	crocket	,(doc if-not)
20:30	clojurebot	"([test then] [test then else]); Evaluates test. If logical false, evaluates and returns then expr, otherwise else expr, if supplied, else nil."
20:31	crocket	justin_smith, That ends up evaluating every binding.
20:31	crocket	I wonder if a lazy sequence could be used for preventing evaluation.
20:32	justin_smith	as long as you watch out for chunking
20:32	crocket	ouch
20:32	crocket	chunks of 32 items
20:32	justin_smith	but, eg lists are not chunked
20:32	justin_smith	so you could use a list of functions
20:32	justin_smith	but a reduce might make more sense unless you have another reason to want laziness
20:33	justin_smith	with a reduced case if any return nil
20:34	justin_smith	(reduce (fn [results f] (if-let [r (f)] (conj results r) (reduced nil))) [] [f g h ...])
20:34	crocket	justin_smith, That's very hard to read.
20:34	crocket	Can you use dpaste.com ?
20:34	justin_smith	one moment
20:35	justin_smith	https://www.refheap.com/102103
20:37	crocket	I never knew about reduced.
20:37	justin_smith	it makes reduce at least twice as useful I think
20:38	crocket	Does reduced terminate reduce right away?
20:38	justin_smith	yes
20:38	crocket	Or, does reduce consume a sequence until the end?
20:38	justin_smith	,(reduce (fn [a n] (if (> n 10) a (+ n a)) 0 (range))
20:38	clojurebot	#<RuntimeException java.lang.RuntimeException: EOF while reading>
20:39	crocket	,(doc range)
20:39	clojurebot	"([] [end] [start end] [start end step]); Returns a lazy seq of nums from start (inclusive) to end (exclusive), by step, where start defaults to 0, step to 1, and end to infinity. When step is equal to 0, returns an infinite sequence of start. When start is equal to end, returns empty list."
20:40	crocket	,(take 10 (range))
20:40	clojurebot	(0 1 2 3 4 ...)
20:40	justin_smith	,(reduce (fn [a n] (if (> n 10) (reduced a) (+ n a))) 0 (range))
20:40	clojurebot	55
20:40	justin_smith	range returns an indefinite sequence - so (range) won't return for a while if eagerly consumed
20:40	crocket	How does clojure catch that?
20:40	justin_smith	catch which?
20:41	crocket	How does clojure catch an infinite evaluation?
20:41	justin_smith	it generally just lets it happen, but clojurebot has print-level and print-length set up to avoid indefinite printing, which with something lazy, prevents indefinite forcing
20:42	justin_smith	,(reduce + (range))
20:42	clojurebot	eval service is offline
20:42	justin_smith	that's because it timed out, of course
20:43	crocket	I wish clojure caught infinite loops.
21:06	wei	interesting puzzle for you all: I want to walk a nested vector and build up an array of indices. e.g. (indices [1 [1 [1 1]]]) => [[0] [1 0] [1 1 0] [1 1 1]]
21:07	gfredericks	,(defn indices [v] (map-indexed (fn [i x] (if (vector? x) (map #(cons i (indices %)) x) (list i))) v))
21:07	clojurebot	#'sandbox/indices
21:07	gfredericks	,(indices [1 [1 [1 1]]])
21:07	clojurebot	#<IllegalArgumentException java.lang.IllegalArgumentException: Don't know how to create ISeq from: java.lang.Long>
21:08	gfredericks	,(defn indices [v] (map-indexed (fn [i x] (if (vector? x) (map #(cons i %) (indices x)) (list i))) v))
21:08	clojurebot	#'sandbox/indices
21:08	gfredericks	,(indices [1 [1 [1 1]]])
21:08	clojurebot	((0) ((1 0) (1 (1 0) (1 1))))
21:08	gfredericks	,(defn indices [v] (apply concat (map-indexed (fn [i x] (if (vector? x) (map #(cons i %) (indices x)) (list i))) v)))
21:08	clojurebot	#'sandbox/indices
21:08	gfredericks	,(indices [1 [1 [1 1]]])
21:08	clojurebot	#<IllegalArgumentException java.lang.IllegalArgumentException: Don't know how to create ISeq from: java.lang.Long>
21:08	gfredericks	poopsiedoodle
21:09	gfredericks	,(defn indices [v] (apply concat (map-indexed (fn [i x] (if (vector? x) (map #(cons i %) (indices x)) [[i]])) v)))
21:09	clojurebot	#'sandbox/indices
21:09	gfredericks	poopsiedoodle
21:09	gfredericks	whoops false poopsiedoodle, meant to scrollback farther
21:09	gfredericks	,(indices [1 [1 [1 1]]])
21:09	clojurebot	([0] (1 0) (1 1 0) (1 1 1))
21:10	gfredericks	phew okay there we go
21:10	gfredericks	wei: ^
21:12	wei	nice!!
21:13	wei	(inc gfredericks)
21:13	lazybot	⇒ 139
21:14	gfredericks	hoo ray a prime
21:16	wei	wish there was a mapv-indexed
21:31	crocket	http://dpaste.com/36F19FE generates an error.
21:31	crocket	How can I fix it?
21:50	crocket	How do I make a macro call itself safely?
21:57	crocket	I created the first working prototype of if-let-all. http://dpaste.com/0S2VYM5
21:57	crocket	Yay
22:00	crocket	Can anyone evaluate if-let-all?
22:02	gfredericks	crocket: I found a bug
22:02	crocket	What is it?
22:02	gfredericks	(if-let-all [x (seq ())] :true-case :false-case)
22:02	crocket	Why is it a bug?
22:02	gfredericks	,(if-let [x (seq ())] :true-case :false-case)
22:03	clojurebot	:false-case
22:03	crocket	oops
22:03	gfredericks	this is a common macro pitfall
22:03	gfredericks	you're preforming your logic on the forms at compile-time
22:04	gfredericks	(coll-or-nil only runs once when you're compiling the macro call)
22:07	crocket	hmm...
22:07	crocket	I think coll-or-nil should evaluate...
22:08	crocket	gfredericks, How about http://dpaste.com/3B45AFB ?
22:08	crocket	(eval f) fixes the bug.
22:08	gfredericks	and that's the next pitfall :)
22:08	crocket	What is it?
22:08	gfredericks	using eval to fix the first pitfall
22:08	gfredericks	here's the next bug
22:09	gfredericks	(let [a ()] (if-let-all [x (seq a)] :true-case :false-case))
22:09	crocket	,(let [a ()] (if-let [x (seq a)] :true-case :false-case))
22:09	clojurebot	:false-case
22:10	hasket	What are people's opinion on haskell vs clojure for web dev
22:10	hasket	(backend)
22:10	crocket	gfredericks, Do you know a solution?
22:10	crocket	hasket, Why don't you try them?
22:11	crocket	For web development, both languages are far superior to ruby, java, and python.
22:11	gfredericks	crocket: you need to be doing the logic at runtime, not compile time; to do that you need to emit code that does the logic
22:11	gfredericks	crocket: I'd play with macroexpand-1
22:11	gfredericks	that might give more insight into where things aren't working
22:12	hasket	I know Haskell quite well. I'm just curious as to what clojure has to offer (I know it's an amazing language and I've played around with it a bit, but not extensively).
22:12	crocket	macroexpand-1 doesn't help me with (let [a ()] (if-let-all [x (seq a)] :true-case :false-case))
22:12	crocket	hasket, One word, ClojureScript.
22:12	crocket	Clojure & ClojureScript
22:12	gfredericks	crocket: you can macroexpand just the if-let-all part
22:13	hasket	crocket, yeah I've tried GHCJS and it's a pain in the butt to install and keep track of dependencies
22:13	hasket	lein seems to work much better than cabal
22:14	hasket	But I'm in love with Haskell's type system is the issue. Does clojure provide any kind of type safety? Or some assurance of safety?
22:14	crocket	hasket, You can use PureScript.
22:14	crocket	hasket, clojure has different ways of ensuring interface integrity than haskell....
22:15	skeuomorf	hasket: https://github.com/clojure/core.typed
22:15	crocket	That being said, haskell is better at checking compile time errors.
22:16	hasket	crocket, yeah that's what it seems like, but I'm fascinated by the language also. I love functional programming. One of my favorite things about haskell is that you can write out the types, then if you don't know the type of something should be in your code, you can leave a hole and haskell will figure out relevant types in scope and tell you what type the hole has. What drew you to clojure? I love the talk "simple made easy" which brought me
22:16	hasket	here :)
22:17	crocket	hasket, It's simple.
22:17	crocket	It's concise.
22:18	hasket	Cool, I'm gonna learn it. I love learning new languages anyways so it's not even necessarily about trying to do anything with it rather than the beauty of the language itself (at least for me). Clojure looks like an elegant language
22:19	hasket	And compiling with ghc and cabal in haskell can be a pain in the butt
22:22	crocket	gfredericks, How do you make if-let-all work?
22:22	crocket	It seems I can't evaluate values in if-let-all.
22:23	crocket	Because values are defined outside the scope.
22:23	gfredericks	crocket: your macro shouldn't be evaluating them
22:23	gfredericks	macros are about rewriting the code
22:23	crocket	gfredericks, Does it mean I have to duplicate the else clause as many times as bindings?
22:23	gfredericks	no
22:23	crocket	The use of (if-let) leads to multiple instances of the same else clause.
22:24	gfredericks	but you have coll-or-nil
22:24	gfredericks	so you can write this with only one if-let
22:24	crocket	????
22:25	crocket	gfredericks, I thought about nesting if-let.
22:25	crocket	If you nest if-let forms, you'll get multiple else clauses.
22:26	gfredericks	(if-let [[a b c] (coll-or-nill [x y z])] true-case false-case)
22:26	gfredericks	^ you want to write it that way, right?
22:26	crocket	Yes, I did
22:26	gfredericks	so your macro needs to emit code that looks like that
22:26	gfredericks	the macro does not need to call coll-or-nil itself
22:26	crocket	ok
22:27	gfredericks	in your original code it does, because of the unquoting
22:27	gfredericks	~(coll-or-nil values)
22:27	clojurebot	I don't understand.
22:27	crocket	good
22:27	crocket	gfredericks, Does it mean I have to expose coll-or-nil?
22:27	gfredericks	you mean make it not-private?
22:27	crocket	Yes
22:28	crocket	I wanted to make it private.
22:28	crocket	with defn-
22:28	gfredericks	you cannot do that easily
22:28	crocket	I should probably inline coll-or-nil in if-let-all.
22:29	gfredericks	btw if you're going to be using this for serious stuff you might want to think about the fact that your current approach doesn't short-circuit -- it will evaluate all of the "values" no matter which ones are nil
22:29	gfredericks	you also can't use previous values in the later expressions
22:33	gfredericks	crocket: http://www.infoq.com/presentations/macros-clojure-west-2013
22:37	crocket	gfredericks, Does anyone have a better version of if-let-all?
22:39	gfredericks	prismatic/plumbing and flatland/useful are a couple places to check
22:39	gfredericks	I don't often find myself wanting it so I'm not sure
22:42	gfredericks	if I had to write it I'd probably use a function or a sentinel to avoid the repeated else clause problem
22:42	tstout	What are the scope rules of a namespace? For example, can a single file define multiple namespaces? Can multiple files contribute to the same namespace?
22:42	gfredericks	(and so still use nested if-lets)
22:42	gfredericks	tstout: there aren't rules about that, only conventions
22:42	gfredericks	tstout: one-to-one is the convention, and there are probably a lot of tools that assume it
23:03	crocket	By the way, when-let doesn't have else clause problem.
23:07	gfredericks	when-let doesn't have an else at all
23:08	figoe	Something weird
23:08	figoe	user=> (into {} (list (vector :a 3))) => {:a 3}
23:08	figoe	user=> (into {} (list (list :a 3))) => ClassCastException clojure.lang.Keyword cannot be cast to java.util.Map$Entry clojure.lang.ATransientMap.conj (ATransientMap.java:44)
23:09	figoe	Any ideas? :)
23:09	gfredericks	figoe: it's a little weird but that's how it works
23:10	gfredericks	pairs for maps have to be vectors
23:10	figoe	Yes, just got bitten by ... heh
23:10	figoe	Guess I gotta do a walk to convert the nested structure to vector or some way
23:11	crocket	gfredericks, When do you use if you want something like if-let-all?
23:14	crocket	When -> What
23:16	gfredericks	crocket: I think I rarely need more than two clauses and so I just tolerate a bit of repetition
23:16	mbuf	in the "Language of the System" talk, it was mentioned that Clojure has the notion of system namespace. Are there any examples to illustrate this?
23:17	andyf	tstout: I'm a little late in answering, but Clojure's require and use determine the source file name to read based upon the namespace name, and check that the namespace has been defined after loading the file. You could define additional namespaces in that same file with other namespace names, but you could not require or use those namespaces successfully from that file.
23:17	gfredericks	mbuf: I can't remember him saying that nor can guess what it means; any further context?
23:17	mbuf	gfredericks, like the use of namespaces in datomic with zookeeper and riak
23:18	gfredericks	mbuf: still nothing, sorry :/
23:18	crocket	I guess people haven't needed to use a lot of bindings in if-let.
23:18	gfredericks	crocket: I'll write one up in a minute
23:19	andyf	crocket: A multiple-binding if-let has been asked about multiple times over the last few years on the Clojure Google group. Different people have written different variants of it as macros.
23:22	ToBeReplaced	seems like too much control-flow to put into the language itself... i think i like that you need to define your own so that you have to decide the semantics you want
23:23	ToBeReplaced	and the "if all of these bindings are non-nil then do this else that" version is very easy to write and a good exercise if you haven't written a binding macro before
23:23	mbuf	gfredericks, https://www.youtube.com/watch?v=ROor6_NGIWU 36:00 - 37:30
23:26	gfredericks	mbuf: I'm can't listen to noise atm, sorry
23:27	mbuf	gfredericks, okay
23:27	cfleming	gfredericks: I'm going to tell Rich you said that
23:28	gfredericks	cfleming: no no! don't tell him! oh god
23:28	gfredericks	I didn't mean that kind of noise
23:28	gfredericks	oh no
23:28	cfleming	That was an even better reaction than I was hoping for
23:29	gfredericks	now he's never going to accept my patch for CLJ-1237
23:30	cfleming	That does look like it would have been difficult to debug
23:30	gfredericks	and then it happened to my teammate a year later!
23:41	gfredericks	crocket: give this a try https://www.refheap.com/102107
23:42	crocket	Jesus
23:45	crocket	gfredericks, Is it better to call recur instead of self in self?
23:45	gfredericks	crocket: it's impossible
23:45	gfredericks	it's not a tail call
23:45	crocket	impossible?
23:46	gfredericks	if you try it you'll get a compile error
23:46	crocket	I don't know what self does.
23:46	gfredericks	that's just a name I gave the function
23:47	gfredericks	or you mean what that function does
23:47	gfredericks	it sets up (if-let [a x] (if-let [b y] (if-let [c z] [a b c])))
23:47	gfredericks	which gives you short-circuiting and visibility of previous results
23:48	crocket	What is short-circuiting?
23:49	gfredericks	if x is falsy it won't evaluate y or z
23:53	crocket	gfredericks, (if-let-all [a 2 b 2] "ok" no") is translated to something like (let [temp [a b]] (if temp (let [[a b] temp] "ok") "no"))
23:54	gfredericks	crocket: that approach doesn't give you short-circuiting
23:54	crocket	Whut
23:54	crocket	gfredericks, I used https://www.refheap.com/102107
23:58	gfredericks	when I expand it I get (if-let [[a b] (if-let [a 2] (if-let [b 2] [a b]))] "ok" "no")
23:58	gfredericks	which is short-circuiting
23:59	gfredericks	you can try (if-let-all [a (do (println "a") nil) b (do (println "b") 2)] "ok" "no") to test out short-circuiting properties