#clojure – 2015-10-01

2015-10-01

00:11	justin_smith	lein do clean, check, eastwood, test, repl
00:48	tmtwd	in cljs, why do we do put! instead of >! ?
00:52	wmealing	tmtwd: i assumed i'd have seen it here https://github.com/clojure/clojurescript/wiki/Differences-from-Clojure
00:53	wmealing	but its not mentioned
00:53	wmealing	and its really hard to google those characaters
00:55	wmealing	may just not be implemented.
00:59	seancorfield	tmtwd: put! and >! do different things...
01:01	amalloy	seancorfield: would it be wrong to say that they do the same thing (or similar things), but in a different context?
01:02	wmealing	characters, man i need a break.
01:03	seancorfield	amalloy: well, they can also take different arguments :)
01:03	rhg135	Technically, >! tells the state machine to pause then resume on successful put
01:04	rhg135	The symbol
01:04	seancorfield	It's been a while since I've worked with core.async but as I recall >! is blocking and needs to be in a thread or a go block, whereas put! is async on its own.
01:05	seancorfield	amalloy: is that a correct summary?
01:06	amalloy	"blocking" is the wrong word. it has to be in a go block because it parks
01:06	rhg135	put! Just puts stuff on a channel, and calls a callback when done iirc
01:07	seancorfield	amalloy: yes, true, that was sloppy wording :)
01:07	amalloy	"async on its own" i'm not sure what you mean, but i'm also not really sure how put! behaves so you are probably right
01:08	amalloy	the thing i know about put! is that it's the most primitive putting operation supported by the platform, which has different semantics in jvm vs js
01:23	elvis4526	Anyone has a good tutorial/explanations for monads? I've read all the interesting stuff that I found the first 1-2 pages on Google :p
02:23	aztak	morning all!
02:29	aztak	anyone want to have a look at some newbie code and let me know what can be improved? https://gist.github.com/metamorph/bdb90be62e9d242eebf3
02:35	sveri	aztak, I wonder, why would you want to have an extra entity for a removed node?
02:36	sveri	s/entity/record
02:55	sm0ke	is there a way to change tools.logging root log level on repl?
03:05	aztak	sveri: perhaps that's a bit too much?
03:06	sveri	aztak, depends on the need, but why would I want to keep a node that's removed from a tree (I am not saying this is invalid, just curious for the usecase)
03:06	aztak	sveri: the idea was to model each possible 'state' as a separate record. The Node record could be created with a flag indicating if it was a 'deleted' node or not, sure.
03:06	sveri	aztak, if it's deleted, remove it from the tree
03:07	aztak	sveri: It's a binary tree, so you still need to be able to find its leaf nodes that are not deleted.
03:07	aztak	sveri: In that case you would need to rebalance the tree (which could be done, of course).
03:07	sveri	AFAIR trees will have to be rebalanced after removal of node
03:07	aztak	yeah, that's it :)
03:08	sveri	I mean, there might always be cases where it is useful to mark a node as "removed" and leave it in the tree
03:08	aztak	I agree (and I'm working on a re-balancing function) but in this scope I'd say the code would become more complex if I introduce re-balancing on removal. Maybe :)
03:09	aztak	thanks for the input though :) Any ideas on how to minimize the repetitive code. Each implementation of insert/member? etc. basically follows the same 'pattern'.
03:10	sveri	Well, my first step would be to get rid of the removed node
03:10	aztak	Check if it's "this" - do one thing. Check if it's gt than 'this' then do something else.
03:10	sveri	and then factor the delete / insert methoud out into it's own method
03:10	sveri	and pass in the "action" functions
03:10	aztak	sveri: like a 'template class' functional style?
03:11	sveri	Not sure what a template class is :D
03:11	aztak	hehe
03:11	sveri	Sounds like C#
03:11	sveri	Or some other C :D
03:11	aztak	(defn do-branch [current-value incoming-value on-eql-fn on-lt-fn on-gt-fn] ...) ?
03:12	aztak	(template method might be the correct name.. )
03:12	aztak	https://en.wikipedia.org/wiki/Template_method_pattern -- very OO.
03:12	sveri	yea, like that
03:13	sveri	and see what it looks like
03:13	aztak	I'll give it a spin this evening :) Thanks for taking time looking at the code!
03:14	sveri	Yea, np, and dont take my words to serious, I just like to poke at things and see if I like it better afterwards. Dont have that much clojure experience myself ;-)
04:05	marshzor	I would like to build a ring request with a html Date header, is there a preferred way of doing this in clojure?
04:11	mavbozo	marshzor, you can use ring-mock https://github.com/ring-clojure/ring-mock to build the request
04:12	mavbozo	and then use ring.util.time/format-date to format your date
04:13	marshzor	thanks, I'll give that a try
04:24	marshzor	hmm I guess ring-mock doesn't really help me since the api I'm using just wants a method, uri and headers map. Good to know about though, thanks mavbozo
04:44	lnostdal	anyone tried clojure 1.8 yet? .. i keep getting this weird exception when compiling: https://www.refheap.com/110150
04:50	neoncontrails	I'm sort of unclear on something: what does leiningen proceed to do when invoked from within a subdirectory?
04:50	neoncontrails	(Say, when you call "lein repl")
04:51	neoncontrails	I'm trying to diagnose why I'm getting errors in some directories which should be a-ok
04:51	neoncontrails	But it runs fine elsewhere
04:54	neoncontrails	I reckon it's a dependency issue of some sort, but I'm not familiar with some of the libraries that show up in the stack trace... i.e. plexus
05:09	sveri	neoncontrails, I am not sure, but my guess is, when you invoke lein repl from a folder where you have a project.clj it reads that one and sets up the environment, but from every other folder it just reads the %USER%/.lein/profile.clj and just starts a repl
05:12	neoncontrails	Hmm. That makes sense, because running "lein repl" elsewhere on my server works fine whether there's a project.clj or no
05:14	neoncontrails	But I'm not sure what the problem could be, in that case. The problem dir is just a straight-up git clone of this git repo, which works perfectly on my local setup: https://github.com/bhauman/flappy-bird-demo
05:15	neoncontrails	ls
05:15	neoncontrails	oops sorry. Similar windows :)
05:20	sveri	neoncontrails, how about you pastebin the error?
05:22	neoncontrails	Sure thing. There's errors like it on the web, but those point to Heroku issues that are not an issue in this case. One sec
05:24	neoncontrails	http://pastebin.com/YA97Pi8d
05:26	neoncontrails	I see elsewhere that this can be caused by a conflicting ~/.lein/profiles.clj file, but I don't appear to have one in that dir's ~/.lein folder
05:36	oddcully	neoncontrails: i cloned the repo from gh and tried with the same lein version. works here
05:36	mavbozo	neoncontrails, what is inside subproject.clj ?
05:37	mavbozo	neoncontrails, is it a file inside flappy-bird-demo/ ?
05:37	oddcully	mavbozo: not according to the clone or the "ls" in the refheap
05:37	neoncontrails	Got it. What eventually solved the problem was "apt-get remove leiningen" and manual install to /usr/bin/dir (I'd previously installed it to /bin/, which might my user might not have had access to)
05:38	TEttinger	phew, glad the birds can be flappy
05:38	nXqd	hi guys, I have a bit problem regarding working with clojurescript. When I develop with figwheel, everything works just fine
05:38	oddcully	neoncontrails: that would have been my next question ;)
05:38	nXqd	but when I compile the project for production with lein uberjar. The javascript has error :(
05:40	mavbozo	nXqd, try lein deps :tree and see if there are any confusing dependencies
05:40	oddcully	nXqd: are/where you "Guest52" over in #clojurescript? the problem with .offsetX on nil?
05:40	nXqd	oddcully: ah no. I'm not
05:40	nXqd	mavbozo: I will try
05:40	neoncontrails	oddcully: I run into dumb Unix obstacles like these pretty frequently, but I have yet to find a good overview of how to rock the command line. Any leads?
05:41	oddcully	neoncontrails: `which lein` to find out what you call. never ever install build-tools from your distri unless you know it's always uptodate
05:41	neoncontrails	Occasionally I'll ask someone, 'hey, how'd you get so good at Unix.' I've never met anyone who has an answer to that
05:42	nXqd	mavbozo: it seems to be a giant list of deps, I see some advice regarding putting exclusions. on lein-fighweel
05:42	nXqd	hmm, I don't think it's the solution. Do you have any ideas
05:42	nXqd	I work with the lein reagent template.
05:43	oddcully	nXqd: often the problems arise with different compiler settings
05:43	neoncontrails	is `which lein` an alias of lein --help?
05:43	neoncontrails	The output is the same
05:43	oddcully	nXqd: can you provide the error in a gist/refheap/...
05:44	nXqd	oddcully: yes I will. I'm trying with the :none optimization, maybe I can see some hint from it.
05:44	TEttinger	neoncontrails: odd. which is a command that should list where the lein executable is on the filesystem?
05:44	oddcully	neoncontrails: which tells you, where the binary is located. if you call `which lein` and see /usr/bin/lein, you see, that you use the system one. your own install would rather show up as ~/bin/lein
05:45	nXqd	oddcully: hmm, I have another error which is goog is not defined.
05:45	neoncontrails	Oh, got it. I was treating the quotes too literally
05:45	nXqd	the the overall is : I get the app working with dev optimizations none.
05:45	neoncontrails	"`which lein'"
05:45	TEttinger	heh
05:46	nXqd	when I use uberjar, the app seems to work, but the interaction with javascript doesn't work. I change uberjar compiler's settings to none, then I get goog is not defined
05:46	oddcully	neoncontrails: `which lein` would execute the result. its basically the same as just running lein (if it's in path)
05:46	nXqd	interaction using javascript*
05:48	oddcully	nXqd: i can not comment on uberjars. but goog missing is most likely not having a main defined or no goog required or wrong stuff in your jar (e.g. only the generated.js instead of the whole out dir)
05:48	nXqd	oddcully: thanks for your comment. I think there is something wrong with my code. I just run uberjar on clean reagent template, everything seems to work fine
05:49	oddcully	nXqd: and if you have problems with full optimazations and external libs, then names get mangled
05:49	TEttinger	oddcully: but `which lein' with the straight quote at the end would not
05:49	oddcully	nXqd: the error would be something like "document has no method .XaJ" where XaJ is something that had a nice name before the compiler optimized it
05:49	TEttinger	that's an odd custom to do quotes like that, I think it was related to some clients rendering it as proper curved quotes?
05:50	oddcully	TEttinger: OP wrote it wrong here. if he had the lein help he called `...`
05:50	nXqd	oddcully: yeah, but I don't have that problem. I have this one Use of undeclared Var clojure.set/intersection
05:51	nXqd	I believe that it's correct to use clojure.set in clojurescript.
05:51	TEttinger	it may need to be required first?
05:51	TEttinger	,(clojure.set/intersection #{1 2 3} {1 4 5})
05:51	oddcully	nXqd: maybe figwheel requires it in its underbelly or some plugin
05:52	clojurebot	#<RuntimeException java.lang.RuntimeException: Map literal must contain an even number of forms>
05:52	TEttinger	,(clojure.set/intersection #{1 2 3} #{1 4 5})
05:52	clojurebot	#error {\n :cause "clojure.set"\n :via\n [{:type java.lang.ClassNotFoundException\n :message "clojure.set"\n :at [java.net.URLClassLoader$1 run "URLClassLoader.java" 366]}]\n :trace\n [[java.net.URLClassLoader$1 run "URLClassLoader.java" 366]\n [java.net.URLClassLoader$1 run "URLClassLoader.java" 355]\n [java.security.AccessController doPrivileged "AccessController.java" -2]\n [java.net.URL...
05:52	TEttinger	,(require 'clojure.set)
05:52	clojurebot	nil
05:52	TEttinger	,(clojure.set/intersection #{1 2 3} #{1 4 5})
05:52	clojurebot	#{1}
06:03	mavbozo	i'm using clojure 1.8.0-alpha5 and clojurescript 1.7.122 and I get this error Exception in thread "main" java.lang.VerifyError: (class: cljs/util$last_modified, method: invokeStatic signature: (Ljava/lang/Object;)Ljava/lang/Object;) Can only throw Throwable objects, compiling:(util.cljc:142:1)
06:07	oddcully	lnostdal mentioned the same error earlier
07:10	lnostdal	oddcully, might be related to this: https://groups.google.com/forum/#!topic/clojure/2t120_atPR8
07:12	mavbozo	lnostdal, what a coincidence, about an hour ago i got the similar problem
07:12	mavbozo	Exception in thread "main" java.lang.VerifyError: (class: cljs/util$last_modified, method: invokeStatic signature: (Ljava/lang/Object;)Ljava/lang/Object;) Can only throw Throwable objects, compiling:(util.cljc:142:1)
07:12	mavbozo	this time with clojurescript 1.7.122
07:12	mavbozo	and clojure 1.8.0-alpha5
07:21	puredanger	That's clj-1809
07:22	nXqd	oddcully: it seems the problem is because of the clojure.set function
07:22	puredanger	It's a bug in the new direct linking stuff
07:34	oddcully	nXqd: i tried earlier. the function works when fired in figwheel without require. have you tried requiring it?
07:34	nXqd	no, I just use it directly without requiring
07:34	nXqd	it works well in figwheel
07:34	oddcully	because figwheel requires it and so it works in figwheel
07:35	nXqd	but when I uberjar, the minified version of javascript doesn't work
07:35	oddcully	put it in your require where you use it and it should work also outside of figwheel
07:35	nXqd	ah, i get it
07:35	nXqd	hmm, some how it's a bit trouble some with the repl isn't it :D
07:46	nXqd	oddcully: sometimes, I get really weird problem with the figwheel repl like, when I first use the application, it seems to not work. But after making figwheel hotreload, it works. How can we address this kind of problem quickly ?
07:49	oddcully	nXqd: how do you handle the reload? are you doing your stuff in the on-something-i-forgot-reload hook? iirc this does not get called on initial load but only when figwheel handles the reload
07:50	roelof_	Hello, Is living clojure together with 4clojure and the wonderland katas a good way to learn clojure ?
07:50	nXqd	oddcully: hmm, I don't have any custom reload hook here in my project.
07:51	nXqd	the error when I first used ( in development ) is the exact error I get when I use uberjar version of javascript
07:52	oddcully	the error with the set? i thought that you got fixed with requiring?
07:54	nXqd	oddcully: ah no. other ones
07:54	nXqd	the error with set is fixed. But is it considered an error with the clojure.set
07:54	nXqd	it should be ok if I use directly with namespace, shouldn't it ?
07:54	nXqd	or if we use clojure lib in clojurescript, we have to require first ?
07:56	oddcully	nXqd: this is not like in e.g. java. you have to require
07:58	spacebug_	mpenet: for a uuid in cassandra, is there any reason prefer your uuid (alia, datastax uuid) over the standard java java.util.UUID/randomUUID
07:58	nXqd	oddcully: ah, yes.
08:02	sveri	Hi, lets say I have an arbitrary map {:id 1 :b {:id 2 :children [{:id 4 :foo :bar}...]}} with an :id key that always has a unique value and I want to update a map somewhere inside the map while only knowing the id, but not the path to the map. How would I do that?
08:06	mavbozo	roelof_, i don't know about living clojure or the wonderland katas, but I found doing the first 80-100 4clojure problems helps me familiarize myself with clojure syntax and frequently used clojure.core functions
08:06	roelof_	mavbozo: oke, thanks
08:08	roelof_	mavbozo: you do nt have used any book to learn clojure
08:08	oddcully	sveri: i just play around with specter. transform with a walker works there
08:08	mavbozo	roelof_, and besides syntax and core functions, also clojure's special forms
08:09	sveri	oddcully, funny, I also tried specter, but couldn't make it work
08:09	sveri	Maybe you have a small example please?
08:09	oddcully	sveri: https://www.refheap.com/3b6eed2bb3ab1e74f760c24a9
08:10	mavbozo	roelof_, i feel comfortable reading Clojure Programming
08:10	roelof_	oke, that is a book I know only with no exercises
08:11	oddcully	sveri: lacks the (use ...) sorry
08:11	sveri	oddcully, np, I try it now
08:11	mavbozo	roelof_, i exercised using 4clojure
08:12	roelof_	oke, and when reading. You can start very soon exercising 4clojure ?
08:13	mavbozo	roelof_, i felt comfortable with Clojure Programming because I have a job as a programmer and i felt that book was written for me
08:15	mavbozo	roelof_, yes, I can directly jump to 4clojure because I have previous programming background with language with repl as ruby or python
08:15	sveri	oddcully, great that works, somehow I assumed a simple selector would do it, but walker is exactly what I was missing
08:17	mavbozo	roelof_, and I started learning python and ruby by playing at the repl and they both have similar exercise tools like 4clojure
08:17	roelof_	oke, then for me the same. I have some experience in ruby
08:17	sveri	I have to admit, specter seems really useful
08:21	roelof_	Oke, then I will try that way. The way with the MOOC from the university of Helsinki does not work for me
08:22	mavbozo	roelof_, what is the name of the MOOC?
08:22	opqdonut	http://mooc.fi/courses/2014/clojure/
08:22	opqdonut	I guess
08:37	roelof_	opqdonut yes, that one
08:45	crocket	Has anyone here migrated from haskell land?
08:46	roelof_	mavbozo yes, the one that opqdonut said
08:50	opqdonut	crocket: I use both
08:51	crocket	opqdonut, What is your verdict on those languages?
08:52	opqdonut	both are very nice
08:52	opqdonut	I like haskell more, but clojure is more practical
08:52	opqdonut	both emphasize purity, which I think is very important
08:55	sveri	crocket, you want to hear the opinion of someone who tried three times to get into haskell?
08:55	crocket	opqdonut, That is it?
08:55	crocket	sveri, Do state your opinion
08:55	crocket	I'm not really sure about what I will use clojure for.
08:55	crocket	Clojure can't certainly be used to write MySQL.
08:55	crocket	Maybe, I can.
08:56	crocket	If I can bear clojure's extravagant memory usage,....
08:57	sveri	crocket, My experience is, that the tooling is not comparable to clojure land. there is nothing comparable to leiningen, which makes it hard to start for beginners. (I know, inbetween there is stack, but it still cannot reach leiningen). Also the IDE support is not close clojure (emacs aside, which I don't want to learn). Everytime I tried it I ran into some setup troubles or problems with cabal or some other problems specific to windows
08:57	roelof_	pity. I cloned the offline github for 4clojure and it fails with ava.lang.UnsupportedOperationException: Unknown Collection type when I do lein run -m offline-4clojure.p1
08:57	sveri	I cannot say much about productivity, as I never got that far
08:57	crocket	emacs is ok
08:58	crocket	I use emacs and paredit
08:59	sveri	Even when I tried emacs I ran into a problem which made me have to restart ghci and emacs all the time I wanted to switch the buffer I was evaluating, there even was a known defect for this which had no simple fix available
08:59	crocket	I mean emacs and clojure mix well
08:59	crocket	not haskell
08:59	roelof_	what I missed what a very nice introduction. I found no good beginners haskell books
09:00	sveri	roelof_, Exactly, that's another point, as a beginner it is really hard to get started at all
09:00	crocket	It may be different now
09:00	crocket	Haskell is pretty mature at this point
09:01	roelof_	exactly. the "experts" say begin with CIS194 course where the second assignment is to solve the towers of hanoi recursive
09:01	sveri	The language surely is, but the tooling and editor support is not, from my point of view
09:01	roelof_	but can someone help me with my unknown collection type error
09:02	justin_smith	sveri: there's a common attitude amongst haskell folks that tooling and editor support are symptoms of a shitty language
09:02	justin_smith	"your language is so bad it needs special editor plugins before you can be productive programming in it'
09:02	sveri	justin_smith, hm, I would have to disagree with this. Especially in larger projects tooling and editor stuff will become so important
09:02	crocket	towers of hanoi?
09:02	roelof_	but I have to leave for some 30 min. My daughter school is out now
09:03	justin_smith	sveri: I'm just reporting that this attitude is prevalent, I don't neccessarily agree
09:03	justin_smith	sveri: and this might explain some of the lack of tooling
09:03	crocket	That sounds elitist
09:03	sveri	justin_smith, Yea, understood, it was an argument against that saying, not you :-)
09:03	justin_smith	crocket: haskell, sound elitist? never!
09:03	crocket	It also sounds exclusionary
09:05	sveri	Gradle for instance, needs two lines of configuration to get a working java project with build, jar and test tasks + support for eclipse or intellij with auto generation of IDE files. 6 lines more will get you dependencies included. Leiningen has the same story, it is so easy to get started with leiningens templates
09:05	crocket	Gradle is more complex than leiningen.
09:05	crocket	You need to know some gradle
09:05	sveri	crocket, You can keep it simple as well
09:06	sveri	true
09:06	crocket	I mean you need to know some groovy to handle gradle well
09:06	crocket	It's groovy
09:06	sveri	OTOH that gives you a lot of options
09:06	sveri	But, my point was, it is very easy to get started
09:07	sveri	whereas in haskell, for a beginner, the easiest thing is to go to fpcomplete
09:08	crocket	I believe there are ebooks that you can download.
09:28	marshzor	anyone know a good way to trim whitespace before and after a string? (trim " stuff ") returns "stuff" ?
09:28	justin_smith	,(clojure.string/trim " this stuff \n \t")
09:28	clojurebot	"this stuff"
09:28	marshzor	oh ...haha, right
09:28	marshzor	sorry
09:28	marshzor	ty
09:29	justin_smith	you even had the name :)
09:29	marshzor	I just tried (trim " stuff ") in repl, asked here, then went to google... I think step 2 and 3 need to be reversed :)
09:29	marshzor	I smell a bad habbit forming
09:29	justin_smith	(clojure.repl/apropos "trim")
09:30	justin_smith	,(clojure.repl/apropos "trim")
09:30	clojurebot	(clojure.string/trim clojure.string/trim-newline clojure.string/triml clojure.string/trimr)
09:30	sveri	Hm, in a distributed system and an ideal world the order should not matter :D
09:30	justin_smith	marshzor: apropos helps :)
09:30	justin_smith	sveri: eventual competency
09:32	sveri	justin_smith, hehe, I have to memorize that
09:45	sveri	Jeez, I could cry, I am working for 2 weeks now figuring out a REST API + some objects and tests in JAVA. Just for the fun I took myself 60 minutes now to do the same in clojure. These endless discussions about the object structure and interfaces and abstract classes. Back and forth where it could be so easy.
09:45	sveri	Kind of frustrating if you have the direct comparison - /rant off
09:46	justin_smith	crocket: regarding your comment on another channel about clojurescript output size, are you using a minified output? because it makes a big difference
09:46	roelof_	one last question : Is there a way I could make 4clojure with my own editor ?
09:46	justin_smith	roelof_: there's an emacs mode for loading and testing 4clojure problems
09:47	sveri	roelof_, I always copied it into lighttable and then copied back. Not to much of an overhead, I think
09:48	roelof_	justin_smith: I tried that one on my cloud ide but I saw this error : unknown collection type error
09:48	sveri	roelof_, if you use vimperator for firefox you can also open a real vim instance in textareas from the browser
09:49	roelof_	sveri: oke, I use now nitrious.io cloud enviroment
09:50	crocket	justin_smith, I'm aware of advanced optimization mode.
09:51	sveri	roelof_, looks cool, didn't know that one, however, maybe its a problem in their environment?
09:52	roelof_	I do not know, I downloaded the offline-4clojure github and that is giving me the problems
09:53	sveri	roelof_, For learning clojure I would take lighttable. you have instant feedback on your code, giving you the fastest turnaround you possibly can have
09:54	sveri	Also you dont need the offline repo, like I said, just copy and paste the functions from 4clojure
09:54	roelof_	oke, I have then I think install linux . Im running now Win 10
09:54	sveri	Hm, I am using clojure on W7 for two years now (except for boot) everything works fine. Don't know why it shouldnt work on W10
09:55	roelof_	sveri: oke, is it easy to install clojure and work with clojure on windows
09:56	sveri	roelof_, you have a JDK installed already?
09:56	roelof_	sveri: I do not think so. I have a bare Windows 10
09:57	roelof_	I thought for clojure you need linux or a mac
09:57	wombawomba	Is there any way to mix the (fn [& {a :a b :b :as kwargs}] ...) and the (fn [& {a :a b :b :or {a 1 b 2}}]) syntaxes?
09:57	noncom	roelof_: clojure works under win like a charm!
09:57	sveri	Ok, so the process is like this: 1. Download and install latest JDK, 2. set JAVA_HOME variable in windows, 3. include the java bin folder in the PATH environment variable. 4. install leiningen 5. download and run lighttable
09:57	sveri	roelof_, if you know what you are doing and have a fast connection you are done in 15 minutes
09:58	noncom	wombawomba: what you need these syntaxes for?
09:58	roelof_	sveri: for point 2 and 3 are there any manuals
09:58	sveri	roelof_, http://www.mkyong.com/java/how-to-set-java_home-on-windows-10/
09:58	noncom	wombawomba: destructuring works for the varargs, so not sure, what's your problem aside from the strange {a :a} form instad of {:keys [a]}
09:59	sveri	roelof_, I have not done it on W10, but it should be straight forward too
09:59	justin_smith	,((fn [& {a :a :or {a 10} :as kwargs}] a)) ; wombawomba
09:59	clojurebot	10
09:59	noncom	wow
09:59	justin_smith	,((fn [& {a :a :or {a 10} :as kwargs}] a) :a "I hate kwargs and you should too") ; wombawomba
09:59	clojurebot	"I hate kwargs and you should too"
09:59	roelof_	oke, thanks all
09:59	sveri	roelof_, good luck!
10:00	sveri	roelof_, I am here for 20 more minutes if you have some questions
10:00	roelof_	light table has a repl for itself ??
10:00	tdammers	hah, on the bright side, I have now successfully demonstrated that loop/recur does indeed run in constant memory
10:00	sveri	roelof_, it's inside the editor
10:00	wombawomba	noncom: I want a function that has default arguments, and where I get a binding to all arguments
10:00	roelof_	I have to leave in a few minutes. Daugther has to go to swimming lessons
10:00	tdammers	(fn [blah] (loop [blub blah] (if (empty? blah) nil (recur (rest blah)))))
10:00	tdammers	ouch
10:01	justin_smith	noncom: {a :a} is the base / more general form, {:keys [a]} is a sugar (which is less useful when keys of more than one map match in one destructure)
10:01	noncom	ah, that's what
10:02	wombawomba	,((fn [& {a :a :or {a 10} :as kwargs}] kwargs) :a "asdfg")
10:02	clojurebot	{:a "asdfg"}
10:02	roelof_	Thanks all and have a good evening
10:02	wombawomba	,((fn [& {a :a :or {a 10} :as kwargs}] kwargs))
10:02	clojurebot	nil
10:02	wombawomba	justin_smith: ^ doesn't work
10:04	justin_smith	wombawomba: you supplied no args!
10:04	justin_smith	,((fn [& {a :a :or {a 10} :as kwargs}] kwargs) :an :arg)
10:04	clojurebot	{:an :arg}
10:04	justin_smith	oh, but there was also no a
10:06	justin_smith	wombawomba: so yeah, I guess that doesn't work
10:06	wombawomba	justin_smith: I want kwargs to be set to the default args by default
10:06	justin_smith	,(let [{{:keys [a b]} :c :keys [d e]} {:c {:a 0 :b 1} :d 2 :e 3}] [a b d e]) ; but this does
10:06	clojurebot	[0 1 2 3]
10:06	wombawomba	yeah
10:06	justin_smith	wombawomba: kwargs are terrible
10:06	wombawomba	ha
12:04	bja	does reader eval support special forms?
12:06	justin_smith	,(eval (read-string "(if true :OK)"))
12:06	clojurebot	:OK
12:06	justin_smith	I don't know if that is what you mean by reader eval, but it was a read followed by an eval
12:06	justin_smith	and the special form was supported in that it executed properly
12:08	bja	(binding [read-eval true] (read-string "#=(if true :OK)"))
12:09	bja	which doesn't work afaict (although I'm probably doing something wrong)
12:09	justin_smith	interesting, can't resolve if
12:09	bja	but (+ 1 5) returns a 6
12:09	justin_smith	haha, if you try "when" instead, you get "wrong number of args"
12:09	justin_smith	because it is calling the macro as a function
12:10	justin_smith	bja: https://www.refheap.com/110173
12:11	bja	nice
12:11	justin_smith	so if you called str on that, and called read-string/eval on that...
12:11	justin_smith	lol
12:11	justin_smith	your half way to a very stupid compiler at that point
12:12	bja	hmm
12:14	bja	I think I just need to reconsider what I'm doing. (binding [read-eval true print-dub true] ....) is madness
12:16	bja	print-dup, although printing code arranged as dub-step would be neat
12:18	justin_smith	bja: simple - attach the wires of your tty to a speaker, then print the code to the tty, instant dubstep
12:20	bja	probably don't want to do that in the office though. they already think I perform black magic with parens.
13:18	justin_smith	bja: speaking of black magic, I literally did a (defn foo [x] (fn [y] (fn [] ...))) today
13:19	justin_smith	it was totally called for though, I swear!
13:19	bja	you actually wanted the clojure and not a partial?
13:19	bja	*closure
13:19	justin_smith	bja: the non-partial form would never be used
13:20	bja	fair enough
13:20	bja	thunks ftw
13:20	justin_smith	I mean yeah, partial would construct the same thing, more idiomatically I guess
13:23	bja	whenever I tink the non-partial form will never be used, I want to debug something in a repl in some remote place
13:23	bja	where I don't want to construct an entire system just to investigate something
13:23	bja	(which is why I refactored almost all of my code that was returning functions to be partials awhile back)
13:38	roelof	sveri: are you here to help me with Lighttable ?
13:47	roelof	anyon who is using light table with clojure and who can explain why I see this output #'fourclojure.core/-main instead of hello world on this code : http://lpaste.net/142085
13:48	justin_smith	roelof: that line does not call -main, it defines it
13:48	justin_smith	the return value of defining a function in your namespace is the var that was defined
13:49	justin_smith	roelof: if you added on the next line (-main) you would see the result of calling it
13:49	hiredman	a function only runs when you invoke it
13:49	roelof	justin_smith: oke, so I have to do (main) to see hello world ?
13:49	justin_smith	(-main)
13:49	justin_smith	yes
13:51	roelof	justin_smith: when I do (-main) I see as output nil
13:52	justin_smith	roelof: println returns nil
13:52	justin_smith	try adding "hello" as the last line of the function
13:52	justin_smith	you should see it return "hello"
13:53	roelof	justin_smith: I should ad just "hello" as the last line of -main.
13:54	roelof	oke, that works, so I cannot see the output of println in a repl of light table ?
13:55	wombawomba	So I'm writing a set of integration tests (currently using midje), and I want some way of stating that all tests will eventually (at least within some period of time) pass, i.e. I want to do something like (eventually "30s" (fact (make-some-api-call) => 4)). In other words, I want to repeatedly perform the check, and have the whole thing pass without failures if the check eventually passes. Does anyb
13:55	wombawomba	ody have any suggestions for how to approach this?
13:58	roelof	justin_smith: is there a way I can see the hello world output somewhere in light table ?
14:00	justin_smith	roelof: my first guess would be the terminal where you started light table, if you started from a terminal...
14:00	justin_smith	maybe it has a tab that shows clojure stdout?
14:00	roelof	justin_smith: thanks I will look if there is a console somewhere. I totally new to lighttable
14:01	justin_smith	roelof: "from the view menu, select console" https://www.safaribooksonline.com/blog/2013/09/11/light-table-workflow-for-interactive-clojure-development/
14:03	roelof	Thanks, now I can try to solve the exercises of 4 clojure.
14:05	roelof	Anyony body knows how I can reset 4clojure so I can start all over again
14:06	wombawomba	Actually, I think my question is this: What should I use to test lazy sequences?
14:06	wombawomba	Midje seems to eagerly evaluate everything, so it might not be optimal?
14:07	justin_smith	wombawomba: I just use clojure.test, and a simple property based test (eg (is (= (first l) :foo)))
14:08	blake_	roelof: You could just create a new ID.
14:09	roelof	But I use all my email adresses, so a new id cannot be done
14:11	xemdetia	roelof, do you use gmail? could try the roelof+tryagain@gmail.com trick
14:11	roelof	xemdetia: I do not use gmail , only one hotmail account
14:12	xemdetia	so it sounds like you just need to make a random new account and use that
14:12	xemdetia	it's not painful
14:15	matthavener	you can always use mailinator.com too, or something like that
14:16	roelof	I have made a gmail account so I can start working on the exercises and work with lighttable Thanks all
14:22	roelof	hmm, why is this not good : (= (list :a :b: :c) '(:a :b :c))
14:29	bja	roelof: (not= :b: :b)
14:29	blake_	,(= '(:a :b :c) (list :a :b :c))
14:29	clojurebot	true
14:30	blake_	,(= (list :a :b: :c) '(:a :b :c))
14:30	clojurebot	#<RuntimeException java.lang.RuntimeException: Invalid token: :b:>
14:30	roelof	blake : the repl of lighttable says false. 4 clojure is happy with the answer. Very wierd
14:31	roelof	found it I made a typo :b: instead of :b
14:31	blake_	oh! lol
14:31	roelof	sorry for the noise on this channel
14:32	sveri	roelof, Hi, did you get it running?
14:32	roelof	sveri: yes, right now I solve the first challenges. The first 10 are very simple
14:32	sveri	roelof, awesome
14:33	blake_	Is there a way to access a vector of vectors other then ((vecs 5) 5)? I know about make-2d-array, I'm talking about just this particular structure.
14:34	justin_smith	,(get-in [[[[1]]]] [0 0 0 0])
14:34	clojurebot	1
14:34	justin_smith	blake_: ^
14:35	blake_	justin_smith: I thought so! For some reason, I thought it was (get-in vecs 2 2).
14:36	justin_smith	there should be a <- macro
14:36	justin_smith	with the <- macro, at each step it would call the return value of the previous
14:36	justin_smith	so it would be (<- [[[[1]]]] 0 0 0 0)
14:36	wombawomba	what's the best way to force clojure not to chunk a sequence?
14:37	justin_smith	wombawomba: use doseq or run! if you want side effects, then chunking doesn't matter
14:37	justin_smith	(usually)
14:38	wombawomba	justin_smith: I want to evaluate a sequence of (really slow) sequence calls, returning the first that fulfills a predicate
14:38	blake_	*some restrictions apply
14:39	wombawomba	and I really don't want to evaluate more than I have to (because slow)
14:39	blake_	justin_smith: Oh, that's clever. I wonder how generally useful that would be. Seems symmetrically necessary somehow.
14:39	roelof	sveri: I have done the first 10 exercises , I call it a day
14:40	sveri	roelof, nice, its a good start. Do you like lighttable?
14:40	justin_smith	wombawomba: in that case, there's a gist out there for a dechunk function (I think it was written by chouser)
14:40	roelof	sveri: yes, I helps well when im stuck
14:40	justin_smith	wombawomba: I just bring up run! and doseq because they are not effected by chunking problems, and are often the better choice if you care about chunking
14:41	sveri	roelof, Yea, thats my experience too. Tremendously helpful to see so fast what a function or expression returns
14:41	roelof	Thanks all and have a nice evening
14:41	sveri	roelof, bye
14:45	wombawomba	justin_smith: alright, thanks
15:06	blake_	Is there a performance/memory use to using Java arrays or is to-array and to-array-2d more about interoperability?
15:07	amalloy	blake_: well, what do you think?
15:09	blake_	amalloy: I can't see a memory improvement. I could see a slight speed improvement if it weren't (potentially) ragged.
15:09	amalloy	blake_: compared to what? lists? vectors?
15:09	blake_	Like, byte-array, I can see both.
15:10	justin_smith	blake_: java arrays use less memory, because they have a lot less structure than our immutable stuff
15:10	blake_	Vectors. I think that's the correct analogue, i.e., vectors are as close to what Clojure has as arrays.
15:10	justin_smith	also perf if they are arrays of primitives, because of cache effects
15:11	justin_smith	blake_: java arrays are contiguous in the heap, clojure vectors are not
15:11	blake_	justin_smith: 2d arrays, though?
15:11	blake_	But wait...vectors are not?
15:11	justin_smith	java doesn't have real 2d arrays, so it would depend on which implementation you are using
15:11	blake_	I'm looking at to-array-2d.
15:12	justin_smith	blake_: vectors use a tree structure in order to allow efficient sharing
15:12	blake_	justin_smith: I suppose it would have to.
15:13	justin_smith	oh yeah, to-array-2d is just a ragged array of object
15:13	justin_smith	so it's not the same sort of thing that eg. a fortran programmer would call a 2d array
15:13	blake_	Right.
15:14	blake_	So, wait, what makes a vector a vector? I sort of envisioned it as an...array. Heh. But that can't be. Still it must be different from a list under the covers.
15:15	justin_smith	blake_: hyPiRion wrote some really excellent blog posts about how vectors are implemented
15:15	justin_smith	blake_: http://hypirion.com/musings/understanding-persistent-vector-pt-1
15:15	thearthur	blake_: it's a trei
15:16	blake_	Oh, I looked at that a while ago. Maybe I can understand it now. =P
15:16	justin_smith	thearthur: when you type "trei" do you intend that to be trei, tree, or trie?
15:16	justin_smith	(we have terrible names in the programming world don't we though)
15:17	blake_	So there's going to be some memory disadvantage, and also some speed disadvantage because of the immutability.
15:17	blake_	justin_smith: trieu, we do
15:22	thearthur	justin_smith: I gave up long ago on anyone agreeing on a spelling pronounciation combination for these. i mean the type of tree use in clojure's vectors and maps
15:24	lgas	can anyone point me in the direction of what I'm doing wrong with this macro? Why is ~fields coming up nil? https://www.refheap.com/110182
15:24	blake_	But actually, I think the heart of my question is not really if Java arrays are more efficient but if that's what the various to-array functions is about. Like, I've never used Java arrays in Clojure. I'm all about the immutability.
15:24	justin_smith	,(apply str (shuffle (seq "trie")))
15:24	blake_	er, are about.
15:24	clojurebot	"irte"
15:25	amalloy	justin_smith: a 12% chance of getting an actual word out of that i think
15:25	justin_smith	sounds about right
15:25	justin_smith	*rite
15:25	thearthur	justin_smith: it's official irte is the new name for "exactly the thing that clojure uses"
15:26	thearthur	pronounced "er-tee"
15:26	blake_	Is it a sop? Is it the only way to use certain Java libraries?
15:26	amalloy	blake_: there are a few occasions where clojure programs use arrays instead of something more reasonable, for performance, but mostly it is for working with java programs that demand an array
15:27	blake_	amalloy: Thanks. That makes sense.
15:27	justin_smith	,(let [a "a"] `(~a))
15:27	clojurebot	("a")
15:29	justin_smith	lgas: (:a :b) evaluates to nil
15:29	justin_smith	,(:a :b)
15:29	clojurebot	nil
15:29	justin_smith	lgas: that's what I think is happening
15:29	justin_smith	try (debug {:fields '~fields})
15:30	lgas	ah that was it. thanks, justin_smith.
15:30	justin_smith	you probably don't even need the ~
15:31	justin_smith	(or the ')
15:31	lgas	without the ~ it comes back as {:fields work.temp/fields}
15:31	justin_smith	ahh
15:31	lgas	without either it doesn't compile because it can't find work.temp/fields
15:32	lgas	but '~fields does what I need.
15:55	blake_	If I have a web app that's accessing a Java object, and multiple users of the web app are accessing the same object--let's say it's a calculator with a persistent set of numbers to work on, but users can change the numbers--what happens when two of them try to access it at the same time?
15:56	blake_	Let's say that the operations are atomic: The user makes a request of the calculator, the web app sets all the values at once and returns the result.
15:56	blake_	So impersistent state doesn't matter because each person sets all the values every time.
15:56	blake_	But could it be that they're both changing the underlying Java object safely, but simultaneously? So that the result comes out wrong?
15:57	blake_	Seems like that would be a possible thing.
15:59	blake_	Otherwise, the object would have to be locked and users would have to wait.
15:59	thearthur	blake_: if you can really say the opperations are attomic(as a group rather than individually) then it's safe
16:00	thearthur	if each value is set atomically, though without regard to the others then it's not gona be fun time
16:00	blake_	Well, not atomically in the sense of atoms. Java object. I have to make a call to set each value.
16:01	blake_	Atomically in the sense of: Each call into the web app contains all the information, the calculator is always in a neutral state, the values are always all put in and the results immediately returned.
16:03	blake_	I could lock the object myself, I suppose. That'd be safe. If people start complaining about response time I could...clone the object, I guess. =/
16:06	amalloy	that's pretty much the only thing you can do if you need to perform multiple coordinated updates to a mutable object
16:07	blake_	Yeah, I was coming to that conclusion. I find myself resenting Java's mutability.
17:03	rasmusto	why is it that transducer composition is reversed from normal function composition?
17:05	akkad	rasmusto: example?
17:07	justin_smith	rasmusto: comp is transforming the functions, not the data
17:07	rasmusto	,(sequence (comp (map inc) (map #(* 2 %))) (range 1))
17:07	clojurebot	(2)
17:07	rasmusto	,((comp inc #(* 2 %)) 0)
17:07	clojurebot	1
17:07	justin_smith	rasmusto: (map inc) is a function that can take a transducer, and returns one
17:08	Bronsa	rasmusto: transducers are not "normal" functions, composing transducers builds a transformation stack
17:08	justin_smith	rasmusto: so the comp is happening in order in terms of function production, but reverse in terms of the data flow
17:08	rasmusto	alright, I think that makes sense
17:08	justin_smith	right, what Bronsa said
17:09	rasmusto	it's actually pretty convenient that I can turn (->> (range) (map inc) (map dec)) into (sequence (comp (map inc) (map dec)) (range))
17:10	rasmusto	since threading is inside-out as well
18:59	noncom\|2	does anyone here have experience working with transit?
18:59	noncom\|2	specifically json enc/dec with non-latin chars
19:00	justin_smith	noncom\|2: it handles my utf8 OK, I'm fond of throwing snowmen around
19:01	noncom\|2	heh :)
19:01	noncom\|2	strange thing - on one machine there's no trouble. on another one - there is trouble
19:01	noncom\|2	specifically java.lang.RuntimeException: com.fasterxml.jackson.core.JsonParseException: Invalid UTF-8 middle byte 0xe0
19:01	noncom\|2	google says this error is almost as ancient as jackson
19:03	noncom\|2	solutions aren't really solutions for me
19:03	justin_smith	so someone is creating utf8 that jackson refuses to handle?
19:03	noncom\|2	justin_smith: it's actually me, yes
19:04	amalloy	your non-working computer is probably creating characters using an encoding other than utf-8
19:04	amalloy	eg like latin-1 or some other garbage
19:04	justin_smith	yeah, a linux or mac box will default utf8 for most stuff, windows will not
19:04	amalloy	and then you take those bytes and tell jackson "hey mate here's some utf-8"
19:05	noncom\|2	i create a webform and set :accept-charset "utf-8" then i send this back to clojure server with transit over a ws
19:05	noncom\|2	same webform, same html. both PCs are win-7 (different editions though but it should not matter)
19:06	noncom\|2	chrome browser encoding is set to utf-8...
19:06	noncom\|2	i don't get where it falls out from utf-8...
19:06	noncom\|2	it's all utf-8 over and through
19:06	justin_smith	until it isn't?
19:06	noncom\|2	yeah!
19:07	noncom\|2	could it be that transit somehow encodes it with non-utf-8 on cljs side?
19:07	noncom\|2	also, the eclipse console, when i println what's coming from the ws, shows correct text
19:07	noncom\|2	it's non-latin chars, but it is perfectly there
19:08	noncom\|2	idk even where to start digging :/
19:09	justin_smith	noncom\|2: it could be that your terminal accepts utf8 bytes that jackson does not, a well behaved terminal should not throw errors when random junk gets printed right?
19:10	noncom\|2	right
19:10	noncom\|2	are there various kinds of utf-8?
19:12	noncom\|2	i thought that the whole point of the "U" letter was to leave all that behind...
19:12	noncom\|2	* the u letter in the acronym
19:21	noncom\|2	amalloy: justin_smith: alright, i had to specify "utf-8" in (.getBytes ws-message "utf-8") so that the correct bytes are given to transit
19:21	noncom\|2	i'm still in wonder why it works on one PC but not the other
19:22	amalloy	the other one has a different default character encoding set
19:22	noncom\|2	with explicit encoding it now works ok
19:22	noncom\|2	amalloy: but.. how? how is this possible? it must be something JVM-wide or OS-wide, but this is near crazy
19:22	amalloy	OS
19:24	amalloy	noncom\|2: it would probably not hurt you to do some research on character encodings in general and utf-8 in specific, if you are confused by this issue
19:24	noncom\|2	well, i had lots of play with them in the past, so not a total newb.. i'd say i get amazed each time something like that happens though
19:25	noncom\|2	but i will surely try to find the roots of this one occasion
19:25	noncom\|2	what that could be in windows doing this
19:29	amalloy	http://stackoverflow.com/questions/9312816/java-platforms-default-charset-on-different-platforms
19:33	triss	would core.logic be a good place to store a list of musical facts?
19:33	triss	well not a list
19:33	triss	like midi notes convert to hz
19:34	triss	hz convert to midi notes
19:34	triss	major scale has these degrees
19:34	noncom\|2	triss: it depends
19:34	hiredman	core.logic doesn't have storage
19:34	noncom\|2	triss: on what you gonna do with tose facts
19:35	triss	so I've got a map of paramaters
19:35	noncom\|2	and yes, it does not store anything. you could define rules to define them - i meant that
19:36	noncom\|2	triss: better use midi -> hz map
19:36	triss	so i've got a map of paramaters... some of the values in the map can be derived from over values in the map and vice versa
19:36	noncom\|2	or look into the pink library
19:36	noncom\|2	or minim for java
19:37	hiredman	that sounds sort of like something you might do with core.logic
19:37	triss	I'm not looking for those functions
19:37	triss	got them out of overtone
19:37	noncom\|2	what's your aim, triss?
19:38	triss	I'm wondering how useful something like converso could be: https://github.com/JeremS/Converso/blob/master/src/converso/core.clj
19:38	triss	but for music
19:38	hiredman	core.logic works more or less like: I have some that I know information and some information that I don't know, I have defined some relationships between different parts of the information, please derive the information that I don't know
19:38	justin_smith	so fill in the rest of this fugue...
19:40	hiredman	if that sounds like what you want, then there you go
19:40	triss	I'm gonna have to take the plunge...
19:40	hiredman	for conversion stuff, if you sort of a closed world of conversions, and you know all the information for the conversions, you may as well directly generate all possible conversions
19:40	triss	I'm a few chapters in to reasoned schemer
19:40	triss	but still have no clue how to impliment
19:41	triss	I'll have a proper look over converso...
20:20	rplevy	did prismatic/schema used to have functions related to walking, and were they removed?
20:20	rplevy	if so, what's the story on that, is it now advised to be done differently?
20:57	rplevy	nm figured it out
21:44	irctc	hello?
21:44	clojurebot	BUENOS DING DONG DIDDLY DIOS, fRaUline irctc
21:45	wmealing	yeah, what he said.
21:45	irctc	lol
21:45	irctc	hello world?
21:58	TEttinger	,(println "Hello, World!")
21:59	clojurebot	Hello, World!\n
21:59	TEttinger	,"Hello, World!"
21:59	clojurebot	"Hello, World!"
23:49	cfleming	Does anyone know if Clojars just got a new cert deployed?
23:50	cfleming	I can't connect from JDK6: “Could not generate DH keypair”, which means that the server requires a DH keypair of > 1024 bits, which JDK6 doesn’t support.
23:55	nathanial	I'm running a dev server with lein ring using nohup but for some reason the way I'm doing it the output isn't going to nohup.out. Is there a way with lein ring or in the application code itself I can specify a log file for all output instead of standard out?