#clojure – 2016-05-01

2016-05-01

12:20	jonathanj	hmm, what the heck does this mean in the grand scheme of things: java.lang.ClassNotFoundException: clojure.java.shell, compiling:(documint/pdf.clj:53:10)
12:21	jonathanj	this only seems to happen when trying to build the uberjar
12:22	jonathanj	i'm calling (clojure.java.shell/sh ,,,)
12:22	jonathanj	do i need to (require) it first or something weird?
12:23	justin_smith	jonathanj: there's nothing weird here - no namespace is available that somebody hasn't required
12:23	justin_smith	jonathanj: and best practice is of course to require it in each ns where you use it (even though you could technically use it if anyone has required it if you use the full name)
12:24	jonathanj	okay, i guess that makes sense i just never paid attention when doing stuff like clojure.core/something or clojure.string/something but i guess something probably does require those already
12:25	justin_smith	right, in a bare repl not even clojure.string or clojure.set are available
12:25	justin_smith	though clojure.core is the one exception - without that you couldn't even require :)
12:25	jonathanj	is there a linter (or such) that could have caught this?
12:25	justin_smith	yes, eastwood
12:25	justin_smith	get it? linter eastwood
12:26	justin_smith	haha
12:26	justin_smith	I've tried quite a few, ://github.com/jonase/eastwood
12:26	justin_smith	err, bad paste
12:26	justin_smith	https://github.com/jonase/eastwood
12:29	jonathanj	thanks
12:29	justin_smith	even "lein check" might catch that (but might not)
12:29	jonathanj	yeah, in retrospect it's kind of obvious that this wouldn't have worked but i guess lein or boot must've been requiring it already so it didn't break in development
12:30	justin_smith	lein check just turns on reflection warnings then compiles every clj file
12:30	jonathanj	what's bad about reflection?
12:31	jonathanj	(lein check emits a ton of warnings for me)
12:31	justin_smith	jonathanj: makes code 100-1000x slower
12:31	jonathanj	mmm
12:31	justin_smith	(well, maybe only 10x slower sometimes, but it's pretty bad for perf)
12:32	jonathanj	good to know
12:33	_maddy	how do I get just the keys from a map?
12:33	justin_smith	_maddy: you're gonna laugh
12:33	justin_smith	,(keys {:a 0 :b 1})
12:33	_maddy	no
12:33	clojurebot	(:a :b)
12:34	justin_smith	OK, you don't have to laugh
12:34	_maddy	thanks, seems to do the trick
12:35	kwladyka	_maddy keep always open http://clojure.org/api/cheatsheet - it is really treasure for knowledge
12:35	_maddy	now lets say I have a map {}, I need to "add" stuff to it, which I guess means to make a new one, but then the map-function returns something else, so do I always need to do (into {} ?
12:35	justin_smith	or use a function that knows how to return a hash-map, sure
12:36	justin_smith	(eg. reduce-kv)
12:36	kwladyka	_maddy try to use this cheatsheet, really, in long term condition you will be happy with that. Just read all function in map section
12:37	_maddy	kwladyka: thanks, bookmarked it
12:37	kwladyka	_maddy you will discover many interesting things
12:37	justin_smith	,(reduce-kv (fn [m k v] (assoc m k (inc v))) {} {:a 0 :b 2 :c 42})
12:37	clojurebot	{:a 1, :b 3, :c 43}
12:37	justin_smith	matt_d: for third party libs, there is also specter
12:37	justin_smith	err
12:38	justin_smith	_maddy: ^
12:40	_maddy	justin_smith: I am adding a new key though, not altering the old ones, is that different?
12:40	luma	,(assoc {:foo 1} :bar 2)
12:40	clojurebot	{:foo 1, :bar 2}
12:40	justin_smith	_maddy: shouldn't be - as long as the info to add keys is somewhere in the input
12:41	justin_smith	_maddy: since you mentioned mapping I thought you were traversing the hash-map
12:41	justin_smith	(which is what reduce-kv is designed for)
12:41	_maddy	not traversing really, just adding a key
12:41	justin_smith	oh, then yeah, just assoc is all you need
12:42	justin_smith	assoc is var-args too
12:42	justin_smith	,(assoc {:a 0} :b 1 :c 2)
12:42	clojurebot	{:a 0, :b 1, :c 2}
12:47	kwladyka	is it possible to write in schema https://github.com/plumatic/schema map has to have :id or :code or both?
12:48	kwladyka	or maybe i am using not the right tool?
12:48	justin_smith	kwladyka: you mean it needs one of the two, and can optionally have one of the others?
12:48	kwladyka	i want prepare schema for data tapes and also required data
12:49	kwladyka	justin_smith {:id 1 :code "fsadfasd"} or {:id 1} or {:code "fdsfdsafads"}
12:49	_maddy	the problem is that I have a two-dimensional map, I need to add something to the inner maps (can't really understand how reduce-kv works)
12:49	kwladyka	perhaps i should use bouncer and schema together
12:50	justin_smith	(s/conditional :id {:id Number Keyword s/Any} :code {:code String Keyword s/Any})
12:50	_maddy	I know how normal reduce works
12:51	justin_smith	_maddy: reduce-kv is just like reduce, except it is optimized for hash-maps, and hands you the key and value as separate args
12:51	justin_smith	_maddy: maybe you can just use update-in or assoc-in ?
12:51	justin_smith	also, reduce is a lot more flexible than people take it for at first glance (as is reduce-kv)
12:52	_maddy	yeah, I usually think of reduce as reducing a collection to single value
12:52	justin_smith	_maddy: a hash-map is a single value :)
12:52	_maddy	sure
12:52	justin_smith	thanks to easy to use collections, a reduce can build up any structure you like
12:53	_maddy	but building up stuff feels contradictory to the name
12:53	justin_smith	yeah, I like the function, but the name (which is very historical) can be misleading
12:53	kwladyka	justin_smith the intention is not readable here but it should work
12:54	justin_smith	kwladyka: there could be a more idiomatic way to express it...
12:54	justin_smith	but the semantics are right at least
12:54	justin_smith	or should be close to it
12:54	kwladyka	i guess i will need some variants also, when X is present i also need Y and Z. Always complete. Not sure yet.
12:54	justin_smith	kwladyka: you could us s/conditional and then use functions that determine if a given variant is present
12:55	justin_smith	kwladyka: best option is stop using so many variant things!
12:55	kwladyka	not really sure what will be the end of requirements :) I am trying to write some schema for data like order, client, product, address to be consistent in whole system
12:56	justin_smith	kwladyka: one thing I like about regular schemas is that in the repl you can pprint them to remind yourself what the data here should look like
12:56	kwladyka	justin_smith i read about that, it should be helpful
12:57	kwladyka	anyway did you hear about some ready data schema for things like i describe?
12:57	kwladyka	maybe somebody did this work?
12:57	kwladyka	even in table in english which i can rewrite to clojure
12:57	kwladyka	it is hard work to design right schema
12:57	justin_smith	I have no idea... a library of common off the shelf schemas could be interesting
12:58	justin_smith	kwladyka: recently I did a massive refactor that would likely have been impossible without prismatic/schema - I captured the values the functions were getting from clients, then I wrote the strictest schemas I could that passed all those values, then wrote my new functions against those schemas
12:59	justin_smith	so much easier than trial and error when the data gets complex
12:59	justin_smith	and more accurate as documentation than any comments could be
13:00	kwladyka	schema looks cool, i think it will be very useful tool
13:01	kwladyka	especially for REST API
13:03	justin_smith	kwladyka: you might be interested in ring-swagger for this https://github.com/metosin/ring-swagger
13:03	kwladyka	justin_smith cool thx
13:08	jonathanj	so how do i fix reflection warnings for code that is something like: (defn [reason] (if (instance? Exception reason) a b))?
13:09	alex-weej	is there an os.path.join equivalent in clojure?
13:09	justin_smith	jonathanj: that's a tricky one
13:09	justin_smith	alex-weej: what is os.path.join
13:09	jonathanj	it joins several OS path components together with the OS-specific separator
13:10	alex-weej	and also deals with segments starting with a / so jumping back to the root
13:10	kwladyka	jonathanj http://clojure.wladyka.eu/posts-output/2015-08-24-how-to-improve-algorithm-speed.html#avoid_reflections
13:10	alex-weej	os.path.join(“foo”, “bar”, “/baz”) == “/baz”
13:10	alex-weej	assuming pathsep is /
13:11	_maddy	ok, I am not getting it, lets say I have map of maps: { "A" { :key 1 } }, how do I add new key/value to the inner maps? And by calculating that, I need the key of the inner map
13:11	kwladyka	jonathanj and there you have ready solution https://www.refheap.com/8bff42793e9abbeb9af803b23
13:12	kwladyka	to not throw an exception if you don't have class loaded
13:12	kwladyka	this one is hard one to solve :)
13:14	justin_smith	,(java.nio.file.Paths/get "foo" (into-array ["bar" "baz" "quux"])) ; alex-weej this is ugly, but it works
13:14	clojurebot	#object[sun.nio.fs.UnixPath 0xfe5389 "foo/bar/baz/quux"]
13:15	justin_smith	if you call str on it you get the path as a string
13:15	justin_smith	alex-weej: https://docs.oracle.com/javase/7/docs/api/java/nio/file/Path.html
13:15	jonathanj	kwladyka: that's not what the code does
13:16	alex-weej	is there some project to wrap java APIs in more clojure-friendly terms btw?
13:16	kwladyka	jonathanj ?
13:16	jonathanj	kwladyka: the code does a if the object is an instance of an exception and b if it's not an instance of exception
13:16	alex-weej	would be cool to collect some of the more “obvious” bindings
13:16	justin_smith	alex-weej: there are N+1 projects
13:16	jonathanj	kwladyka: whether the class is loaded or not is not really important, unless i'm missing something
13:16	justin_smith	alex-weej: clojure is a java library, it's all accessible, and sometimes people want to add a friendly layer on top
13:16	kwladyka	jonathanj ok maybe i mentioned about that unnecessary
13:17	kwladyka	jonathanj did you look on http://clojure.wladyka.eu/posts-output/2015-08-24-how-to-improve-algorithm-speed.html#avoid_reflections ?
13:17	alex-weej	justin_smith: sure, i’m just wondering if i can pull-request a library of wrappers for things like java.nio.file
13:17	jonathanj	kwladyka: not yet
13:17	alex-weej	this doesn’t work anyway, user=> (str (java.nio.file.Paths/get "foo" (into-array ["bar" "baz" "/quux"])))
13:17	alex-weej	"foo/bar/baz/quux"
13:18	kwladyka	jonathanj it should explain how to solve your problem
13:19	shiranaihito	,(str (java.nio.file.Paths/get "foo" (into-array ["bar" "baz" "/quux"])))
13:19	clojurebot	"foo/bar/baz/quux"
13:19	shiranaihito	what's wrong with that? :)
13:19	justin_smith	also, that's super easy to wrap in a vararg string function
13:20	bacon198`	alex-weej: a good number of projects are trying to making the java libraries more friendly
13:20	jonathanj	kwladyka: i don't actually understand how it solves my problem
13:20	bacon198`	which is great, because you get tried and tested libraries being wrapped nicely
13:20	jonathanj	kwladyka: the problem is that i cannot provide a type hint to a value that has a dynamic type
13:20	shiranaihito	bacon198` i sure hope they're not wrapping some goddamn commons-turdnuggets from 1998 or something
13:20	alex-weej	In [2]: os.path.join("foo", "bar", "/baz")
13:20	alex-weej	Out[2]: '/baz'
13:21	shiranaihito	ah.. Python :P
13:21	jonathanj	i think i'm going to have to change the calling code to convert Exception so that i don't need the test
13:21	shiranaihito	alex-weej what do you mean with that though? does python just ignore the first two elements? is that what you want?
13:22	TimMc	alex-weej: I believe that reducing over the segments with the File constructor does what you want, if no one has mentioned that...
13:22	justin_smith	TimMc: not with the example he gave
13:23	TimMc	Hmm, lemme find the code of mine that does this...
13:24	TimMc	Ah, yeah, I see I ran into that problem as well.
13:25	TimMc	https://gist.github.com/timmc/de9251eb5343bcc72ef20347ef24026c
13:25	TimMc	Needs cleanup, since I wrote it quite a while ago. :-)
13:25	justin_smith	TimMc: yeah, line 6 should be 3 lines, but it's not super bad
13:26	kwladyka	jonathanj maybe i miss something but what you pasted here doesn't throw reflection wartning
13:26	kwladyka	jonathanj are you sure where is the source of this warning?
13:26	TimMc	justin_smith: I also don't need to capture f2, I can just use it and discard it in the conditional.
13:26	kwladyka	(defn foo [x] (instance? Exception foo)) is really free of this warning
13:27	kwladyka	i mean (defn foo [x] (instance? Exception x))
13:28	justin_smith	kwladyka: I was skeptical so I double checked, you're right
13:28	kwladyka	jonathanj so i pasted you my article to help you find the right place which makes this warnings
13:29	shiranaihito	alex-weej or you can join some strings and give them to File
13:29	shiranaihito	,(str (java.io.File. (clojure.string/join "/" ["foo" "bar" "baz"])))
13:29	clojurebot	"foo/bar/baz"
13:30	kwladyka	justin_smith i checked that too twice :)
13:30	justin_smith	shiranaihito: fails on alex-weej 's example though
13:30	alex-weej	doesn’t work when one of the segments is an absolute path e.g. my example
13:30	shiranaihito	ok
13:30	shiranaihito	,(str (java.io.File. "/foo" (clojure.string/join "/" ["bar" "baz"])))
13:30	clojurebot	"/foo/bar/baz"
13:31	justin_smith	that isn't any better
13:32	shiranaihito	well it does start with an absolute part :P
13:33	shiranaihito	if one of the elements denotes an absolute path, it probably goes in first anyway
13:38	justin_smith	also, platforms are allowed to use separators other than "/"
13:40	TEttinger	J:☃Users☃Justin☃Code☃
13:41	shiranaihito	justin_smith and that means my little snippet was bad? :P
13:41	justin_smith	shiranaihito: it's a second way it doesn't address the initial question
13:42	justin_smith	which explicitly mentioned using the system's native separator
13:42	shiranaihito	chill :)
13:42	kwladyka	shiranaihito i believe i saw some ready solution for that in the past.... maybe
13:43	shiranaihito	,(str (java.io.File. (str java.io.File.separator "foo") (clojure.string/join java.io.File.separator ["bar" "baz"])))
13:43	kwladyka	but it can be my imagination
13:43	clojurebot	#error {\n :cause "java.io.File.separator"\n :via\n [{:type clojure.lang.Compiler$CompilerException\n :message "java.lang.ClassNotFoundException: java.io.File.separator, compiling:(NO_SOURCE_PATH:0:0)"\n :at [clojure.lang.Compiler analyze "Compiler.java" 6688]}\n {:type java.lang.ClassNotFoundException\n :message "java.io.File.separator"\n :at [java.net.URLClassLoader$1 run "URLClassLoade...
13:43	shiranaihito	alright.. something like that anyway :P
13:43	shiranaihito	kwladyka solution for what? the file path stuff?
13:43	justin_smith	,java.io.File/separator
13:43	clojurebot	"/"
13:43	shiranaihito	yeah, just realized
13:44	kwladyka	shiranaihito some library to do that or Java function.... i don't really remember. Some solution to make the right path
13:44	shiranaihito	yeah, it's not that complicated
13:44	shiranaihito	i figured joining strings and then just handing them to File would be "neater"
13:44	shiranaihito	or simpler (etc whatevs) than reducing with Files
13:45	kwladyka	i believe anyway you miss many not obviously things, like for example different systems
13:45	kwladyka	path in the windows for example can looks like c:/foo/bar
13:45	shiranaihito	sure, but that's what further development is for :p
13:45	shiranaihito	we're just swapping snippets to help people
13:50	_maddy	my god, after all this work I have a data structure which looks really cumbersome..
13:54	alex-weej	is there some popular or built in library for running subprocesses and dealing with their events (e.g. stdin/stderr output, process exit) via an event loop or something?
13:56	shiranaihito	alex-weej: Java kind of has support for that
13:56	shiranaihito	look at ProcessBuilder for example
13:56	justin_smith	there's ProcessBuilder and also conch which wraps ProcessBuilder / Process
13:56	shiranaihito	but for whatever it's worth, i couldn't get communicating with subprocesses to work when i tried
13:57	justin_smith	shiranaihito: each Process object has two inputstreams and an outputstream
13:57	shiranaihito	yeah
13:57	shiranaihito	as far as i know, i was using it right.. not 100% sure ofc
13:58	justin_smith	I've done it before, it worked fine
13:58	shiranaihito	but something was wrong when trying to do input/output with processes
13:59	alex-weej	conch looks interesting thanks - wondering if i should try to shoehorn something into core.async
14:00	alex-weej	i want to have a bunch of subprocesses running at any one time and just select on their events
14:04	justin_smith	alex-weej: you could have regular threads that glock on read from the inputStream of the processes
14:05	justin_smith	alex-weej: don't do that in go blocks, go blocks are not for blocking operations
14:05	alex-weej	one per process?
14:05	justin_smith	yeah, and a single go block reading the results they put on the channel
14:05	alex-weej	sounds simple enough - is it actually reasonable straightforward to start threads in clojure?
14:06	kwladyka	alex-weej what exactly do you want to achieve? maybe you want just share state?
14:06	alex-weej	i just want to run a set of subprocesses and then multiplex their events in a loop
14:07	alex-weej	events are like - ready for read on stderr, ready for read on stdout, ready for write on stdin, process terminated with exit code N
14:08	justin_smith	alex-weej: shiranaihito: simple repl example of i/o with a process in the repl (in a real example you would read to a byte-array, not read a byte at a time, of course)
14:08	justin_smith	https://gist.github.com/noisesmith/f2ca73a0a6b0e5d686487c6084196a97
14:08	alex-weej	if this was low level linux i would fork and exec and do some fd sharing, and just epoll the fds without the use of any threads
14:08	justin_smith	alex-weej: the api doesn'
14:08	justin_smith	t expose "ready for" anything, sadly
14:09	justin_smith	which is why I mentioned threads doing blocking reads/writes
14:10	shiranaihito	justin_smith thanks :) i think my main problem was taking stuff from one process and handing it into another, but i just scrapped what i was doing and went with Python instead
14:10	shiranaihito	.. and Python did exactly what i wanted with like a couple of lines of code :)
14:11	justin_smith	shiranaihito: the biggest gotcha is needing to do the .flush method iirc
14:11	shiranaihito	i'm pretty sure i flushed stuff too.. i've used Java for a long time
14:12	justin_smith	the problem with system stuff in java is it is committed to the lowest common denominator, and there are some really low targets it had to hit in the past (Win9x etc.)
14:12	justin_smith	shiranaihito: oh, OK
14:12	justin_smith	shiranaihito: I built a crazy system that piped the contents of a 16 channel sound card to 16 separate programs in clojure - which was amazing and also a pain in the ass
14:12	justin_smith	but it worked!
14:12	shiranaihito	basically i was trying to: start a process, feed it input, wait for it to complete (working on the input), and then hoping to take out whatever it produced.. and hand it off to another process
14:13	justin_smith	shiranaihito: see, the people who wrote the software spec assumed there was a "read one channel of a sound card" api - which of course doesn't exist anywhere
14:13	shiranaihito	wow, sounds hard-core
14:13	justin_smith	I didn't really grok core.async until I completed that project :)
14:13	shiranaihito	:)
14:13	shiranaihito	i haven't even tried using it yet
14:14	jonathanj	can i add a type hint to a parameter inline?
14:14	jonathanj	`(.someMethod obj ^long value)` for example
14:15	justin_smith	alex-weej: a lot of the stuff you are trying to do is easier in pixie, which is still kind of experimental, but it's a clojure implemented using rpython's compiler (but there is no python available at runtime mind you)
14:15	shiranaihito	"inline"?
14:15	justin_smith	jonathanj: yeah, that should work
14:15	kwladyka	jonathanj why not in the definition of function?
14:16	kwladyka	i mean in the parameters
14:16	jonathanj	kwladyka: because it's just a minor intermediate result
14:18	kwladyka	jonathanj i guess more readable it will be when you use ^long somewhere when this result comes, i don't know what you use, let or something
14:22	_maddy	how do I configure cider repl so that I have to use ns in front of functions (I want to have functions of same name in 2 files)
14:23	kwladyka	_maddy just use namespaces when call this functions
14:24	kwladyka	foo/f and bar/f
14:24	hodwik	If I want to send a header param as part of a post with clojure-http, do I just make a map {:headers {:API_KEY
14:24	hodwik	"APIKEY"}}
14:24	hodwik	and send that as part of the post?
14:28	alex-weej	is there a common idiom or builtin for combining let with if? e.g. (let-if [x y] then else) -> (let [x y] (if x then else)) - to avoid repeating x
14:29	ridcully_	hodwik: that's how it works in clj-http. did you mean this or the clojure-http-client lib?
14:30	hodwik	@ridcully sorry, that's what I meant
14:33	jonathanj	the type hints from protocols are disregarded in defrecord implementations?
14:33	kwladyka	alex-weej if-let still you don't try use cheatsheet, just click there ctrl+f in your browser
14:34	hiredman	they don't exist
14:35	hiredman	e.g. you can attach metadata to the parameters in a protocol, but it doesn't do anything
14:35	alex-weej	kwladyka: i see it’s spelled if-let, that makes more sense actually!
14:35	alex-weej	thanks
14:36	hodwik	Could anyone with clj-http experience tell me why this: http://pastebin.com/8nwSeqVA is spitting out:Exception in thread "main" java.lang.ClassCastException: clojure.lang.PersistentArrayMap cannot be cast to [B, compiling:(stfr_bot/core.clj:74:1)
14:36	hodwik	the variables are all def'd before that section
14:38	ridcully_	hodwik: i think it has to be :json there. also i doubt it will deal with the json conversion anyway
14:40	ridcully_	hodwik: something like this: https://github.com/christoph-frick/rest-repl/blob/master/src/rest/public.clj#L56-L59
14:41	TEttinger	[B is that wacky stacktrace-speak for byte array
14:45	justin_smith	,(class (.getBytes "foo"))
14:45	clojurebot	[B
14:46	hodwik	ridcully: Awesome! Thanks so much. I was trying to use Cheshire to encode my json, but just doing it with clj-http was much easier
14:49	_maddy	how do I pass-through variable arguments to another function? I can create optional args with &, but they are set to nil (and sent as nil to the next func, which is a problem)
14:49	justin_smith	_maddy: if you use arity overloading instead of &, then it's much easier to provide defaults
14:50	justin_smith	,((fn foo ([] (foo
14:50	clojurebot	#<RuntimeException java.lang.RuntimeException: EOF while reading>
14:50	justin_smith	err
14:50	justin_smith	,((fn foo ([] (foo "hi")) ([message] message)))
14:50	clojurebot	"hi"
14:51	_maddy	I could use arity overloading, but it looks like then I have to repeat the function body multiple times
14:51	_maddy	which is not nice
14:51	justin_smith	_maddy: no, that's never needed
14:51	justin_smith	_maddy: look at my example, no repitition
14:52	justin_smith	,((fn f ([] (f 2)) ([x] (* x x x)))
14:52	clojurebot	#<RuntimeException java.lang.RuntimeException: EOF while reading>
14:52	_maddy	oh, but the problem is that I don't want to define defaults here, they are defined in the inner function which I am calling
14:52	justin_smith	,((fn f ([] (f 2)) ([x] (* x x x))))
14:52	clojurebot	8
14:52	_maddy	where I already have arity overloading pattern
14:53	_maddy	I think I am too tired, have to continue on another day :)
14:53	_maddy	really liking clojure now that I am slowly starting to understand it
16:05	beaky	i love clojure too
16:23	jonathanj	if i have a protocol method defined like (foo [this ^SomeObj x]) and i have the implementation (on defrecord, for example) like (foo [this ^SomeObj x]) then i get a compile error like: Can't find matching method: foo, leave off hints for auto match.
16:24	jonathanj	if i omit the type hint for the implementation then it compiles but `x` is not type hinted
16:29	TimMc	Could it be that you need to throw more type hints at it? I haven't worked with protocols recently, but I wonder if "this" or the return value need hinting (seems like overkill though).
16:33	amalloy	protocol functions don't support type hinting anyway
16:44	jonathanj	how do i unambiguously import two java classes with the same name?
16:44	clojurebot	excusez-moi
16:47	amalloy	the same way you do it in java: only import one of them, and refer to the other fully-qualified
16:49	jonathanj	i don't recall ever having to do this in java, so i wasn't aware if there was another way
16:49	TimMc	There's another option, which is .importClass...
16:49	jonathanj	C# has some way to alias stuff, iinm
16:51	TimMc	If you don't mind potentially messing up some automated tooling and IDEs, you can do (.importClass ns 'RLN foo.bar.ReallyLongName)
16:51	TimMc	stick that right after your ns block and say two Hail Marys
16:52	jonathanj	haha, i'll just go with the fully qualified option
16:57	TimMc	I've done this once and never had a problem with it, just... you know, fair warning.
17:02	jonathanj	like that guy who puts his hand into the crocodile's mouth and doesn't get bitten, then he calls his friends over to see his neat trik
17:08	TimMc	jonathanj: There are two risks: 1) It might go away (binary .importClass is not used anywhere I can see in 1.7.0), and 2) tools might expect all imports and requires to be parseable from the ns block.
17:08	TimMc	So: Possibly annoying, but it's not like the program will behave incorrectly if it runs at all.
17:24	fikgol	why storm used maven instead of leiningen after 0.9 ?
17:25	TEttinger	fikgol: I might be thinking of a different storm
17:34	TEttinger	fikgol, ah https://github.com/apache/storm/pull/14
17:34	TEttinger	apparently their build process is complex
18:03	vermiculus	i've got an algorithm challenge if anyone fancies a crack at it
18:03	vermiculus	it's a recursive question involving maps
18:06	TEttinger	me crack
18:07	vermiculus	TEttinger: :)
18:07	vermiculus	Say you have a structure like {1 {:parent :root, :slug "lovely"}, 2 {:parent 1, :slug "lovelier"}, 3 {:parent 1, :slug "loveliest"}, 4 {:parent :root, :slug "cool"}}
18:08	vermiculus	Notice that this is pretty much a tree of slugs
18:08	vermiculus	I'd like to get the structure {1 "/lovely" 2 "/lovely/lovelier" 3 "/lovely/loveliest" 4 "/cool"}
18:08	justin_smith	oh, nice, a graph
18:09	vermiculus	:-)
18:10	justin_smith	vermiculus: what would you want if something had :parent 3?
18:10	justin_smith	what if 5 had :parent 6 and 6 had :parent 5? what would print then?
18:10	vermiculus	justin_smith: I'd say behavior is undefined in those cases.
18:10	vermiculus	Probably throw some sort of error.
18:11	justin_smith	so you have a representation that can do arbitrary graphs, but behavior is only defined for tree (directed and acyclic)
18:11	vermiculus	justin_smith: correct
18:11	vermiculus	turning the starting structure into a tree is, of course, a valid approach
18:16	TEttinger	,(let [structure {1 {:parent :root, :slug "lovely"}, 2 {:parent 1, :slug "lovelier"}, 3 {:parent 1, :slug "loveliest"}, 4 {:parent :root, :slug "cool"}}] (into {} (map (fn [[k {:keys [parent slug]}]] [k (str (get-in structure [parent :slug] "") "/" slug)]) structure))) ; not yet ready
18:16	clojurebot	{1 "/lovely", 2 "lovely/lovelier", 3 "lovely/loveliest", 4 "/cool"}
18:17	TEttinger	this only handles one level, which is the first problem
18:17	TEttinger	the lesser problem is not getting the opening / right
18:18	justin_smith	(get-in structure [parent :slug] "/")
18:18	justin_smith	shoud work!
18:19	justin_smith	oh, wait
18:19	justin_smith	never mind, your thing is good, you just need to make it recursive
18:34	vermiculus	I have a solution now, but it's pretty ugly :)
18:35	vermiculus	It's also a little cheat-y IMHO
18:35	vermiculus	https://gist.github.com/vermiculus/c8a531a86a0a65cdb9af4a466ed0721f
18:38	vermiculus	,(defn get-topic-children [topics topic-id] (map first (filter #(= topic-id (:parent (second %))) topics)))
18:38	clojurebot	#'sandbox/get-topic-children
18:39	vermiculus	,(defn get-routes [topics topic-id & [slug-so-far]] (let [children (get-topic-children topics topic-id) newslug (if (= topic-id :root) "" (str slug-so-far "/" (:slug (get topics topic-id))))] (if children (into (if (= topic-id :root) {} {topic-id newslug}) (map (fn [child-id] (if child-id (get-routes topics child-id newslug))) children)) {topic-id newslug})))
18:39	clojurebot	#'sandbox/get-routes
18:39	vermiculus	,(get-routes {1 {:parent :root, :slug "lovely"}, 2 {:parent 1, :slug "lovelier"}, 3 {:parent 1, :slug "loveliest"}, 4 {:parent :root, :slug "cool"}} :root)
18:39	clojurebot	{1 "/lovely", 2 "/lovely/lovelier", 3 "/lovely/loveliest", 4 "/cool"}
19:03	vermiculus	TEttinger: Feel free to ping me on twitter if you find a cleaner solution :-) (same username: @vermiculus)
20:02	asdf12z_	(defroutes app (GET "/ws" request (ws-handler request))) can someone explain to me how does "request" work here? this is compojure
20:02	asdf12z_	how is request even defined?
20:02	asdf12z_	like how is it possible to pass `GET` the result of (ws-handler request) when request isn't defined yet?
20:03	asdf12z_	i'm guessing its part of the macro magic
20:03	justin_smith	asdf12z_: defroutes is a macro, and it's binding the client's request object to the symbol 'request
20:03	justin_smith	asdf12z_: in normal clojure macros, request would be in a vector (eg let or defn)
20:04	justin_smith	I guess they decided compojure does not need a vector, because your handler is guaranteed to receive exactly one argument? not sure
20:05	asdf12z_	i guess i'm just confused as to how the code is evaluated and executed, so everything in defroutes doesn't actually eval yet, it's all fed in, and the macro then fills in for all the argument stuff like request
20:05	asdf12z_	is that about right?
20:05	justin_smith	well macros are allowed to do anything they want to their input - take it as is, evaluate it in the lexical environment, whatever
20:06	justin_smith	macroexpand might be informative here
20:08	asdf12z_	ok thanks justin_smith