#clojure – 2015-09-05

2015-09-05

01:14	reutermj	How do you add metadata to a macro with a def? `(def ^{:some-meta 4} ~name 4) doesn't work.
01:19	amalloy	reutermj: http://stackoverflow.com/a/11920022/625403
01:23	reutermj	amalloy: ok so when I set print-meta and change the macro to `(def ~(vary-meta name assoc :some-meta 4) 4) it prints the correct meta data. But, calling (meta some-name) returns nil
01:24	amalloy	(meta #'some-name)
01:25	reutermj	ok that was mentioned earlier. What exactly does that reader macro do?
01:30	amalloy	,'#'x
01:30	clojurebot	(var x)
01:31	reutermj	thanks
01:31	reutermj	(inc amalloy)
01:31	lazybot	⇒ 300
02:42	TEttinger	(identity amalloy)
02:42	lazybot	amalloy has karma 300.
02:42	TEttinger	congrats
03:58	Quasimodem	I have experience with programming, java, c++, Pascal(good intro for me). I think what essentially is true in programming, is that it's more based on mindset, and how you use the language to benefit you.
06:21	ashwink005	can I convert a list of HashMaps, to a vector of HashMaps?
06:24	Rurik	ashwink005, yes, wrap the list in vec
06:24	Rurik	,(vec ())
06:24	clojurebot	[]
06:27	mavbozo	,(vec '({:a 1} {:b 2}))
06:27	clojurebot	[{:a 1} {:b 2}]
06:42	irctc	Hello everyone, is there any reason why clojure is not implemented in clojure?
06:42	Rurik	irctc, it is implemented in clojure
06:43	Rurik	irctc, https://github.com/clojure/clojure/blob/master/src/clj/clojure/core.clj
06:43	irctc	but why does 60% of the code base is written in java ?
06:44	luxbock	Rurik: it's only partly implemented in Clojure, though there is a separate projects that can read, analyze and emit JVM bytecode
06:45	luxbock	I wonder why the Clojure jar doesn't include the java files btw
06:45	luxbock	it would be nice if I could jump to the Java source location from my editor
07:00	sobel	there may be a distribution that includes source in the same jar but typically sources are omitted for brevity
07:05	clj-beginner	Hello.
07:06	clj-beginner	Can try take multiple expressions?
07:06	clj-beginner	Most of the examples that I have seen uses only one expression before catching
07:06	clj-beginner	is it possible to use multiple?
07:07	clj-beginner	I tried experimenting but I kept on getting a class cast exception error
07:07	luxbock	sobel: looking here I see that such a .jar exists https://repo1.maven.org/maven2/org/clojure/clojure/1.7.0/
07:08	luxbock	but using [org.clojure/clojure "1.7.0-sources"] doesn't seem to work, nor does it mention sources in the pom file
07:08	amalloy	http://central.maven.org/maven2/org/clojure/clojure/1.7.0/clojure-1.7.0-sources.jar
07:08	amalloy	luxbock: it's not a differently-named artifact
07:08	amalloy	it's the same artifact with a different qualifier - look up how to get sources from maven in general
07:08	amalloy	or maybe classifier? i forget
07:09	luxbock	amalloy: ok thanks
07:09	mavbozo	,(try (inc 1) (inc 2))
07:09	sobel	luxbock: sorry, i don't have the details, and i actually don't hope to step into Clojure code if I can help it :)
07:09	clojurebot	3
07:19	luxbock	I think :classifier "sources" is right, but I get the following stacktrace when I try to start my REPL: https://gist.github.com/luxbock/b78272185608adb6b7b8
07:20	luxbock	No matching method: unsignedShiftRight, compiling:(clojure/core.clj:1337)
07:21	luxbock	I feel like it's taunting me
07:23	luxbock	it did download the clojure-1.7.0-sources.jar though
07:27	luxbock	so I guess the -sources .jar only includes the sources and not the class files
07:29	luxbock	so you can't even start a REPL with it via clojure.main
10:40	ashwink005	can anyone give me a simple example how return a string containing "foo" x number of times
10:40	ashwink005	*how to
10:42	Rurik	,(apply str (repeat 3 "foo"))
10:42	clojurebot	"foofoofoo"
10:42	rhg135	(apply str (repeat 10 "foo"))
10:42	Rurik	ashwink005, this works? ^
10:42	ashwink005	Rurik: this can be done without loop?
10:43	ashwink005	cool
10:43	ashwink005	yup thanks
10:48	tomjack	should there be a "confirm before running a template you just downloaded" option for lein?
10:59	sobel	why?
10:59	clojurebot	sobel: because you can't handle the truth!
10:59	sobel	...guess i asked for that
11:00	sobel	tomjack: it's a CLI development tool. i'm thinking, probably not.
11:01	justin_smith	I could imagine a "delete this code that breaks the project to prove you've read the code the template generates"
11:02	justin_smith	but that would be weird
11:05	tomjack	I'm imagining camping in clojars on many distance 1 edits of popular templates..
11:06	justin_smith	oh, template-name typos
11:06	sobel	the correct way to manage that is to stop it at the source so the fewest number of people would be affected. beyond that, my strategy is don't take risks on precious machines. my code has been unpredictable in the past...
11:07	justin_smith	so "lein new rung" would send all your private ssh keys to my obfuscated email
11:07	sobel	the threat is within, i guess, is the lesson i take to security. there are also external threats but they are less likely to really mess things up for me.
11:07	justin_smith	tomjack: the problem is that a template can do arbitrary code at creation time - just cloning is enough to be screwed
11:08	justin_smith	s/cloning/using the template/
11:08	justin_smith	really, there should at least be an easy way to browse and approve a template before using (especially since versions are implicit...)
11:08	tomjack	right, in the lein new code it's "download, then immediately (require 'leiningen.new.whatever)"
11:09	sobel	this is perfect timing, as i contemplate converting a config file reader from to eval so i can put more interesting expressions in it
11:09	sobel	slurping edn, as it were
11:10	justin_smith	there's definitely room for an alternate, non-turing-complete template tool in the clojure ecosystem
11:10	sobel	think i'm gonna run with it, dangerous as it is. but i wonder what more cautious developers would do here, before exposing eval to essentially random files
11:10	sobel	i used to like the Velocity template language but most impls let you call into the host language from its ECMA-like macro language
11:10	sobel	other than that, i think it had a long of things right
11:11	justin_smith	sobel: my preference would be to let the user supply a function explicitly to be run
11:11	justin_smith	without having to just evaluate file contents - let them provide some implementation of a configuring protocol
11:12	sobel	so basically whitelist some functions
11:12	justin_smith	that's not what I said at all
11:12	sobel	figured. i don't exactly follow what you said.
11:12	justin_smith	if they want to run arbitrary code, use a code oriented interface, not eval on a text file
11:13	justin_smith	define a protocol that is used for config, and let them provide an implementation of that protocol
11:13	patrkris	does anyone here know how to specify an optional keyword in a map that includes a ? character in herbert?
11:15	sobel	er, "dependency injection in clojure" just crossed my search results. of all the things i am pretty damn sure i don't need in clojure, that tops my list.
11:16	justin_smith	sobel: running eval on a config file is dependency injection. In fact it is the worst kind of dependency injection.
11:17	sobel	that's one way to look at it
11:17	sobel	degenerate DI
11:17	sobel	maybe it's the DI framework i don't need. obviously i employ the concept liberally.
11:18	sobel	or non-obviously
11:18	justin_smith	sobel: I think with higher order functions available, DI is trivial
11:18	justin_smith	no more special than a loop
11:18	sobel	exactly
11:19	sobel	everything i used DI for in java is obviated by clojure
11:19	mavbozo	i call it Devilish Injection
11:19	justin_smith	I agree that we don't need frameworks in order to do it, but I still think it's better to define a protocol that a user can implement and pass to your code, rather than running an eval on a special file
11:19	sobel	it's a valuable practice in Java
11:20	sobel	justin_smith: fortunately i can get by with read rather than eval, but agreed
11:21	oddcully	patrkris: does adding two ? work (:lerl??)
11:22	patrkris	oddcully: it does. should've tried it. that's the obvious way :D thanks.
11:38	ashwink005	whats the clojure way of getting all rows in a db WHERE column example "contains" a substring
11:38	ashwink005	the best way I mean
11:40	ashwink005	anyone? someone knows mysql/sqlite?
11:41	mavbozo	ashwink005, what's wrong with select * from user where name LIKE '%jure%'
11:42	ashwink005	actually I have many such columns and many such values
11:42	ashwink005	was wondering if there was a cleaner way
11:43	mavbozo	cleaner way to generate the query?
11:44	mavbozo	or the fastest query?
11:53	sdegutis	Wouldn't (defn ^:memoize foo [bar] ...) be so cool?
11:54	ashwink005	mavbozo: nope a shorter way
12:03	mavbozo	ashwink005, i usually create a function that generates the query string
12:04	ashwink005	mavbozo: yeah actually now I'm doing the same :)
12:04	ashwink005	thanks
12:05	sdegutis	Is there a more condensed or idiomatic way to do this? (set! (. Stripe apiKey) secret-key)
12:06	mavbozo	ashwink005, it's the same thing i did in other prog-langs. I still haven't found the idiomatic clojure way.
12:06	ashwink005	mavbozo: hmmm
12:16	ashwink005	one small doubt, how do I change the value of a string in its lexical scope?
12:17	ashwink005	(str symbol "something") returns the concatenated string but doesn't append "something" to the beginning of symbol
12:18	ashwink005	some help please
12:19	ashwink005	google can't
12:22	RedNifre	maybe (str (str symbol) "something") ?
12:22	RedNifre	nvm I think I missunderstood what you are trying to do.
12:23	justin_smith	RedNifre: fyi (str (str x) y) is the same as (str x y)
12:23	mavbozo	,(let [c "c"] (str s "=me"))
12:24	clojurebot	#error {\n :cause "Unable to resolve symbol: s in this context"\n :via\n [{:type clojure.lang.Compiler$CompilerException\n :message "java.lang.RuntimeException: Unable to resolve symbol: s in this context, compiling:(NO_SOURCE_PATH:0:0)"\n :at [clojure.lang.Compiler analyze "Compiler.java" 6704]}\n {:type java.lang.RuntimeException\n :message "Unable to resolve symbol: s in this context"\n ...
12:24	justin_smith	ashwink005: strings are immutable
12:24	mavbozo	,(let [c "c"] (str c "=me"))
12:24	clojurebot	"c=me"
12:24	justin_smith	ashwink005: if you want something you can mutate, consider a functional restructuring using recursion perhaps, or you can use a StringBuilder
12:24	mavbozo	ashwink005, do you want the value of c becomes "c=me"?
12:24	justin_smith	$javadoc StringBuilder
12:24	lazybot	http://docs.oracle.com/javase/6/docs/api/java/lang/StringBuilder.html
12:24	ashwink005	mavbozo: yes
12:25	ashwink005	justin_smith: so I'll have to use a stringbuilder
12:25	ashwink005	or I can create a new variable?
12:26	justin_smith	ashwink005: sure, that too
12:26	ashwink005	okok got it strings are imutable.. like in java
12:26	justin_smith	,(let [a "c" b (str a \= a) c (str b \& b)] c)
12:26	clojurebot	"c=c&c=c"
12:26	justin_smith	ashwink005: in fact... ##(type "")
12:26	lazybot	⇒ java.lang.String
12:26	justin_smith	they are java strings :)
12:27	ashwink005	justin_smith: yeah I reckoned
12:27	ashwink005	thanks!
12:33	tmtwd_	, (list 'if true (cons 'do (println "yay")))
12:33	clojurebot	yay\n(if true (do))
12:34	tmtwd_	why is there the (if true (do)) there?
12:34	hyPiRion	because (println "yay") prints yay and returns nil
12:34	justin_smith	tmtwd_: that's the return value of he expression
12:34	justin_smith	,(cons 'anything nil)
12:35	clojurebot	(anything)
12:38	tmtwd_	oh
13:20	thesaskwatch	Hi .. I'd like to run some i/o tasks - a lot of them. Is there a way to partition them and run in let's say n threads at once?
13:24	thesaskwatch	Ok ... I guess it's just a partition, map and run a future
13:27	skeuomorf	So, I need to get the skinny on Clojure's concurrency story, from threads to core.async, any resources? Terseness with examples preferred
13:33	skeuomorf	Terseness and examples along with it*
13:36	justin_smith	skeuomorf: start with the docs on http://clojure.org/documentation for refs, agents, and atoms, then check out the relevant functions on http://conj.io
13:37	justin_smith	conj.io has more examples, but clojure.org is the better big-picture
13:38	justin_smith	also note that refs, agents, and atoms are three different strategies for managing concurrency, and each has their use cases (see also core.async, which is a whole other can of worms and also has its use cases)
13:39	skeuomorf	justin_smith: I read all these docs yesterday, haven't read the core.async ones
13:39	skeuomorf	justin_smith: They didn't mention any "threads", most of the talk was about how to "share" or "not share" resources in a sense
13:39	justin_smith	it's a whole other parallel system - you can use them together, but each (refs, agents, atoms, core.async) are usable on their own
13:40	justin_smith	skeuomorf: the simple way to make a thread is via future
13:40	justin_smith	skeuomorf: also, agents use a pool of threads for all operations - with agents the way to use a thread is hand a task to the agent
13:40	skeuomorf	Will take a look at that as well as the core.asyync docs
13:40	justin_smith	the agent will find and use a thread
13:41	skeuomorf	I see
13:41	justin_smith	skeuomorf: most of the time in my code, the threads are started by an http request (new client gets allocated a thread)
13:41	justin_smith	or a websocket connection
13:41	justin_smith	etc.
13:42	skeuomorf	Yeah, what I have in mind is something close, I will be using UDP though
13:42	skeuomorf	I am mostly trying to formulate my ideas in term of clojure abstractions instead of "objects" interacting with each other
13:43	justin_smith	UDP doesn't have connections though - so I guess it's more a thread per message
13:43	skeuomorf	Yeah, I will "fire off" multicast messages and occasional single destination ones
13:43	justin_smith	skeuomorf: you might want to check out aleph if you are listening for messages as well
13:44	skeuomorf	I stumbled upon that and it seemed interesting, will check it out
13:45	skeuomorf	When should one use defrecord instead of making a (defn make-record [] {:myid id :whatever 1})
13:46	justin_smith	skeuomorf: once you go so far as having a special constructor, use a defrecord
13:46	justin_smith	skeuomorf: if you are creating maps ad-hoc, maybe you don't need a record
13:46	justin_smith	of course the real clincher is if you want to use protocols so that clients can provide behaviors in some system - then you really want defrecord
13:47	skeuomorf	nah, I am kinda making "instances" of a certain map structure
13:47	skeuomorf	Yeah, I will mostly define a protocol
13:47	justin_smith	skeuomorf: "instances" is enough reason to make a defrecord. If you are formalizing it, go ahead and formalizing it.
13:47	justin_smith	skeuomorf: for a protocol you need a defrecord because protocols dispatch by type, not keys
13:48	skeuomorf	Yeah, I figured that much
13:48	justin_smith	records are pretty lightweight, and mostly maps in every way that is useful, so I would jump over to using one as soon as you would give it a special name or constructor
13:48	skeuomorf	I see
13:49	justin_smith	skeuomorf: but the other thing you were talking about was being less OO
13:49	justin_smith	I think the key to that is think less about data types, and more about flows of data
13:49	justin_smith	*one key, at least
13:49	skeuomorf	Well,,
13:50	skeuomorf	I am thinking in flows of data alright, my problem is that I will have multiple "instances" and each one will affect the other in the same function
13:51	skeuomorf	so, 2 instances > function > 2 new instances
13:51	justin_smith	skeuomorf: I have a middleware that attaches a creation time, unique id, and client id to messages. This is fp because I ignore the type of the thing coming in (it just needs to be a type that lets me assoc). This is in contrast to expecting message senders to use my constructor which attaches that data.
13:51	justin_smith	skeuomorf: counting instances of things - so these things are tied to side effects and/ or state?
13:52	skeuomorf	well, both
13:52	skeuomorf	I am implementing SCAMP
13:52	skeuomorf	Which is a probabilistic gossip protocol
13:52	skeuomorf	re: http://research.microsoft.com/pubs/67296/ieee_tocs.pdf
13:52	justin_smith	OK - this is a different sense of "protocol" than I was using earlier
13:53	skeuomorf	oh, I know, don't worry
13:53	skeuomorf	:)
13:53	justin_smith	just making sure signals aren't getting crossed
13:53	skeuomorf	Yeah yeah, I got you
13:53	justin_smith	skeuomorf: a great idea I picked up from stuartsierra is that you should use FP for logic and computation and use OO for state.
13:54	justin_smith	and clojure has various ways of helping bring those together
13:54	justin_smith	a consequence of that, is the OO part of your code will often be singletons
13:54	justin_smith	(and of course in pure FP the concept of a singleton makes no sense)
13:55	joncol	Is there any way of having "lein new app" create a Mercurial repository instead of Git?
13:55	skeuomorf	well, let me tell you the mutable state "behavior" in this protocol
13:55	justin_smith	anyway - stepping away from the keyboard, but will be around later
13:55	justin_smith	go ahead and describe, I just can't reply right away
13:55	skeuomorf	justin_smith: Ok, nvm then, thanks for helping :)
13:55	justin_smith	maybe someone else here is interested too
13:55	skeuomorf	I will mess around anyways
13:56	skeuomorf	maybe will do an impl tonight
13:58	oddcully	joncol: lein new does not create a git repo (at least not for me)
13:58	oddcully	joncol: but it creates a .hgignore file (beside a .gitignore one)
13:58	joncol	oddcully: Oh, missed that :)
14:07	sineer	Hey hey! I got a question about CPU load averages
14:08	sineer	when running inside a KVM my server is idle yet I see varying CPU load averages... Is it that I somehow see the load average of a CPU that I'm sharing with another KVM instance?
14:09	sineer	I have the same idle server image running on two different KVM host and the load averages are always very much diferent, one can be at 0.95 while other is at 0.10 for instance
14:09	kitallis	I get a "java.lang.ClassNotFoundException: jsr166y.ForkJoinPool" when running lein repl, anyone know what that means?
14:10	Rurik	kitallis, are you running it in a project dir?
14:10	kitallis	yeah
14:11	kitallis	don't understand, this was fine a while back, not sure what I changed
14:12	Rurik	google says jsr166y is some concurrency library
14:12	oddcully	kitallis: bisect it
14:12	kitallis	yeah it says "java.lang.ClassNotFoundException: jsr166y.ForkJoinPool, compiling:(clojure/core/reducers.clj:56:21)"
14:13	kitallis	it's happening on all projects
14:13	oddcully	kitallis: same as here maybe? http://grokbase.com/t/gg/clojure/12c9wa1haj/exception-when-loading-clojure-core-reducers
14:13	kitallis	I think it's some global thing I messed up
14:13	oddcully	java version then?
14:37	dfens	If I have a map {:a 1} why do both (:a {:a 1}) and ({:a 1} :a) work? Isn't it confusing to have two ways to get the value of :a?
14:39	amalloy	dfens: why does (+ 1 5) work as well as (+ 5 1)? that's gotta be confusing too, right?
14:40	amalloy	keywords and maps are both functions, because it may be convenient to use either of them as functions in different contexts
14:41	dfens	amalloy: Ok sure thing. I guess I'll have a better grasp of that when I come across these different contexts :)
14:42	amalloy	dfens: well, examples are easy: ##[(map {:a 1, :b 2} [:a :b]) (map :a [{:a 1 :b 2} {:a 2 :b 1}])]
14:42	lazybot	⇒ [(1 2) (1 2)]
16:00	cryptack	looking for some understanding between just deffn inside a function and using letfn?
16:01	justin_smith	cryptack: defn inside a function makes a top level binding
16:02	justin_smith	cryptack: letfn makes multiple functions, with only local bindings, which can refer to each other recursively without declarations needed
16:03	cryptack	so if I were to do (defn f1 [x] (defn f2 [y] y) (f2 x)) then that means that f2 can be called from outside of f1?
16:03	justin_smith	,(letfn [a ([x] (b (b x))) b ([x] (+ x 21))] (a 0))
16:03	clojurebot	#error {\n :cause "Don't know how to create ISeq from: clojure.lang.Symbol"\n :via\n [{:type java.lang.IllegalArgumentException\n :message "Don't know how to create ISeq from: clojure.lang.Symbol"\n :at [clojure.lang.RT seqFrom "RT.java" 535]}]\n :trace\n [[clojure.lang.RT seqFrom "RT.java" 535]\n [clojure.lang.RT seq "RT.java" 516]\n [clojure.lang.RT first "RT.java" 661]\n [clojure.core$fi...
16:03	justin_smith	cryptack: yes
16:03	cryptack	got it
16:03	cryptack	I’m assuming the same with just fn then?
16:03	justin_smith	,(letfn [(a [x] (b (b x))) (b [x] (+ x 21))] (a 0))
16:03	clojurebot	42
16:03	cryptack	like an named fn
16:04	justin_smith	cryptack: (let [a (fn [x] (b (b x))) b ([x] (+ x 21))] (a 0))
16:04	justin_smith	err
16:04	justin_smith	,(let [a (fn [x] (b (b x))) b ([x] (+ x 21))] (a 0))
16:04	clojurebot	#error {\n :cause "Unable to resolve symbol: b in this context"\n :via\n [{:type clojure.lang.Compiler$CompilerException\n :message "java.lang.RuntimeException: Unable to resolve symbol: b in this context, compiling:(NO_SOURCE_PATH:0:0)"\n :at [clojure.lang.Compiler analyze "Compiler.java" 6704]}\n {:type java.lang.RuntimeException\n :message "Unable to resolve symbol: b in this context"\n ...
16:04	justin_smith	cryptack: unlike fn and let, letfn lets you forward reference
16:04	justin_smith	eg. for mutal recursion
16:05	cryptack	ok
16:05	justin_smith	notice the let version of my prior letfn fails because of the binding order
16:05	cryptack	justin_smith: okay
16:06	cryptack	justin_smith:
16:06	cryptack	justin_smith: thanks!
16:41	irctc	hello
16:43	irctc	is there a way to replace the current process with an other one in clojure
16:43	irctc	pretty much like exec() in C
16:44	irctc	i'd like a clojure script to ... just become a python script :p
16:55	skeuomorf	irctc: I don't know about "replace the current process" but checkout https://docs.oracle.com/javase/7/docs/api/java/lang/Runtime.html
16:55	skeuomorf	irctc: You'd access that via the Clojure Java interop facilities
16:56	irctc	hmmm
16:56	irctc	but i don't know any clojure :/
16:56	skeuomorf	Then, what are you doing writing clojure?
16:57	irctc	it's for a code golf achievement
16:58	irctc	i need to find a solution to a problem in clojure
16:58	irctc	i solved the problem in python
16:58	irctc	want to write a clojure script that would call my python scipt
16:58	irctc	:P
16:58	irctc	just did that with the bash achievement
17:01	justin_smith	(do (clojure.java.shell/sh "your-script.sh") (shutdown-agents) (System/exit 0))
17:02	justin_smith	that exits after the script instead of before though
17:02	justin_smith	there's no way in java to do a normal exec because windows sucks
17:59	xzilend	Hi there, I'm relatively new to clojure/functional/declarative programming, and was wondering if anyone could suggest improvements to this gist (https://gist.github.com/adairdavid/f7983b15f63773340151) to better follow a functional/declarative style?
18:03	justin_smith	xzilend: instead of nested if you could try cond - I'm not sure if that is more functional, but I find it easier to parse
18:05	neoncontrails	Could someone help me understand the control flow of a function that evaluates serially, but rebinds in parallel?
18:05	neoncontrails	,(doc recur)
18:05	clojurebot	No entiendo
18:06	justin_smith	neoncontrails: well, you can't do what you are describing with recur
18:06	neoncontrails	recur
18:06	neoncontrails	(recur exprs*)
18:06	neoncontrails	Special Form
18:06	neoncontrails	Evaluates the exprs in order, then, in parallel, rebinds the bindings of the recursion point to the values of the exprs.
18:06	justin_smith	recur only works in the tail position, so can't be invoked in parallel
18:06	neoncontrails	Execution then jumps back to the recursion point, a loop or fn method.
18:06	justin_smith	err, oh that's a different kind of parallel...
18:07	justin_smith	neoncontrails: what it means is that the recur bindings are not applied in series the way let bindings are
18:07	justin_smith	neoncontrails: in let, you can refer to the value of other bindings in the same let binding block, because they are evaluated in series
18:07	neoncontrails	I thought I understood this, but I'm getting some funny outputs which might be explained by semi-arbitrary ordering of variable rebindings on the recursion
18:07	justin_smith	,(let [a 0 b (inc a) c (inc b)] c)
18:07	clojurebot	2
18:08	justin_smith	neoncontrails: the bindings inside recur don't refer to the values of other bindings in the recur
18:08	justin_smith	they refer to the values in scope when recur is called
18:09	neoncontrails	I see. Gotcha. So no referring to the (first s) of some sequence that's getting repeatedly dropped on the recursion, then
18:10	neoncontrails	Within the recur statement, that is
18:10	justin_smith	,(loop [a 0 b 10] (if (> a b) (+ a b) (recur (* a b) (* b 0.9)))
18:10	clojurebot	#<RuntimeException java.lang.RuntimeException: EOF while reading>
18:10	sg2002	Hello. Anyone having any problems with the latest cider? I get No active nREPL connection even though there is one.
18:10	justin_smith	neoncontrails: well you can refer to first s, just be aware of which s it binds to
18:11	justin_smith	neoncontrails: inside the recur it will be whatever s was bound when this recursive call started
18:11	justin_smith	inside the loop declaration, it is only the initializer and doesn't effect future values when recurring
18:11	justin_smith	sg2002: I find that when cider does that I need to clean up my elc files, restart emacs, then reinstall cider
18:12	neoncontrails	Hmm. Let me pastebin my function, maybe you can tell me if I'm doing something illegal inside the recur statement
18:12	justin_smith	sg2002: #clojure-emacs might be able to offer more help, I stopped using cider because of how often it broke backward compatibility.
18:13	sg2002	justin_smith: Oh, never knew about that channel. Thank's for the tip, there are some weird byte-compile bugs that happen once in a blue moon.
18:14	justin_smith	sg2002: in my experience what was happening is that they were breaking api compatibility with their old code versions, which made the byte compiled code break
18:14	justin_smith	and like every release would do this
18:16	neoncontrails	justin_smith: http://pastebin.com/4dtCrL7G
18:17	justin_smith	neoncontrails: those bindings should work...
18:17	neoncontrails	It's perfectly likely there's just a bug in the logic, I just want to make sure I'm using the primitives correctly
18:17	justin_smith	yeah, that looks like a perfectly cromulent usage of recur
18:17	neoncontrails	Okay, cool. I'll treat it as a bug in the logic then. :)
18:17	neoncontrails	Thanks!
18:17	neoncontrails	(inc justin_smith)
18:17	justin_smith	the thing about parallel vs. serial bindings is a bit of a finicky point
18:17	lazybot	⇒ 294
18:17	sg2002	justin_smith: That's pretty weird, since package.el generally recompiles that stuff every time.
18:18	justin_smith	sg2002: maybe they don't describe their dependencies properly...
18:18	justin_smith	because I definitely fixed my problems by wiping out my package managed elisp code
18:18	neoncontrails	Yeah, what... precisely does it mean, exactly?
18:18	neoncontrails	I understand the difference between serial and parallel
18:19	amalloy	neoncontrails: (= (count s) < 3) ??
18:19	justin_smith	what it means is that in eg. let one let binding can refer to the value of the one right before it
18:19	lazybot	amalloy: What are you, crazy? Of course not!
18:19	neoncontrails	I am not sure what it means to interleave them
18:19	justin_smith	oh, yeah that is super weird!
18:19	justin_smith	(inc amalloy)
18:19	lazybot	⇒ 301
18:19	justin_smith	I missed that one
18:19	justin_smith	you likely want (< (count s) 3)
18:20	justin_smith	what you did was test if (count s), <, and 3 are all the same
18:20	justin_smith	which of course is trivially false
18:20	justin_smith	(unless someone is doing bad bad things to your comparison operators)
18:20	amalloy	and the (second uncompressed) looks like it ought to be (first compressed)
18:21	amalloy	neoncontrails: you know there is a much easier way to implement RLE, right? you are just doing it this way as a loop/recur exercise?
18:21	neoncontrails	amalloy: Do tell!
18:22	neoncontrails	I am doing this as an exercise, but I'm always interested in learning efficient, better ways to solve problems. :)
18:22	amalloy	look at ##((fn rle [s] (apply str (mapcat (juxt count identity) (partition-by identity s)))) "aaabddcejkkeddddddd")
18:22	lazybot	⇒ "3(\\a \\a \\a)1(\\b)2(\\d \\d)1(\\c)1(\\e)1(\\j)2(\\k \\k)1(\\e)7(\\d \\d \\d \\d \\d \\d \\d)"
18:22	amalloy	er
18:22	amalloy	##((fn rle [s] (apply str (mapcat (juxt count first) (partition-by identity s)))) "aaabddcejkkeddddddd")
18:22	lazybot	⇒ "3a1b2d1c1e1j2k1e7d"
18:23	justin_smith	you clojure wizards and your fancy repl tricks
18:23	justin_smith	I tell ya what
18:23	neoncontrails	Too cool. I'm going to meditate on that one for a bit, brb
18:24	justin_smith	neoncontrails: many of those functions are worth a very deep meditation and practice and mastery
18:24	justin_smith	(inc juxt)
18:24	lazybot	⇒ 23
18:24	justin_smith	(inc comp)
18:24	lazybot	⇒ 2
18:25	neoncontrails	Wait what's going on. Are you giving the language primitives karma
18:25	oddcully	we give even rubber ducks karma
18:25	justin_smith	yes, it's a tridition here
18:25	justin_smith	(inc rubberduck)
18:25	lazybot	⇒ 6
18:25	justin_smith	*tradition
18:26	justin_smith	while I'm at it
18:26	justin_smith	(dec flatten)
18:26	lazybot	⇒ -7
18:26	neoncontrails	Hahahahaha. Clojurians, you crack me up. :)
18:26	amalloy	RIP flatten. never forget
18:26	oddcully	boo flatten
18:26	amalloy	(dec tridition)
18:26	lazybot	⇒ -1
18:27	justin_smith	amalloy: sometimes I also pronounce things atrociously, it's like I have a gibberish demon trying to crawl its way out
18:28	amalloy	i spell concise right about one time in three
18:28	amalloy	got it wrong here, before backspacing
18:29	justin_smith	also my handwriting is very bad (though I have been trying to improve that lately because it's a nice break from screen/keyboard oriented stuff) - so all methods of conveying words have an added noise layer
19:18	Matachines	hey guys, new-ish to clojure/cljs, was wondering what the commonly used library for generating statistics is (stuff like mean/standard deviation, etc)
19:19	bacon1989	interesting, I don't even know what scientific libraries there are
19:19	justin_smith	Matachines: yeah, there's incanter for that http://incanter.org/
19:19	Matachines	thanks justin_smith
19:19	Matachines	!
19:19	justin_smith	it does graphing too
19:19	Matachines	perfect
19:20	justin_smith	I do graph analysis for my day job, we've been intending to start adding statistical analysis to our bag of tools for making metrics
19:21	bacon1989	justin_smith: you ever use gorilla repl for fast sketches?
19:21	justin_smith	bacon1989: no, I've intended to try it but haven't yet
19:21	justin_smith	bacon1989: and there's another similar one, the name is escaping me...
19:21	bacon1989	i've used it before, and found it pretty awesome
19:21	bacon1989	especially when working with people who don't know clojure
19:22	justin_smith	seems like it would be a kickass learning tool
19:22	bacon1989	ya def, I agree
19:23	justin_smith	though my tried and true is to only do things that work when you run "java -jar clojure.jar" because eliminating tooling problems from teaching is so nice
20:20	justin_smith	neoncontrails: ##(let [m (java.util.HashMap.)] (.put m :a 0) (.put m :b 1) m)
20:20	lazybot	⇒ {:b 1, :a 0}
21:06	justin_smith	,@(reify clojure.lang.IDeref (deref [this] "OK"))
21:06	clojurebot	"OK"
22:36	justin_smith	woohoo, just got my delivery estimate for "Clojure Applied" - I guess that means they have an official book release date.
23:17	neoncontrails	How would you express this logic more beautifully? http://pastebin.com/5C8sMp9i
23:17	neoncontrails	I know I'm making it about 4 times more complicated than it needs to be
23:23	bacon1989	oh neat function
23:24	neoncontrails	Thanks -- just a little exercise from 'Cracking the Coding Interview'
23:25	TEttinger	,((fn [v colls] (map #(if (some #{v} %) (repeat (count %) v) (seq %)) colls)) 5 [[1 2 3] [4 5 6] [7 0 8]])
23:25	clojurebot	((1 2 3) (5 5 5) (7 0 8))
23:25	amalloy	(defn if-any-then-all [x colls] (for [coll colls] (if (some #(= % x) coll) (map (constantly x coll)) coll)))
23:26	amalloy	TEttinger: you have to be careful with #{x}: what if someone calls this with x=nil?
23:26	TEttinger	ah, I was wondering which was preferred
23:26	neoncontrails	nice! I like the comparison of your approaches
23:26	TEttinger	(inc amalloy)
23:26	lazybot	⇒ 302
23:27	neoncontrails	(inc amalloy)
23:27	lazybot	⇒ 303
23:27	neoncontrails	(inc TEttinger)
23:27	lazybot	⇒ 65
23:27	TEttinger	I haven't seen (constantly x coll) before
23:27	TEttinger	(doc constantly)
23:27	clojurebot	"([x]); Returns a function that takes any number of arguments and returns x."
23:28	TEttinger	... possibly for good reason
23:28	TEttinger	,(constantly 5 [1 2 3])
23:28	clojurebot	#error {\n :cause "Wrong number of args (2) passed to: core/constantly"\n :via\n [{:type clojure.lang.ArityException\n :message "Wrong number of args (2) passed to: core/constantly"\n :at [clojure.lang.AFn throwArity "AFn.java" 429]}]\n :trace\n [[clojure.lang.AFn throwArity "AFn.java" 429]\n [clojure.lang.AFn invoke "AFn.java" 36]\n [sandbox$eval76 invokeStatic "NO_SOURCE_FILE" 0]\n [sandb...
23:30	neoncontrails	I was just about to ask about that
23:31	neoncontrails	I understand it at each step of the way, but there
23:31	TEttinger	,(defn if-any-then-all [x colls] (for [coll colls] (if (some #(= % x) coll) (map (constantly x)) coll)))
23:31	clojurebot	#'sandbox/if-any-then-all
23:31	TEttinger	,(if-any-then-all 5 [[1 2 3] [4 5 6] [7 0 8]])
23:31	clojurebot	([1 2 3] #object[clojure.core$map$fn__4537 0x29a1cd66 "clojure.core$map$fn__4537@29a1cd66"] [7 0 8])
23:31	TEttinger	ugh
23:31	TEttinger	,(defn if-any-then-all [x colls] (for [coll colls] (if (some #(= % x) coll) (map (constantly x) coll) coll)))
23:31	clojurebot	#'sandbox/if-any-then-all
23:31	TEttinger	,(if-any-then-all 5 [[1 2 3] [4 5 6] [7 0 8]])
23:31	clojurebot	([1 2 3] (5 5 5) [7 0 8])
23:32	TEttinger	it was a misplaced paren is all
23:33	amalloy	ah, indeed. i'm just mashing stuff out in irc
23:33	amalloy	hm, maybe it's time to look back into erc
23:33	neoncontrails	Constantly works in an interesting way, I notice
23:33	neoncontrails	,(map #(constantly %) (range 10))
23:33	clojurebot	(#object[clojure.core$constantly$fn__4371 0x432ae0b5 "clojure.core$constantly$fn__4371@432ae0b5"] #object[clojure.core$constantly$fn__4371 0x3406ad86 "clojure.core$constantly$fn__4371@3406ad86"] #object[clojure.core$constantly$fn__4371 0x226a5319 "clojure.core$constantly$fn__4371@226a5319"] #object[clojure.core$constantly$fn__4371 0x72759ff5 "clojure.core$constantly$fn__4371@72759ff5"] #object[clo...
23:34	bacon1989	man, what other channels let's you mess around with the language in them?
23:34	bacon1989	fucking clojure
23:34	TEttinger	,(map constantly (range 10))
23:34	clojurebot	(#object[clojure.core$constantly$fn__4371 0x28b15282 "clojure.core$constantly$fn__4371@28b15282"] #object[clojure.core$constantly$fn__4371 0x119fe9ad "clojure.core$constantly$fn__4371@119fe9ad"] #object[clojure.core$constantly$fn__4371 0x19a665e5 "clojure.core$constantly$fn__4371@19a665e5"] #object[clojure.core$constantly$fn__4371 0x7b6baa8a "clojure.core$constantly$fn__4371@7b6baa8a"] #object[clo...
23:34	amalloy	bacon1989: a lot of them
23:34	bacon1989	like what?
23:34	amalloy	haskell, python, java are a few i know of
23:34	TEttinger	haskell has lambdabot
23:34	amalloy	probably ruby, i would be very surprised if not
23:34	bacon1989	oh right
23:35	bacon1989	I guess they're all interpreted
23:35	TEttinger	(lambdabot is apparently very hard to change by anyone who didn't write it, despite being open source)
23:35	amalloy	no, java isn't
23:35	amalloy	neither is clojure really, we just have eval
23:35	TEttinger	haskell is compiled, but it does have a REPL
23:35	TEttinger	scala has a bot
23:36	TEttinger	multibot IIRC, it can do multi-line output to a certain limit
23:36	bacon1989	interesting
23:36	amalloy	anyway, an irc bot is a pretty standard thing for a programming language, because programmers want it so badly
23:36	TEttinger	perl6 has camelia and glrelia, the latter of which is meant to show changes made in the GLR branch of the code
23:36	bacon1989	also, isn't Java9 supposed to have a repl soon?
23:37	amalloy	plot twist: java 9 is groovy
23:37	neoncontrails	Heh, cute
23:37	neoncontrails	,(reduce + (map (constantly 1) [:a :b :c]))
23:37	clojurebot	3
23:37	bacon1989	amalloy: haha
23:37	TEttinger	you can compile java 9 today, it actually isn't as hard as 7 or 8
23:37	TEttinger	(and yes, it starts up faster)
23:37	bacon1989	TEttinger: that is exciting
23:37	TEttinger	they reorganized a lot of stuff, and still are, so it only loads core modules at startup
23:38	bacon1989	so that should mean clojure will start faster?
23:38	bacon1989	I wonder if i'll ever see the day when clojure can be used for command-line tools
23:38	TEttinger	somewhat yes. clojure still has its own lib to run, but less overhead from the JVM itself should help
23:38	TEttinger	pixie or an SSD :)
23:39	bacon1989	been looking at pixie
23:39	bacon1989	also, been looking at racket
23:39	bacon1989	(since John Carmack seems to like it)
23:39	TEttinger	I'm looking at None, which has unfortunately less clojure influence, more traditional scheme (no immutable stuff that I can tell)
23:41	TEttinger	it's very early in development it seems, but if you're targeting specifically the things that clojure doesn't (real-time low-level stuff), then None seems like a decent Lisp to use? https://bitbucket.org/duangle/none/overview
23:43	bacon1989	neat, i'll check it out
23:44	TEttinger	I suspect None will be more usable in a few months
23:46	bacon1989	personally I find it interesting because i've done a lot of work in lua