#clojure – 2016-01-30

2016-01-30

00:01	Malnormalulo	going to have to go source diving some day to wrap my head round that
00:02	justin_smith	essentially whenever the reader finds # it takes the next form, and that form decides what to do with following data (and how much to consume)
00:02	justin_smith	eg #_ is a reader macro that says "take the next form and don't do anything beyond reading it"
01:04	macrolicious	in Emacs, when I C-x C-e (defn myfunction [foo] (str foo)), I get => #'testapp.core/myfunction in the minibuffer, but when I try to run (myfunction "bar") in the cider repl, I get an 'Unable to resolve symbol' error… what's going on?
01:05	macrolicious	To clarify, myfunction was in another buffer than the cider repl.
01:06	macrolicious	I'm not sure where/how to test individual functions after 'running' them with C-x C-e.
01:28	macrolicious	I guess it's more of an #emacs question, now that I think about it.
04:47	kenrestivo	namespace it was defined in was testapp.core. namespace you're running your repl buffer in is probably user
04:48	kenrestivo	if you change the namespace of your repl, it'll work.
04:48	kenrestivo	(ns testapp.core) might do ya
07:53	spuz	how do I load my clojure file into the repl such that I can call functions without giving the namespace?
08:04	kungi	spuz: you can use (:require [your.ns :refer [function-1 function-2]]) in your ns form
08:05	spuz	kungi, is there a way to do it without knowing the function names in advance?
08:17	loophole	spuz (:require [your.ns :refer :all])
08:17	spuz	loophole, thanks!
08:20	spuz	loophole, that doesn't seem to work
08:20	spuz	does it need some specific version of clojure?
08:20	loophole	spuz: one moment i will try it myself
08:23	loophole	spuz: (use 'your.ns)
08:23	loophole	spuz: I have to check the exact rquire syntax myself nut use should work anyways
08:24	loophole	spuz: s/nut/but/
08:24	spuz	but the style guide says: "Prefer :require over :use; the latter form should be considered deprecated for new code"
08:24	spuz	https://github.com/bbatsov/clojure-style-guide
08:24	loophole	spuz but you are talking about the repl?
08:24	spuz	yes
08:25	luma	in the repl, it's (require '[your.ns :refer :all])
08:25	luma	inside the ns form, it's (:require [your.ns :refer :all])
08:25	spuz	thanks luma
08:25	loophole	luma: haha... the ':'
08:26	spuz	yes that was it
08:26	loophole	never cut and paste
08:26	loophole	note to self
08:26	spuz	how do I unrequire something?
08:27	loophole	spuz: i have no idea
08:27	luma	(remove-ns '
08:27	luma	(remove-ns 'your.ns)
08:28	loophole	spuz: why not (require '[your.ns :as y])
08:28	spuz	?
08:28	loophole	spuz then you don't have to ubnload at all
08:29	loophole	spuz (y/the-command)
08:29	spuz	seems strange
08:29	loophole	spuz: instead of (your.ns/the-command)
08:29	spuz	is there somewhere where I can find all namespace functions enumerated?
08:29	luma	but why would you need to "unrequire" something?
08:30	loophole	spuz importing all function into your namespace is not a good thing outside the repl
08:31	spuz	luma, so that i can unpolute the current namespace
08:31	loophole	spuz that is what the the :as syntax is for
08:32	loophole	spuz: to keep aliases short so that it is convinient enough to use them instead of the full blown namespace
08:32	spuz	maybe I don't understand what refer does but I don't see how :as helps
08:33	loophole	spuz say you want to use clojure.string/join
08:33	loophole	spuz without refer you have to write (clojure.string/join ...)
08:34	loophole	spuz: with refer :as you give the clojure.string part an alias say 's'
08:34	loophole	spuz: now you can write (s/join ....)
08:35	loophole	spuz: you can now have a function in your own code that is named join and it won't interfere with s/join
08:36	loophole	spuz: when you use :refer :all
08:36	loophole	your own join method will collide with the clojure.string/join method
08:40	loophole	,(require '[clojure.string :as s])
08:41	clojurebot	nil
08:41	loophole	(s/join "X" [1 2 3])
08:41	loophole	,(s/join "X" [1 2 3])
08:41	clojurebot	"1X2X3"
08:42	loophole	,(defn join [xs] [:haha_no_join [xs]])
08:42	clojurebot	#'sandbox/join
08:42	loophole	,(require '[clojure.string :refer :all])
08:42	clojurebot	#error {\n :cause "denied"\n :via\n [{:type java.lang.SecurityException\n :message "denied"\n :at [clojurebot.sandbox$enable_security_manager$fn__835 invoke "sandbox.clj" 69]}]\n :trace\n [[clojurebot.sandbox$enable_security_manager$fn__835 invoke "sandbox.clj" 69]\n [clojurebot.sandbox.proxy$java.lang.SecurityManager$Door$f500ea40 checkPropertyAccess nil -1]\n [java.lang.System getProperty ...
08:43	spuz	try just refering join
08:45	spuz	,(require '[clojure.string :refer [join]])
08:45	clojurebot	nil
08:45	spuz	,(join "foo")
08:45	clojurebot	"foo"
08:45	spuz	,(join "foo" "foo")
08:45	clojurebot	"ffooofooo"
08:45	spuz	so that's the clojure.string join ^
08:45	spuz	now how do i get my custom join back?
08:45	loophole	spuz that's ok too. I think it depends a bit on style. the prfix makes it clear that you use some external function when you read the code.
08:46	spuz	,(defn join [xs] [:haha_no_join [xs]])
08:46	clojurebot	#error {\n :cause "join already refers to: #'clojure.string/join in namespace: sandbox"\n :via\n [{:type clojure.lang.Compiler$CompilerException\n :message "java.lang.IllegalStateException: join already refers to: #'clojure.string/join in namespace: sandbox, compiling:(NO_SOURCE_PATH:0:0)"\n :at [clojure.lang.Compiler analyzeSeq "Compiler.java" 6875]}\n {:type java.lang.IllegalStateException\...
08:46	loophole	spuz I always use the :as version
08:46	loophole	spuz in my code
08:47	spuz	so how do i get the previous definition of join back here?
08:47	loophole	spuz afaik the environemt repl will be restarted after a while
08:48	spuz	loophole, right... does that mean I have to restart everytime I want to change my own code?
08:48	spuz	it seems to defeat the point of the repl
08:49	luma	you can reload your file
08:49	ridcully_	just eval your defn again
08:53	spuz	if I use (require) to reload the file into the repl, it doesn't seem to actually bring in the changes
08:57	spuz	use of the repl in general just seems incredibly complex: https://github.com/clojure/tools.namespace#reloading-code-motivation
08:58	spuz	and as far as I understand the main motivation for using it slow compilation times?
09:01	mgaare	Slow repl startup
10:04	bcoburn	I'm trying to make a 'two-way' map where I can lookup key given val or val given key, is there a better way than doing (assoc {} key val val key) every time I want to add an entry?
10:15	dadinn	hi everyone
10:15	dadinn	anyone here is familiar with clojure zippers?
10:17	dadinn	I have found a behaviour which I cannot explain and it seems like a bug
10:18	dadinn	here is an example testcase presenting the behavior: http://pastebin.com/wQzH826Q
10:20	kwladyka	dadinn you don't have seqzip
10:20	dadinn	sorry I missed it from the example lol
10:20	dadinn	(def seqdat (list (list 1 2 3) (list 4 (list 5 6) 7) (list 8 9)))
10:20	dadinn	(def seqzip (zip/seq-zip seqdat))
10:21	dadinn	it's essentially the same structure as the veczip, but from seqs
10:23	dadinn	kwladyka: updated the link: http://pastebin.com/iWHUSnDC
10:23	dadinn	this one should have seqzip too
10:25	Malnormalulo	bcoburn: Per https://stackoverflow.com/questions/1183232/a-bi-directional-map-in-clojure, looks like it's either use a Java lib or roll your own bimap. Guava has one, reportedly
10:25	dadinn	oh noo, with sinax error too :P
10:25	kwladyka	dadinn for first look of eye it is not the same. your vector is nested one time more
10:26	kwladyka	,(list (list 1 2 3) (list 4 (list 5 6) 7) (list 8 9))
10:26	clojurebot	((1 2 3) (4 (5 6) 7) (8 9))
10:26	kwladyka	vs [[[1 2 3] [4 [5 6] 7] [8 9]]]
10:27	kwladyka	dadinn use '(1 2 3) instead of (list 1 2 3) - will be easier to read
10:27	dadinn	kwladyka: I didn't notice that ... oops
10:28	bcoburn	I think just having more keys is easier than both of those. I really should have searched first :(
10:28	dadinn	that vectorzipper was an example on clojuredocs so I just copied it to see if it really works like in the example
10:28	bcoburn	I guess all I'd need is a little function to call assoc
10:29	dadinn	and was a bit worried I don't get it why the down was behaving wierd..
10:29	Malnormalulo	bcoburn, Yeah, should be easy enough to abstract away. And assuming the map doesn't get too ginormous, the performance penalty of a naive approach won't be too bad
10:30	dadinn	thanks for helping
10:59	vise890	hey all. emacs question. has anyone managed to get cljr-find-usages and cljr-rename-symbol when working with clojure 1.5
11:10	dysfun	i get this strange error compiling a cljc file as cljs: Exception in thread "main" java.lang.AbstractMethodError: Method cljsbuild/compiler/SourcePaths._find_sources(Ljava/lang/Object;)Ljava/lang/Object; is abstract
11:10	dysfun	code is here https://github.com/jjl/automat/blob/cljc/src/automat/fsm.cljc#L25
11:11	dysfun	no line number or anything :)
11:47	justin_smith	dysfun: clojure 1.5 supports cljc?
11:48	justin_smith	dysfun: cljc is a 1.7 feature
11:48	justin_smith	oh, never mind, reading comprehension fail
12:33	dysfun	justin_smith: don't suppose you found the bug? :)
12:34	justin_smith	haha, no, that is the kind of error that is so weird that I would just run lein clean and try again
12:34	dysfun	yeah, but lein clean doesn't fix it :/
12:34	dysfun	it's probably a bug in potemkin.types/deftype+ :)
12:36	justin_smith	but that shouldn't even be a possibility when you are compiling cljs...
12:37	dysfun	you'd think, but notice it talks about java.lang.Object
12:37	justin_smith	it's a compilation error, cljs is compiled by clojure
12:38	dysfun	yeah, and i'm moderately ignorant of clojurescript's internals
14:04	sdegutis	What's a reasonably simple way to do different things to a value based on whether it's a string, keyword, sequence, or map, without needing extensibility for new types?
14:05	dysfun	(cond (string? p) ... (vector? p) ... :else ...)
14:05	justin_smith	or even condp class p
14:06	justin_smith	never mind, not that
14:06	dysfun	plus you're asking for cljs portability issues doing that
14:07	sdegutis	justin_smith: I was about to do condp type v but it seemed weird.
14:07	sdegutis	dysfun: I hate cljs so that's ok
14:07	dysfun	hate is a strong word
14:08	sdegutis	Correct.
14:08	dysfun	why do you hate cljs?
14:08	sdegutis	Perhaps hate is wrong.
14:08	sdegutis	Loathe?
14:11	sdegutis	jk hate works
14:11	sdegutis	Clojure is great and Datomic is genius.
14:12	dysfun	i think most of us don't use datomic actually
14:12	dysfun	we aren't their target customers
14:42	sdegutis	dysfun: who is?
14:42	sdegutis	dysfun: datomic is basically just a reall nice compromise between nosql and sql, I can't imagine who it's not right for
14:44	sdegutis	Anyway this task is too hard for my cognition to process.
14:48	justin_smith	sdegutis: it's not right for people who have large datasets or large throughput
14:48	justin_smith	I wish I could use it - we had to scale back our product because mongo wasn't delivering documents fast enough, and that was the fastest thing we found
14:58	sdegutis	justin_smith: mongo sucks when you have high-write and high-read, because every write slows down reads by locking /the entire db/
14:59	sdegutis	justin_smith: datomic is cool in how all reads/queries are basically free, because they happen in-process, and require no locking at all
15:00	sdegutis	justin_smith: with mongo and sql you have to have a super fast db server and your web server can be slow because it doesnt do much of the work on processing queries, but with datomic its reverse, the db server can be slow but the web server can be way faster
15:00	sdegutis	etc
15:00	justin_smith	sdegutis: multiple processes using the db, using it to send data, thus requiring frequent updates, datomic does not manage that nicely
15:00	sdegutis	justin_smith: meh
15:01	justin_smith	sdegutis: where datomic shines is if you can hold onto the same client side cache of things for a while - I'm not saying it doesn't work, but it doesn't work for our specific case
15:01	justin_smith	sdegutis: also we are using wired tiger, which does not lock the entire db for writes
15:01	sdegutis	justin_smith: you can put memcache between the web clients and the db server
15:03	justin_smith	sdegutis: will this work for thousands of writes a second?
15:08	sdegutis	naturally yes
15:58	creese	Has anyone created a back end for om.next that isn't datomic?
16:30	thesaskwatch	Hi, anyone here using cljs with node? I'm not sure I understand the dev workflow. Do you use cljs compiler watching and rebuilding and nodemon to autorestart the server or just cljs node repl somehow?
16:35	BRODUS	how can I `load-file` in a from a parent directory? Using ".." is not working
16:41	ridcully_	load-file from a plain repl with "../file.clj" works for me
16:41	ridcully_	is the error any useful?
16:48	BRODUS	ridcully_: no
16:48	BRODUS	ridcully_: just "No Such File or Directory"
16:49	BRODUS	ridcully_: I should mention that I'm not working in a project, its a just a .clj file in a directory that needs to read a clojure file in a directory above it
16:53	BRODUS	could it be because i started CIDER from another project?
16:55	trasto	Hi , I am new in clojure and have one question , how I can put one value for default in this form (let [[ v k] list]) ,is possible?
16:55	BRODUS	yep, that was the problem
16:56	trasto	I do not know how to do it
17:00	Mokuso	Hi. Would you recommend to someone to start learning Clojure, if he doesn't have much experience with Java and the Java environment? I have some experience with python and C# though.
17:01	Mokuso	(I don't mind the lisp/like looks of Clojure, what annoys me so far is that I don't really get the error messages, since they're Java related)
17:02	Mokuso	thx
17:11	dysfun	Mokuso: you get used to java. clojure was my first serious jvm programming experience
17:18	Mokuso	thanks dysfun. Just saw your answer, but I've got a dc as well
17:24	dysfun	er, dc?
17:28	Mokuso	disconnect
17:33	dysfun	well in any case, i think clojure is an entirely reasonable first language
17:33	dysfun	and you get used to the parentheses
17:38	Mokuso	Yeah, I don't mind. It's cool that the repl has autocompletion for the parentheses as CL
17:39	Mokuso	anyways, we'll see how it goes
18:05	justin_smith	trasto: what does "one value for default" mean?
18:30	justin_smith	Mokuso: the state of the error messages is because clojure per se doesn't really have error messages or error handling for the most part. If you make a mistake that hits the vm then you get a trace showing the state of the vm and who the callers were and some implementation details revealed by the problem - which is distinct from a true error report of course.
18:31	justin_smith	Mokuso: it's as if python didn't do error handling and you just got operating system level access errors
18:31	Mokuso	aha, interesting
18:31	Mokuso	yeah, it sounds cool
18:31	Mokuso	but you'll have to know how your VM works, to decipher the errors msgs
18:31	justin_smith	Mokuso: cool, haha - the error handling (or lack of any explicit sort of error handling) is probably the worst thing about clojure
18:31	justin_smith	Mokuso: exactly
18:32	Mokuso	I don't mind, investing time in the JVM seems promising.
18:32	Mokuso	Esp. since I don't have in mind writing code for low level applications
18:32	justin_smith	Mokuso: on the plus side, it's not hard to find out what was happening at a low level, on the minus side, it's not hard to find out what was going on at a low level :)
18:33	Mokuso	uhm, what's the difference between happening and going on ?
18:33	justin_smith	Mokuso: editing error on my part, I meant them to both be the same
18:33	Mokuso	Ah ok :>
18:34	justin_smith	Mokuso: but more seriously, the art of dealing with the traces is mostly digging through and looking for your own code, then use other things in the trace as needed as context clues to see where it went wrong
18:35	justin_smith	the usual culprits are numeric operations, string methods, or calling methods on null - clojure code actually tends to be very resiliant it's just that these things blow up when they hit the vm implementation level
18:35	justin_smith	generally clojure itself is very optimistic and instead of checking that args are valid just pass them to the next layer of abstraction hoping for the best
18:36	justin_smith	,(get 1 :a "default") ; obvious nonsense, works for implementation reasons
18:36	clojurebot	"default"
18:38	Mokuso	I'll probably start with a relevant book that explains how clojure is connected with JVM and all that stuff
18:38	justin_smith	the clojure.org docs are pretty good too
18:39	justin_smith	Mokuso: my "big picture" version is that clojure is a java library that generates jvm bytecode
18:39	Mokuso	heh
18:39	Mokuso	or a lisplike wrapper around Java classes perhaps
18:40	justin_smith	it's literally the truth though. It's a java lib (also runnable as a standalone program), you feed it text, it outputs bytecode, and it also contains the components needed to launch that bytecode as a program
18:40	justin_smith	Mokuso: kind of, yeah, but the outer layer is java - clojure itself is java code at the core, bootstrapped to clojure code for all but the most central stuff
18:41	Mokuso	aha..
18:41	justin_smith	so you have a java program, that defines a small lisp, then a bunch of lisp code it knows how to load, and all together that forms a usable bytecode compiler plus the stub needed to load and run that bytecode it generates
18:41	Malnormalulo	We call it a functional language, but really they're just IFn objects...
18:41	justin_smith	clojure programs are not standalone - they need the clojure runtime (since clojure is so meta / allows runtime definitions)
18:41	justin_smith	Mokuso: exactly!
18:42	justin_smith	so that's the bare basics, the code of clojure, and a good book or three, and you'll know all of it as well as any of us here
18:46	Mokuso	justin_smith, thanks a lots !!
18:46	justin_smith	np, glad I could help
18:46	justin_smith	Mokuso: oh, another cool thing that I can mention here is that clojure only has one mode of operation
18:46	justin_smith	Mokuso: what clojure does in the repl is exactly what it does when it reads your file and visa-versa
18:47	Mokuso	how else could it be ?
18:47	justin_smith	most languages allow using symbols before they are defined if they are defined in the same file
18:47	justin_smith	clojure doesn't, because it loads a file exactly the same way it reads your input at the repl, and if something isn't defined that's an error
18:48	justin_smith	Mokuso: if you look closely most languages have all sorts of special cases about how things run when the program is executing versus when things are being compiled and defined, but in clojure there is no split between those things
18:49	Malnormalulo	So it sounds like its compilation isn't super complex. It's more like ahead-of-time interpretation.
18:49	justin_smith	well, everything is always compiled
18:52	LucidTortoise	I am sure I will get some positive answers to this question: has anyone seen this talk?: http://www.infoq.com/presentations/Are-We-There-Yet-Rich-Hickey
18:53	LucidTortoise	I don't want to discuss the talk per se, but I do have one question?: What are the languages that embody his philosophy?
18:53	LucidTortoise	I suppose we have Clojure, Haskell, and other functional oriented languages. But what else fits the mold?
18:54	justin_smith	perhaps erlang?
18:54	LucidTortoise	Well, he does make a statement that "the world does not run by message passing", or something like that.
18:54	justin_smith	lokien: yeah, I grouped that with "other functional languages" - all mls would fit there ocaml included
18:55	justin_smith	LucidTortoise: oh yeah, fair enough, it's been a while since I saw that
18:55	LucidTortoise	So, is Erlang Smalltalk done right/functionally?
18:55	justin_smith	LucidTortoise: well you already mentioned the functional languages :)
18:55	lokien	justin_smith: but I'm sad when it's put together with "others"
18:55	justin_smith	it's not functional, I was trying to think of non-functional languages that come close to doing it right
18:56	LucidTortoise	I don't want to say I lost my enthusiasm for Smalltalk... but I think what I like most about Smalltalk is the contained, image based environment. Hm, maybe I should take a closer look at Self or Newspeak
18:57	LucidTortoise	lokien justin_smith That is my concern exactly, a paradigm does not sufficiently qualify a language.
18:57	LucidTortoise	So, any suggestions?
18:58	lokien	LucidTortoise: for how long have you been programming? I'm not trying to insult you or anything, I'm curious
18:59	LucidTortoise	Haha. Not long enough to even remotely be insulted by the question,.
19:00	lokien	so, for how long? :D
19:01	LucidTortoise	About 2 years, which honestly adds up to 2 months. I have been to inconsistent. I am one of those poser programmers who like talking and learning more about the language itself, then actually building something.
19:02	LucidTortoise	I have in the past month changed my mindset to actually be productive. I didn't realize how much of a book 4Clojure would be until I started using it today.
19:02	lokien	hey, I was like you for my first 10 months or so
19:02	lokien	and still am, but less
19:02	Malnormalulo	Yo same
19:02	LucidTortoise	Yeah, but got so boring being so... impotent.
19:02	lokien	LucidTortoise: we could do stuff together if you wanted
19:02	Malnormalulo	Spent my first year of programming doing pretty much nothing. I learned pretty much nothing.
19:03	lokien	I learned a lot, but did almost nothing :D
19:03	Malnormalulo	It didn't help that I found myself doing web development, which is exactly what I didn't want to be doing
19:03	LucidTortoise	lokien that would be fun. If you got a project going on, I would love to be another brain or just eyes. Or, if I think of something clever, you will be one of the first people I ask for help.
19:04	LucidTortoise	Malnormalulo Web Dev is such a trap. I think it is important, but unless you literally want to be making websites, there are so many other ways to use your programming skills.
19:06	Malnormalulo	Well see I applied for a job asking for SQL and Java knowledge. Offered, accepted, started work. They put me on an ASP.NET site.
19:06	Malnormalulo	It literally was a trap.
19:06	LucidTortoise	I say this because I actually tried Web Dev. A family friend wanted a website. I took this as an opportunity to learn a new technology, but didnt realize how much their is to learn.
19:06	justin_smith	there's companies out there that look for haskell experience then make you do java :P
19:06	LucidTortoise	The guy ended up getting what he need by signing up to Weebly
19:06	Malnormalulo	justin_smith, oh god why
19:07	justin_smith	Malnormalulo: they want java written by the kind of people that know haskell
19:07	justin_smith	Malnormalulo: also, they must think frustrated / resentful programmers write good code or something?
19:07	justin_smith	lol
19:07	Malnormalulo	I mean I guess they'll know better than to use instance variables like local variables
19:07	Malnormalulo	(Some of my coworkers do this.)
19:17	justin_smith	Malnormalulo: I mean that's just fine because you never use an object in more than one thread ever, I mean everyone knows that
19:18	justin_smith	of course if you use an object in more than one thread that would be totally insane but who uses objects in threads anyway
19:18	Malnormalulo	Ha well see, we don't. Want to know how we do multithreading? We start up a new JVM.
19:18	justin_smith	see, everything's fine then
19:18	justin_smith	lol
19:18	Malnormalulo	But we do reuse objects to avoid the overhead of instatiating new ones, so we have the same problem anyway
19:19	justin_smith	Malnormalulo: that's a great advantage with clojure actually, immutability makes thread stuff so much simpler
19:19	Malnormalulo	Yawp. One of many reason I really want to introduce it to our codebase.
19:30	trasto	justin_smith: one value default , sorry my english is bad
19:32	justin_smith	trasto: so something like (let [[v k] (or (not-empty list) [1])] ...) so that v would default to 1 but k would be nil if the input is less than 2 elements long?
19:36	trasto	yes but I need the second argument take the default value
19:36	justin_smith	oh, I misunderstood
19:40	trasto	with maps is possible with :or but is possible with vectors?
19:40	justin_smith	trasto: I don't know of a way - there might be but I don't think so
19:43	trasto	so the best form is transform this vector in one map... I think
19:58	justin_smith	(defn vec-default [v defaults] (concat v (drop (count v) defaults)))
19:58	justin_smith	,(defn vec-default [v defaults] (concat v (drop (count v) defaults)))
19:58	clojurebot	#'sandbox/vec-default
19:58	justin_smith	,(let [[a b c d] (vec-default [1 2] [:a :b :c :d])] {:a a :b b :c c :d d}) ; trasto
19:58	clojurebot	{:a 1, :b 2, :c :c, :d :d}
20:03	trasto	thanks justin_smith , to me it makes me complicated clojure
20:04	Mokuso	bah, dictionaries are annoying in any language :/
20:07	trasto	in clojure more than others XD
20:45	pulse207	/msg NickServ VERIFY REGISTER pulse207 nbrtbrukopxq
20:45	tolstoy	Heh. Oops!
20:47	justin_smith	hey that guy's password is a second teir superman villian
20:48	pulse207	dang guess I shouldn't use another superman villain, huh?
20:48	tolstoy	Ah, like Mister Mxyzptlk?
20:48	Mokuso	sounds like an alien friend of Rick's from Rick n Morty show to me
20:48	justin_smith	yeah, the one who fills in when Mxyzptlk is busy
20:49	justin_smith	haha
20:49	Mokuso	hehe, I think Mxyzptlk is a cool name
20:49	Mokuso	I'd name my dog that :P
20:51	tolstoy	My dog came pre-named. Jet. Not that he doesn't have a dozen names, depending on the time of day and my mood.
20:54	tier2villian	lets try this again
20:54	Mokuso	heh
20:58	tier2villian	so does anyone talk here?
20:58	justin_smith	yup, all things clojure are talked about here
20:58	tier2villian	well that's good. I figured I'd lurk, but there wasn't anything going on
20:59	justin_smith	,((get get get get) (get get get get) (get get get get) 42)
20:59	clojurebot	42
20:59	Malnormalulo	wat
20:59	justin_smith	Malnormalulo: it'll work in your own repl too
20:59	tolstoy	Well, it's Saturday night, and Clojurists are much in demand on the party circuit.
20:59	tier2villian	Ah, I should have known
21:00	justin_smith	tolstoy: funny enough, the above snippet is my favorite clojure party trick
21:00	Malnormalulo	I'm still trying to figure out why it works
21:00	justin_smith	just let me know if you need a hint
21:02	Malnormalulo	I'd expect it to try to cast `get` to a map and then fail
21:02	justin_smith	Malnormalulo: remember what I was saying about clojure and failures?
21:02	justin_smith	clojure is optimistic, it rarely validates inputs, if things are absurd it just keeps going unless it hits the bytecode (where things really do fail hard)
21:03	Malnormalulo	I guess I'd need to go dig into the implementation code to make sense of how it gets that far without a casting error
21:03	justin_smith	turns out get doesn't need a hash-map (there are other valid types to get from), and getting is not something that fails hard
21:04	justin_smith	Malnormalulo: if you took out the 42 it would return nil, if you turned the second (get get get get) into #{(get get get get)} it would return #'clojure.core/get
21:06	tolstoy	(get map key default-value) ... make sense. ((_ _ _ get) (_ _ _ get) (_ _ _ get) 42) -> (get get get 42) -> 42. Huh.
21:07	justin_smith	tolstoy: yup
21:07	tier2villian	I was wondering if it was just a trick to pass the default value back out
21:07	justin_smith	,(+()())
21:07	clojurebot	2
21:08	tolstoy	,(get map reduce 42)
21:08	clojurebot	42
21:08	Mokuso	(* 2 3 5 7 11 13 17 19)
21:08	clojurebot	suffusion of yellow
21:08	Mokuso	:(
21:08	Mokuso	(* 2 3 5 7)
21:08	clojurebot	suffusion of yellow
21:08	justin_smith	tier2villian: the base form is (get nil nil 42), then we add to this the fact that any instance of get can be replaced by (get get get get) and either of those nils can be replaced by just about anything...
21:09	Mokuso	(* 2 3)
21:09	clojurebot	suffusion of yellow
21:09	tier2villian	justin_smith: got it. that's cool
21:10	tolstoy	Looks like an excellent code-review troll.
21:10	justin_smith	,(+(+()())(/(*)))
21:10	clojurebot	3
21:11	justin_smith	,(+(/(+()()))(/(*)))
21:11	clojurebot	3/2
21:11	tier2villian	well I'm intrigued
21:12	justin_smith	that's just some second rate swearjure - the real deal is amazing but I am no master of swearjure
21:12	justin_smith	http://hypirion.com/musings/swearjure
21:13	tier2villian	That's one up on me. I don't actually know clojure, just looking for a new language to learn
21:13	justin_smith	oh shit this stuff makes clojure look terrible I'm so sorry
21:14	justin_smith	it's actually a very sane and readably language and these are bad code jokes we would never do in real code
21:14	tier2villian	Oh, I know. I never judge a language too quickly
21:15	Mokuso	does this bot get only the swearjure ?:P
21:15	tier2villian	(* 2 3 5 7 11 13 17 19)
21:15	clojurebot	suffusion of yellow
21:16	tier2villian	,(* 2 3 5 7 11 13 17 19)
21:16	clojurebot	9699690
21:16	tier2villian	weird
21:16	Mokuso	aha, maybe the comma
21:16	Mokuso	,(* 2 3)
21:16	clojurebot	6
21:16	tier2villian	I was watching you and wondering haha
21:16	justin_smith	Mokuso: absolutely not, the point of swearjure is that it is normal clojure - or at least understood by the normal clojure compiler
21:16	Mokuso	yeh :>
21:17	Mokuso	,(defn ackermann [m n] (cond (zero? m) (inc n) (zero? n) (ackermann (dec m) 1) :else (ackermann (dec m) (ackermann m (dec n)))))
21:17	clojurebot	#'sandbox/ackermann
21:17	Mokuso	,(ackermann 2 3)
21:17	clojurebot	9
21:17	Mokuso	,(ackermann 3 3)
21:17	clojurebot	61
21:17	Mokuso	,(ackermann 4 1)
21:17	tier2villian	I was very worried you were gonna pass it one of the big ones
21:17	clojurebot	eval service is offline
21:17	hyPiRion	4 1 is one of the big ones :p
21:17	Mokuso	not really
21:18	Mokuso	4 3 is one of the big ones
21:18	tier2villian	speak of the devil
21:18	Mokuso	and 4 2
21:18	Mokuso	but it should be able to calc 4 1
21:18	justin_smith	it was big enough for clojurebot to ditch
21:18	justin_smith	Mokuso: it can, but not in the tiny time slice you are allowed
21:18	Mokuso	yeh, it's ok
21:18	Mokuso	aha :)
21:18	justin_smith	this is to protect the poor bot from trolls, of course
21:19	Mokuso	you know guys, I found some lisp code at the rosetta stone project for this monster function, and even if it's optimized it crashes at (ack 4 3)
21:19	Mokuso	I was wondering what kind of optimization one would need to use to calculate such a big integer
21:19	hyPiRion	Oh and yeah, you don't have to know Swearjure-related things to learn Clojure. I don't think I've ever seen anything I've learned from Swearjure in production quality Clojure code
21:19	justin_smith	heh, I'd hope not!
21:19	Mokuso	heh :)
21:20	justin_smith	hyPiRion: maybe very basic things, like knowing you can do (apply * l) and if l is empty it returns 1
21:20	Mokuso	I'm trying to translate the code from CL to clojure anyways, but it crashed for the time being. Would you like to have a look? I can provide the lisp code as well for comparison (that works fine).
21:21	justin_smith	Mokuso: feel free to share a link
21:21	hyPiRion	justin_smith: oh yeah, right. (*) and (+) is handy to learn just to know what happens when you do reduce on an empty list
21:21	justin_smith	right
21:21	justin_smith	,(/ 2) ; related but not sweary
21:21	clojurebot	1/2
21:22	justin_smith	,(iterate / 2)
21:22	clojurebot	(2 1/2 2N 1/2 2N ...)
21:25	hyPiRion	Knowing about %& inside #(...) is also worthy. Rarely useful, but that one time you need it it's good to know
21:25	Mokuso	justin_smith, http://pastebin.com/9B3teGEw
21:25	hyPiRion	,(#(reduce + %&) 1 2 3 4 5 6)
21:25	clojurebot	21
21:25	justin_smith	Mokuso: so what's the error you get - stack overflow?
21:27	Mokuso	http://pastebin.com/EtLUf0YV
21:27	justin_smith	Mokuso: oh, you have the case syntax all scrambled
21:27	Mokuso	oh ?
21:28	justin_smith	Mokuso: every match clause in case needs the outer parens removed
21:28	justin_smith	cl -> (case x (m a) (m a)) clj -> (case x m a m a)
21:28	justin_smith	we use one less level of parens
21:28	Mokuso	ah !!
21:29	Mokuso	a bit confusing, but I'll give it a try
21:29	Mokuso	thanks :)
21:30	justin_smith	Mokuso: one more thing - remove the :else
21:30	Mokuso	maybe I'll use a cond instead
21:30	hyPiRion	Mokuso: https://www.refheap.com/114278 I think
21:30	justin_smith	just having an odd number of args suffices
21:30	justin_smith	with cond you also need to remove the parens around the matches
21:31	justin_smith	and replace each one with an equality test
21:31	justin_smith	*with case
21:31	Mokuso	this looks how it should be hyPiRion :)
21:33	Mokuso	yeah, it worked in the repl, but not through the core.clj, so I'll dig a bit more on that
21:33	justin_smith	so I use Math/pow instead of numeric-tower and (ackermann 4 2) simply returns Infinity
21:33	justin_smith	hah
21:33	justin_smith	wait, what worked in the repl?
21:33	Mokuso	the link hyPiRion gave :>
21:33	Mokuso	it's the correct 'translation' with the changes you mentioned
21:34	justin_smith	indeed (plus removing the redundant () on each case, which was not needed but is idiomatic)
21:34	Mokuso	ack 4 2 works fine, 4 3...I don't think I'll get a result :>
21:37	justin_smith	Mokuso: it took me for ever to stop writing (let [[a 0] [b 1]] (+ a b)) and variants, as someone who has coded scheme and common lisp in the past
21:39	Mokuso	It makes sense justin_smith. If you don't mind asking, what made you switch to clojure from those two?
21:39	Mokuso	*some habits are hard to break
21:40	justin_smith	Mokuso: I switched because I got hired to do clojure. I was hired because I had lispy experience, they were doing clojure and not one of the others because they needed to deploy to the jvm or at least have all the libs jvm would provide.
21:40	Kamuela	What’s a good explanation of the let form? I think it’s one that I’m not picking up so easily
21:41	justin_smith	Kamuela: it allows setting values to symbols that don't effect other cide
21:41	tier2villian	I could be wrong, but it's just a way to scope variables, right?
21:41	justin_smith	*other code
21:41	justin_smith	right
21:41	Mokuso	justin_smith, nice. Would you say that your background help you to learn clojure faster or had you wished you didn't know lisp/scheme before so you wouldn't have to unlearn all the extra stuff those languages had?
21:41	justin_smith	when you use def, you are changing something at namespace level, which could effect any of your other code
21:42	tier2villian	Okay, it's been a little while since I messed with scheme and that's my only lisp experience
21:42	justin_smith	Mokuso: definitely helped, most stuff was just simple translation - but I jumped ahead by far when I stopped treating clojure as "a weird lisp" and just dug into learning clojure as clojure
21:42	Mokuso	I'm asking, 'cos I'm considering some clojure related jobs for the future, and I'm wondering if I should go straight there or pass through scheme first.
21:42	justin_smith	tier2villian: so, in scheme you can use def to create locals
21:43	justin_smith	in clojure that's not a thing
21:43	Mokuso	Aha..thanks :)
21:43	tier2villian	justin_smith: oh so in clojure anything "def"'d is global?
21:43	justin_smith	Mokuso: if clojure gets to weird and confusing, plt-scheme or whatever they call it now is great, and is meant to be a language used to teach programming, so it has great tooling and documentation.
21:44	justin_smith	tier2villian: well, namespace level, so practically global, yeah
21:44	tier2villian	Mokuso: the racket community is also pretty welcoming, which is a plus
21:44	Mokuso	that's very interesting, Java is still calculating (ack 4 3). In scheme and CL it just crashed after a short time.
21:44	tier2villian	justin_smith: got it, thanks
21:45	justin_smith	Mokuso: numeric tower does promotion to unbounded bignums iirc
21:45	justin_smith	your cl may or may not do that
21:46	justin_smith	,(inc' Long/MAX_VALUE)
21:46	clojurebot	9223372036854775808N
21:46	justin_smith	,(inc Long/MAX_VALUE)
21:46	clojurebot	#error {\n :cause "integer overflow"\n :via\n [{:type java.lang.ArithmeticException\n :message "integer overflow"\n :at [clojure.lang.Numbers throwIntOverflow "Numbers.java" 1501]}]\n :trace\n [[clojure.lang.Numbers throwIntOverflow "Numbers.java" 1501]\n [clojure.lang.Numbers inc "Numbers.java" 1839]\n [sandbox$eval49 invokeStatic "NO_SOURCE_FILE" 0]\n [sandbox$eval49 invoke "NO_SOURCE_FIL...
21:50	Mokuso	ok, I've got an overflow after all, or close to that :>
21:50	Mokuso	ArithmeticException BigInteger would overflow supported range java.math.BigInteger.reportOverflow (BigInteger.java:1153)
21:50	justin_smith	that's a kind of overflow I have never seen
21:51	justin_smith	,(iterate *' Long/MAX_VALUE)
21:51	clojurebot	(9223372036854775807 9223372036854775807 9223372036854775807 9223372036854775807 9223372036854775807 ...)
21:51	justin_smith	oh wait, with one arg it's just identity
21:51	justin_smith	,(iterate #(*' % %) Long/MAX_VALUE)
21:51	clojurebot	(9223372036854775807 85070591730234615847396907784232501249N 7237005577332262210834635695349653859421902880380109739573089701262786560001N 52374249726338269874783614880766155793371912454611337886264179577532000370919343764787541041733925104025910035567032750922845842742640075519159173120001N 27430620343968443368695140184646988379527410343527824317354069354225552356596046115747958004859021025898780...
21:54	tier2villian	So question. I'm going to a 24 hour hackathon next weekend. Would it be unreasonable to try and pick up clojure and hope to have something to show for it?
21:55	justin_smith	that's one way to learn - you might want to make sure you have the basics for packaging and dependency management in check so you don't waste hackathon time on stupid stuff :)
21:56	tier2villian	alright. it really depends on my team I guess. If i end up flying solo, I'll probably give it a shot
21:56	justin_smith	not that clojure is bad at those things (far from it), but our tooling is weird at first to most people
21:56	tier2villian	weird in what way?
21:57	justin_smith	tier2villian: no global installs, instead you configure each individual project for hte lib versions it expects
21:57	justin_smith	which solves a lot of problems, but requires a bit more tedium up front when first starting
21:57	Mokuso	tier2villian, I've tried a hackathon like six months ago, but I went there without some concrete plan.
21:57	Mokuso	I'd advise you to have some idea before you go there
21:57	rhg135	Too awesome, controlling dependencies is something I miss when doing js
21:57	Mokuso	time flies fast :)
21:57	tier2villian	oh okay gotcha
21:58	tier2villian	Yeah, my first was last weekend actually
21:58	Mokuso	great experience though, no matter how you do in the end
21:58	tier2villian	got to try out mobile dev for the first time
21:58	Mokuso	you'll meet some people as well, so it's nice
21:58	tier2villian	Yeah, that was the best part
22:04	Mokuso	anyways, I'll better go get some sleep :)
22:05	Mokuso	thanks for the ack hack xD
22:25	princeso_	,(clojure.walk/postwalk #(do (prn %) %) [1 {:2 3}])
22:25	clojurebot	#error {\n :cause "clojure.walk"\n :via\n [{:type java.lang.ClassNotFoundException\n :message "clojure.walk"\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$1 run "URLClassLoader.java" 355]\n [java.security.AccessController doPrivileged "AccessController.java" -2]\n [java.net.U...
22:26	justin_smith	,(require 'clojure.walk)
22:26	clojurebot	nil
22:26	princeso_	,(clojure.walk/postwalk #(do (prn %) %) [1 {:2 3}])
22:26	clojurebot	1\n:2\n3\n[:2 3]\n{:2 3}\n[1 {:2 3}]\n[1 {:2 3}]
22:26	justin_smith	fyi :2 is an abomination
22:26	princeso_	what does that mean?
22:27	justin_smith	princeso_: it's an exaggerated why of saying "Not only do I not see any point to using :2 as a keyword, seeing it used makes me twitch with annoyance". Kind of joking.
22:27	justin_smith	why not just use the number 2?
22:28	princeso_	well the point was, there is a vector in the result [:2 3].
22:29	justin_smith	,(clojure.walk/postwalk #(doto % prn) [1 {2 3}])
22:29	clojurebot	1\n2\n3\n[2 3]\n{2 3}\n[1 {2 3}]\n[1 {2 3}]
22:29	justin_smith	princeso_: yes, hash-maps are made of entries, which are each two element vectors
22:29	justin_smith	,(seq {2 3})
22:29	clojurebot	([2 3])
22:29	justin_smith	,(seq {2 3 4 5})
22:29	clojurebot	([2 3] [4 5])
22:29	justin_smith	,(into {} [[2 3] [4 5]])
22:29	clojurebot	{2 3, 4 5}
22:31	princeso_	justin_smith: mmm ok. didnt know that. Im working on vectors, so there is going to be a hack
22:32	justin_smith	,(map-entry? [1 2])
22:32	clojurebot	false
22:32	justin_smith	,(map-entry (first {1 2}))
22:32	clojurebot	#error {\n :cause "Unable to resolve symbol: map-entry in this context"\n :via\n [{:type clojure.lang.Compiler$CompilerException\n :message "java.lang.RuntimeException: Unable to resolve symbol: map-entry in this context, compiling:(NO_SOURCE_PATH:0:0)"\n :at [clojure.lang.Compiler analyze "Compiler.java" 6688]}\n {:type java.lang.RuntimeException\n :message "Unable to resolve symbol: map-e...
22:32	justin_smith	,(map-entry? (first {1 2}))
22:32	clojurebot	true
22:32	justin_smith	(= (first {1 2}) [1 2])
22:32	justin_smith	,(= (first {1 2}) [1 2])
22:32	clojurebot	true
22:33	justin_smith	princeso_: the map-entry? function might help you
22:33	princeso_	godd: thanks justin_smith. you always rock!
22:36	princeso_	justin_smith: haha that "makes me twitch with annoyance" was epic. any way i kind of like how it looks :D
22:38	justin_smith	princeso_: I deal with learners a lot, so it makes me wonder if the person using it thinks : is a syntax that means "lookup key in a hash map"
22:38	justin_smith	kind of like in js
22:42	Malnormalulo	yeah, the keyword syntax isn't the most intuitive thing in the world
22:43	justin_smith	,(keyword " :: ::: ::: / / / ::: /")
22:43	clojurebot	: :: ::: ::: / / / ::: /
22:43	justin_smith	gotta love that clojure
22:43	justin_smith	to be clear, that returns a single keyword
22:43	justin_smith	,(namespace (keyword " :: ::: ::: / / / ::: /"))
22:43	clojurebot	" :: ::: ::: "
22:43	justin_smith	,(name (keyword " :: ::: ::: / / / ::: /"))
22:43	clojurebot	" / / ::: /"
23:12	princeso_	justin_smith: what could be possibly wrong whit postwalk, it says false to map-entry? [2 3]. And prewalk says yes.
23:13	justin_smith	princeso_: aha! post-walk is reconstructing the input, before your code gets to it
23:13	justin_smith	in retrospect I should have predicted that would be an issue
23:15	justin_smith	bbl