#clojure – 2016-03-14

2016-03-14

02:47	MONODA	I have a fully qualified symbol, how can I get the value associated with it?
02:47	MONODA	(eval A) works but I've been told eval is evil and usually not necessary
02:51	ben_vulpes	,(def A :foo)
02:51	ben_vulpes	,A
02:51	clojurebot	#'sandbox/A
02:51	clojurebot	#error {\n :cause "Unable to resolve symbol: A in this context"\n :via\n [{:type clojure.lang.Compiler$CompilerException\n :message "java.lang.RuntimeException: Unable to resolve symbol: A in this context, compiling:(NO_SOURCE_PATH:0:0)"\n :at [clojure.lang.Compiler analyze "Compiler.java" 6688]}\n {:type java.lang.RuntimeException\n :message "Unable to resolve symbol: A in this context"\n ...
02:51	ben_vulpes	,(println A)
02:51	clojurebot	:foo\n
02:51	dysfun	MONODA: ns-resolve ?
02:56	MONODA	That'll give me the var
02:56	MONODA	what I want is the actual value
02:59	opqdonut	you can deref the var
03:01	opqdonut	,((deref (ns-resolve 'user 'clojure.core/clojure-version)))
03:01	clojurebot	"1.8.0"
03:02	MONODA	of course, thanks
03:50	bendlas	has somebody figured out, how to use a recent cider with custom started piggieback clojurescript repl?
05:31	sagittarian	n
06:11	dazlow	How do I make leiningen to build another leiningen project inside my project and use it? I've modified some stuff in a clojar library but not sure if changes will see the upstream
06:12	MJB47	i think https://github.com/technomancy/leiningen/blob/stable/doc/TUTORIAL.md#checkout-dependencies
06:12	MJB47	is what you want
06:14	dazlow	Ok I'll check that out
06:14	kwladyka	Is any shortcut for: (if bar (bar foo) foo) ?
06:15	dysfun	not in core, probably somewhere on the internet
06:15	dysfun	part of the normal clojure writing process is noticing repeatable things and defining them as utility functions
06:17	urzds_	Hello!
06:18	urzds_	I see a weird error after creating a project using `lein new compojure `: Exception in thread "main" java.io.FileNotFoundException: Could not locate //handler__init.class or //handler.clj on classpath., compiling:(/tmp/form-init5006717142541663053.clj:1:73)
06:18	urzds_	Any idea what's going on here? I ran the same thing yesterday on my other computer and it worked...
06:19	MJB47	kwladyka: if you are expecting bar to be a map and foo a keyword you can do:
06:19	MJB47	,(let [bar nil] (or (:foo bar) :foo))
06:19	clojurebot	:foo
06:19	MJB47	but outside of those conditions it gets more complicated :(
06:20	ridcully_	urzds_: are your namespaces sane? are your file locations matching the ns?
06:20	dysfun	isn't that (get bar :foo :foo) ?
06:20	kwladyka	MJB47 thx. Unfortunately it is a little more complicated.
06:20	MJB47	dysfun: indeed it is, dont know why i overcomlicated it lol
06:21	urzds_	ridcully_: I just tried the command again with `lein new compojure folder` instead of `lein new compojure . :force` and compared the differences: Apparently the latter form creates a garbage project.clj where it uses "." in weird places instead of falling back to a sane default for the current directory.
06:21	urzds_	ridcully_: Thanks, though!
06:40	kwladyka	i messed in my mind... is it possible to use anonymous fucntions with -> and ->> ?
06:40	kwladyka	,(-> 2 (fn [x] 3))
06:40	clojurebot	#error {\n :cause "Parameter declaration 2 should be a vector"\n :via\n [{:type java.lang.IllegalArgumentException\n :message "Parameter declaration 2 should be a vector"\n :at [clojure.core$fn invokeStatic "core.clj" 4375]}]\n :trace\n [[clojure.core$fn invokeStatic "core.clj" 4375]\n [clojure.core$fn doInvoke "core.clj" 4357]\n [clojure.lang.RestFn invoke "RestFn.java" 490]\n [clojure.lan...
06:41	ridcully_	,(-> 2 ((fn [x] 3)))
06:41	clojurebot	3
06:45	kwladyka	hmm
06:45	dysfun	kwladyka: (fn will be read later
06:45	ridcully_	"hmm" is the proper reaction. that construct there is just ugly ;)
06:46	kwladyka	;)
06:49	ridcully_	for your earlier question: not shorter ((or bar identity) foo)
06:54	kwladyka	ridcully_ sounds good
07:10	m_m	Hi. Is it possible to create light processes/threads in clojure like in erlang ? I mean for example 100.000 on reasonable amount of memory.
07:13	MasseR	clojure threads are OS threads. So, afaik no
07:13	MasseR	But, the threading is done automatically with thread pools
07:28	m_m	How about actors etc ?
07:30	dysfun	no, we don't have actors, we use other mechanisms
07:30	dysfun	core.async is a popular choice. it models 'channels' (like from go)
07:31	dysfun	there's also manifold which operates on similar lines but it built atop netty
07:32	dysfun	the execution of those is modelled by the flow of data and uses an erlang like 'lightweight thread' mechanism based on a thread pool
07:33	dysfun	it is very easy to write something that behaves like an actor in core.async
08:11	kwladyka	#(or (nil? %) (= region %)) <- how to write better this condition? I tried with sets, but nil value makes a problem. I need to know the value is nil or region
08:17	ridcully_	i guess if you call it? what about contains? ,(contains? #{nil :a} nil)
08:18	ridcully_	also if this is an important check, then maybe a anon fn is not the right place? make it a defn with a nice name and the need to "compress" it vanishes.
10:51	dysfun	ridcully_: symbolic programming, yo :)
10:52	justin_smith	(-> x ((fn [] ...))) isn't any worse than (-> x (f)), and many prefer that over (-> x f)
10:53	justin_smith	((fn [] ...)) means you are calling the fn immediately, and indeed that's what you are telling that form to do
10:56	sdegutis	What is f? (f [1 2 5] [3 4]) => [1 2 3 4 5]
10:57	justin_smith	into
10:57	justin_smith	err, no that is wrong
10:57	sdegutis	Hmm. Never mind actually.
10:57	sdegutis	Thanks :)
10:58	justin_smith	(comp vec sort into) heh
10:58	sdegutis	I actually meant this: (f [1 2 3 4 5]) => [3 4 5]
10:58	sdegutis	Ah, nthrest.
10:58	justin_smith	or (partial drop n)
10:58	sdegutis	Hmm. Interesting.
10:59	justin_smith	which might be the same as nthrest actually
10:59	dysfun	i often find that i want a variant of comp which puts the params given up front after the params given later
10:59	sdegutis	,(source nthrest)
10:59	clojurebot	Source not found\n
10:59	sdegutis	Weird, nthrest uses loop, pos? seq, rest, dec, and recur.
10:59	justin_smith	it's eager, yeah
11:00	sdegutis	Okay. So it's the same as drop but the only difference being it's eager.
11:00	sdegutis	Makes sense.
11:00	justin_smith	drop uses a volatile
11:00	justin_smith	(for the transducer arity that is)
11:02	sdegutis	Oh wait, destructuring does this more easily.
11:02	sdegutis	Woot.
11:03	dysfun	destructuring is pretty ace
11:39	mr_rm	is anyone using Atom editor with proto-repl plugin? I can't seem to get a working repl and not sure why
12:19	justin_smith	opqdonut: for the case where you have a fully qualified symbol, it makes more sense to just use resolve instead of ns-resolve. But ns-resolve is good if you have eg 'str/join and the ns maps clojure.string :as str
12:52	opqdonut	justin_smith: thanks, I had forgotten about resolve
13:56	amalloy	nthrest. that's not a function i've seen used a lot. nthnext i use occasionally myself; i think i'd forgotten nthrest even exists
13:57	tolstoy	Is there a handy lib that'll turn raw XML into hiccup-like syntax?
13:58	justin_smith	tolstoy: how close does clojure.data.xml get you?
13:59	tolstoy	I think it's the same as clojure.xml: {:tag :foo :attrs {:a "1"} "data"} rather than {:foo {:a "1"} "data"}.
13:59	justin_smith	I assume you mean [:foo {:a "1"} "data"]
13:59	tolstoy	yeah.
14:00	amalloy	tolstoy: why would you do that? hiccup data structures are a bear to work with
14:00	justin_smith	that looks like a trivial transformation, but you could also see how well enlive works on xml
14:01	amalloy	enlive style structures are way better to consume. hiccup is popular because it's easy to produce
14:02	tolstoy	Can you use enlive with just random XML?
14:02	amalloy	of course
14:03	tolstoy	I have this "interesting" API where you ssh into a device with an old school menu, and instead of entering a number, you send blocks of XML.
14:03	tolstoy	Then you get XML back (blocks), as well as the menu stuff.
14:04	tolstoy	Fortunately, no namespace stuff.
14:06	tolstoy	I really just need to pull data out. I guess it's zippers, or some java-interop Xpath.
14:06	tolstoy	Or regex, actually.
14:06	justin_smith	tolstoy: I've had great luck with clj-tagsoup when it comes to data that is easy to detect regardless of nesting in doc structure
14:06	amalloy	tolstoy: just parse the data with c.d.xml and get a tree back. i bet you it'll be easy to get data out of without any extra tools
14:09	tolstoy	clj-tagsoup parses into hiccup-like syntax, which is what I asked for, but I bet just using the raw parse from clojure.xml is probably best.
14:10	justin_smith	tolstoy: oh, I meant the streaming mode (the truly soupy one), but yeah, if clojure.data.xml works, just use that
15:09	sdegutis	Ring is such a pain.
15:18	sdegutis	I'm using ring.middleware.flash/wrap-flash and I have returned {:status 200 :flash (:flash request) :body ...}, but the (:flash request) of the next request is nil.
15:37	sdegutis	Hi.
16:08	dysfun	flash requires sessions
16:10	dysfun	and you have to wrap flash and sessions in the right order
17:12	sdegutis	dysfun: But I have sess -- ooh! ordering!
17:12	sdegutis	dysfun: thanks, I'll try that out
17:13	sdegutis	Ugh I hate Ring middleware. It's so prone to error.
17:13	sdegutis	I honestly think I'm just gonna rip out the middleware I have and combine them into a single function that wraps my Compojure handler.
17:14	sdegutis	Middleware is just such an error prone design.
17:22	benjyz1	hi. I'm having a small issue trying to return json from ring
17:23	benjyz1	I wrap the routes with (wrap-json-body) (wrap-json-params) (wrap-json-response)
17:24	benjyz1	and get back an escaped string... "{\"posted\":\"ping\"}"
17:27	dysfun	sdegutis: yes, but don't do that
17:28	sdegutis	dysfun: why not
17:28	dysfun	by all means write a function that wraps a handler with all the others, but don't try and combine them into one nasty middleware
17:29	dysfun	you can do something like this https://github.com/irresponsible/qarma/blob/master/src/qarma/middleware.clj
17:30	TimMc	that's irresponsible
17:30	TimMc	;-)
17:30	dysfun	yeah and i'm working on irresponsible/emotional :)
17:30	dysfun	also irresponsible/asylum
17:31	dysfun	and every c++ programmer's favourite, irresponsible/overload
17:33	dysfun	it was just another silly name. i never thought it would makes so many other silly names even sillier
17:55	rhg135	now we need responsible/X
17:56	dysfun	not really as satisfying though, is it?
17:56	dysfun	:)
17:56	rhg135	irresponsible/fun
17:57	dysfun	the best kind!
17:58	rhg135	oh the puns!
17:58	dysfun	thing is though i've been choosing all the names assuming they were freestanding, so it's always a bonus when it works great together
18:10	sdegutis	dysfun: hmm, reordering wrap-session and wrap-flash didn't help at all, in fact it made it worse, since the flash no longer worked at all.
18:10	sdegutis	dysfun: which suggests that the wrap-flash middleware is working correctly and I'm using it correctly
19:48	spieden	yo clojureverse
23:48	mmercer	completely unsafe for work but it is so cool i have to post it! http://www.cam4.com/hotnoielya
23:49	TEttinger	that looks like spam, from that link
23:50	mmercer	no, it is just a cam girl with dildo backwards in her twat, making it look like she has a penis
23:50	mmercer	it is glorious
23:51	mmercer	the is the skills women need, not programming
23:53	mmercer	(dildo has balls btw :) )