#clojure – 2016-02-26

2016-02-26

00:15	seanirby	is there a way i can associate an nrepl server with a clojure app
00:18	seanirby	wait nvm, i may be confused
03:44	akonring	\list
07:48	freddy_	hi friends
09:04	kungi	Can I limit the number of threads to 1 while running my tests on the JVM?
09:58	nicola1	did cider-refresh stop working for anyone else here in the past couple of days?
09:59	nicola1	i can't seem to load any module in the repl anymore more than once
10:11	kwladyka	nicola1 maybe you need a licence?
10:11	kwladyka	nicola1 trial end?
10:13	kwladyka	nicola1 restart intellij? update?
10:14	nicola1	this cider https://github.com/clojure-emacs/cider
10:17	nicola1	i think upgrading the package broke something, but pinning (from cask) the git version of cider won't work at all (cider fails to load some "cider-test" file, even if i specify cider's latest commit on which melpa's version is based on)
10:20	hexa	anyone ever tried to cider-jack-in with a lein-exec script ?
10:37	kwladyka	nicola1 i use cider with intellij, so i don't know situation in eamcs
10:55	sdegutis	Isn't this sufficient for turning Clojure rows into a CSV string? https://gist.github.com/sdegutis/55febb1065df0a85208e
10:56	sdegutis	Of course, the two "," instances could be replaced with an optional variable as well as the "\n" instance. But even then, it's, like, complete. Right?
11:00	TimMc	kungi: You mean limit the total number of threads in the JVM, or change whether your tests are multi-threaded?
11:05	kungi	TimMc: I was asking the wrong question
11:05	kungi	TimMc: I found my bug an d have to think about it for the weekend
11:11	TimMc	:-)
11:18	justin_smith	nicola1: CIDER emacs upgrading in place always breaks
11:19	justin_smith	nicola1: the two things that typically fix it are deleting all .elc files related to clojure stuff (including things like clojure mode that aren't strictly CIDER), and deleting everything clojure related entirely then installing the version you want
11:20	justin_smith	personally I opted out of using a tool that breaks when upgraded, but that's a personal decision of course
11:24	nicola1	justin_smith: i've had it break a few times but it's usually resolved quickly; i'd be happy using an older version (that's why in my cask setup i specify the git commit to pull from) but in that case it fails to even start
11:24	justin_smith	nicola1: no it's not about using an older version
11:24	nicola1	btw i'm erasing the whole .cask directory when reinstalling, no success though
11:25	justin_smith	it's that updating without deleting first breaks it
11:25	sdegutis	justin_smith: I have not had problems upgrading CIDER
11:25	justin_smith	oh
11:25	justin_smith	sdegutis: congratulations
11:25	sdegutis	justin_smith: I've had to find the right version numbers but that's about it
11:25	justin_smith	how often do you upgrade?
11:25	sdegutis	Like twice a year at this rate
11:25	sdegutis	That's about how often Cider comes out with new versions tho
11:25	justin_smith	sdegutis: that's why it is OK, it breaks when you upgrade
11:25	sdegutis	what breaks?
11:25	justin_smith	CIDER
11:25	justin_smith	random crap
11:25	justin_smith	everywhere
11:26	justin_smith	sdegutis: normally, in emacs, when a package has a new version you can just pull it in
11:26	sdegutis	ok
11:26	sdegutis	justin_smith: sorry you've had bad experiences with it :(
11:26	sdegutis	justin_smith: i normally delete the old version and pull in the new version for upgrades
11:27	justin_smith	sdegutis: I had a coworker who would turn .cljc files into clj / cljs files because he did not have a CIDER new enough to work with cljc properly and refused to update because it would break :(
11:27	sdegutis	justin_smith: that would be frustrating indeed
11:29	TimMc	justin_smith: o_o
11:29	TimMc	I feel like as long as you have paredit, further editor support is not really all that necessary.
11:30	sdegutis	so, unrelated: i'm getting closer this week to finally using component in our whole app!
11:30	sdegutis	I'm still trying to figure out how to make the router be able to be a component.
11:30	justin_smith	TimMc: that's my take as well - though auto-indent that behaves properly is also very nice
11:30	sdegutis	I like the idea of the router and the route-handler being separate components. That's how duct does it right?
11:31	justin_smith	sdegutis: the way I would do that next time is passing a hash-map containing all the handlers in the system (each component adding to it as needed) and then finally having the router pull out the functions and middlewares it uses from that map
11:32	justin_smith	I don't know duct though
11:32	sdegutis	justin_smith: hmmm interesting to have each component have its own handlers
11:32	justin_smith	or middlewares
11:33	justin_smith	each stateful thing probably has the ability to offer its state to another handler, or a handler that accesses its state (if not both)
11:33	sdegutis	justin_smith: ignore the duct comment, I just meant that's how weavejester's ring-component lib works, it allows the ring-jetty-adapter to be wrapped in a component which can take another component as the handler
11:33	justin_smith	got it
11:34	justin_smith	yeah, you could make one component that contains the http-adaptor and another that constructs the handler, or combine them. The former would be a small thing without the handler / middlware definitions.
11:37	sdegutis	hmm
11:37	sdegutis	man, so many options
11:37	sdegutis	arg
11:38	justin_smith	sdegutis: clearly we need to get 1250 people to try each option, and then tabulate the total complexity and error rate of each resulting codebase and then we can calculate the objective best choice
11:39	sdegutis	agreed
11:40	justin_smith	sdegutis: my analog watch only allows setting in the forward direction, and is 15 seconds fast, and this makes me angy
11:40	justin_smith	*angry
11:40	sdegutis	*hangry?
11:40	justin_smith	I need to spin it almost 12 whole times to get it right and even then what are the chances I get it perfect that time
11:41	justin_smith	sdegutis: also I am permanently hangry, because I decided to lose weight. This is a seperate topic and completely off topic.
11:42	sdegutis	justin_smith: why does your time need to be so accurate? are you a train conductor for a living?
11:43	justin_smith	sdegutis: wait I thought I was an engineer
11:43	sdegutis	hahahaha i get your joke
11:43	justin_smith	OK different kind of engineer my bad and maybe I should not even use that term because we are not certified and I did not go to engineering school
11:43	justin_smith	well, that's a load of my mind, thanks
11:44	justin_smith	sdegutis: realistically my watch could be 10 minutes off and nobody at work would never notice
11:45	sdegutis	justin_smith: all the clocks in our house are off from each other by many minutes and seconds
11:45	justin_smith	I'm gonna get a watch that just blinks 12:00 all the time
11:46	sdegutis	well its always 12:00 somewhere!
11:48	justin_smith	sdegutis: blinking 12:00 is a totem, capturing the spiritual energy of all misconfigured devices and software everywhere.
11:53	sdegutis	:D
11:53	sdegutis	hi
11:55	sdegutis	TIL you shouldn't use anonymous functions for things so much because they don't have metadata
11:55	sdegutis	,(meta (fn []))
11:55	clojurebot	nil
11:55	sdegutis	Literally impossible to determine its arglists.
11:55	justin_smith	but hey you could put meta on it
11:55	sdegutis	Oh right lol
11:59	justin_smith	,(defn has-arity [f n] (try (apply f (repeat n nil)) true (catch clojure.lang.ArityException _ nil) (catch Throwable t true)))
11:59	clojurebot	justin_smith: Excuse me?
11:59	justin_smith	haha
11:59	justin_smith	sdegutis: the above thing is an abomination, but it correctly tells you whether a function has a given arity
11:59	justin_smith	I probably should have named it has-arity?-lol-don't-use-this
12:00	sdegutis	Actually
12:00	sdegutis	got an idea brb
12:00	justin_smith	oh no I gave sdegutis an idea I'm scared
12:01	sdegutis	you will regret it
12:03	Bronsa	sdegutis: no function has arglist metadata
12:03	Bronsa	it's been that way since 1.3.0
12:04	sdegutis	IT WORKS
12:05	justin_smith	sdegutis: how about a fn-with-arglists macro?
12:05	sdegutis	https://gist.github.com/sdegutis/62f0b4177f01cf331218
12:05	sdegutis	justin_smith: even better
12:05	justin_smith	oh, man...
12:06	sdegutis	it's like pretty legit kinda!
12:06	Bronsa	there's with-local-vars for that
12:06	justin_smith	sdegutis: instead of the let / gensym you could just do (let [v# (defn x# ~@stuff ...)] ...)
12:06	justin_smith	Bronsa: with-local-vars attaches the kind of metadata defn would?
12:06	sdegutis	justin_smith: oh right!
12:07	sdegutis	I forgot x# does gensym for me
12:07	Bronsa	justin_smith: no, right
12:07	justin_smith	sdegutis: I MEAN YOU WERE USING IT RIGHT THERE ALREADY COME ON
12:07	justin_smith	get it together, man
12:08	sdegutis	updated
12:08	sdegutis	https://gist.github.com/sdegutis/62f0b4177f01cf331218
12:09	sdegutis	this is probably the cleverst thing ill ever accomplish in clojure
12:10	justin_smith	sdegutis: (defmacro fn+ [& stuff] `(doto (defn n# ~@stuff) (partial ns-unmap ns)))
12:10	justin_smith	sdegutis: tested in my repl, works
12:10	sdegutis	oh man
12:10	sdegutis	I was just about to type "i kinda wanna find out how to use doto on this thing)
12:10	justin_smith	now you know!
12:11	TimMc	That partial doesn't need an extra set of parens?
12:11	justin_smith	TimMc: nope
12:11	justin_smith	err...
12:11	TimMc	you sure?
12:11	justin_smith	TimMc: you are correct!
12:12	justin_smith	TimMc: the ns-unmap silently misbehaved
12:12	sdegutis	justin_smith: wait doesnt that require comp meta :name too?
12:12	sdegutis	or are you able to just give that a var?
12:12	sdegutis	cuz it says 'sym' in the docstring
12:12	sdegutis	(doc ns-unmap)
12:12	clojurebot	"([ns sym]); Removes the mappings for the symbol from the namespace."
12:12	justin_smith	sdegutis: I think it does
12:12	justin_smith	sdegutis: yes, fixing
12:12	sdegutis	yeah so that shuldnt work and doesnt work here
12:13	sdegutis	i trieda comp version but i think i got it wrong cuz it no worky
12:14	sdegutis	dang this tricky
12:15	justin_smith	defmacro fn+ [& stuff] `(doto (defn n# ~@stuff) (->> meta :name (ns-unmap ns)))) ; TimMc sdegutis fixed
12:16	justin_smith	thanks for the quality QA
12:16	sdegutis	oh man so smart
12:16	sdegutis	justin_smith: wins
12:18	sdegutis	justin_smith: https://gist.github.com/sdegutis/62f0b4177f01cf331218
12:18	sdegutis	this is just terrible
12:18	sdegutis	why would you contribute to such a terrible invention justin_smith
12:18	sdegutis	and TimMc
12:18	sdegutis	how terrible of a macro
12:18	sdegutis	my goodness
12:19	sdegutis	so awesome
12:21	justin_smith	sdegutis: it would be nice if instead the thing that attached metadata was a separate composible function
12:21	justin_smith	so instead of making a var just for the side effect of getting the metadata we want, we could pull that metadata-generator in
12:21	justin_smith	kind of like how destructure is just a function you can call in your macro if you want it
12:22	sdegutis	justin_smith: that would be impossible tho unless your fn was quoted
12:22	sdegutis	unless..
12:23	justin_smith	sdegutis: look at the source to defn, most of the code is just building the metadata map
12:23	justin_smith	sdegutis: if that happened in a separate function, we could use it
12:23	TimMc	open a jira ;-)
12:23	justin_smith	TimMc: seriously considering it!
12:24	sdegutis	justin_smith: i feel 100% confident everyone will be against the idea
12:24	justin_smith	sdegutis: oh I know it, but it's the principle of the thing!
12:25	sdegutis	justin_smith: ok well if you post it then link me ill +1 it
12:25	sdegutis	although itll probably be canceled out by amalloy's -1'ing it
12:26	justin_smith	sdegutis: he has a bot that just -1s anything you +1
12:29	Bronsa	caveat is that it'll only do that on bad ideas
12:32	sdegutis	Bronsa: like he said
12:39	sdegutis	I like how nicely assoc works with defrecord.
12:39	sdegutis	Nice job guys.
12:47	sdegutis	Why is this?
12:47	sdegutis	,(do (definterface Bar) (defrecord Foo [quux] Bar) ((juxt identity type) (dissoc (Foo. 2) :quux)))
12:47	clojurebot	[{} clojure.lang.PersistentArrayMap]
12:47	sdegutis	That's unexpected to me. I'd assume it would try to retain the type.
12:48	sdegutis	Even this:
12:48	sdegutis	,(do (definterface Bar) (defrecord Foo [quux zappa] Bar) ((juxt identity type) (dissoc (Foo. 2 3) :quux)))
12:48	clojurebot	[{:zappa 3} clojure.lang.PersistentArrayMap]
12:48	TimMc	When you remove a basis key on a record, it stops being a record.
12:49	justin_smith	sdegutis: yeah, that's been the expected behavior for a while now - I'm thinking at least since 1.5? maybe before that even?
12:49	sdegutis	Is that desired behavior?
12:49	TimMc	"expected"
12:49	justin_smith	definitely explicit - I remember it changing
12:49	Bronsa	Bar is completely useless to your example
12:49	sdegutis	Yeah I carefully avoided using the word "expected" in my last question.
12:49	sdegutis	It has disparity with assoc:
12:50	Bronsa	justin_smith: I think that's actually always been the case, not a 1.5 change
12:50	sdegutis	,(do (definterface Bar) (defrecord Foo [quux] Bar) ((juxt identity type) (assoc (Foo. 2) :quux nil)))
12:50	clojurebot	[#sandbox.Foo{:quux nil} sandbox.Foo]
12:50	Bronsa	sdegutis: rationale is that by being X + something else you're still X, by being X - parts of X you're no longer X
12:50	sdegutis	Bronsa: hmm I can see that
12:51	sdegutis	still, it feels wrong
12:51	Bronsa	some would argue not behaving this way feels wrong
12:51	TimMc	Where it gets gross is when you want to break apart a map and reconstruct it.
12:51	TimMc	(into (empty m) (for [[k v] m] ...)) works great to preserve type for most maps, but not for records
12:51	Bronsa	where it gets gross is when (empty some-record) throws but (dissoc some-record record-key) doesn't
12:52	justin_smith	(assoc instance :field :temporarily/removed)
12:52	justin_smith	haha
12:52	TimMc	Aw man, empty throws on records? Didn't know that.
12:52	Bronsa	yeah
12:52	TimMc	yuck yuck yuck
12:52	Bronsa	it feels really wrong that empty doesn't behave like reduce dissoc (keys record)
12:52	sdegutis	TimMc: that makes more sense though, because you're reconstructing a map from only the fields of a record, without "re-attaching" the metadata
12:53	sdegutis	TimMc: whereas dissoc seems more like removing a field while preserving the rest of the thing
12:53	Bronsa	I'd rather have either both dissoc/empty throw or have them both fallback on normal maps
12:53	Bronsa	there's no good reason why (defrecord X []) (empty (X.)) shouldn't work
12:53	sdegutis	naturally its far too late to make any changes like that since it would break every clojure app ever
12:54	Bronsa	Don't think so
12:54	Bronsa	if something hasn't worked, making it work shouldn't break anything
12:55	Bronsa	and if you're depending on (f x) throwing an UnsupportedOperationException, your code deserves to be broken
12:55	justin_smith	Bronsa: unless someone was intentionally throwing errors as flow control, and if they did that, they deserve broken code.
12:55	justin_smith	right, right
12:55	Bronsa	justin_smith: they deserve more than that
12:55	Bronsa	unless they're doing that as an optimization :P
12:56	Bronsa	but in that case, you're still not going to throw an UOE
12:56	Bronsa	justin_smith: IIRC core.match uses exceptions as flow control for non-local returns
12:57	justin_smith	ick
12:57	sdegutis	Bronsa: you planning to file a jira ticket?
12:57	Bronsa	no
12:57	sdegutis	ok i might then
12:57	Bronsa	justin_smith: it's surprisingly fast
12:57	justin_smith	Bronsa: I'm sure it was a perf improvement over the sane option, but still, ick
12:58	Bronsa	justin_smith: you're either going to use recursion or exceptions if you want to backtrack in clojure
12:58	Bronsa	since there's no goto
12:58	Bronsa	or explicit return
12:58	Bronsa	(both or which exist in java)
12:59	Bronsa	(both of which are incredibly useful for this kind of stuff)
12:59	justin_smith	that's true
13:00	justin_smith	and also sad, it would be nice to have a cleaner thing like continuations
13:00	Bronsa	¯_(ツ)_/¯
13:00	Bronsa	I honestly don't think continuations are much cleaner thatn gotos
13:00	Bronsa	than*
13:01	justin_smith	well, they are first class, but I guess it's not so hard to make a goto first class and juggle lexical environments to go with them...
13:03	sdegutis	Bronsa: what about the continuation monad?
13:19	gfredericks	if you were using test.check's recursive generator
13:20	gfredericks	(gen/recursive-gen some-collection-generator-fn some-scalar-generator)
13:20	gfredericks	would you expect it to ever generate pure scalars, or only collections of varying depths?
13:23	gfredericks	also does anybody use freenode from erc and how can I get past that weird auth thing it does now.
13:25	hiredman	gfredericks: well, only generating collections of various depths would make it weird that you passed in a scalar generator
13:25	gfredericks	hiredman: I mean for (gen/recursive-gen gen/vector gen/boolean), it could generate [true [false false]] but never true or false
13:25	hiredman	right
13:25	gfredericks	so the scalar generator does get used either way
13:26	hiredman	if you are have a tree generator, would you ever generate just a leaf
13:26	gfredericks	yeah, same question
13:27	gfredericks	I'm hoping there'll be a compelling example of some sort :)
13:27	gfredericks	I think it's relatively easier to get one from the other
13:27	gfredericks	s/easier/easy/
13:28	gfredericks	http://dev.clojure.org/jira/browse/TCHECK-83
13:28	gfredericks	I think I created this when I was making a json generator and got surprised when it didn't generate any scalars; but on the other hand in some json contexts pure scalars are considered invalid I think
13:29	hiredman	if you where testing some kind of recursive tree traversal, depending on the traversal code, you might want to test hitting a leaf
13:32	hiredman	although, if you are thinking of it as a tree kind of data structure, a lot of those have lots of rules associated with their structure, so you can't just generate them recursively willy nilly
13:33	gfredericks	rules that are only valid at the root in particular?
13:34	gfredericks	it might make sense to restrict this to use cases where you can generate things recursively willy nilly
13:34	gfredericks	given the signature of the function
13:36	hiredman	a tree structure I might want to test would be, I dunno, a red black tree, but those have rules about what nodes can be children of other nodes, and are restricture to two children per node
13:36	hiredman	yeah, only things willy nilly
13:36	gfredericks	yeah, I think that would require something more general/customizable
13:36	hiredman	so like json or edn
13:36	gfredericks	right
13:37	gfredericks	speaking of trees it is Bronsa
13:37	hiredman	an edn generator I would definitely expect to hit leaves
13:38	gfredericks	you could also argue that including leaves is better for test.check uses in particular to avoid accidentally undertesting
13:38	gfredericks	I think adapting it to not do leaves is as simple as calling (collection-gen-fn (gen/recursive-gen collection-gen-fn scalar-gen))
13:42	gfredericks	okay I'm convinced
13:42	gfredericks	everybody brace for minor breaking changes
13:42	hiredman	a clojure code generator that did included generating type hints would be nice
13:42	gfredericks	is that related?
13:43	hiredman	not really
13:43	gfredericks	okay cool just checking
13:43	gfredericks	thought I was missing something
13:43	gfredericks	has somebody written a general code generator somewhere?
13:47	amalloy	justin_smith: never fear, your has-arity? is in fact not correct
13:47	justin_smith	amalloy: awesome, what's the mistake?
13:48	amalloy	try it on (fn [] (inc 1 2 3 4))
13:48	amalloy	it'll claim not to have arity 0, but of course the problem is that in lacks arity 4
13:48	justin_smith	oh, of course
13:48	justin_smith	cool, I feel much better now
13:49	sdegutis	Some aspects of Component really confuse me. Is this normal?
13:49	amalloy	it's the same reason you get bogus errors for stuff like (defmacro fo [] (inc 1 2 3 4))
13:49	amalloy	,(defmacro foo [] (inc 1 2 3 4))
13:49	clojurebot	#error {\n :cause "Wrong number of args (4) passed to: core/inc--inliner--4489"\n :via\n [{:type clojure.lang.Compiler$CompilerException\n :message "clojure.lang.ArityException: Wrong number of args (4) passed to: core/inc--inliner--4489, compiling:(NO_SOURCE_PATH:0:0)"\n :at [clojure.lang.Compiler analyzeSeq "Compiler.java" 6875]}\n {:type clojure.lang.ArityException\n :message "Wrong numb...
13:50	amalloy	well, apparently inc is smarter now
13:50	amalloy	,(defmacro foo [] (seq 1 2 3 4))
13:50	clojurebot	#'sandbox/foo
13:50	amalloy	,(foo)
13:50	clojurebot	#error {\n :cause "Wrong number of args (2) passed to: core/seq--4357"\n :via\n [{:type clojure.lang.ArityException\n :message "Wrong number of args (2) passed to: core/seq--4357"\n :at [clojure.lang.Compiler macroexpand1 "Compiler.java" 6781]}]\n :trace\n [[clojure.lang.Compiler macroexpand1 "Compiler.java" 6781]\n [clojure.lang.Compiler macroexpand "Compiler.java" 6837]\n [clojure.lang.Com...
13:50	justin_smith	haha
13:50	amalloy	,(defmacro foo [] (seq))
13:50	clojurebot	#'sandbox/foo
13:50	amalloy	,(foo)
13:50	clojurebot	#error {\n :cause "Wrong number of args (-2) passed to: core/seq--4357"\n :via\n [{:type clojure.lang.ArityException\n :message "Wrong number of args (-2) passed to: core/seq--4357"\n :at [clojure.lang.Compiler macroexpand1 "Compiler.java" 6781]}]\n :trace\n [[clojure.lang.Compiler macroexpand1 "Compiler.java" 6781]\n [clojure.lang.Compiler macroexpand "Compiler.java" 6837]\n [clojure.lang.C...
13:52	gfredericks	I got to write a function called random-psuedofactoring: https://www.refheap.com/115236
13:53	cfleming	{blake} TEttinger3: Sorry for the problems. I haven't had time to reproduce with that project.clj yet, but generally you have to add the deps to the project.clj, and then use the Refresh Leiningen Projects action, which you can either search for or use the lein toolwindow.
13:54	amalloy	gfredericks: returns, not generates? that makes it sound to me like it just keeps one collection lying around forever, and always gives that one
13:54	{blake}	cfleming: I did not know there was a lein toolwindow! Cool!
13:54	gfredericks	amalloy: well it's in the context of test.check generators, so hopefully that means the more natural interpretation is that it doesn't return a generator
13:54	gfredericks	but that there might be a better wording
13:55	gfredericks	I think a lot of docstrings for functions that return generators just say "Generates ..."
13:55	amalloy	it seems like this could be a generator if you wanted it to, right? am i wrong, or is there a reason not to do that?
13:56	gfredericks	amalloy: yeah it could be one that's just not what I needed it for
13:57	sdegutis	im back
13:57	amalloy	i understand you owe me a link to something so i can downvote it, sdegutis
13:57	sdegutis	amalloy: oh yeah hold on
13:57	sdegutis	amalloy: https://gist.github.com/sdegutis/62f0b4177f01cf331218
13:58	sdegutis	amalloy: its not yet turned into a mailing list discussion but justin_smith had toyed around with the idea of extracting the metadata-generating code from defn and turning it into a stand-alone function (which defn then uses) so it can be used independently similar to how 'destructure' works
13:58	sdegutis	amalloy: anyway please downvote my gist
13:59	amalloy	oh. you mean like clojure.tools.macro.name)with-attributes?
13:59	sdegutis	amalloy: justin_smith /cc
13:59	sdegutis	amalloy: not quite, cuz fn+ here generates :arglists for you
14:00	sdegutis	amalloy: that was the main reason i invented fn+ today
14:01	amalloy	well, it's a cute trick anyway
14:02	sdegutis	thanks!
14:02	amalloy	github doesn't have downvotes, so i forked and deleted it
14:02	sdegutis	amalloy: haha or yu could comment with -1
14:02	sdegutis	:-1: technically
14:03	sdegutis	wow u wasnt kiddin https://gist.github.com/amalloy/05b64a9418fd318b7916/revisions
14:04	sdegutis	amalloy: actually your revision should just contain `(meta (fn [x] (inc x)))` so its made clear that your fork results in less functionality than the thing you forked
14:04	sdegutis	:D
14:06	justin_smith	amalloy: my thought was that it would be nice to be able to generate the same metadata properties that defn would, or that def would, without having to call def/defn, so the specific metadata generation could be refactored into a function - name-with-attributes is nice but doesn't do all the metadata defn does, and would need to be manually updated for each change to core's defn
14:08	sdegutis	justin_smith: what would such an api look like in action?
14:09	sdegutis	justin_smith: (let [f (fn [])] (generate-metadata f)) ?
14:09	sdegutis	justin_smith: or (generate-metadata (fn [])) ?
14:11	justin_smith	sdegutis: maybe something like (defmacro fn+ [& body] `(with-meta (fn ~@body) ~(gen-meta body)))
14:11	justin_smith	sdegutis: but I realized the annoying thing about making a function that defn would use to generate its macro - you can't use defn to define that helper :)
14:13	amalloy	or syntax-quote
14:13	justin_smith	amalloy: oh yes, of course
14:14	justin_smith	that would also be an annoyance
14:16	{blake}	I have a vector of vectors I'm using to make my web-page, and now (using React) I have to update a value in that vector of vectors.
14:17	{blake}	[[{stuff}{stuff}{stuff :control {:cell-name "target" :value "changethis"}}][next row...]]
14:18	justin_smith	{blake}: are you using react directly or with some clojurescript wrapper?
14:18	{blake}	justin_smith: reagent
14:18	amalloy	don't use vectors to store stuff you want to look up indexed by some key
14:18	justin_smith	{blake}: don't change the vector, use a function call to generate the vector
14:18	{blake}	amalloy: Well, I didn't know I was going to have to.
14:18	amalloy	instead of searching through a bunch of vectors, wouldn't it be lovely to have a map? {"target" ...}
14:19	justin_smith	amalloy: this is hiccup
14:19	justin_smith	so generate the hiccup, instead of using a literal
14:19	amalloy	if it were hiccup you would have a seq of vectors, perhaps. never a vector of vectors
14:19	justin_smith	{blake}: or do you mean some source data? if so, yeah do what amalloy says
14:19	{blake}	OK, so, yeah, I've thought of "change it to a map" and "regenerate the vector". Just seems like a lot of work.
14:20	justin_smith	{blake}: less work than arbitrary updates in a vector I'd think
14:21	{blake}	So, the deal is, my server sends me data that I used to make an entry page for the user, including pre-populating some of those values.
14:21	{blake}	(At the user's request.)
14:21	{blake}	I'd been putting those in "defaultValue".
14:21	{blake}	Only to discover that reagent only uses defaultValue first time out.
14:21	{blake}	When the component is first rendered. So I put it in value.
14:22	{blake}	But if I put it in value, all my components gotta be "controlled".
14:22	{blake}	And to make them "controlled", I gotta be able to update that structure the server sends.
14:22	{blake}	So.
14:22	{blake}	Crap.
14:24	justin_smith	{blake}: send the data from the server in a form you can easily access, and generate the structure you need on the frontend from that
14:25	justin_smith	so yeah, a map instead of vector, like amalloy said
14:25	{blake}	Or...
14:25	{blake}	Maybe send two structures. Since the only thing that's going to change is a small subset of controls->values, keep one for the structure of the whole page, and a little part for the react stuff.
14:26	justin_smith	but it's easier to generate the right vector from a map than it is to update a vector correctly
14:26	justin_smith	if you need a vector, make it out of maps
14:28	rhg135	Juxt is useful for that
14:28	justin_smith	indeed!
14:31	gfredericks	~juxt
14:31	clojurebot	juxt is usually the right answer
14:31	gfredericks	~juxt
14:31	clojurebot	juxt is a little hard to grok but it's the best thing ever
14:31	gfredericks	~juxt
14:31	clojurebot	juxt is usually the right answer
14:32	{blake}	Lotta juxt propaganda goin' on.
14:32	tcrayford_____	juxt shut up already
14:34	{blake}	I have a nice thing on the server where it's going through the cells of the spreadsheet and creating a vector.
14:35	{blake}	A vector of vectors. Rows and columns. Then I just go through this on the client side, same way.
14:35	{blake}	I guess I could key it as [col row] and make a flat map.
14:35	sdegutis	just and comp are cool
14:36	sdegutis	just don't expect them to notice rebound vars unless you explicitly pass vars
14:36	sdegutis	(comp foo/bar foo/quux) ;; redefine #'foo/bar or #'foo/quux and it will never notice
14:36	sdegutis	(comp #'foo/bar #'foo/quux) ;; this will though
14:36	sdegutis	This works because you can call vars as functions if you try hard enough.
15:04	sdegutis	Hello.
15:04	sdegutis	What's your recommended way of sharing many common immutable parameters between a group of functions?
15:05	sdegutis	The way I'm currently using is to have each of them take a map as its first parameter with each of these values at common keys.
15:50	rhg135	But then you can't compose them elegantly, I guess it's not as bad
16:25	justin_smith	clearly what we need is some crazy hack using metadata to imitate monads
16:25	justin_smith	(that was in response to rhg135 but it's universally true as well, of course)
16:56	{blake}	Who doesn't love crazy hacks?
16:56	justin_smith	in fact I sometimes suspect I am a crazy hack
16:58	amalloy	isn't using metadata to imitate monads like using...noodle soup to imitate 4chan? they are just totally disjoint separate things
16:59	CaptainLex_	Well that's what makes the hack /crazy/
17:00	justin_smith	amalloy: in the sense that a monad can track a separate immutable value implicitly carried forward in each call, which could hackily be a metadata passed along on values
17:00	justin_smith	or maybe I'm just talking nonsense again
17:15	rhg135	justin_smith: I just pass everything in one mega map, maybe a magic monad is better
17:21	gfredericks	oh man; I have a memory perf test in test.check that runs fine on the jvm but blows the stack (?) in cljs
17:21	gfredericks	#object[RangeError RangeError: Maximum call stack size exceeded]
17:22	gfredericks	I guess either nodejs has a smaller default stack than the jvm or cljs uses more stack frames than clj or both?
17:27	CaptainLex_	gfredericks: The former wouldn't surprise me one bit
17:28	gfredericks	this shouldn't even be a particularly stacky usage :/
17:28	gfredericks	still trying to get a proper stack trace
17:30	gfredericks	the internet says that e.stack is something useful but for me it's undefined :/
17:30	gfredericks	so I'm not sure how to figure out what's so stacky about this
18:04	rhg135	that would be the reader monad now that I think it
18:45	srruby	I want to do something like: lein ring server -env=testing To indicate that the server is running in a testing environment. Thanks, John
18:46	CaptainLex_	srruby: I don't know about any special ring stuff, but can't you just pass environment variables to the JVM like normal?
18:46	CaptainLex_	Which I don't have any real experience with either
18:53	srruby	CaptainLex_ : I guess I'll use (export FOO=bar; lein ring server)
18:54	CaptainLex_	Or you could ($FOO=bar lein ring server) if you didn't want to mess with your normal environment
18:54	CaptainLex_	Or you could even write a shell script to launch lein with the variables set according to arguments, if the syntax annoyed you
19:17	srruby	How can I change a string into a "reader" object ?
19:19	CaptainLex_	srruby: What are you trying to do?
19:20	srruby	CaptainLex: I have some code that reads from a file and processes the data. I want to test the code with a string.
19:21	amalloy	with-in-str
19:21	srruby	Something like new Reader(new stringBuffer("test data")
19:21	srruby	amalloy: Thanks
19:25	srruby	O
19:44	srruby	OK. This is what I came up with.
19:44	srruby	(defn reader-from-string[s]
19:44	srruby	(new java.io.BufferedReader (new java.io.InputStreamReader (new java.io.ByteArrayInputStream (.getBytes s)))))
19:44	srruby	(slurp (reader-from-string "a,b,c,d"))
19:45	srruby	seems clumsy
19:46	rhg135	StringReader exists
19:50	srruby	OK. This works. (with-in-str "hello" (parse-data (clojure.java.io/reader in)))
19:50	srruby	That is what I was looking for.
19:53	srruby	(parse-data (new java.io.StringReader "a,b,c,d")))
19:54	srruby	rhg135: Thanks. (new java.io.StringReader "foo") was what I was looking for.
19:54	rhg135	np
19:55	amalloy	was there something wrong with (with-in-str "a,b,c,d" (parse-data in))?
19:56	rhg135	,(class in)
19:56	clojurebot	clojure.lang.LineNumberingPushbackReader
19:56	rhg135	oh
19:57	amalloy	,(with-in-str "a,b,c,d" (class in))
19:57	clojurebot	clojure.lang.LineNumberingPushbackReader
19:58	rhg135	I assumed it'd be a inputstream given his code
20:01	amalloy	,(class System/in)
20:01	clojurebot	java.io.BufferedInputStream
20:01	rhg135	hmm
20:45	n0n3such	hey
22:22	hodwik	Are LISPs hard to read because I'm not used to them, or are they just harder to read?
22:23	tolstoy	I find them easier to read, but I suspect Clojure's use of brackets, and syntax highlighting improve that significantly.
22:25	hodwik	I guess I find it easier to get a sense of what the code is doing at a fine-grained level
22:25	hodwik	but I'm having a hard time stepping back and seeing the big picture
22:25	hodwik	because all of the pieces are so low-level logically
22:26	tolstoy	Coming from Java?
22:26	hodwik	Python & Java
22:28	tolstoy	A friend just went through a similar thing. For him, realizing that the functions were verbs seems to have helped a lot (his words not mine).
22:30	hodwik	Hmm, I'm not sure I follow.
22:31	tolstoy	Clojure functions, generally, take data as parameters and transform it into another form of data.
22:31	tolstoy	So, map, reduce, filter, etc.
22:31	tolstoy	So, just read the function names and get a sense of what they're doing.
22:33	hodwik	I've gotten that far
22:33	hodwik	I'm just not sure how to skim code, so to speak
22:33	hodwik	to get the big ideas
22:33	hodwik	Everything looks equally important, in a way
22:34	TEttinger	ah, yeah. an interesting thing is that what would be a few lines in java, with a for loop for instance, is typically a one-line call in clojure to a collection-based fn
22:35	hodwik	So then maybe skimming code is not the right strategy to read code in clojure?
22:35	TEttinger	like map vs. creating a new ArrayList and appending to it in a for(Thing thing : myList) {} way
22:35	tolstoy	That's what I do.
22:35	TEttinger	clojure code tends to be slightly wider and much less vertically stretched
22:35	tolstoy	But I skim by first reading the names and then maybe glancing at the function body to see if there's filter, reduce, map, or something.
22:36	TEttinger	yeah, similar here
22:36	tolstoy	Like this: https://github.com/ring-clojure/ring/blob/master/ring-core/src/ring/middleware/params.clj
22:36	tolstoy	I start at the bottom and go up.
22:37	hodwik	Interesting, why read from the bottom?
22:37	tolstoy	That's usually where the "main" function is, with all the ones above it in support position.
22:38	TEttinger	it is a big benefit to know if you're dealing with a many-to-many fn (map and mapcat are commonly used like this, filter usually), a many-to-one (usually reduce, not always), a one-to-many (iterate, certain uses of loop, for can be used something like this), etc.
22:38	tolstoy	Then I quickly scan up and see, assoc-query-params, where I can see he's parsing the querystring from the request (:query-string this or that).
22:39	tolstoy	I can see that he's parsing the query string into a key/value and associating it to the request as two keys. The rest the functions: shrug.
22:40	tolstoy	Keywords are pretty nice because you can kinda trace the transformation of data by scanning for them.
22:40	hodwik	Oh, that
22:41	hodwik	's an interesting strategy.
22:41	tolstoy	I didn't know I had that strategy until looking at that code. ;)
22:44	hodwik	Do you find yourself using other people
22:44	hodwik	's code/libs less when writing in Clojure?
22:45	tolstoy	Sort of.
22:45	tolstoy	For me, the biggest difference between Clojure and your avg Java/Python/C# approaches is the separation of data from functions.
22:46	tolstoy	For instance, with that "ring" web stuff, you realize that it's just a wide variety of functions that take a "request" map and produce a "response" map (mainly).
22:47	tolstoy	Once you get that, you can skim the code if, say, you wonder how it handles cookies, or query strings, or a response with a body of type "stream".
22:47	tolstoy	So, the "big idea" you mentioned is getting that main idea, the request map.
22:49	tolstoy	And given that the vast bulk of Clojure code is just maps and lists, you don't need to look for type names (like domain objects).
22:50	tolstoy	So, you don't look for things like User, but, instead, for functions that seem to operate on users, like, (auth? user) or (valid? db-conn email password) and so on.
22:50	tolstoy	So, yeah, from the point of view of OO, it can seem like undifferentiated soup. ;)
22:53	hodwik	So with Python and Java, I find Python much more expressive. However, I also find it much more difficult to read my code 6 months later than with Java. As if, all that boilerplate just acts as a visual cue.
22:53	hodwik	My concern is that Clojure is going to go farther in that direction.
22:54	hodwik	I take it that you do not experience that relationship between expressiveness and readibility, if you find clojure to be more readable?
22:56	tolstoy	Clojure's the first language where, when I didn't understand a docstring, I clicked the "show source" link and that actually helped.
22:57	tolstoy	I do find it more readable, I think, because everything's in one place. With Java, I have to use Intellij so I can bop around because any given thing seems to involve dozens of objects.
23:02	hodwik	I was thinking it'd be pretty cool to have syntax highlighting that does every pair of parens a different color. Does such a thing exist?
23:03	tolstoy	rainbox delimiters
23:03	tolstoy	rainbow, sorry.
23:03	hodwik	Awesome. Is it useful/popular?
23:04	tolstoy	I think it's reasonably popular. What's your editor?
23:05	hodwik	Well, I've got Emacs setup, but I wouldn't call it my editor, but that's where I'm working on Clojure right now.
23:06	tolstoy	https://github.com/Fanael/rainbow-delimiters
23:06	tolstoy	Alas, no pictures on that page.
23:07	hodwik	Thanks
23:07	hodwik	I'm checking out some screenshots, it looks a bit more distracting than I thought it would
23:08	tolstoy	I find it so.
23:08	amalloy	hodwik: ideally you should be paying attention to the indentation, not the parens
23:08	hodwik	Is focusing on the parens the wrong way to go about it. That is, do you read the "verbs" more than the parens?
23:08	tolstoy	Yeah, I dim my parens, actually.
23:08	tolstoy	And use paredit to manage them.
23:08	amalloy	parens are for the computer
23:09	tolstoy	Anyone happen to know how to query specific network adapters via command line on windows?
23:09	hodwik	Ah, I think stanislav datskovskiy told me that
23:09	hodwik	I had forgotten
23:24	macrolicious	I'm getting a FileNotFoundException: Could not locate seesaw/core__init.class or seesaw/core.clj on classpath in spite of having :dependencies [[org.clojure/clojure "1.5.1"]
23:25	hiredman	seesaw is not part of clojure
23:25	hiredman	so saying you depend on clojure doesn't mean you get seesaw
23:51	totalnes`	hiredman: oops, I meant to say I had: :dependencies [[org.clojure/clojure "1.5.1"] [seesaw "1.4.4"]])
23:51	totalnes`	last line didn't paste
23:51	totalnes`	in my src directory I have seesaw.
23:58	hiredman	totalnes`: what do you mean by "in my src directory I have seesaw." ?
23:59	hiredman	in the interest of short circuiting this, you likely added the dep to project.clj and didn't restart your repl