#clojure – 2017-06-26

2017-06-26

03:25	dysfun	i'm starting to think spec would be better if they just gave up on predicates as being the basic thing and moved to conformers being the basic thing
04:31	Rovanion	dysfun: And if a conformer gives a truthy value the input is valid?
04:31	dysfun	if a conformer returns something other than ::s/invalid, it is valid
04:32	dysfun	under the hood, everything is based on conformers
04:32	Rovanion	Sounds better.
04:32	dysfun	i'm left thinking it was a mistake to make predicates the basis of declaration
04:33	dysfun	predicates can be trivially wrapped to conformer-ise them
04:34	Rovanion	I can imagine that the reason why its not already is because conformers (I imagine) are slower than predicates. But you always want your sequential data structures to be reformed as tagged such or maps?
04:34	dysfun	but under the hood it uses conformers
04:34	dysfun	when you call s/valid? that is a call to conform and checking it didn't return ::s/invalid
04:38	Rovanion	You're absolutely correct. That is strange.
04:38	dysfun	i know i'm correct, i've spent the last few days trying to understand spec's internals because i'm writing another library for it
05:13	osfabibisi	ooo, you can use `conj` as a confusing synonym for `merge`
05:13	dysfun	o_O
05:13	ridcully_	"here is my conj request"
05:13	dysfun	,(conj {:a :b} {:c :d})
05:13	clojurebot	{:a :b, :c :d}
05:46	dysfun	anyway, clearly the correct terminology is 'rebase request'
05:48	Rovanion	I request that you rebase your code on mine!
07:57	dysfun	https://gist.github.com/jjl/67658ccfff52a9cfb5b82f124bb2c82e # thoughts?
07:58	dysfun	(mainly from spec users)
07:58	dysfun	not finished, obviously
08:12	osfabibisi	some of your indentation is broken
08:12	osfabibisi	in the :require
08:13	osfabibisi	looks like a nice approach
09:00	dysfun	thanks
09:00	dysfun	it's changed considerably since i started it
11:54	assoc-in`	DOes anyone know how to get the pretty printing like (clojure.pprint/pprint map) to output to a log file using timbre?
12:07	justin_smith	assoc-in: I'm not sure if there's anything pre-rolled, but you could make your own macro using (with-out-str (pprint m)) inside a log macro
12:21	assoc-in	justin_smith: awesome that worked perfectly. I hadn't heard of with-out-str before
12:22	justin_smith	one thing to look out for is that with-out-str exposes how printing is a side effect - if anything inside your call prints, it will become part of the generated string
12:22	justin_smith	which can bite you if you try to println debug
15:01	hellofunk	the first item in the seq returned by this statement has both elements of the vector equal: (for [x (range 3) y (range 3)] [ x y])
15:01	hellofunk	so what i don't understand is why this variant with the :while doesn't short circuit immediately:
15:01	hellofunk	(for [x (range 3) y (range 3) :while (not= x y)] [ x y])
15:02	hellofunk	instead, it returns: ([1 0] [2 0] [2 1])
15:03	justin_smith	yeah, I've never really understood the behavior of the :while key to be honest
15:03	amalloy	:while only terminates the innermost loop
15:03	amalloy	so it gives up on finding any y fitting with x=0, and then starts over with x=1
15:04	hellofunk	oh, so :while can cause multiple inner loops to quit, rather htan the whole for expression to quit
15:05	justin_smith	amalloy: oh, now that I look at the docs, the inner-loop behavior is not explicitly described but it is evident in the output of the example given
15:05	hellofunk	if you had three loop parameters instead of my two, and the while did not address the value of the third parameter, hm... (goes to test that out)
15:06	amalloy	if :while always affected the expression as a whole, it would be no more useful than wrapping the expression with take-while
15:06	amalloy	by being more fine-grained it makes itself an actually useful operator
15:07	amalloy	(albeit one that sees little use)
15:11	hellofunk	why does this return the entire sequence i give it: (take-while #(not= % %2) [[0 1] [ 0 0] [ 3 4]])
15:13	ridcully_	that gives an error
15:13	ridcully_	you need some destructuring in your predicate
15:13	hellofunk	well, i'm running a cljs repl, so perhaps the behavior is different than clojure?
15:13	hellofunk	oh i see what you mean
15:13	justin_smith	oh yeah, cljs doesn't do arg length checks
15:13	amalloy	yes, javascript is comically relaxed about arglists
15:13	justin_smith	try #(apply not= %)
15:13	ridcully_	,(take-while (fn [[a b]] (not= a b)) [[0 1] [ 0 0] [ 3 4]])
15:13	clojurebot	([0 1])
15:14	hellofunk	gotcha
15:14	justin_smith	,(take-while #(apply not= %) [[0 1] [ 0 0] [ 3 4]])
15:14	clojurebot	([0 1])
15:15	hellofunk	how interesting that i can leave this channel for a couple years, come back and its the same guys giving out the same quality wisdom. almost like there is some consistency and stability in the universe
15:17	amalloy	#clojure favors immutability
15:19	Para`	Is produced advice a side effect, though?
15:20	Para`	It is an IO process, after all.
16:40	hellofunk	in reagent, a component is scheduled for a re-render if you deref an atom in a component function. is reagent smart enough to follow this if you call a function inside your component, and that other function does the deref?
16:42	random_numbers	An atom is being dereferenced, so I'd presume so.
16:42	random_numbers	I think the scoping works for you in that case.
16:42	hellofunk	scoping?
16:45	random_numbers	Probably the wrong terminology.
16:47	turbofail	hellofunk: all reagent cares about is whether the atom was dereferenced during the execution of the rendering function
16:47	hellofunk	turbofail: ok, so it doesn't matter where that happened, how many "levels deep" of nested function calls the deref occurred?
16:47	turbofail	hellofunk: yeah
16:47	turbofail	hellofunk: it also means it might not work for a deref that happens within a lazy sequence
16:48	turbofail	see https://github.com/reagent-project/reagent/issues/18
16:48	random_numbers	Interesting.
16:49	hellofunk	nice link, thanks
19:32	technomancy	what's up with people who put a newline before their arglist even if there's no docstring
19:33	xulfer	Heh don't know. I guess maybe they're planning on adding one later? :P
19:33	amalloy	regularity with functions that have docstrings, i assumed
19:33	xulfer	Though I would use a TODO for that if it were me
19:46	technomancy	I am having a hard time bringing myself to match that style for the functions I add =\
19:48	xulfer	Same, but mostly because I've been mostly doing literate clojure lately.
22:28	Seylerius	How do you compare the runtime of two chunks of clojure code?
22:30	Seylerius	Found it. Thanks.
22:31	Seylerius	Okay. Our test conditions in `cond2` take `8.290295 msecs`, while the same test in `cond` takes `0.628934 msecs`.
22:31	Seylerius	Whoops, wrong chan.
22:35	Seylerius	Okay. I'm trying to sell someone on macros. Can y'all give me your best "Couldn't do this without a macro" examples?
22:37	matthavener	Seylerius: core.async go blocks
22:38	matthavener	Seylerius: cond-> (without tons of anonymous fns)
22:38	Seylerius	Example, matthavener?
22:38	Seylerius	Ooh, that one looks great.
22:40	TimMc	technomancy: Why would you ever add a defn without a docstring? :-)
22:41	Seylerius	TimMc: Ah, shit, are docstrings build with macros?
22:42	TimMc	Seylerius: FSVO "build", yeah, but I was responding to a different thread of conversation.
22:42	Seylerius	Heh.