#clojure – 2016-02-06

2016-02-06

06:40	benjyz1	hello. I'm wrestling with SQL in Clojure
06:40	benjyz1	jdbc/insert! for some reason doesn't commit to my database
06:41	benjyz1	https://www.refheap.com/114533
06:42	benjyz1	do I need some kind of commit?
06:45	benjyz1	ok, nevermind, just some weird error
06:46	mmeix	(makedb) etc is commented out
06:46	mmeix	ah .. ok
09:29	thomasfuston	Are there recommended ways to build GUI applictions with clojure?
09:46	dysfun	thomasfuston: if by that you mean 'non-browser applications', it's not recommendable
09:46	CaptainLex	Hehe I was going to say
09:46	thomasfuston	hmm so its better to have a browserinterface? even to a local app?
09:47	dysfun	no, it's better to write the app in not-clojure
09:47	thomasfuston	ok, you saying clojure is best for webdevelopement
09:48	dysfun	i'm saying clojure is ideal for anything where startup time is not a primary requirement
09:48	dysfun	and that don't require you to write a gui
09:48	dysfun	unless it's a web one
09:49	dysfun	the reason for the gui thing is frankly what java offers is shit and because you're on the jvm your interop with C libraries is piss-poor at best
09:51	thomasfuston	well i thought i could do a little app in clojure for learning purposes (coming from python), and it should be crossplattform so thought why not clojure
09:51	dysfun	in practice, if you want a crossplatform gui application, you use qt
09:52	dysfun	i think the java bindings are pretty outdated last i checked
09:52	dysfun	and it causes all sorts of deployment issues
09:54	dysfun	for the cross platform gui client i've got to build in the next few months, we're being slightly more ambitious, separating all the non-gui stuff out into a c++ library with a c wrapper. you can link that against all OSes including mobile
09:54	dysfun	of course currently i'm building the web client... in clojure+clojurescript
09:55	dysfun	the server, well that's a clojure webservice
09:56	dysfun	honestly i'm finding it easier to build for the web than build the clients, significantly so
10:10	CaptainLex	dysfun: What about using other Clojure targets, like PyClojure? Do those projects still have any momentum?
10:31	rhg135	I'm building a small gui app in clojure. Clojure starts fast enough and when you need fs io, it's easier and faster than cljs
10:32	dysfun	CaptainLex: i'm not convinced they're going anywhere
10:33	dysfun	i've personally got an llvm-clojure project on the back burner
10:33	CaptainLex	dysfun: True, but for thomasfuston's purposes - building a GUI app just to get his hands dirty - it might be useful.
10:34	dysfun	or, y'know, he could use python, which is a more suited tool for his purpose and he happens to know
11:18	arkh	or, y'know, it could be a fun project to learn more clojure
11:19	ridcully	never
12:41	benjyz1	hello. I'm working on a webapp with Clojure and Clojurescript. Ring delivers JSON with middleware, but I can't get the client to read it correctly
12:44	benjyz1	https://www.refheap.com/114540
12:44	justin_smith	benjyz1: the input to the handler won't be js, so js->cljs doesn't help
12:45	justin_smith	benjyz1: you need to use js/JSON to turn the string into js data
12:45	justin_smith	because it will just be a string
12:45	justin_smith	(or you can use whichever cljs wrapper for js/JSON you like of course)
12:54	benjyz1	thanks. trying with "(js/JSON.parse response)"
12:56	justin_smith	yeah, that sounds right
12:59	benjyz1	Unexpected string... when I try to parse {"foo" "bar"}
12:59	justin_smith	well that's not valid json
12:59	justin_smith	are you sending edn format?
12:59	justin_smith	in that case, you want cljs.reader/read-string or whatever it's called
13:00	justin_smith	or you could fix your middleware so you actually send json
13:01	benjyz1	I'm trying (wrap-json-response)
13:02	justin_smith	OK, are you setting the content-type header?
13:02	justin_smith	you might need to make sure your accept header is right on the client side too, I forget
13:06	benjyz1	I was looking around whether I can find a template which integrates ring and CLJS
13:11	macrolicious	does anyone know which rainbow delimiters mode works well in emacs -nw (in a terminall… iterm2 in my case)?
13:11	justin_smith	macrolicious: it should just be a question of adjusting the faces defined by rainbow-delimiters mode right?
13:12	macrolicious	ah ok… too noob to know that… sweet...
13:13	justin_smith	macrolicious: M-x customize-group<return>rainbow-delimeters<return>
13:14	justin_smith	then from there go to reainbow-delimiters-faces, and edit and preview to hearts content
13:15	justin_smith	macrolicious: it's also possible to customize these things outside of the customize interface, but customize is handy especially when new to emacs
13:16	macrolicious	that's really helpful… and I'll be able to pick the right faces...
13:47	kwladyka	What do you think about #_ in parameters (defn create-uuid! [uidable-id uidable-type type #_expired-in [n time-unit]]) <- is it good idea or should i use [exprired-in-n expired-in-time-unit] ? What is the standard?
13:48	kwladyka	i think send options is better
13:48	kwladyka	*second
13:49	kwladyka	maybe even like that (defn create-uuid! [uidable-id uidable-type type [expired-in_n expired-in_time-unit]]
13:49	justin_smith	why not (defn create-uuid! [uidable-id uidable-type type [n time-unit :as expired-in]] ...)
13:50	kwladyka	it is better, thanks!
13:52	djbkd	i'm starting Web Dev 2.0 book and can't seem to get through the first example...is ring broken on clj 1.7?
13:52	justin_smith	djbkd: the lein-ring plugin is broken with the latest lein
13:53	djbkd	ah ok
13:53	justin_smith	djbkd: if you "upgrade" to an older lein that fixes it
13:53	djbkd	hahaha
13:53	djbkd	so, like nodejs :c
13:53	djbkd	https://twitter.com/BadKittyDaddy/status/696041540896993280
13:53	justin_smith	hopefully the next ring will fix this :)
13:53	justin_smith	djbkd: sad timing for the new lein breakage, with that great book coming out...
13:54	djbkd	yeah i really like clj as a language
13:54	djbkd	but such is the nature of open source
13:54	kwladyka	Anybody from Switzerland here? I am wonder how looks Clojure work there.
13:54	djbkd	i'll try downgrading, thanks
14:02	macrolicious	justin_smith: got my delimiters all looking pretty… took a bit to figure out the customization interface, but yay!
14:02	RedNifre	If the clojure and leiningen versions in the ubuntu repository are very outdated, should I just extract the clojure zip somewhere and put a link named "clojure" in my ~/bin?
14:03	justin_smith	RedNifre: you don't need a zip
14:04	justin_smith	RedNifre: lein is a shell file
14:04	RedNifre	oh, so if I have lein I'm all set?
14:04	justin_smith	RedNifre: if you are using lein, lein finds and uses whichever version of clojure your project config tells it to
14:04	justin_smith	so yeah, if using lein, just the script suffices
14:04	RedNifre	I don't have a project config yet, I'm starting with clojure right now :)
14:05	RedNifre	okay, sounds good, I'll see how far I get...
14:05	justin_smith	RedNifre: though I do like keeping the latest clojure jar around for fiddling (faster startup time / simpler tooling as long as I don't need deps)
14:05	justin_smith	RedNifre: right, lein has a default clojure it will use, but once you create a project the project needs to declare a clojure version
14:06	justin_smith	RedNifre: if not using a project and therefore not having any deps, yeah, just use clojure.jar, use rlwrap too that makes it nicer
14:06	justin_smith	but pretty early on you will see the value of lein if you decide to use any deps outside clojure itself and the default jvm stuff
14:08	RedNifre	I have no opinions yet since I'm just starting out. The tutorial introduces lein and since I see the value of cabal/npm/gradle I'll probably like lein anyway.
14:08	dysfun	lein is my benchmark for build tools now
14:08	justin_smith	RedNifre: it is much better than the default usage of any of those, but cabal used properly is probably lein's equal :)
14:09	dysfun	but noone uses cabal properly, that's why we have stack :)
14:09	justin_smith	(properly meaning, no sharing of deps implicitly between projects, all things sandboxed but artifacts of same version shared via a cache)
14:09	dysfun	you know, you'd probably quite like stack
14:10	justin_smith	I'm sure, I'm still a n99b at haskell though
14:10	justin_smith	odometer hasn't even rolled over to n00b yet
14:10	dysfun	right, well even more reason to use stack. it's the best way to get started these days
14:10	justin_smith	cool
14:10	RedNifre	Possible, I heard about it peripherily. I also heard something about some cabal nix crossover thingy, does stack work well with nixOS as well?
14:11	dysfun	and the truth is that once you grok the syntax, just tweak monads until the type works and stop worrying about it
14:11	justin_smith	RedNifre: leiningen does with jvm deps something very close to what nix does to OS level deps (isolated subsets that are independent but sharing a cache of immutable versions)
14:11	dysfun	i'm not a nixos user, but loads of hackage has nixos builds
14:12	dysfun	besides, i'm too busy solving problems with haskell to be a haskell programmer
14:13	RedNifre	Unfortunately I haven't used Haskell in about a year :/
14:14	dysfun	justin_smith: https://github.com/jjl/ctaas/blob/master/src/Main.hs 53 lines in memory hashtable webservice
14:14	justin_smith	anyway, clojure's great, isn't that why we're all here?
14:14	RedNifre	maybe? :)
14:14	dysfun	haskell has a different useful niche
14:15	justin_smith	back when bytemyapp of "haskell from first principles" fame was a clojure programmer, we actually had to enforce a "no haskell before 7 pm" rule here
14:15	RedNifre	I'm currently working through various programming languages, Haskell is great but brutal, after that I tried node.js with coffeescript which was bad but highly productive. Now I'm looking at Clojure because it promises to be somewhat as tidy as Haskell, but also as productive as those messy languages.
14:16	dysfun	ah yeah, i pissed him off once by saying "fucking haskell programmers"
14:16	justin_smith	RedNifre: right, clojure is a great mix of tidy enough to be sane while pliable enough to do things quickly and refine later, imho
14:16	dysfun	clojure is my preferred tool when it's a good fit
14:17	RedNifre	That sounds a bit like a tautology.
14:17	justin_smith	dysfun: "x is my preferred too when it's a good fit" is a low information statement :)
14:17	dysfun	not really. it says "if clojure isn't disqualified, i'll pick it"
14:18	RedNifre	ah, you mean "if it isn't a bad fit"?
14:18	justin_smith	dysfun: oh, perhaps we understand "a good fit" differently
14:18	justin_smith	RedNifre: get out of my brain
14:18	justin_smith	bbl
14:20	RedNifre	dito
14:25	RedNifre	Oh no. What exactly happens when I do "lein run"? How much data does it download?
14:26	RedNifre	Ah dammit. The problem is that my internet connection is broken so I went to a place where there is internet, downloaded lein and a clojure zip and I'm now using my phone's exhausted connection. I guess lein now wants to download several MB of clojure, huh?
14:26	mmastic	I'm new but I think it would just get your dependencies and whatnot (which could even be the actual compiler). You can always just abort.
14:27	RedNifre	Well, I just started so I guess it's the compiler. It tried to download clojure 1.8.0, which failed because of networking issues. I have the clojure 1.8.0 zip file though. Can I somehow give that one to lein so it doesn't have to download it by itself?
14:28	justin_smith	RedNifre: I'd just use "rlwrap java -jar clojure-1.8.0.jar" for now
14:28	justin_smith	when you have a good connection, do the full deal
14:28	justin_smith	(with lein)
14:28	RedNifre	Hm, it says "if you are behind a proxy try setting the http environment variable". This might be the case because of my cellular provider. How do I set this variable and to what?
14:28	kwladyka	is any reason why "contains?" work only with one key...?
14:29	RedNifre	justin_smith what does that command do exactly?
14:29	justin_smith	RedNifre: starts a clojure repl
14:30	justin_smith	no other things available except the extensive libs offered by the vm itself
14:30	justin_smith	it's enough for a start, once you need deps, lein handles those nicely, but why fight to make lein work when your net is crap anyway?
14:30	lodin-	kwladyka: Huh?
14:31	justin_smith	lodin-: kwladyka wants (contains? m k1 k2 k3)
14:31	justin_smith	which doesn't work of course
14:31	kwladyka	lodin- exactly like justin_smith said
14:31	lodin-	And what would be true if m contained all keys?
14:31	justin_smith	I don't know why, I agree varargs would be nice
14:31	amalloy	justin_smith: i think varargs there would be bad
14:32	lodin-	s/what/that/
14:32	amalloy	because there are two reasonable meanings: (every? #(contains? m %) ks), or (some #(contains? m %) ks)
14:32	lodin-	Precisely, what amalloy said.
14:32	justin_smith	amalloy: I hadn't considered some being expected
14:33	noncom\|2	is anyone aware of a simple way to align a dava/joda time by 15 min-intervals? i.e. i want any arbitrary number of minutes to align to the nearest upper 15-minute quant?
14:33	noncom\|2	*java/joda
14:33	RedNifre	(if (contains? food :peanuts :seafish) (dont-eat food))
14:35	dysfun	obviously that's a too few parameters to if exception waiting to happen
14:36	lodin-	dysfun: Being sarcastic?
14:37	dysfun	well yes, but it is.
14:37	RedNifre	how so?
14:37	amalloy	dysfun: it's not
14:37	amalloy	,(if true 1)
14:37	clojurebot	1
14:38	dysfun	maybe it's just clojurescript that complains
14:38	justin_smith	dysfun: no, cljs doesn't complain
14:38	justin_smith	dysfun: maybe you are thinking of haskell
14:39	RedNifre	:D
14:39	dysfun	i'm really not. i've just spent two days fixing clojure to work under cljs
14:39	RedNifre	,(if false 1)
14:39	clojurebot	nil
14:39	lodin-	dysfun: Not that I would complain if it complained. The opposite, actually.
14:39	justin_smith	dysfun: I use single branch if all over my cljs code. This was a point of contention with another def (he didn't believe in ever using when), so I assure you cljs takes this without complaint.
14:40	justin_smith	*another dev
14:40	dysfun	well i can't explain the error messages i've received then
14:40	justin_smith	if he was a def I could have prevented him from going out of scope, but now we have to hire a guy
14:40	justin_smith	dysfun: perhaps it was too many args to if
14:40	dysfun	ah yeah, could be
14:40	RedNifre	What's a def and how does single branch if relate to not using when?
14:41	justin_smith	RedNifre: haha, I typod def for dev, as in coworker
14:41	dysfun	well a single branch if would act as a when, so the idea is not needed when
14:41	RedNifre	ah, missed the correction, now it makes sense :)
14:41	justin_smith	RedNifre: (when p? (f)) is the same as (if p? (f)), when is only different when it has more than one form
14:41	justin_smith	RedNifre: and my ex coworker hated when
14:42	dysfun	i quite like when
14:42	justin_smith	and would use single branch if instead, we argued about it
14:43	justin_smith	my argument for replacing single-branch if with when is that if I read when, I know I don't have to scan for a second form - I know all forms are used together if any are
14:43	justin_smith	so it's a reading comprehension gain
14:43	dysfun	agreed
14:43	RedNifre	I don't know enough about when to have an opinion on this yet. :)
14:44	dysfun	the truth is life is too short to really care
14:44	justin_smith	the opposing side is that "when is only for side effects since it accepts multiple forms" - I'll acknowledge reasonable devs can disagree on this, but the other side is wrong
14:44	RedNifre	horray, lein downloaded 1.8.0 and executed my example lein project and it outputted "Hello world!".
14:44	justin_smith	nice
14:45	dysfun	yeah, that's a good strategy for many tools
14:45	mmastic	Is there perhaps anyone here that came from Haskell?
14:46	dysfun	i came back to clojure after taking some time out to do haskell
14:46	justin_smith	RedNifre: once I had an error with some new deps while working in a cafe, so I deleted my m2 cache (where lein keeps all your deps) and tried to reset things. I have since learned that deleting the m2 cache is never actually needed except for the exact case I created then: the wifi in the cafe was giving me a small html file containing a click to agree and use the internet form instead of the jar files I was attempting to download
14:47	RedNifre	mmastic yes, me, sort of.
14:47	mmastic	Oh, I have and I'm trying to understand how API works here, especially with dynamic typing. Do you not check for types at all? I don't imagine it's idiomatic to assert the type of every single argument, right?
14:47	dysfun	justin_smith: well it would have failed its checksum then wouldn't it?
14:47	justin_smith	the result of this was a lot of things with names like "clojure.jar" and "ring-plugin.jar" etc. which all contained the same stupid snippet of html instead of clojure code :P
14:47	justin_smith	dysfun: hell, without a pom how would I get a checksum? the pom files contained html too
14:47	dysfun	mmastic: you tend to worry more about the shape of things than their type
14:48	dysfun	right, but it's never going to find the checksum matches, is it?
14:48	RedNifre	mmastic no idea, I'm on the first page of a clojure tutorial here.
14:48	justin_smith	mmastic: in practice we care much more about protocols and interfaces and multimethods. If something implements the right protocol or multimethod, the code should work
14:48	justin_smith	mmastic: usually this is implicit because we are using code whose primitives are all defined in terms of thse protocols and multimethods
14:49	RedNifre	Which brings me to REPL colors: The "brave" tutorial shows lein repl with some fancy colors which I don't see for some reason. Is there an easy fix (I probably don't need repl colors that badly but I wouldn't dismiss them if they were easy to enable).
14:49	justin_smith	but sometimes you get low level enough to need to define your own protocols / multimethods / interfaces, or extend them
14:49	mmastic	Oh I see, but is it idiomatic to use protocols and such? I figured it's preferred to keep it Lisp-y and only use protocols for Java interops.
14:49	dysfun	justin_smith: is that low level?
14:49	justin_smith	RedNifre: I am unaware of any actual repl color feature outside of maybe editor integration
14:50	justin_smith	mmastic: lists are a protocol
14:50	justin_smith	etc.
14:50	mmastic	dysfun: Are you referring to the collection abstractions?
14:50	dysfun	mmastic: protocols are useful for mimicking existing behaviour
14:50	justin_smith	mmastic: so it's lispy by using protocols :)
14:50	dysfun	yes
14:50	RedNifre	hm, maybe the tutorial just enabled syntax highlighting for every piece of clojure code which accidentally colored the repl listings there.
14:50	dysfun	it's basedo n what justin_smith is saying
14:51	RedNifre	Why is it called "-main" and not "main" or something like that?
14:51	mmastic	Yeah but it's not Lispy to define protocols for your data, right? it's all about maps, is that correct?
14:51	justin_smith	mmastic: the protocls and multimethods that most of clojure.core uses are extended very pervasively - you can get a seq from a string, an array, a list, a vector, a hash-map, ....
14:52	justin_smith	mmastic: so you don't need to type-check something you need a seq from - though seq will throw an error if it can't make a seq from the arg
14:52	dysfun	RedNifre: because main() is the java function. when you write :gen-class, it writes a wrapper main() function which sets up clojure and calls -main
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14:52	RedNifre	dysfun I see, thanks.
14:52	justin_smith	mmastic: lispy is that the only data structure you have is a list
14:52	lodin-	mmastic: I disagree with that. For pure containers, sure, no need to not to use a map, but for other values where you have invariants and such that you need to maintains I suggest defining your own interface (which may use a protocol).
14:52	justin_smith	mmastic: clojure extends that to "everything implements seq" (within reason)
14:52	justin_smith	via seq, we can treat everything as a list if needed
14:53	dysfun	when we say lispy in clojure, i think we mean more 'makes good use of builtins'
14:53	justin_smith	mmastic: and maps and lists are protocols, in clojure
14:53	justin_smith	so it's a false dichotomy
14:53	dysfun	"doesn't reinvent the wheel" perhaps
14:54	dysfun	or "knows when to reinvent the wheel" :)
14:54	justin_smith	mmastic: another way to put it is that in practice "everything is a list" and "every collection implements the protocol for lists" are pretty much the same when coding
14:55	mmastic	Ah I see. I'm pretty torn, I had figured they say that in Lisp/Clojure API is data and mean that. So if I have to enforce an invariant, map isn't a good choice anymore?
14:55	dysfun	yeah, for example you can treat a map as a list, it contains a vector of [key value]
14:55	RedNifre	Not sure if this is interesting to you clojure pros here, but I discovered this "parinfer" atom editor plugin which places parens based on indentation, which really helps people like me who aren't used to all these parens yet.
14:55	RedNifre	Basically, you indent the code like in python or haskell and the parens appear by themselves.
14:56	justin_smith	dysfun: mmastic: and that map -> ([k v] [k v]) transition maps directly to the idiom of alists in lisp
14:56	lodin-	mmastic: You can use a map, but you should probably not access the map directly, since the actual data representation may change. So provide functions to get the data that you want from it.
14:56	justin_smith	RedNifre: I look forward to using it when it's mature maybe, it looks like a cool concept
14:56	lodin-	mmastic: I can clarify that I think this mostly applies when you cross library boundaries.
14:56	justin_smith	lodin-: well, even "map" is a protocl, not a concrete data type
14:57	mmastic	And I assume a constructor function as-well, yeah?
14:57	justin_smith	mmastic: ?
14:57	RedNifre	Can anybody comment on emacs vs atom editor? I encountered atom first, but both editors seem to implement the same concept (powerful texteditor that you can customize with a simple language).
14:58	mmastic	justin_smith: Yup, I believe this is the case, however by map I just mean this kind of data-structure of pairs.
14:58	justin_smith	sure, right, and that's what that protocol means too
14:58	dysfun	if you like lisp, you'll like emacs.
14:59	dysfun	but the real advantage of emacs is that it's very fast to edit text when you've learned certain shortcuts
14:59	dysfun	and basically unusuable until you've learned the basics
15:01	mmastic	Thanks a lot for your help everyone; It's immensely appreciated.
15:01	RedNifre	Ah, so I reached the "when" part of the tutorial and unlike in my imagination, it is NOT like a switch statement; it's actually an else-less if, right?
15:01	justin_smith	right, and it accepts any number of forms
15:01	RedNifre	If "when" is an else-less if, why is the "else" part of an "if" optional?
15:01	justin_smith	so that must clarify the above quite a bit
15:02	justin_smith	RedNifre: "any number of forms"
15:02	dysfun	(when (foo) (bar)) ; returns result of (bar)
15:02	justin_smith	(when p? (fire missiles) (issue apology to mother) (say goodbye) (exit))
15:02	justin_smith	each action is done in turn - wouldn't work in an if
15:02	RedNifre	Yeah, I think I understand that. I don't understand what you want to tell me by "any number of forms".
15:02	dysfun	(when (foo) (bar) (baz)) ; calls bar, then baz, returns (baz)
15:03	justin_smith	RedNifre: (f) is a form
15:03	RedNifre	Yes, I think I understand. And I could do (if bla (do a b c)), right?
15:03	justin_smith	sure, and that's what when is
15:03	justin_smith	when just looks nicer
15:03	RedNifre	Okay, I guess I agree with you then that when is nicer than an else-less if. But I don't understand why an else-less if is even allowed.
15:03	dysfun	these "not strictly necessary" things actually make clojure quite nice
15:04	RedNifre	Hm, I guess you can just comment out the "else" part, huh?
15:04	RedNifre	...without rewriting it to a "when"...
15:04	justin_smith	RedNifre: no need for a comment...
15:04	justin_smith	,(if true 1)
15:04	clojurebot	1
15:05	justin_smith	,(if false 1)
15:05	clojurebot	nil
15:05	RedNifre	No, I meant if you had (if bla (println "fine") (println "not fine")) and you quickly wanted to change it to not print "not fine" then you could comment out that line without being forced to rewrite it to a "when".
15:05	justin_smith	I mean, I guess, sure
15:05	dysfun	not if you use a line-comment like most people, because the parens need to match
15:06	RedNifre	ah, right, I had java style parens in mind.
15:06	RedNifre	so when to use an else-less if?
15:06	dysfun	you could use #_ though
15:06	justin_smith	,(#_#_#_#_#_#_#_#_#_ we have better things than end of line comments)
15:06	clojurebot	()
15:06	dysfun	lol
15:06	dysfun	personally i won't be using the else-less if now i know about it
15:06	justin_smith	please don't use #_ like that, with the sole exception of commenting a matching binding/value pair in let or a hash map with #_#_
15:07	RedNifre	,(#_ 1 2)
15:07	clojurebot	#error {\n :cause "java.lang.Long cannot be cast to clojure.lang.IFn"\n :via\n [{:type java.lang.ClassCastException\n :message "java.lang.Long cannot be cast to clojure.lang.IFn"\n :at [sandbox$eval97 invokeStatic "NO_SOURCE_FILE" 0]}]\n :trace\n [[sandbox$eval97 invokeStatic "NO_SOURCE_FILE" 0]\n [sandbox$eval97 invoke "NO_SOURCE_FILE" -1]\n [clojure.lang.Compiler eval "Compiler.java" 6927]...
15:07	justin_smith	RedNifre: that expands to (2)
15:07	RedNifre	thanks.
15:07	justin_smith	,(#_#_ 1 2)
15:07	clojurebot	()
15:07	justin_smith	my chain of #_ was perhaps less random than it looked
15:08	dysfun	do you like showing off in front of newbs?
15:08	RedNifre	how does that work exactly?
15:08	justin_smith	RedNifre: #_ eats exactly one form
15:08	justin_smith	RedNifre: so N #_ eats N forms
15:08	kwladyka	"Boot is a build tool. That said it's task composition features only get to shine when multiple build steps are involved." <- is it not job for Continuous Integration or another tool? I mean shouldn't it be separated for lein + tool to deploy?
15:08	RedNifre	why can you type them without spaces between them?
15:08	justin_smith	kwladyka: boot is a replacement for lein
15:09	dysfun	RedNifre: because the reader is special
15:09	justin_smith	RedNifre: they are reader macros, they don't obey the rules regular symbols do
15:09	justin_smith	RedNifre: another way to put it is for the same reason you can interchange [ [ ] ] with [[]]
15:10	RedNifre	Can you change as many as you want or are they defined separately, i.e. #_ and #_#_ and #_#_#_ up to, say 20 or something?
15:10	justin_smith	both are using the readers lowest level rules about where forms begin and end
15:10	RedNifre	*chain, not change
15:10	dysfun	in theory, they're not limited. in practice, who knows?
15:10	dysfun	don't overuse them
15:10	justin_smith	RedNifre: there might be some stack overflow issue, I really shouldn't have even showed that silly #_#_#_#_#_ trick
15:11	dysfun	justin_smith: on a pushbackreader?
15:11	RedNifre	"same reason .. [[]]" I thought I can type [[]] because in clojure, square brackets work just like normal parens (unlike in other lisps where there are only regular parens)
15:11	justin_smith	RedNifre: same reason ( ( f ) ) is the same as ((f))
15:11	justin_smith	RedNifre: these are all reader rules
15:11	dysfun	or because there are special rules for interpreting parens and square barackets
15:12	RedNifre	hm, I'll ignore #_ for now...
15:12	justin_smith	RedNifre: what I mean is that #_ being special is on the same level as () or [] or {} being special, none of these need spaces for parsing
15:12	dysfun	when we say lisp has 'no syntax', we mean it has as little as we can get away with
15:12	justin_smith	exactly
15:13	RedNifre	Heh, I actually CAN comment the whole "else" line in an "if" because parinfer fixes the missing paren.
15:13	dysfun	nice
15:13	justin_smith	well there you go
15:13	justin_smith	but #_ can be more elegant sometimes
15:13	dysfun	and it works in all editors
15:14	RedNifre	alright
15:14	justin_smith	I am going to go to the office and try to catch up on my day job where I write clojure now. Yay!
15:14	dysfun	also use sparingly
15:15	RedNifre	Now the tutorial introduced the "=" operator but didn't say much about it. Is it as strange as in Java (don't compare Strings that way! Integer autoboxing doesn't happen but it works for the first 127 Integers anyway!) or is it more like calling the "equals" method?
15:15	justin_smith	RedNifre: we don't have operators
15:15	justin_smith	= is a function
15:16	justin_smith	and it's more like the equals method
15:16	RedNifre	okay
15:16	justin_smith	,(= () [])
15:16	RedNifre	so it's sane and I don't have to learn any special rules, huh?
15:16	clojurebot	true
15:16	justin_smith	RedNifre: is the above sane?
15:16	justin_smith	depending on your opinion of that, it may or may not be sane
15:16	justin_smith	,(= 1.0 1)
15:16	clojurebot	false
15:17	RedNifre	hey!
15:17	RedNifre	Well, (= () []) to me would be undefined behaviour since I'm comparing two things with different type so I don't worry about it... on the other hand...
15:17	RedNifre	hmmmm...
15:17	dysfun	we say clojure data have value semantics - we always compare their values, not their references
15:17	justin_smith	structural equility for immutable things is pretty nice I think
15:18	justin_smith	dysfun: but haskell has that too, but it still wouldn't call two different types equal
15:18	justin_smith	which is where structural equality comes into play
15:18	justin_smith	structural equality is kind of cool but also weird but also useful
15:19	RedNifre	well, Haskell would compile (= 1.0 1) as (= 1.0 1.0) since the first number is obviously float so the second one must be float as well, otherwise you wouldn't compare the same type. Go won't compile it because you try to compare different types (no overloaded number literals there). Java would compare the numbers I think?
15:19	justin_smith	I still find (= () []) and (not= 1 1.0) a quirky combo of behaviors :)
15:20	kwladyka	justin_smith replacement? More like another tool not replacement?
15:20	dysfun	i quite like 'shape typing'
15:20	RedNifre	What's the justification for (= 1 1.0) being false?
15:20	justin_smith	kwladyka: boot is meant to replace lein - you can use one or the other, there's rarely need to use both, ideally never need to use both
15:20	dysfun	well for a start, floats are approximations of numbers :)
15:20	RedNifre	but in this case it approximates 1 perfectly.
15:21	neoncont_	justin_smith: is (= ["structural equality" "isomorphism"])?
15:21	justin_smith	RedNifre: for another potentially confusing detail, we have == for numeric value equality that ignores type
15:21	kwladyka	justin_smith just not sure about idea of boot. Is not better to have lein + CI instead of boot?
15:21	kwladyka	i didn't use boot so i don't know details
15:21	dysfun	kwladyka: boot is like lein, but different
15:21	justin_smith	,(== 1 1.0 3/3)
15:21	clojurebot	true
15:21	dysfun	since i started porting my stuff to support clojurescript, i find boot a better fit
15:22	RedNifre	okay, but can I use == on other things?
15:22	justin_smith	kwladyka: boot starts faster, has a cleaner implementation, and is imperative instead of declarative. Some people like these things.
15:22	dysfun	it doesn't start faster here
15:22	justin_smith	RedNifre: no, only Number instances
15:22	justin_smith	dysfun: perhaps I was misled
15:22	kwladyka	dysfun can you give more details why?
15:22	RedNifre	If (= 1 1.0) is false and (== 1 1.0) is true I would expect (= () []) to be false and (== () []) to be true.
15:22	dysfun	they're both slow here
15:23	justin_smith	RedNifre: that would be consistent but sadly is not the case
15:23	dysfun	kwladyka: because i get to have one watcher to update everything
15:24	kwladyka	dysfun watcher?
15:24	dysfun	for instance i have a task that watches for updates and then runs the clojure tests and then the clojurescript ones
15:24	justin_smith	RedNifre: I think the idea is that turning '(a b c) into '[a b c] loses no information, no matter what a b and c are
15:24	justin_smith	RedNifre: you can't say the same about number types
15:24	dysfun	a watcher is simply a builtin boot facility that watches for file changes
15:24	RedNifre	Well, I'm new to Clojure so I might not have the right perspective here but right now those seem like the worst equality rules I have ever seen (aside from javascript's 1 == "1")
15:24	kwladyka	dysfun and that is the point. Isn't it job for CI software like teamcity ?
15:24	kwladyka	dysfun oh in that way
15:24	dysfun	RedNifre: they're not a bad set really, but always ask what you want
15:25	kwladyka	dysfun if i know lein can do the same with cljs
15:25	dysfun	kwladyka: no, boot is like leiningen
15:25	dysfun	you do want to run your tests before you push them don't you?
15:25	justin_smith	RedNifre: as was discussed above with mmastic, we don't really care about types most of the time, we care about protocols. Structural equality works for structures that implement the right protocols to be compared as equivalent.
15:25	justin_smith	RedNifre: also, = works between numeric subtypes that agree on the exact / lossy divide
15:25	justin_smith	,(= 1 3/3)
15:25	clojurebot	true
15:25	justin_smith	,(= 1 1N)
15:25	clojurebot	true
15:25	RedNifre	wat
15:26	justin_smith	,(= (float 1.0) (double 1.0))
15:26	clojurebot	true
15:26	kwladyka	dysfun yes but not after any change in files during editing
15:26	RedNifre	,3/3
15:26	clojurebot	1
15:26	RedNifre	,1/3
15:26	clojurebot	1/3
15:26	dysfun	well maybe you don't want that
15:26	justin_smith	RedNifre: it's a syntax for creating rationals, rationals autopromote to longs as applicable
15:26	dysfun	i find it really useful
15:26	RedNifre	wat
15:26	dysfun	i like real time feedback
15:26	RedNifre	why do rationals autopromote to longs but floats don't?
15:27	kwladyka	dysfun if it is very small app it could be ok
15:27	justin_smith	RedNifre: rationals are exact
15:27	justin_smith	RedNifre: floats are lossy
15:27	justin_smith	,(+ 1/3 2/3)
15:27	clojurebot	1N
15:27	dysfun	kwladyka: i don't understand why must it be small?
15:27	RedNifre	,1N
15:27	clojurebot	1N
15:27	kwladyka	dysfun what if tests take 30 second and run after any change in any files?
15:27	justin_smith	RedNifre: are you familiar with the pitfalls of ieee floating point? eg. why you should hardly ever compare them for equality?
15:27	RedNifre	Now hang on, if 1N doesn't turn into 1, why is (= 1 1N) true?
15:27	kwladyka	it will be iritating
15:27	dysfun	if your tests take 30 seconds, you're doing them wrong
15:28	luma	,(+ 0.1 0.2)
15:28	clojurebot	0.30000000000000004
15:28	RedNifre	yes, I'm aware of that.
15:28	dysfun	most of mine run basically instantaneously
15:28	justin_smith	RedNifre: because they are on the same side of the exact/inexact divide
15:28	kwladyka	dysfun i can't agree with that :)
15:28	justin_smith	RedNifre: there is no lossless translation across that divide
15:28	kwladyka	dysfun because it is simple app
15:28	dysfun	mostly i develop libraries actually
15:28	justin_smith	RedNifre: but we treat two numbers on the same side as equal
15:28	RedNifre	well, there is sometimes. So I guess clojure is being consistent by pretending that you can never translate lossless?
15:29	dysfun	obviously if you have to have a database etc. it will take longer
15:29	kwladyka	dysfun if you count more complex algorithm or do more complex things it takes a time
15:29	RedNifre	I mean, I can understand that (= 1 (* 10 (/ 1.0 10.0))) would be false because of floating point inaccuracies.
15:29	dysfun	if you're doing machine learning, obviously you're not going to have it update in real time
15:29	justin_smith	,(= 1/2 0.5M) ; maybe this is wrong though, this totally could be treated as equal
15:29	clojurebot	false
15:30	RedNifre	what's M again?
15:30	RedNifre	...and what's N?
15:30	kwladyka	i am going watch the movie. Thank you for discussion. I will be back after 2 hours :)
15:30	justin_smith	,(type 0.5M)
15:30	clojurebot	java.math.BigDecimal
15:30	justin_smith	,(type 1N)
15:30	clojurebot	clojure.lang.BigInt
15:30	RedNifre	aha.
15:30	justin_smith	both are lossless numbers
15:30	RedNifre	okay, so since floats are binary and BigDecimals are decimals I can see that they can't be compared for equality because that might be lossless.
15:31	dysfun	the takeaway from all of this is : think before you write a comparison
15:31	RedNifre	wait, BigDecimal can't be lossless.
15:31	justin_smith	RedNifre: not just decimals, auto-promoting so that they don't lose data (up to some limit)
15:31	justin_smith	right, there is actually a limit
15:31	dysfun	they definitely at that range
15:32	justin_smith	RedNifre: instead of losing precision, bigdecimal will just fall over
15:32	justin_smith	,(/ 1.0M 2.0M)
15:32	clojurebot	0.5M
15:32	RedNifre	Okay, so the way I understand it is this: If a comparison could lead to a wrong result because of lossy representation the comparison will always be false even if it would actually be a precise comparison in the concrete case.
15:32	justin_smith	,(/ 1.0M 5.0M)
15:32	clojurebot	0.2M
15:32	justin_smith	hmm...
15:32	RedNifre	,(/ 1.0M 3.0M)
15:32	justin_smith	,(/ 1.0M 3.0M)
15:32	clojurebot	#error {\n :cause "Non-terminating decimal expansion; no exact representable decimal result."\n :via\n [{:type java.lang.ArithmeticException\n :message "Non-terminating decimal expansion; no exact representable decimal result."\n :at [java.math.BigDecimal divide "BigDecimal.java" 1616]}]\n :trace\n [[java.math.BigDecimal divide "BigDecimal.java" 1616]\n [clojure.lang.Numbers$BigDecimalOps div...
15:32	clojurebot	#error {\n :cause "Non-terminating decimal expansion; no exact representable decimal result."\n :via\n [{:type java.lang.ArithmeticException\n :message "Non-terminating decimal expansion; no exact representable decimal result."\n :at [java.math.BigDecimal divide "BigDecimal.java" 1616]}]\n :trace\n [[java.math.BigDecimal divide "BigDecimal.java" 1616]\n [clojure.lang.Numbers$BigDecimalOps div...
15:32	justin_smith	right
15:33	justin_smith	RedNifre: that sounds about right, yeah
15:33	RedNifre	That's funny, so BigDecimals avoids being lossy by crashing when it would get lossy?
15:34	RedNifre	,(* 10.0 (/ 1.0 10.0))
15:34	clojurebot	1.0
15:34	dysfun	if you're hitting the limit, you weren't checking your inputs sufficiently
15:34	RedNifre	,(/ 1.0 10.0)
15:34	clojurebot	0.1
15:35	RedNifre	Is "1.0" a float or a BigDecimal?
15:35	justin_smith	,(* 3 1/3)
15:35	clojurebot	1N
15:35	justin_smith	1.0 is double
15:35	dysfun	well it's a string, but without the quotes it would be a double
15:35	justin_smith	I guess float prints that way too, but clojure strongly prefers doubles
15:35	dysfun	there's little reason to prefer floats
15:36	RedNifre	wasn't 0.1 rounded to a double something like 0.1000000000000000000004 ?
15:36	justin_smith	yeah, I think that's some kind of printing rule
15:36	dysfun	there isn't much reason to scrimp on integers these days tbh
15:36	RedNifre	,(= 10.0 (* 10.0 (/ 1.0 10.0)))
15:36	clojurebot	false
15:36	dysfun	(unless you're abusing pointer packing, in which case i salute you)
15:36	RedNifre	,(= 1.0 (* 10.0 (/ 1.0 10.0)))
15:36	clojurebot	true
15:37	RedNifre	Maybe I'm thinking about some other binary floating point issue, but I thought 1 / 10 * 10 wasn't 1 in IEEE?
15:37	dysfun	you shouldn't be testing floats for equality anyway
15:38	justin_smith	,(format "%20.420f" 0.1)
15:38	clojurebot	"0.1000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000...
15:38	justin_smith	sorry
15:39	RedNifre	dysfun I know, but I thought the reason was that (= 1.0 (* 10.0 (/ 1.0 10.0))) would be false because of float inaccuracies, so I'm surprised that it works.
15:40	RedNifre	I also think that clojurebot's output has more precision than a double.
15:40	dysfun	oh, it's one of those things where it often does, but you shouldn't rely on it
15:40	dysfun	that makes for very difficult to diagnose bugs
15:40	justin_smith	RedNifre: I asked for a specific number of zeros
15:40	dysfun	anyway, hometime
15:41	RedNifre	justin_smith can you elaborate?
15:42	RedNifre	what exactly did clojurebot output there? Was it a double?
15:42	justin_smith	RedNifre: I ran ,(format "%20.420f" 0.1) which asks for a specific number of digits, padded with zeros even after precision runs out
15:42	justin_smith	RedNifre: it outputted a string, as format returns string
15:42	justin_smith	"outputted" I R SMRT
15:45	RedNifre	Well, my internet connection is too slow to google the precision of JVM doubles but if it's 64 bit then I don't understand how clojurebot can output something so close to 0.1 from a double.
15:47	RedNifre	Another thing, does "==" compare exactly, or does it compare within the precision of IEEE?
15:47	justin_smith	(Double/mulp 0.1)
15:47	justin_smith	,(Double/mulp 0.1)
15:47	clojurebot	#error {\n :cause "No matching method: mulp"\n :via\n [{:type clojure.lang.Compiler$CompilerException\n :message "java.lang.IllegalArgumentException: No matching method: mulp, compiling:(NO_SOURCE_PATH:0:0)"\n :at [clojure.lang.Compiler analyzeSeq "Compiler.java" 6875]}\n {:type java.lang.IllegalArgumentException\n :message "No matching method: mulp"\n :at [clojure.lang.Compiler$StaticMet...
15:47	justin_smith	err...
15:47	RedNifre	,(Double/ulp 0.1)
15:47	clojurebot	#error {\n :cause "No matching method: ulp"\n :via\n [{:type clojure.lang.Compiler$CompilerException\n :message "java.lang.IllegalArgumentException: No matching method: ulp, compiling:(NO_SOURCE_PATH:0:0)"\n :at [clojure.lang.Compiler analyzeSeq "Compiler.java" 6875]}\n {:type java.lang.IllegalArgumentException\n :message "No matching method: ulp"\n :at [clojure.lang.Compiler$StaticMethod...
15:47	RedNifre	worth a shot...
15:48	justin_smith	,(Math/ulp 0.1)
15:48	clojurebot	1.3877787807814457E-17
15:48	RedNifre	right, so it's 17 decimal digits. But clojureput output way more than 17 zeroes, so how does that work?
15:48	justin_smith	,(-> 0.1 (- 1.3877787807814457E-17) (+ 1.3877787807814457E-17))
15:48	clojurebot	0.1
15:48	justin_smith	RedNifre: like I said I used format, format says "give me this many zeros on a string"
15:49	justin_smith	clojurebot gave me a string, not a double
15:49	RedNifre	ah, you mean it first "rounds" it to the string "0.1" and then just adds zeros for fun?
15:49	justin_smith	RedNifre: I was hoping using a long format would expose precision, but we got 0.1 back anyway
15:50	justin_smith	so yeah, pretty much
15:50	justin_smith	not for fun, because my format string said add that many zeros
15:50	RedNifre	okay, so how CAN you expose precision?
15:51	justin_smith	looking at the ulp? getting the raw bits and the implementation rules and doing the math?
15:51	justin_smith	not sure
15:51	justin_smith	actually going this time, be back soon when I get to the office
15:53	rotcev	hi, say i have a list in the form of ((+ 1) (+ 2) (- 3)), what is the best way to get it into the form (+ 1 (+ 2 (- 3))), ive been trying for a while but cant seem to come up with a nice way
15:54	RedNifre	hm, maybe reverse it and reduce it with something like apply or invoke or -> or ->>?
15:56	rotcev	RedNifre: at the moment im doing http://hastebin.com/uverajaziw.lisp with input of (infix (1 + 2 + 3 - 5)) which results in ((+ 1) (+ 2) (- 3) (5))
15:56	RedNifre	hang on, I'm new to this so I need a moment to think :)
15:56	rotcev	which isnt even ideal tbh cos ideally the 5 would be paired in with the 3 but im kinda new to clojure so i dont know how to work partition to the way i need it (unless i should go about it a diff way)
15:56	RedNifre	your link gives me an application error.
15:56	RedNifre	but I'm also on a bad connection.
15:57	rotcev	it just worked for me site just went down lol ill pastebin it
15:57	rotcev	RedNifre: http://pastebin.com/sibdb4Ci
15:58	RedNifre	Hm, looks like (reduce -> ... doesn't work because "->" is a macro...
15:59	amalloy	i don't think you can really transform your list in that way efficiently. it's not too hard to do inefficiently
16:00	rotcev	my ideal output would be (+ 1 (+ 2 (- 3 5))) so i could just use eval on it
16:01	rotcev	er not even, itd be ( + 1 ( + 2 ( - 3 5))) or something no need to eliminate spaces
16:02	rotcev	i was thinking itd be cool if i could somehow treat each list as a partial function
16:02	rotcev	is there some way to do that in clojure? (in this specific case)
16:03	RedNifre	Is there something like hoogle for clojure?
16:04	rotcev	clojuredocs
16:06	mgaare	rotcev: do you need to consider order of operations? in other words, will you ever see multiplication, division, more parens, etc?
16:06	amalloy	RedNifre: nothing nearly as good
16:06	RedNifre	well, how do I append a form to a list?
16:07	RedNifre	I can only think about insane ways involving cons and reverse.
16:07	rotcev	mgaare: probably but i was thinking it would just be the order of the expressions in reverse for operator precedence
16:08	rotcev	and since i was just gonna use eval to read it i kinda assumed it would end up magicly working in the end lol
16:09	RedNifre	ah, I'm making progress here... let me think this through...
16:12	rotcev	i think im making progress too ;o
16:12	amalloy	why are you trying to munge this list around into a form that's suitable to eval? using eval is rarely a good answer, and getting it into shape for eval is harder than just evaluating it yourself with reduce
16:14	rotcev	true i just wasnt thinking correctly lol
16:14	amalloy	,(let [ops {'+ + '- -}] (reduce (fn [acc [op x]] ((ops op) acc x)) 0 '((+ 1) (+ 2) (- 3))))
16:14	clojurebot	0
16:16	RedNifre	,'(1 2)
16:16	clojurebot	(1 2)
16:16	RedNifre	,'('(1 2))
16:16	clojurebot	((quote (1 2)))
16:16	RedNifre	What's up whith that "quote"?
16:16	RedNifre	Why isn't it ((1 2)) ?
16:17	RedNifre	...ooooh
16:17	RedNifre	,'((1 2))
16:17	clojurebot	((1 2))
16:17	amalloy	that's how quoting works. it's not just the "make a list" operator
16:17	RedNifre	Ah, that solves everything.
16:17	amalloy	'('(1 2)) is shorthand for (quote (quote (1 2)))
16:18	RedNifre	rotcev I think I got it!
16:18	rotcev	:o
16:18	RedNifre	...though my solution is probably a bit crazy.
16:18	RedNifre	,(defn append [x,l] (reverse (cons x (reverse l))))
16:18	clojurebot	#'sandbox/append
16:19	RedNifre	(reduce append (reverse '((+ 1) (+ 2) (- 3))))
16:19	rotcev	the reverses rofl
16:19	RedNifre	,(reduce append (reverse '((+ 1) (+ 2) (- 3))))
16:19	clojurebot	(+ 1 (+ 2 (- 3)))
16:19	RedNifre	tadaa!
16:20	rotcev	nice
16:20	RedNifre	yeah, I guess there is already something like that append function in clojure, but I coludn't find it.
16:20	RedNifre	,(append (+ 1) (- 2))
16:20	clojurebot	#error {\n :cause "Don't know how to create ISeq from: java.lang.Long"\n :via\n [{:type java.lang.IllegalArgumentException\n :message "Don't know how to create ISeq from: java.lang.Long"\n :at [clojure.lang.RT seqFrom "RT.java" 542]}]\n :trace\n [[clojure.lang.RT seqFrom "RT.java" 542]\n [clojure.lang.RT seq "RT.java" 523]\n [clojure.core$seq__4357 invokeStatic "core.clj" 137]\n [clojure.co...
16:20	RedNifre	,(append '(+ 1) '(- 2))
16:20	clojurebot	(- 2 (+ 1))
16:21	mgaare	RedNifre: could also use concat, like
16:21	RedNifre	I tried concat, but that unpacket the second list too.
16:22	mgaare	,(defn append-cat [x xs] (concat xs (list x)))
16:22	clojurebot	#'sandbox/append-cat
16:22	amalloy	RedNifre: http://stackoverflow.com/q/5734435/625403
16:22	mgaare	,(append-cat '(+ 1) '((+ 2) (- 3)))
16:22	clojurebot	((+ 2) (- 3) (+ 1))
16:23	RedNifre	mgaare oh, so you wrap the list in a list to counteract concat's flattening?
16:23	mgaare	no, you wrap the single thing you're trying to append in a list
16:24	mgaare	although amalloy was kind enough to point out some shortcomings in that approach in that link ;)
16:33	rotcev	thanks for the guidance anyways guys i think i know another way to solve it which im trying to implement now
16:43	RedNifre	connection broke down
16:48	justin_smith	RedNifre: the standard way to append to a list is (concat l [e]), but if you know you will be doing only appends, it's easier to just make a vector and conj
16:48	justin_smith	oops, scrollback
16:48	justin_smith	maybe still relevant though...
16:48	justin_smith	,(defn append' [l & args] (concat l args))
16:48	clojurebot	#'sandbox/append'
16:48	RedNifre	yeah, you missed my first clojure solution for somebody else's problem.
16:49	justin_smith	,(append' '(:a :b :c) :d :e :f)
16:49	clojurebot	(:a :b :c :d :e ...)
16:49	RedNifre	,(append' '(+ 2) '(- 3))
16:49	clojurebot	(+ 2 (- 3))
16:50	RedNifre	ah, it's backwards compared to mine.
16:50	RedNifre	I still have the Haskell convention in my head: First the special things, then the large data structures to operate on.
16:51	RedNifre	How would you solve the original problem with your append?
16:51	justin_smith	RedNifre: (reduce append' ...)
16:51	justin_smith	RedNifre: instead of reversing etc.
16:52	RedNifre	I'm now at the macro part of the tutorial. Could everything that can be done with macros also be done with regular functions and quoted source code?
16:52	justin_smith	RedNifre: if you are allowed to use eval, yes
16:52	RedNifre	,(reduce append' '((+ 1) (+ 2) (- 3)))
16:52	clojurebot	(+ 1 (+ 2) (- 3))
16:52	justin_smith	otherwise other macros will trip you up sometimes
16:53	justin_smith	RedNifre: that's not right is it
16:53	RedNifre	not quite, huh?
16:53	RedNifre	Is there a reduce-left?
16:53	justin_smith	,(defn put-in [[a b] el] [a el b])
16:53	clojurebot	#'sandbox/put-in
16:53	RedNifre	ah, so macros are better in that case because they expand at compile time so you don't need eval?
16:54	justin_smith	,(reduce put-in '((+ 1) (+ 2) (- 3)))
16:54	clojurebot	[+ (- 3) (+ 2)]
16:54	justin_smith	still not it
16:54	justin_smith	yeah I guess the reversing is needed regardless
16:55	RedNifre	I think you have to reduce/fold from the right, otherwise you have to drill into your nested lists with different depth each step.
16:55	justin_smith	right
16:56	justin_smith	,(reduce put-in (reverse '((+ 1) (+ 2) (- 3))))
16:56	clojurebot	[- (+ 1) (+ 2)]
16:56	justin_smith	haha, well
16:57	justin_smith	right, so your answer was the one then
16:57	RedNifre	wait, where did the 3 go?
16:57	RedNifre	,'[(1 2)]
16:57	clojurebot	[(1 2)]
16:57	justin_smith	RedNifre: disappeared in a destructure that made a bad assumption
16:57	justin_smith	,(let [[a b] [1 2 3]] [a b])
16:57	clojurebot	[1 2]
17:00	RedNifre	I'm now reading about ' quoting and ` syntax quoting. So I can interpolate with ~ in ` but not in '. Why does ~ not work in '?
17:00	justin_smith	because it's a special syntax that only exists inside `
17:00	justin_smith	just like you can only catch inside try
17:02	justin_smith	,'```(do :a)
17:02	clojurebot	(clojure.core/seq (clojure.core/concat (clojure.core/list (quote clojure.core/seq)) (clojure.core/list (clojure.core/seq (clojure.core/concat (clojure.core/list (quote clojure.core/concat)) (clojure.core/list (clojure.core/seq (clojure.core/concat (clojure.core/list (quote clojure.core/list)) (clojure.core/list (clojure.core/seq #))))) (clojure.core/list (clojure.core/seq (clojure.core/concat (clo...
17:03	RedNifre	,(inc 1)
17:03	clojurebot	2
17:04	RedNifre	Well, would there be a downside to '(1 ~(inc 1)) producing (1 2) ?
17:04	justin_smith	RedNifre: it would mean ' only exists in order to create crappy name capture that causes bugs
17:05	lodin-	RedNifre: I guess the question is why not use `(1 ~(inc 1)).
17:05	justin_smith	as it is, name capture isn't an issue (at least less trivially an issue) because ' does not interpolate
17:05	RedNifre	But then my question would be why not always use ` instead of '?
17:06	justin_smith	RedNifre: ` does interpolation and also namespace qualifying
17:06	justin_smith	it's much more complicated
17:06	lodin-	RedNifre: Because `x resolves x, while 'x is a literal symbol.
17:06	justin_smith	,'`(do :a) ; compare this to the next
17:06	clojurebot	(clojure.core/seq (clojure.core/concat (clojure.core/list (quote do)) (clojure.core/list :a)))
17:06	justin_smith	,''(do :a)
17:06	clojurebot	(quote (do :a))
17:07	lodin-	RedNifre: Maybe resolves is not right. justin_smith said it better.
17:07	RedNifre	,'x
17:07	clojurebot	x
17:07	RedNifre	,`x
17:07	clojurebot	sandbox/x
17:07	lodin-	,'(let [x 1])
17:07	clojurebot	(let [x 1])
17:07	lodin-	,`(let [x 1])
17:07	clojurebot	(clojure.core/let [sandbox/x 1])
17:07	lodin-	The second will give you an error.
17:08	RedNifre	ah, so quoting is more like source code whose meaning depends on where it gets executed while syntax quoting actually works out precisely what each form means?
17:09	justin_smith	RedNifre: somewhat - there's a history of buggy macros that "capture" surrounding values
17:09	justin_smith	going way back into LISP times
17:09	justin_smith	syntax quoting, which resolves things at macro definition, is a way of preventing these bugs
17:10	RedNifre	It's all a bit muddy to me, I still don't understand why I wouldn't just use syntax quoting always. Why would the second one of lodin-'s example give me an error?
17:10	justin_smith	RedNifre: you can't use a fully qualified symbol as a local binding
17:11	justin_smith	the reason ` turns it into a fully qualified symbol is to keep it from shadowing local bindings
17:11	lodin-	RedNifre: The thing is, you would not want to get (clojure.core/let [x 1]) either, because then you (might) shadow an x.
17:12	justin_smith	imagine you have (defn foo [a] (frob (+ a a))) and then (defmacro frob [form] `(let [a "dog"] (~form))) and a inside the macro was not modified
17:12	justin_smith	the macro would end up compiling to (+ "dog" "dog")
17:12	justin_smith	because it captures a symbol
17:13	justin_smith	the original a is inaccessible in the macro, since the name is shadowed
17:13	justin_smith	I think there's more than one mistake in that example, but I hope you get the gist of it
17:14	RedNifre	I'm not sure, the macro looks like you want to shadow a? Or what is (let [a "dog"]... meant to achieve?
17:15	justin_smith	RedNifre: the example is bad and it should feel bad, imagine a was somehow useful in that macro.
17:16	RedNifre	Well, I see how a gets shadowed but I don't understand the implications.
17:16	justin_smith	RedNifre: it means implementation details of a macro you call (the names it gives internal bindings) change the meaning of code that calls it.
17:16	lodin-	RedNifre: The macro author does not know what the user will or won't have in the form. So no names would be safe.
17:17	justin_smith	where some magic binding name leads to totally different behaviors
17:17	RedNifre	can you give an example of how you would write your example to prevent that problem?
17:17	lodin-	RedNifre: This is why we have a#.
17:17	lodin-	,`(let [x# 1])
17:17	clojurebot	(clojure.core/let [x__25__auto__ 1])
17:17	justin_smith	RedNifre: (defmacro frob [form] `(let [a# "dog"] (~form))) - a# expands to a gensym, a guaranteed globally unique symbol
17:17	RedNifre	hmmm... so in my syntax quoted macros I should add a # to variable names to prevent shadowing?
17:17	lodin-	RedNifre: So never use names like __<somenumber>__auto__ :-)
17:18	justin_smith	RedNifre: you need to add a # or it will refuse to even compile
17:18	justin_smith	lodin-: gensym is smart enough to still make a name that doesn't conflict if you do that though
17:18	justin_smith	afaik
17:18	lodin-	Would be the most confusing macroexpanded code ever though. :-)
17:18	RedNifre	But what if I want to do (frob (str "Hey " a ", go fetch!")) ?
17:19	justin_smith	RedNifre: it would tell you a is unbound
17:19	justin_smith	RedNifre: clojure doesn't like spooky action at a distance, we do lots of things that discourage it
17:19	justin_smith	or make it difficult to implement
17:19	lodin-	RedNifre: So if you do want to use a "local" name, then you can do that, by interpolating a literal symbol. And there are legitimate reasons for doing that.
17:19	RedNifre	I'm surprised, I thought macros just rewrote the syntax tree.
17:20	justin_smith	RedNifre: "just" - we are very opinionated about how that "should" happen - but yeah, if you use regular ' you can make anything work
17:20	justin_smith	and the bugs this inevitably causes are now your burden
17:20	RedNifre	But it sounds like a sensible restrictions, I mean, getting extra stuff from a macro would be strange.
17:20	lodin-	,`(let [~'x 1])
17:20	clojurebot	(clojure.core/let [x 1])
17:21	justin_smith	RedNifre: lodin-: great example of legit use of intentional shadowing is the #() reader macro
17:21	justin_smith	,'#(+ % %)
17:21	clojurebot	(fn* [p1__74#] (+ p1__74# p1__74#))
17:21	justin_smith	in that example, % was magic, and refers to a binding the compiler creates
17:22	justin_smith	we accept it as given that % will be the first arg in the generated function, and substituted smartly in the function body
17:22	RedNifre	Okay, so... a macro may rearrange what you put into it but it won't/shouldn't add anything surprising?
17:22	justin_smith	well, that's getting into philosophy I guess...
17:22	justin_smith	haha
17:23	justin_smith	but yes, best to avoid surprises, just as with any other code I'd think
17:23	RedNifre	What I mean is you can't do (library-in-a-macro (foo "look, the macro gave me a foo function I can use!"))
17:23	justin_smith	right, that's probably a bad idea
17:24	RedNifre	I'm not sure if I understood if that's even possible or not.
17:24	RedNifre	I think you said not using # at the end of "foo" would be a compile error, but there is intentional shadowing in some reader?
17:26	RedNifre	The macro can't do "(let [foo println]" because that won't compile, right? So how would the macro provide a foo function to the... what's it called, macro content?
17:26	lodin-	RedNifre: By interpolating a (unqualified) symbol.
17:27	lodin-	,(defmacro foo [form] `(let [~'x 42] ~form))
17:27	clojurebot	#'sandbox/foo
17:28	lodin-	,(foo x)
17:28	clojurebot	42
17:29	RedNifre	I guess it'll take some time until I aquire an intuition for what I should and shouldn't do with macros...
17:30	justin_smith	RedNifre: two groups of people should write macros - novices who need to figure out what the hell the deal is with macros, and masters of the language who need to offer new syntax back to the community. In between they are almost always a mistake.
17:30	lodin-	RedNifre: If you write a program that, you know, actually do useful stuff, you don't need to write any macro. the clojure.core macros plus functional abstraction will take you pretty far.
17:30	justin_smith	yeah, exactly
17:31	justin_smith	but the awesome thing is, when someone sees that we need eg. core.async or core.logic, the tools are there to do it within the regular language, without forking it
17:32	justin_smith	because those things would be pretty useless without the new syntaxes which make their features usable
17:36	RedNifre	So do you people use clojure at the office?
17:37	justin_smith	RedNifre: right now I should be writing clojure code but am procrastinating
17:37	justin_smith	literally sitting at my desk in the office
17:37	RedNifre	Well, how did clojure take hold in your office? Or did your company always use some lisp or other fp language?
17:37	justin_smith	they decided to convert the ruby app to clojure, so then they hired me to make it happen
17:38	RedNifre	Ah, ruby to clojure makes sense I guess.
17:38	RedNifre	(I was asking because I'm having a hard time imagining my java office even consider something like clojure)
17:38	justin_smith	RedNifre: it was a bundle of ruby services making up an app, someone converted one to clojure because it needed to be concurrent, they saw how much faster development was on that service, the lower defect rate, and the better performance, and eventually opted to redo the rest of it too
17:38	DynamicMetaFlow	What factors would lead someone to go from a Ruby app to Clojure?
17:39	justin_smith	RedNifre: the two big things would be dev time and defect rate, even in a java environment
17:39	justin_smith	DynamicMetaFlow: wanting to spend less money on servers, faster dev on mature apps with lower defect rate (immutability helps a lot here)
17:40	justin_smith	DynamicMetaFlow: on the other hand, the initial ramp-up for a proof of concept is much faster with ruby - that hits a limit for most devs though
17:40	DynamicMetaFlow	What do you mean by "ramp-up for a proof of concept
17:41	DynamicMetaFlow	Do you mean prototyping or something else
17:41	justin_smith	DynamicMetaFlow: going from "we should make an app that does X" to having a first prototype
17:41	justin_smith	exactly, prototyping
17:41	justin_smith	so ruby probably prototypes faster, but clojure is more likely to end up with something maintainable (if done idiomatically), and can be almost as fast to prototype
17:41	DynamicMetaFlow	That's interesting, I've heard claims of the same fast prototyping in Clojure
17:42	justin_smith	DynamicMetaFlow: sure, but I think with things like rails, you can really get a first proof of concept of something that looks slick and has all the moving parts very fast
17:42	justin_smith	clojure can compete, but I don't think it's quite as instant
17:43	DynamicMetaFlow	Yeah, I've picked up Python but haven't practiced in a while. I did learn a little Ruby and then made a complete switch to Common Lisp and now I want to entertain Clojure because of the JVM. At this point though I just need to sit with one language
17:43	justin_smith	DynamicMetaFlow: yeah, that makes sense. All the stuff the jvm makes available is pretty useful if you need modern libraries - because the jvm has libs for just about everything.
17:43	DynamicMetaFlow	That's a good point. I remember someone in a podcast saying that Rails is what popularized Ruby and to an effect clojurescript will hopefully do the same for Clojure. It was an interesting podcast
17:44	justin_smith	DynamicMetaFlow: yeah, I think cljs, plus reagent and figwheel and ring could do that
17:45	DynamicMetaFlow	Right now I'm thinking of learning more Ruby to at least help out in different projects to contribute to but long term make the switch to Clojure
17:46	justin_smith	cool, hope you stick with the plan to learn clojure, and find it as rewarding as many of us here have
17:47	rotcev	what's some good stuff to read on macros, i want to learn about unquoting or w/e idk what thats all about
17:47	RedNifre	Currently, Ruby is my go-to language for very small things (scripts with a couple hundred lines) because Ruby's focus is on programmer happiness and everything's allowed.
17:47	DynamicMetaFlow	I feel that when I was learning Common Lisp it's mental models is what worked in my head
17:47	RedNifre	I wouldn't use it for anything large though.
17:48	justin_smith	rotcev: the classic is "On Lisp" by that guy who founded y combinator
17:48	justin_smith	turns out he knows a shitload about macros
17:48	DynamicMetaFlow	Has anyone gone through this course from Eric Normand, http://www.purelyfunctional.tv/
17:48	justin_smith	the book is about common lisp, but it's all pretty easy to adjust to if you know clojure
17:48	rotcev	is a macro a lisp thing or a clojure specific feature
17:49	RedNifre	Hm, the "clojure for the brave and true" seems to be very theoretical. If I want to get my hands dirty and write a tiny command line program that uses a sqlite database, where would I start?
17:49	justin_smith	DynamicMetaFlow: I've heard great things about it, but have not. I do remember Eric Normand from when he hung out in this channel, and he knows his shit.
17:49	justin_smith	RedNifre: google for "clojure sqlite binding", check out the readme?
17:49	RedNifre	E.g. for node.js, the process was: 1. Find library on npm 2. ask on freenode where they tell you that the popular npm library is garbage 3. use what freenode recommends.
17:49	DynamicMetaFlow	Yeah, I listened to him on a podcast and I liked his thoughts regarding How to teach someone in programming
17:50	justin_smith	RedNifre: oh, a good ingredient here is going to the project for that lib on clojars and see how many downloads it has, and also going on crossclj.info to see what reputable libs and apps use it
17:50	RedNifre	is there something like hackage or npm for clojure?
17:50	DynamicMetaFlow	This was the podcast I listened to, I highly recommend it. https://devchat.tv/ruby-rogues/232-rr-teaching-and-how-we-can-all-do-more-to-teach-technical-topics-to-others-with-eric-normand
17:50	RedNifre	ah, thanks. I'll check it out.
17:51	RedNifre	You people don't happen to know about any beginner friendly command line and sqlite libraries, huh?
17:52	scottj	rotcev: neither, other languages have macros too. macros in clojure are very similar to those in most other lisps though.
17:53	scottj	RedNifre: familiar with https://github.com/razum2um/awesome-clojure and clojure awesome ?
17:54	RedNifre	No, I started some hours ago so I'm not familiar with anything.
17:54	justin_smith	rotcev: clojure macros are highly similar to common lisp macros, which is why paul graham's "on lisp" will likely teach you more than any other source I know of, but there is also some influence from scheme and the concept of hygeinic macros (though we don't use their model / syntax for that at all)
17:54	scottj	http://www.clojure-toolbox.com/
17:54	rotcev	could someone briefly explain the answer to 'why macros'
17:54	RedNifre	Ah, those links look excellent, thanks!
17:55	RedNifre	rotcev I think it's so you don't have to transform and then eval quoted source code.
17:55	justin_smith	or, alternately, fork the compiler
17:56	rotcev	does unquote just force an eval on a quote
17:56	rotcev	?
17:56	justin_smith	rotcev: macros allow the definition of new syntaxes. Which as you probably would guess isn't to often needed - but we constantly use those new syntaxes already developed, some which come with the language, some provided by libraries, all made with macros
17:56	rotcev	yeah i understand they are powerful thats why i want to be able to make my own
17:57	rotcev	xD
17:57	justin_smith	rotcev: a macro is a function that takes source code as an argument, and returns source code. the quote / unquote is a way of templating source code substitutions
17:58	justin_smith	but it works on the level of forms, not strings as eg. C macros do
17:58	RedNifre	are there meta macros that generate macros?
17:58	justin_smith	sure
17:58	justin_smith	RedNifre: sometimes the only reason you need to write a macro is that the functionality you need is only provided by a macro, so you need another macro to extend it
17:58	justin_smith	RedNifre: for example if you want a new special kind of defn that extends the existing defn macro
17:59	justin_smith	you could either recreate defn by scratch, or write a macro that expands to usage of defn
17:59	justin_smith	you can't just use a function and be compatible with defn, of course
17:59	justin_smith	since defn is a special syntax
17:59	RedNifre	Hm, can a macro expand to two copies of itself, crashing the compiler?
17:59	justin_smith	RedNifre: I bet it's possible
18:00	lodin-	RedNifre: Macros can be recursive, yes, if that's what you mean.
18:00	justin_smith	,(defmacro boom [x] `((boom ~x) (boom ~x)))
18:00	clojurebot	#'sandbox/boom
18:01	justin_smith	,(boom 42)
18:01	clojurebot	#error {\n :cause nil\n :via\n [{:type clojure.lang.Compiler$CompilerException\n :message "java.lang.StackOverflowError, compiling:(NO_SOURCE_PATH:0:0)"\n :at [clojure.lang.Compiler analyzeSeq "Compiler.java" 6875]}\n {:type java.lang.StackOverflowError\n :message nil\n :at [java.util.regex.Pattern$5 isSatisfiedBy "Pattern.java" 5151]}]\n :trace\n [[java.util.regex.Pattern$5 isSatisfiedBy...
18:01	justin_smith	RedNifre: there you go
18:01	justin_smith	macro-fork-bomb
18:02	RedNifre	hm, I wonder how hard it would be to find the bug. I'm not good at reading that error message but I guess in a real project it wouldn't tell you where the macro-fork-bomb happened, huh?
18:02	RedNifre	Meh, I guess there's always git bisect.
18:02	justin_smith	RedNifre: it would give you a line number instead of NO_SOURCE_PATH:0:0
18:02	justin_smith	and a file name
18:03	RedNifre	What's the limit of macros? I guess you couldn't compile ruby code using a macro since ruby has too many characters that have special meaning in clojure, e.g. ~ ?
18:03	rotcev	so is x in that example quoted source code, and the ~x unquotes it to be evaluated ?
18:04	justin_smith	yeah, you are limited to what works with the existing clojure reader rules, that all apply before macro expansion
18:04	justin_smith	rotcev: yes
18:04	RedNifre	okay, so no funky characters and the parens must match?
18:04	justin_smith	kind of
18:04	lodin-	RedNifre: The macro doesn't see any parens.
18:04	lodin-	RedNifre: The macro only sees Clojure data structures.
18:05	RedNifre	What I mean is that I could'n write a macro that works like (strange-macro )))))))
18:05	lodin-	RedNifre: This is a key point of this kind of macro.
18:05	TEttinger	like (+ 1 #_ "whee" 1) returns 2
18:06	TEttinger	it only sees what it's been given, (+ 1 1), since the #_ reader macro ignores "whee"
18:07	rotcev	#_ means ignore next value ?
18:07	TEttinger	I'm not sure if there's anything like #_ possible in user-written macros
18:07	TEttinger	yeah, discard
18:07	RedNifre	Okay, so could I write a macro for BF code, i.e. (bf +++>>>+[.+]) or something like that?
18:07	justin_smith	,(+ 1 #_ anything-goes-here! 1)
18:07	clojurebot	2
18:07	rotcev	nice
18:07	TEttinger	https://yobriefca.se/blog/2014/05/19/the-weird-and-wonderful-characters-of-clojure/
18:07	RedNifre	,(+ 1 #_ ))))) 1 )
18:07	clojurebot	#<RuntimeException java.lang.RuntimeException: Unmatched delimiter: )>
18:07	justin_smith	RedNifre: well, the delimiters would have to work
18:08	TEttinger	yeah, #_ discards one form
18:08	justin_smith	RedNifre: I think bf has situations where combos of delimiter chars are allowed that would be illegal in clojure
18:08	TEttinger	,(+ 1 #_{:a [1 2 3]} 1)
18:08	clojurebot	2
18:08	lodin-	RedNifre: +++>>>+[.+] would be three things. First a symbol, +++>>>+, then a vector holding the symbol .+
18:08	RedNifre	,(+ 1 #_ ++>><<[+.]-- 1 )
18:08	clojurebot	#error {\n :cause "+."\n :via\n [{:type clojure.lang.Compiler$CompilerException\n :message "java.lang.ClassNotFoundException: +., compiling:(NO_SOURCE_PATH:0:0)"\n :at [clojure.lang.Compiler analyze "Compiler.java" 6688]}\n {:type java.lang.ClassNotFoundException\n :message "+."\n :at [java.net.URLClassLoader$1 run "URLClassLoader.java" 366]}]\n :trace\n [[java.net.URLClassLoader$1 run "U...
18:09	TEttinger	lodin-: no, . isn't allowed in symbol names IIRC
18:09	RedNifre	okay, so inline bf would be impossible because it uses [ ] for loops.
18:09	TEttinger	,(defn a.b 1)
18:09	clojurebot	#error {\n :cause "Parameter declaration \"1\" should be a vector"\n :via\n [{:type java.lang.IllegalArgumentException\n :message "Parameter declaration \"1\" should be a vector"\n :at [clojure.core$assert_valid_fdecl$fn__7207 invoke "core.clj" 7187]}]\n :trace\n [[clojure.core$assert_valid_fdecl$fn__7207 invoke "core.clj" 7187]\n [clojure.core$map$fn__4785 invoke "core.clj" 2646]\n [clojure...
18:09	TEttinger	,(def a.b 1)
18:09	clojurebot	#'sandbox/a.b
18:09	TEttinger	oh nvm
18:09	TEttinger	,a.b
18:09	clojurebot	#error {\n :cause "a.b"\n :via\n [{:type clojure.lang.Compiler$CompilerException\n :message "java.lang.ClassNotFoundException: a.b, compiling:(NO_SOURCE_PATH:0:0)"\n :at [clojure.lang.Compiler analyze "Compiler.java" 6688]}\n {:type java.lang.ClassNotFoundException\n :message "a.b"\n :at [java.net.URLClassLoader$1 run "URLClassLoader.java" 366]}]\n :trace\n [[java.net.URLClassLoader$1 run...
18:09	TEttinger	ah ok
18:09	justin_smith	RedNifre: as lodin- said that's three forms
18:09	TEttinger	it "allows" infix dot
18:09	TEttinger	but not really
18:10	justin_smith	,(+ 1 #_#_#_ ++>><<[+.]-- 1 ) ; RedNifre
18:10	clojurebot	2
18:10	justin_smith	one #_ per form
18:10	TEttinger	nice trick, justin_smith
18:11	rotcev	so what is the difference between ` and '
18:12	TEttinger	RedNifre: this type of thing is a good use for just using a string as a sequence of chars, since BF is all one-char operators anyway right?
18:12	RedNifre	hm, so macros would make it trivial to write something like Haskell's do-notation...
18:12	TEttinger	rotcev: I really liked brave clojure's walk through that stuff
18:12	lodin-	RedNifre: And it has been done, kind of.
18:12	rotcev	kk
18:12	justin_smith	RedNifre: we do have monad libs, I don't know how far they go syntax wise though
18:13	TEttinger	http://www.braveclojure.com/writing-macros/
18:13	lodin-	justin_smith: I've seen one library that goes pretty far in the Haskell direction, even using <- to bind.
18:14	justin_smith	lodin-: fascinating
18:14	Glenjamin	http://www.leonardoborges.com/writings/2012/12/08/monads-in-small-bites-part-iv-monads/ appears to have something like do notation
18:15	lodin-	justin_smith: It looks pretty alien in Clojure code though.
18:17	RedNifre	Well, in Haskell the problem was that you had nested lambdas i.e. (bind (getSomething) (fn [something] (bind (process something) (fn [another-thing]...))))))) and do-notation turns that into (monadic-do (<- something getSomething) (<- another-thing process something) ...)
18:17	RedNifre	Okay, I think I now see the value of macros :)
18:18	lodin-	RedNifre: :-)
18:29	lodin-	RedNifre: The same nesting would occur in Clojure, but there's no IO monad in Clojure, everything is Maybe (can be nil), and list has it's own do-notation in disguise (the for macro). And let is ordered and allows rebinding, so it is OK to do (let [state (init-state 5), [state v] (get state), state (put state 3)] ...).
18:32	RedNifre	lodin- Well, I'm not sure, couldn't it be done without nesting? Let me write an example...
18:32	lodin-	RedNifre: What I'm saying is that monads are treated case by case.
18:33	lodin-	RedNifre: Not if you want a bind operation and code that would do the same as you Haskell example.
18:34	RedNifre	lodin- I wrote an example, would it be possible to write a macro that turns the second code into the first?: http://pastebin.com/PRz2UAEV
18:34	clojurebot	No entiendo
18:34	lodin-	RedNifre: Monads are less useful in Clojure though since you can't infer which return to use, hence case by case.
18:34	lodin-	RedNifre: Of course, see the link given by Glenjamin above.
18:35	RedNifre	In my example, if I used some promise library that came with that "then" function, could I write that macro just for that one case?
18:35	RedNifre	ah, I somehow missed that link. one sec.
18:37	lodin-	RedNifre: I mean that without using a macro (i.e. introducing do notation in Clojure), the Clojure code would have the same problem.
18:37	lodin-	RedNifre: It's just like justin_smith said, the benefit of macros is that you don't need a language update to provide it, you only need a library.
18:38	RedNifre	Ah, okay, then I understand what you mean.
18:39	RedNifre	Well, it's getting late. Thank you all for your help, good night/day/etc.!
18:47	justin_smith	so I found this twitter account that just posts random pictures from unprotected webcam feeds, and this post it just made is basically me rn https://twitter.com/FFD8FFDB/status/696117413931315200
19:11	noncom\|2	what do you think about scala, people? i have heard that clojure and scala do complement each other.. what are your thoughts?
19:11	noncom\|2	(note: i've been 2.5 years scala, and now i'm 2.5 years of clojure)
19:12	noncom\|2	i am looking at the messages that i still occasionally receive from scala mailing list and stuff... and they seem soo contrived and convoluted :/
19:12	justin_smith	noncom\|2: I wish it was feasible to write individual things in scala then use them via clojure, but it seems like scala is hard to use from other jvm langs
19:12	noncom\|2	of course, much of this comes because of the type system and stuff..
19:13	justin_smith	noncom\|2: or, maybe I'm misinformed and that is actually a straightforward thing to do?
19:13	noncom\|2	hmmm i am not really sure about that.
19:13	noncom\|2	WOW https://t6.github.io/from-scala/
19:14	noncom\|2	well, i guess i understand - scala is ALL about syntax sugar... and when you deal with what this sugar resolves to.. here comes the pains
19:14	noncom\|2	but this lib seems ilke a bridge..
19:15	noncom\|2	well, one more issue i see, is that scala compiler is a sooooo demanding machine..
19:15	noncom\|2	it can drain all your computer resources for just barely printing several symbols inside some of the sugared clauses
19:16	noncom\|2	i remember typing hell instead some pattern-matched json destructor.. i was literally getting 1 char in 1-2 seconds or so
19:16	noncom\|2	(the presentation compiler i mean here, the class one might be heavier but runs once in a while)
19:17	noncom\|2	s/instead/inside
19:17	noncom\|2	eh.. sleepy
19:20	noncom\|2	justin_smith: could you maybe answer a web-specific question? i have a login form made with cljs+bootstrap.. how do i enable password saving in it?
19:21	justin_smith	noncom\|2: the way I handle that is not create the login page with cljs - that way I'm not sending the full app to a user that isn't logged in
19:22	justin_smith	side effect is normal plain old html login page where the browser save-this-password just works
19:22	noncom\|2	hmmm, interesting
19:22	justin_smith	noncom\|2: so the flow is - plain html login, if login succeeds redirect to the single page app and send them all the js etc.
19:23	noncom\|2	ok, i got it.. heh, i'll have to rewrite this bunch of stuff this way... but do you maybe know, how does the browser distinguish?
19:23	justin_smith	noncom\|2: I'm sure there is a way to make the browser save passwords in a react app, but this is why I haven't had to figure that out
19:23	noncom\|2	ah
19:23	noncom\|2	well okay
19:24	justin_smith	noncom\|2: but your case might be different - I have a webapp as a service, so it makes sense not to send the js until they auth
19:24	justin_smith	that makes the auth questions in the server side much simpler
19:25	noncom\|2	justin_smith: in my case it makes sense too. i just did not design it the way you did - the login form is a part of the jsapp. i think your way is more correct and i have to change to it. but it may be not as easy task as i expected, but certainlyk doable
19:27	noncom\|2	justin_smith: eh, just FYO: http://timothy.userapp.io/post/63412334209/form-autocomplete-and-remember-password-with another html/js hell there. i am certainly taking up your way. thanks for the hint!
19:27	justin_smith	noncom\|2: nice to know I dodged that bullet
20:04	justin_smith	lol http://www.foaas.com/
20:07	TEttinger	oh my god Ballmer
20:07	justin_smith	lol
20:08	justin_smith	TEttinger: oh that's awesome I hadn't gotten to that one yet
20:12	justin_smith	TEttinger: https://www.refheap.com/114550
20:13	justin_smith	I know that in the real world there is no such rivalry
20:16	TEttinger	nice
20:18	visof	,(partition 2 1 [1 2 3 4 5 6])
20:18	clojurebot	((1 2) (2 3) (3 4) (4 5) (5 6))
20:19	visof	,(map (fn [xs] (first xs)) (partition 2 1 [1 2 3 4 5 6]))
20:19	clojurebot	(1 2 3 4 5)
20:20	justin_smith	,(map first (partition 2 1 [1 2 3 4 5 6])) ; (fn [xs] (first xs)) is a weird way to write first
20:20	clojurebot	(1 2 3 4 5)
20:21	visof	justin_smith: yeah that's neater, but fn i'm planning to do more complex things than first
20:22	justin_smith	k
20:26	amalloy	speaking of weird ways to write a thing, i recently fixed a bunch of tests that looked like: (is (= true (every? true? (map #(f x %) ys))))
20:26	justin_smith	so with partition 2 1, the first element will only show up once, as the first element of the first pair, and the last will also only show up once, and the last element of the last pair
20:26	amalloy	a poor way to write (is (every? #(f x %) ys))
20:27	justin_smith	amalloy: wow, double whammy there
20:29	justin_smith	(boolean (is (= true (boolean (every? true? (doall (map #(boolean (f x %)) (seq ys)))))))) ; ftw
20:30	justin_smith	no, justin_smith, there is no winning this game and there is always a way to add silly complexity
20:32	justin_smith	oh man - cljs : (inc :1) => ":11"
20:33	justin_smith	I mean you deserve it if you make a terrible keyword like :1, but wow that's gross
21:40	Bronsa	justin_smith: wow :/
21:54	kenrestivo	justin_smith: ugh
23:26	rhg135	that's... disturbing