#clojure – 2014-08-02

2014-08-02

03:38	dazone	Hello 안녕하세요
05:06	blunte	? given a record with fields :a, :b, and :c, how can I retrieve the values for a list/vec of keys such as (:a :c)?
05:07	arrdem	&(map (partial get {:a 1 :b 2 :c 3 :d 4}) [:a :b :c])
05:07	lazybot	⇒ (1 2 3)
05:07	blunte	but the operator function in this case is the key name
05:07	blunte	ah let's see
05:09	blunte	so "get" is what I didn't know about. that brings me to another question. Is there documentation that shows a comprehensive list of operations for a given type/thing? Like if I look up records in clojure, I would like to see not only details on how to construct, but also various ways of interacting with that thing
05:09	blunte	arrdem: thanks, by the way :)
05:10	blunte	with "get" as example, I hadn't seen that yet. All the info I see shows (:keyname my-record)
05:11	arrdem	http://clojure.org/data_structures#Data%20Structures-Keywords
05:13	blunte	ah ha, my failure at reading then :). Thanks again
05:13	arrdem	np
05:16	TEttinger	there's also less-comprehensive docs (but organized well, and with examples) at clojuredocs
05:16	TEttinger	http://clojuredocs.org/quickref/Clojure%20Core
05:16	TEttinger	it's somewhat out-of-date, but the core language is all there. clojuredocs is stuck on version 1.3...
05:17	arrdem	http://jafingerhut.github.io/cheatsheet/grimoire/cheatsheet-tiptip-cdocs-summary.html
05:19	blunte	great, I'll take a look at both
05:20	TEttinger	arrdem, what version is that? I see no reduced
05:21	arrdem	TEttinger: latest. huh. looks like there isn't reduced at all...
05:27	Glenjamin	did the cheatsheet used to have reduced on it?
05:28	Glenjamin	oo, the "Examples" headings in grimoire don't check the :added metadata
05:29	arrdem	Glenjamin: hum?
05:30	Glenjamin	http://grimoire.arrdem.com/1.6.0/clojure.core/reduced has an empty heading for 1.4, but :added says 1.5
05:30	arrdem	Glenjamin: oh... you're saying it should 404 for 1.4.0?
05:31	arrdem	derp
05:31	arrdem	gotcha
05:31	Glenjamin	it does 404 (which is blank), but there also shouldn't be an "Examples from Clojure 1.4.0" section
05:32	arrdem	yeah... thinking about how to address that.
05:32	Glenjamin	just about to update my PR, the contributing.md with the notes on how to syntax highlight seem to have gone awol?
05:32	arrdem	http://grimoire.arrdem.com/contributing
05:33	Glenjamin	ah, the readme links to http://grimoire.arrdem.com/contributing/ which 404s
05:34	arrdem	so if you want to add an example for clojure.core/foo, just go to the page, click add example, choose a random filename (it totally doesn't matter) and paste in a REPL session. that's it.
05:34	arrdem	there's no longer any markup required
05:34	Glenjamin	oh, neat
05:34	arrdem	yeah that was the big point of 0.3.0
05:34	arrdem	get rid of the markup requirement and make each example its own file
05:35	Glenjamin	i think the "contribute an example!" links are missing /resources/
05:35	arrdem	fucking really...
05:35	arrdem	gah
05:36	TEttinger	thanks for contributing to the docs, Glenjamin, arrdem
05:36	blunte	I second that
05:40	arrdem	okay Glenjamin what was the other one...
05:40	arrdem	oh. right. :added
05:40	arrdem	also real 404 fails...
05:45	arrdem	okay... the version range thing I'll fix some other time
05:48	arrdem	Glenjamin: hotfix'd
05:48	Glenjamin	cheers
05:48	arrdem	ugh that's embarasing
05:49	arrdem	<3 patches against develop
05:50	arrdem	another reason for 0.3.0... lets me be more of a git-flow nazi
05:50	arrdem	Glenjamin: thanks for the pr!
08:19	vdmit11	Hi folks. I have a Java array of objects of non-primitive types. The problem is the "aget" seems to be slow because of the reflection. Can I provide type hints for non-primitive arrays? Or perhaps can I transform the array into something else where I can provide hints?
08:22	vdmit11	The array is created only once at program startup, but then it is may be accessed a million times (literally), so I would like to optimize "get" perhaps in cost of transforming the array into another data structure.
08:22	Bronsa	vdmit11: aget requires reflection only if used as a HOF
08:23	Bronsa	,(set! warn-on-reflection true)
08:23	clojurebot	#<IllegalStateException java.lang.IllegalStateException: Can't change/establish root binding of: warn-on-reflection with set>
08:23	Bronsa	shush
08:23	Bronsa	,warn-on-reflection
08:23	clojurebot	false
08:23	Bronsa	vdmit11: http://sprunge.us/gDPZ?clj
08:24	Bronsa	you just need to type-hint the return value of the aget since aget will return an Object
08:29	vdmit11	Bronsa: http://pastebin.com/AWuCZYqU - how about this?
08:29	vdmit11	why doesn't it work
08:30	Bronsa	vdmit11: hint array with ^objects
08:31	Bronsa	(aget ^objects array 0)
08:32	Bronsa	vdmit11: clojure only has local type inference you need to explicitely tag vars
08:33	vdmit11	Bronsa: thanks
08:33	Bronsa	vdmit11: if you have lots of aget calls on that var you can tag directly the var rather than tag it at each invocation site
08:33	Bronsa	(def ^{:tag 'objects} array ..)
08:34	Bronsa	vdmit11: np
09:00	Fare	so, I'm starting to have a collection of small-time utilities
09:00	Fare	is there a place to contribute them to?
09:05	hyPiRion	Fare: https://github.com/weavejester/medley or https://github.com/flatland/useful
09:05	Fare	thanks!
09:16	Fare	useful has lots of good stuff
09:16	Fare	it's a bit chunky, though
09:17	Fare	(inc hyPiRion)
09:17	lazybot	⇒ 41
09:17	hyPiRion	Fare: right, it's a huge chunk of functions – it's not necessarily the thing you want
09:18	hyPiRion	I just heard "collection of small-time utilities" and took what I had at the top of my head
09:19	Fare	ok, so does map always return a list as per list? ?
09:20	Fare	apparently not.
09:20	Fare	how do I make it so?
09:21	hyPiRion	map always return a (possibly chunked) lazy-seq
09:21	Fare	with (into () ...)
09:22	hyPiRion	Fare: that reverses the order though. perhaps (apply list (map ...)) works, but think about why you want it to be a list in the first place
09:22	hyPiRion	it might be that persistent vectors is fine for the job at hadn
09:22	hyPiRion	*hand
09:24	Fare	is it OK to have macros return lazy-seq's?
09:24	Fare	when I analyze source code, how do I distinguish between list and vector?
09:24	Fare	or is that vector and anything-but-vector?
09:26	hyPiRion	Fare: mmm, right, I understand your concern. Generally you'd use seq? for list-like things, vector? for vectors, map? for maps, set? for sets
09:26	hyPiRion	no problem with emitting lazy seqs from macros as far as I know
09:27	Fare	apparently, a vector is not a seq?
09:27	Fare	interesting
09:28	hyPiRion	Fare: A vector is sequential, but not a seq in and by it self
09:29	hyPiRion	I tend to think of seqs as things which wraps what it contains in parens
09:30	visof	hi
09:30	visof	is this conversion right? https://www.refheap.com/88832
09:31	visof	please anybody help
09:31	hyPiRion	visof: yes, that seems to look right
09:31	visof	hyPiRion: i got this error: java.lang.IllegalArgumentException: No matching field found: execute for class com.orientechnologies.orient.graph.gremlin.OCommandGremlin
09:32	hyPiRion	boo
09:33	visof	hyPiRion: check this http://www.massapi.com/class/com/orientechnologies/orient/graph/gremlin/OCommandGremlin.java.html check the first example
09:34	hyPiRion	visof: ah
09:34	visof	hyPiRion: ?
09:36	hyPiRion	could you try (. (.command db (OCommandGremlin. "g.V[0..10]")) (execute)) instead?
09:36	hyPiRion	I think (.. db (command (OCommandGremlin. "g.V[0..10]")) (execute)) should be the equivalent statement.
09:36	hyPiRion	an equivalent*
09:37	visof	hyPiRion: what is the difference?
09:41	hyPiRion	visof: (.a x) expands to (. x a), which may translated to a field lookup, whereas (. x (a)) is always a method call. Not sure if that solves your original problem, but it should make it explicit for the compiler that you're referring to a method
09:41	hyPiRion	that being said, I've not done a lot of work with method calls, so I may be wrong
09:44	visof_	hyPiRion: are you there
09:44	hyPiRion	yes
09:44	visof_	hyPiRion: i have tested both with the same error
09:48	visof_	error: No matching method found: execute for class com.tinkerpop.blueprints.impls.orient.OrientGraphCommand and http://www.tinkerpop.com/docs/javadocs/blueprints/2.4.0/com/tinkerpop/blueprints/impls/orient/OrientGraphCommand.html tell there is execute method for this class
09:48	visof_	can anybody help in this?
09:49	pyrtsa	visof_, hyPiRion: Is `execute` a variadic method? I.e. `execute(Object... args)`? In that case, you'd need to call it with another argument, an empty `(object-array [])`.
09:49	hyPiRion	visof_: oh, you're trying to call a vararg method?
09:49	hyPiRion	pyrtsa: yeah, I just realised ;_;
09:50	visof_	pyrtsa: so i need to call it with (.execute (...) []) ?
09:50	pyrtsa	Googled it. :)
09:50	hyPiRion	visof_: (.. db (command (OCommandGremlin. "g.V[0..10]")) (execute (object-array [])) should work
09:50	pyrtsa	That. ^
09:50	visof_	pyrtsa: what google results you get ?
09:51	pyrtsa	visof_: Well, just googled to find out what the method signature of execute() was. You should be aware of these issues when doing Java interop
09:52	visof_	pyrtsa: hyPiRion thanks guys
09:54	visof_	got another error: java.lang.IllegalAccessError: class com.tinkerpop.blueprints.impls.orient.OrientGraphQuery$OrientGraphQueryIterable cannot access its superclass com.tinkerpop.blueprints.util.DefaultGraphQuery$DefaultGraphQueryIterable
11:00	mdo_	hello
11:02	l3dx	anyone using liberator? I can't figure out how to set the Location header after doing a successful POST (201)
11:07	tcsavage	l3dx: (ring-response {:headers {"Location" "http://urlwhatever"}}) should do the trick
11:07	tcsavage	it's a bit messy to use ring directly but it seems like the easiest way to do it
11:08	vsj_	Hello, I'm still new to Clojure and I've a question about nested vectors (output of instaparse)
11:08	vsj_	Here's the example:
11:09	vsj_	[[:t [:a 1] [:b [[:e 4] [:f 5]]] [:c 3]] [:t [:a 4] [:b [[:e 7] [:f 8]]] [:c 6]]]
11:09	vsj_	I'd like to extract the values related to :f anc :c, ie expected output: [5 3] [8 6]
11:09	vsj_	What is the best way to do this? I played around with zippers, walk, etc. but it seems to complex
11:10	vsj_	Thanks in advance
11:10	tcsavage	is there a reason why you're using nested vectors [:a [...]] rather than a map? {:a [...]}
11:11	vsj_	It's instaparse output
11:11	l3dx	tcsavage: thanks
11:12	vsj_	To be more accurate, its a seq with nested vectors, like this ([:t [:a 1] [:b [[:e 4] [:f 5]]] [:c 3]] [:t [:a 4] [:b [[:e 7] [:f 8]]] [:c 6]])
11:13	l3dx	I'm a bit surprised that it isn't handled by liberator. thought that was kind of rest/hypermedia-101 :) (but I don't know. I'm kind of a newbie when it comes to this topic)
11:14	ambroseb_	vsj_: try changing the output format https://github.com/Engelberg/instaparse#output-format
11:15	tcsavage	l3dx: there are a few things liberator doesn't handle too well, but it's pretty good as the basics
11:20	l3dx	tcsavage: yes it seems very promising
11:20	vsj_	the other output format turns it into somekind of dict, but much more complicated than it needs to be, with things like { :tag :t :content {:tag :a :content 1 etc
11:21	vsj_	maybe turn the nested vector into a nested dict ? would that make it easier?
11:22	vsj_	sorry, I mean map, I come from the Python-world :)
11:25	tcsavage	l3dx: liberator is awesome. We've been using it at work for a few months now and I can't imagine writing restful services any other way
11:48	l3dx	tcsavage: seems like there is some handling of it (201 location) https://github.com/clojure-liberator/liberator/blob/master/src/liberator/core.clj#L166
11:48	l3dx	I'm unable to figure out how to do it without hard coding the :location of the resource
11:48	l3dx	so I'll just stick with ring-response for now
11:48	l3dx	:)
11:50	tcsavage	l3dx: oh interesting. I didn't know that
11:50	tcsavage	it looks like it will look in the context first though
11:55	l3dx	oh, so I could probably just do (assoc ctx :location "http://whatever") in :post! then
11:56	l3dx	well, at least it is working :)
11:59	tcsavage	or just return {:location "http://whatever"} from :post! (it'll automatically merge it into ctx)
12:01	l3dx	ah
12:20	vdmit11	Hi folks, is there a way to get a function with two arities, one is [foo bar baz] and another is [& {:keys [foo bar baz]}]?
12:21	opqdonut	vdmit11: not easily, but you can always just define it with [& args] and parse args "manually"
12:23	vdmit11	Yea, I just thought that perhaps I don't need to do that manually
12:23	jeremyheiler	,(fn state".
12:23	clojurebot	#<RuntimeException java.lang.RuntimeException: EOF while reading string>
12:23	jeremyheiler	,(fn ([a b c] :three) ([& args] :many))
12:23	clojurebot	#<CompilerException java.lang.RuntimeException: Can't have fixed arity function with more params than variadic function, compiling:(NO_SOURCE_PATH:0:0)>
12:25	opqdonut	vdmit11: frankly, I'd just give the two arities different names
12:25	opqdonut	vdmit11: myfunction and myfunction-kw perhaps
12:38	gfredericks	vdmit11: those two definitions are just barely not ambiguous ;-)
13:39	ticking	the "hello-cljsc" tutorial good overview on how to call the clojurescript compiler from clojure, however I was wondering if there is any support for referring other namespaces (or is this handled by each tool individually?)
13:39	ticking	*provides
14:12	l3dx	tcsavage: (or anyone else) am I supposed to update :new? from within put! ? seems like the function of :new? is evaluated after put!
14:15	tcsavage	put! is where you perform the action of creating or updating. You can store a value in the context and retrive it in new? to choose the return value
14:17	tcsavage	so for example, put! could return {:created-records true/false} and your :new? could be the function (fn [ctx] (:created-records ctx))
14:17	tcsavage	(I hope i'm answering your question correctly)
14:18	l3dx	yes you do! :)
14:18	l3dx	thank you
14:19	l3dx	I didn't think of that. I tried checking if the element was part of a collection (just playing around) but it always was after the put! function completed
14:30	dnolen_	ticking: what are you asking?
14:31	ticking	what is the best way to compile entire clojurescript expressions, including the loading of other libraries/namespaces, from within clojure?
14:34	ticking	dnolen_: It seems that everything is pretty straight forward except for refer, require, require-macros and use.
14:34	dnolen_	ticking: oh, you have cljs.analyzer/analyze-file and cljs.compiler/compile-file
14:35	dnolen_	ticking: not many people go this route so not sure how well using the CLJS compilation pipeline works when doing it this way
14:39	ticking	dnolen_: yeah I'll see how far I get :) thanks, I thought it would be nice to have clojurescript preview support in gorilla repl so that one can just write (cljs '(some cljs code)) to get a prototype inlined
14:40	tmarble	dnolen_: I found a necessary change to the basic tutorial as a result of the React upgrade
14:40	tmarble	https://github.com/facebook/react/issues/1920
14:41	tmarble	old - :onKeyPress #(when (== (.-keyCode %) 13) (commit-change text owner))
14:41	tmarble	new - :onKeyDown #(when (= (.-key %) "Enter") (commit-change text owner))
14:41	dnolen_	tmarble: great, please update
14:42	tmarble	ok, will do
14:42	tmarble	in trying to understand the react event (passed in as an arg) I tried (naively) to do this
14:42	tmarble	in the above method
14:42	tmarble	(println (.stringify js/JSON %))
14:42	tmarble	but that didn't work (not sure why)
14:43	dnolen_	tmarble: if the JS object has cycles
14:44	tmarble	d'oh!
14:53	bryanmaass	Does anyone have a bunch of experience with enlive?
15:03	ticking	dnolen_: Does the compiler delegate dependency management entirely to the tools calling it?
15:07	dnolen_	ticking: dependency stuff happens in cljs.closure
15:07	dnolen_	ticking: and yes it's hand rolled and deal with a lot of cases
15:09	arohner	while we're on the subject of cljs compilation, is there a cider-like workflow for cljs? I really like that C-c C-k puts exceptions in my face when compiling clj code
15:09	arohner	where 'cljsbuild auto dev' means I have to switch over to the tab to see if anything happened
15:13	LauJensen	Hey - I've just tried removing my old packages, installing cider in emacs and lein and everything works great, except for one thing. When I open a .clj file, Clojure-Mode activates automatically and then I manually have to run M-x cider-mode. Any idea what gives?
15:13	LauJensen	My auto-mode-alist has this entry ("//.clj$" . cider-mode)
15:15	expez	LauJensen: automode-alist is used to activate major modes
15:15	expez	cider is a minor-mode
15:15	dnolen_	arohner: I'm not aware of something like that though it's really just a matter of someone spending some time on it
15:15	dnolen_	arohner: if there's anything missing in CLJS to make it work - will happily take patches
15:16	LauJensen	expez: Ah okay. How how to attach a minor mode?
15:16	LauJensen	First 'how', should have been a 'So'
15:17	expez	LauJensen: (add-hook 'clojure-mode-hook #'cider-mode) should do it
15:19	expez	alternatively (add-hook 'clojure-mode-hook #'my-clojure-mode-hook) and put (cider-mode 1) when you create the function my-clojure-mode-hook in which you do everything relevant to clojure-mode (turn on cider-mode, turn on company-mode, turn on paredit etc etc)
15:19	expez	there's a #clojure-emacs channel where you can ask more questions about clojure development in emacs
15:24	michaelr`	hello
15:31	vdmit11	Is there a reader macro that evaluates a form at the read time. Common Lisp has the "#." and I can do something like "#.(+ 1 2)" which is evaluated to "3" by the reader. Is there something like this in Clojure?
15:32	bbloom_	,(quote #=(+ 2 2))
15:32	clojurebot	#<RuntimeException java.lang.RuntimeException: EvalReader not allowed when read-eval is false.>
15:32	bbloom_	,(set! read-eval true)
15:32	clojurebot	true
15:32	bbloom_	,(quote #=(+ 2 2))
15:32	clojurebot	#<RuntimeException java.lang.RuntimeException: EvalReader not allowed when read-eval is false.>
15:32	bbloom_	ah, oh well
15:32	bbloom_	anyway, try that locally
15:32	bbloom_	usual security caveats apply
15:36	vdmit11	Yea, thanks, but it seems it doesn't solve my problem, because I forgot that it involves local lexical bindings and the reader could not understand them.
15:36	LauJensen	expez: That did the trick, thanks a bunch
15:37	bbloom_	vdmit11: rewind: what are you trying to do?
15:39	vdmit11	Let me define a problem. I use "case", but I would like to use numbers as clauses. I don't want to hardcode them, so I use "let" to bind some locals to numbers, but I can't use them as case's clauses, so I thought perhaps I can evaluate them before macro expansion stage.
15:41	bbloom_	vdmit11: unless you've measured & know you have a performance issue, just use condp =
15:41	vdmit11	well, I have the performance issue and I measured it :)
15:42	vdmit11	condp seems to be slow, even slower than cond with a bunch of comparisons
15:43	vdmit11	but case with hardcoded numbers is much faster
15:43	bbloom_	vdmit11: you don't want to hard code them b/c they vary at runtime, or because you want them to have symbolic names?
15:44	vdmit11	They don't vary, these numbers are enumerations used in a binary protocol. I just would like to give them names to make code readable.
15:44	bbloom_	so then why doesn't #=var-name solve your problem?
15:46	bbloom_	or better yet, just write a simple macro for this
15:46	bbloom_	where you just var-get the enumeration values by name
15:47	bbloom_	anyway, some macro for your needs can just produce the case expression you want
15:47	bbloom_	shouldn't be a problem
15:48	vdmit11	(def one 1) #=one -> ClassNotFoundException one
15:48	vdmit11	why?
15:48	clojurebot	why is the ram gone is <reply>I blame UTF-16. http://www.tumblr.com/tagged/but-why-is-the-ram-gone
15:48	bbloom_	vdmit11: because of the fact that #= isn't a documented feature, it's a broken hack for a particular use case rich/stu had however long ago
15:48	bbloom_	you need to do #(identity one)
15:48	bbloom_	i mean: #=(identity one)
15:49	bbloom_	but in this case, a regular macro will solve your problem
15:49	vdmit11	Yea, I'd like the macro too, thanks
15:51	dbushenko	hi all!
15:51	vdmit11	(defmacro four [] 4) (case 4 (four) (print "four")) -> IllegalArgumentException No matching clause: 4
15:51	vdmit11	I guess I miss something
15:51	dbushenko	lets say I'm running 'lein test' -- I need to select different db connection URL. How would I learn that I'm in testing mode?
15:52	bbloom_	vdmit11: case does not macro expand it's arguments
15:52	bbloom_	vdmit11: or evaluate them in any way for that matter
15:52	bbloom_	vdmit11: i meant your own macro that returns a case expression
15:52	vdmit11	oh
15:52	vdmit11	ok
15:52	vdmit11	thanks
15:53	bbloom_	(defmacro var-case [expr & clauses] `(case ~expr ...))
15:53	bbloom_	where in the ... you look up the vars
15:57	vdmit11	btw, (def one 1) (case 1 #=(identity one) "foo") -> No matching clause: 1
15:58	bbloom_	vdmit11: shrug not sure about that
15:58	bbloom_	but anyway, just do the var-case or whatever
15:59	Fare	is there an implementation of delimited continuations for clojure?
15:59	vdmit11	yea, I'll do the macro, but I just checked another approach for test
15:59	bbloom_	Fare: not any one that has dynamic extent
16:00	Fare	that might or might not be enough to implement python generators.
16:01	bbloom_	Fare: generators are shallow, so lexical extent shoudl be good enough
16:01	Fare	yes
16:02	bbloom_	Fare: core.async's internals are the most robust finite state machine transform available
16:02	bbloom_	Fare: rich mentioned some interest in incorporating that stuff for generators potentially in to the mainline compiler
16:02	Bronsa	I toyed with delimc a while ago, it's broken with records IIRC
16:03	Fare	broken with records? How do records interact with continuations??
16:03	lazybot	Fare: What are you, crazy? Of course not!
16:04	Bronsa	Fare: the cps rewriter wasn't handling them correctly
16:04	bbloom_	Fare: evaluation of record literals
16:04	Fare	I don't imagine what's magic about them that requires special treatment.
16:05	Fare	(are there record literals? I thought it was (->my-record-type arg1 arg2 arg3))
16:07	bbloom_	,(defrecord Point [x y])
16:07	clojurebot	sandbox.Point
16:07	bbloom_	,(Point. 5 10)
16:07	clojurebot	#sandbox.Point{:x 5, :y 10}
16:07	bbloom_	,(->Point 5 10)
16:07	clojurebot	#sandbox.Point{:x 5, :y 10}
16:07	bbloom_	,#sandbox.Point{:x 5, :y 10}
16:07	clojurebot	#<RuntimeException java.lang.RuntimeException: Record construction syntax can only be used when read-eval == true>
16:08	Bronsa	uhm nevermind, it wasn't records that were breaking delimc, it was using a map destructuring in a let
16:09	Fare	oh, makes more sense
16:09	bbloom_	user=> #user.Point{:x 5, :y (+ 5 10)}
16:09	bbloom_	#user.Point{:x 5 :y (+ 5 10)}
16:09	bbloom_	note how the record does not evaluate it's data
16:09	Bronsa	I remember a "create" call was being inserted somewhere in the transformed code though I have no idea where that would come from
16:09	bbloom_	compare to maps, which would return 5 and 15
16:10	Fare	bbloom_, sounds evil and non-orthogonal to me
16:10	Fare	,`#user.Point{:x 5, :y ~(+ 5 10)}
16:10	clojurebot	#<RuntimeException java.lang.RuntimeException: Record construction syntax can only be used when read-eval == true>
16:11	Fare	,(set! read-eval true)
16:11	clojurebot	true
16:11	Fare	,`#user.Point{:x 5, :y ~(+ 5 10)}
16:11	clojurebot	#<RuntimeException java.lang.RuntimeException: Record construction syntax can only be used when read-eval == true>
16:12	Fare	having implemented (and painfully debugged) a ` for CL, I always hated how it did or didn't interact with vector or structure syntax.
16:12	bbloom_	Fare: read-eval is a security issue, so clojurebot blocks it, even tho i'm pretty sure you can turn it on w/ some hackery & it's not that big a security issue b/c of sandboxing etc
16:12	bbloom_	also the 'user namespace is from my local repl
16:12	bbloom_	it's the 'sandbox namespace here in irc
16:13	bbloom_	i've gone back and forth on record evaluation behavior
16:13	bbloom_	on one hand, we've already got the factory functions for applicative-order evaluation
16:13	Fare	and at my repl, it expands to: #user.Point{:x 5, :y (clojure.core/unquote (+ 5 10))}
16:13	Fare	yuck
16:13	bbloom_	but on the other hand, so does maps have hash-map etc
16:22	arohner	someone needs to get on ClojureSwift, so I can go back to working in a good language
16:23	Fare	arohner, you're forced to use Swift?
16:23	ben_vulpes	is there any implicit retraction for maps in datomic, similar to the d/transact [{...}] ?
16:23	arohner	Fare: forced to osx native, yes. and Swift >> ObjC
16:24	arohner	Fare: writing an osx native app that talks to a Clojure server, so it's not all bad :-)
16:24	Fare	I suppose Swift is also for iOS
16:24	michaelr525	hey
16:24	Fare	how does conditional compilation happen to distinguish clj from cljs, clswift ?
16:25	ben_vulpes	i guess dbfn/retractentity...
16:26	arohner	Fare: there are a handful of options, none 'blessed' yet
16:26	arohner	https://github.com/lynaghk/cljx
16:26	arohner	there's another, I don't remember its name
16:26	arohner	but it's quite amazing how much Swift the lang has to anticipate which features you'll want
16:27	arohner	so many special cases compared to lisps
16:27	dnolen_	arohner: cljsbuild has :crossovers built in, though been deprecated by cemerick
16:27	Bronsa	Fare: bbloom_ I feel like `#user.record[~x] returning #user.record[(unquote x)] is probably a bug
16:27	arohner	dnolen_: there's another I'm trying to remember, it assumed you'll write 'mostly' clj, with cljs as the less common case
16:28	bbloom_	Bronsa: no, it's not
16:28	dnolen_	arohner: steve miner also had something based on reader literals
16:29	bbloom_	Bronsa: http://clojure.org/datatypes
16:29	bbloom_	Bronsa: see the defrecord reader support
16:29	Bronsa	bbloom_: I understand why it happens but I feel uneasy about #foo.bar[~x] being equal to `#foo.bar[~x]
16:29	bbloom_	it's documented to leave elements unevaluated
16:29	Fare	bbloom_, a bug in the spec, perhaps?
16:30	michaelr525	dnolen_: om-sync, does it support sending DELETE requests to /collection/id somehow? I've experimented with it a bit and it seems to send the requests just to /collection (the url parameter)..
16:30	dnolen_	michaelr525: om-sync is really still at proof of concept phase, and I'm not actively working on, would take PRs of course
16:30	Bronsa	bbloom_: eh, I guess you're right, there's really no way to make that "work"
16:31	michaelr525	dnolen_: ok, thought so but wasn't sure maybe I'm missing something :)
16:36	vdmit11	Hey folks, sorry if I ask too much stupid questions, but is there a way to use a function before defining it? I'd like when I can read the code from top to bottom and I would like to organize it in this way. In languages like C I can make a bunch of declarations first, then define a top-level function like main() and then define other functions used in main() and so on. Can I do something similar in clojure?
16:37	arohner	,(doc declare)
16:37	clojurebot	"([& names]); defs the supplied var names with no bindings, useful for making forward declarations."
16:37	arohner	vdmit11: that only says that you will define something later, you can't e.g. specify arguments
16:38	arohner	vdmit11: for the most part, it's not very common though. mostly people just declare things in order
16:39	bbloom_	vdmit11: reading top-to-bottom is arguably better or worse than bottom-to-top, but both are better than totally random order
16:40	bbloom_	vdmit11: just get used to define-before-use, which i'd argue is preferable to top-to-bottom reading order :-)
16:41	vdmit11	bbloom_: give me an argument why it is better
16:42	vdmit11	perhaps I wold like to use it
16:42	bbloom_	vdmit11: 1) it's naturally enforced
16:42	bbloom_	2) it mirrors interactive use of the repl to define things
16:43	bbloom_	3) it makes mutual recursion explicit
16:43	arohner	4) it's easier to read top-to-bottom, because you've seen the definition of everything before use
16:44	bbloom_	5) in reality it's not reading top-to-bottom or bottom-to-top, it's reading top-to-bottom-to-top in both cases
16:45	bbloom_	it means your compiler operates on a stream, rather than a batch
16:45	bbloom_	lots of reasons
16:46	bbloom_	Bronsa: Fare: i'm trying to find some discussion of the evaluation behavior of records, but can't find any good history about it
16:46	arohner	vdmit11: understanding lisp compilation model helps a lot
16:47	arohner	vdmit11: the compiler essentially treats .clj files as if you typed it all into the repl
16:47	arohner	rather than a C compiler that works on files
16:47	vdmit11	well, I don't want to organize the code in some way just because the compiler treats them like a stream or because of any other thinks that looks like a technical limitation
16:47	kristof	bbloom_: I think that's just an excuse for babysitting the compiler.
16:48	bbloom_	kristof: disagree
16:48	vdmit11	ok, thanks for the advice anyway
16:48	bbloom_	it means that i can reason about my file as being effectively inside a big (do ...)
16:48	Fare	CL has something horrible: vectors, notated #(foo bar), do NOT evaluate their arguments, yet unquote DOES work inside them. On the other hand, N-dimensional arrays support neither evaluation not unquote. And structures don't even have a standard readable syntax.
16:50	bbloom_	yup :-/
16:50	bbloom_	kristof: vdmit11: the semantics of namespaces & vars are that of mutable maps, which differs from something like racket, for which the compilation unit is a module
16:51	Bronsa	bbloom_: the only reason I can think of why the record literals don't evaluate their args is to avoid complicating the compiler. but I really hope that wasn't the only reason
16:51	bbloom_	Bronsa: why would it complicate the compiler?
16:52	Bronsa	bbloom_: to allow for args evaluation the compiler would need a node for records rather than using ConstExpr as it is now
16:52	kristof	bbloom_: Lisp style has almost always been to define the more abstract functions before the simpler ones. Scheme style is like this, CL style is like this. The JVM simply doesn't allow forward references like that. Wasn't it Michael Fogus who used the same phrase I did when talking about declare?
16:52	Fare	bbloom_, I once designed (but did not implement, for compatibility reasons) a "Meta-Unquote" protocol so that unquote can be generalized to extensible syntax
16:54	bbloom_	Fare: that's interesting. in designs i'm working on, i'm exploring the idea of avoiding quoting all together and instead making evaluation explicit, rather than implicit with explicit quoting
16:54	bbloom_	Fare: John Shutt's thesis on "Kernel" is worth studying
16:54	kristof	bbloom_: Fexprs?
16:54	kristof	Oh, yeah
16:54	bbloom_	kristof: to a first approximation, yes
16:55	Bronsa	kristof: clojure could easily allow implicit forward references of Vars, in fact supporting that would require only a couple of lines to be changed in the compiler. it's a design choice that it doesn't
16:55	bbloom_	kristof: and it's also possible to swipe out types at runtime too, although much more difficult to do so (you need a custom class loader)
16:55	kristof	Something that had a lot of staying power with me was Shutt's sentiment that abstraction is the second derivative of semantics.
16:56	bbloom_	kristof: derivative with respect to what?
16:56	kristof	bbloom_: tokens, I suppose
16:57	bbloom_	not sure i follow
16:57	bbloom_	but i really do prefer the declare-before-use style of clojure
16:57	kristof	bbloom_: What he wrote went something like: expressiveness is how fast you can change what something means through the addition of tokens, and abstractiveness is how fast you can change expressiveness
16:57	bbloom_	although i do think that the batch-style definitions are also useful for a variety of things
16:58	kristof	bbloom_: It's obviously a strained comparison but I think it's slightly intuitive and it was fun to think about. And how fun something is is the most important metric of a concept.
16:58	bbloom_	kristof: i guess i need to re-read http://fexpr.blogspot.com/2013/12/abstractive-power.html
16:59	bbloom_	i do believe in the primacy of syntax, however
16:59	kristof	bbloom_: I think everyone needs to reread it, I'm not going to pretend like I understood more that 3/4 of it
17:08	Fare	bbloom_, one predecessor of Lisp had this too, explicit evaluation
17:08	bbloom_	Fare: prolog uses explicit evaluation
17:09	bbloom_	& Mathematica has LOTS of evaluation control options
17:09	lazybot	java.lang.RuntimeException: Unable to resolve symbol: Mathematica in this context
17:09	bbloom_	(too many maybe)
17:09	bbloom_	the new mathematica 10 has some cool "inactive expressions" thing too
17:09	bbloom_	http://reference.wolfram.com/language/guide/EvaluationControl.html
17:12	Fare	meanwhile I'm bumbling on a stupid python evaluator
17:12	Fare	that, and interfaces between CL and scripting
17:13	Fare	well, at least, the CL scripting thing is done — yay for #!/usr/bin/cl
17:13	csd_	Can someone please tell me what is wrong with this code?
17:13	Fare	csd_: the stars are not aligned
17:13	csd_	#(loop [len 0, acc %] (if (empty acc) len (recur (+ len 1) (rest acc))))
17:14	dbushenko	whats best for migrations in clojure?
17:15	ticking	csd_: you probably mean empty? acc
17:15	arohner	,(doc empty)
17:15	clojurebot	"([coll]); Returns an empty collection of the same category as coll, or nil"
17:15	arohner	,(doc empty?)
17:15	clojurebot	"([coll]); Returns true if coll has no items - same as (not (seq coll)). Please use the idiom (seq x) rather than (not (empty? x))"
17:15	arohner	,(if [] "[] is truthy" "[] is falsey")
17:15	clojurebot	"[] is truthy"
17:15	Fare	I believe Newell's IPL required explicit evaluation of variables
17:16	csd_	ticking: ugg... i spent way too long trying to debug this
17:16	csd_	thanks
17:17	Fare	dbushenko, what kind of migration?
17:18	dbushenko	db migrations
17:18	ticking	dnolen_: it seems that the cljs compiler is very file oriented and heavily relying on side effects through emit, is this done on purpose or did it just evolve that way?
17:18	Fare	from what db to what db?
17:18	dbushenko	Fare, never mind
17:19	Fare	there is a nice tool in CL for migrating stuff to pgsql
17:20	Fare	pgloader
17:24	Fare	how with tools.analyzer do I specify which data or meta-data fields are to be preserved, and which are to be recomputer, or added / removed ?
17:30	Fare	stupid question: markdown, restructured text, etc. — which should I be using?
17:32	bbloom_	Fare: depends on what for
17:32	dnolen_	ticking: on purpose
17:32	bbloom_	Fare: for readmes on github and similar, markdown seems to have won
17:33	dnolen_	ticking: everyone that uses the complier is using cljsbuild and the file oriented stuff is for perf
17:33	bbloom_	dnolen_: i don't use cljsbuild :-P
17:33	ticking	dnolen_: very interesting thanks :)
17:34	technomancy	Fare: depends on whether it's for personal use or optimized for lowest friction from external contributors. (markdown wins on the latter despite being kinda crap)
17:34	dnolen_	bbloom_: heh ok I meant "most"
17:35	bbloom_	i haven't tried this new thing tho, what was it called? just saw something about it
17:36	dnolen_	ticking: and it's like to become more not less reliant on the file system for caching - caching analysis is the next thing I'm going to work on.
17:37	Fare	I want to tweak the cl-launch self-help into a format that I can extract a man page from
17:37	Fare	apparently, pandoc can do that for me.
17:38	technomancy	pandoc is supposed to be pretty fancy =)
17:39	bbloom_	dnolen_: ah, found it https://github.com/bhauman/lein-figwheel
17:39	ticking	dnolen_: too bad ;), being able to embed cljs into hiccup, never leaving a clojure repl, would be pretty cool
17:39	bbloom_	haven't tried that yet
17:39	dnolen_	ticking: you can do that - you just use the existing top level entry points, write your own thing
17:39	dnolen_	s/you just/you just can't
17:40	ticking	dnolen_: yeah I figured the best way to turn quoted clojure structures into js is probably writing a custom repl environment
17:40	ticking	stealing a bit of code from the browser env
17:40	dnolen_	ticking: all the existing gnarliness only happens on the file level entry points - if this isn't true let me know and we can work on fixing.
17:43	ticking	dnolen_: yeah, the most daunting bit is probably proper dependency loading and I
17:43	ticking	can look into the repl code for that, thanks :)
17:47	dnolen_	bbloom_: oh yeah did you see the recent VIM CLJS workflow post? seemed interesting
18:38	swgillespie	hi all, does anyone in here have experience with korma?
18:46	amalloy	~anyone
18:46	clojurebot	anyone is anybody
18:46	amalloy	sigh
18:47	amalloy	~ask
18:47	clojurebot	The Ask To Ask protocol wastes more bandwidth than any version of the Ask protocol, so just ask your question.
18:47	Aim_Here	One of these days, what I'll really want to know is whether someone can help me with thing X
18:48	Aim_Here	I won't care about getting X to work, just a social survey of some IRC channel
18:53	swgillespie	k, never mind
19:00	Fare	pandoc seems to output a pretty lousy man page.
19:00	Fare	:-(
19:10	tmarble	dnolen_: I adapted the Basic Om tutorial: https://github.com/tmarble/om-tut2
19:10	tmarble	this removes IClonable and takes baby steps towards Intermediate (w/o a DB)
19:29	rpaulo	is there anything like lex/yacc in clojure?
19:33	_eric	is there something like using (map vector l1 l2) that continues going until the longest list is done?
19:40	jeremyheiler	rpaulo: you may be interested in instaparse
19:41	rpaulo	ah, looks better than parsley
19:41	dnolen_	_eric: you can concat all the seqs with a repeatedly sentinel, then take-while as long as every value of vector is not the sentinel
19:42	dnolen_	tmarble: cool
19:47	Trieste	Hi, can anybody tell me what's wrong with my version of nth for problem 21 on 4clojure? (fn [coll n] last (take (+ n 1) coll)))
19:48	hyPiRion	Trieste: You're lacking a set of parentheses.
19:48	Trieste	hyPiRion: where?
19:48	hyPiRion	→ (fn [coll n] (last (take (+ n 1) coll)))
19:48	hyPiRion	oh, perhaps you lost the one in front of last, because you have 3 ending ones.
19:49	Trieste	oh! thanks :)
19:49	Trieste	still getting the hang of this
19:50	hyPiRion	Trieste: good luck with the next ones =)
19:52	mthvedt	rpaulo: there is also my favorite parser, https://github.com/mthvedt/clearley
20:40	rpaulo	interesting
21:05	dbyrne	anyone here have experience working with core.typed?