#clojure – 2016-01-21

2016-01-21

00:00	luxbock	felixn_: I don't know Python that well but I think the big difference between transducers and generators is that transducers are source agnostic
00:00	luxbock	i.e. you can re-use the same code with sequences and channels
00:01	luxbock	and any other source that might come up in the future
00:02	baritonehands	so defprotocol for CRUD by id semantics, where one implementation is in memory ref, future implementation is some DB?
00:02	justin_smith	right
00:02	justin_smith	and then you could even have general game-logic code that calls the methods of that protocol
00:03	justin_smith	and if you do it right, that game-logic code can be completely stateless / functional
00:03	felixn_	luxbock: if python had channels, I imagine it could work with that. generators seem to support the same API as transducers, so my thinking is just that they're built with HoF... which makes me "get it", unless what I'm saying is wrong, than I still don't get it XD
00:03	justin_smith	a bunch of functions that take a game, and return the next round of the game
00:04	baritonehands	justin_smith: not too much game logic, just state transitions mostly, and validation
00:04	baritonehands	waiting -> playing -> done
00:04	justin_smith	felixn_: for all X in clojure, X is higher order functions
00:04	justin_smith	baritonehands: your state transitions are what I called logic
00:07	baritonehands	justin_smith: so for actual file organization, what would you recommend?
00:07	baritonehands	where would by protocol and its implementations go, etc.
00:08	justin_smith	state management protocol gets its own namespace, each implementation of that protocol gets its own namespace, all validation and transition functions use the protocol methods but the protocol is the only code shared between any of these
00:09	justin_smith	so validate.clj requires state.clj and calls its methods, sql.clj requires state.clj and implements its methods, ref.clj requires state.clj and implements its methods, state.clj is very small, just defines the protocol. Then a namespace that brings the pieces together and starts all the code.
00:10	baritonehands	justin_smith: does my RESTful api fit into all of this?
00:11	justin_smith	it would be an implementation detail of that last namespace that it serves an API
00:11	felixn_	baritonehands: if you're building an API, is there a need to build turtles all the way down? you could just keep the API code flat and straight forward
00:12	baritonehands	felixn_: The api code is also very generic. If I could reuse CRUD semantics there as well it would help
00:13	baritonehands	felixn_: Current api - https://github.com/baritonehands/avalon/blob/master/src/clj/avalon/api/games.clj
00:13	felixn_	baritonehands: seems like a function that just builds endpoints would be sufficient
00:13	felixn_	you'll drastically cut down on lines of code
00:14	baritonehands	felixn_: defresource is a macro, so I think it would have to use a macro to generate
00:16	justin_smith	baritonehands: my one bit of feedback on that api namespace is that there is code in that namespace that relies of the fact that the game state is in a ref
00:16	justin_smith	otherwise it's an api :)
00:17	baritonehands	justin_smith: I don't think it relies on games being a ref. I only ever call functions in the games namespace. Never reference games ref directly.
00:18	justin_smith	baritonehands: dosync
00:18	baritonehands	ah, yeah, games and people need to be updated in the same transaction
00:18	justin_smith	for sql this would be some transaction holding function instead
00:18	justin_smith	point is, it's a leaked detail
00:19	baritonehands	justin_smith: Yeah, hmm
00:20	justin_smith	if you want the implementation to be abstracted, and for it to handle state with methods owned by the data state, then I'd do the protocol as I mentioned before, and let the protocol methods handle the transaction logic as needed
00:21	baritonehands	justin_smith: so that means the protocol needs a method to create and relate two different references/db entities
00:21	justin_smith	probably, yes
00:28	justin_smith	in fact you could simply not expose the data objects themselves, and just expose unique ids, then you don't need to expose any transaction function at all, the implementation could use transactions as apropriate, implicitly
00:35	neoncontrails	Is there a better way to do this?
00:36	neoncontrails	,(read-string ((comp str str/lower-case) (reduce into #{} '[(:FOO :BAR :BAZ)])))
00:36	clojurebot	#error {\n :cause "No such namespace: str"\n :via\n [{:type clojure.lang.Compiler$CompilerException\n :message "java.lang.RuntimeException: No such namespace: str, compiling:(NO_SOURCE_PATH:0:0)"\n :at [clojure.lang.Compiler analyze "Compiler.java" 6688]}\n {:type java.lang.RuntimeException\n :message "No such namespace: str"\n :at [clojure.lang.Util runtimeException "Util.java" 221]}]\n ...
00:36	neoncontrails	,(read-string ((comp clojure.string clojure.string/lower-case) (reduce into #{} '[(:FOO :BAR :BAZ)])))
00:36	clojurebot	#error {\n :cause "clojure.string"\n :via\n [{:type clojure.lang.Compiler$CompilerException\n :message "java.lang.ClassNotFoundException: clojure.string, compiling:(NO_SOURCE_PATH:0:0)"\n :at [clojure.lang.Compiler analyze "Compiler.java" 6688]}\n {:type java.lang.ClassNotFoundException\n :message "clojure.string"\n :at [java.net.URLClassLoader$1 run "URLClassLoader.java" 366]}]\n :trace\...
00:38	neoncontrails	Hmmm. Not sure how to fix without importing clojure.string. But the expected output is #{:baz :bar :foo}
00:51	baritonehands	justin_smith: How do I reference the memdb implementation where I need it, but only reference the crud protocol?
00:52	baritonehands	(defprotocol CRUD
00:52	baritonehands	(create [entity])
00:52	baritonehands	(get [id])
00:53	baritonehands	(save [id updates])
00:53	baritonehands	(delete [id]))
00:53	baritonehands	,(defn create-db []
00:53	baritonehands	(let [db (ref {})]
00:53	clojurebot	#<RuntimeException java.lang.RuntimeException: EOF while reading>
00:53	baritonehands	(reify CRUD
00:53	baritonehands	(create [entity]
00:53	baritonehands	(let [id (str (java.util.UUID/randomUUID))]
00:53	baritonehands	(dosync (alter db assoc id (assoc entity :id id)))
00:54	baritonehands	entity))
00:54	baritonehands	(get [id]
00:54	baritonehands	(@db id))
00:54	baritonehands	(save [id updates]
00:54	baritonehands	(dosync (alter db update-in [id] merge updates)))
00:54	baritonehands	(delete [id]
00:54	baritonehands	(dosync (dissoc db id))))))
00:54	amalloy	baritonehands: long pastes to a pastebin, please, such as gist.github.com
00:56	baritonehands	justin_smith: https://gist.github.com/baritonehands/b75dc69242948308ff3d
01:02	nys-	where does the nrepl-port file go
02:55	autogen_	hey guys
03:02	alex``	hey there
03:43	devangshah	alexyakushev: i have completed the incremental build project and have it approved...
03:44	devangshah	https://github.com/celeritas9/lein-droid/tree/inc-build
03:44	devangshah	shall i create the PR?
03:45	devangshah	what would you suggest…? I want to have it merged.. :-)
03:59	jonathanj	what's the quickest dirtiest way to get the current system timestamp as a string?
03:59	jonathanj	apparently System/currentTimeMillis doesn't exist, despite javadocs telling me it does, am I missing something?
04:00	jonathanj	java.lang.RuntimeException: Unable to find static field: currentTimeMillis in class java.lang.System
04:04	ridcully_	,(System/currentTimeMillis)
04:04	clojurebot	1453367011585
04:09	TEttinger	jonathanj: were you doing:
04:09	TEttinger	,System/currentTimeMillis
04:09	clojurebot	#error {\n :cause "Unable to find static field: currentTimeMillis in class java.lang.System"\n :via\n [{:type clojure.lang.Compiler$CompilerException\n :message "java.lang.RuntimeException: Unable to find static field: currentTimeMillis in class java.lang.System, compiling:(NO_SOURCE_PATH:0:0)"\n :at [clojure.lang.Compiler analyze "Compiler.java" 6688]}\n {:type java.lang.RuntimeException\n ...
04:09	TEttinger	it is a static method
04:10	TEttinger	I can see it could have been either way though,
04:10	TEttinger	it makes sense as a field and method
04:29	Wojciech_K	Why unquote and syntax-quote are in diffrent namespaces?
04:50	neoncontrails	Wojciech_K: hehehe. They're very different in scope. If you're not sure which one you want, use quote
04:51	Wojciech_K	neoncontrails, I use syntax-quote with conjuction with unquote, the stange thing is
04:51	Wojciech_K	unquote and quote are in clojure.core
04:52	Wojciech_K	while syntax-quote is in clojure.tools.reader
04:52	Wojciech_K	syntax-quote and quote are more similar to each other than to unquote
04:58	neoncontrails	syntax-quote resolves symbols to their values in the namespace it gets called by. Between consenting adults, it's fine, but it's possible to do horrible things to other namespaces if used wrong
05:00	Wojciech_K	right, thanks
05:07	jonathanj	TEttinger: oh, you're probably right, I forgot to call it
05:07	jonathanj	how can i create a List from Clojure?
05:07	jonathanj	a List<String> to be precise
05:07	neoncontrails	,'()
05:07	clojurebot	()
05:07	jonathanj	neoncontrails: not a list, a java.util.List
05:09	jonathanj	i have a function whose signature is List<String> can i just pass ["" ...] to that?
05:09	noncom	clojure seqs implement List ? i dont' remember for sure
05:10	TEttinger	,(java.util.ArrayList. [1 2 3])
05:10	clojurebot	[1 2 3]
05:10	TEttinger	,(java.util.ArrayList. '(1 2 3))
05:10	clojurebot	[1 2 3]
05:10	noncom	looks like they do
05:11	TEttinger	not sure if vector or seq implement List. ArrayList takes a Collection IIRC, so more general
05:11	TEttinger	,(java.util.ArrayList. #{1 2 3})
05:11	clojurebot	[1 3 2]
05:11	noncom	,(instance? java.util.List [])
05:11	clojurebot	true
05:11	noncom	,(instance? java.util.List '())
05:11	clojurebot	true
05:11	TEttinger	ah good then
05:12	TEttinger	,(instance? java.util.List [1])
05:12	clojurebot	true
05:12	TEttinger	,(instance? java.util.List (range))
05:12	clojurebot	true
05:12	TEttinger	whaaaaat
05:12	noncom	cool. lists are rather widespread!
05:12	noncom	well, can't a lazy seq implement a list ? :)
05:12	TEttinger	,(class (range))
05:12	clojurebot	clojure.lang.Iterate
05:13	noncom	(.add (range) 1)
05:13	noncom	,(.add (range) 1)
05:13	clojurebot	#error {\n :cause nil\n :via\n [{:type java.lang.UnsupportedOperationException\n :message nil\n :at [clojure.lang.ASeq add "ASeq.java" 151]}]\n :trace\n [[clojure.lang.ASeq add "ASeq.java" 151]\n [sun.reflect.NativeMethodAccessorImpl invoke0 "NativeMethodAccessorImpl.java" -2]\n [sun.reflect.NativeMethodAccessorImpl invoke "NativeMethodAccessorImpl.java" 57]\n [sun.reflect.DelegatingMethodA...
05:13	noncom	hehe
05:13	jonathanj	what is a java.util.List<String> vs a java.util.List?
05:13	noncom	unsup op, what i expected
05:13	noncom	jonathanj: same
05:13	jonathanj	eh?
05:13	TEttinger	jonathanj: generics like <String> only apply in java source, they're erased in bytecode
05:13	jonathanj	what is a java.util.List<String> vs a java.util.List<Turnip> then?
05:13	noncom	same
05:13	jonathanj	oh okay
05:14	jonathanj	sorry, i don't JVM
05:14	TEttinger	it's weird in any language, the generic erasure
05:14	noncom	jonathanj: so just be aware that something may brake in runtime if the types are not friends
05:14	TEttinger	there's a reason for it, I assume, but it's still weird
05:14	noncom	the reason is always performance
05:16	TEttinger	hence why java.util.Random is at least 5x slower than a non-thread-safe linear congruential pseudo-random generator?
05:16	TEttinger	the reason there is thread safety
05:17	noncom	hmm
05:17	TEttinger	LCGs are supposed to be among the fastest RNG types, which sorta helps make up for their lousy quality
05:17	noncom	oh maybe, i don't know this matter for sure
05:18	TEttinger	I've been in RNG land recently. I had a dream last night about an RNG truncating instead of casting to int, so all the numbers it made were usually "about a billion"
05:19	noncom	:D
05:19	TEttinger	the number it returned was that text
05:19	TEttinger	good ol' dream code
05:19	noncom	omg lol :D
07:26	neoncontrails	Are tail calls acceptable if the stack depth is bounded? Say, if the function is guaranteed to terminate in 3 recursions or less
07:29	gfredericks	neoncontrails: you're wondering about the function calling itself by name instead of using recur?
07:31	neoncontrails	gfredericks: yup. Discouraged or actually risky?
07:35	neoncontrails	My recursive case-analysis works great for almost all inputs... but with an interesting exception. It fails whenever a string contains a single quotation mark , e.g. "didn't"
07:37	neoncontrails	I wonder if it might be related. The individual functions I'm passing the inputs to all work, so I wonder if it's the tail call...
08:01	oracle123	what's CLOJURE_HOME ? I am using CLOJURE_HOME ,and let set it? but in the document for socket REPL, it gives some code to run under CLOJURE_HOME, but how to set it?
08:19	ridcully_	oracle123: CLOJURE_HOME is most likely an environment variable? could you please post the link, what "document" is meant?
08:20	neoncontrails	Figured out the issue I was having earlier. Strings with single quotes (e.g. "didn't") break the SQL query, which makes sense. Is there a clever way to transliterate the single quote so I can recover the original string pretty easily when I need the literal value?
08:24	ToxicFrog	neoncontrails: use stored procedures instead, stop caring about escaping your inputs to be to SQL-safe?
08:28	neoncontrails	ToxicFrog: I think I'm on the right track then. The ` character doesn't appear to break SQL, is it safe to translate ' -> `?
08:28	ToxicFrog	neoncontrails: what? That's the complete opposite of what I suggested.
08:28	neoncontrails	I know ` is special in Clojure, but I don't think that should matter in the string
08:29	neoncontrails	ToxicFrog: sorry could you clarify what you meant then? "Stored procedures" could mean almost anything
08:29	ToxicFrog	Also, how will you handle strings that naturally include ` in them?
08:29	ToxicFrog	SQL stored procedures.
08:30	neoncontrails	Ooh I see. This is my first db app, I didn't know SQL had such things
08:30	ToxicFrog	Aka prepared statements or parameterized queries.
08:30	ToxicFrog	You write the query in SQL as a function, then call it from clojure passing in the parameters needed.
08:31	ToxicFrog	No escaping is needed, the parameters are treated as raw data even if they contain characters that would normally be special to SQL.
08:33	ToxicFrog	It requires a bit more setup up front, but it protects against SQL injection attacks, frees you from worrying about correctly escaping your stuff even if injection isn't a concern, and if you're worried about qps, it's also faster than assembling the query ex nihilo each time.
08:33	neoncontrails	Oh cool that sounds a lot more sane than what I'm currently doing. Thanks for the suggestion
08:36	ToxicFrog	Ok, it's been a while; parameterized queries and stored procedures are related but are not the same thing.
08:36	ToxicFrog	Stored procedures are written up front and stored in the DB.
08:36	ToxicFrog	Parameterized queries can be created on the fly, and might look something like this (details depend on implementation):
08:37	ToxicFrog	(sql-query-with-params "SELECT ? FROM users WHERE name == ?" field-name user-name)
08:37	ToxicFrog	field-name and user-name shouldn't be escaped and are correctly spliced into the command where the ?s appear.
08:37	ToxicFrog	neoncontrails: ^
08:38	ToxicFrog	neoncontrails: if you're using JDBC, it looks something like this: http://rosettacode.org/wiki/Parametrized_SQL_statement#Clojure
08:40	neoncontrails	ToxicFrog: awesome, I was just about to ask about jdbc. Thanks for the examples, this is really helpful
08:48	neoncontrails	ToxicFrog: Success!
08:48	neoncontrails	Thanks again, I had no idea this was a thing.
08:51	jsabeaudry	What's the status with incanter?
08:52	oracle123	about the clojure home, sorry it's not mean CLOJURE_HOME, but just clojure home, the doc says
08:52	oracle123	The simplest way to launch a Clojure repl is to use the following command line from within Clojure’s home directory:
08:52	oracle123
08:52	oracle123	java -cp clojure.jar clojure.main
08:53	oracle123	the doc is here http://clojure.org/reference/repl_and_main#_launching_a_socket_server
08:53	oracle123	but I am using lein, so where should I run the java -cp clojure.jar clojure.main?
09:04	jsabeaudry	oracle123, if you use lein you dont need to run that
09:10	oracle123	I want to start up a socket REPL in clojure 1.8, there is no doc about how to start it in lein. only show how to start it up in java.
09:11	wink	that's because 1.8 is like 2 days old
09:12	wink	I'm still trying to find out what this new socket REPL's benefits are
09:14	oracle123	I could telnet and send command to it. Maybe we could also do the same in Nrepl.
09:15	oracle123	if I start an clojure app which tightly loop doing something, if I connect to it using repl, how will it repsonse? since it's busy working in a tight loop, will it kicks off a service thread accept request and reply?
09:16	ToxicFrog	neoncontrails: you're welcome!
09:16	pbx	is there a 'lein version' equivalent that tells me the installed clojure version?
09:17	oracle123	lein version won't tell the version of clojure, and in the project.clj, we could define different version of clojure
09:18	oracle123	so it's depends on the proejct.clj, it can't give a fixed version.
09:19	hyPiRion	pbx: `clojure -e '(clojure-version)'` or `lein run -m clojure.main -e '(clojure-version)'`
09:19	wink	`lein version` would also be ambigous depends on whether it is called inside a project dir or not
09:19	wink	i.e. would you want your project clojure version, or the one lein uses?
09:25	hyPiRion	oracle123: You can change the lein repl version to 1.8.0 via https://github.com/technomancy/leiningen/blob/master/doc/PROFILES.md#replacing-default-repl-dependencies and then run something like `JVM_OPTS='-Dclojure.server.repl={:port 5555 :accept clojure.core.server/repl}' lein repl`
09:25	hyPiRion	This should start a socket which you can connect over via `telnet 127.0.0.1 5555`
09:28	neoncontrails	ToxicFrog: I think this should be possible, but just to make sure... any reason I couldn't just use the (sql/execute! ... ) method to insert the name, and use update! to populate the fields?
09:32	ToxicFrog	neoncontrails: I'm not sure what you mean by "use sql/execute! to insert the name
09:33	ToxicFrog	neoncontrails: that said, I have a suspicion that the example in (doc sql/update!) or https://github.com/clojure/java.jdbc/blob/master/src/main/clojure/clojure/java/jdbc.clj#L1042 will answer your question
09:37	oracle123	hi hyPiRion, what I am trying to do is, run a clojure app using lein run with remote repl enabled at home, then I could control its run time behaviou from outside, such as define as var using "def", and connect from another computer, modify the var value to change how the app runs.
09:37	oracle123	but using your approach, it starts a lein repl, it doesn't run my code.
09:38	oracle123	normally I am running using "lein run"
09:40	beaky	hello
09:40	neoncontrails	ToxicFrog: I'm wondering if I can compose those calls to avoid restructuring my map as an ordered seq. This works just fine: "(sql/execute! spec ["UPDATE mydb SET name = ?" "it's"]) Can I then populate it with (sql/update! spec :mydb {:name "it's"} ["fieldA = ?" 0]), or do the fields need to be declared in execute?
09:40	beaky	is clojure enterprise ready
09:41	ToxicFrog	neoncontrails: yes, and that's pretty much exactly the example given in (doc sql/update!)
09:42	ToxicFrog	In fact, that update! call of yours basically turns into: (sql/execute! spec ["UPDATE mydb SET name = ? WHERE fieldA = ?" "it's" 0])
09:42	powered	JVM is good enough for enterprises, and clojure uses JVM so I'd say yes beaky
09:57	pseudonymous	So I'm trying to retrofit my project with tests. Is there any way to mock/monkeypatch calls ? I'd like not to actively call the database. I looked into bindings but those only apply to vars (not imports?) which must be declared dynamic beforehand
09:58	tdammers	mocking databases is hilariously cumbersome
09:58	tdammers	if you want simulation tests, I suggest just running them against a real database (but not one that you care about); clear it out and fill it with whatever fixture you want before running the test, and then just point your application to it
09:58	tdammers	for unit tests, things are trickier
09:59	pseudonymous	tdammers: would not be surprised. I've given up testing many times because pretty much all my projects use databases heavily...
10:00	tdammers	I think a reasonable way to go about it is to wrap your database in a low-level-ish data access layer, and mock that
10:00	tdammers	and then use simulation tests against a test database to cover you bases
10:01	tdammers	then the only problem you might have is that your data access layer might break in ways that you cannot easily detect using your unit tests
10:01	tdammers	so the trick is to keep that layer small and simple
10:16	alex``	guys, what's the proper way of evaluating a vector passed to a macro? i'm getting the annoying "can't create ISeq from symbol" error while trying to map through the vector
10:17	justin_smith	alex``: macros can only use data that is present at compile time
10:18	justin_smith	you have to write the macro such that the data is only mapped over by the resulting code, and not accessed by the code generation
10:20	justin_smith	simple example (defmacro m [f coll] (map f coll)) won't work because coll is accessed by map at compile time, (defmacro m [f coll] (list 'map f coll)) will work, because map is not called on coll until runtime, and coll is not accessed by the macro itself
10:21	alex``	understand
10:21	alex``	but i need to map the data to generate code
10:21	justin_smith	alex``: then the data needs to be present at compile time
10:22	alex``	if i write (defmacro [& args]) it works, but saying (defmacro [args]) doesn't
10:22	jonathanj	java.lang.IllegalArgumentException: No matching method: asList
10:22	jonathanj	trying to do (java.util.Arrays/asList ...)
10:22	jonathanj	it would be useful if this error told me what it tried to match
10:23	justin_smith	,(java.util.Arrays/asList (into-array [1 2 3]))
10:23	clojurebot	[1 2 3]
10:23	justin_smith	,(type (java.util.Arrays/asList (into-array [1 2 3])))
10:23	clojurebot	java.util.Arrays$ArrayList
10:23	jonathanj	oh, is there something i should know about Java varargs functions?
10:24	justin_smith	jonathanj: varargs methods really take all the extra args as an array
10:24	jonathanj	okay, good to know
10:24	justin_smith	being picky about method / function here because they are different things in this world
10:24	jonathanj	except that didn't help me debug this stupid problem cry
10:25	jonathanj	(clojure.java.io/copy) doesn't do any encoding translation, does it? it's just straight bytes from a to b?
10:25	justin_smith	you can give an :encoding arg if you want it to convert
10:26	justin_smith	it depends on if you are going byte->byte byte->char, char->byte, char->char, iirc only the middle two need the encoding
10:26	jonathanj	i'm trying to figure out why trying to mimic <https://github.com/apache/pdfbox/blob/2.0.0-RC2/tools/src/main/java/org/apache/pdfbox/tools/ExtractImages.java#L301> is filling my file with weird junk that definitely isn't image data
10:26	jonathanj	justin_smith: it's a copy from InputStream to File
10:26	justin_smith	but it defaults to utf-8 which should usually be correct on sane systems
10:26	jonathanj	it's binary data, i definitely don't want any decoding/encoding to happen
10:26	justin_smith	jonathanj: inputstream to file is byte->byte so you are fine
10:27	justin_smith	right, you don't have chars on either side, so no worries
10:27	jonathanj	i was hoping to hear "you're a moron, you are supposed to do X" and then i'd be done debugging this
10:27	justin_smith	copy just hase the :encoding option because it can handle chars too
10:27	justin_smith	haha
10:28	justin_smith	jonathanj: I'll look out for reasons to call you a moron then
10:28	jonathanj	thanks, you're a true friend
10:28	jonathanj	dump-1: DOS executable (device driver)
10:28	jonathanj	argh
10:29	jonathanj	i've been fighting with pdfbox and java for a whole day trying to debug this nonsense
10:29	justin_smith	so the headers aren't coming out right?
10:29	justin_smith	have you tried checking cmp to see where the first differing byte is?
10:29	jonathanj	the data seems to be complete garbage
10:30	jonathanj	it seems like 99% of the file is \377
10:30	jonathanj	whatever that is, probably 0xff?
10:31	justin_smith	oh, weird
10:31	jonathanj	justin_smith: i'm trying to extract the images from a PDF, i'm just basing my code on that pdfbox code but i'm not getting anything even remotely correct
10:31	ToxicFrog	\377 is 0xFF in octal, yeah
10:31	humanbsd	Sorry for the off-topic: Anyone of you people are playing sauerbraten?
10:31	ToxicFrog	Not-entirely-joking suggestion: shell out to pdfimages(1)
10:32	justin_smith	jonathanj: so I assume you have a setup where you have a pdf generated with a known image etc.
10:33	jonathanj	justin_smith: it's such a long sad story, i'm trying to recompress the image in the PDF but i want the original image data so i can do something like estimate the JPEG quality (based on the qtables)
10:33	jonathanj	if i didn't need the original stream, i'd just use the method that gives me a BufferedImage
10:34	justin_smith	jonathanj: right, I was just thinking if I were trying to do this, I would start with a known image, and a pdf I made with that image in it, so I could look at differences between what is extracted and the original
10:34	jonathanj	i think at this point, it's probably as much work to calculate the quality than to just always resave the image and throw it away if it's bigger
10:35	jonathanj	justin_smith: that might help if the data resembled something other than garbage
10:35	justin_smith	jonathanj: well, when you have something correct to compare it too, that can only add information right?
10:35	jonathanj	justin_smith: i dunno, something weird is happening, guess i'll bash my head against it
10:35	jonathanj	justin_smith: i dunno, can it?
10:36	jonathanj	justin_smith: for some reason this data is all exactly the same size (for all different images) but `pdfimages -list` shows them as definitely not the same size
10:36	justin_smith	jonathanj: the extra 0xff makes me think that somewhere something is taking bytes and making them 16 bit characters (what the vm uses internally) and then you are outputting bytes derived from those, so it would be twice as much output, and every other byte would be 0xff
10:36	justin_smith	that's just a wild guess though
10:37	jonathanj	i thought that might be the case too but then i wouldn't expect the files to all be the same size
10:37	justin_smith	well, every other byte would be 0xff or 0x00 (sign extension...)
10:37	justin_smith	jonathanj: could be more than one thing is wrong here :)
10:38	jonathanj	justin_smith: yes, i think that may well be a possibility
10:39	justin_smith	jonathanj: how about, for debugging purposes, make an "image" that's just 0xdeadbeef over and over, and another that is just 0xfeedcafe over and over, then try extracting the two - if the output has any relation to the input at least those would be recognizable even mangled
10:39	justin_smith	well, packing them into a pdf, and then extracting them, of course
10:52	jonathanj	oh well i fixed it
10:52	justin_smith	"oh well" haha
10:53	jonathanj	apparently PDXObject.createInputStream creates an input stream containing the data for the entire XObject as it appears in the PDF
10:53	jonathanj	whereas PDFObject.getStream.createInputStream creates an input stream for only the embedded object data
10:53	justin_smith	oh, nice
10:53	justin_smith	and also weird
10:54	jonathanj	yeah, i didn't even expect that to work and the docs don't really seem to explain this
10:54	jonathanj	thanks, justin_smith
11:00	tos9	is there some atriviality to apply'ing interop-ed things
11:00	tos9	e.g. (apply (.log js/console) whatever) or (apply .someJavaThing ...
11:04	justin_smith	tos9: methods are not functions, apply is for applying function args
11:05	tos9	justin_smith: Hm, OK -- is there another thing that means that?
11:05	justin_smith	among other issues, apply takes a collection as argument, and the argument count and types will indicate different methods (unlike a function call where you might get a different arity but it is still the same function)
11:05	justin_smith	tos9: no
11:06	tos9	oh, right, multimethods... that's annoying.
11:06	beaky	hello
11:06	beaky	how do i dockerize a clojure app
11:06	justin_smith	well, multimethods are something different - but method overloading is the issue here, yes
11:06	tos9	justin_smith: So given some arguments, there's no generic way to call an interop callable thing with them?
11:07	justin_smith	beaky: make a docker image that has a jvm in it and a script that starts up your jar?
11:07	justin_smith	not that I know of
11:07	ystael	beaky: well, the simplest thing you can do is "java -jar uberjar.jar" as your CMD
11:07	ystael	there is a "clojure:1.8" image in hub
11:07	justin_smith	right, you hardly even need docker for that
11:08	tos9	justin_smith: Interesting. Thank you.
11:08	justin_smith	tos9: wait, you mentioned js/console above - I have been talking about jvm clojure
11:08	tos9	justin_smith: Yeah -- which doesn't ahve overloading, so this should be simpler there?
11:08	justin_smith	tos9: with js clojure, there are js methods that call a js function with a coll as args
11:08	tos9	justin_smith: (But I somewhat intentionally asked it generically)
11:08	justin_smith	forget how it works, but it is a thing
11:08	justin_smith	right, not generically a thing, won't work on the jvm, but js has a way to do it
11:08	tos9	Yeah I can probably use like .apply from JS land
11:09	tos9	OK, cool
11:13	beaky	ah
11:16	tos9	How to I tell lein to put ~/.lein someplace else
11:16	tos9	man lein is not a thing :/
11:17	justin_smith	tos9: lein help
11:18	tos9	justin_smith: it just prints usage info, and lein readme just prints.. the readme. I don't see anything explaining any environment variables lein respects, or config info, etc. etc.
11:21	justin_smith	tos9: config info is partially in lein help profiles, but what you want is in the sample project.clj (and yes it should also be in regular docs) https://github.com/technomancy/leiningen/blob/master/sample.project.clj#L489
11:21	tos9	Ah, awesome.
11:21	tos9	justin_smith: Thank you!
11:22	justin_smith	tos9: see also "lein help sample \| grep HOME"
11:24	justin_smith	"lein help sample" is full of amazing info (though it might be more convenient to just go to that github page)
11:25	tos9	yeah I read it a few times yesterday but was too overwhelmed at the time by all the settings to play with :)
11:25	tos9	I'll have to read it again when I shed some noobiness.
11:25	justin_smith	heh, and of course the env vars are at the bottom
11:25	justin_smith	tos9: it's a reference document, I've never read it start to finish
11:25	justin_smith	just like most man pages in fact
11:28	jonathanj	i really wish i could map (.foo) without a lambda/anonymous function
11:29	justin_smith	jonathanj: blame java for methods not being first class data, and needing some Object to carry them
11:30	justin_smith	on a bytecode level a method isn't something you can pass as an arg
11:32	justin_smith	jonathanj: the obvious rejoinder there is that clojure could wrap it for convenience reasons, but in general clj likes to stay "close to the metal" in terms of how it uses the vm, and not use implicit abstractions for interop
11:34	jonathanj	actually, now that you say that, istr some kind of function to turn a method into a clojure function, but i can't remember the name (or exactly what it does)
11:34	beaky	i love the cloud
11:34	gfredericks	#method .foo
11:34	beaky	oops wrong channel
11:34	gfredericks	,(doc memfn)
11:34	clojurebot	"([name & args]); Expands into code that creates a fn that expects to be passed an object and any args and calls the named instance method on the object passing the args. Use when you want to treat a Java method as a first-class fn. name may be type-hinted with the method receiver's type in order to avoid reflective calls."
11:34	jonathanj	that's the one
11:34	justin_smith	memfn is depricated though
11:34	justin_smith	it's better to just use #(.foo %)
11:35	gfredericks	because of default-reflection?
11:35	gfredericks	well that's no different from #(.foo %) I guess
11:35	gfredericks	I'd never heard that it was deprecated
11:35	justin_smith	somehow #(.foo %) can be optimized where memfn isn't, I forget the details it's been ages since I learned about this...
11:36	gfredericks	surely you could implement memfn with #()
11:36	justin_smith	gfredericks: now I'm wondering if it was "deprecated" or just "there's no case where using it is better than just using a lambda"
11:37	gfredericks	that sounds a lot more likely
11:37	gfredericks	it makes you feel clever
12:51	cap10morgan_	Is clojurebot's source code on GitHub somewhere?
12:51	justin_smith	yes
12:51	justin_smith	https://github.com/hiredman/clojurebot
12:51	cap10morgan	justin_smith: cool, was just going to ask if that was the one. thanks!
14:14	elvis4526	Is there an alternative to this: (alter-var-root #'get-all-users (fn [of] (fn [request] "poo")))
14:14	elvis4526
14:14	elvis4526	Im the repl and i want to redefine a var assigned to a function inside a namespace
14:15	elvis4526	(or perhaps its the function that is assigned to the var)
14:16	justin_smith	elvis4526: (intern 'some-ns 'some-symbol value)
14:17	justin_smith	and you can also do (in-ns 'random-ns) (def ...) (in-ns 'other-ns)
14:18	justin_smith	,(intern 'some-ns 'some-var 42)
14:18	clojurebot	#error {\n :cause "No namespace: some-ns found"\n :via\n [{:type java.lang.Exception\n :message "No namespace: some-ns found"\n :at [clojure.core$the_ns invokeStatic "core.clj" 4032]}]\n :trace\n [[clojure.core$the_ns invokeStatic "core.clj" 4032]\n [clojure.core$intern invokeStatic "core.clj" 6071]\n [clojure.core$intern invoke "core.clj" 6071]\n [sandbox$eval25 invokeStatic "NO_SOURCE_FIL...
14:18	justin_smith	oops!
14:18	justin_smith	,(create-ns 'some-ns)
14:18	clojurebot	#object[clojure.lang.Namespace 0x1b74fd63 "some-ns"]
14:18	justin_smith	,(intern 'some-ns 'some-var 42)
14:18	clojurebot	#'some-ns/some-var
14:19	justin_smith	,some-ns/some-var
14:19	clojurebot	42
14:34	elvis4526	Ha I didn't know changing it with def was allowed when you were in the same namespace
14:35	elvis4526	its working perfectly thanks
14:35	justin_smith	cool
14:35	justin_smith	elvis4526: yeah, that's why the repl is so useful, being able to redefine in a running system just by running the new code
14:54	justin_smith	playing with this new socket server thing in 1.8, it's pretty cool, especially being able to run a repl just based on a command line arg with no code added to the codebase
15:00	wht_rbt	probably a newb question here -- does clojure have a way to prompt a user for a password on the console, so that the user's input does not echo?
15:03	Shayanjm	wht_rbt: not sure about Clojure specifically, but Java has java.io.Console.readPassword
15:03	domokato	line-seq makes a lazy sequence - does that mean it reads from a file when the elements are gotten from the resulting seq?
15:04	amalloy	domokato: yes
15:04	domokato	amalloy: th
15:04	domokato	amalloy: thx
15:08	wht_rbt	Chayanjm: thnx - I went down that rabbit hole, but ended up getting strange results
15:08	wht_rbt	similar to this: https://groups.google.com/forum/#!topic/clojure/hlv2m00hhgU
15:08	wht_rbt	System.console was coming back null for me
15:24	tos9	I have 4 channels which contain 1 value each. I want to join the 4 values -- what's the easiest way to do that?
15:24	tos9	I see async/merge for one way?
15:24	tos9	join the 4 values as 1 str
15:33	optikalmouse	does clojure have the same Environment stuff as Common Lisp? like trace/untrace, dribble, etc.?
15:33	elvis4526	tos9: i'd use async/merge yes
15:33	optikalmouse	or actually man I would love to have APROPOS
15:34	jonathanj	,(doc apropos)
15:34	clojurebot	"([str-or-pattern]); Given a regular expression or stringable thing, return a seq of all public definitions in all currently-loaded namespaces that match the str-or-pattern."
15:34	tos9	elvis4526: I must be doing that wrong I think, because (go (let [strs (<! (async/map str (async/merge comments)))] (println strs))) gives me Error: [object Object] is not ISeqable
15:35	elvis4526	tos9: is comments a list of channels ?
15:36	tos9	elvis4526: yes (although let me print it to be sure)
15:37	tos9	it's: (#object[cljs.core.async.impl.channels.ManyToManyChannel] #object[cljs.core.async.impl.channels.ManyToManyChannel])
15:37	jonathanj	merge returns one channel
15:37	jonathanj	map expects a seq
15:37	tos9	a ha
15:37	elvis4526	thats what i was about to say
15:37	elvis4526	Usage: (map f chs)
15:37	elvis4526
15:39	tos9	does that mean that I want (reduce str "" (async/merge comments)) then? Or does it mean I'm highly confused (Which I probably am).
15:39	jonathanj	so comments is a bunch of channels that each return one comment? more than one comment?
15:39	tos9	jonathanj: they're a bunch of channels, each has 1 comment in it, yeah.
15:39	jonathanj	tos9: merge returns a channel, clojure.core/reduce doesn't know how to reduce a channel, does it?
15:40	tos9	jonathanj: no, but along with like a <!
15:40	tos9	oh hm no
15:40	tos9	yeah that doesn't work.
15:40	jonathanj	so what are you trying to do?
15:40	tos9	jonathanj: I have those 4 channels which contain 1 comment each which are strs. I want 1 str which is the concat of those 4 strs.
15:40	tos9	(I'll want to interleave some other HTML, but first I want to see ^)
15:41	jonathanj	i think a transducer might make building that processing chain easier
15:41	tos9	Yeah so it seeeems likely that that's true, and also it seems like cljs-http can take a channel rather than returning one, in which case I could probably get it to put my responses all on the same channel
15:41	beaky	helllo
15:41	beaky	is om production ready
15:42	elvis4526	tos9: You could loop over the output channel with go-loop, collect each string and concat them for each iterations
15:42	tos9	But I'm trying not to change my approach in a way that complicates it, I'm only like 3 hours into clojure programming :P
15:42	jonathanj	tos9: sorry i barely know anything about core.async so i can't really suggest a concrete solution
15:42	domokato	map-indexed should perform better than dotimes + nth, right?
15:42	tos9	elvis4526: The merged one? Cool that sounds like a thing I might be able to do. Will give it a shot.
15:42	tos9	jonathanj: Have you seen the evil thing I'm working on?
15:42	elvis4526	tos9: yes the merged one
15:43	jonathanj	tos9: no, sorry i just started reading IRC
15:43	tos9	jonathanj: Well you will soon, it's complete techcrap :)
15:54	mistnim	hi, what is clojure commonly used for? web development? anything else?
15:55	tos9	what's wrong with my syntax here: https://github.com/Julian/sphinxcontrib-githubcomments/blob/master/src-cljs/githubcomments/core.cljs#L10-L14
15:55	tos9	clojure is telling me I'm not allowed to recur there
15:56	optikalmouse	jonathanj: thx!
15:58	jonathanj	tos9: i don't think you (recur) in a (go-loop)
15:58	hiredman	of course you can
15:59	tos9	jonathanj: I'm copying the example at https://clojuredocs.org/clojure.core.async/go-loop
15:59	tos9	or at least I think I am
15:59	jonathanj	oh you do, sorry, the docs are just really sparse
16:00	hiredman	tos9: replace go-loop with (go (loop [ ...] ...)) and then ask yourself what is wrong
16:00	tos9	hiredman: I did, and then got "wrong number of arguments to recur
16:00	hiredman	tos9: do you know how loop/recur works?
16:00	tos9	hiredman: I do not!
16:00	tos9	I'm reading the docs on loop now
16:00	hiredman	tos9: good
16:01	tos9	Oh I see.
16:01	tos9	I need to pass the 2 new values.
16:06	elvis4526	tos9: there is probably a better way to do it, but this is what I had in mind https://gist.github.com/j-allard/1efb23c2e13af35ed490
16:09	justin_smith	jonathanj: regarding "map expects a seq" - the two argument version of map doesn't need a seq, and can be applied as a transducer on a channel
16:15	justin_smith	,(sequence (map inc) (range 10))
16:15	clojurebot	(1 2 3 4 5 ...)
16:15	justin_smith	and can also use a seq
16:16	jonathanj	justin_smith: i meant (clojure.core.async/map) which was the function in question, i was just lazy
16:16	justin_smith	jonathanj: clojure.core.async/map is depricated
16:16	justin_smith	it's just map now
16:16	jonathanj	mmm, the docs don't say it's deprecated
16:16	jonathanj	so how do you apply a transducer to a channel?
16:17	justin_smith	jonathanj: sorry, it's map> and map< that are depricated, map is still legit
16:18	justin_smith	jonathanj: you can provide a transducer as an optional arg to a channel
16:18	jonathanj	hmm, that seems kind of inconvenient, like if you merge, how do you apply a transducer to a channel you didn't create?
16:20	justin_smith	jonathanj: by piping onto a channel you did create, which has the transforms you want
16:20	justin_smith	or using pipeline
16:21	justin_smith	this is how we replace all the "Depricated - this function will be removed. Use transducer instead" functions
16:27	amalloy	justin_smith: replace them with "Deprecated"?
16:46	rcassidy	been using vim&fireplace with clojure and it's been awesome, but i'm missing one feature
16:49	rcassidy	jumping to definition of a symbol is easy -- any way to find usage of a symbol across files? something like ctags does in vim for :ts ?
16:55	justin_smith	rcassidy: sad but true, I usually just reply on grep -Rn ...
16:56	justin_smith	*rely
16:56	justin_smith	emacs has a mode where it lists the hits and there's a keyboard shortcut to visit the next hit etc.
16:56	justin_smith	I'm sure vim has some sort of grep / silver searcher plugin
16:57	rcassidy	justin_smith: thanks, that's what I'm doing too re: grep
16:57	rcassidy	ctags was nice for c++ in vim, can easily find all occurrences of a symbol and hop around based on the tag... sad there's not a similar thing that fits into fireplace
17:01	justin_smith	rcassidy: I've never seen tags for lisps like for algol family languages, I don't know if that's coincidence or some property of lispy languages that makes tags less useful or what
17:02	rcassidy	i saw some ctags syntax regexes to add support for tags, but doing c-style tags on top of fireplace just for one feature feels like overkill
17:02	rcassidy	and I don't feel like setting up my tagfile right now at work :p
17:02	rcassidy	s/support for tags/support for clojure tags/
17:04	justin_smith	rcassidy: oh look, you can generate a tags file for clojure with etags http://stackoverflow.com/questions/1481842/clojure-emacs-etags
17:05	justin_smith	rcassidy: more relevant https://gist.github.com/vladh/1e1e7bc5eb274235e0b9
17:05	rcassidy	found those :)
17:05	rcassidy	like I said, I could just straight use ctags, but that's a lot of cruft just to avoid grepping
17:06	rcassidy	maybe i'll give in eventually
17:06	justin_smith	true that
17:06	justin_smith	eventually CPU / disk speed improvement beats the old clever caching maybe
17:13	tos9	elvis4526: Sorry - I jumped into a meeting -- thanks I think that's really helpful
17:14	tos9	I still can't get go-loop to work, and probably I don't understand scoping 100% yet
17:14	tos9	But I've just tried https://github.com/Julian/sphinxcontrib-githubcomments/blob/master/src-cljs/githubcomments/core.cljs#L10-L14 which appears to do something, although it also pegs a CPU, so maybe my channels aren't closing after the value pops out
17:15	justin_smith	tos9: why do you have an infinite loop inside your set! call?
17:16	justin_smith	the loop never returns, so set! never gets called
17:16	tos9	a ha -- OK, so I guess I need to figure out how <! tells me that there's nothing left to read then?
17:16	justin_smith	it will return nil if the channel is closed
17:17	tos9	Ah cool! OK, /me tries.
17:17	justin_smith	then you can conditionally recur only if hte channel is open
17:17	justin_smith	and then close the channel on the writing end
17:19	tos9	I wish I knew the paredit things already, it'd make editing not be completely tedious :P
17:22	tos9	! Amazing :) it works.
17:22	justin_smith	nice
17:26	tos9	justin_smith: http://platform-guild.readthedocs.org/en/latest/code-review.html
17:27	tos9	the result of my evil handiwork (so far, still needs lots of work)
17:27	tos9	but that bottom text box (the gray one) is what I just spent 2 evil days on -- bringing github comments onto a source doc at the client side, so thanks, appreciated
17:27	justin_smith	very cool
17:27	tos9	Now I just need to work on styling and some other nonsense.
17:28	tos9	And also on figuring out why apparently these AJAX requests aren't automatically cached by browsers :/
17:29	tos9	Are there any general tips for making https://github.com/Julian/sphinxcontrib-githubcomments/blob/master/src-cljs/githubcomments/core.cljs look more idiomatic overall?
17:32	justin_smith	tos9: why are you calling apply on line 31 instead of just calling the function?
17:33	tos9	because it started off as dorun and as a thing with side effects (to print), fixing now :)
18:30	justin_smith	tos9: I think your loop could be (reduce str "" comments)
18:30	justin_smith	async/reduce that is
18:34	justin_smith	tos9: https://gist.github.com/noisesmith/4fb0b6fec934128d89e1
18:35	justin_smith	totally works as a async/reduce call, which is cool
18:35	justin_smith	reduce doesn't even need to be in a go block, which makes sense
18:57	nuttynutnut	hi
18:59	nuttynutnut	is there a simple way to find the longest end subsequence of a number? like for 32541 it would be 541
18:59	nuttynutnut	for 1428531 it would be 8531, for 61256 it would just be 6
18:59	nuttynutnut	i came up with one solution but i was wondering if there was a better way.. one sec lemme code it up
19:06	tos9	justin_smith: Ah awesome! That does work -- I tried it before but I didn't realize async/reduce returns a channel
19:08	tos9	justin_smith: it doesn't look like cljs.core.async has <!! so I think I do need to keep the go blcok though?
19:09	justin_smith	tos9: oh, I only used <!! and >!! so that I could use the repl interactively
19:09	justin_smith	tos9: in the real code do all the puts and takes in go blocks
19:10	tos9	justin_smith: Ah, OK, good.
19:13	nuttynutnut	ok back
19:13	nuttynutnut	that took longer than expected
19:13	nuttynutnut	so i came up with something like this but there must be a more elegant way, right? (distinct (flatten (take-while (fn [[l r]] (> (int r) (int l))) (partition 2 1 (reverse (str 32541))))))
19:15	justin_smith	I think you'd want something like (map first ...) or (map second ...) rather than (distinct (flatten ...))
19:15	nuttynutnut	that doesnt work
19:16	nuttynutnut	it only gives 14 and not 145
19:16	nuttynutnut	oh and yeah it needs to be 541 so then i need to reverse
19:17	nuttynutnut	so it'd be .. (reverse (distinct (flatten (take-while (fn [[l r]] (> (int r) (int l))) (partition 2 1 (reverse (str 32541)))))))
19:17	nuttynutnut	gross
19:17	justin_smith	and that's still giving chars and not numbers
19:18	nuttynutnut	yeah
19:19	justin_smith	,(defn rev-digits [n] (->> n (iterate #(quot % 10)) (take-while (complement zero?)) (map #(rem % 10))))
19:19	clojurebot	#'sandbox/rev-digits
19:19	justin_smith	,(let [digits (rev-digits 52741)] (reduce (fn [digs d] (if (< d (first digs)) digs (conj digs d))) (take 1 digits) (rest digits)))
19:19	clojurebot	(7 4 1)
19:20	justin_smith	oops!
19:20	justin_smith	,(let [digits (rev-digits 52741)] (reduce (fn [digs d] (if (<= d (first digs)) (reduced digs) (conj digs d))) (take 1 digits) (rest digits)))
19:20	clojurebot	(7 4 1)
19:21	justin_smith	bonus: real math instead of string hacks
19:22	justin_smith	nuttynutnut: also, that version finds the sequence starting at the end, which is guaranteed to do the minimum amount of checks
19:23	nuttynutnut	yeah pretty cool
19:23	nuttynutnut	clojure is missing a function
19:23	nuttynutnut	there should be something in the core that lets you compare two elements at a time
19:23	nuttynutnut	there's so many times in a lot of these 4clojure problems that i have to compare the current item and the next item
19:24	nuttynutnut	have to end up doing some weird partition hack and then extracting the result from the vector later
19:24	justin_smith	or a reduce
19:24	nuttynutnut	yeah but that's ugly too
19:24	ystael	nuttynutnut: reduce is love, reduce is life
19:24	nuttynutnut	anything can be done with reduce
19:24	nuttynutnut	reduce is just like doing a for loop in imperative
19:24	justin_smith	(inc ystael)
19:24	nuttynutnut	higher abstractions are better
19:25	justin_smith	nuttynutnut: it's like a list comprehension that iterates over elements of one sequence and can optionally exit early
19:25	justin_smith	it's no for loop
19:25	justin_smith	or even clojure's for for that matter
19:26	nuttynutnut	it's just a loop with an accumulator
19:26	justin_smith	no it's not, because it is guaranteed to only run as many cycles as the number of elements in your input
19:26	justin_smith	it's not an arbitrary loop
19:26	justin_smith	we have "loop" for that
19:27	ystael	nuttynutnut: possibly not coincidentally, a computer is a loop (device for performing repetitive computation) with an accumulator (memory)
19:27	nuttynutnut	like.. something like this would be cool (taking-peak #(< %1 %2) [1 2 5 4 3])
19:27	nuttynutnut	actually even better
19:27	nuttynutnut	an overload for take, filter, etc. that take 2 parameters instead of one
19:27	justin_smith	nuttynutnut: (reduce max 1 2 3 4 5)
19:27	nuttynutnut	so you could optionally look at the next item
19:28	nuttynutnut	?
19:28	nuttynutnut	that doesnt run
19:28	justin_smith	nuttynutnut: (reduce max [1 2 3 4 5])
19:28	justin_smith	which is the same as apply max, of course
19:28	justin_smith	unless that's not what you mean by "taking-peak"
19:28	nuttynutnut	taking-peak is just like take-while
19:29	justin_smith	oh, yeah mean peek
19:29	nuttynutnut	is it possible to add an overload to functions like take-while so their function takes 2 arguments instead of one?
19:29	nuttynutnut	so you could optionally use the take-while that just looks at the current value
19:29	nuttynutnut	or the one that looks at both
19:30	nuttynutnut	i think that'd be pretty cool
19:30	nuttynutnut	so often with these functions i need to look at the next or previous items in the sequence as well
19:30	nuttynutnut	and you can't so you have to use some hacky reduce
19:30	nuttynutnut	could be added to filter, reduce, map, etc.
19:30	TEttinger	or defined in a lib
19:30	ystael	nuttynutnut: it would be more coherent to mimic the behavior of map, which treats all its arguments after the function as successive arguments to the function
19:31	TEttinger	,(map + [1 2 3] [20 40 60])
19:31	clojurebot	(21 42 63)
19:31	nuttynutnut	yeah that could be a problem
19:31	TEttinger	one way you could do it is with...
19:32	TEttinger	,(defn map-ahead [f coll] (map f coll (rest coll)))
19:32	clojurebot	#'sandbox/map-ahead
19:32	amalloy	nuttynutnut: don't do it with special overloads to all sequence functions, just use partitino
19:32	TEttinger	where the second argument to f is the next element in the collection, and the last element isn't used
19:32	amalloy	,(partition 2 1 (range 5))
19:32	nuttynutnut	it's messy though
19:33	clojurebot	((0 1) (1 2) (2 3) (3 4))
19:33	nuttynutnut	because you have to extract the values later
19:34	justin_smith	sounds like a job for a monad
19:34	nuttynutnut	i showed the code above that was required to get 541 from 32541
19:34	nuttynutnut	(reverse (distinct (flatten (take-while (fn [[l r]] (> (int r) (int l))) (partition 2 1 (reverse (str 32541)))))))
19:34	nuttynutnut	with this it could instead be something like..
19:34	TEttinger	,(defn map-ahead [f coll] (map f coll (rest (cycle coll))))
19:34	clojurebot	#'sandbox/map-ahead
19:34	justin_smith	nuttynutnut: flatten is 100x as hacky as the worst reduce
19:34	nuttynutnut	(take-while #(< %1 %2) (reverse (str 32541)))
19:34	nuttynutnut	or something like that
19:35	nuttynutnut	well yeah flatten is bad too
19:35	nuttynutnut	im saying there's no good solution
19:35	nuttynutnut	that's concise
19:35	amalloy	justin_smith: probably a comonad actually, right? like that's what zippers are for
19:35	nuttynutnut	or if there is i'd like to be made aware of it
19:35	justin_smith	amalloy: that's over my head still, but sure, sounds legit
19:35	amalloy	haha
19:36	TEttinger	what does that function even do, nuttynutnut? finds an increasing section of a sequence starting from the back?
19:36	nuttynutnut	yeah
19:36	nuttynutnut	the reason im trying to make it:
19:36	amalloy	well mine too, mostly. but as i understand zippers, a zipper on a list is a "pointer" to one specific element in the overall list, with a (get) function to read the current element, and functions (left) and (right) to give you a new zipper with a new focus
19:36	justin_smith	TEttinger: digits of a number actually
19:37	nuttynutnut	http://stackoverflow.com/questions/352203/generating-permutations-lazily control+f for "Find the longest "tail" that is ordered in decreasing order. (The "541" part.)"
19:37	justin_smith	amalloy: oh yeah, nuttynutnut could totally be using a zipper
19:37	nuttynutnut	trying to code that first step concisely
19:37	nuttynutnut	zippers huh?
19:37	nuttynutnut	ive heard of them but no idea what they do
19:37	nuttynutnut	is that a good solution to this?
19:37	justin_smith	nuttynutnut: yeah, check the api - from a given position you can look at the values to the left and right etc.
19:37	nuttynutnut	o
19:37	nuttynutnut	thats perfect
19:38	justin_smith	or even up and down in a tree
19:38	nuttynutnut	ok ill look in to those
19:39	TEttinger	,(reductions #(or (< %1 %2) (reduced %1)) (reverse "32541"))
19:39	clojurebot	#<ClassCastException java.lang.ClassCastException: java.lang.Character cannot be cast to java.lang.Number>
19:40	justin_smith	I was just playing with the new clojure 1.8 socket repl, accidentally printed an infinite lazy seq, and Control-C just locked up the terminal until I shut down the socket server
19:40	TEttinger	,(reductions #(or (< %1 %2) (reduced %1)) (map int (reverse "32541")))
19:40	clojurebot	#<ClassCastException java.lang.ClassCastException: java.lang.Boolean cannot be cast to java.lang.Number>
19:40	TEttinger	gah
19:40	TEttinger	,(reductions #(if (< %1 %2) %1 (reduced %1)) (map int (reverse "32541")))
19:40	clojurebot	(49 49 49 49 49)
19:40	TEttinger	right.
19:40	irctc	Is there a function like map, but where I can discard some elements? A kind of combined remove+map where I would remove elements I don't need, and transform the ones I do at the same time?
19:40	nuttynutnut	yeah that was messing with me earlier too
19:40	nuttynutnut	lol
19:40	nuttynutnut	filter?
19:40	clojurebot	filter is not map
19:40	justin_smith	irctc: mapcat
19:41	justin_smith	irctc: or keep
19:41	justin_smith	(doc keep)
19:41	irctc	hum, I'll have a look at all of these
19:41	clojurebot	"([f] [f coll]); Returns a lazy sequence of the non-nil results of (f item). Note, this means false return values will be included. f must be free of side-effects. Returns a transducer when no collection is provided."
19:41	justin_smith	keep if you never want a nil element
19:42	justin_smith	mapcat is more general and allows nil elements and also removing elements
19:42	justin_smith	(but it's a little clumsier)
19:42	irctc	Keep is exactly what I want thanks
19:43	justin_smith	,(mapcat #(cond (even? %) [%] (> 10 %) [nil] :true nil) [2 3 4 12 13 14])
19:43	clojurebot	(2 nil 4 12 14)
19:44	justin_smith	keep couldn't do that because it eats all nils (but clearly keep works for your case)
19:44	didibus	Ya, I won't have nils
19:44	didibus	But it's good to know mapcat is there if I ever need it
19:45	justin_smith	usually people only think of mapcat as combining multiple results per item, but really it's the options for "0 or more results per item"
19:48	didibus	Ya, I'm still slowly learning about all the core functions, there's just so many awesome jewel
19:52	TEttinger	,(reduce #(if (< (or (first %1) -1) %2) (apply vector %2 %1) (reduced %1)) [] (map #(Character/digit % 10) (reverse "32541")))
19:52	TEttinger	seems too long
19:52	clojurebot	[5 4 1]
19:54	nuttynutnut	yeah still pretty long
20:02	amalloy	mapcat is a primitive operation powerful enough to implement map, filter, keep, and a whole bunch of other stuff in terms of
20:02	justin_smith	yupyup
20:12	neoncontrails	Speaking of core functions. I'm working on something that requires taking a lot of set intersections, lots of set membership queries. I need persistent collections, rather than the lazy ones I keep creating with map
20:13	justin_smith	,(into #{} (map #(* % %)) [1 2 3 4]) ; like this?
20:13	clojurebot	#{1 4 9 16}
20:13	neoncontrails	Is there an eager alternative? A better core function to use when you generally need to build the structure in memory?
20:14	justin_smith	neoncontrails: that's what the map transducer used with into is for, yes
20:14	justin_smith	the above builds a set with the help of the transducing function generated by the single arity version of map
20:14	justin_smith	*single arg arity of map
20:15	neoncontrails	justin_smith: interesting. I didn't know into had that property, that's useful
20:16	justin_smith	neoncontrails: yeah, the idea with the whole transducers thing is not needing to generate a lazy seq if you know you already need a different data structure, and into is one of the most straightforward ways to use a transducer
20:18	neoncontrails	Maybe today is the day I'll learn what transducers are. I read up on them a few months ago, and there was lots of head whooshing
20:27	justin_smith	neoncontrails: it should be straightforward to parse out what into does with a single transducer arg (like (map f) or (filter f)) with trial and error
20:28	justin_smith	after that comes composing transducers, etc.
20:37	neoncontrails	It is with consistent practice, yeah. There's an interesting variety of types in Clojure that makes the patterns a little harder to see than in Scheme
20:38	neoncontrails	But it's a nice variety. I dig it
22:36	rhg135	any idea why a put! to a manifold stream would immediatly return false if it's not closed
23:26	bja	any idea why the .setBounds in this snippet seems to be underestimating the height of my images consistently? https://gist.github.com/555c96a26dab2483c671
23:26	bja	this is probably just a swing 101 question, not precisely a clojure question, although it is in clojure
23:38	John[Lisbeth]	where is the bin for ghci located in ubuntu?
23:39	John[Lisbeth]	oops
23:51	rhg135	https://www.refheap.com/113945 this is really perplexing, it was working before and I don't recall changing the relevant code