2014-07-26
| 00:19 | razum2um | why there is a clojure.lang.PersistentList$EmptyList and no clojure.lang.PersistentArrayMap$EmptyMap ? |
| 00:20 | bbloom | razum2um: both are / would-be implementation details |
| 00:20 | razum2um | why do PersistentArrayMap even exist? in source is written that "only appropriate for _very_small_ maps" |
| 00:20 | bbloom | ,(class {}) |
| 00:20 | clojurebot | clojure.lang.PersistentArrayMap |
| 00:20 | benedikt | http://lpaste.net/4733493919461933056 # this wont work, but i swear it worked just a few minutes ago |
| 00:20 | bbloom | ,(class {:x 1 :y 2 :z 3}) |
| 00:20 | clojurebot | clojure.lang.PersistentArrayMap |
| 00:20 | bbloom | ,(class {:x 1 :y 2 :z 3 :a 4 :b 5 :c 6 :d 7 :e 8}) |
| 00:20 | clojurebot | clojure.lang.PersistentArrayMap |
| 00:21 | razum2um | bbloom: yep, still a small map? |
| 00:21 | bbloom | ,(class {:x 1 :y 2 :z 3 :a 4 :b 5 :c 6 :d 7 :e 8 :f 9 :g 10 :h 11 :asdf 123 :xxx 535835}) |
| 00:21 | clojurebot | clojure.lang.PersistentHashMap |
| 00:21 | bbloom | razum2um: it's faster to do a linear scan of a small array than to bother hashing elements |
| 00:21 | bbloom | once you get past a certain size, that stops being appropriate |
| 00:21 | razum2um | bbloom: I think it's strange to have different (but similar) classes based on size |
| 00:22 | bbloom | razum2um: it's not strange at all, it's half the reason for interfaces in the first place |
| 00:22 | bbloom | (doc array-map) ; probably a design error that this exists |
| 00:22 | clojurebot | "([] [& keyvals]); Constructs an array-map. If any keys are equal, they are handled as if by repeated uses of assoc." |
| 00:22 | razum2um | bbloom: I see they implement the same |
| 00:22 | bbloom | just use hash-map |
| 00:22 | bbloom | or the {...} notation |
| 00:23 | bbloom | razum2um: it's about performance |
| 00:23 | bbloom | but it's an implementation detail |
| 00:24 | razum2um | ok, but i think PersistentList$EmptyList is also for that reason, why not similar like PersistentHashMap$ArrayMap |
| 00:24 | bbloom | razum2um: no, it's an implementation detail |
| 00:24 | bbloom | just write () |
| 00:24 | razum2um | bbloom: ok then :S |
| 00:24 | bbloom | ,(class ()) |
| 00:24 | clojurebot | clojure.lang.PersistentList$EmptyList |
| 00:30 | razum2um | bbloom: btw i see int HASHTABLE_THRESHOLD = 16 in source. it there any explanatin for that choice? |
| 00:30 | bbloom | razum2um: empirical testing |
| 00:31 | bbloom | clojurescript sets that value lower: 8 |
| 00:31 | blur3d | Hey guys, I’m trying to update an atom value, but it’s a nested hashmap, with a hashmap key, uses destructuring . It’s not as complex as it sounds, but I am trying to avoid having to use assoc-in and update-id together |
| 00:31 | bbloom | again, from measuring |
| 00:31 | blur3d | http://pastebin.com/V76nE8Nu |
| 00:31 | blur3d | basically, is there a better way to write (swap! app-state assoc-in [:sensors] (update-in (:sensors @app-state) [{:kind :temperature :label-id 1}] conj [99.9 1])) |
| 00:32 | bbloom | blur3d: so you're right to be worried, but not about the assoc-in/update-in combo... should be worried when you see a @ and a swap! like that together |
| 00:32 | bbloom | the point of a swap is that it's atomic, so when you read with @ you may get two inconsistent values (in a concurrent situtation) |
| 00:32 | blur3d | haha, yeah.. that was also concerning |
| 00:33 | blur3d | if I can somehow use :sensors in the update-in destructuring, then it should be ok |
| 00:33 | bbloom | just use fn |
| 00:34 | blur3d | but I get an error trying to mix [:sensors {:kind :temperature :label-id 1}] |
| 00:34 | bbloom | (fn [{:keys [sensors]} ....) |
| 00:34 | bbloom | (fn [{:keys [sensors]}] ....) ; imean |
| 00:34 | bbloom | oh, huh? what error are you seeing? |
| 00:35 | blur3d | im not great with destructuring yet, so how would that fit in? |
| 00:35 | bbloom | (swap! app-state update-in [:sensors {:kind :temperature :label-id 1}] conj [99.9 1])) |
| 00:35 | bbloom | that doesn't work? |
| 00:35 | blur3d | with something like this (swap! app-state update-in (:sensors @app-state) [:sensors {:kind :temperature :label-id 1}] conj [99.9 1]) |
| 00:36 | blur3d | UnsupportedOperationException nth not supported on this type: PersistentHashMap clojure.lang.RT.nthFrom (RT.java:857) |
| 00:36 | blur3d | but obviosuly still as @ as well |
| 00:36 | bbloom | blur3d: re-read the doc strings for swap! and update-in |
| 00:36 | bbloom | you're giving it bad arguments |
| 00:36 | bbloom | (doc swap!) |
| 00:36 | clojurebot | "([atom f] [atom f x] [atom f x y] [atom f x y & ...]); Atomically swaps the value of atom to be: (apply f current-value-of-atom args). Note that f may be called multiple times, and thus should be free of side effects. Returns the value that was swapped in." |
| 00:36 | bbloom | (doc update-in) |
| 00:36 | clojurebot | "([m [k & ks] f & args]); 'Updates' a value in a nested associative structure, where ks is a sequence of keys and f is a function that will take the old value and any supplied args and return the new value, and returns a new nested structure. If any levels do not exist, hash-maps will be created." |
| 00:38 | bbloom | swap! and update-in play nice together usually, but two things here 1) when you're learning, get it right without state first, then add state as you need it |
| 00:38 | bbloom | and 2) you generally want to keep your "thinking" and "acting" separate anyway |
| 00:38 | blur3d | replacing an atom value is fairly obvious, but I get tricked up over the updating part |
| 00:38 | blur3d | ok |
| 00:38 | bbloom | (def an-app-state {:sensors ...}) ; no atom |
| 00:38 | bbloom | and try update-in on that |
| 00:39 | bbloom | let me know when you have that working |
| 00:39 | blur3d | I did play around with it a bit, but the hashmap has changed also |
| 00:39 | blur3d | ok |
| 00:47 | blur3d | bbloom: I think I got it all working for the simple case with an atom… thanks for your help |
| 00:47 | blur3d | (def app2 (atom {:sensors {{:kind :temperature :label-id 1} [[21, 0]]}})) |
| 00:47 | blur3d | (swap! app2 update-in [:sensors {:kind :temperature :label-id 1}] conj [1 1]) |
| 00:47 | bbloom | blur3d: yup |
| 00:47 | blur3d | :) |
| 00:47 | bbloom | generally, it's a very good idea to have very few swap! calls |
| 00:48 | bbloom | or at least if you have a whole bunch of swap! calls, they should use pure functions defined elsewhere |
| 00:48 | bbloom | this way you can test the pure functions! |
| 00:48 | blur3d | this is for a clojurescript app, that will be sent data via websockets… so its for the app-state |
| 00:48 | blur3d | ok, sounds good |
| 02:39 | razum2um | clojure is cool at metadata, which can be bound to functions too, but is there any way to get function's (anonymous) metadata inside the same function. e.g. own metadata? |
| 02:56 | Bronsa | razum2um: ##(^:foo (fn x [] (meta x))) |
| 02:56 | lazybot | ⇒ nil |
| 02:56 | Bronsa | wut |
| 02:56 | Bronsa | ,(^:foo (fn x [] (meta x))) |
| 02:56 | clojurebot | {:foo true} |
| 02:56 | Bronsa | oh well. |
| 02:58 | Bronsa | hiredman: what's with the 10 locals limit for hoisting? |
| 03:04 | allenj12__ | hey does anyone here have experience using overtone? is there a recommended editor for it? |
| 03:11 | alexyakushev | allenj12__: I haven't used Overtone, but I suspect https://github.com/overtone/emacs-live is what you are looking for |
| 06:22 | Ro_ | I have a general question, do not know where to ask.. How triplets relate to graph? |
| 06:44 | alexyakushev | So I am trying to AOT-compile Clojure sources using a slim JAR and I get this: https://www.refheap.com/88608 |
| 06:46 | alexyakushev | This happens when the compiler gets to gvec.clj:122, where print-method is defined for ::VecSeq |
| 06:49 | boxed | Ro_: triplets? graph? |
| 06:49 | boxed | Ro_: you might need to give some more context |
| 08:10 | Ro_ | no context ;) |
| 08:11 | Ro_ | I was searching for an answer how does triples relate to graph, how can they be converted from one to another |
| 08:12 | Ro_ | is it possible to create hypergraph with tripplets |
| 08:16 | Ro_ | and etc. |
| 08:44 | katratxo | Ro_: e.g. http://www.snee.com/bobdc.blog/2014/01/storing-and-querying-rdf-in-ne.html |
| 09:15 | formaggio | hi 'veryone |
| 09:53 | john2x | question about Luminus. what is this `servlet-context` in the generated templates? they seem to be blank when running the dev server. Are these meant for production? |
| 10:12 | deathknight | What is a great recent tutorial that builds a web app? |
| 10:16 | boxed | “web app” is a bit vague… the readme on https://github.com/weavejester/compojure does a fairly good job at the basics |
| 10:17 | xeranas | hello, Clojure is new thing to me. I trying to find way to redefine static variables for test. But probably fail to understand concept. Here how I tried: https://gist.github.com/xeranas/2bb3fd9b1508448ffd76 |
| 10:18 | Fare | xeranas, by the time you call B, it has already been evaluated |
| 10:18 | Fare | maybe you want (defn B [] A) instead? |
| 10:24 | xeranas | Fare: hmm, defn would do a trick. I probably should stick for defn while still learning |
| 10:26 | kandinski | hi, I'm new to clojure and emacs. I have installed cider following the instructions on braveclojure.org, but when I start the cider repl, I get this message: http://paste.ubuntu.com/7865976/ . Emacs packages do not include cider-nrepl. What am I doing wrong? |
| 10:29 | ProTip | Hi guys, I'm wanting to use rickshaw or d3js in a clojurescript project and I'm a bit confused on the current best way of doing this.. |
| 10:29 | ProTip | Do I need to generate and externs file? |
| 10:33 | deathknight | what is the name of "@" in clojure? having a hard time searching up what that means on google |
| 10:34 | deathknight | i.e. (let [post @upcoming-post-queue] ...) |
| 10:34 | H4ns | deathknight: deref |
| 10:35 | deathknight | thank you h4ns |
| 10:47 | itruslove | kandinski: add the cider-nrepl plugin to your ~/.lein/profiles.clj - see https://github.com/clojure-emacs/cider-nrepl |
| 10:49 | kandinski | itruslove, thanks |
| 10:56 | ProTip | Is this the prefered way to create externs? https://gist.github.com/Chouser/5796967/download# |
| 11:07 | dnolen_ | ProTip: https://github.com/federico-b/d3-externs |
| 11:08 | dnolen_ | ProTip: you can sometimes use the library itself as the externs file, http://swannodette.github.io/2014/03/14/externs-got-you-down/ |
| 11:08 | dnolen_ | ProTip: if you only use a couple of functions, writing the externs file is pretty simple. |
| 11:09 | ProTip | thx :D |
| 11:09 | ProTip | I've found out too that I can just use the library with the js explicitly loaded in the html page |
| 12:22 | reduced | Hey |
| 12:22 | reduced | Is anybody in there |
| 12:28 | sjouke | It's been awhile since I've looked at Clojure. IIRC, there was something about clojure which struck a chord with me: "a uniform API for accessing and manipulating data structures" |
| 12:29 | sjouke | Is this correct, would someone be willing to give me a search term, so I can look further into it? |
| 12:32 | jeremyheiler | sjouke: have you read through http://clojure.org/data_structures ? |
| 12:33 | jeremyheiler | actually, this one: http://clojure.org/sequences |
| 12:33 | jeremyheiler | the sequence abstraction is what you're talking about |
| 12:33 | jeremyheiler | is what i think* |
| 12:34 | sjouke | jeremyheiler: i haven't, i'll take a look at both :) |
| 12:34 | sjouke | reading the sequence one first of course, thanks jeremyheiler |
| 12:34 | jeremyheiler | np! |
| 12:40 | deathknight | how can I, in the REPL, (require ') a file called example.clj in ~/proj_dir/test/clj-facebook-graph/example.clj? |
| 12:42 | noidi | deathknight, http://grimoire.arrdem.com/1.6.0/clojure.core/load/ |
| 12:43 | noidi | deathknight, http://grimoire.arrdem.com/1.6.0/clojure.core/load_DASH_file/ |
| 12:43 | deathknight | Thank you noidi. Why does my computer lock up for about 10 seconds whenever someone mentions my name in the smuxi client? |
| 12:47 | sjouke | https://programmers.stackexchange.com/questions/214425/why-does-clojure-neglect-the-uniform-access-principle |
| 12:48 | sjouke | see last answer |
| 12:48 | sjouke | i'm a young programmer, i've been thinking private methods are security feature for languages |
| 12:49 | tbaldridge | sjouke: security...no. In Java you can access any private field via reflection |
| 12:49 | sjouke | then what's the point? |
| 12:49 | tbaldridge | sjouke: and if all data is immutable it doesn't matter, no one can change it |
| 12:49 | tbaldridge | that's just it, Rich is right, uniform access is a un-wanted "feature" |
| 12:49 | bbloom | tbaldridge: in theory you can disallow java code from using reflection w/ the security system, but nobody does really |
| 12:50 | bbloom | tbaldridge: the uniform access principal is about fields/properties/methods, not about private/public |
| 12:54 | sjouke | it seems private methods are for communicating to programmers using your code which functions they should use and which ones are implementation details |
| 12:54 | sjouke | that seems logical |
| 12:59 | devong | is it possible to execute common lisp in clojure? I'd like to be able to convert org-mode documents in html for this clojure app I'm writing. |
| 13:00 | jeremyheiler | devong: i suppose you could shell out |
| 13:01 | devong | hmm, that doesn't really seem like what I'm looking for. I think I'm going to need to just do more googling, this seems like something someone has probably already solved. |
| 13:01 | jeremyheiler | what are you asking for than? |
| 13:01 | jeremyheiler | then* |
| 13:01 | devong | I don't really need to call common lisp, what I really need is to find a clojure library for parsing org-mode documents |
| 13:01 | devong | :) |
| 13:01 | jeremyheiler | oh, well, that's different |
| 13:02 | devong | I just found a common lisp library, and thought, maybe there is an interopt somewhere |
| 13:02 | jeremyheiler | any sort of interop would likely just shell out |
| 13:03 | jeremyheiler | a quick search turned up this: https://github.com/gmorpheme/organum |
| 13:03 | devong | I think maybe something like this http://nakkaya.com/static.html |
| 13:04 | devong | your google foo is better than mine |
| 13:04 | devong | this morning |
| 13:04 | devong | thanks!! |
| 13:04 | jeremyheiler | lol "clojure org mode parser" ;-) |
| 13:04 | devong | IDK man, I had googled that |
| 13:04 | devong | and wasn't coming up with anything |
| 13:04 | devong | something must have been just a little different |
| 13:05 | devong | haha, oh well |
| 13:05 | jeremyheiler | heh. i suppose with google searches aren't consistent |
| 13:05 | jeremyheiler | anyway, i hope that works out for you |
| 13:06 | devong | regardless, thanks |
| 13:06 | jeremyheiler | np |
| 13:11 | sjouke | nobody disagreed |
| 13:11 | sjouke | i wasn't expecting that :) |
| 13:12 | sjouke | 11:51 < sjouke> it seems private methods are for communicating to programmers using your code which functions they should use and which ones are implementation details |
| 13:12 | sjouke | 11:51 < sjouke> that seems logical |
| 13:13 | jeremyheiler | sjouke: documentation can also do that |
| 13:14 | jeremyheiler | sjouke: sometimes it's not readily apparent which fns are impl details and which aren't |
| 13:14 | nobodyzzz | privacy is overrated - ask NSA :D |
| 13:18 | jeremyheiler | sjouke: specific to clojure, lets say you have a helper function that you want private and need in two namespaces. are you going to copy paste that function in both, combine the namespaces, or make it public in a util namespace? |
| 13:38 | sjouke | jeremyheiler: that makes sense |
| 13:45 | vdmit11 | Hi folks. Given an existing object, can I add an implementation of some protocol to this object? I mean, I would like to morph an object, before morphing it doesn't support a certain protocol, after the morphing - it does. Is there some way to do this? |
| 13:46 | bbloom | vdmit11: you want to define a protocol on a particular instance, not on all objects of that type? |
| 13:47 | vdmit11 | yes, on a particular instance |
| 13:47 | bbloom | clojurescript has the "specify" macro |
| 13:47 | bbloom | but nothing like that on the jvm |
| 13:48 | bbloom | if you have a small number of protocols to implement, i suggest using reify to create a delegating object |
| 13:48 | bbloom | or, back up a step and explain why you need this. there may be a better solution |
| 13:55 | vdmit11 | Well, I'm writing a little music-related program, I need to represent music somehow, so I decided to add a bunch of types like Note, Chord, Phrase, stuff like that, they have some properties in common like pitch or duration and they need to handle them in a different way, so I decided to write a bunch of protocols for such properties. Now, I need to "compose" some music, so I would like to add certain "effects" to those objects, like "vibrato". There must be a |
| 13:58 | vdmit11 | Actually these things like Note or Chord are abstract data types, they determined not by the name, but by a set of protocols they satisfy. I use reify to create them and satisfies? to check whether an object can behave like what I want, kinda duck typing. In the code, I can reify what I want from scratch, but in the runtime I would like to create improved version of existing instances, so I have this problem. |
| 14:00 | vdmit11 | Now I guess there is no better solution than runtime polymorphism, so I'm going to re-implement this stuff using multimethods and hashmaps. |
| 14:01 | Jaood | marco |
| 14:09 | ambrosebs | bbloom: any ideas on how to chaperone a deftype to add contracts to its methods? so far the best idea I have is to use java.lang.instrument to intercept the bytecode before it's defined and add pre/post things to the methods. |
| 14:09 | bbloom | ambrosebs: ha! you're getting crazy now :-P |
| 14:10 | ambrosebs | yes this is stupid |
| 14:10 | bbloom | i know nothing about java's instrumentation capabilities |
| 14:10 | bbloom | other than it's pretty good at it, as far as these things go |
| 14:10 | bbloom | it's important for profilers |
| 14:10 | ambrosebs | ahk. worth a try :) |
| 14:11 | bbloom | would be quite a feat if you make it work |
| 14:11 | bbloom | good luck :-) |
| 14:12 | ambrosebs | thanks! |
| 14:17 | schmee | how do I combine `with-open` and recursion? just call the function instead of using `recur`? |
| 14:19 | bbloom | schmee: presumably you don't want to open a file on each go of the recursion... |
| 14:20 | bbloom | but in general, if you want to recurse out of a catch or finally block, clojure/jvm can't promise constant stack space, so you need to call the function by name instead of recur, which enforces a tail call |
| 14:21 | bbloom | in your case, you probably just want to put a loop form inside your with-open |
| 14:22 | schmee | I solved my problem by splitting the function in two, but thanks for the help! |
| 14:22 | bbloom | schmee: yeah, that's essentially what loop would let you do w/o the split |
| 14:22 | bbloom | schmee: http://clojure.org/special_forms#Special Forms--(loop [bindings* ] exprs*) |
| 14:23 | bbloom | ambrosebs: what do you need to add to methods for "chaparones" ? |
| 14:23 | bbloom | chaperones, rather |
| 14:23 | schmee | bbloom: I tried using loop at first, that's when I got the error |
| 14:24 | bbloom | schmee: loop *inside* your with-open ? |
| 14:25 | schmee | bbloom: yep |
| 14:25 | bbloom | would have to see it |
| 14:27 | ambrosebs | bbloom: basically pre/post conditions that blame the correct party, also to add delayed checks to the return value of a method. |
| 14:27 | schmee | bbloom: I probably did something retarded, but either way it works now :) |
| 14:28 | bbloom | ambrosebs: i don't know anything about AspectJ, but it might be worth looking at |
| 14:28 | ambrosebs | bbloom: yes, having a glance. Not sure if I can get away with just using ASM, since it's already on my classpath. |
| 14:30 | bbloom | ambrosebs: logging is the only example anybody ever uses for aspect oriented programming :-P |
| 14:30 | ambrosebs | hehe |
| 14:33 | verma | in context of clojure async, when I do (<!! (timeout 3000)) my repl waits for 3 seconds, but when I do (<!! (go (timeout 3000))), it doesn't, it seems to me that even go runs in a different "thread" the <!! should still block the currrent threadn, it returns a ManyToManyChannel instead |
| 14:33 | verma | s/even go/even if go/ |
| 14:33 | bbloom | verma: read the doc string for go |
| 14:34 | bbloom | or maybe (<!! (<!! (go (timeout 3000)))) will be illustrative |
| 14:35 | verma | bbloom, I did read the docs, so go is returning the channel returned by (timeout 3000) |
| 14:35 | verma | oh |
| 14:36 | bbloom | verma: no |
| 14:36 | bbloom | go is returning a channel that will receive the timeout channel |
| 14:36 | bbloom | it's a channel of channels |
| 14:36 | bbloom | or a channel of channel. singular, ie a "promise" |
| 14:36 | verma | bbloom, hmmm, thinking ... |
| 14:37 | verma | bbloom, ok makes sense now |
| 14:37 | verma | thanks |
| 14:37 | verma | (inc bbloom) |
| 14:37 | lazybot | ⇒ 39 |
| 14:40 | bbloom | ambrosebs: what if you only chaperone functions? |
| 14:40 | bbloom | ambrosebs: that is, do you really need to blame at method boundaries? |
| 14:40 | bbloom | ambrosebs: or would it be sufficient to redefine functions? |
| 14:40 | drguildo | how do i debug a nullpointerexception? |
| 14:41 | drguildo | or debug exceptions in general |
| 14:41 | drguildo | the error messages i get aren't very useful |
| 14:41 | bbloom | drguildo: *e in your repl |
| 14:41 | bbloom | try (pst) too |
| 14:41 | bbloom | or (clojure.repl/pst) |
| 14:42 | ambrosebs | bbloom: yea I'm asking the same questions. Need to reread some papers. |
| 14:42 | schmee | bbloom: this function keeps recurring even when I type "quit", any idea why? |
| 14:43 | bbloom | ambrosebs: but http://www.eclipse.org/aspectj/doc/released/progguide/starting-aspectj.html does seem useful |
| 14:44 | bbloom | schmee: if the function is running, the repl isn't listening... try ctrl-c |
| 14:44 | drguildo | bbloom, thanks but that doesn't really give me any more information than i get already. how would i go about tracking down what it is that's being called in the fn to trigger the exception? |
| 14:44 | bbloom | drguildo: you follow the stack trace... it should have file/line information in it |
| 14:45 | drguildo | bbloom, it does but i'm having trouble finding out what it is on that line that's generating the exception. i'm a complete clojure beginner. |
| 14:46 | bbloom | drguildo: experiment with subexpressions in your repl |
| 14:46 | drguildo | i'm used to liberally peppering my code with print statements to track down bugs :-/ |
| 14:46 | drguildo | so i'm quite stumped |
| 14:46 | bbloom | drguildo: what's stopping you from doing that? |
| 14:47 | drguildo | bbloom, ignorance, i guess. i'm new to functional languages. |
| 14:48 | bbloom | drguildo: clojure is not pure, just use prn |
| 14:48 | bbloom | ,(let [x nil y :not-nill] (prn x y) :result) |
| 14:48 | clojurebot | nil :not-nill\n:result |
| 14:48 | bbloom | ,(def dbg [x] (prn x) x) |
| 14:48 | clojurebot | #<CompilerException java.lang.RuntimeException: Too many arguments to def, compiling:(NO_SOURCE_PATH:0:0)> |
| 14:48 | bbloom | ,(defn dbg [x] (prn x) x) |
| 14:48 | clojurebot | #'sandbox/dbg |
| 14:48 | bbloom | ,(inc (dbg 5)) |
| 14:48 | ambrosebs | bbloom: it does. do you know if that redefines entire classes or magically just swaps out a method? |
| 14:48 | clojurebot | 5\n6 |
| 14:49 | bbloom | ambrosebs: the wikipedia article lead me to believe that it uses java.lang.instrumentation and does byte code "weaving" |
| 14:49 | drguildo | like i just added a bunch of println to the fn before the line that causes the exception |
| 14:49 | drguildo | but when i execute the problem function in the repl, nothing gets printed |
| 14:49 | ambrosebs | bbloom: ah. niiice |
| 14:50 | drguildo | i just get the exception like before |
| 14:50 | drguildo | same if i use prn |
| 14:50 | jeremyheiler | drguildo: did you reload the function? |
| 14:51 | drguildo | jeremyheiler, i think so. i did ctrl-c ctrl-k and also ctrl-x e |
| 14:52 | ambrosebs | bbloom: one thing that made me sad is that you can't hook into a primitive array get/set |
| 14:52 | ambrosebs | at least, no one has implemented it yet afaik |
| 14:52 | bbloom | ambrosebs: hook the aget and aset functions |
| 14:53 | schmee | bbloom: yeah, ctrl-c works, but I still don't understand why typing "quit" doesn't |
| 14:53 | bbloom | schmee: repl == read, eval, print, loop |
| 14:53 | schmee | typing "quit" in with a print added will print "running? false"! https://gist.github.com/schmee/7128ad47b35576187e86 |
| 14:53 | bbloom | it was doing eval/print, it hadn't looped back to read yet |
| 14:54 | bbloom | schmee: oh, i thought you were talking about the repl, not your custom socket thing |
| 14:54 | drguildo | https://www.refheap.com/88616 |
| 14:54 | drguildo | what am i doing wrong? |
| 14:54 | ambrosebs | bbloom: yea I might consider that. would be nice to actually have a guarantee of some sort, instead of hoping the array doesn't get passed to evil java worlds |
| 14:55 | ambrosebs | I'm erring on the all-or-nothing for now :) |
| 14:55 | bbloom | drguildo: you might be being bitten by laziness |
| 14:55 | drguildo | story of my life |
| 14:55 | bbloom | heh |
| 14:55 | drguildo | how do i get around it? |
| 14:56 | bbloom | drguildo: map is lazy, side effects in the transformation function aren't promised to run at any particular time |
| 14:56 | drguildo | i use do or something like that? |
| 14:56 | bbloom | it just means that your function isn't running |
| 14:56 | bbloom | ,(first (map println [1 2 3])) |
| 14:56 | clojurebot | 1\n2\n3\n |
| 14:56 | bbloom | notice all three run |
| 14:56 | bbloom | but: |
| 14:56 | bbloom | ,(first (map println (range 100))) |
| 14:56 | clojurebot | 0\n1\n2\n3\n4\n5\n6\n7\n8\n9\n10\n11\n12\n13\n14\n15\n16\n17\n18\n19\n20\n21\n22\n23\n24\n25\n26\n27\n28\n29\n30\n31\n |
| 14:56 | bbloom | only 32 run |
| 14:57 | bbloom | there's no promise of how much of the lazy sequence will be visited |
| 14:57 | bbloom | which means your exception is coming from somewhere else |
| 14:57 | boxed | w00t, got clj-time to use my midje-readme plugin |
| 14:58 | bbloom | ambrosebs: isn't the entire point of blame to handle flexible boundaries between verification techniques? |
| 14:58 | drguildo | bbloom, so how do i find out where? |
| 14:58 | bbloom | drguildo: heh, more print statements |
| 14:58 | drguildo | :-( |
| 14:59 | bbloom | drguildo: what's the matter, you said you like print statements? |
| 14:59 | bbloom | you learned somethign when NOTHING was printed: you learned that your map code isn't being traversed anywhere |
| 14:59 | bbloom | that means your NPE is happening before the result of map is used |
| 14:59 | bbloom | you've narrowed the search space |
| 14:59 | bbloom | keep going :-) |
| 15:02 | schmee | how is it possible to have (when running (prinln running)) print "false"...... |
| 15:05 | bbloom | (prn (class false)) |
| 15:05 | bbloom | or rather (prn (class running)) |
| 15:05 | drguildo | so why is the exception triggered on that line? |
| 15:05 | drguildo | and doesn't that make clojure really hard to debug? |
| 15:05 | ambrosebs | bbloom: java arrays seem like the bane of my existence for the last few years. I'll have to think about that. |
| 15:06 | bbloom | drguildo: have you tried printing all the the variables that are inputs to that line? |
| 15:06 | bbloom | ambrosebs: why? |
| 15:06 | drguildo | bbloom, i'm pretty sure i've tracked down the problem; i'm just asking a question about clojure in general |
| 15:06 | gfredericks | ,(def my-false (Boolean. false)) |
| 15:06 | clojurebot | #'sandbox/my-false |
| 15:07 | gfredericks | ,(when my-false (println my-false)) |
| 15:07 | clojurebot | false\n |
| 15:07 | bbloom | drguildo: small, pure functions are much much easier to debug than large stateful rats nests |
| 15:07 | schmee | running class java.lang.Boolean <-- good or bad? |
| 15:07 | gfredericks | schmee: running it? |
| 15:07 | ambrosebs | bbloom: array types in core.typed still don't really work |
| 15:08 | schmee | gfredericks: huh? |
| 15:08 | bbloom | schmee: are you using zmq? |
| 15:08 | gfredericks | schmee: ooh sorry I think I misinterpreted |
| 15:08 | bbloom | ,(identical? false false) |
| 15:08 | clojurebot | true |
| 15:08 | ambrosebs | bbloom: I experimented with bivariant arrays and ... still experimenting |
| 15:08 | bbloom | ,(identical? false (Boolean. false)) |
| 15:08 | clojurebot | false |
| 15:08 | bbloom | schmee: maybe the library you're using is giving you a bad boolean ^^ |
| 15:09 | gfredericks | schmee: yeah compare it to `false` using `identical?` as bbloom suggested |
| 15:09 | gfredericks | ,my-false |
| 15:09 | clojurebot | false |
| 15:09 | gfredericks | ,(identical? my-false false) |
| 15:09 | clojurebot | false |
| 15:09 | gfredericks | ,(identical? (Boolean/valueOf my-false) false) |
| 15:09 | clojurebot | true |
| 15:09 | bbloom | drguildo: also all your data being printable/readable makes it *very easy* to inspect intermediate results with a pretty printer |
| 15:09 | gfredericks | ,(identical? (boolean my-false) false) |
| 15:09 | clojurebot | true |
| 15:10 | gfredericks | schmee: you can pass a dirty Boolean to the boolean function to get back a good value; not sure how you ended up with such a thing |
| 15:10 | drguildo | bbloom, so in general is clojure easier, the same, or more difficult to debug? |
| 15:10 | drguildo | like is it just a case of me getting used to it |
| 15:10 | bbloom | gfredericks: probably from a broken socket library |
| 15:10 | bbloom | drguildo: i find it dramatically easier to debug, but it requires a very different workflow |
| 15:11 | bbloom | drguildo: that doesn't mean that things like stepping debuggers are never useful, and there are some cases where tooling in clojure is far from sufficient |
| 15:11 | schmee | I don't think it's boolean, but something with the recursion in this function isn't right... https://gist.github.com/schmee/7128ad47b35576187e86 |
| 15:11 | drguildo | bbloom, is there anything i can read that will help or is it just a case of experience? |
| 15:12 | bbloom | drguildo: mostly experience, but people can give specific hints |
| 15:12 | bbloom | in general, just get used to working in your repl and evaluating forms from your buffer |
| 15:13 | bbloom | you'll write better code that way too, b/c you'll write & test smaller bits of code at a time |
| 15:13 | bbloom | and if you type test expressions in to your buffers instead of your repl, then you'll have extra test cases lying around to try when something goes wrong |
| 15:14 | drguildo | cool. thanks. |
| 15:17 | onr | could you recommend a concise resource for java standard library? |
| 15:17 | bbloom | concision isn't really java's thing... |
| 15:21 | jeremyheiler | onr, are you looking for the javadocs? |
| 15:23 | onr | jeremyheiler: oh javadocs seems to be what i need |
| 15:23 | gfredericks | schmee: the recursion looks fine; what about the first call to the function? |
| 15:23 | jeremyheiler | onr, i usually get to them by searching "java 7 api" and optionally the class i care about |
| 15:24 | schmee | gfredericks: I've added it to the gist: https://gist.github.com/schmee/7128ad47b35576187e86 |
| 15:24 | schmee | I start by typing `join "user"` in the REPL |
| 15:25 | onr | jeregrine: did you read a java for getting started using java std lib? |
| 15:25 | gfredericks | schmee: are you planning on making this more complex? as it stands the `running` arg is a bit redundant isn't it? |
| 15:25 | jeregrine | onr :) |
| 15:25 | jeremyheiler | onr, not sure what you mean |
| 15:26 | onr | jeremyheiler i mean :) |
| 15:26 | onr | oh, i intended to ask, did you read a java *book* to learn about java standard library |
| 15:27 | schmee | gfredericks: well, in the REPL I can just ctrl-c out, but I need a way to quit if I'm not running it from the REPL |
| 15:27 | schmee | and I still don't get why it just doesn't work |
| 15:30 | gfredericks | schmee: replace line three with (prn [running (class running) (identical? running false)]) and let us know what it prints |
| 15:30 | jeremyheiler | onr, not really. |
| 15:30 | jeremyheiler | onr, mostly learned by doing |
| 15:33 | schmee | gfredericks: waaaaaaiiiit a minute... when (msg-loop socket user false) has returned, will the execution resume from that point? |
| 15:33 | gfredericks | schmee: oh whoops. yes it will. |
| 15:34 | schmee | oh snap |
| 15:34 | schmee | how do I avoid that? |
| 15:34 | gfredericks | (if (= msg "quit") (do ...) (do ...)) |
| 15:38 | schmee | gfredericks: worked perfectly, thanks a ton! |
| 15:50 | schmee | is it idiomatic in clojure to use `future` instead of spawn a new Thread, even if the function doesn't return a value? |
| 15:50 | schmee | *spawning |
| 15:51 | weavejester | schmee: I tend to do it - I don’t believe there are many disadvantages to the approach |
| 15:51 | weavejester | It uses a thread pool, but not one that can be exhausted |
| 15:52 | schmee | so (doto (Thread. (client sock true)) (.start)) |
| 15:52 | schmee | and (future (client sock true)) |
| 15:52 | schmee | are basically interchangable? |
| 15:53 | weavejester | Yessss… They do different things under the hood |
| 15:53 | weavejester | future uses a thread pool, IIRC |
| 15:53 | erdos | hello, i am looking for a way to serialize a long seq, buf pr-str, print-str, print, pprint/pprint all cut my list after 100 elems. any ideas? thank you. |
| 15:53 | weavejester | But for most purposes I believe they can be used interchangeably. |
| 15:54 | schmee | weavejester: great, thanks |
| 15:54 | weavejester | erdos: pr-str does? I know that REPLs can limit the number of elements, but pr-str shouldn’t be affected… |
| 15:54 | jeremyheiler | weavejester, schmee futures use the same threadpool as send-off uses for agents, |
| 15:55 | weavejester | jeremyheiler: Yeah |
| 15:55 | jeremyheiler | so blocking activity is cool |
| 15:55 | weavejester | erdos: http://clojuredocs.org/clojure_core/clojure.core/*print-length* |
| 15:56 | jeremyheiler | schmee: with futures you get a higher level api from clojure to manage them. |
| 15:56 | erdos | weavejester, thank you. the docs says, "The root binding is nil indicating no limit." |
| 15:56 | weavejester | erdos: Yeah, *print-length* does affect pr-str. Are you seeing “…” at the end of your printed data? |
| 15:57 | TimMc | hyPiRion, technomancy: OK, OK, I've picke dup Hyperion from the library. :-P |
| 15:58 | erdos | weavejester: exactly |
| 15:58 | weavejester | erdos: You might want to check the value of *print-length* in your REPL |
| 16:00 | erdos | weavejester: thank you. it was bound to 100. |
| 16:01 | weavejester | erdos: Mystery solved :) |
| 16:21 | gfredericks | is it weird that clojure doesn't have a simple mechanism to start a function after a delay? |
| 16:21 | gfredericks | I assume (future (Thread/sleep ...) ...) is unideal |
| 16:22 | _clearwater | hi. learning programming. what language/core library will I like if i like the simplicity and light-weightness of javascript, but for the server. i can't wrap my head around async and clojure has simple syntax but too heavy to install |
| 16:22 | gfredericks | _clearwater: clojure is heavy to install? |
| 16:24 | _clearwater | i have no idea how java works. not a CS major, so don't know about threads etc. but would like to. |
| 16:24 | jeremyheiler | gfredericks: there is clojure.core/delay |
| 16:24 | jeremyheiler | it doesn't give you a timeout, tho |
| 16:26 | gfredericks | jeremyheiler: that's completely different |
| 16:27 | gfredericks | I'm talking about scheduling |
| 16:27 | gfredericks | _clearwater: okay, well I can't imagine clojure being much more difficult to "install" than anything else. You need to install a JDK and then download the leiningen script. |
| 16:30 | jeremyheiler | gfredericks: i didn't mean timeout, sorry. either way, i see what you mean. i suppose something nice coudld be wrapped around java.util.concurrent.ScheduledExecuterService with j.u.c.Delayed |
| 16:31 | gfredericks | well if you have an executor service you don't really need anything else |
| 16:31 | gfredericks | a scheduled executor service rather |
| 16:31 | gfredericks | ,(java.util.concurrent.Executors/newSingleThreadScheduledExecutor) |
| 16:31 | clojurebot | #<DelegatedScheduledExecutorService java.util.concurrent.Executors$DelegatedScheduledExecutorService@99823> |
| 16:32 | gfredericks | ,(def my-pool (java.util.concurrent.Executors/newSingleThreadScheduledExecutor)) |
| 16:32 | clojurebot | #'sandbox/my-pool |
| 16:32 | gfredericks | ,(def my-num (atom 0)) |
| 16:32 | clojurebot | #'sandbox/my-num |
| 16:32 | gfredericks | ,(.schedule my-pool #(swap! my-num + 42) 2 java.util.concurrent.TimeUnit/SECOND) |
| 16:32 | clojurebot | #<CompilerException java.lang.RuntimeException: Unable to find static field: SECOND in class java.util.concurrent.TimeUnit, compiling:(NO_SOURCE_PATH:0:0)> |
| 16:33 | gfredericks | ,(.schedule my-pool #(swap! my-num + 42) 2 java.util.concurrent.TimeUnit/SECONDS) |
| 16:33 | clojurebot | #<SecurityException java.lang.SecurityException: no threads please> |
| 16:33 | gfredericks | clojurebot: sure okay thamks |
| 16:33 | clojurebot | No entiendo |
| 16:33 | schmee | if I want to store messages in a chat server, should I use an atom or an agent? |
| 16:34 | gfredericks | schmee: my guess is an atom is fine |
| 16:36 | jeremyheiler | gfredericks: i meant that it could be nicely hooked into deref and whatnot |
| 16:36 | jeremyheiler | oh, maybe not necessary . i see j.u.c.Future is special cased |
| 16:37 | gfredericks | yep; you gotta be careful with that interface though |
| 16:38 | gfredericks | the reflector likes to guess wrong between the Runnable/Callable choice |
| 16:39 | jeremyheiler | heh. what happens when it guesses wrong? |
| 16:39 | gfredericks | a future that returns nil |
| 16:43 | jeremyheiler | ah, that makes sense. |
| 17:29 | hyPiRion | (inc TimMc) |
| 17:29 | lazybot | ⇒ 64 |
| 17:48 | expez | https://www.refheap.com/88618 when you're interatively building up the result of a macro, is this the way to go? |
| 17:52 | jeremyheiler | expez: what do you want the macro to do, ultimately? |
| 17:57 | jeremyheiler | expez: if you want it to return a constant that is the sum of nums, then you're not doing that. but if it's just illustrative for larger problem, then i'm not sure what you're asking. |
| 17:57 | expez | The actual macro I'm writing is instrumenting some functions, so it takes a seq of fns and then should expand to a bunch of (add-hook #'fn some-hook) along with some other stuff |
| 17:57 | jeremyheiler | ah, ok. |
| 17:58 | expez | I was wondering how I would go about building up the list of ((add-hook...) ...) that I would later splice into the macro result |
| 17:58 | jeremyheiler | use for |
| 17:59 | jeremyheiler | ,(for [f [inc dec]] `(~f 1)) |
| 17:59 | clojurebot | ((#<core$inc clojure.core$inc@ffdb99> 1) (#<core$dec clojure.core$dec@3c67e> 1)) |
| 17:59 | jeremyheiler | it takes a seq and returns a seq |
| 18:00 | expez | right, that is way more elegant |
| 18:00 | expez | thanks |
| 18:00 | jeremyheiler | it's also lazy, so keep that in mind |
| 18:01 | expez | Won't the compiler realize it for me at macro expansion time? |
| 18:02 | jeremyheiler | with out trying it out myself, i'm not sure. |
| 18:07 | timsg | Is there a predicate to test whether something’s seq-able? |
| 18:08 | jeremyheiler | ,(doc seq?) |
| 18:08 | clojurebot | "([x]); Return true if x implements ISeq" |
| 18:08 | jeremyheiler | ,(doc sequence?) |
| 18:08 | clojurebot | No entiendo |
| 18:08 | jeremyheiler | ,(doc sequential?) |
| 18:08 | clojurebot | "([coll]); Returns true if coll implements Sequential" |
| 18:09 | jeremyheiler | hmm |
| 18:10 | gfredericks | timsg: there's an interface called Seqable but that misses a few special cases |
| 18:10 | timsg | ,(clojure.set/intersection (ancestors (type {})) (ancestors (type '()))) |
| 18:10 | clojurebot | #<ClassNotFoundException java.lang.ClassNotFoundException: clojure.set> |
| 18:10 | gfredericks | like nil, strings, arrays |
| 18:10 | gfredericks | probably something else I'm not thinking of |
| 18:11 | timsg | oops, new to this repl. Is it possible to refer to another namespace? |
| 18:11 | gfredericks | ,(def my-list (doto (java.util.LinkedList.) (.add 3) (.add 99))) |
| 18:11 | clojurebot | #'sandbox/my-list |
| 18:11 | gfredericks | ,(seq my-list) |
| 18:11 | clojurebot | (3 99) |
| 18:11 | timsg | gfredericks, jeremyheiler: clojure.lang.Seqable looks promising |
| 18:12 | gfredericks | I'm checking the java source now for all the exceptions |
| 18:12 | gfredericks | nil, Iterable, Array, CharSequence, and Map |
| 18:12 | gfredericks | timsg: ^ |
| 18:13 | timsg | gfredericks: thanks. What’s the ^? |
| 18:15 | jeremyheiler | it's kind of a bummer that there isn't a predicate for this |
| 18:17 | timsg | gfredericks: ah, caret as in yes Seqable :-| |
| 18:18 | gfredericks | timsg: the caret was pointing to the previous thing I had said |
| 18:19 | hyPiRion | TimMc: I can't PM you without being logged in. |
| 18:20 | timsg | gfredericks: yup, thanks :) |
| 18:20 | timsg | gfredericks, jeremyheiler: here’s an old implementation: http://clojuredocs.org/clojure_contrib/clojure.contrib.core/seqable_q |
| 18:20 | gfredericks | ,(defn seqable? [x] (or (nil? x) (.isArray (class x)) (condp instance? x clojure.lang.ASeq clojure.lang.LazySeq clojure.lang.Seqable Iterable CharSequence java.util.Map))) |
| 18:20 | clojurebot | #'sandbox/seqable? |
| 18:21 | gfredericks | ,(map seqable? ["okay" () nil 7 :foo]) |
| 18:21 | clojurebot | #<IllegalArgumentException java.lang.IllegalArgumentException: No matching clause: 7> |
| 18:22 | gfredericks | that's definitely not how to use condp |
| 18:23 | jeremyheiler | lol |
| 18:25 | hyPiRion | (some #(instance x %) [...]) instead |
| 18:25 | hyPiRion | although I never remember the ordering |
| 18:26 | jeremyheiler | http://dev.clojure.org/jira/browse/CLJ-401 |
| 18:30 | TimMc | hyPiRion: Huh, OK. I thought most people were registered. Let me fix that. |
| 18:31 | hyPiRion | TimMc: Right, I am, just temporarily unable to login for some reason |
| 18:41 | jeremyheiler | as did i |
| 18:41 | jeremyheiler | left a comment... seems like the contrib version differs only slighly than RT.seqFrom |
| 19:26 | wildnux | hi |
| 19:26 | wildnux | what is the best way to check for root access in linux in clojure |
| 19:48 | TimMc | wildnux: It's not going to be Clojure specific. You'll either use some library or issue shell calls. |
| 19:51 | TimMc | (So broaden your search to Java libraries as well.) |
| 20:01 | wildnux | TimMc: doing that.. but so far i just found out only either reading current user (which could be change using jvm option) or using shell or process to run "$uid".. but it also does not give me the correct solution.. it does not give effective uid |
| 20:23 | TimMc | Why do you need it, by the way? |
| 20:28 | vdmit11 | Hi folks, is there an idiomatic way for naming "getter" and "setter" methods. For example, I define getter as: (fn [map] (:key map)) and "setter" as: (fn [map val] (assoc coll :key val), how should I name these functions? |
| 20:29 | jeremyheiler | vdmit11: why do you want to name them? |
| 20:30 | jeremyheiler | the bodies are very idiomatic and succinct. |
| 20:30 | vdmit11 | because they are abstract method names; and there are several implementations of these methods, some of them do things more complex than get/assoc |
| 20:30 | jeremyheiler | oh, sorry. you literally meant methods. |
| 20:31 | jeremyheiler | why not just get-foo and set-foo? |
| 20:32 | jeremyheiler | using "set" is kind of weird for the persistent structures tho |
| 20:33 | vdmit11 | yes, also it may confuse you if you reverse the name like foo-get foo-set foo-delete, etc, you may think that the foo-set is a data structure |
| 20:34 | vdmit11 | that is why I'm asking |
| 20:34 | vdmit11 | perhaps there is a convenient way |
| 20:34 | vdmit11 | conventional |
| 20:36 | TEttinger | well set-foo would just return a new foo |
| 20:36 | TEttinger | it wouldn't change the old one |
| 20:38 | TimMc | "with" is a prefix I've seen used for builder methods in Java |
| 20:40 | vdmit11 | all "set" occurrences in the clojure APIs are about side effects or sets (data structures), so I think the "set" will be a bit confusing |
| 20:42 | whigmaleerie | possible: (defn assoc-key [map value]) |
| 20:42 | vdmit11 | "with" is usually used by macros, I think it is a bit confusing too |
| 20:42 | whigmaleerie | whatever key might be |
| 20:43 | vdmit11 | I'd like assoc, but doesn't it implies "associate something with something", like I must pass both key and value? |
| 20:44 | vdmit11 | function and variable names are always painful for me :) |
| 21:21 | ProTip | I had a hell of a time figuring out that I missed the :require-macros in the om tutorial. All the error's pointed to .js files and nothing seemed to indicate the issue was with the "go" macro not existing... |
| 21:21 | ProTip | Am I doing something wrong? |
| 21:21 | ProTip | In regards to debugging that is, haha |
| 21:43 | kristof | vdmit11: This is a weird dilemma to have. |
| 21:43 | kristof | vdmit11: What are your data structures, anyway? |
| 21:52 | gfredericks | ProTip: what sort of error msg was it? |
| 22:25 | ruzu | (newbie q) if one was to design a pet language for the jvm, is clojure well suited to building the compiler? |
| 22:27 | TEttinger | ruzu: strongly typed or dynamic? |
| 22:27 | TEttinger | clojure is good for making clojuresque languages |
| 22:28 | TEttinger | but the core data structures are a certain way, and you might have to work around them if your language wasn't close to clojure |
| 22:28 | TEttinger | XText looked interesting |
| 22:28 | TEttinger | $google eclipse xtext |
| 22:28 | lazybot | [Xtext - Language Development Made Easy! - Eclipse] http://www.eclipse.org/Xtext/ |
| 22:28 | ruzu | mm |
| 22:28 | ruzu | i was thinking something ml-esque |
| 22:30 | lpvb | do swap! compare-and-set! and !reset block? |
| 22:31 | gfredericks | yep |
| 22:34 | ruzu | is xtext akin to antlr? |
| 22:36 | TEttinger | ruzu, I have looked at it, it makes an IDE plugin for you with syntax hightlighting and autocomplete. you can make your own language in whatever and hook it up to that |
| 22:36 | TEttinger | it also has a basic compiler it generates I think |
| 22:37 | jeremyheiler | gfredericks: internally atoms use an AtomicReference. this is inherently non-blocking, no? |
| 22:40 | gfredericks | wat? |
| 22:41 | gfredericks | jeremyheiler: why would AtomicReference be non-blocking? |
| 22:41 | gfredericks | http://docs.oracle.com/javase/7/docs/api/java/util/concurrent/atomic/AtomicReference.html#compareAndSet%28V,%20V%29 |
| 22:41 | gfredericks | ^ says nothing about being non-blocking |
| 22:43 | nathan7 | gfredericks: I'm pretty sure that's implemented as a single CAS pointer set in assembly-land. |
| 22:43 | nathan7 | gfredericks: If so, no, it wouldn't block. |
| 22:43 | gfredericks | maybe we're confusing terminology |
| 22:43 | gfredericks | I mean that it does everything it's going to do before it returns |
| 22:43 | gfredericks | and swap! in particular can sit there spinning arbitrarily long |
| 22:43 | jeremyheiler | ah, ok, then yes. i meant what nathan7 said. it doesn't use locks |
| 22:44 | nathan7 | oh, yeah |
| 22:44 | gfredericks | so I might be using "block" loosely |
| 22:44 | nathan7 | swap! is CAS in a loop |
| 22:44 | gfredericks | it's certainly not async like send |
| 22:44 | gfredericks | is really all I meant |
| 22:44 | nathan7 | well, send does some kind of atomic queue addition |
| 22:44 | nathan7 | the queue addition is blocking |
| 22:44 | nathan7 | probably also involving some atomic CAS in a loop |
| 22:45 | nathan7 | but the loop doesn't include the supplied fn, no |
| 22:45 | gfredericks | right |
| 22:45 | gfredericks | the fn gets called on another thread |
| 22:45 | jeremyheiler | nathan7: that's for agents, tho |
| 22:45 | nathan7 | jeremyheiler: what else does send accept? |
| 22:46 | nathan7 | jeremyheiler: because over here, send's first arg is ^clojure.lang.Agent a |
| 22:46 | jeremyheiler | right, the fns in question originally were for atoms. was confused. |
| 22:59 | rs0 | what would constitute a purely functional, dynamically typed programming language? |
| 23:00 | rs0 | suppose you had a Clojure-like language where referential transparency and the lack of side effects were enforced at runtime. if you attempted to, say, access the disk or generate a random number outside of a function whose name ended in a ! (even transitively), it was a runtime error. would that be a purely functional language? |
| 23:09 | TEttinger | rs0: a truly pure language is one that has no ability to modify the world outside it, not even the console or repl. does that sound useful to you? |
| 23:12 | benkay | is this (https://groups.google.com/forum/#!topic/datomic/UX4kNT0kaqg) still the best way to get empty attrs out of datomic? |
| 23:15 | Fare | I see a documentation page for cond-let, but its github file seems to be disappeared. |
| 23:15 | Fare | I know it's only a 3-line macro, but is there a standard place it has moved to? |
| 23:15 | benkay | is if-let the new hotness? |
| 23:17 | Fare | cond-let chains several if-lets |
| 23:17 | Fare | without having to nest heavily |
| 23:18 | Fare | otherwise, I suppose some kind of nesting macro could do it. Maybe a <- reply to -> ? |
| 23:23 | csd_ | Hello. How do I change the default directory where Lein creates new projects? |
| 23:26 | Fare | (defmacro <- "Nesting macro" ([] nil) ([x] x) ([x & y] `(~@x (<- ~@y)))) ;; like UIOP:NEST in CL |
| 23:31 | rs0 | TEttinger: Haskell is generally described as a purely functional language. do you think the term "purely functional" is well defined? |
| 23:32 | jeremyheiler | csd_: "lein help new" shows you how ;-) |
| 23:33 | rs0 | TEttinger: (personally, I have the sneaking suspicion that "purely functional" is no more rigorously defined than "object oriented", but I might be wrong) |
| 23:34 | csd_ | jeremyheiler: I see that I can set --to-dir when creating a project, but is there any way to put it into a profile so it's automatic? |
| 23:34 | TEttinger | rs0, I think it's generally accepted that true purity is a program that makes your CPU warmer and prints nothing. Haskell lets you break out of purity with monads, and it obviously is a usable language, so I think "purely functional" more refers for the ability to verify whether a function will have side effects |
| 23:34 | TEttinger | like in C, there's just no way to tell if a program will mutate outside state or not |
| 23:35 | rs0 | TEttinger: yes, that's what I'm getting at. I'm starting to think that the use of the IO monad in Haskell is just an elaborate type-oriented scheme for being able to determine whether functions have side effects or violate referential transparency |
| 23:35 | TEttinger | in clojure, it's easier if you stick to pure clojure... but there are still java interop things and even stuff like ##(rand-nth [1 2 3]) |
| 23:35 | lazybot | ⇒ 2 |
| 23:37 | rs0 | another idea in Haskell is pervasive non-strict evaluation. it appears to be one of the problems with unsafePerformIO--that, and the fact that the compiler is liable to perform incorrect optimizations when unsafePerformIO is used, and you have to use a bunch of pragmas and the like to try to ensure that your side effects don't get CSE'd out in a way you didn't intend or expect |
| 23:38 | rs0 | so in Haskell all these ideas are combined, and I think it's an interesting thought experiment to try to cut Haskell up into pieces and recompose the pieces in different ways, asking, "is this purely functional? how about now?" |
| 23:38 | TEttinger | indeed! |
| 23:39 | jeremyheiler | csd_: hmm, there doesn't appear to be any other way |
| 23:39 | jeremyheiler | the code just pulls that option from the arglist and that's it |
| 23:40 | csd_ | hrm ok |
| 23:42 | jeremyheiler | csd_: the code binds a *dir* var before it applies the template, so you may be able to create a custom template that overrides that behavoir? but that seems like a little much. |
| 23:43 | csd_ | just curious, do you choose to let it clutter up your home directory or use the flag each time |
| 23:44 | jeremyheiler | i just cd to the dir i want the project to be in. |
| 23:44 | csd_ | ok thanks |
| 23:44 | jeremyheiler | np |