#clojure log - Jun 20 2009

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0:45 blbrown_win2_: if you do a compile, is gen-class really needed?

0:51 replaca: blbrown_win2_: only if you want to create a named Java class

0:54 blbrown_win2_: replaca, what is a named Java class, one that doesn't use some non standard naming convention

0:55 http://clojure.org/compilation well I guess it is in the docs

0:57 replaca: blbrown_win2_: no, any class with methods that can be called from java in the normal way

0:57 blbrown_win2_: are you a java guy?

0:57 hiredman: blbrown_win2_: the classes generated by clojure have some gensym'ed name, so it is hard to new them up, because you need to know the name for new to work

0:57 blbrown_win2_: replaca, yea

0:57 hiredman: with gne-class you can specify a name

0:57 blbrown_win2_: sounds like it is not required and like you said, useful for using clojure from java

0:58 replaca: so if you want to create a class that you could easily use 'v = new MyClass()', b.bar(), etc. then you need gen-class

0:58 but usually when you're just writing clojure code, gen-class is not only unnecessary, but bad form

0:59 but if you need it, you need it

1:03 in other news, I *hate* classpaths!

1:05 blbrown_win2_: what is wrong with classpath

1:06 seems pretty simple you have a list of jars, you list them

1:07 replaca: it's just a pain to track everything

1:08 plus, what i'm doing doing, i'm building jars while I'm using them so I have to munge it on the fly

1:08 compared to python, ruby, .net, etc. it just seems to get in the way more

1:09 (though .net has some huge nastiness when you try to get tricky)

1:09 blbrown_win2_: I wish you could track which jar a class was loaded from

1:10 seem like that would be an issue thing to do, with the jar command, java should inject some kind of filepath signature from where the jar was built or something

1:10 replaca: it's just one of those things I seem to spend an inordinate amount of time worrying about and I never really think about it in any other language I use

1:10 blbrown_win2_: yeah, that would be a nice feature

1:11 samuels`: hey d00ds

1:11 blbrown_win2_: there are a couple of things I like about it. For example, with my application now, I wrote a custom class loader. Where i click on one jar and it (the java code) automatically finds the jars needed. Kind of like maven but working off the filesystem

1:11 replaca, people seem to have classpath issues if they use the default global classpath

1:14 tgevaert: quit

1:15 heh

1:15 /quit

1:15 replaca: blbrown_win2_: yeah, it can be powerful in cases like that, no doubt. I always make a custom one, cause there seems to be no useful default one. But I still seem to spend an unusual amount of time mucking with it.

1:16 hey samuels`

1:16 welcome

1:17 blbrown_win2_: replaca, yea. actually there was one issue where I had a classnotdeferror and for the life of me couldn't figure it out

1:17 samuels`: replaca: what shall we talk about

1:17 blbrown_win2_: wtf is the difference between classnotfound and classnotdef...never did figure that one

1:18 replaca: samuels`: I don't know. I'm hacking up the new autodoc robot for clojure-contrib

1:18 blbrown_win2_: I don't want to figure things like that out either! :-)

1:19 samuels`: replaca: have you seen "the hangover" ?

1:19 replaca: samuels`: not yet. heard it was good though

1:20 it kind of scares me!

1:20 samuels`: why?

1:21 out of interest

1:21 blbrown_win2_: guess it depends if you are a drinker or not...im a drinker, except for tonight

1:21 samuels`: where does the 'j' in clojure come from?

1:21 java?

1:21 replaca: I get a wicked headache just thinking about the premise. A few too many mornings like that

1:21 samuels`: hehehe

1:21 replaca: java and a pun on the zh sound in closure

1:21 samuels`: ah ok

1:22 btw is TCO slated for the jvm any time soon?

1:23 replaca: samuels`: not too soon it seems. Rumors keep starting, but not substantiated. Rich didn't sound too optimistic in the short-term lasd I heard

1:23 *last

1:24 samuels`: ok thx

1:24 replaca: don't find it bothers me too much, though, in practice

1:25 (not that I wouldn't like to have it)

1:25 slashus2: recur works fine

1:26 replaca: yeah, not a purdy, but that doesn't bother me much

1:26 *not as

1:27 slashus2: I like explicit.

1:28 replaca: I get that argument

2:22 blbrown_win2_: In the clojure code, what is a call to Var.deref? Is that when you reference a variable not a local variable . E.g. (def abc 1) (println abc)

2:27 replaca: blbrown_win2_: I don't think I understand the question

2:28 Actually, reading more closely, the answer is yes

2:28 blbrown_win2_: http://gnuvince.wordpress.com/2009/05/11/clojure-performance-tips/ I was reading this blog and he mentions deref. When is the jvm Var.deref called

2:29 replaca: ahh, yes. That's when Var.deref is called.

2:29 blbrown_win2_: (let [abc 1] (println abc) . is jvm: Var.deref called here

2:30 replaca: blbrown_win2_: no, abc is not a Var in that case

2:30 vars are always created with def or one of its derivitives

2:31 and can then be bound with binding

2:31 blbrown_win2_: like in the blog, I wonder why there is a penalty for using deref as opposed to local variables

2:35 replaca: because they are bound thread locally and the language needs to do a lookup through a special per thread structure

2:36 my battery just died, which means it's time to crash for me, too!

2:36 good night all!

2:51 blbrown_win2_: replaca, still there? wanna see something cool

3:01 http://spreadsheets.google.com/pub?key=rNB3pttScIyEdLM_kp2rejg&gid=4

3:16 cp2: neat

3:20 blbrown_win2_: here is the app I was testing. http://code.google.com/p/lighttexteditor/ code is not idiomatic which is probably why I am seeing issues

9:04 Chouser: there was talk of writing up a style guide -- that hasn't happened, right?

9:14 rhickey: Chouser: right

9:22 StartsWithK: hi

9:22 can someone explain what does this http://www.assembla.com/wiki/show/clojure/Getting_Tests_Into_Clojure mean

9:23 is clojure including test-is, templates and java-utis in core distribution?

9:24 rhickey: StartsWithK: we're working out how to get tests into clojure, seeing what would need to move over etc

9:24 trying to avoid template, actually

9:25 StartsWithK: and test-is? will that make it official clojure testing library?

9:25 rhickey: StartsWithK: not so much official, just the one Clojure uses to test itself

9:26 will not be called test-is

9:26 StartsWithK: if so, is it to late to ask that clj-unit could be used in consideration

9:26 rhickey: StartsWithK: you need to convince people to write their tests with it, test-is is being used by many in contrib

9:27 StartsWithK: and for java-utils, will it go full, or will thigs like with-system-properties, and as-file as-str be stripped from it

9:27 i think that with-system-properties even has a race condition

10:07 Chouser: StartsWithK: I think it's mostly about getting the clojure tests into the clojure project. Currently the clojure tests use test-is, so it has to come along too.

10:09 StartsWithK: Chouser: so, test framework dosn't need to be a part of clojure.jar distribution? something like that

10:22 Chouser: well, if it's included in the clojure repo, it would seem a shame to make it unavailable to users of the jar, don't you think?

10:25 StartsWithK: in such a situation it will become a official testing framework for clojure, and as such, i don't see it as a good option

10:26 official more by convinience than anything else

10:29 not saying that is a bad thing that clojure gets one, but it will affect a lot of people, so maybe evaluation of other testing frameworks shoud be done

10:30 Chouser: I guess my point is it's not a matter of evalutation, it's a matter of the actual clojure tests that have been written

10:30 160 tests containing 2953 assertions.

10:30 rhickey: StartsWithK: the tests for clojure are written in test-is, there's nothing to evaluate bout that. This isn't a declaration of merit as much as a recognition of use (not that it doesn't have merit)

10:32 StartsWithK: rhickey: i get that, but if included in core, and with current lack of infrastructure for package and distribute clojure libraries to other users, using test-is derivative in core will be the first choice for many

10:33 rhickey: StartsWithK: true

10:33 StartsWithK: (package and distribuate in automated way)

10:33 rhickey: but making clojure dependent on some other package has its own problems

10:33 StartsWithK: that is the catch 22 for both sides

10:34 rhickey: clojure's lack of deps has served it well, IMO

10:34 StartsWithK: only if you think there is harm to test-is, I don't

10:35 StartsWithK: rhickey: compared to clj-unit that uses only functions and one macro (for exception handling), test-is has magic symbols (_1 _2) and requires a full tree walker to execute its tests

10:36 rhickey: StartsWithK: that part of test-is is being reconsidered right now

10:36 StartsWithK: there was even a talk about 'compatibility' layer so it can be used with some other contrib library

10:36 Chouser: rhickey: is there any chance Gashinsky's first name has a typo on http://clojure.org/contributing

10:37 StartsWithK: rhickey: thats good to hear

10:37 rhickey: Chouser: yup

10:37 will fix

10:38 Chouser: thanks

10:39 bpattison: I'm looking for a function that applies a fn to every item in a list -- I know its clojure core somewhere -- any anyone help me out

10:41 Chouser: bpattison: 'map'?

10:42 ,(map #(* % %) (range 10))

10:42 clojurebot: (0 1 4 9 16 25 36 49 64 81)

10:43 bpattison: I tried that once, but I try it again -- I must have confused myself

10:43 thanks!

10:43 Chouser: sure! So you haven't given up entirely on clojure yet?

10:44 bpattison: oh. no. clojure's great! -- I just can't find the time to work on it -- but my little parser project is sputtering along

10:50 any fustration comes from thinking in OO where data comes first, then find the function to work on the data -- so its easy to say find methods that work on strings or files, or whatever -- where in clojure your looking for functions that match a algorithmic pattern -- so 1) its harder to conceptualize and 2) its harder to find functions that already exists because you can't base your searches on "strings", "file", etc.

10:56 blbrown_win2: general question. map is call to a sequence and returns a new sequence. What is a function like haskells _Map. Where you iterate over a sequence but DONT return the sequence

10:57 Chouser: blbrown_win2: for side effects? or what is returned?

11:03 blbrown_win2: anyway, you might want 'doseq'

11:16 blbrown_win2: Chouser, I was looking at trying to speed up some code, thought a map variant might help. I have another question. I know we should use (SomeClass. or .someMethod) but with the older form (. someMethod sdfs) is the call to '.' an actually function?

11:17 I wonder if I should get rid of that call to '.'

11:31 dreish: blbrown_win2: (.method o) is converted to (. o method) at macro expansion time.

11:31 ,(macroexpand '(.method o))

11:31 clojurebot: (. o method)

11:32 bpattison: I have (map str '(a b c)) --> ("a", "b", "c") -- but I want to get it to ("abc") -- any ideas?

11:32 dreish: apply str

11:32 bpattison: perfect -- thanks

11:33 dreish: reduce str if the seq might get long.

12:16 lenst: why is length an issue?

12:22 mattrepl: think it has to do with maximum arity of Java methods

12:27 lenst: ,(apply + (range 1 1000000))

12:27 clojurebot: 499999500000

12:27 lenst: is there such a limit?

12:28 mattrepl: thought there was to Methods

12:31 interesting, looks like I was mistaken

12:31 lenst: ,(apply (fn [& xs] (if (and (seq xs) (< (first xs) 1000)) (recur (rest xs)) 17)) (iterate inc 0))

12:31 clojurebot: 17

12:32 mattrepl: looking at AFn, it just converts the extra args to an array

12:35 lenst: RestFn is also interesting

12:38 Chouser: dreish: actually, apply str is better regardless of the length of the string.

12:39 dreish: Why is that? I wasn't watching this window, but my reason was that apply holds the head, and reduce doesn't.

12:39 Chouser: there's a limit on the number of individual args to a fn, but no limit on the size of the 'rest args' seq

12:40 dreish: Why is that an advantage for apply? Seems like that would be equivalent.

12:40 mattrepl: right, which is 21, including the rest seq that gets converted to an array

12:40 Chouser: dreish: hm, that's an interesting point.

12:41 mattrepl: was that number arbitrary?

12:41 Chouser: well, I don't think it's always convert to an array

12:42 mattrepl: well it's defined using varargs (i.e., type is Object...)

12:44 lenst: look at RestFn not AFn

12:45 ,(parents (class (fn [& xs])))

12:45 clojurebot: #{clojure.lang.RestFn}

12:47 Chouser: ,(parents (class (fn [x])))

12:47 clojurebot: #{clojure.lang.AFunction}

12:49 rhickey: chunked range rocks!

12:50 mattrepl: so for RestFn, the last argument could be the rest of the seq, not necessarily an array, but eventually it's converted to an array when IFn#invoke is called

12:51 dreish: rhickey: Is it in the master branch?

12:51 rhickey: dreish: not yet

12:51 will push to chunks branch in a seq

12:51 lenst: mattrepl: don't think so, last arg will be the rest sequence. See applyTo method in RestFn

12:54 Chouser: heh. in a "sec"?

12:55 the rest arg can be infinite.

12:55 mattrepl: lenst: that calls doInvoke, which I would imagine calls IFn#invoke, but I suppose it doesn't have to

12:55 dmos: ah, just checking, what is the current state of maven2 for building clojure? The pom at http://github.com/richhickey/clojure seems to be not functional (including the generated version), and also differs slightly from the last committed on trunk in svn...

12:57 lenst: mattrepl: that would be bad because RestFn.invoke calls doInvoke

12:57 Chouser: ,(take 20 (apply (fn [& xs] (filter even? xs)) (iterate inc 0)))

12:57 clojurebot: (0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38)

12:57 Chouser: so that's a fn that just took an infinite number of args and returned a lazy seq.

12:57 returned an infinite lazy seq.

12:57 dreish: Impossible! Magic!

12:58 Chouser: I know, fantastic, isn't it?

12:58 cp2: this _must_ be the work of the devil

12:58 dreish: (apply + (range 1000000)) is usually one of the first things I show people.

12:59 Chouser: rhickey: are you actively seeking help on the checked seq fns?

12:59 dreish: They think it's going to crash the repl, and it comes back with the answer in a fraction of a second.

12:59 Chouser: iterate could be chunked, I would think.

13:00 mattrepl: great, now I'm going to have to examine bytecode to be satisfied... =)

13:04 rhickey: Chouser: I am now, just wanted to do the basics - map/reduce/filter/range myself to sanity check the ideas. all pushed to chunks branch now

13:06 everyone please try the chunks branch when you have time on your own code - I want to make sure the chunked versions are fully compatible with existing code - so far I haven't touched any client code, just swapped out chunked versions under the hood - quite thrilling

13:06 * dmos wonders if anyone is using maven2 with clojure

13:07 dnolen: dmos: some people are it seems.

13:08 dmos: Mmh, but clojure itself is not buildable with maven, is it?

13:10 quidnunc: Anybody have an example of using zip-select in enlive?

13:29 jtal: is there a way to walk through a large file without a loop?

13:30 drewr: jtal: map/filter over line-seq? Depends on what kind of data is in there.

13:30 jtal: just plain text but very large

13:31 will map use the same piece of memory for each iteration?

13:32 that is, for each line

13:32 dreish: Why would that matter?

13:32 drewr: jtal: It won't retain the head of the seq, if that's what you mean.

13:32 jtal: memory used wont grow right?

13:32 drewr: Right.

13:33 jtal: and the whole file doesnt have to go into memory initally?

13:33 dreish: jtal: The GC will clean up as you progress through the file.

13:33 jtal: awesome

13:34 I'm using java.io.BufferedReader btw just in case thats not the cool thing to use :>

13:34 clojurebot:

13:34 jtal: <-- new to java and clojure

13:34 Chouser: jtal: sounds right

13:34 dreish: Isn't there something like (line-seq (reader filename))?

13:35 jtal: ah you're right

13:35 Chouser: there's clojure.contrib.duck-streams/reader

13:35 dreish: Thanks I just shut down my emacs in preparation for a reboot, or I'd have checked.

13:36 I wrote an auto-closing line-seq, but I can't remember where I put it.

13:37 I think it's at the office.

13:38 Chouser: duck-stream/read-lines does that

13:38 jtal: are you guys using lojure at work?

13:38 c

13:38 dreish: I have, a little.

13:39 quidnunc: ,seen cgrand

13:39 clojurebot: java.lang.Exception: Unable to resolve symbol: seen in this context

13:40 quidnunc: ,last cgrand

13:40 clojurebot: #<core$last__3771 clojure.core$last__3771@1509f8b>

13:40 dreish: clojurebot: seen cgrand

13:40 clojurebot: cgrand was last seen quiting IRC, 226 minutes ago

13:40 Chouser: ~seen cgrand

13:40 clojurebot: cgrand was last seen quiting IRC, 227 minutes ago

16:50 slashus2: I was playing with the new chunked seqs branch. I was excited to test the performance of it, but it seems something like (reduce + (range 1000000)) is a lot slower.

17:09 I think it is range that has slowed down on the sequence generation.

17:20 I guess there is a lot more going on inside of range now.

18:30 blbrown_win2: gnuvince_, hey, I liked your clojure performance article

18:30 Ive been using it all weekend diagnosis problems

18:31 gnuvince_: blbrown_win2: thanks; just some things I found out and decided to write.

18:37 Jetien: Hi can somebody tell me the difference between the two calls "java -cp #jars clojure.lang.Script #script" and "java -cp #jars clojure.lang.Script #script --"? The first one doesn't one doesn't show JFrame calls, but the second does.

18:38 hiredman: -- tells java to stop expecting arguments?

18:39 I am not sure if that is correct though

18:39 also, use clojure.main instead of clojure.lang.Script

18:39 Jetien: yes, but since there are no arguments after -- what difference does it make?

18:40 ok

18:41 hiredman: what is the context?

18:41 Jetien: I'm trying to run http://java.ociweb.com/mark/programming/ClojureSnake.html and one call succeeds and the other doesn't

18:42 hiredman: so you are using a shell script launcher thing?

18:42 Jetien: yes

18:42 hiredman: well, pastbin that

18:42 lisppaste8: url?

18:42 lisppaste8: To use the lisppaste bot, visit http://paste.lisp.org/new/clojure and enter your paste.

18:43 hiredman: as far as I know there is no official shell script launcher

18:43 lisppaste8: Jetien pasted "clj script" at http://paste.lisp.org/display/82197

18:44 hiredman: ah, well, there you go $*

18:44 Jetien: ok, i need to clarify

18:44 i was entering the commands manually in the console without the $*

18:44 hiredman: oh

18:45 ick

18:45 Jetien: the reason i'm trying to find out why the version with "--" works and the other doesn't is this:

18:45 hiredman: scriptname=$1 then $* is a bad idea

18:45 Jetien: "doesn't" means you get some kind of exception, or what?

18:46 Jetien: no it just runs silently

18:46 no swing gui is opened at all

18:46 hiredman: uh

18:46 Jetien: im using vimclojure and there's the same problem, that's why i'm trying to figure this out

18:47 hiredman: vimclojure is odd, I would not trust it to indicate a problem

18:47 as in, any issues you have while using vimcloure are just as likely to be vimclojure's as they are something else's

18:48 Jetien: but the behaviour is the very same

18:48 i call (com.ociweb.snake/main) - no errors, but silent

18:48 hiredman: 2 + 3 = 5 and so does 1 + 4

18:49 (if *command-line-args* (main))

18:49 Jetien: yes i admit you're right but it's a possibility

18:49 hiredman: at the bottom of the snake code

18:49 Jetien: yes, that's why i start main manually

18:49 arbscht: *command-line-args* is (--) when you pass --

18:50 hiredman: Jetien: ok, so, to start clojure, what exactly are you typing?

18:51 Jetien: um..that's strange...it's working now - not in vimclojure though

18:52 i guess it was the *command-line-args* guard after all

18:52 but this still doesn't explain why it's not working in the repl of vimclojure

20:30 krumholt_: what is the equivalent to funcall in clojure?

20:31 slashus2: I don't think you need it.

20:31 Raynes: What is funcall? >_>

20:32 krumholt_: (def a (fn [] (+ 3 4)) now i want to call the function in a

20:32 Anniepoo: (a)

20:32 ??

20:32 Raynes: ^

20:33 krumholt_: yes (a). ok another example. (defn foo () "bar") (def a 'foo)

20:34 Raynes: I think you mean (defn foo [] "bar")?

20:34 krumholt_: yes

20:34 sry

20:34 slashus2: Why did you quote the foo before you assigned it to a?

20:35 Raynes: (def a (foo))

20:35 slashus2: Raynes: I think he wants to assign foo to a, not the result of it.

20:35 Chouser: or (def a foo) depending on what you mean

20:35 cemerick: krumholt_: there is no funcall -- there's apply. Clojure is a lisp-1.

20:35 krumholt_: ok i got it thanks

20:35 so i cannot assign a value and a function to a symbol

20:36 Chouser: well, you can't assign to a "symbol" anyway, but what you mean is correct

20:36 krumholt_: yes bind

20:36 ok thanks

20:36 Chouser: there are not separate namespaces for values vs. functions.

20:36 bpattison: (defmulti concat_fruit :kind)

20:36 (defmethod concat_fruit :apple [a b] (str a b "apple"))

20:36 (defmethod concat_fruit :oragne [a b] (str a b "orange"))

20:36 (concat_fruit {:kind :apple} "b")

20:36 "{:kind :apple}bapple"

20:36 (defmethod concat_fruit :lemon [a b c] (str a b c "lemon"))

20:36 (concat_fruit {:kind :lemon} "b" "c")

20:36 java.lang.IllegalArgumentException: Wrong number of args passed to keyword: :kind (NO_SOURCE_FILE:0)

20:36 Can anyone tell me why or how to work around multi-methods not accepting 3 arguments?

20:37 krumholt_: Chouser, ok thanks. i was used to that from cl and got confused.

20:37 thanks everyone

20:37 Chouser: bpattison: the problem is that your dispatch "function" :kind doesn't take 3 args.

20:38 bpattison: you want to dispatch on the :kind of the first arg?

20:38 bpattison: that's correct -- the first arg

20:38 Chouser: krumholt_: I was meant to be pedantic about your use of "symbol" not your use of "assign"

20:38 bpattison: so I need to define a dispatch function that takes 3 args?

20:39 Chouser: krumholt_: symbols in clojure do not hold values (or functions)

20:39 bpattison: yes. probably something like (defmulti concat_fruit (fn [a & args] (:kind a)))

20:39 bpattison: and next time please use paste

20:40 lisppaste8: url?

20:40 lisppaste8: To use the lisppaste bot, visit http://paste.lisp.org/new/clojure and enter your paste.

20:40 Anniepoo: can somebody explain 'state' as it's used in http://clojure.org/state

20:41 Chouser: krumholt_: I'm not sure exactly how CL works, but in Clojure a literal symbol in your code may refer to a local or to a Var. Those are what are bound to values.

20:41 bpattison: I will try

20:42 chouser -- that worked like a champ -- so how did it know how to handle 2 args?

20:43 Chouser: the "& args" part means take any number of remaining args and put them in a seq bound to "args"

20:43 krumholt_: Chouser, hm not exactly sure i get it. i will experiment a little more

20:43 clojurebot: Who??

20:44 Chouser: krumholt_: it's a pretty subtle point. it may not matter to you.

20:44 Anniepoo: "state" is any variable or object data member that hangs around getting its value changed from time to time

20:44 A

20:45 krumholt_: Chouser, i think i get it the symbol binds to a var. i can get the the var with #'foo

20:45 Anniepoo: ok

20:45 how is that not an identity?

20:45 Chouser: Anniepoo: for example the session values for a web app would be one kind of state

20:45 Anniepoo: ok

20:45 yes, I was thinking of the entries in an LDAP

20:46 as identities.

20:46 cemerick: krumholt_: I've long since forgotten the finer points of CL, but clojure's model is definitely simpler around symbols, etc. It'll click for you. Internalizing this is critical: http://clojure.org/vars

20:46 krumholt_: cemerick, thanks

20:47 Anniepoo: identity "the port we're listening on" - which is buried, assuming we're an app level programmer, in some library after we open the serversocket

20:48 so the :state entry in a :gen-class is a symbol bound to something that hangs around?

20:48 on a per object level?

20:48 Chouser: Anniepoo: yes

20:48 Anniepoo: thanks., I get that

20:48 Chouser: but clojure is careful to make sure these identities control how their state changes

20:49 Anniepoo: now I'm confused what the exact syntax of :state is in :gen-class

20:49 Chouser: the simplest being an atom -- it only ever has one value. The only ways to change it require that they happen in order

20:50 Anniepoo: right. Hence the odd constructs like let

20:50 Chouser: this is how it's different from java, for example, where you could have a static class member foo with data members bar and baz. Threads go read, write, and generally mess around with bar and baz uncontrolled.

20:51 Anniepoo: right

20:51 Chouser: so you have a question about gen-class syntax?

20:51 Anniepoo: well, as I understand it in Clojure you can't mess around with bar and baz if they're not static either???

20:52 Chouser: well, if they're actually java data members, you can still do what you want :-P

20:52 Anniepoo: yah, suppose I have a simple case - I want to subclass some java class and attach some data to it

20:53 Chouser: but you wouldn't do that. you would make bar and baz be, say, refs: (def foo {:bar (ref 0), :baz (ref 0)})

20:53 Anniepoo: I want to make a JButton, when you click it it changes from whatever's in the text to "HI"

20:53 and when you click again it changes back - so I need to keep the old value

20:54 Chouser: a jbutton has a hold wad of state inside it.

20:54 quidnunc: cgrand: Is the definition of text-node correct? zip-pred tests z/branch? but that will be false for a string node I think.

20:54 Anniepoo: sure, of course

20:55 Chouser: Anniepoo: but yes, it would be sensible to try to ignore that and store your old value in a nice clean clojure reference object.

20:55 Anniepoo: yes

20:57 yah, my real example is too complex to ask about, so I'm making up an example

20:57 Chouser: :-)

20:57 Anniepoo: but just trying to understand how I glue some extra data to a java object when subclassing

20:58 in effect getting a member variable

20:58 Chouser: ah, yes.

20:58 do you need to add methods, or is proxy sufficient?

20:59 Anniepoo: I need to store additional state

20:59 I'm making a clojure editor, the 'button' is a panel that maps to a clojure form, I need to attach it to the model

20:59 Chouser: yes, but you can do that via closures with proxy.

21:00 I mean, a proxy can close over additional state.

21:00 Anniepoo: ??

21:02 Chouser: (def obj (let [v (atom 0)] (proxy [Object] [] (toString [] (str (swap! v inc))))))

21:03 that creates a proxy that closes over v, and stores the proxy object in obj

21:03 samuels: Chouser: dont you think that let should just be replaced by let* (and called simply 'let') so that it's easier for noobs

21:04 Chouser: now each time you call (.toString obj) or just print it at the repl, it'll inc v and return a string with the new value of that state

21:04 samuels: already is.

21:04 samuels: really?

21:04 ah ok, i just remember seeing a let* in the 'programming clojure' book

21:04 Anniepoo: far out!

21:07 that's why the (atom 0)

21:08 this language will either save my soul or damn me to heck

21:08 darn me to heck?

21:11 thanks!- I'll go stick head back in clojure book

21:13 Chouser: Anniepoo: right. without atom you could still close over a value, but you couldn't change it.

21:17 Anniepoo: I keep wanting my OOP.

21:17 Chouser: Anniepoo: you'll get over it. :-)

21:19 well, I'm still working to get there. the more stateful the task at hand, the harder I'm pulled toward OO concepts.

21:19 Anniepoo: I feel like I'm a novice in a religious order... yes teacher, I will get used to sleeping on the floor and eating only a handful of rice each day

21:20 isn't it appropriate to have OO concepts some times?

21:20 suppose you're doing something that would be well handled in an OOP language

21:21 a game with pieces with varying capabilities perhaps

21:21 Chouser: yes

21:21 have you looked at multimethods?

21:22 Anniepoo: I've been programming since before OOP came along, so it's not totally foreign

21:22 don't multimethods end up distributing the code that handles a class all over?

21:22 I mean, I remember structured programmers resistant to OOP who would put case statements everywhere

21:23 Chouser: you can distribute the code however you want -- group the methods by dispatch object or by method, your choice.

21:24 Anniepoo: ah, cool, I didn't know that

21:24 krumholt_: can i change a var in a let form? i want to do (let [a 1] (???set??? a 2)(print a))

21:26 Chouser: krumholt_: vars generally should only be changed within a thread-local binding. Is that what you want?

21:26 krumholt_: yes

21:26 Chouser: oh, wait.

21:26 that's not a var

21:26 slashus2: You can't do that with a local.

21:27 Chouser: what slashus2 said.

21:27 slashus2: You can create an atom or a ref and change them sort of.

21:27 Chouser: krumholt_: you can do (let [a 1, a 2] (print a))

21:27 slashus2: (let [a (atom 1)] (reset! a 2))

21:28 krumholt_: slashus2, that seems to be what i want

21:28 Chouser: krumholt_: we probably need to know more about what you're really trying to do.

21:28 Anniepoo: (let [a (atom 1)] (swap! a 2) (print a)) Is that what he's trying to do? Or am I bogus?

21:29 krumholt_: something like: (let [counter 0] (defn inccount [] (incf counter)) (defn show [] counter))

21:29 Chouser: it's rarely necessary or idiomatic to use an atom or other reference type within a purely local scope.

21:30 Anniepoo: (let [a 1] (let [b (inc a)] (print b))) is that the idiomatic way?

21:31 Chouser: Anniepoo: sure, that's better than using atom.

21:31 Anniepoo: (let [a 1] ...bunch of stuff...(let [b (inc a)] ... bunch more stuff... (print b)))

21:35 krumholt_: ok thanks. it is not exactly what i want, but than again i shouldn't be doing that anyway. i am just trying to get a feeling of what i can and cant do with clojure

21:46 Anniepoo: (let [a (atom 1)] (swap! a 2) (print @a)) did I need this?

21:46 (@ sign)

21:47 gnuvince_: Anniepoo: @x is syntax for (deref x)

21:47 Anniepoo: yes

21:48 but I have to deref here?

21:48 gnuvince_: so x is the ref and @x is the actual value, so you need the @a depending on what you want to display

21:48 slashus2: For atoms and refs, yes.

22:12 Anniepoo: is there a way to ifdef out code in Clojure?

22:13 I'm in the frustrating noobie situation that I changed a working program and broke it, now I can't get back to where I was

22:13 duck1123: there's if

22:13 Anniepoo: kk

22:13 duck1123: what exactly are you wanting to do?

22:16 Chouser: you can "comment out" a s-expr using #_

22:16 Anniepoo: thanks

22:16 Chouser: ,(+ 4 #_ (garbage i don't want) 5)

22:16 clojurebot: 9

22:17 duck1123: Chouser: I didn't know about that one. does that remove it completely, or return nil

22:18 I've run into issues with (comment) changing my return value

22:19 ,(do 1 #_ (+ 1 1))

22:19 clojurebot: 1

22:19 * duck1123 makes a mental note

22:21 Chouser: duck1123: right, removes it at read time. Does not insert (or return) nil.

22:21 slashus2: #| |# will come later?

22:22 Chouser: what is that? block comment?

22:22 slashus2: That removes it at read time.

22:23 Chouser: dunno.

22:23 should it nest?

22:24 duck1123: I still say that XQuery has the friendliest commenting system

22:24 (: this is a comment :)

22:24 arbscht: ha

22:26 Anniepoo: strange. I've got a window that was working fine. I messed with the stuff I asked about earlier, tried runnign it, and the window gets no repaint event

22:26 breaking in with the debugger always stops with, of all things, somewhere in file input operations

22:28 slashus2: Anniepoo paste it in http://paste.lisp.org/

22:28 Anniepoo: kk

22:29 lisppaste8: /url?

22:29 lisppaste8: To use the lisppaste bot, visit http://paste.lisp.org/new/clojure and enter your paste.

22:30 Anniepoo pasted "wont redraw" at http://paste.lisp.org/display/82208

22:30 Anniepoo: sorry to ask for help with what should be a simple case of going back to what I had before

22:33 duck1123: odd that you're not using the ns macro

22:34 Anniepoo: I'm a total noob

22:34 I'm lucky I haven't shot myself with this thing yet

22:34 Chouser: what's the problem?

22:34 I get a window with 2 sets of 3 labels

22:35 Anniepoo: mouse over it

22:35 sometimes it redraws, sometimes not

22:35 sometimes it comes up, draws the frame, never draws the content area

22:36 swing threading weirdness?

22:36 hard to believe - It worked consistently before

22:36 Chouser: maybe need to flush stdout?

22:36 Anniepoo: I've noticed that print doesn't give me output, just println

22:37 wonder why it started this

22:37 Chouser: print doesn't flush the output

22:37 dunno why you wouldn't have had that problem before.

22:38 Anniepoo: because every mouse action must end with an up and that's println

22:38 Chouser: if I sprinkle in (flush) after every (print ...) I seem to get good output

22:38 Anniepoo: kk

22:41 strange

22:41 I did that, didn't help

22:41 lisppaste8: url?

22:41 lisppaste8: To use the lisppaste bot, visit http://paste.lisp.org/new/clojure and enter your paste.

22:42 Anniepoo annotated #82208 "untitled" at http://paste.lisp.org/display/82208#1

22:42 Anniepoo: ok, there's my version

22:42 I tried restarting my ide

22:43 Chouser: I guess I'm not quite sure what you're wanting.

22:43 Anniepoo: I'd like the window to repaint and not hang

22:43 it's not reliably repainting on my system

22:44 lisppaste8: Chouser annotated #82208 "my flushes" at http://paste.lisp.org/display/82208#2

22:44 Chouser: I don't know what you mean by "repaint" you're expecting the boxes to draw differently somehow?

22:45 Anniepoo: I'm expecting them to draw

22:45 I see the corner of my IDE inside, on about 50% of the runs

22:46 on the other 50% I get the initial draw

22:46 but then when I move the mouse over the windo it gives me a wait cursor

22:46 Chouser: I can resize and move around the window and it still looks good.

22:46 Anniepoo: and nothing else happens

22:46 !!!!

22:47 can you move your mouse over the windo? It should print some commas and []

22:47 I never get that output

22:47 Chouser: yes, I get commas and []

22:48 and dots

22:48 Anniepoo: what's your ide?

22:48 Anniepoo: IntelliJ

22:48 yah, it's working for you

22:48 hmm... I think I installed the old CloJet at one point and borked my install somehow

22:49 I get an ide error complaining that it's already got a language called Clojure

22:49 but the odd part is, I didn't mess with the IDE at all

22:49 I was working fine

22:49 asked you the question earlier

22:49 about how to keep state

22:50 added a toy demo of it and tried to run, It did this

22:50 Chouser: java -cp clojure.jar:clojure-contrib.jar clojure.main -i yourcode.clj

22:50 that's how I'm running it.

22:50 Anniepoo: let me try it from the cmd line

23:00 lisppaste8: Anniepoo annotated #82208 "untitled" at http://paste.lisp.org/display/82208#3

23:00 Anniepoo: yah, I always get this when I start intellij

23:02 ok, I'm going to do a hard reboot

23:18 ok, that's maximally strange

23:18 I rebooted the machine and that fixed it

23:22 Chouser: wow

23:22 yummy

23:24 Anniepoo: there's a race condition between two plugins apparently

23:25 Chouser: nice

23:25 well, glad you found a way forward. Sorry it was a random bug absorbing your time :-/

23:25 Anniepoo: what's the status of clo-jet?

23:25 Chouser: I'm off to bed.

23:26 Anniepoo: yah, sorry to take your time with this noob stuff

23:26 I appreciate it

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