7:14 hoeck: rhickey: thanks for fixing!!!
7:36 rhickey: you're welcome
9:16 MarkJP: what am I doing wrong: (ns-interns 'clojure)
9:17 rhickey: 'clojure is a symbol, ns- fns take namespaces: (ns-interns (find-ns 'clojure))
9:18 I hope to change most of these to take a ns 'designator', i.e. either the ns itself or its (symbol) name
9:18 in my spare time...
9:20 * bgeron sees the benefits of static typing here
9:21 bgeron: (because you could set up a rule on how to make a ns out of a symbol
9:22 rhickey: ew
9:22 bgeron: not nice?
9:22 rhickey: user-defined conversions ruin static typing
9:22 bgeron: depends on how it's implemented
9:22 rhickey: because you can;t control when they are used
9:23 * bgeron wants to try such static typing in a language: such a find-ns only gets namespaces, and the calling code automagically makes a ns out of the symbol (such converters are lexically scoped)
9:25 rhickey: not worth it - every feature like that adds more complexity than it reduces
9:26 see Scala
9:30 Chouser: bgeron: yeah, Scala has a complete set of features for auto-converting from types to other types.
9:31 * bgeron should really look into it then
9:31 rhickey: I meant more generally - see Scala for an example of exponential complexity of interacting features
9:31 bgeron: ah
9:33 la_mer: bgeron: we use Scala for a real product (which stuns people sometimes) -- it's definitely got a 45-piece Craftsman set of tools, but one often finds that the set is missing simple screwdrivers, etc.
9:33 when its features map well to your problem, it's *very* nice, though
9:33 bgeron: but then I also think that CL's &optional shouldn't have been hardcoded
9:33 then maybe its features are too hardcoded :)
9:34 PG's (opt x) syntax looks nice
9:36 rhickey: (opt x) ?
9:36 * bgeron wants to have 50 hours in a day, so bgeron has time for such things
9:36 la_mer: this is arc, yes?
9:36 bgeron: (fn (a b (opt c)) ..)
9:36 no, it was a plan for arc
9:36 well, maybe it is real arc
9:36 * la_mer rolls his eyes in the general direction of arc :-)
9:36 bgeron: but if it's real arc, it's probably hardcoded :(
9:37 down? ;)
9:37 la_mer: I hadn't thought that far.
9:37 Chouser: I think arc has optional args without using an "opt" keyword.
9:37 * bgeron looks it up
9:38 Chouser: ...And I think I prefer clojure's mechanism for different arities on the same function.
9:38 * la_mer nods
9:39 bgeron: what's the difference?
9:40 (not meaning to imply "there is no difference")
9:40 Chouser: The difference in how clojure does it?
9:40 bgeron: yes
9:41 Chouser: I think boot.clj's "reduce" function is a good example.
9:41 It takes 2 or 3 args: either [f coll] or [f val coll]
9:41 bgeron: blegh, arc does optional args with (o arg [default])
9:41 rhickey: fyi Clojure used to have full CL &optional &keys and &rest
9:42 bgeron: casing on different lengths is nice :)
9:42 rhickey: and each fn was a single entry point, which dealt with that stuff
9:43 la_mer: rhickey: that was dropped to align more closely with java's function call mechanics, yes?
9:43 rhickey: now each entry point is distinct - IFn has 20+ overloads
9:44 doing it this way is very much faster - esp when & comes into play
9:44 Chouser: I've started peeking at the Clojure Java code. I'm so glad rhickey wrote that kind of painful code so I don't have to. ;-)
9:44 rhickey: compare to other JVM langs which pack args into Object
9:44 Clojure uses real stack
9:46 Chouser's example is good too, real overloading is not the same as optional
9:47 Chouser: I must admit I have to beat down an occasional yearning for type-based overloading.
9:47 rhickey: multimethods
9:48 Chouser: oh!
9:48 hm, how did I forget about those.
10:05 * bgeron hates himself
10:06 Chouser: aww... why's that?
10:06 * bgeron has two health insurances for the rest of this year
10:06 bgeron: pretty pricey
10:06 Chouser: I bet.
10:07 bgeron: and I'm supposed to become the treasurer of an association this evening :p
10:07 (because if there would be no new board, the association would get disbanded)
10:08 maybe secretary would have been a better position for me
12:07 nsinghal: (def aa (fn  :ns))
12:07 (aa) returns :ns
12:07 (def bb #(:ns))
12:07 (bb) throws Arity error
12:09 rhickey: #(...) => (fn [args] (...)) so #(:ns) => (fn  (:ns))
12:09 nsinghal: (def cc #(:ns %))
12:10 rhickey: in the latest version error would be:
12:10 java.lang.IllegalArgumentException: Wrong number of args passed to keyword: :ns
12:11 nsinghal: thanks that explains it
12:13 Chouser: rhickey: great update to the error message, by the way. Bound to be helpful.
12:14 rhickey: :)
12:26 Chouser: what do you think of: (defn coll? [x] (or (seq? x) (vector? x) (map? x) (set? x)))
12:27 rhickey: (instance? IPersistentCollection x)
12:29 Chouser: hm! Well, I can't be sure, but I suspect that when people are asking for something that says if an object is "seq-able" (and you rightly point out that (seq "foo") works and isn't what they want) ... what they may really want is coll?
12:30 rhickey: sometimes - that fact that it includes maps may not be what they intend - There's also Sequential
12:31 but I can add predicates for all the marker interfaces
12:31 IPersistentCollection, Sequential, Reversible, Associative etc
12:32 Chouser: you may be right -- it's hard to tell. Most place where I'm doing something like seq? I mainly want to know if I should recurse into it or not. So true for maps and other collections, false for strings, keywords, symbols.
12:32 Are those names currently documented anywhere?
12:32 Docs may be sufficient, and then you don't have to clutter up the clojure namespace with a bunch of new predicates.
12:33 rhickey: unfortunately I still haven't gotten around to documenting the Java side - which is quite extensive
12:33 Chouser: ok
12:43 MarkJP: what is the equivalent of instanceof in clojure
12:44 Chouser: instance
12:44 MarkJP: thx
12:44 Chouser: (instance? Classname obj)
12:44 sorry, I forgot the question mark
12:44 MarkJP: cool
12:46 so lets say I proxy class Foo
12:47 (proxy [Foo]  (method1  ... ) (method2 ...))
12:48 the resultant object doesnt seem to pass the (instance? Foo o) test
12:49 actually sorry, Foo is an interface in this case
12:50 Chouser: Well, you've just surpassed my knowledge. :-/ sorry.
12:52 MarkJP: np, I'll wait for Rich, he seems to know Clojure pretty well
12:54 interesting, it passes the instance? test for another proxy i did
12:54 I'm doing something wrong
13:00 rhickey: proxy should pass instance? for all of its supers
13:01 MarkJP: oh man
13:01 it works now
13:01 rhickey: gremlins
13:02 MarkJP: wow... don't do this:
13:02 (import '(clojure.lang.RT) '(clojure.lang.Var)) in clojure
13:02 proxy wasnt working
13:03 I was able to make up methods within proxy without complaint
13:04 those imports where not intentional, cut and paste from java code
13:06 that's a quick pass. probably a little buggy.
13:06 not to mention ugly.
13:06 MarkJP: cool, how did you generate that?
13:07 Chouser: heh. well...
13:09 MarkJP: cool
13:09 Chouser: I think the word you're looking for is "gross", but I'll take "cool". ;-)
13:11 MarkJP: nah, definitely a neat one liner
13:34 rhickey: Chouser: wow - what a fun graph!
13:35 have to put it up on my wall so I can remember my design :)
13:40 missing a few things, though
14:18 Chouser: oh, is it? well, I think a hand-created one will look better anyway.
14:18 What's missing?
14:19 rhickey: IPersistentVector extends Associative, Sequential, IPersistentStack, Reversible
14:20 IPersistentMap extends Iterable, Associative
14:20 etc, all like that
14:21 the nice thing about a generated one is you don't have to maintain it
14:21 just regen
14:22 Chouser: yeah, but it's ugly.
14:22 I have long wished for some tool that combines the best of both, but I don't know of any such beast.
14:23 rhickey: as long as you can follow the paths, it has great utility even if not beautiful
14:23 Chouser: Like have a script generate SVG. Then edit the SVG in inkscape. Then have the script read new graph data *and* the SVG and make minimal changes to update any edges and nodes that have changed
14:24 hm. Well, maybe I'll try to refine the autogen process a bit then.
14:24 dot can be a little prettier, I think.
14:24 rhickey: I have OmniGraffle - if you can get it into a form it can import, it can make it pretty
14:25 Chouser: I've not seen OmniGraffle. Looks pretty. The front page says it has Graphviz built in... and it import dot scripts?
14:25 er, "can it import"...?
14:26 rhickey: got me, looking now
14:26 says a subset
14:27 Chouser: hm.
16:05 MarkJP: how do I do (new Foo.SubFoo ...)
16:06 rhickey: nested classes are separated by $ from their parents (a JVM thing): Foo$SubFoo
16:07 MarkJP: thx
16:20 Chouser: any easy way to convert a String to a java byte array?
16:21 rhickey: (. s (getBytes))
16:21 Chouser: oh. :-) right, thanks.
16:47 this works: (new javax.swing.ImageIcon "/tmp/tmp.png")
16:47 this doesn't: (new javax.swing.ImageIcon (. (slurp "/tmp/tmp.png") (getBytes)))
16:48 An ImageIcon object is created, but it doesn't display anything.
17:00 (int (first (slurp "/tmp/tmp.png"))) ==> 65533 ...but how could the first byte be larger than 255?
17:05 hoeck: unicode?
17:06 (slurp ) returns a string
17:08 Chouser: yeah. I thought of that, but that doesn't seem to be it.
17:09 well, it's not 2-byte unicode. Maybe it thinks it's utf-8 or something.
17:12 UTF8 it is.
17:14 drat. forcing US-ASCII isn't helping.
17:15 Oh, that's 7-bit. ISO-8859-1 does it.
17:23 hoeck: maybe it needs the magic number from the beginning of the image be stripped off?
17:24 or the actual image-data begins at an certain offset in the image file
17:27 Chouser: no, you were right. It was just unicode.
17:27 hoeck: oh, ok
17:28 Chouser: If I create the InputStreamReader with ISO-8859-1, and write the bytes into ByteArrayOutputStream, I can do toByteArray and the icon works fine.
17:31 hoeck: mhh, i'm wondering wether one could directly read data from /dev/video using this method