08:41 <flux> at times it has been said that some aspects of type classes would be possible to emulate with classes

08:42 <flux> for example the Num-class would be possible that way: val (+) : 'a num -> 'a num -> 'a num, right?

08:42 <flux> I wonder if anyone's tried to write a monadic library that way

08:43 <flux> the problem with the num-class would be that for example numbers would need to be lifted into the monad manually

08:43 <flux> but I wonder if the problem persists when writing the bind-function for a monad

12:43 <yziquel> hi. i've been trying to do a Thread.select, and I end up with the following error message:

12:43 <yziquel> Thread 3 killed on uncaught exception Unix.Unix_error(3, "select", "")

12:43 <yziquel> Anyone knows what error code 3 stands for in select?

12:45 <gildor> yziquel: Use Unix.handle_unix_error around your Thread.select

12:46 <yziquel> gildor: looking at this function...

12:48 <yziquel> hum. handle_unix_error is not very convenient with many arguments... i'll put that in my code right away.

12:54 <yziquel> gildor. Thanks. It complains about a bad file descriptor... even though I do not know why. Thanks.

12:54 <gildor> windows or linux ?

13:01 <yziquel> gildor: linux.

13:02 <gildor> yziquel: maybe already closed file descriptor ,

13:02 <gildor> ?

13:03 <yziquel> gildor: that's possible.

13:11 <yziquel> gildor: what happens if i'm waiting in a Thread.select and, meanwhile, i close one of the file descriptors it's waiting on? Will it continue to wait for some event on another file descriptor, or just raise an error?

13:15 <gildor> yziquel: I think it will raise an error

13:17 <yziquel> gildor: hmm. Painful. Lots of mutexes to use, then... thanks.

13:59 <Yoric[DT]> yziquel: unless I'm mistaken, OCamlNet's equeue has a much more friendly interface than Unix.select.

15:39 <yziquel> Yoric[DT]: thanks. I'll have a look at it at some point.

15:40 <Yoric[DT]> The site seems down at the moment, though.

15:56 <yziquel> i've got another issue (will look at equeue later on): I'd like thread 1 to wait for thread 1 to get in the Thread.select statement. I want thread 1 to resume activity only when I'm sure that thread 2 is listening. Anyone has suggestions on how to do that?

15:56 <yziquel> Sorry: I'd like thread 1 to wait for thread 2 (not 1).

16:02 <Yoric[DT]> Well, you can try playing with Condition and Event.

16:21 <yziquel> Yoric[DT]: As far as I understand these two modules, they are not satisfying: The condition that I need is "waiting in Thread.select"... Can't trigger it before being in Thread.select (race condition), and can't trigger after Thread.select, 'cause I'd be waiting in Thread.select for quite a long time... As for the Event library, the situation seems to be the same.

16:35 <yziquel> Sorry, had trouble with my computer. To sum up, what would be really great would be to have a Condition.select statement, doing the same thing as Thread.select, and sending a signal to the other threads waiting for that signal. Can this be done?

16:39 <Yoric[DT]> Sorry, I haven't toyed with select, so I'm not sure.

16:39 <Yoric[DT]> There's an Event.select, though, isn't it?

16:56 <flux> I suppose the Event-module can be used for most synchronizaton purposes

16:56 <flux> ..once you get the idea on how to use it :)

16:57 <flux> the first time I saw its interface it didn't quite dawn on me; I had to refer to concurent ml documentation to get it

17:29 <Yoric[DT]> I actually liked it when I saw it first.

17:29 <Yoric[DT]> I just haven't used it many times -- and never in conjunction with Unix.

17:30 <flux> it's difficult to interface anything non-file with Unix.select..

17:30 <flux> you basically need to have another thread with a pipe that feeds stuff to it

17:30 <flux> (or process)

17:31 <flux> I suppose it might be possible with signals and polling too, but using a pipe sounds more robust

18:44 <davidm123> is there a recommended way to build mingw binaries under a cygwin version of ocamlc?

18:44 <davidm123> I tried "ocamlc -custom -verbose -ccopt '-mno-cygwin' ...", but that tries to link to /usr/lib/ocaml/libcamlrun.a (a cygwin library)

18:58 <Yoric[DT]> Mmmhh....

18:58 <Yoric[DT]> I'm trying to compile a file foo_bar.ml as if it were module foo.ml .

18:58 <Yoric[DT]> Any idea?

18:59 <Yoric[DT]> (technically, I have a module which I want to compile both as a Mylibrary.cma and Mylibrary_nothreads.cma)

19:01 <Yoric[DT]> My explanations are unclear.

19:01 <Yoric[DT]> Let me restart.

19:01 <Yoric[DT]> I have two modules, one defined in a.ml and the other one defined in a_nothreads.ml .

19:02 <Yoric[DT]> I would like to compile them respectively to a.cma and a_nothreads.cma .

19:02 <Yoric[DT]> Now, they define the same interface, except one works when linked with -thread and the other one when not linked with -thread.

19:03 <Yoric[DT]> So I'd like both of them to define the same module A.

19:04 <Yoric[DT]> Of course, with a.ml and a_nothreads.ml, I'm going to end up rather with two distinct modules A and A_nothreads .

19:04 <Yoric[DT]> Which is not as nice.

19:04 <bacam> But for some reason you want to avoid a separate nothreads directory?

19:04 <Yoric[DT]> Any idea?

19:04 <Yoric[DT]> Well, I can't think of any way of having two fully separate directories with OCamlBuild.

19:04 <bacam> Ah, I've no experience of ocamlbuild.

19:05 <Yoric[DT]> Yeah, with a regular Makefile, it wouldn't be too hard.

19:05 <Yoric[DT]> Mmmhh... I may have an idea.

19:18 <Yoric[DT]> Ok, separate subdirectories are possible with ocamlbuild, after all.

19:28 <Yoric[DT]> Gasp.

19:28 <Yoric[DT]> Except something is bound to fail.

19:28 <Yoric[DT]> Mmmhh....

19:29 <Yoric[DT]> Well, I guess I'm going to make two distinct findlib packages, after all.

20:12 <palomer> :O>