Here is the latest Caml Weekly News, for the week of 08 to 15 November, 2005.
Archive: http://thread.gmane.org/gmane.comp.lang.caml.general/31116Continuing the thread from last week, Richard Jones said:
And yet another way is to use perl4caml and WWW::Mechanize which is wrapped by perl4caml. This allows you to fairly easily navigate websites (click links, push buttons, fill in forms and so on). Rich.  http://merjis.com/developers/perl4caml/  http://search.cpan.org/dist/WWW-Mechanize/lib/WWW/Mechanize.pm
Archive: http://thread.gmane.org/gmane.comp.lang.caml.general/31123Following last week's announcement by Markus Mottl, Owen Gunden said:
> we'd like to announce the availability of "Sexplib" There is now a godi package: godi-sexplib
Archive: http://thread.gmane.org/gmane.comp.lang.caml.general/31022Continuing last week's thread, Jonathan Bryant asked and Richard Jones said:
> First of all, what is going on in the Event module? I can't exactly get > it to work an I fear I'm missing some important concept. I can't find > any documentation other than the interface. Does anybody know of any > further documeeentation or have a good explanation of exactly what's > going on. Yes, the Event module is quite confusing. I have used it in this code (in the file adwords_mt.ml) to implement a simple command pipe between a parent thread and worker threads, so you might want to download and take a look at this code: http://merjis.com/developers/adwords_api http://merjis.com/_file/adwords-api-1.0.6.tar.gzGrégory Guyomarc'h also answered:
I found these two references useful to understand the Event library: CML: A higher-order concurrent language John H. Reppy, In ACM SGPLAN '91 Conference on Programming Language Design and Implementation, pages 293-305. ACM Press, 1991. http://portal.acm.org/ft_gateway.cfm?id=113470&type=pdf Higher-order Concurrency John H. Reppy, Computer Science Technical Report 92-1285, Cornell University, June 1992. http://people.cs.uchicago.edu/~jhr/papers/1992/phd-thesis.html I think there is also a short example on how to use this module in OCaml Oreilly book.
Archive: http://thread.gmane.org/gmane.comp.lang.caml.general/31196Florian Weimer asked and Damien Doligez answered:
> I've got to different types of objects, say database tables and > cursors for one table. Caml code is expected to access these objects > using some handle reference. > > > * If the GC detects that no handles for a particular cursor exist > anymore, the underlying cursor object should be closed (which may > free external resources such as locks). At this time, all "equal" > handles become invalid, subsequent operations will fail. > > * If the GC detects that no handles for some table object exist, and > there are no handles for that table, this table is closed. > Subsequent operations on "equal" table handles will fail. > > * The user may explicitly close a cursor handle. In this case, the > underlying object is closed, and the handle is marked invalid. > (Same as above.) > > * The user may explicitly close a table handle. In this case, all > cursor which are still open are closed. Future operations on > them, or the table, will fail. > > * When the program exits, all cursors and tables shall be closed, > even if the program was termined by an exception. > > (Here, "to fail" means to raise an exception or some other kind of > deterministic error signaling mechanism.) This will be hard to do if you really want to be complete. Some run- time errors (most notably, "out of memory") are not exceptions, they stop the program immediately. Moreover, under Unix there are signals that cannot be caught or ignored. > Usually, application code will gracefully close all cursors, and the > table, but I want my library to be as safe as possible to use, and > avoid random crashes or memory leaks. > > There are a couple of approaches to implement the desired behavior: > > (1) Just use weak arrays of tables and cursor, together with > Gc.alarm. > > (2) Use Gc.finalise for handler objects which contain an index into > (plain) arrays of tables and cursors. Use reference counting > (or back pointers) to prevent premature finalization of table > objects while there are still cursors around. A simple pointer from the cursor to the table should be enough. > (3) Same as (2), but using custom blocks and C code. You'd need reference counts in this case. I can't see how (1) would work. (2) is normal if your objects are implemented as OCaml data structures. (3) if they are implemented by some C library. > (4) Some hybrid approach. > I'm not exactly happy with each appraoch because it seems I must > implement a simple memory manager on my own for managing the array > elements. Perhaps I'm missing something? Maybe simply that when you implement a program, you have to do some of the work, the GC cannot do everything for you... > How is the performance of the three approaches? Each one uses a > different GC mechanism to achieve its goals, so I'm a bit puzzled. Different mechanisms for solving different problems.
Archive: http://thread.gmane.org/gmane.comp.lang.caml.general/31241Alessandro Baretta asked and Maxence Guesdon answered:
> Is anyone still using the clever ioXML syntax extension by Daniel de Rauglaudre? > Has anyone updated it to ocaml 3.08.4? 3.09.0? > > I believe Maxence's Cameleon used to depend on it. Is it still so? Hello Alex, I had to update it in cameleon, since I encountered errors with "loc" ids. I changed all "loc" variables in the code to "_loc" (file pa_ioXML.ml). Later, I was told that the -loc option of camlp4 was made for this usage. So a 'camlp4 -loc fooo' should work, but I did not test.
Archive: http://thread.gmane.org/gmane.comp.lang.caml.general/31252Jon Harrop announced:
Here is a little OCaml program to solve Sudoku puzzles: http://www.ffconsultancy.com/free/sudoku/
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