Hello

Here is the latest Caml Weekly News, for the week of July 16 to 23, 2013.

1. Ubuntu PPAs for OCaml (4.00 and 4.01dev)
2. Batteries 2.1
3. Request for feedback: Procord, a library to delegate tasks to other processes
4. ocamlnet-3.6.6
5. GODI is shutting down
6. Other Caml News

Archive: https://sympa.inria.fr/sympa/arc/caml-list/2013-07/msg00121.html

I've put together two Ubuntu PPAs to make it more convenient to use modern
OCaml/OPAM versions on Ubuntu via binary packages.

OPAM stable:
https://launchpad.net/~avsm/+archive/ppa
This includes the latest stable OCaml (4.00.1) and OPAM (1.0.0).

OPAM unstable:
https://launchpad.net/~avsm/+archive/ppa-opam-unstable
This includes the latest snapshot of OCaml (4.01.0dev) and OPAM (1.0.1dev).
This should get you reasonably stable snapshot of both, and will include the
release candidates of OCaml when it's released.

For now, these are experimental PPAs as I muddle my way through learning how
Debian packaging works. Reports of breakage or success to me directly would
be appreciated. Most of this PPA was based on the excellent Debian package
sources, and thanks to Mehdid Dogguy in particular for the OPAM packaging.
      

Archive: https://sympa.inria.fr/sympa/arc/caml-list/2013-07/msg00128.html

It's been a while since 2.0, and batteries has had a bunch of improvements that
should be shared with a wider audience.

More features, more bugfixes, more batteries.

Thanks to the *many* contributors in this release; batteries exists because of
you.

E.

Changelog:

Added: 
Array.{avg,favg,singleton}, 
Bigarray.of_enum, 
Hashtbl.{modify,modify_def,modify_opt,map_inplace,filter_inplace,filter_opt_inplace}, 
IMap.{modify,modify_def,modify_opt}, LazyList.lazy_fold_right, 
List.{singleton,unfold,min_max,modify,modify_dep,modify_opt, span, nsplit, group_consecutive}, 
Map.modify_opt (*3), 
MultiMap.modify_opt (*3), 
MultiPMap.modify_opt (*3), 
Option.{default_delayed , map_default_delayed}, 
Set.find, Set.Incubator.op_map, 
String.rev, 
Substring.{equal,contains,iteri,enum}
Fixed:
Compilation with Ocaml 4.01
Speedup in LazyList.append
More organized magic for fast list snoc
Speedup in String.{replace,nreplace}
Cleanup int32.[un]pack exceptions
Fix last bit access in BatBitSet
Float.round corner case on predecessor of 0.5 fixed
Fix Enum.concat's clone implementation
Fix List.n_cartesian_product to allow empty input
Fix BatText.rfind's index calculation
Improve Pervasives.undefined to be curry-able
Array.backwards doesn't clone array anymore
Remove useless allocation in Splay.cfind
More unit tests, benchmarks
      

Archive: https://sympa.inria.fr/sympa/arc/caml-list/2013-07/msg00135.html

I plan on writing yet another library to help with concurrency in OCaml.
The motivations for this library, and the interface I have in mind, are
available here:

http://romain.bardou.fr/procord/api/Procord.html

Before actually implementing the library, I would be very happy to
receive feedback. I am interested to know, among others:
- whether I miss important information which would make the very
existence of this library stupid (such as, it already exists);
- whether I forgot some important use case;
- whether the names I chose have better ubiquitous equivalents;
- whether you believe I should choose another interface entirely, for
instance, if you don't like functors.
      

> Processing streams of data in parallel without having to read all the data
> in memory first.

Good point. I'm not sure how to deal with this and I actually think it
calls for a slightly different paradigm. Although maybe one could
eventually add send/receive functions to send/receive to/from an 'a
process, and the same for the worker. It would allow to transmit more
than one input and more than one output.

> You could sort of do this with your current interface but only on Unix
> (i.e. mkfifo and pass filename).
> Don't know what'd work on Windows, perhaps creating a (named) pipe, and
> sending the file descriptor to a newly spawned child?

I don't think there are named pipes on Windows but I may be wrong. Maybe
it can be emulated using files anyway. I don't think sending a file
descriptor is a good idea but sending a file name is of course possible.

> Also it'd be nice to have something similar to the reduce in map-reduce.

That's definitely something I want to be able to add easily. It won't be
in the initial version, as I have no need for it right now, but it is
important for me that it can easily be added, maybe as a new layer on
top of Procord itself.

>> - whether the names I chose have better ubiquitous equivalents;
>> - whether you believe I should choose another interface entirely, for
>> instance, if you don't like functors.
>
> I'd prefer if there was also a Lwt-like monadic interface, but it is not
> absolutely required (it could probably be done on top of your already
> existing interface).

That is also something I want to be able to add easily, but I don't want
Procord to depend on anything and to force one library. The user should
be able to choose Async or Lwt or whatever. This is why I propose
get_file_descriptors and process_status. It should be easy to write a
Lwt using that.

It would be possible to provide separate modules Procord_lwt and
Procord_async as interfaces though.
      

Archive: https://sympa.inria.fr/sympa/arc/caml-list/2013-07/msg00152.html

I'm happy to announce ocamlnet-3.6.6. This is a pure bug fixing release.

Details about this release can be found on the project page:

http://projects.camlcity.org/projects/ocamlnet.html

See ChageLog for a detailed list of changes:

http://projects.camlcity.org/projects/dl/ocamlnet-3.6.6/ChangeLog
      

Archive: https://sympa.inria.fr/sympa/arc/caml-list/2013-07/msg00199.html

Unfortunately, it is no longer possible for me to run the GODI
distribution. GODI will not upgrade to OCaml 4.01 once it is out, and it
will shut down the public service in the course of September 2013. The
website, camlcity.org, will remain up, but with reduced content. Existing
GODI installations can be continued to be used, but upgrades or bugfixes
will not be available when GODI is off.

Although there are still a lot of GODI users, it is unavoidable to shut
GODI down due to lack of supporters, especially package developers. I was
more or less alone in the past months, and my time contingent will not
allow it to do the upgrade to OCaml 4.01 alone (when it is released).

Also, there was a lot of noise about a competing packaging system for
OCaml in the past weeks: OPAM. Apparently, it got a lot of attention both
from individuals and from organizations. As I see it, the OCaml community
is too small to support two systems, and so in some sense GODI is
displaced by OPAM.

The sad part is that OPAM is only clearly better in one point, namely in
interacting with the community (via Github). In times where social
networks are worth billions this is probably the striking point. It
doesn't matter that OPAM lacks core functions like deleting all files when
a package is removed, and that it lacks many other features GODI has. So
there is some loss of functionality for the community (partly difficult to
replace, like GODI's support for Windows).

If somebody wants to take over GODI, please do so. The source code is
still available as well as the package directories. Maybe it is sufficient
to move the repository to a public place and to redesign the package
release process to give GODI a restart.
      

Thanks to Alp Mestan, we now include in the Caml Weekly News the links to the
recent posts from the ocamlcore planet blog at http://planet.ocaml.org/.

Batteries 2.1 released:
  https://forge.ocamlcore.org/forum/forum.php?forum_id=880

GODI is shutting down:
  http://blog.camlcity.org/blog/godi_shutdown.html

Creating Xen block devices with Mirage:
  http://www.openmirage.org/blog/xen-block-devices-with-mirage
      

Old cwn

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Alan Schmitt