[cwn] Attn: Development Editor, Latest Caml Weekly News
Alan Schmitt
alan.schmitt at polytechnique.org
Tue Apr 22 00:51:01 PDT 2008
Hello,
Here is the latest Caml Weekly News, for the week of April 15 to 22,
2008.
1) Non-tail return
2) unsigned 64-bit integer library
3) forge.OCamlCore.org is now ready to serve the OCaml community
4) OCaml Summer Project decisions are in
5) xsetxmap, unfunctorized, Sexp-lib aware versions of Set and Map
6) Help needed for benchmarking OCaml on AMD64
7) GODI Search
========================================================================
1) Non-tail return
Archive: <http://groups.google.com/group/fa.caml/browse_frm/thread/8eb3da70eef2d4ff#
>
------------------------------------------------------------------------
** Seo Sanghyeon announced:
Richard Jones suggested that type-safe return statement which
immediately returns from the innermost function would be useful. So I
developed an implementation. His sample code (from Extlib) works
as-is.
<http://sparcs.kaist.ac.kr/~tinuviel/devel/ocaml/>
Some notes:
* This depends on nontail exit patch I did as a part of break/continue
patch. break-continue-v2 was broken to break-continue-v3 and
nontail-exit-v1.
* A stack of function's return type is maintained. "return e" causes
unification of "e" and return type on the top of the stack. "return e"
itself is typed as unit.
* Function is translated with implicit catch around body, and return
is translated to raise. Simplification removes implicit catch when no
return is used, so existing codes should compile same.
========================================================================
2) unsigned 64-bit integer library
Archive: <http://groups.google.com/group/fa.caml/browse_frm/thread/8f7514a44bffe815#
>
------------------------------------------------------------------------
** Jeff Shaw announced:
If you would like to use C's unsigned long long type in ocaml, please
try my
library. I've tested it only on Mac OS X ppc32, ocaml 3.10.x. Please
let me
know about any modifications I should make; for instance, I don't know
how to
make the library work in windows. Also I haven't tested storing
UInt64.t in
hashtables much yet.
<http://www.msu.edu/~shawjef3/uint64lib.zip>
Quick instructions:
unzip uint64lib.zip
cd uint64lib
ocaml compile.ml
ocaml uInt64.cma
#install_printer UInt64.printer16;;
UInt64.of_string "0x123456789abcdef";;
========================================================================
3) forge.OCamlCore.org is now ready to serve the OCaml community
Archive: <http://groups.google.com/group/fa.caml/browse_frm/thread/8b37e68756ea2669#
>
------------------------------------------------------------------------
** Stefano Zacchiroli announced:
**OCamlCore.org is ready!**
During the last few weeks, the OCamlCore.org Team, with the help of
many other
members of the community, worked hard to fix a number of problems on
the site.
Now we think it is ready for prime time. Therefore, following from the
previous announcement [1][2] of the availability of an OCaml planet
and the
OCaml forge beta testing, we are now ready to allow full public access
to
OCaml forge.
[1] <http://groups.google.com/group/fa.caml/msg/6faedd72f77fd0df>
[2] <http://groups.google.com/group/fa.caml/msg/f8342697120413fd>
A forge is a set of services for software projects, including version
control systems (CVS, SVN, ...), mailing lists, download areas, bug
tracking systems, ... Well known examples are sourceforge.net, GNA, and
Savannah. The forge for the OCaml community [3] will be specifically
aimed at hosting software projects related to the OCaml programming
language.
[3] <http://forge.ocamlcore.org/>
This new forge has been beta tested, but you could still found some
bugs. In
this case, don't hesitate to submit bug to the Site Admin project [4]
[4] <http://forge.ocamlcore.org/projects/siteadmin/>
So if you want to start an ocaml project on forge.ocamlcore.org, sign-up
for an account on: <http://forge.ocamlcore.org>
We want to limit the use of this forge to OCaml related project. This
include
software or library written in OCaml, but also projects around OCaml,
using
derived languages (JoCaml, OCamlDuce, ...) or providing service for
OCaml
community (tools for conference organization...).
Help needed
-----------
At the moment, we have set up an hosting service for git and darcs
(git.ocamlcore.org and darcs.ocamlcore.org). We are looking for
experienced forge administrator that can allow us to manage this two SCM
through GForge. Contact us if you are interested.
We are also looking for talented web designer to make the look of
ocamlcore.org nicer. Join the project ocamlcore-theme and read the
README file to know how to proceed...
<http://forge.ocamlcore.org/projects/ocamlcore-theme/>
<http://forge.ocamlcore.org/plugins/scmsvn/viewcvs.php/trunk/README.txt?root=ocamlcore-theme&view=markup
>
Regards,
the OCamlCore.org Team.
(Sylvain Le Gall, Romain Beauxis, Stefano Zacchiroli, Pietro Abate)
PS: you will find the classical LGPL with static linking exception
License at the end of the license list when you create your project
========================================================================
4) OCaml Summer Project decisions are in
Archive: <http://groups.google.com/group/fa.caml/browse_frm/thread/589516b94adbc00f#
>
------------------------------------------------------------------------
** Yaron Minsky announced:
And the project descriptions are up for your perusal.
We chose 6 projects out of the more than 30 that we received this year.
This page has links to the full text of the accepted proposals.
<http://osp.janestcapital.com/wordpress/?p=22>
========================================================================
5) xsetxmap, unfunctorized, Sexp-lib aware versions of Set and Map
Archive: <http://groups.google.com/group/fa.caml/browse_frm/thread/8da1e4db5efee389#
>
------------------------------------------------------------------------
** Berke Durak announced:
I decided to share my modification of the standard Set and Map modules.
Basically, I took Set and Map, unfunctorized them, passing the
comparison
function as an optional argument with Pervasives.compare as the
default, added
or exposed some missing functions (reverse_fold, reverse_iter,
min_key...) and
added converters for Sexplib.
It is under LGPL and feel free to include it in Extlib, in Ocaml
"batteries"
or anywhere else.
<http://abaababa.ouvaton.org/caml/xsetxmap-20080421.tar.gz>
** Jean-Christophe Filliâtre said and Berke Durak replied:
> Since your library is allowing the user to pass the comparison
function
> to any function which requires it
>
> type 'elt cp = 'elt -> 'elt -> int
> val add: ?cp:'elt cp -> 'elt -> 'elt t -> 'elt t
> val mem: ?cp:'elt cp -> 'elt -> 'elt t -> bool
> ...
>
> you should really add a *huge* warning in the documentation saying
that
> it is unsound to insert an element with a comparison function and
then
> to search for it using another one.
>
> This is precisely where the functor approach is increasing your
program
> correctness, with a static binding of a single comparison function
into
> the code of all operations.
>
> Even without functors, you can provide a safer approach where the
> comparison function is given when creating the data structure (a la
Caml
> light), and stored inside. This can be an optional argument of create
> for instance, so that you keep your idea of a default comparison
function:
>
> val create: ?cp:('elt -> 'elt -> int) -> unit -> 'elt t
>
> (Note that I agree with you that it is sometimes annoying that Set
and
> Map do not provide polymorphic versions using Pervasives.compare, as
> Hashtbl does with the polymorphic hash funtion. I'm only concerned
with
> the potential risk with your solution...)
Yes you are right, I should have put a warning. These modules are for
peculiar
cases.
So here it is:
WARNING: The default comparison function is not sound for non-canonical
datastructures such as Sets and Maps. Xset is not canonical. Do not
use Xsets
or Xmap without providing the correct comparison function. You must
always
pass the same comparison function.
(That's why I was asking if there was a Set/Map structure with canonical
representation the other day.)
Extlib provides a version where the comparison function for the keys
is stored
in the map.
But I chose to not do this for some peculiar reasons.
- I'm serializing Xmap and Xsets using Marshal, and I don't want to have
functions in the structure
- I don't like the overhead of a wrapper structure and I don't want to
complicate the API
========================================================================
6) Help needed for benchmarking OCaml on AMD64
Archive: <http://groups.google.com/group/fa.caml/browse_frm/thread/143400f320ed61b1#
>
------------------------------------------------------------------------
** Alain Frisch asked:
The new native dynamic linking feature requires some changes in the code
generator for (non-Windows) AMD64 targets. Currently, this change is
enabled by passing the -dlcode option to ocamlopt. A module which has
not been compiled with this option cannot be dynlinked.
Because -dlcode is only needed for AMD64 and it didn't exist before,
most 3rd party libraries will likely not include this flag in their
build system any time soon and they will thus be impossible to dynlink.
This is not very satisfactory.
A question to be answered before the release of OCaml 3.11 is whether
this option should be enabled by default (and maybe provide another
option to disable the new behavior). The only reason not to do so would
be a degradation of performance. I haven't observed any difference on
small benchmarks I did some months ago, but I'd like to collect more
benchmarking data before enabling -dlcode by default.
It would be great if some people could checkout the current CVS tree and
try to compile and run their time-consuming programs with or without
-dlcode on AMD64 systems, and report what they found out. I expect
potential differences to appear only for functionally intensive code (a
lot of inter or intra module function calls). To help benchmarking, the
current CVS includes the following hack: if the environment variable
OCAML_DLCODE is set to a non-empty value, ocamlopt behaves as if -dlcode
were enabled. It is thus trivial to recompile (e.g. via GODI) any 3rd
party library which your code may depend on.
Any help will be appreciated!
========================================================================
7) GODI Search
Archive: <http://groups.google.com/group/fa.caml/browse_frm/thread/12076c9944dd37eb#
>
------------------------------------------------------------------------
** Gerd Stolpmann announced:
I've just released a new feature on docs.camlcity.org that is very
interesting for GODI and non-GODI users of O'Caml. It is a search engine
that allows you to search for identifiers and other words in an (almost)
full-blown GODI installation. I've developed this engine for the last
three weeks, and the results are already very interesting.
Just try it out here:
<http://docs.camlcity.org>
You can search for definitions of functions like "Hashtbl.fold", other
identifiers like "in_obj_channel", or just for "Xavier Leroy". The
search engine has some O'Caml parsing capabilities, and can e.g.
distinguish between value and type identifiers.
For the query syntax see
<http://docs.camlcity.org/docs/syntax.html>
The syntax resembles Google's.
The engine is not yet perfect. A number of errors are listed in the FAQ
document:
<http://docs.camlcity.org/docs/faq.html>
I would be glad to hear of more shortcomings - so I can fix or at least
document them soon. Feature wishes and other comments are also welcome.
========================================================================
Using folding to read the cwn in vim 6+
------------------------------------------------------------------------
Here is a quick trick to help you read this CWN if you are viewing it
using
vim (version 6 or greater).
:set foldmethod=expr
:set foldexpr=getline(v:lnum)=~'^=\\{78}$'?'<1':1
zM
If you know of a better way, please let me know.
========================================================================
Old cwn
------------------------------------------------------------------------
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========================================================================
--
Alan Schmitt <http://alan.petitepomme.net/>
The hacker: someone who figured things out and made something cool
happen.
.O.
..O
OOO
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