Hello
Here is the latest Caml Weekly News, for the week of 09 to 16 November, 2004.
Archive: http://caml.inria.fr/archives/200411/msg00080.html
SooHyoung Oh announced:
I'm pleased to announce "ocamllex tutorial".
----------------------------
Abstract
This is a tutorial on how to use ocamllex which is distributed with Ocaml
language.
This document borrowed lots of part from flex manual.
Please mail all comments and suggestions to <shoh at compiler dot kaist dot
ac dot kr>
This tutorial is work-in-progress. The latest version can be found at
http://pllab.kaist.ac.kr/~shoh/ocaml/ocamllex-ocamlyacc/ocamllex-tutorial/index.html .
The companion tutorial for ocamlyacc will be available at
http://pllab.kaist.ac.kr/~shoh/ocaml/ocamllex-ocamlyacc/ocamlyacc-tutorial/index.html .
You can find the source of this document in ocamllex-tutorial-src.tar.gz.
For printing, pdf (A4 size) is presented, and there is html (tar.gz).
You can download the source of examples used in this document from
ocamllex-examples.tar.gz.
Last updated: 2004-11-10
Archive: http://caml.inria.fr/archives/200411/msg00081.html
SooHyoung Oh announced:
This is newer version of "ocamlyacc tutorial".
-----------------------------
Abstract
This is a tutorial on how to use ocamlyacc which is distributed with Ocaml
language.
Lots of part of this document are borrowed from the bison manual.
All license term in this document is NOT related with ocamlyacc; it is ONLY
for this document.
Please mail all comments and suggestions to <shoh at compiler dot kaist dot
ac dot kr>
This tutorial is work-in-progress. The latest version can be found at
http://pllab.kaist.ac.kr/~shoh/ocaml/ocamllex-ocamlyacc/ocamlyacc-tutorial/index.html .
The companion tutorial for ocamllex is available at
http://pllab.kaist.ac.kr/~shoh/ocaml/ocamllex-ocamlyacc/ocamllex-tutorial/index.html .
You can find the source of this document in ocamlyacc-tutorial-src.tar.gz.
For who wants the other form, pdf (A4 size) for printing and html (tar.gz)
are presented.
The source of the examples used in this document can be found
ocamlyacc-examples.tar.gz.
Last updated: 2004-11-10
Archive: http://caml.inria.fr/archives/200411/msg00085.html
Owen Gunden announced:
O'Caml ANSIColor is a library for creating colorful text and other
effects in ANSI-compatible terminals. The code is staggeringly simple,
and the interface and implementation are both very roughly based on
Term::ANSIColor (a CPAN module).
Homepage: http://projects.phauna.org/ansicolor/
API: http://projects.phauna.org/ansicolor/doc/
Tarball: http://projects.phauna.org/ansicolor/release/ansicolor-0.5.tar.gz
GODI package: godi-ansicolor*
*: currently there is only a godi package for the 3.08 GODI
distribution. If there is demand and someone is willing to test with
3.07 I will gladly put the package into the 3.07 distribution as well.
That is all.
Archive: http://caml.inria.fr/archives/200411/msg00100.html
Alex Baretta asked:
We are writing a library implementing binary client-server protocol
based on the Marshal module. In order to guarantee some degree of
type-safety, during the handshaking phase of the communication we need
the client to send the server the MD5 checksums of all relevant modules.
The server process must verify that it has all the mentioned modules and
that the checksums are consistent with its own.
We are currently generating MD5 checksums from our source files with the
md5sum command. These checksums are then assembled into a new source
file which is compiled and linked into the both executables. This
process works coherently for byte and native code, but it has at least
one important drawback: all relevant modules must be available as source
files for the md5 source file generation to work. Besides, this makes
the compilation process exceedingly complex.
We have found that the md5sum can be fetced directly from the executable
file associated to the process. This technique is documented nowhere, as
far as I can see, but the source code of Symtable.init_toplevel is very
informative as to how to do this for bytecode executables. What I would
like to know is how to implement this technique for native code
executables. Essentially, how am I supposed to parse the binary
executable to extract the symtable information. Also, how am I supposed
to figure out at runtime whether I must use the bytecode method or the
native code method? Equivalently, how do I know at runtime if the
process is running a bytecode executable or a native one?
Thank you very much.
Xavier Leroy answered:
> We have found that the md5sum can be fetced directly from the executable
> file associated to the process. This technique is documented nowhere, as
> far as I can see, but the source code of Symtable.init_toplevel is very
> informative as to how to do this for bytecode executables. What I would
> like to know is how to implement this technique for native code
> executables. Essentially, how am I supposed to parse the binary
> executable to extract the symtable information.
You cannot, because the checksums you mention (the digests of the
interfaces of the modules) are not included in ocamlopt-generated
executables. They are included only in ocamlc-generated executables (in
the CRCS section) for use with Dynlink and the toplevel.
At any rate, I think you're on the wrong tracks: the checksums you'll
find in the CRCS section of bytecode executable are those of module
interfaces, not of module implementations. To establish type
agreement between two processes communicating via
output_value/input_value, you really want the latter, not the former.
(Think of an abstract type implemented differently in the two
processes. For more details, see e.g. the ICFP'03 paper by Leifer,
Peskine, Sewell and Wansbrough.)
So, you're looking for convenient ways to collect checksums for module
implementations. An insight that might simplify your build process is
that while these checksums must be computed at compile-time (e.g. by
running md5sum on the source .ml files), they can be collected
together at run-time. For instance, you could preprocess the .ml
sources of interest so as to insert at the beginning
let _ = Registry.record_module "Modulename" "checksum"
where "Modulename" is the module name and "checksum" the outcome of
md5sum on the source file. The Registry.record_module function just
accumulates its arguments in a hashtable or association list, which
can then be consulted during the agreement phase of your protocol.
There are probably many other ways to do it. But I think your initial
idea (compute checksums of source files at compile-time) is the
correct one, it's just a question of implementing it in a way that
doesn't complicate your build process too much.
Archive: http://caml.inria.fr/archives/200411/msg00125.html
Vincenzo Ciancia announced:
Hi all, I am trying to write a complete, up-to-date, efficient and
correctly multithreaded binding to the fuse api for ocaml. Fuse is a
linux kernel module allowing filesystems to be implemented in user
space, see
http://www.sourceforge.net/projects/fuse
By now, OCamlFuse is complete and up-to-date, but multithreading has
troubles. Anyway, I declare the single-threaded version to be in
alpha-testing (i.e. internal, developers testing). Since I consider the
developers of any free-software projects to be everybody willing to
join, I announce it here, in the hope that someone will want to have a
look at my efforts and to test it, write some example filesystem in
ocaml, comment on the interface and possible improvements in
implementation, or even better to help with multithreading, which
"should" work but crashes under heavy load for mysterious reasons.
Help or advices for packaging are also wanted, since I don't know too
much about GODI or ocamlfindlib and have not so much free time to work
on this project. I will answer to any question on the ocamlfuse-devel
mailing list, please read the README to know fundamental issues.
The source lives in the cvs; you can find everything needed, including
the mailing list, on the sourceforge project page:
http://www.sourceforge.net/projects/ocamlfuse
I did everything in a hurry, and on a by-need basis, I am not an expert
user of the ocaml C interface, so if you have suggestions, don't
hesitate to tell me :)
Matt Gushee asked and Vincenzo Ciancia answered:
> I'm interested in this. First of all, what was wrong with the
> existing mlfuse library? (I'm not saying there's nothing wrong with
> it, I just don't know--hadn't tried it yet).
It's not up-to-date (fuse is going towards its 2.1 release, while the
existing mlfuse is for fuse 0.9), and it was not designed with
multithreading in mind. If the latter was not true, I would not have
rewritten it, however by now I must record a failure, since I did this
all to get multithreading working and had no success :/ I am going to
try to spot the problem this weekend - it's related to a previous
recent post of mine on this list.
Apart from this, a question to the list: to implement the read and write
operations I am constrained to string copying. Is there a way to share
a string with C in ocaml or should I roll my own "cstring" type and use
that, copying from/to strings using memcpy when necessary?
Archive: http://caml.inria.fr/archives/200411/msg00128.html
Julien Signoles announced:
I'm please to announce that a new (major) release (version 1.09.0) of the
calendar library is available at:
http://www.lri.fr/~signoles/prog.en.html
calendar is an ocaml library managing dates and times. The latest changes
follow. In particular, this release adds features of Richard Jones'
GregorianDate.
CHANGES:
* add Date.to_business and Date.from_business (Richard Jone's suggestion)
* add the optional parameter ?month to Date.days_in_year
(Richard Jones' suggestion)
* add Date.nth_weekday_of_month (Richard Jones' suggestion)
* Date: add some Christian dates (Richard Jones' suggestion)
* add Date.Period.ymd and Calendar.Period.ymds
* Printer: add the format string %i corresponding to the ISO-8601 notation
* Printer: ISO-8601 notation is now the default format
* add [equal] in all the modules
* Calendar.Period: bug fixed with negative period
* bug fixed in Calendar.to/from_unixfloat and Date.to/from_unixfloat
* bug fixed in weeks_in_year
Owen Gunden added:
And the godi package (godi-calendar) has been updated to version 1.09.0.
Give it a whirl!
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