[cwn] Attn: Development Editor, Latest Caml Weekly News

Alan Schmitt alan.schmitt at polytechnique.org
Tue Mar 20 02:41:58 PDT 2007


Hello,

Here is the latest Caml Weekly News, for the week of March 13 to 20,  
2007.

1) Style and organization of code
2) OCaml Project in Google Summer of Code
3) Imbedding a DSL into Ocaml: Camlp4
4) Announcing OMake 0.9.8.1
5) ocamlyacc, menhir, dypgen, camp4, elkhound
6) Examples of parsing XML

========================================================================
1) Style and organization of code
Archive: <http://groups.google.com/group/fa.caml/browse_frm/thread/ 
21111d096cc38ea2/a4b6803d52ed2a20#a4b6803d52ed2a20>
------------------------------------------------------------------------
** Ian asked, Gabriel Kerneis and Maxence Guesdon answered:

 > > I'm looking for a guidebook or just some rules of thumb on how  
to organize
 > > my OCaml code.
 >
 > If you can read french :
 > <http://caml.inria.fr/pub/old_caml_site/FAQ/pgl-fra.html>

This page and its english version were ported to the new site some
months ago:
<http://caml.inria.fr/resources/doc/guides/guidelines.fr.html>
<http://caml.inria.fr/resources/doc/guides/guidelines.en.html>
			
========================================================================
2) OCaml Project in Google Summer of Code
Archive: <http://groups.google.com/group/fa.caml/browse_frm/thread/ 
13b04f870253f02d/7f45ca175b7eed9b#7f45ca175b7eed9b>
------------------------------------------------------------------------
** Yoriyuki Yamagata announced:

The FreeSoftware Initiative Japan(<http://www.fsij.org/>) is looking for
participants of Google Summer of Code(<http://code.google.com/soc>).
Proposed ideas (<https://members.fsij.org/trac/soc2007/wiki/Ideas>)
include OCaml related projects.
We also accept proposals not directly related to proposed ideas.  If
your project is selected, you are paid 4500$ from Google.
Please read carefully <http://code.google.com/soc/tos.html> and
<https://members.fsij.org/trac/soc2007/wiki/Ideas> before submitting
your proposal.  Feel free to ask me if you have a question.

OCaml projects are

*Improve OCaml internationalization

There is no specific requirement. The idea includes

     - Create a syntax extension which handle Unicode strings and
locale-sensitive messages. Create a Unicode-based, locale-sensitive
alternative of the standard library.
     - Create a binding of ICU. Binding must not be bare-bone wrapping.
It must be well integrated to OCaml and its programming customs.

We accept other ideas as well.

* Create Ajax development tool for OCaml

Enable seamless Web development by generating JavaScript from OCaml
and integrating it to Web framework.

* Improve Eclipse plugin of OCaml

There is no specific requirement. Please propose suitable improvements.

Also we have a project about automatic source code verifiers.

*Automatic program verifier

Develop an automatic program verifier with the following features.

     - Accept any programs in popular programing languages such as
C/Java/Ruby and so on.
     - Produce correct answers for programs in a practical subset of
the language.
     - Produce approximate answers for all programs in the language.
     - Performance is not a goal. It suffices to demonstrate its
capability to small code fragments. However, it must have modular
design to future improvement.
			
========================================================================
3) Imbedding a DSL into Ocaml: Camlp4
Archive: <http://groups.google.com/group/ocaml-developer/browse_frm/ 
thread/532cfd6cc675e98b>
------------------------------------------------------------------------
** Hugo Ferreira asked and Francisco Valverde answered:

 > I have the need to use some logical programming functionality  
within my
 > application. I would like to embed this into my Ocaml code as a  
domain
 > specific language. I am contemplating the use of Camlp4 for this. M

I recall reading an impressive presentation on how to do this (at least
partially) in OCaml. Hold on... Yes, the wikipedia has the missing  
link! ;)
<http://www.venge.net/graydon/talks/mkc/html/mgp00002.html>
			
========================================================================
4) Announcing OMake 0.9.8.1
Archive: <http://groups.google.com/group/fa.caml/browse_frm/thread/ 
f4460a94f244e6ed/9ed1ec7694e27cf6#9ed1ec7694e27cf6>
------------------------------------------------------------------------
** Aleksey Nogin announced:

We are proud to announce the latest release of the OMake Build System -
OMake version 0.9.8.1.
OMake is a build system designed for scalability and portability. It
uses a syntax similar to make utilities you may have used, but it
features many additional enhancements, including the following.

    - Support for projects spanning several directories or directory
      hierarchies.

    - Fast, reliable, automated, scriptable dependency analysis using  
MD5
      digests, with full support for incremental builds.

    - Fully scriptable, includes a library that providing support for
      standard tasks in C, C++, OCaml, and LaTeX projects, or a mixture
      thereof.

      Often, a configuration file is as simple as a single line

      .DEFAULT: $(OCamlProgram prog, foo bar baz)

      which states that the program "prog" is built from the files  
foo.ml,
      bar.ml, and baz.ml. This one line will also invoke the default
      standard library scripts for discovering implicit dependencies in
      OCaml files.

    - Full native support for rules that build several files at once.

    - Portability: omake provides a uniform interface on Linux/Unix
      (including 64-bit architectures), Win32, Cygwin, Mac OS X, and  
other
      platforms that are supported by OCaml.

    - Built-in functions that provide the most common features of  
programs
      like grep, sed, find, and awk. These are especially useful on  
Win32.

    - Active filesystem monitoring, where the build automatically  
restarts
      whenever you modify a source file. This can be very useful during
      the edit/compile cycle.

    - A built-in command-interpreter osh that can be used interactively.

OMake preserves the style of syntax and rule definitions used in
Makefiles, making it easy to port your project to OMake. There is no
need to code in Perl (cons), or Python (scons). However, there are a few
things to keep in mind:

   1. Indentation is significant, but tabs are not required.
   2. The OMake language is functional: functions are first-class and
      there are no side-effects apart from I/O.
   3. Scoping is dynamic.

OMake is licensed under a mixture of the GNU GPL license (OMake engine
itself) and the MIT-like license (default configuration files).

Additional information and extensive documentation can be found on OMake
Home Page at <http://omake.metaprl.org/>

OMake version 0.9.8.1 is a minor feature enhancements and bugfixes
release. The changes in this version include:

   - Added a large number of new built-in and standard library functions
   - Extented the autocomfiguration section of the standard library
   - A number of improvements in the interactive osh shell.
   - A number of improvements in the library of standard build recipes
   - Documentation improvements.
   - A number of other improvements and bugfixes.

For a more verbose change log, please visit
<http://omake.metaprl.org/changelog.html#0.9.8.1> .

Source and binary packages of OMake 0.9.8.1 may be downloaded from
<http://omake.metaprl.org/download.html> . In addition, OMake may be
obtained via the GODI packaging system.

To try it out, run the command "omake --install" in a project directory,
and modify the generated OMakefile.

OMake 0.9.8.1 is still an alpha release.  While we have made an effort
to ensure that it is bug-free, it is possible some functions may not
behave as you would expect.  Please report any comments and/or bugs to
the mailing list omake at metaprl.org and/or at <http:// 
bugzilla.metaprl.org/>
			
** Nathaniel Gray added:

FYI, the OS X PPC package is now available.
			
========================================================================
5) ocamlyacc, menhir, dypgen, camp4, elkhound
Archive: <http://groups.google.com/group/fa.caml/browse_frm/thread/ 
02477e8de62fb685/49c2373ee8189931#49c2373ee8189931>
------------------------------------------------------------------------
** Christophe Raffalli asked:

The programs listed in the subject of this mail are parser generators
for OCaml ...
There may be others, and there is also the possibility to write parsers
by hand using stream pattern matching, parser combinators, etc ...
(the later technics are not covered here)

It would be nice to have a small comparison table to help people making
a decision ? Being not neutral
(dypgen was developped by a student at ENS lyon under my direction) I
think I should not do it myself ...

But I gave it a try. Here is a first draft (This table is not correct
yet and should not be used to make a decision ;-)

<http://www.lama.univ-savoie.fr/~raffalli/ocaml-parsing.html>

The html produced by ooffice is poor and the calculator example is not
well presented due to an ooffice bug (I think).

Questions

- Can you help me complete the table (missing lines, columns,
inaccurate or missing information) ?
- Can you provide the best possible calculator example for the other
parser as a text file ?
- Can you provide a really difficult but short grammar to make a better
comparison ?
- Other Idea welcome
- If someone neutral wants to volonteer to host this comparison table, I
will be very please to send him the source of the table.
			
** Aleksey Nogin answered:

I am not an expert in camlp4, but I probably know enough to be able to
fill in a few blanks in the last column of your table. My answers are
based on "old" 3.09 camlp4 and might be different for the new 3.10 one.

Handled grammar: LL(1)

Reentrant: Yes, but with caveats(*1)

Extensible (an action can change the grammar): Yes(*2)

Parametrized non terminal: No (???, *3)

Splitting the definition of a non terminal: Yes

Grammars parametrized by Ocaml modules: ??? (Yes? - *4)

Partial action: No

Ambiguous grammars: Yes (???, *5)

Exception to reject a rule: No (???)

Priority: Using levels (= a partial order as a relation) + associativity
direction

Debugging grammars: hard

---

(*1) In 3.09, reentrant parsing works, except the error messages might
end up pointing to the wrong place in the source stream (supposed to be
fixed in 3.10, AFAIK). However, there is no good way of passing a state
to the grammar actions. As a result, one often has to resort to using a
global ref to hold the state, which, obviously, kills the ability to be
reentrant.

(*2) For example, see the pa_macro where the action for the DEFINE and
UNDEF expressions change the grammar accordingly.

(*3) As far as I understand, only tokens
can be parameterized, although that might have changed in 3.10.

(*4) I am not sure which capability exactly is meant here. In Camlp4,
the grammar definitions/extensions can be done inside a body of a
functor. The actual grammar is created when the functor is applied.

(*5) Not sure what is meant here. In camlp4, unfortunately, there is no
way to test the grammar for ambiguities - it accepts an ambiguous
grammar without any warnings.
			
========================================================================
6) Examples of parsing XML
Archive: <http://groups.google.com/group/ocaml-developer/browse_frm/ 
thread/e4882cb3243d3114>
------------------------------------------------------------------------
** Gordon asked and Daniel answered:

 > Does anyone have any moderate level examples of parsing XML using a
 > SAX style parser to build data structures?  I'm trying to use  
Expat to
 > do some XML parsing and I just seem to be having a mental block as to
 > how to build up a data structure in this style.

The examples on this page [1] may help. They show how to build the
document tree using a SAX style parser.
Daniel

[1] <http://xmlm.googlecode.com/svn/trunk/distrib/xmlm-0.9.0/doc/ 
Xmlm.html#ex>
			
========================================================================
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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<http://lists.idyll.org/listinfo/caml-news-weekly/> .

========================================================================

-- 
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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