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

Tue Jan 27 00:46:53 PST 2009

Hello,

Here is the latest Caml Weekly News, for the week of January 20 to 27,  
2009.

1) CamlPDF 0.4 Released
2) Building with OCamlMkLib
3) Conditional compilation wrt OCaml version?
4) Tail calls in the JVM and the OCamlJava project

========================================================================
1) CamlPDF 0.4 Released
Archive: <http://groups.google.com/group/fa.caml/browse_thread/thread/edec98d697b4dd2b# 
 >
------------------------------------------------------------------------
** John Whitington announced:

I've just updated CamlPDF to version 0.4:

<http://www.coherentpdf.com/ocaml-libraries.html>

The biggest change is that this release now compiles with Microsoft F  
Sharp as
well as with OCaml.

Some major non-compatible changes have been made to the low-level API,  
due to
our experience of building large software with the library. These  
should be
the last such changes, at least to the basic modules.

One of the changes is that many functions which used to take a  
Pdf.pdfdoc and
return another one now modify the document in-place. This is rather
un-idiomatic for a functional library, but threading all the documents  
through
complicated functions in code using CamlPDF became wearying.

There are several new modules:

PDFSpace (Parsing Colourspaces)
PDFText module extended for more encodings and better text extraction
Cff (Parse Type 1 fonts and convert to Type 3)
PDFMarks (Bookmark handling - unfinished)
PDFAnnot (PDF Annotations - unfinished)
PDFGraphics (Structured graphics - unfinished - included only because  
Cff uses
it

This release is about a third faster in general than the last one, due  
to
profiling under .NET. Many bug fixes are included, and extra  
facilities for
dealing with malformed PDF files.

CamlPDF is in commercial use in our Command Line PDF Toolkit and PDF  
Toolkit
for .NET.

========================================================================
2) Building with OCamlMkLib
Archive: <http://groups.google.com/group/fa.caml/browse_thread/thread/66ad4b2458f93d08# 
 >
------------------------------------------------------------------------
** At the end of this thread, John Whitington said:

On 20 Jan 2009, at 17:03, John Whitington wrote:
 > I'm building a Plain C interface to our PDF libraries, but am  
stuck. The idea
 > is to build a library with Ocamlmklib containing the C wrapper  
around the
 > ocaml code.

Thanks to those who helped me here - I finally settled on a modified  
version
of what's given in 18.8 in the manual.

Here are the new files:

<http://www.coherentpdf.com/solution.tar.bz2>

And here's what we ended up with...

ocamlc cpdflibc.mli
ocamlopt cpdflibc.ml
ocamlc cpdflibwrapper.c
ocamlopt -output-obj -o cpdflibc.o cpdflibc.cmx
cp /usr/local/lib/ocaml/libasmrun.a cpdflib.a
ar r cpdflib.a cpdflibc.o cpdflibwrapper.o

....producing the final cpdflib.a with which we can do...

cc -o test test.c cpdflib.a

....to use the library.

========================================================================
3) Conditional compilation wrt OCaml version?
Archive: <http://groups.google.com/group/fa.caml/browse_thread/thread/c22ffa51bd7fbbc3# 
 >
------------------------------------------------------------------------
** David Teller-Rajchenbach asked:

   Working on Batteries, we're faced with a few places where we'd like  
to
perform conditional compilation depending on the version of OCaml being
used. We could probably do this with Camlp4, cpp, Autoconf hackery, etc.
-- but first, we need to decide on which of these options we'll adopt. 

Any suggestion?

** Sylvain Le Gall suggested:

There is optcomp:
<https://forge.ocamlcore.org/projects/optcomp/>
<http://darcs.ocamlcore.org/repos/optcomp/optcomp/README>

The example in README should talk to you directly.

** Mikkel Fahnøe Jørgensen suggested:

If you are interested in using ocamlbuild you can have a look at
ocamlbuild-ctools:

<http://dvide.com/labs/ocamlbuild-ctools/>

I added extensions to ocamlbuild using a syntax like

normalfile.o
[mytag,myothertag,~notthistag]
conditionalfile.o
....

this is done in a .cprog file that lists all files to include, but
that same could be done with other similar files e.g. .mllib

Also, I added multi-variant builds so the same build can handle
multiple build targets based on tags - for example debug and release
builds. Multivariant builds work by adding tags in the filename:
myfile.variant_release,mingw.o

Most of this could be integrated into ocamlbuild, but ocamlbuild is
not very actively maintained as I understand.

========================================================================
4) Tail calls in the JVM and the OCamlJava project
Archive: <http://groups.google.com/group/fa.caml/browse_thread/thread/80d88a5df82886dd# 
 >
------------------------------------------------------------------------
** Jon Harrop said:

For anyone who missed it, there has been a very interesting  
development in JVM
land. Arnold Schwaighofer claims to have the first working  
implementation of
tail calls on the recently open sourced Hotspot Java compiler:

  <http://mail.openjdk.java.net/pipermail/mlvm-dev/2009-January/000331.html 
 >

Given the existence of the OCamlJava project, this should be of great  
interest
to the OCaml community because it might pave the way to even better  
numerical
performance and easier parallelism with simple interop to rich  
libraries and
so forth.

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