Re: libpspp + Perl module somewhere down the road?

[Ben Pfaff]

Jörg Beyer <address@hidden> writes:

> But don't expect too much, and please bear with me, I'm
> not a trained programmer.

Neither am I, but it's never seemed to stop me ;-)

> As I already wrote in another thread, I see PSPP as an integral part of some
> kind of a larger ecosystem for data analysis.

That's a great way to look at it.  I'd like to work toward making
this closer to reality.

> Right now, I'm in quite a bit difficult situation. On top of my wish list is
> having a libpspp and associated Perl bindings/a Perl module. I need to read
> at least the dictionary of an arbitrary *.sav-file with Perl; it would also
> be of value if I could read the data part. In both cases, getting either a
> data structure or a text report would be great, but the former is preferred,
> that would release me from writing parsers.

I want to have bindings to other languages also, in the long
term.  In the past I have done a little bit to discourage
building support for this, because I didn't think that PSPP was
ready for it, but I think that the time is about right.  If
anyone wanted to work on this, then at this point I would be
happy to work toward integrating it into the PSPP tree.

John Darrington at one point mentioned that he was working on
Python bindings as a side project for (I believe) an Australian
company.  I do not know the status of that project or whether he
would be willing to contribute the result back to PSPP.

> While similar ideas have been discussed elsewhere (e.g. in a thread back in
> June), I wonder what your current plans are:
>
> (1) Is a libpspp in the works (there seem to be some hints in the alpha
> snapshot of October 3rd, but only an empty directory was installed in
> /usr/local/lib on my machine)?

There is a directory named "libpspp" in the source tree, but it
is not what you are looking for.  (It is a directory of library
routines used internally by PSPP.)

> (2) What are your plans about releasing an associated Perl module alongside?
> Or better, are there any plans at all, and if, when approximately?

There are no plans, but I would be open to accepting code to
support Perl.

> Given the fact that I know near to nothing about C (or how to use XS or Swig
> to bring C and Perl together), I have two alternatives:
> -- If you have something in the works, I could wait a bit and hope that it
> works for me. 
> -- I could also sit down and try to write my own parser in pure Perl.

As a third alternative, you might have a look at
src/data/sys-file-reader.c in the PSPP to figure out how many
actual dependencies it has on the rest of the PSPP source base.
Possibly, it could be extracted from the source without a lot of
trouble.

I hope you noticed the extensive documentation on the PSPP data
file format that is included in the PSPP manual.  This could help
with the implementation of your own parser, if you decide on that
alternative.
-- 
"Mon peu de succès près des femmes est toujours venu de les trop aimer."
--Jean-Jacques Rousseau