[Nexus] Problems with NXgetnextentry

[Mark Koennecke]

Dear Paul Simmonds,

On Wed, 28 May 2003, Simmonds Paul wrote:

> Mark Koennecke wrote:
> <snipped>
> 
> >   - We are currently working on a general interface between the NeXus-API
> >     and scripting languages using SWIG (http://www.swig.org). This SWIG
> >     interface is already known to work for Tcl and mzScheme. I would like
> >
> Thanks Mark,
> I have already had a look at SWIG, and it does interface with Python very
> well. However, it provides a very transparent layer: the Python objects
> are fine, but the attributes to those objects are C objects, and so are
> untreatable in a Python context. C functions also take a precise number
> of arguments, so optional or default arguments are not possible if only
> the thin layer SWIG provides is used.
> 
> What I'm aiming for is something more malleable, allowing the user to
> create and manipulate NeXus files from the Python interpreter interactive
> prompt. This then would act almost like a text-based browser, complete
> with support for Python's help and documentation, which SWIG does not
> support (yet?). It would then be a relatively simple matter to create a
> GUI browser using one of the GUI interfaces.
> 
  If you come up with something nice please make it public.

> That's just what I was looking for. I didn't want to create my own
> arbitrary maximum lengths, and didn't find NXname. Thanks for pointing
> that out, especially as it seems some of my code was working by accident.
> 
> In the hierarchy, though I find a group named with what was (I assume)
> the original filename, with a class of "CDF0.0". In each of the files I
> have tried, I found a few levels under that a group of class "UNKNOWN".
> The API doesn't know how to open this, so an error is returned. I haven't
> found a reference to these class types anywhere.
> 
   Ignore that CDF0.0. It has nothing to do with NeXus. It is an internal
   thing of HDF, if I'am not mistaken HDF keeps dimension attributes in
   there. It is wise to leave that one alone. 


				Mark Koennecke