[Kst] Datasources & metadata

[George Staikos]

On Wednesday 23 August 2006 09:13, Brisset, Nicolas wrote:
> I have added support for metadata in a very simple internal datasource
> to better understand how it works, and the status is the following:
> 1) I think it would be nice and fairly easy to consider each non-data
> line in the header of ASCII files as metadata, as well as global
> attributes in CDF and maybe the equivalent in netCDF since it surely
> exists (I have to look at the docs though). I know it's not high on
> George's TODO list, but he has prepared the support required to make it
> easy to add and I believe it is a very important feature. So, I may come
> around to preparing a patch for that if there is interest.

  Sure, feel free to add it yourself.  Send the patch and I'll have a look.

> 2) the metadata I generate is visible from the vectors' RMB in the data
> manager, as "advertised". However, if I generate a [Filename] string and
> use it in a label like "Data coming from [Filename]" the label shows
> "Data coming from ", whereas from a previous message on this list I
> thought this would work (e.g. show "Data coming from myfile.dat")

  Please file a bugreport with testcase for this one.

> 3) it is still unclear to me what happens/should happen if I work with
> two ASCII files which both generate [Line1] strings for instance. I
> obviously can't access both with the same name. Currently, they seem to
> live in separate workspaces and there are no collisions since access
> happens from a vector, which is linked with a datafile (and can access
> only its "own" metadata. If we export the metadata in the global
> variables as required for point 2) above, then there should be a unique
> name generation algorithm somewhere (like for other objects).

   I'm open to suggestions.  Generating a name sounds like an unpredictable 
way to make sessions though.

> 4) related questions are: how can we change a metadata's name, visualize
> its origin, and ensure it is updated along with all the labels that use
> it when a file is reloaded with different data in it

   Can you provide more details on what you mean here?  I think wiping the 
structure in the datasource object should clear out any existing metadata but 
I haven't experimented with this.

> I'd be interested to know whether there are chances to have this in
> 1.3.0 ?

  Roughly 0.1% chance.  1.3.0 is coming out as soon as we can stabilize it.

-- 
George Staikos
KDE Developer				http://www.kde.org/
Staikos Computing Services Inc.		http://www.staikos.net/