Mike has already answered most of the questions, but left me the hard
ones.  I'll have a shot at them...

> - why is sorting defined on XPaths?

Mostly because it was an easy, existing specification to use to specify a
path to some data in a structured document.

This doesn't mean that the server has to actually -do- XPath, just that it
should accept them and respond appropriately.  For example, if you can
sort by exact title, author and date, then you might hard wire
/record/title, /record/creator and /record/date to these sort routines.

Then you could just respond with unsupported tag path to all other
requests.

> What I expect to have to do is:  + retrieve every record + convert them
> to adlibXML + translate to the right schema using an XSL + call the
> XPath on each record + sort on the outcome if this XPath

If you want to have any sort supported then this is indeed what you would
have to do, but as above you don't have to support everything.

> possible within the SRW standard to just supply an indexname (which in
> Adlib as well as in relational databases systems is searchable as well
> as sortable..) in stead of the XPath?

Yes.  Define yourself a record schema. Then have the indexnames as
elements within the record schema.
For example, if you want to do:  select * from db order by foo, then you
might want to define an 'adlibSortSchema' with paths:

/adlib/foo
/adlib/bar
/adlib/baz

You just need to then publish what /adlib/... mean.

> - is there an Open Source SRU/SRW tester (like
> http://oai.dlib.vt.edu/cgi-bin/Explorer/oai2.0/testoai for OAI) or a

Not yet, but it's on my list of things to do.

> - the ZeeRex documentation is a bit concise on configInfo. What settings
> exactly are 'setting', 'default' and 'supports'?

setting:  Something which cannot be changed.  You might have a setting of
'maximumRecords' -- the maximum records you can retrieve at once.

default:  Something which can be changed but has a default value.  For
example 'retrievalSchema' -- the default schema you'll get your records in
unless you specify one.

supports:  Some feature of the protocol which the server supports.  For
example sorting, proximity of the scan operation.

> And why would you want to have a default stylesheet? That disables XML
> retrieval altogether, or do I misinterpret something?

The stylesheet is -not- one to be applied to the data, but instead just to
be included in the header of the data.

For example:

<?xml version="1.0"?>
<?xml-stylesheet href="http://foo.bar.baz/style.xsl"?>
<srw:searchRetrieveRequest>
  ...

Rather than applying foo.bar.baz/style.xsl to the data and then returning
the transformed record.

Hope this helps, if it doesn't please feel free to ask again :)

Rob




       ,'/:.          Dr Robert Sanderson ([log in to unmask])
     ,'-/::::.        http://www.o-r-g.org/~azaroth/
   ,'--/::(@)::.      Dept. of Computer Science, Room 805
,'---/::::::::::.    University of Liverpool
____/:::::::::::::.  L5R Shop: http://www.cardsnotwords.com/
I L L U M I N A T I