On Thursday 08 April 2004 12:50 pm, Francois Ochsenbein wrote:
> > * re 3.5: LINK
> > in what way are parsers expected to 'understand' the 'three common
> > protocols'? What is the parser expected to do with the object at the
> > end of the link? Eg, does it embed the data in the element being
> > parsed, shell out to a browser etc?
>
> The parser does not do any action -- that's the role of the application.
> But the parser has to retrieve this links so that the application
> software is able to retrieve the linked data.
The difference between parser and application here is blurred if the parser is anything other than the standard java parser implementations. At this level we should be describing what goes into the link, it is then up to the parser/application implementation to handle it.
> > * re 4.3: unit
> > are the unit values enumerated under some schema? how are they
> > validated?
>
> Full references are given. There is java (or C) code which can make
> this test. Too complex for XSD, the number of possible combinations
> can be huge.
I agree that the units should not go into the *VOTable* schema, but I am beginning to think we could do with defining a Units schema (probably based on the CDS list at http://vizier.u-strasbg.fr/cgi-bin/Unit?%3f). This would enumerate all standard units and a way of including specials, and then this schema can be 'imported' to the VOTable schema. I don't suggest this for v1.1, but as a separate bit of work for us to include in v1.1.1 (or 1.2, or whatever the current versioning sequence is!)
> > * re 4.6: MIN/MAX & OPTION
> > is it valid to have both MIN/MAX and OPTION? Schema allows both.
>
> I agree, it looks strange to have MIN MAX and OPTION -- how would
> this restriction be written in XSD ?
I think there is a clever way of doing it, but a more explicit straightforward way is just to use a wrapping element around MIN/MAX and use choice, ie:
<xs:choice maxOccurs="1">
<xs:element name="Option" type="xs:string"/>
<xs:element name="Range">
<xs:complexType>
<xs:sequence>
<xs:element name="Min" maxOccurs="1" minOccurs="1" type="xs:string"/>
<xs:element name="Max" maxOccurs="1" minOccurs="1" type="xs:string"/>
</xs:sequence>
Cheers,
Martin
-- Martin Hill Astrogrid/AVO, ROE Tel: 07901 55 24 66Received on 2004-04-08Z19:07:57