<INFO> tag in VOTable1.2
dtody at nrao.edu
Wed Mar 4 11:03:03 PST 2009
On Wed, 4 Mar 2009, Mark Taylor wrote:
>> For the implementors who want to be compatible with the
>> 2 versions (1.1 and 1.2) it means in practice accept
>> a text embedded within <INFO> and </INFO> as if it were
>> surrounded by the <DESCRIPTION> and </DESCRIPTION> tags.
>> Do you feel this is a big source of trouble, or improving
>> the VOTable documentation could be a viable solution ?
> Like I've said, I'll do it if there's a good reason to
> (I've already likely spent longer arguing about it than it would
> take to make the implementation changes).
> But if the change is poorly justified or even makes things worse then
> I don't think it should be adopted into the standard.
> VOTable is a widely used standard within the VO. It's already
> become clear that the change to INFO causes complications for TAP
> (http://www.ivoa.net/forum/dal/0902/1012.htm), and there will
> probably be others. If we want to make changes there should be
> a robust justification for them. I haven't yet seen one for this
The problem is not just TAP, but all the DAL interfaces since INFO
is used to return the status of a service operation. This especially
affects the existing standards and implementations since these contain
explicit examples showing the use of INFO, based upon VOTable 1.1.
The problem is not the technical details of the change to INFO in
1.2, which I might even agree with, rather that the changes are not
backwards compatible, possibly causing existing software to break.
That said, the problem is not as serious as I at first thought as only
the descriptive text is affected. The most critical tags affecting
INFO use in DAL are NAME and VALUE which do not appear to have changed.
The descriptive text is merely informative. An existing application
written for VOTable 1.1, presented with data encoded as VOTable 1.2
(and not noticing the version change) would probably work although
the descriptive text would likely be lost.
> Finally you are right -- discussions take much more time
> than adapting the code of our applications :-).
Maybe so, but it may take quite a while for the whole world to upgrade.
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