Backwards incompatible changes in VOTable 1.2

[Tom McGlynn]

Hi Thomas,

I'd guess the changes were made to support streaming of VOTable responses.  E.g., 
in TAP an INFO element after the table results indicates that the query results 
are incomplete if the query results exceed the user's limit on the number of rows. 
If INFO elements are only allowed at the beginning we can't begin writing results 
until the query is finished.  Supporting streaming seems like a worthy goal, but 
perhaps it could have been done in some more compatible way.  Sebastien's link 
suggests that a new version of the schema standard might resolve the amgibuities 
in the schema in a way that would restore compatibility, but presumably that's not 
likely to happen on a useful time scale.

	Regards,
	Tom

Thomas Boch wrote:
> Hi,
>
> I recenty found out (at my expense) that the VOTable 1.2 schema
> introduced some backwards incompatible changes with respect to earlier
> versions of the standard.
> The following structure :
> <RESOURCE>
>    <INFO name="foo" value="fooValue"></INFO>
>    <INFO name="bar" value="barValue"></INFO>
>    <LINK action="http://mydomain.com/mylink" />
> </RESOURCE>
>
> is valid in VOTable 1.1 but is invalid in VOTable 1.2
>
> It seems that the issue comes from changes made in order to allow INFO
> elements before the closing tags /TABLE, /RESOURCE and /VOTABLE.
> Was there a strong enough use case for introducing a change which breaks
> backwards compatibility ?
> I feel that this incompatibility should be clearly and proeminently
> pointed out in the VOTable document.
>
> Cheers,
>
> Thomas
>