ADQL-2.1 internal draft

[Mark Taylor]

On Thu, 9 Jul 2015, Markus Demleitner wrote:

> Given we copy the funky usage of {}, I'd suggest to add a strong
> 
>   *Note*: The usage of {} in the EBNF in this specification follows the
>   usage in SQL92, i.e., it is used for grouping.  It is *not* used as
>   a zero-or-more operator as frequently done in other kinds of EBNF.

I've got no objection to such an addition, but note that the
EBNF conventions in use by ADQL (including curly brackets)
already are explicitly listed in Section 2, so you can't really
blame the standard text for misunderstandings here :-).

To ensure that readers notice this it might be most effective
to add a note near the full Grammar itself: at the start of
Appendix A and in the preamble of the version at
http://www.ivoa.net/internal/IVOA/IvoaVOQL/adql-bnf-v2.0.html

Mark

--
Mark Taylor   Astronomical Programmer   Physics, Bristol University, UK
m.b.taylor at bris.ac.uk +44-117-9288776  http://www.star.bris.ac.uk/~mbt/