PR-TAP-1.1 - Some comments
m.b.taylor at bristol.ac.uk
Mon Sep 11 23:54:42 CEST 2017
As far as I can see: there is no definite answer to that question.
I can't find any ruling on it in standards text, and it seems
that implementations have taken different lines on it.
On Mon, 11 Sep 2017, Patrick Dowler wrote:
> So just to be clear: the interpretation of arraysize="1" vs null (in
> tap_schema) or missing (in a VOtable) isn't just cosmetic because
> null/missing means a scalar and 1 means an array?
> I never thought about that detail much and I guess assumed it was more
> like the database treatment than the resulting datatype (int vs int)
> in software.
> On 8 September 2017 at 05:01, Mark Taylor <m.b.taylor at bristol.ac.uk> wrote:
> > On Fri, 8 Sep 2017, Markus Demleitner wrote:
> >> Dear DAL,
> >> On Fri, Sep 08, 2017 at 11:42:49AM +0100, Mark Taylor wrote:
> >> > I always thought that in VOTable (following FITS practice),
> >> > setting the arraysize attribute to "1" has an identical meaning
> >> > to omitting it, i.e. that VOTable makes no distinction between
> >> > a scalar and a single-element array. However now that I look
> >> > I can't find that confirmed (or denied) in the VOTable specification.
> >> Hmha -- I think the fact that TOPCAT/stilts and astropy, certainly
> > [I didn't realise astropy did that differently]
> >> among the two most widespread consumers of VOTables out there,
> >> disagree on that point is a strong indication that we need to clean
> >> this up.
> > ... but it also means that cleaning it up would be pretty difficult
> > to do. If we decree that one or the other interpretation is correct,
> > it means one or the other popular software item ought to change its
> > behaviour in a probably backwardly-incompatible way.
> >> Anyone in for writing an Erratum?
> > So, no, since I don't know what it would say.
> > --
> > 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/
> Patrick Dowler
> Canadian Astronomy Data Centre
> Victoria, BC, Canada
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/
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