SODA Gripes (5) No single-value arguments for intervals

[Markus Demleitner]

Hi James,

On Thu, Mar 03, 2016 at 09:57:40PM +0000, James.Dempsey at csiro.au wrote:
> I'm not sure if my post on this reached the list, but I still have
> the concern that we should maintain consistency between the same
> parameters for SIA2 and SODA where possible.

I agree we should not have special rules in protocols, but in this
case I'd say SIAv2 is the oddball, at least relative to current DALI
drafts.

I had mildly protested these single-value "intervals" (e.g., a
mail to dal at ivoa.net from 28 Aug 2015 that interestingly didn't make
it to the archives -- hm):

  [...]

  I'd finally like to register my reservations to the idea that single
  values can be passed into double[2]/xtype=INTERVAL-typed parameters,
  as we're again lying about types, which will fall on our feet[1]
  while, as far as I can see, not adding any functionality. But that's
  just for the record and *not* arguing against this going forward.

  Let's tackle server-side processing ("Accessdata") now!

  Cheers,

          Markus

  [1] I'd argue it already is on the way to hit a toe.  If I read

    Find data that includes 21cm:

    BAND=0.21

    The scalar value 550, equivalent to [550,550]:

    BAND=550

  (p. 14), I get a little confused -- is BAND=0.21 equivalent to
  [0.21, 0.21]?  And if it is, why isn't it stated there while it's
  pointed out for BAND=550?  Fortunately, there's the next paragraph
  properly explaining things, but that part then leaves one wondering
  why one would not simply write 550 550 instead of 550 and save all
  the extra words and code...

I stand by that now (with the qualification that arraysize="2*" means
we don't really lie about types, ok) and would propose to fix this in
SIAPv2's next version and have consistency in that way.

Cheers,

        Markus