ADQL-2.1 internal draft

[Marco Molinaro]

Hi Mark, hi all,

I fixed what's not answered here and tried to clarify a bit the references
(but there's still some work to do for the bibrefs).

2015-06-22 13:41 GMT+02:00 Mark Taylor <m.b.taylor at bristol.ac.uk>:
> Sec 2.1.2:
>
>    The syntax quoted here:
>
>       "<Latin_letter> [{ <underscore> | {<Latin_letter> | <digit>} }]"
>
>    seems to be missing at least one ellipsis, compared to that in
>    the BNF in Appendix A.  By my reading the above syntax limits
>    identifiers to two characters.  This text hasn't changed since
>    ADQL v2.0 though, so if this is an error it's not new in this version.

I changed it accordingly to the BNF in appendix, I agree with you the
above read as two characters only.

> Sec 2.3:
>
>    Like Walter, I don't really undertand rand(x) - as far as I can see
>    since it takes a seed it would be determinstic, which isn't
>    very useful.  Am I missing something?

I wonder if this is just another errata...i.e. it could be considered
implicit the idea of having a null seed.
In my experience, however, I found implementations of rand that actually
required a seed (letting, e.g., be the milliseconds of the computer internal
timer to rule the randomness) ...probably not so clever, it turns out to be a
pseudo-random generator.

My guess is that we can change the description explicitly letting x be null
or even letting x be omitted, if we go the "overload" way it seems we are
already facing for geometric functions.
What do DAL people think of this?

> Sec 4.2.18:
>
>     There should be some discussion of permitted/recommended behaviour
>     in the case that a non-empty string is submitted as the first
>     argument of one of the geometry functions.

I think this is yet under discussion.
Probably better to wait for agreement on how to proceed (empty string
vs. overload)
before changing this.

I (probably today or tomorrow) add and ADQL-2.0-Next page to the wiki to report
what has been discussed in Sesto (freely using also Dave's notes :) )

Cheers,
    Marco