ADQL-2.1 Working Draft available on the repo

[Ger van Diepen]

Hi Walter, 

Thanks for your explanation. 
I understand, although I think an error message like "name 'abc' is not
defined" (as Python will give) will be just as clear. 

But note it is not possible to make every function a reserved ADQL
keyword, certainly not for UDFs and (to assure backward compatibility)
for functions added at a later stage. I certainly hope that parsers
won't rely on function names being reserved keywords. 

Cheers, 
Ger

>>> Walter Landry <wlandry at caltech.edu> 5/9/2016 3:33 PM >>>
Making them reserved improves error detection.  If someone writes

  10*abs*C

rather than

  10*abs(C)

then I can give a descriptive error at parse time

  On line XXX, column YYY, expected '(', found '*'

rather than running the query through the database backend and hoping
that the database generates a decent error message.

Cheers,
Walter Landry

Marco Molinaro <molinaro at oats.inaf.it> wrote:
> Dear Ger,
> I forward your enquiry to the DAL mailing list, being this of
interest
> to the full community.
>
> I have, personally, not a strong opinion on this.
>
> The reserved ABS keyword, together with other ones referring to
> functions in ADQL, comes from the initial ADQL specification, now
> under revision.
> So the answer can be as simple as the second paragraph in $2.1.2 of
> the spec (refer to either 2.0 or 2.1 version): special meaning and
> escaping solution in place.
>
> I let the other ADQL experts comment deeper on the topic.
>
> Cheers,
>     Marco
>
> ---------- Forwarded message ----------
> Subject: Re: ADQL-2.1 Working Draft available on the repo
>
>
> Hi Marco,
>
>
> I'm a bit surprised to see that function names like ABS are reserved
> ADQL keywords. A parser does not need it to distinguish between
> function names and identifiers. So why is that?
>
>
> Cheers,
>
> Ger van Diepen
>
>
>
>>>> Marco Molinaro <molinaro at oats.inaf.it> 5/3/2016 11:32 AM >>>
>
>
> Dear all,
> is now available in the IVOA Document Repository
> the Working Draft for the ADQL-2.1 specification:
>
> http://www.ivoa.net/documents/ADQL/20160502/
>
> (PDF and HTML format there, plus volute source)
> The WD will be presented with current updates at
> the oncoming Interop in Cape Town (DAL 1, next Tuesday).
> Comments and discussions are welcome there as well
> as on the DAL mailing list.
>
> Cheers
>      François & Marco (your DAL chair and vice) and Dave (the
editor)
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