TAPRegExt function declaration [was: ADQL polymorphic functions]

[Markus Demleitner]

Dear Grégory,

[restricting to DAL, as this is becoming rather DAL-specific]

On Fri, Apr 23, 2021 at 10:37:03AM +0200, Grégory Mantelet wrote:
>      not the best one.
>      An alternative could be to introduce special types like:
> ANY, ANY_NUMERIC, ...
> 
> About datatypes in UDF signature, for the moment, nothing specifies what
> datatypes are allowed. And this is especially the case in ADQL, where there
> is
> no strong typing.
> 
> Personally, when reading such datatypes, my ADQL parser simplifies them as
> "numeric", "string", "geometry" and "unknown" (a synonym of "any") in order
> to
> check types ; it allows it to make a simple query check with approximate

You know -- shouldn't we just adopt this as the recommended type
system (with "any" instead of "unknown")?  I *think* that's covering
the use cases we have for the signatures, and it's nice and simple.

I'd totally support an issue to this effect against
https://github.com/ivoa-std/TAPRegExt.  I'd even write a PR unless
you want to.

Thanks,

        Markus