Re: VARIANT / ANYTYPE datatype

On Tue, May 10, 2011 at 10:29 PM, Joseph Adams
<joeyadams3(dot)14159(at)gmail(dot)com> wrote:
> The VARIANT type, or similar, would be useful for the JSON data type
> I've been intermittently working on, as it would allow us to create a
> function like this:
>
>    from_json(JSON) returns VARIANT

This occurred to me: if PostgreSQL functions could return ANYELEMENT,
then we could just say:

from_json(JSON) returns ANYELEMENT -- no intermediate VARIANT value

Likewise, the variant conversion functions (which could be invoked
automatically) could be done this way:

to_variant(ANYELEMENT) returns VARIANT
from_variant(VARIANT) returns ANYELEMENT

However, I'm not familiar enough with the innards of PostgreSQL's type
system to know if returning ANYELEMENT would be possible and make
sense.