Re: Initial review of xslt with no limits patch

"David E. Wheeler" <david@kineticode.com> writes:
> I think that some sort of variadic pairs would be useful for this. But since there is no core "ordered pair" data type, I don't think you're going to get too far.

It's not immediately clear to me what an ordered-pair type would get you
that you don't get with 2-element arrays.

A couple of quick experiments suggest that 2-D arrays might be the thing
to use.  They're easy to construct:

regression=# select array[[1,2],[3,4]];
     array     
---------------
 {{1,2},{3,4}}
(1 row)

and you can build them dynamically at need:

regression=# select array[[1,2],[3,4]] || array[5,6];
      ?column?       
---------------------
 {{1,2},{3,4},{5,6}}
(1 row)

This is not exactly without precedent, either: our built-in xpath()
function appears to use precisely this approach for its namespace-list
argument.

			regards, tom lane