Re: range_adjacent and discrete ranges

Florian Pflug <fgp@phlo.org> writes:
> ...This definition does not depend on any specific canonical form of ranges,
> only on the canonicalize function's ability to detect empty ranges.

Hmm, well, now that you mention it, I don't think the current canonical
functions handle empty ranges very nicely at all.  They tend to spit up:

regression=# select int4range(4,4,'[]');
 int4range 
-----------
 [4,5)
(1 row)

regression=# select int4range(4,4,'(]');
ERROR:  range lower bound must be less than or equal to range upper bound
regression=# select int4range(4,4,'()');
ERROR:  range lower bound must be less than or equal to range upper bound

Would it be better for them to silently transform such cases to "empty"?

			regards, tom lane