Re: range_agg

> > Btw I have working multirange_{send,recv,in,out} now. . . .

Just about all the other operators are done too, but I wonder what
symbols people like for union and minus? Range uses + for union. I
have working code and tests that adds this:

r + mr = mr
mr + r = mr
mr + mr = mr

But I would like to use a different symbol instead, like ++, so I can
have all four:

r ++ r = mr
r ++ mr = mr
mr ++ r = mr
mr ++ mr = mr

(The existing r + r operator throws an error if the inputs have a gap.)

The trouble is that ++ isn't allowed. (Neither is --.) From
https://www.postgresql.org/docs/11/sql-createoperator.html :

> A multicharacter operator name cannot end in + or -, unless the name also contains at least one of these characters:
> ~ ! @ # % ^ & | ` ?

So are there any other suggestions? I'm open to arguments that I
should just use +, but I think having a way to add two simple ranges
and get a multirange would be nice too, so my preference is to find a
new operator. It should work with minus and intersection (* for
ranges) too. Some proposals:

+* and -* and ** (* as in regex "zero or many" reminds me of how a
multirange holds zero or many ranges. ** is confusing though because
it's like exponentiation.)

@+ and @- and @* (I dunno why but I kind of like it. We already have @> and <@.)

<+> and <-> and <*> (I was hoping for (+) etc for the math connection
to circled operators, but this is close. Maybe this would be stronger
if multirange_{in,out} used <> delims instead of {}, although I also
like how {} is consistent with arrays.)

Anyone else have any thoughts?

Thanks,
Paul