Re: Range types

Scott Bailey <artacus@comcast.net> writes:
> Because intervals (mathematical not SQL) can be open or closed at each 
> end point we need to know what the next an previous value would be at 
> the specified granularity. And while you can do some operations without 
> knowing this, there are many you can't. For instance you could not tell 
> whether two [] or () ranges were adjacent, or be able to coalesce an 
> array of ranges.

This statement seems to me to demonstrate that you don't actually
understand the concept of open and closed ranges.  It has nothing
whatsoever to do with assuming that the data type is discrete;
these concepts are perfectly well defined for the reals, for example.
What it is about is whether the inclusion conditions are "< bound"
or "<= bound".
        regards, tom lane