Re: Range Types - typo + NULL string constructor

On Tue, Oct 11, 2011 at 12:30 PM, Jeff Davis <pgsql@j-davis.com> wrote:
> On Tue, 2011-10-11 at 12:09 -0400, Robert Haas wrote:
>> The cure seems worse than the disease.  What is so bad about '[]'?
>
> OK, so we stick with the 3-argument form. Do we have a default for the
> third argument, or do we scrap it to avoid confusion?
>
> There were some fairly strong objections to using '[]' as the default or
> having the default vary between types. So, the only real option
> remaining, if we do have a default, is '[)'.

I think using '[)' is fine.  At some level, this is just a question of
expectations.  If you expect that int4range(1,4) will create a range
that includes 4, well, you're wrong.  Once you get used to it, it will
seem normal, and you'll know that you need to write
int4range(1,4,'[]') if that's what you want.  As long as the system is
designed around a set of consistent and well-thought-out principles,
people will get used to the details.  I don't see that the idea of a
half-open range over a discrete-valued type is particularly confusing
- we use them all the time in programming, when we make the end
pointer point to the byte following the end of the array, rather than
the last element - but even if it is, overall design consistency
trumps what someone may find to be the absolutely perfect behavior in
some particular case.  And saving typing is nearly always good -
unless it creates a LOT more confusion than I think this will.

-- 
Robert Haas
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