Re: array_length()

Pavel Stehule wrote:
> Hello
> 
> 2008/11/5 Peter Eisentraut <peter_e@gmx.net>:
>> Decibel! wrote:
>>> ISTM it'd be useful to have an array_length function (since I just wrote
>>> one for work ;), so here's a patch. Note that I don't have the docs
>>> toolchain setup, so I wasn't able to test the doc patches.
>> There is a tiny problem with this implementation: It returns null for an
>> empty array, not zero.  This is because array_lower and/or array_upper
>> return null for an empty array, which makes sense for those cases.  We could
>> fix this by putting a coalesce around the expression, but since the array
>> functions return null for all kinds of error cases, this might mask other
>> problems.  Or we move to a C implementation.
>>
> 
> we should to write function isempty(anyarray), that returns true when
> param is empty.

Well, isn't isempty() just a special case of array_length()?  One or the 
other needs to be implemented, so we might as well go for the general 
case, IMO.