Re: array_length(anyarray)

On Thu, Jan 9, 2014 at 11:08 AM, Marko Tiikkaja <marko(at)joh(dot)to> wrote:
> On 1/9/14 5:44 PM, Florian Pflug wrote:
>>
>> On Jan9, 2014, at 14:57 , Dean Rasheed <dean(dot)a(dot)rasheed(at)gmail(dot)com> wrote:
>>>
>>> On 19 December 2013 08:05, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> wrote:
>>>>
>>>> length should be irrelevant to fact so array starts from 1, 0 or
>>>> anything
>>>> else
>>>
>>>
>>> Yes, this should just return the number of elements, and 0 for an empty
>>> array.
>>
>>
>> +1. Anything that complains about arrays whose lower bound isn't 1 really
>> needs a *way* less generic name than array_length().
>
>
> Problem is, if you're operating on an array which could have a lower bound
> that isn't 1, why would you look at the length in the first place? You
> can't access any elements by index, you'd need to look at array_lower().
> You can't iterate over the array by index, you'd need to do array_lower()
> .. array_lower() + array_length(), which doesn't make sense. And then
> there's the myriad of stuff you can do with unnest() without actually having
> to look at the length. Same goes for multi-dimensional arrays: you have
> even less things you can do there with only a length.

I'm piling on: it's not clear at all to me why you've special cased
this to lower_bound=1. First of all, there are other reasons to check
length than iteration. If you want your code to blow up with non 1
based array, that should be checked in userland I think (perhaps with
a constraint); the server API function should implement as many
reasonable behaviors as possible.

merlin