> On 14 Mar 2024, at 20:10, Peter Eisentraut <pe...@eisentraut.org> wrote:
>
>>>>> I think the behavior of uuid_extract_var(iant) is wrong. The code
>>>>> takes just two bits to return, but the draft document is quite clear
>>>>> that the variant is 4 bits (see Table 1).
>>>> Well, it was correct only for implemented variant. I've made version that
>>>> implements full table 1 from section 4.1.
>>> I think we are still interpreting this differently. I think
>>> uuid_extract_variant should just return whatever is in those four bits.
>>> Your function comment says "Can return only 0, 0b10, 0b110 and 0b111.",
>>> which I don't think it is correct. It should return 0 through 15.
>> We will return "do not care" bits. This bits can confuse someone. E.g. for
>> varaint 0b10 we can return 8, 9, 10 and 11 randomly. Is it OK? BTW for some
>> reason document lists number 1-15, but your are correct that range is 0-15.
>
> I agree it's confusing. Before I studied the RFC 4122bis project, I didn't
> even know about variant vs. version. I think overall people will find this
> more confusing than useful. If you just want to know, "is this UUID of the
> kind specified in RFC 4122", you can query it with uuid_extract_version(x) IS
> NOT NULL. So maybe we don't need the _extract_variant function?
I think it's the best possible solution. The variant has no value besides
detecting if a version can be extracted.
Best regards, Andrey Borodin.
