[Interest] QVariant compare operator

[Matthew Woehlke]

On 20/04/2020 12.21, André Pönitz wrote:
> On Mon, Apr 20, 2020 at 10:04:38AM -0400, Matthew Woehlke wrote:
>> On 19/04/2020 08.23, André Pönitz wrote:
>>> QVariant(TypeA) and QVariant(TypeB) can be ordered for different TypeA and
>>> TypeB based e.g. on alphabetical order of their .typeName().
>>>
>>> If wanted, this can be refined to make e.g. all integral types comparable.
>>
>> No:
>>
>>    int{5} <=> JsonObject{...} => lesser
>>    int{5} <=> long{3} => greater
>>    long{3} <=> JsonObject{...} => greater
>>
>> ...oops.
> 
> "make comparable" means lumping them into a common "type", say
> "@integral", with values covering the union set of the values
> of the original type.

...and now your rule for heterogeneous comparisons ***isn't*** 
'according to the type name'. It's 'according to the type name, *except* 
<list of exceptions>'. Yuck.

>> You'd have to make all integral types sort before (or after) all other
>> types, but then you're back to not having a reliable ordering by type name.
> 
> No.

Really? Please explain how this is *not* the case.

-- 
Matthew