ProtoObject and comparison for equality and ordering

[Seb]

On Tuesday, 14 May 2019 at 21:06:05 UTC, Mike Franklin wrote:
> On Tuesday, 14 May 2019 at 20:36:08 UTC, Eduard Staniloiu wrote:
>
>> Should `opCmp` return a float?
>>
>> The reason: when we attempt to compare two types that aren't 
>> comparable (an unordered relationship) we can return 
>> float.NaN. Thus we can differentiate between a valid -1, 0, 1 
>> and an invalid float.NaN comparison.
>
> Seems like a job for an enum, not a float or an integer.
>
> Mike

+1 for enum. As far as I can see you only have four actual states:

lower, equal, higher, nonComparable