opCmp, [partial/total/pre]orders, custom floating point types etc.

[Fool via Digitalmars-d]

On Tuesday, 12 January 2016 at 19:48:35 UTC, Fool wrote:
> On Tuesday, 12 January 2016 at 19:46:47 UTC, John Colvin wrote:
>> On Tuesday, 12 January 2016 at 19:44:18 UTC, Fool wrote:
>>> Non-reflexive '<=' does not make any sense at all.
>>
>> It might be a bit of a mess, agreed, but nonetheless:
>>
>> assert(!(float.nan <= float.nan));
>
> Agreed, but in case of float '<=' is not an order at all.

By the way, that implies that the result of sorting an array of 
float by default comparison is undefined unless the array does 
not contain NaN.