struct opCmp?
Christopher Wright
dhasenan at gmail.com
Fri May 15 04:06:01 PDT 2009
Frits van Bommel wrote:
> Nick Sabalausky wrote:
>> Can anyone think of a reasonable case where it would actually make
>> sense to override opCmp, but not opEquals? (that is, without
>> bastardizing them like in a "C++ streams" kind of way)
>
> How about a struct you want to be opCmp()-comparable (which, according
> to the spec, they aren't by default), but for which equality means
> bitwise-equality?
>
> Similarly, a class that's uniqued (so there are no equal instances that
> aren't actually the same instance, i.e. comparison means
> pointer-comparison), yet that has some kind of natural ordering
> implemented through opCmp().
In these cases, you can override opEquals to do the bitwise comparisons
or pointer comparisons. They're relatively rare, I think.
And that natural ordering has to be a total ordering.
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