On Tuesday, 12 January 2016 at 21:27:38 UTC, Timon Gehr wrote:
On 01/12/2016 10:02 PM, John Colvin wrote:
On Tuesday, 12 January 2016 at 20:52:51 UTC, Timon Gehr wrote:
On 01/12/2016 07:27 PM, John Colvin wrote:
...
struct S{
auto opCmp(S rhs){ return float.nan; }
bool opEquals(S rhs){ return false; }
}
unittest{
S a,b;
assert(!(a==b));
assert(!(a<b));
assert(!(a<=b));
assert(!(a>b));
assert(!(a>=b));
}
what about classes and Object.opCmp?
You can introduce a new opCmp signature in your subclass, but
== is enforced to be reflexive for class objects. So this
approach only really works for structs. (And for structs, it is
obviously a hack.)
I actually quite like it. Also, checking the generated assembly
for an IntWithNaN type: no floating point comparisons in sight
(with gdc and ldc at least, don't really care if dmd does
something a bit dumb)