On 2012-10-10, 14:24, Marco Leise wrote:
enum Comparison {
Before = -1,
Same = 0,
After = 1,
Unordered = NaN,
}
a) There is no integer NaN and floating point is a no-go.
The NaN was intended as a joke, and to highlight the fact that
you can have opCmp return a float today, and get some of the
behavior that floats have.
b) If you mix sortable and unsortable most algorithms fail.
Otherwise an enum solution is good, but a bit longer in
code:
auto rel = a.OpCmp(b);
if (rel < 0) ...;
else if (rel > 0) ...;
else ...;
vs.
if (rel == Comparison.Before) ...;
else if (rel == Comparison.After) ...;
else ...;
And in many cases right now you can just "return a - b";
Yeah, this last part is what I really like about the
current solution. Of course, if we could have ranged enums:
enum Comparison {
Before < 0,
Same = 0,
After > 0
}
But that's not going to happen (unless someone provides it
in a library, of course).
--
Simen
