> it means, so we must not implement any new operator?
If the operator were called %@==+!, I think you could make a good
argument that no one else is likely using that for anything.
Surely the same cannot be said of =>
Of course, %@==+! is not a very convenient name for an operator, but
that's exactly the point: there are only a limited number of good,
short names for operators, and => must be near the top of that list.
...Robert