AA with complex keytype?

[Manfred Nowak]

Frits van Bommel wrote
> As long as the order is consistent[1] (a < b && b <
> c => a < c, that sort of thing) they're happy.

Thank you. This answers my question.

But immediately another arises:
Why are classes required to implement opCmp( Object) for AA's to 
function properly?

Currently AA's misbehave if opCmp(Object) is not overwritten for a 
class, but no error is thrown.

For the transitivity of an ordering it suffices for opCmp(Object) to 
always give "==" if the objects are equal, and give "<" if they are 
not.

It should be easy to implement this as the default opCmp(Object).