Thank you for the peek into the upcoming Exegesis.
...which is now fully on-line.
But I wanted to note that equalness of two undefs is very useful but contradicts with generally accepted laws of three-state logic, does it not?
It sure does. There was a long discussion around that issue on the perl6-language mailing list...starting
here.
As I recall, there wasn't a clear outcome to the debate (surprise, surprise), but at the time Larry didn't seem keen on undef taking on the tri-state semantics of NULL.