Why Strings as Classes?

[Yigal Chripun]

Benji suggested run-time inheritance and at least from a design
perspective I like some of his thoughts.
I've got a few questions though:

a) people here said that a virtual call will make it slow. How much
slow? how much of an overhead is it on modern hardware considering also
that this is a place where hardware manufacturers spend time on
optimizations?

b) can't a string class use implicit casts and maybe some sugar to
pretend to be a regular array in such a way to avoid that virtual call
and still be useful?
you already can do array.func(...) instead of func(array, ...) so this
can be used with a string class that implicitly converts to a char array..

C) compile-time interfaces? (aka concepts)