[inanutshellus]

Haha, I debated about throwing in the multi-dot address. Bummed that it was a bad example. :(

As for parens, I recollect the spec lets you nest your parens and quotes! It's insane. e.g. `f(oo."(bar."baz")."quux)@example.com` is valid in the spec.

I wrote an Oracle regex to parse for valid email addresses and I went against the spec rather than what is what's practically used. It was an insane thing.