Sean Lange (9/2/2014)
Nadrek (9/2/2014)
Which has a sample Perl RegEx for RFC822 validation, NOT including the arbitrarily nested comments allowed by the RFC.
Heaven help you if you have to debug that thing. That to me does not look like a viable piece of code I would put anywhere near my system. That whole being able to support my code thing comes to mind. 😛
Judging by RFC822, no accurate 'validate email' code is going to be viable or supportable except by a domain expert :w00t:.