3.1.2. Complete Expression for Deliverable Email Address

The following regular expression is a deliverable email address:

; Mailbox from RFC 5321, as amended

P E J DEA     = ([A-Za-z0-9!#-'*+\-/=?^_`{-~\xA0-\x{10FFFF}]+
(?:\.[A-Za-z0-9!#-'*+\-/=?^_`{-~\xA0-\x{10FFFF}])|
"(?:[ !#-\[\]-~\xA0-\x{10FFFF}]|\\[ -~])*")@
((?:[A-Za-z0-9](https:///?:[A-Za-z0-9\-]*[A-Za-z0-9])?|
[\x00-\x{10FFFF}]*[\x80-\x{10FFFF}]+[\x00-\x{10FFFF}]*)
(?:\.(?:[A-Za-z0-9](https:///?:[A-Za-z0-9\-]*
[A-Za-z0-9])?|[\x00-\x{10FFFF}]*
[\x80-\x{10FFFF}]+[\x00-\x{10FFFF}]*))*)

In the regular expression DEA, capturing group 1 is the local-part
production, and capturing group 2 is the domain production.