3 ms·
Have a read of RFC 2822[1] section 3.4 In brief, the address specification may look like the simple "local" @ "domain", but those subparts can be non-regular (
by Xophmeister 12y ago
Have a read of RFC 2822[1] section 3.4
In brief, the address specification may look like the simple "local" @ "domain", but those subparts can be non-regular (i.e., making them hard/impossible for a regular expression engine to parse) or contain a lot of exceptions (e.g., the domain could be google.com, or it could be 12.34.56.78, or localhost, or a number of other things).
[1] https://www.ietf.org/rfc/rfc2822.txt https://www.ietf.org/rfc/rfc2822.txt