Posted by John Dunlop on 10/13/06 15:12

Jerry Stuckle:

> I did see a regex which would handle all possible addresses. Don't
> remember where I saw it off hand, but it was around 6500 chars long.

To give a rough idea to anyone who thinks it's easy, Jerry, point your
browser here:

http://www.ex-parrot.com/~pdw/Mail-RFC822-Address.html

That regular expression purportedly validates the well-formedness of
RFC822 e-mail addresses excluding comments. In other words even that
monster couldn't validate e-mail addresses itself. Since RFC2822
obsoleted RFC822, the pattern would need to be even larger, because
RFC2822 allows obsolete productions from RFC822 as well as its own.

> Obviously it's not easy to validate email addresses!

Not half.

(Slightly pedantic, but validating e-mail addresses and validating
e-mail address syntax are two different things. Validating e-mail
addresses entails dicovering if the e-mail address is in use;
validating e-mail address syntax entails checking that the syntax
matches that allowed by RFC2822. Go on, witty retort: 'you're not
being pedantic; you're being pernickety'.)

Enjoy the weekend!

--
Jock

[Back to original message]