From http://www.ex-parrot.com/pdw/Mail-RFC822-Address.html http://www.ex-parrot.com/pdw/Mail-RFC822-Address.html: Mail::RFC822::Address is a Perl module to val

From http://www.ex-parrot.com/pdw/Mail-RFC822-Address.html http://www.ex-parrot.com/pdw/Mail-RFC822-Address.html: Mail::RFC822::Address is a Perl module to validate email addresses according to the RFC 822 grammar. (...) Implementing validation with regular expressions somewhat pushes the limits of what it is sensible to do with regular expressions, although Perl copes well: (?:(?:\r\n)?[ \t])*(?:(?:(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t] )+|\Z|(?=[\["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))*"(?:(?: \r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:( ?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))*"(?:(?:\r\n)?[ \t])*))*@(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".\[\] \000-\0 ** SNIP: 76 lines ** ?:\r\n)?[ \t])*))*)?;\s*)