Regex Tester & Validator

A pragmatic email validator built from chained lookaheads: it requires exactly one @, restricts both local part and domain to alphanumerics, dots, plus signs and hyphens (via a subroutine call to group 1), mandates a trailing alphabetic TLD (blocking numeric endings like .123), forbids consecutive dots, and disallows punctuation at the string start or immediately adjacent to the @. Since it ends with .*, the full line matches only when all checks pass, making it suitable for line-by-line email screening.