MattK

Unfortunately, you can't use a regular expression to check for every palindrome. This is because the "language of palindromes" isn't a regular language.

You should be able to read more about this in a textbook that covers formal language theory. This includes a lot of textbooks which cover parsing and compilation.

I feel that functional languages haven't been well represented. This is Scheme code:

(define (palindrome? s)
  (define (iter s)
    (cond ((equal? (length s) 0) #t)
          ((equal? (length s) 1) #t)
          ((equal? (car s) (car (reverse s)))
           (iter (reverse (cdr (reverse (cdr s))))))
          (else #f)))
  (iter (string->list s)))

Feel the elegance =)