[Haskell-beginners] Longest palindrome

Hi Café. I've been looking at implementing the following algorithm in haskell. Take the maximum length palindrome from the list of palindromes generated from the original list by: Taking each element as a starting point, then expanding either side while the string is still a palindrome. I could do this numerically after generating an array from a list, but I was wondering if there was a more idiomatic way to go about it.