Swift code to check if a string is a palindrome

palindrome.swift

func isPalindrome(sequence: String) -> Bool {
  // Start the indexes at the beginning and ending of the string
  var findex = sequence.startIndex;
  var bindex = sequence.index(before: sequence.endIndex);
  
  // While they don't meet, check if the characters match
  while findex < bindex {
    if sequence[findex] != sequence[bindex] {
      return false
    }

    // Since we're not comparing whitespace, we need to skip over any of them
    repeat {
      findex = sequence.index(after: findex)
    } while sequence[findex].isWhitespace

    repeat {
      bindex = sequence.index(before: bindex)
    } while sequence[bindex].isWhitespace
  }

  return true
}