content: to rot13(textString)
    local outChars
    set outChars to {}
    repeat with ch in (characters of textString)
      if (ch >= "a" and ch <= "m") or (ch >= "A" and ch <= "M") then
        set ch to character id (id of ch + 13)
      else if (ch >= "n" and ch <= "z") or (ch >= "N" and ch <= "Z") then
        set ch to character id (id of ch - 13)
      end
      set end of outChars to ch
    end
    return outChars as text
  end rot13
  