sequence alpha_b = repeat(0,255)
         alpha_b['A'..'Z'] = 'A'
         alpha_b['a'..'z'] = 'a'

function caesar(string s, integer key)
integer ch, base
    for i=1 to length(s) do
        ch = s[i]
        base = alpha_b[ch]
        if base then
            s[i] = base+remainder(ch-base+key,26)
        end if
    end for
    return s
end function
string s = "One fine day in the middle of the night, two dead men got up to fight. \n"&
           "Back to back they faced each other, drew their swords and shot each other. %^&*()[",
       e = caesar(s,5),
       r = caesar(e,26-5)  ?e ?r