# returns Fizz if n is divisible by 3,
#         Buzz if n is divisible by 5,
#         FizzBuzz if n is divisible by 3 and 5,
#         n as a string otherwise
def fizzbuzz(n)
    if =(+(mod(n 3) mod(n 5)) 0)
        "FizzBuzz"
    elif =(mod(n 3) 0)
        "Fizz"
    elif =(mod(n 5) 0)
        "Buzz"
    else
        string(n)
    end
end

# generate a list of integers from n to top
def genlist(n top)
    def rec(l n top)
        if <=(n top)
            @rec(+(l list(n)) +(n 1) top)
        else
            l
        end
    end
    rec(list() n top)
end

def main()
    display(map(fizzbuzz genlist(1 20)))
end