program fibonacci_words;
    print("N    Length     Entropy");
    print("---- ---------- -------------------");
    loop for n in [1..37] do
        [zeroes, ones] := fibword := fib_word n;
        length := zeroes + ones;
        print(lpad(str n,4) + " " + lpad(str length,10) + " " + str entropy fibword);
    end loop;

    $ Return the amount of zeroes and ones in the N'th fibonacci word
    op fib_word(n);
        [a0, a1, b0, b1] := [0, 1, 1, 0];
        loop for i in [2..n] do
            [a0, a1, b0, b1] := [b0, b1, a0+b0, a1+b1];
        end loop;
        return [a0, a1];
    end op;

    op entropy(fibword);
        [zeroes, ones] := fibword;
        fzeroes := zeroes / (zeroes + ones);
        fones := ones / (zeroes + ones);

        if fzeroes = 0 or fones = 0 then
            return 0;
        end if;

        return -fzeroes*log fzeroes/log 2 - fones*log fones/log 2;
    end op;
end program;