RosettaCodeData/Task/Fibonacci-sequence/Falcon/fibonacci-sequence-1.falcon

function fib_i(n)

    if n < 2: return n

    fibPrev = 1
    fib = 1
    for i in [2:n]
        tmp = fib
        fib += fibPrev
        fibPrev = tmp
    end
    return fib
end