RosettaCodeData/Task/Fibonacci-sequence/Phix/fibonacci-sequence-1.phix

function fibonacci(integer n)     -- iterative, works for -ve numbers
atom a=0, b=1
    if n=0 then return 0 end if
    if abs(n)>=79 then ?9/0 end if  -- inaccuracies creep in above 78
    for i=1 to abs(n)-1 do
        {a,b} = {b,a+b}
    end for
    if n<0 and remainder(n,2)=0 then return -fcache[absn] end if
    return fcache[absn]
end function

for i=0 to 28 do
    if i then puts(1,", ") end if
    printf(1,"%d", fibonacci(i))
end for
puts(1,"\n")