define('avg(a)i,sum') :(avg_end)
avg     i = i + 1; sum = sum + a<i> :s(avg)
        avg = 1.0 * sum / prototype(a) :(return)
avg_end

*       # Fill arrays
        str = '1 2 3 4 5 6 7 8 9 10'; arr = array(10)
loop    i = i + 1; str len(p) span('0123456789') . arr<i> @p :s(loop)
        empty = array(1) ;* Null vector

*       # Test and display
        output = '[' str '] -> ' avg(arr)
        output = '[ ] -> ' avg(empty)
end