Empty range is 1:0 or a+1:a or a:a-1 for any integer a. Closed ranges (for integers) are equivalent to open ranges since [a,b] is the same as [a,b+1). You just

Empty range is 1:0 or a+1:a or a:a-1 for any integer a. Closed ranges (for integers) are equivalent to open ranges since [a,b] is the same as [a,b+1). You just put the plus ones in the right places.