package main func ifNegative(a []string, n int) int { if n < 0 { n = len(a) + n } if n < 0 { n = 0 } else if n > len(a) { n = len(a) } return n } func Slice(a []string, nbr ...int) []string { if len(nbr) == 0 { return a } first := nbr[0] if len(nbr) == 1 { if first < 0 { first = len(a) + first if first < 0 { return a } } return a[first:] } second := nbr[1] first = ifNegative(a, first) second = ifNegative(a, second) if first > second { return nil } return a[first:second] } func main() { }