s := []string{"hello", "world", "foo", "bar"}
    fmt.Println(s) // [hello world foo bar]

    s = s[:0]
    fmt.Println(s) // []

    s = append(s, "XXX")
    s = s[:2]
    fmt.Println(s) // [XXX world]

This is why "delete(slice, n)" doesn't work and it only operates on maps.

I suppose clear(slice) could allocate a new array, but that's not the same behaviour as clear(map) either, and doesn't really represent the common understanding of "clearing a slice". The only behaviour I can think of that vaguely matches what "clearing a slice" means is what it does now.