func ss(str *utf8string.String, pos, length int) string {
p0, p1 := pos, pos+length
if p0 < 0 {
p0 = 0
}
l := p1 - p0
if p1 > str.RuneCount() {
p1 = str.RuneCount()
}
s := str.Slice(p0, p1)
if l > (p1 - p0) {
s = s + strings.Repeat(" ", l-(p1-p0))
}
return s
}
