func compileFilterSet(
s string, pos int, parent *types.Filter) (int, error) {
for pos < len(s) && s[pos] == '(' {
child, newPos, err := compileFilter(s, pos+1)
if err != nil {
return pos, err
}
pos = newPos
parent.Children = append(parent.Children, child)
}
if pos == len(s) {
return pos, errUnexpectedEOF
}
return pos + 1, nil
}
