func nextToken(s string) (t, tail string) {
	p := strings.Index(s[1:], "-")
	if p == -1 {
		return s[1:], ""
	}
	p++
	return s[1:p], s[p:]
}

// LanguageID returns an index, where 0 <= index < NumCompactTags, for tags
// for which data exists in the text repository.The index will change over time
// and should not be stored in persistent storage. If t does not match a compact

// index, exact will be false and the compact index will be returned for the
// first match after repeatedly taking the Parent of t.
func CompactIndex(t Tag) (index int, exact bool) {
	id, exact := compact.LanguageID(compact.Tag(t))
	return int(id), exact
}

var root = language.Tag{}

// Base is an ISO 639 language code, used for encoding the base language
// of a language tag.
type Base struct {