trie.go

package example

type trie map[string]*trie

func (t *trie) Add(parts []string) {
	if len(parts) == 0 {
		return
	}
	child, ok := (*t)[parts[0]]
	if !ok {
		child = &trie{}
		(*t)[parts[0]] = child
	}
	child.Add(parts[1:])
}

func (t *trie) Prefix(max int) []string {
	if len(*t) != 1 || max == 0 {
		return nil
	}
	var key string
	for key = range *t {
		/* nothing */
	}
	return append([]string{key}, (*t)[key].Prefix(max-1)...)
}

type walker func(val string, parent interface{}) interface{}

func (t *trie) Walk(start interface{}, walk walker) []interface{} {
	var res []interface{}
	for key, value := range *t {
		parent := walk(key, start)
		res = append(res, parent)
		res = append(res, value.Walk(parent, walk)...)
	}
	return res
}