forced in-order nodes iteration (#9)

go.mod

@@ -1,3 +1,3 @@
 module github.com/s0rg/trie
 
-go 1.21.0
+go 1.22

node.go

@@ -1,7 +1,10 @@
 package trie
 
+import "slices"
+
 type node[T any] struct {
 	childs map[rune]*node[T]
+	order  []rune
 	parent *node[T]
 	value  T
 	ok     bool
@@ -37,6 +40,8 @@ func (n *node[T]) AddChild(r rune) (rv *node[T]) {
 
 	rv.parent = n
 	n.childs[r] = rv
+	n.order = append(n.order, r)
+	slices.Sort(n.order)
 
 	return rv
 }

trie.go

@@ -18,7 +18,9 @@ type Trie[T any] struct {
 
 // New creates empty Trie.
 func New[T any]() *Trie[T] {
-	return &Trie[T]{root: makeNode[T](rootNode)}
+	return &Trie[T]{
+		root: makeNode[T](rootNode),
+	}
 }
 
 // Add inserts new key/value pair.
@@ -61,8 +63,7 @@ func (t *Trie[T]) Del(key string) (ok bool) {
 	}
 
 	for ; n != nil; n = p {
-		p = n.Parent()
-		if p == nil {
+		if p = n.Parent(); p == nil {
 			break
 		}
 
@@ -142,7 +143,7 @@ func (t *Trie[T]) Common(prefix string, minLength int) (rv []string) {
 		return true
 	})
 
-	slices.SortStableFunc(rv, func(a, b string) int {
+	slices.SortFunc(rv, func(a, b string) int {
 		sa, _ := t.Suggest(a)
 		sb, _ := t.Suggest(b)
 
@@ -193,7 +194,9 @@ func dfsValues[T any](
 	prefix string,
 	handler func(key string, value T),
 ) {
-	for r, c := range n.childs {
+	for _, r := range n.order {
+		c := n.childs[r]
+
 		key := prefix + string(r)
 
 		if c.HasValue() {
@@ -209,7 +212,9 @@ func dfsKeys[T any](
 	prefix string,
 	handler func(string, *node[T]) bool,
 ) {
-	for r, c := range n.childs {
+	for _, r := range n.order {
+		c := n.childs[r]
+
 		key := prefix + string(r)
 
 		if !handler(key, c) {