node updates

internal/tree/node.go

@@ -3,9 +3,10 @@ package tree
 // Node is a struct containing nodes of a file tree.
 type Node struct {
 	// can be nil
-	Parent   *Node
-	Name     string
-	FileType string
+	Parent *Node
+	Name   string
+	// Empty value mean directory
+	Ext string
 	// cannot be nil; may have len 0
 	Children []*Node
 }
@@ -14,7 +15,8 @@ type Node struct {
 // parent and children are optional and can be nil,
 // in which case Parent will be stored as nil,
 // but Children will be initialized as []*Node of len 0.
-func NewNode(name string, ft string, parent *Node, children []*Node) *Node {
+// If ext == "", the Node is a directory.
+func NewNode(name string, ext string, parent *Node, children []*Node) *Node {
 	var c []*Node
 	if children == nil {
 		c = make([]*Node, 0)
@@ -23,7 +25,7 @@ func NewNode(name string, ft string, parent *Node, children []*Node) *Node {
 	}
 	n := &Node{
 		Name:     name,
-		FileType: ft,
+		Ext:      ext,
 		Parent:   parent,
 		Children: c,
 	}
@@ -37,3 +39,12 @@ func (n *Node) IsRoot() bool {
 func (n *Node) IsTail() bool {
 	return len(n.Children) == 0
 }
+
+func (n *Node) IsDir() bool {
+	return n.Ext == ""
+}
+
+// TODO: Implement recursive depth-first traversal to process a tree
+
+func Traverse(root *Node) {
+}