Add String() to Node struct.

parser/node.go

@@ -1,5 +1,10 @@
 package parser
 
+import (
+	"fmt"
+	"strings"
+)
+
 // Node is a node in the parse tree.
 type Node struct {
 	// Name is the name of the node.
@@ -10,6 +15,17 @@ type Node struct {
 	children []*Node
 }
 
+func (n *Node) String() string {
+	if len(n.children) == 0 {
+		return fmt.Sprintf("{%q: %q}", n.Name, n.value)
+	}
+	b := make([]string, len(n.children))
+	for i, c := range n.children {
+		b[i] = c.String()
+	}
+	return fmt.Sprintf("{%q: [%s]}", n.Name, strings.Join(b, ", "))
+}
+
 // NewNode creates a new node.
 func NewNode(name, value string) *Node {
 	return &Node{Name: name, value: value}

parser/node_test.go

@@ -0,0 +1,15 @@
+package parser_test
+
+import (
+	"fmt"
+
+	"github.com/0x51-dev/upeg/parser"
+)
+
+func ExampleNode_String() {
+	a := parser.NewNode("a", "0")
+	x := parser.NewParentNode("x", []*parser.Node{a})
+	fmt.Println(x)
+	// Output:
+	// {"x": [{"a": "0"}]}
+}