syntax/ast: pretty printing

syntax/ast/ast.go

@@ -1,5 +1,10 @@
 package ast
 
+import (
+	"bytes"
+	"fmt"
+)
+
 type Node struct {
 	Parent   *Node
 	Children []*Node
@@ -36,6 +41,26 @@ func (a *Node) Equal(b *Node) bool {
 	return true
 }
 
+func (a *Node) String() string {
+	var buf bytes.Buffer
+	buf.WriteString(a.Kind.String())
+	if a.Value != nil {
+		buf.WriteString(" =")
+		buf.WriteString(fmt.Sprintf("%v", a.Value))
+	}
+	if len(a.Children) > 0 {
+		buf.WriteString(" [")
+		for i, c := range a.Children {
+			if i > 0 {
+				buf.WriteString(", ")
+			}
+			buf.WriteString(c.String())
+		}
+		buf.WriteString("]")
+	}
+	return buf.String()
+}
+
 func Insert(parent *Node, children ...*Node) {
 	parent.Children = append(parent.Children, children...)
 	for _, ch := range children {
@@ -70,3 +95,28 @@ const (
 	KindSingle
 	KindAnyOf
 )
+
+func (k Kind) String() string {
+	switch k {
+	case KindNothing:
+		return "Nothing"
+	case KindPattern:
+		return "Pattern"
+	case KindList:
+		return "List"
+	case KindRange:
+		return "Range"
+	case KindText:
+		return "Text"
+	case KindAny:
+		return "Any"
+	case KindSuper:
+		return "Super"
+	case KindSingle:
+		return "Single"
+	case KindAnyOf:
+		return "AnyOf"
+	default:
+		return ""
+	}
+}