update dumper

visitor/dumper.go

@@ -1,4 +1,4 @@
-package visitor
+package visitor // Visitor implementations
 
 import (
 	"fmt"
@@ -11,15 +11,6 @@ import (
 	"github.com/z7zmey/php-parser/walker"
 )
 
-func isWalkerImplementsNodeInterface(w walker.Walkable) bool {
-	switch w.(type) {
-	case node.Node:
-		return true
-	default:
-		return false
-	}
-}
-
 // Dumper prints ast hierarchy to stdout
 // Also prints comments and positions attached to nodes
 type Dumper struct {
@@ -30,10 +21,6 @@ type Dumper struct {
 
 // EnterNode is invoked at every node in heirerchy
 func (d Dumper) EnterNode(w walker.Walkable) bool {
-	if !isWalkerImplementsNodeInterface(w) {
-		return false
-	}
-
 	n := w.(node.Node)
 
 	fmt.Printf("%v%v", d.Indent, reflect.TypeOf(n))

walker/walker.go

@@ -1,13 +1,15 @@
-package walker
+package walker // Node walking behavior
 
 // Walkable interface
+//
+// Every node must implement this interface
 type Walkable interface {
 	Walk(v Visitor)
 }
 
 // Visitor interface
 type Visitor interface {
-	EnterNode(w Walkable) bool             // EnterNode invoked for each node encountered by Walk.
-	GetChildrenVisitor(Key string) Visitor // GetChildrenVisitor returns visitor for children nodes
-	LeaveNode(w Walkable)                  // LeaveNode invoked after process node
+	EnterNode(w Walkable) bool             // EnterNode is invoked for each node encountered by Walk.
+	GetChildrenVisitor(Key string) Visitor // GetChildrenVisitor is invoked at every node parameter that contains children nodes
+	LeaveNode(w Walkable)                  // LeaveNode is invoked after process node
 }