walker

dumper.go

@@ -0,0 +1,26 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/z7zmey/php-parser/node"
+)
+
+type dumper struct {
+	indent string
+}
+
+func (d dumper) Visit(n node.Node) bool {
+	fmt.Printf("%v[%v]:\n", d.indent, n.Name())
+
+	return true
+}
+
+func (d dumper) Children(key string) node.Visitor {
+	fmt.Printf("%v%v:\n", d.indent+". ", key)
+	return dumper{d.indent + ". . "}
+}
+
+func (d dumper) Scalar(key string, value interface{}) {
+	fmt.Printf("%v%v: %v\n", d.indent+". ", key, value)
+}

main.go

@@ -1,7 +1,6 @@
 package main
 
 import (
-	"bytes"
 	"flag"
 	"fmt"
 	"log"
@@ -17,14 +16,12 @@ func main() {
 	for _, path := range flag.Args() {
 		real, err := realpath.Realpath(path)
 		checkErr(err)
-		fmt.Printf("\n==> %s", real)
+		fmt.Printf("==> %s\n", real)
 
 		src, _ := os.Open(string(real))
 		rootnode := parser.Parse(src, real)
 
-		buf := new(bytes.Buffer)
+		rootnode.Walk(dumper{"  | "})
-		rootnode.Print(buf, "")
-		fmt.Println(buf.String())
 	}
 }
 

node/argument.go

@@ -1,10 +1,5 @@
 package node
 
-import (
-	"fmt"
-	"io"
-)
-
 type Argument struct {
 	name     string
 	expr     Node
@@ -23,12 +18,13 @@ func NewArgument(expression Node, variadic bool) Node {
 	}
 }
 
-func (n Argument) Print(out io.Writer, indent string) {
+func (n Argument) Walk(v Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
-	fmt.Fprintf(out, "\n%vvariadic: %t", indent+"  ", n.variadic)
+		return
+	}
 
 	if n.expr != nil {
-		fmt.Fprintf(out, "\n%vexpr:", indent+"  ")
+		vv := v.Children("expr")
-		n.expr.Print(out, indent+"    ")
+		n.expr.Walk(vv)
 	}
 }

node/expr/array.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 	"github.com/z7zmey/php-parser/token"
 )
@@ -28,13 +25,15 @@ func NewArray(opentToken token.Token, closeToken token.Token, items []node.Node)
 	}
 }
 
-func (n Array) Print(out io.Writer, indent string) {
+func (n Array) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [%d %d]", indent, n.name, n.opentToken.StartLine, n.closeToken.EndLine)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.items != nil {
-		fmt.Fprintf(out, "\n%vitems:", indent+"  ")
+		vv := v.Children("items")
 		for _, nn := range n.items {
-			nn.Print(out, indent+"    ")
+			nn.Walk(vv)
 		}
 	}
 }

node/expr/array_dim_fetch.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -25,16 +22,18 @@ func NewArrayDimFetch(variable node.Node, dim node.Node) node.Node {
 	}
 }
 
-func (n ArrayDimFetch) Print(out io.Writer, indent string) {
+func (n ArrayDimFetch) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.Name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.variable != nil {
-		fmt.Fprintf(out, "\n%vvariable:", indent+"  ")
+		vv := v.Children("variable")
-		n.variable.Print(out, indent+"    ")
+		n.variable.Walk(vv)
 	}
 
 	if n.dim != nil {
-		fmt.Fprintf(out, "\n%vdim:", indent+"  ")
+		vv := v.Children("dim")
-		n.dim.Print(out, indent+"    ")
+		n.dim.Walk(vv)
 	}
 }

node/expr/array_item.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -27,17 +24,18 @@ func NewArrayItem(key node.Node, val node.Node, byRef bool) node.Node {
 	}
 }
 
-func (n ArrayItem) Print(out io.Writer, indent string) {
+func (n ArrayItem) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
-	fmt.Fprintf(out, "\n%vbyRef: %t", indent+"  ", n.byRef)
+		return
+	}
 
 	if n.key != nil {
-		fmt.Fprintf(out, "\n%vkey:", indent+"  ")
+		vv := v.Children("key")
-		n.key.Print(out, indent+"    ")
+		n.key.Walk(vv)
 	}
 
 	if n.val != nil {
-		fmt.Fprintf(out, "\n%vval:", indent+"  ")
+		vv := v.Children("val")
-		n.val.Print(out, indent+"    ")
+		n.val.Walk(vv)
 	}
 }

node/expr/assign_op/assign.go

@@ -21,3 +21,19 @@ func NewAssign(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n Assign) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.variable != nil {
+		vv := v.Children("variable")
+		n.variable.Walk(vv)
+	}
+
+	if n.expression != nil {
+		vv := v.Children("expression")
+		n.expression.Walk(vv)
+	}
+}

node/expr/assign_op/assign_op.go

@@ -1,9 +1,6 @@
 package assign_op
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -12,17 +9,3 @@ type AssignOp struct {
 	variable   node.Node
 	expression node.Node
 }
-
-func (n AssignOp) Print(out io.Writer, indent string) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
-
-	if n.variable != nil {
-		fmt.Fprintf(out, "\n%vvariable:", indent+"  ")
-		n.variable.Print(out, indent+"    ")
-	}
-
-	if n.expression != nil {
-		fmt.Fprintf(out, "\n%vexpression:", indent+"  ")
-		n.expression.Print(out, indent+"    ")
-	}
-}

node/expr/assign_op/assign_ref.go

@@ -21,3 +21,19 @@ func NewAssignRef(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n AssignRef) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.variable != nil {
+		vv := v.Children("variable")
+		n.variable.Walk(vv)
+	}
+
+	if n.expression != nil {
+		vv := v.Children("expression")
+		n.expression.Walk(vv)
+	}
+}

node/expr/assign_op/bitwise_and.go

@@ -21,3 +21,19 @@ func NewBitwiseAnd(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n BitwiseAnd) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.variable != nil {
+		vv := v.Children("variable")
+		n.variable.Walk(vv)
+	}
+
+	if n.expression != nil {
+		vv := v.Children("expression")
+		n.expression.Walk(vv)
+	}
+}

node/expr/assign_op/bitwise_or.go

@@ -21,3 +21,19 @@ func NewBitwiseOr(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n BitwiseOr) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.variable != nil {
+		vv := v.Children("variable")
+		n.variable.Walk(vv)
+	}
+
+	if n.expression != nil {
+		vv := v.Children("expression")
+		n.expression.Walk(vv)
+	}
+}

node/expr/assign_op/bitwise_xor.go

@@ -21,3 +21,19 @@ func NewBitwiseXor(variable node.Node, expression node.Node) node.Node {
 func (n BitwiseXor) Name() string {
 	return "BitwiseXor"
 }
+
+func (n BitwiseXor) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.variable != nil {
+		vv := v.Children("variable")
+		n.variable.Walk(vv)
+	}
+
+	if n.expression != nil {
+		vv := v.Children("expression")
+		n.expression.Walk(vv)
+	}
+}

node/expr/assign_op/concat.go

@@ -21,3 +21,19 @@ func NewConcat(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n Concat) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.variable != nil {
+		vv := v.Children("variable")
+		n.variable.Walk(vv)
+	}
+
+	if n.expression != nil {
+		vv := v.Children("expression")
+		n.expression.Walk(vv)
+	}
+}

node/expr/assign_op/div.go

@@ -21,3 +21,19 @@ func NewDiv(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n Div) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.variable != nil {
+		vv := v.Children("variable")
+		n.variable.Walk(vv)
+	}
+
+	if n.expression != nil {
+		vv := v.Children("expression")
+		n.expression.Walk(vv)
+	}
+}

node/expr/assign_op/minus.go

@@ -21,3 +21,19 @@ func NewMinus(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n Minus) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.variable != nil {
+		vv := v.Children("variable")
+		n.variable.Walk(vv)
+	}
+
+	if n.expression != nil {
+		vv := v.Children("expression")
+		n.expression.Walk(vv)
+	}
+}

node/expr/assign_op/mod.go

@@ -21,3 +21,19 @@ func NewMod(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n Mod) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.variable != nil {
+		vv := v.Children("variable")
+		n.variable.Walk(vv)
+	}
+
+	if n.expression != nil {
+		vv := v.Children("expression")
+		n.expression.Walk(vv)
+	}
+}

node/expr/assign_op/mul.go

@@ -21,3 +21,19 @@ func NewMul(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n Mul) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.variable != nil {
+		vv := v.Children("variable")
+		n.variable.Walk(vv)
+	}
+
+	if n.expression != nil {
+		vv := v.Children("expression")
+		n.expression.Walk(vv)
+	}
+}

node/expr/assign_op/plus.go

@@ -21,3 +21,19 @@ func NewPlus(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n Plus) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.variable != nil {
+		vv := v.Children("variable")
+		n.variable.Walk(vv)
+	}
+
+	if n.expression != nil {
+		vv := v.Children("expression")
+		n.expression.Walk(vv)
+	}
+}

node/expr/assign_op/pow.go

@@ -21,3 +21,19 @@ func NewPow(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n Pow) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.variable != nil {
+		vv := v.Children("variable")
+		n.variable.Walk(vv)
+	}
+
+	if n.expression != nil {
+		vv := v.Children("expression")
+		n.expression.Walk(vv)
+	}
+}

node/expr/assign_op/shift_left.go

@@ -21,3 +21,19 @@ func NewShiftLeft(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n ShiftLeft) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.variable != nil {
+		vv := v.Children("variable")
+		n.variable.Walk(vv)
+	}
+
+	if n.expression != nil {
+		vv := v.Children("expression")
+		n.expression.Walk(vv)
+	}
+}

node/expr/assign_op/shift_right.go

@@ -21,3 +21,19 @@ func NewShiftRight(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n ShiftRight) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.variable != nil {
+		vv := v.Children("variable")
+		n.variable.Walk(vv)
+	}
+
+	if n.expression != nil {
+		vv := v.Children("expression")
+		n.expression.Walk(vv)
+	}
+}

node/expr/binary_op/binary_op.go

@@ -1,9 +1,6 @@
 package binary_op
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -12,17 +9,3 @@ type BinaryOp struct {
 	left  node.Node
 	right node.Node
 }
-
-func (n BinaryOp) Print(out io.Writer, indent string) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
-
-	if n.left != nil {
-		fmt.Fprintf(out, "\n%vleft:", indent+"  ")
-		n.left.Print(out, indent+"    ")
-	}
-
-	if n.right != nil {
-		fmt.Fprintf(out, "\n%vright:", indent+"  ")
-		n.right.Print(out, indent+"    ")
-	}
-}

node/expr/binary_op/bitwise_and.go

@@ -21,3 +21,19 @@ func NewBitwiseAnd(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n BitwiseAnd) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/binary_op/bitwise_or.go

@@ -21,3 +21,19 @@ func NewBitwiseOr(variable node.Node, expression node.Node) node.Node {
 func (n BitwiseOr) Name() string {
 	return "BitwiseOr"
 }
+
+func (n BitwiseOr) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/binary_op/bitwise_xor.go

@@ -21,3 +21,19 @@ func NewBitwiseXor(variable node.Node, expression node.Node) node.Node {
 func (n BitwiseXor) Name() string {
 	return "BitwiseXor"
 }
+
+func (n BitwiseXor) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/binary_op/boolean_and.go

@@ -21,3 +21,19 @@ func NewBooleanAnd(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n BooleanAnd) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/binary_op/boolean_or.go

@@ -21,3 +21,19 @@ func NewBooleanOr(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n BooleanOr) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/binary_op/coalesce.go

@@ -21,3 +21,19 @@ func NewCoalesce(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n Coalesce) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/binary_op/concat.go

@@ -21,3 +21,19 @@ func NewConcat(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n Concat) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/binary_op/div.go

@@ -21,3 +21,19 @@ func NewDiv(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n Div) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/binary_op/equal.go

@@ -21,3 +21,19 @@ func NewEqual(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n Equal) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/binary_op/greater.go

@@ -21,3 +21,19 @@ func NewGreater(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n Greater) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/binary_op/greater_or_equal.go

@@ -21,3 +21,19 @@ func NewGreaterOrEqual(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n GreaterOrEqual) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/binary_op/identical.go

@@ -21,3 +21,19 @@ func NewIdentical(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n Identical) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/binary_op/logical_and.go

@@ -21,3 +21,19 @@ func NewLogicalAnd(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n LogicalAnd) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/binary_op/logical_or.go

@@ -21,3 +21,19 @@ func NewLogicalOr(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n LogicalOr) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/binary_op/logical_xor.go

@@ -21,3 +21,19 @@ func NewLogicalXor(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n LogicalXor) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/binary_op/minus.go

@@ -21,3 +21,19 @@ func NewMinus(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n Minus) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/binary_op/mod.go

@@ -4,7 +4,7 @@ import (
 	"github.com/z7zmey/php-parser/node"
 )
 
-func(n Mod) Name() string {
+func (n Mod) Name() string {
 	return "Mod"
 }
 
@@ -21,3 +21,19 @@ func NewMod(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n Mod) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/binary_op/mul.go

@@ -4,7 +4,7 @@ import (
 	"github.com/z7zmey/php-parser/node"
 )
 
-func(n Mul) Name() string {
+func (n Mul) Name() string {
 	return "Mul"
 }
 
@@ -21,3 +21,19 @@ func NewMul(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n Mul) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/binary_op/not_equal.go

@@ -4,7 +4,7 @@ import (
 	"github.com/z7zmey/php-parser/node"
 )
 
-func(n NotEqual) Name() string {
+func (n NotEqual) Name() string {
 	return "NotEqual"
 }
 
@@ -21,3 +21,19 @@ func NewNotEqual(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n NotEqual) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/binary_op/not_identical.go

@@ -4,7 +4,7 @@ import (
 	"github.com/z7zmey/php-parser/node"
 )
 
-func(n NotIdentical) Name() string {
+func (n NotIdentical) Name() string {
 	return "NotIdentical"
 }
 
@@ -21,3 +21,19 @@ func NewNotIdentical(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n NotIdentical) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/binary_op/plus.go

@@ -4,7 +4,7 @@ import (
 	"github.com/z7zmey/php-parser/node"
 )
 
-func(n Plus) Name() string {
+func (n Plus) Name() string {
 	return "Plus"
 }
 
@@ -21,3 +21,19 @@ func NewPlus(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n Plus) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/binary_op/pow.go

@@ -4,7 +4,7 @@ import (
 	"github.com/z7zmey/php-parser/node"
 )
 
-func(n Pow) Name() string {
+func (n Pow) Name() string {
 	return "Pow"
 }
 
@@ -21,3 +21,19 @@ func NewPow(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n Pow) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/binary_op/shift_left.go

@@ -4,7 +4,7 @@ import (
 	"github.com/z7zmey/php-parser/node"
 )
 
-func(n ShiftLeft) Name() string {
+func (n ShiftLeft) Name() string {
 	return "ShiftLeft"
 }
 
@@ -21,3 +21,19 @@ func NewShiftLeft(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n ShiftLeft) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/binary_op/shift_right.go

@@ -4,7 +4,7 @@ import (
 	"github.com/z7zmey/php-parser/node"
 )
 
-func(n ShiftRight) Name() string {
+func (n ShiftRight) Name() string {
 	return "ShiftRight"
 }
 
@@ -21,3 +21,19 @@ func NewShiftRight(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n ShiftRight) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/binary_op/smaller.go

@@ -4,7 +4,7 @@ import (
 	"github.com/z7zmey/php-parser/node"
 )
 
-func(n Smaller) Name() string {
+func (n Smaller) Name() string {
 	return "Smaller"
 }
 
@@ -21,3 +21,19 @@ func NewSmaller(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n Smaller) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/binary_op/smaller_or_equal.go

@@ -4,7 +4,7 @@ import (
 	"github.com/z7zmey/php-parser/node"
 )
 
-func(n SmallerOrEqual) Name() string {
+func (n SmallerOrEqual) Name() string {
 	return "SmallerOrEqual"
 }
 
@@ -21,3 +21,19 @@ func NewSmallerOrEqual(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n SmallerOrEqual) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/binary_op/spaceship.go

@@ -4,7 +4,7 @@ import (
 	"github.com/z7zmey/php-parser/node"
 )
 
-func(n Spaceship) Name() string {
+func (n Spaceship) Name() string {
 	return "Spaceship"
 }
 
@@ -21,3 +21,19 @@ func NewSpaceship(variable node.Node, expression node.Node) node.Node {
 		},
 	}
 }
+
+func (n Spaceship) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.left != nil {
+		vv := v.Children("left")
+		n.left.Walk(vv)
+	}
+
+	if n.right != nil {
+		vv := v.Children("right")
+		n.right.Walk(vv)
+	}
+}

node/expr/bitwise_not.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -23,11 +20,13 @@ func NewBitwiseNot(expression node.Node) node.Node {
 	}
 }
 
-func (n BitwiseNot) Print(out io.Writer, indent string) {
+func (n BitwiseNot) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.expr != nil {
-		fmt.Fprintf(out, "\n%vexpr:", indent+"  ")
+		vv := v.Children("expr")
-		n.expr.Print(out, indent+"    ")
+		n.expr.Walk(vv)
 	}
 }

node/expr/boolean_not.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -23,11 +20,13 @@ func NewBooleanNot(expression node.Node) node.Node {
 	}
 }
 
-func (n BooleanNot) Print(out io.Writer, indent string) {
+func (n BooleanNot) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.expr != nil {
-		fmt.Fprintf(out, "\n%vexpr:", indent+"  ")
+		vv := v.Children("expr")
-		n.expr.Print(out, indent+"    ")
+		n.expr.Walk(vv)
 	}
 }

node/expr/cast/cast.go

@@ -1,9 +1,6 @@
 package cast
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -11,12 +8,3 @@ type Cast struct {
 	name string
 	expr node.Node
 }
-
-func (n Cast) Print(out io.Writer, indent string) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
-
-	if n.expr != nil {
-		fmt.Fprintf(out, "\n%vexpr:", indent+"  ")
-		n.expr.Print(out, indent+"    ")
-	}
-}

node/expr/cast/cast_array.go

@@ -20,3 +20,14 @@ func NewCastArray(expr node.Node) node.Node {
 		},
 	}
 }
+
+func (n CastArray) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.expr != nil {
+		vv := v.Children("expr")
+		n.expr.Walk(vv)
+	}
+}

node/expr/cast/cast_bool.go

@@ -20,3 +20,14 @@ func NewCastBool(expr node.Node) node.Node {
 		},
 	}
 }
+
+func (n CastBool) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.expr != nil {
+		vv := v.Children("expr")
+		n.expr.Walk(vv)
+	}
+}

node/expr/cast/cast_double.go

@@ -20,3 +20,14 @@ func NewCastDouble(expr node.Node) node.Node {
 		},
 	}
 }
+
+func (n CastDouble) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.expr != nil {
+		vv := v.Children("expr")
+		n.expr.Walk(vv)
+	}
+}

node/expr/cast/cast_int.go

@@ -20,3 +20,14 @@ func NewCastInt(expr node.Node) node.Node {
 		},
 	}
 }
+
+func (n CastInt) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.expr != nil {
+		vv := v.Children("expr")
+		n.expr.Walk(vv)
+	}
+}

node/expr/cast/cast_object.go

@@ -20,3 +20,14 @@ func NewCastObject(expr node.Node) node.Node {
 		},
 	}
 }
+
+func (n CastObject) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.expr != nil {
+		vv := v.Children("expr")
+		n.expr.Walk(vv)
+	}
+}

node/expr/cast/cast_string.go

@@ -20,3 +20,14 @@ func NewCastString(expr node.Node) node.Node {
 		},
 	}
 }
+
+func (n CastString) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.expr != nil {
+		vv := v.Children("expr")
+		n.expr.Walk(vv)
+	}
+}

node/expr/cast/cast_unset.go

@@ -20,3 +20,14 @@ func NewCastUnset(expr node.Node) node.Node {
 		},
 	}
 }
+
+func (n CastUnset) Walk(v node.Visitor) {
+	if v.Visit(n) == false {
+		return
+	}
+
+	if n.expr != nil {
+		vv := v.Children("expr")
+		n.expr.Walk(vv)
+	}
+}

node/expr/class_const_fetch.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 	"github.com/z7zmey/php-parser/token"
 )
@@ -18,6 +15,7 @@ type ClassConstFetch struct {
 	constant token.Token
 }
 
+// TODO: constant must be identifier
 func NewClassConstFetch(class node.Node, constant token.Token) node.Node {
 	return ClassConstFetch{
 		"ClassConstFetch",
@@ -26,12 +24,15 @@ func NewClassConstFetch(class node.Node, constant token.Token) node.Node {
 	}
 }
 
-func (n ClassConstFetch) Print(out io.Writer, indent string) {
+func (n ClassConstFetch) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
-	fmt.Fprintf(out, "\n%vname: %q", indent+"  ", n.constant.Value)
+		return
+	}
+
+	v.Scalar("constant", n.constant.Value)
 
 	if n.class != nil {
-		fmt.Fprintf(out, "\n%vclass:", indent+"  ")
+		vv := v.Children("class")
-		n.class.Print(out, indent+"    ")
+		n.class.Walk(vv)
 	}
 }

node/expr/clone.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -23,11 +20,13 @@ func NewClone(expression node.Node) node.Node {
 	}
 }
 
-func (n Clone) Print(out io.Writer, indent string) {
+func (n Clone) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.expr != nil {
-		fmt.Fprintf(out, "\n%vexpr:", indent+"  ")
+		vv := v.Children("expr")
-		n.expr.Print(out, indent+"    ")
+		n.expr.Walk(vv)
 	}
 }

node/expr/closure.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -33,35 +30,37 @@ func NewClosure(params []node.Node, uses []node.Node, returnType node.Node, stmt
 	}
 }
 
-func (n Closure) Print(out io.Writer, indent string) {
+func (n Closure) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
-	fmt.Fprintf(out, "\n%vis static: %t", indent+"  ", n.isStatic)
+	v.Scalar("isStatic", n.isStatic)
-	fmt.Fprintf(out, "\n%vis return ref: %t", indent+"  ", n.isReturnRef)
+	v.Scalar("isReturnRef", n.isReturnRef)
 
 	if n.params != nil {
-		fmt.Fprintf(out, "\n%vparams:", indent+"  ")
+		vv := v.Children("params")
 		for _, nn := range n.params {
-			nn.Print(out, indent+"    ")
+			nn.Walk(vv)
 		}
 	}
 
 	if n.uses != nil {
-		fmt.Fprintf(out, "\n%vuses:", indent+"  ")
+		vv := v.Children("uses")
 		for _, nn := range n.uses {
-			nn.Print(out, indent+"    ")
+			nn.Walk(vv)
 		}
 	}
 
 	if n.returnType != nil {
-		fmt.Fprintf(out, "\n%vreturn type:", indent+"  ")
+		vv := v.Children("returnType")
-		n.returnType.Print(out, indent+"    ")
+		n.returnType.Walk(vv)
 	}
 
 	if n.stmts != nil {
-		fmt.Fprintf(out, "\n%vstmts:", indent+"  ")
+		vv := v.Children("stmts")
 		for _, nn := range n.stmts {
-			nn.Print(out, indent+"    ")
+			nn.Walk(vv)
 		}
 	}
 }

node/expr/closure_use.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -25,12 +22,15 @@ func NewClusureUse(variable node.Node, byRef bool) node.Node {
 	}
 }
 
-func (n ClusureUse) Print(out io.Writer, indent string) {
+func (n ClusureUse) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
-	fmt.Fprintf(out, "\n%vby ref: %t", indent+"  ", n.byRef)
+		return
+	}
+
+	v.Scalar("byRef", n.byRef)
 
 	if n.variable != nil {
-		fmt.Fprintf(out, "\n%vvariable:", indent+"  ")
+		vv := v.Children("variable")
-		n.variable.Print(out, indent+"    ")
+		n.variable.Walk(vv)
 	}
 }

node/expr/const_fetch.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -23,11 +20,13 @@ func NewConstFetch(constant node.Node) node.Node {
 	}
 }
 
-func (n ConstFetch) Print(out io.Writer, indent string) {
+func (n ConstFetch) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.constant != nil {
-		fmt.Fprintf(out, "\n%vconstant:", indent+"  ")
+		vv := v.Children("constant")
-		n.constant.Print(out, indent+"    ")
+		n.constant.Walk(vv)
 	}
 }

node/expr/empty.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -23,11 +20,13 @@ func NewEmpty(expression node.Node) node.Node {
 	}
 }
 
-func (n Empty) Print(out io.Writer, indent string) {
+func (n Empty) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.expr != nil {
-		fmt.Fprintf(out, "\n%vexpr:", indent+"  ")
+		vv := v.Children("expr")
-		n.expr.Print(out, indent+"    ")
+		n.expr.Walk(vv)
 	}
 }

node/expr/error_suppress.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -23,11 +20,13 @@ func NewErrorSuppress(expression node.Node) node.Node {
 	}
 }
 
-func (n ErrorSuppress) Print(out io.Writer, indent string) {
+func (n ErrorSuppress) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.expr != nil {
-		fmt.Fprintf(out, "\n%vexpr:", indent+"  ")
+		vv := v.Children("expr")
-		n.expr.Print(out, indent+"    ")
+		n.expr.Walk(vv)
 	}
 }

node/expr/eval.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -23,11 +20,13 @@ func NewEval(expression node.Node) node.Node {
 	}
 }
 
-func (n Eval) Print(out io.Writer, indent string) {
+func (n Eval) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.expr != nil {
-		fmt.Fprintf(out, "\n%vexpr:", indent+"  ")
+		vv := v.Children("expr")
-		n.expr.Print(out, indent+"    ")
+		n.expr.Walk(vv)
 	}
 }

node/expr/exit.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -25,12 +22,13 @@ func NewExit(expr node.Node, isDie bool) node.Node {
 	}
 }
 
-func (n Exit) Print(out io.Writer, indent string) {
+func (n Exit) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
-	fmt.Fprintf(out, "\n%vis die: %t", indent+"  ", n.isDie)
+		return
+	}
 
 	if n.expr != nil {
-		fmt.Fprintf(out, "\n%vexpr:", indent+"  ")
+		vv := v.Children("expr")
-		n.expr.Print(out, indent+"    ")
+		n.expr.Walk(vv)
 	}
 }

node/expr/function_call.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -25,18 +22,20 @@ func NewFunctionCall(function node.Node, arguments []node.Node) node.Node {
 	}
 }
 
-func (n FunctionCall) Print(out io.Writer, indent string) {
+func (n FunctionCall) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.function != nil {
-		fmt.Fprintf(out, "\n%vfunction:", indent+"  ")
+		vv := v.Children("function")
-		n.function.Print(out, indent+"    ")
+		n.function.Walk(vv)
 	}
 
 	if n.arguments != nil {
-		fmt.Fprintf(out, "\n%varguments:", indent+"  ")
+		vv := v.Children("arguments")
 		for _, nn := range n.arguments {
-			nn.Print(out, indent+"    ")
+			nn.Walk(vv)
 		}
 	}
 }

node/expr/include.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -23,11 +20,13 @@ func NewInclude(expression node.Node) node.Node {
 	}
 }
 
-func (n Include) Print(out io.Writer, indent string) {
+func (n Include) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.expr != nil {
-		fmt.Fprintf(out, "\n%vexpr:", indent+"  ")
+		vv := v.Children("expr")
-		n.expr.Print(out, indent+"    ")
+		n.expr.Walk(vv)
 	}
 }

node/expr/include_once.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -23,11 +20,13 @@ func NewIncludeOnce(expression node.Node) node.Node {
 	}
 }
 
-func (n IncludeOnce) Print(out io.Writer, indent string) {
+func (n IncludeOnce) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.expr != nil {
-		fmt.Fprintf(out, "\n%vexpr:", indent+"  ")
+		vv := v.Children("expr")
-		n.expr.Print(out, indent+"    ")
+		n.expr.Walk(vv)
 	}
 }

node/expr/instance_of.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -25,16 +22,18 @@ func NewInstanceOf(expr node.Node, class node.Node) node.Node {
 	}
 }
 
-func (n InstanceOf) Print(out io.Writer, indent string) {
+func (n InstanceOf) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.expr != nil {
-		fmt.Fprintf(out, "\n%vexpr:", indent+"  ")
+		vv := v.Children("expr")
-		n.expr.Print(out, indent+"    ")
+		n.expr.Walk(vv)
 	}
 
 	if n.class != nil {
-		fmt.Fprintf(out, "\n%vclass:", indent+"  ")
+		vv := v.Children("class")
-		n.class.Print(out, indent+"    ")
+		n.class.Walk(vv)
 	}
 }

node/expr/isset.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -23,13 +20,15 @@ func NewIsset(variables []node.Node) node.Node {
 	}
 }
 
-func (n Isset) Print(out io.Writer, indent string) {
+func (n Isset) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.variables != nil {
-		fmt.Fprintf(out, "\n%vvariables:", indent+"  ")
+		vv := v.Children("variables")
 		for _, nn := range n.variables {
-			nn.Print(out, indent+"    ")
+			nn.Walk(vv)
 		}
 	}
 }

node/expr/list.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -23,13 +20,15 @@ func NewList(items []node.Node) node.Node {
 	}
 }
 
-func (n List) Print(out io.Writer, indent string) {
+func (n List) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.items != nil {
-		fmt.Fprintf(out, "\n%vitems:", indent+"  ")
+		vv := v.Children("items")
 		for _, nn := range n.items {
-			nn.Print(out, indent+"    ")
+			nn.Walk(vv)
 		}
 	}
 }

node/expr/method_call.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -27,23 +24,25 @@ func NewMethodCall(variable node.Node, method node.Node, arguments []node.Node)
 	}
 }
 
-func (n MethodCall) Print(out io.Writer, indent string) {
+func (n MethodCall) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.variable != nil {
-		fmt.Fprintf(out, "\n%vvariable:", indent+"  ")
+		vv := v.Children("variable")
-		n.variable.Print(out, indent+"    ")
+		n.variable.Walk(vv)
 	}
 
 	if n.method != nil {
-		fmt.Fprintf(out, "\n%vmethod:", indent+"  ")
+		vv := v.Children("method")
-		n.method.Print(out, indent+"    ")
+		n.method.Walk(vv)
 	}
 
 	if n.arguments != nil {
-		fmt.Fprintf(out, "\n%varguments:", indent+"  ")
+		vv := v.Children("arguments")
 		for _, nn := range n.arguments {
-			nn.Print(out, indent+"    ")
+			nn.Walk(vv)
 		}
 	}
 }

node/expr/new.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -25,18 +22,20 @@ func NewNew(class node.Node, arguments []node.Node) node.Node {
 	}
 }
 
-func (n New) Print(out io.Writer, indent string) {
+func (n New) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.class != nil {
-		fmt.Fprintf(out, "\n%vclass:", indent+"  ")
+		vv := v.Children("class")
-		n.class.Print(out, indent+"    ")
+		n.class.Walk(vv)
 	}
 
 	if n.arguments != nil {
-		fmt.Fprintf(out, "\n%varguments:", indent+"  ")
+		vv := v.Children("arguments")
 		for _, nn := range n.arguments {
-			nn.Print(out, indent+"    ")
+			nn.Walk(vv)
 		}
 	}
 }

node/expr/post_dec.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -23,11 +20,13 @@ func NewPostDec(variableession node.Node) node.Node {
 	}
 }
 
-func (n PostDec) Print(out io.Writer, indent string) {
+func (n PostDec) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.variable != nil {
-		fmt.Fprintf(out, "\n%vvariable:", indent+"  ")
+		vv := v.Children("variable")
-		n.variable.Print(out, indent+"    ")
+		n.variable.Walk(vv)
 	}
 }

node/expr/post_inc.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -23,11 +20,13 @@ func NewPostInc(variableession node.Node) node.Node {
 	}
 }
 
-func (n PostInc) Print(out io.Writer, indent string) {
+func (n PostInc) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.variable != nil {
-		fmt.Fprintf(out, "\n%vvariable:", indent+"  ")
+		vv := v.Children("variable")
-		n.variable.Print(out, indent+"    ")
+		n.variable.Walk(vv)
 	}
 }

node/expr/pre_dec.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -23,11 +20,13 @@ func NewPreDec(variableession node.Node) node.Node {
 	}
 }
 
-func (n PreDec) Print(out io.Writer, indent string) {
+func (n PreDec) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.variable != nil {
-		fmt.Fprintf(out, "\n%vvariable:", indent+"  ")
+		vv := v.Children("variable")
-		n.variable.Print(out, indent+"    ")
+		n.variable.Walk(vv)
 	}
 }

node/expr/pre_inc.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -23,11 +20,13 @@ func NewPreInc(variableession node.Node) node.Node {
 	}
 }
 
-func (n PreInc) Print(out io.Writer, indent string) {
+func (n PreInc) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.variable != nil {
-		fmt.Fprintf(out, "\n%vvariable:", indent+"  ")
+		vv := v.Children("variable")
-		n.variable.Print(out, indent+"    ")
+		n.variable.Walk(vv)
 	}
 }

node/expr/print.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -23,11 +20,13 @@ func NewPrint(expression node.Node) node.Node {
 	}
 }
 
-func (n Print) Print(out io.Writer, indent string) {
+func (n Print) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.expr != nil {
-		fmt.Fprintf(out, "\n%vexpr:", indent+"  ")
+		vv := v.Children("expr")
-		n.expr.Print(out, indent+"    ")
+		n.expr.Walk(vv)
 	}
 }

node/expr/property_fetch.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -25,16 +22,18 @@ func NewPropertyFetch(variable node.Node, property node.Node) node.Node {
 	}
 }
 
-func (n PropertyFetch) Print(out io.Writer, indent string) {
+func (n PropertyFetch) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.variable != nil {
-		fmt.Fprintf(out, "\n%vvariable:", indent+"  ")
+		vv := v.Children("variable")
-		n.variable.Print(out, indent+"    ")
+		n.variable.Walk(vv)
 	}
 
 	if n.property != nil {
-		fmt.Fprintf(out, "\n%vproperty:", indent+"  ")
+		vv := v.Children("property")
-		n.property.Print(out, indent+"    ")
+		n.property.Walk(vv)
 	}
 }

node/expr/require.go

@@ -1,13 +1,10 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
-func(n Require) Name() string {
+func (n Require) Name() string {
 	return "Require"
 }
 
@@ -23,11 +20,13 @@ func NewRequire(expression node.Node) node.Node {
 	}
 }
 
-func (n Require) Print(out io.Writer, indent string) {
+func (n Require) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.expr != nil {
-		fmt.Fprintf(out, "\n%vexpr:", indent+"  ")
+		vv := v.Children("expr")
-		n.expr.Print(out, indent+"    ")
+		n.expr.Walk(vv)
 	}
 }

node/expr/require_once.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -23,11 +20,13 @@ func NewRequireOnce(expression node.Node) node.Node {
 	}
 }
 
-func (n RequireOnce) Print(out io.Writer, indent string) {
+func (n RequireOnce) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.expr != nil {
-		fmt.Fprintf(out, "\n%vexpr:", indent+"  ")
+		vv := v.Children("expr")
-		n.expr.Print(out, indent+"    ")
+		n.expr.Walk(vv)
 	}
 }

node/expr/shell_exec.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -23,13 +20,15 @@ func NewShellExec(parts []node.Node) node.Node {
 	}
 }
 
-func (n ShellExec) Print(out io.Writer, indent string) {
+func (n ShellExec) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.parts != nil {
-		fmt.Fprintf(out, "\n%vparts:", indent+"  ")
+		vv := v.Children("parts")
 		for _, nn := range n.parts {
-			nn.Print(out, indent+"    ")
+			nn.Walk(vv)
 		}
 	}
 }

node/expr/short_array.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 	"github.com/z7zmey/php-parser/token"
 )
@@ -28,13 +25,15 @@ func NewShortArray(opentToken token.Token, closeToken token.Token, items []node.
 	}
 }
 
-func (n ShortArray) Print(out io.Writer, indent string) {
+func (n ShortArray) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [%d %d]", indent, n.name, n.opentToken.StartLine, n.closeToken.EndLine)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.items != nil {
-		fmt.Fprintf(out, "\n%vitems:", indent+"  ")
+		vv := v.Children("items")
 		for _, nn := range n.items {
-			nn.Print(out, indent+"    ")
+			nn.Walk(vv)
 		}
 	}
 }

node/expr/short_list.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -23,13 +20,15 @@ func NewShortList(items []node.Node) node.Node {
 	}
 }
 
-func (n ShortList) Print(out io.Writer, indent string) {
+func (n ShortList) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.items != nil {
-		fmt.Fprintf(out, "\n%vitems:", indent+"  ")
+		vv := v.Children("items")
 		for _, nn := range n.items {
-			nn.Print(out, indent+"    ")
+			nn.Walk(vv)
 		}
 	}
 }

node/expr/static_call.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -27,23 +24,25 @@ func NewStaticCall(class node.Node, call node.Node, arguments []node.Node) node.
 	}
 }
 
-func (n StaticCall) Print(out io.Writer, indent string) {
+func (n StaticCall) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.class != nil {
-		fmt.Fprintf(out, "\n%vclass:", indent+"  ")
+		vv := v.Children("class")
-		n.class.Print(out, indent+"    ")
+		n.class.Walk(vv)
 	}
 
 	if n.call != nil {
-		fmt.Fprintf(out, "\n%vcall:", indent+"  ")
+		vv := v.Children("call")
-		n.call.Print(out, indent+"    ")
+		n.call.Walk(vv)
 	}
 
 	if n.arguments != nil {
-		fmt.Fprintf(out, "\n%varguments:", indent+"  ")
+		vv := v.Children("arguments")
 		for _, nn := range n.arguments {
-			nn.Print(out, indent+"    ")
+			nn.Walk(vv)
 		}
 	}
 }

node/expr/static_property_fetch.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -25,16 +22,18 @@ func NewStaticPropertyFetch(class node.Node, property node.Node) node.Node {
 	}
 }
 
-func (n StaticPropertyFetch) Print(out io.Writer, indent string) {
+func (n StaticPropertyFetch) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.class != nil {
-		fmt.Fprintf(out, "\n%vclass:", indent+"  ")
+		vv := v.Children("class")
-		n.class.Print(out, indent+"    ")
+		n.class.Walk(vv)
 	}
 
 	if n.property != nil {
-		fmt.Fprintf(out, "\n%vproperty:", indent+"  ")
+		vv := v.Children("property")
-		n.property.Print(out, indent+"    ")
+		n.property.Walk(vv)
 	}
 }

node/expr/ternary.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -27,21 +24,23 @@ func NewTernary(condition node.Node, ifTrue node.Node, ifFalse node.Node) node.N
 	}
 }
 
-func (n Ternary) Print(out io.Writer, indent string) {
+func (n Ternary) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.condition != nil {
-		fmt.Fprintf(out, "\n%vcondition:", indent+"  ")
+		vv := v.Children("condition")
-		n.condition.Print(out, indent+"    ")
+		n.condition.Walk(vv)
 	}
 
 	if n.ifTrue != nil {
-		fmt.Fprintf(out, "\n%vifTrue:", indent+"  ")
+		vv := v.Children("ifTrue")
-		n.ifTrue.Print(out, indent+"    ")
+		n.ifTrue.Walk(vv)
 	}
 
 	if n.ifFalse != nil {
-		fmt.Fprintf(out, "\n%vifFalse:", indent+"  ")
+		vv := v.Children("ifFalse")
-		n.ifFalse.Print(out, indent+"    ")
+		n.ifFalse.Walk(vv)
 	}
 }

node/expr/unary_minus.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -23,11 +20,13 @@ func NewUnaryMinus(expression node.Node) node.Node {
 	}
 }
 
-func (n UnaryMinus) Print(out io.Writer, indent string) {
+func (n UnaryMinus) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.expr != nil {
-		fmt.Fprintf(out, "\n%vexpr:", indent+"  ")
+		vv := v.Children("expr")
-		n.expr.Print(out, indent+"    ")
+		n.expr.Walk(vv)
 	}
 }

node/expr/unary_plus.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -23,11 +20,13 @@ func NewUnaryPlus(expression node.Node) node.Node {
 	}
 }
 
-func (n UnaryPlus) Print(out io.Writer, indent string) {
+func (n UnaryPlus) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.expr != nil {
-		fmt.Fprintf(out, "\n%vexpr:", indent+"  ")
+		vv := v.Children("expr")
-		n.expr.Print(out, indent+"    ")
+		n.expr.Walk(vv)
 	}
 }

node/expr/variable.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -12,22 +9,24 @@ func (n Variable) Name() string {
 }
 
 type Variable struct {
-	name     string
+	name    string
-	variable node.Node
+	varName node.Node
 }
 
-func NewVariable(variable node.Node) node.Node {
+func NewVariable(varName node.Node) node.Node {
 	return Variable{
 		"Variable",
-		variable,
+		varName,
 	}
 }
 
-func (n Variable) Print(out io.Writer, indent string) {
+func (n Variable) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
-	if n.variable != nil {
+	if n.varName != nil {
-		fmt.Fprintf(out, "\n%vvariable:", indent+"  ")
+		vv := v.Children("varName")
-		n.variable.Print(out, indent+"    ")
+		n.varName.Walk(vv)
 	}
 }

node/expr/yield.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -25,16 +22,18 @@ func NewYield(key node.Node, value node.Node) node.Node {
 	}
 }
 
-func (n Yield) Print(out io.Writer, indent string) {
+func (n Yield) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.key != nil {
-		fmt.Fprintf(out, "\n%vkey:", indent+"  ")
+		vv := v.Children("key")
-		n.key.Print(out, indent+"    ")
+		n.key.Walk(vv)
 	}
 
 	if n.value != nil {
-		fmt.Fprintf(out, "\n%vvalue:", indent+"  ")
+		vv := v.Children("value")
-		n.value.Print(out, indent+"    ")
+		n.value.Walk(vv)
 	}
 }

node/expr/yield_from.go

@@ -1,9 +1,6 @@
 package expr
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -23,11 +20,13 @@ func NewYieldFrom(expression node.Node) node.Node {
 	}
 }
 
-func (n YieldFrom) Print(out io.Writer, indent string) {
+func (n YieldFrom) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.expr != nil {
-		fmt.Fprintf(out, "\n%vexpr:", indent+"  ")
+		vv := v.Children("expr")
-		n.expr.Print(out, indent+"    ")
+		n.expr.Walk(vv)
 	}
 }

node/identifier.go

@@ -1,9 +1,6 @@
 package node
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/token"
 )
 
@@ -23,7 +20,10 @@ func NewIdentifier(token token.Token) Node {
 	}
 }
 
-func (n Identifier) Print(out io.Writer, indent string) {
+func (n Identifier) Walk(v Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
-	fmt.Fprintf(out, "\n%vname: %q", indent+"  ", n.token.Value)
+		return
+	}
+
+	v.Scalar("token", n.token.Value)
 }

node/name/name.go

@@ -1,9 +1,6 @@
 package name
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 )
 
@@ -23,13 +20,15 @@ func NewName(parts []node.Node) node.Node {
 	}
 }
 
-func (n NameNode) Print(out io.Writer, indent string) {
+func (n NameNode) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.parts != nil {
-		fmt.Fprintf(out, "\n%vparts:", indent+"  ")
+		vv := v.Children("parts")
 		for _, nn := range n.parts {
-			nn.Print(out, indent+"    ")
+			nn.Walk(vv)
 		}
 	}
 }

node/name/name_part.go

@@ -1,14 +1,11 @@
 package name
 
 import (
-	"fmt"
-	"io"
-
 	"github.com/z7zmey/php-parser/node"
 	"github.com/z7zmey/php-parser/token"
 )
 
-func(n NamePart) Name() string {
+func (n NamePart) Name() string {
 	return "NamePart"
 }
 
@@ -24,6 +21,10 @@ func NewNamePart(token token.Token) node.Node {
 	}
 }
 
-func (n NamePart) Print(out io.Writer, indent string) {
+func (n NamePart) Walk(v node.Visitor) {
-	fmt.Fprintf(out, "\n%v%v [%d %d] %q", indent, n.name, n.token.StartLine, n.token.EndLine, n.token.Value)
+	if v.Visit(n) == false {
+		return
+	}
+
+	v.Scalar("token", n.token.Value)
 }

node/node.go

@@ -1,10 +1,6 @@
 package node
 
-import (
-	"io"
-)
-
 type Node interface {
 	Name() string
-	Print(out io.Writer, indent string)
+	Walk(v Visitor)
 }

node/nullable.go

@@ -1,10 +1,5 @@
 package node
 
-import (
-	"fmt"
-	"io"
-)
-
 type Nullable struct {
 	name string
 	expr Node
@@ -21,11 +16,13 @@ func NewNullable(expression Node) Node {
 	}
 }
 
-func (n Nullable) Print(out io.Writer, indent string) {
+func (n Nullable) Walk(v Visitor) {
-	fmt.Fprintf(out, "\n%v%v [- -]", indent, n.name)
+	if v.Visit(n) == false {
+		return
+	}
 
 	if n.expr != nil {
-		fmt.Fprintf(out, "\n%vexpr:", indent+"  ")
+		vv := v.Children("expr")
-		n.expr.Print(out, indent+"    ")
+		n.expr.Walk(vv)
 	}
 }