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package ast
import "fmt"
// Visitor Enter method is invoked for each node encountered by Walk.
// If the result visitor w is not nil, Walk visits each of the children
// of node with the visitor v, followed by a call of the Exit method.
type Visitor interface {
Enter(n Node) (v Visitor)
Exit(n Node)
}
// Walk traverses an AST in depth-first order: It starts by calling
// v.Enter(node); node must not be nil. If the visitor v returned by
// v.Enter(node) is not nil, Walk is invoked recursively with visitor
// v for each of the non-nil children of node, followed by a call
// of v.Exit(node).
func Walk(v Visitor, n Node) {
if n == nil {
return
}
if v = v.Enter(n); v == nil {
return
}
defer v.Exit(n)
switch n := n.(type) {
case *ArrayLiteral:
if n != nil {
for _, ex := range n.Value {
Walk(v, ex)
}
}
case *AssignExpression:
if n != nil {
Walk(v, n.Left)
Walk(v, n.Right)
}
case *BadExpression:
case *BinaryExpression:
if n != nil {
Walk(v, n.Left)
Walk(v, n.Right)
}
case *BlockStatement:
if n != nil {
for _, s := range n.List {
Walk(v, s)
}
}
case *BooleanLiteral:
case *BracketExpression:
if n != nil {
Walk(v, n.Left)
Walk(v, n.Member)
}
case *BranchStatement:
if n != nil {
Walk(v, n.Label)
}
case *CallExpression:
if n != nil {
Walk(v, n.Callee)
for _, a := range n.ArgumentList {
Walk(v, a)
}
}
case *CaseStatement:
if n != nil {
Walk(v, n.Test)
for _, c := range n.Consequent {
Walk(v, c)
}
}
case *CatchStatement:
if n != nil {
Walk(v, n.Parameter)
Walk(v, n.Body)
}
case *ConditionalExpression:
if n != nil {
Walk(v, n.Test)
Walk(v, n.Consequent)
Walk(v, n.Alternate)
}
case *DebuggerStatement:
case *DoWhileStatement:
if n != nil {
Walk(v, n.Test)
Walk(v, n.Body)
}
case *DotExpression:
if n != nil {
Walk(v, n.Left)
}
case *EmptyExpression:
case *EmptyStatement:
case *ExpressionStatement:
if n != nil {
Walk(v, n.Expression)
}
case *ForInStatement:
if n != nil {
Walk(v, n.Into)
Walk(v, n.Source)
Walk(v, n.Body)
}
case *ForStatement:
if n != nil {
Walk(v, n.Initializer)
Walk(v, n.Update)
Walk(v, n.Test)
Walk(v, n.Body)
}
case *FunctionLiteral:
if n != nil {
Walk(v, n.Name)
for _, p := range n.ParameterList.List {
Walk(v, p)
}
Walk(v, n.Body)
}
case *FunctionStatement:
if n != nil {
Walk(v, n.Function)
}
case *Identifier:
case *IfStatement:
if n != nil {
Walk(v, n.Test)
Walk(v, n.Consequent)
Walk(v, n.Alternate)
}
case *LabelledStatement:
if n != nil {
Walk(v, n.Statement)
}
case *NewExpression:
if n != nil {
Walk(v, n.Callee)
for _, a := range n.ArgumentList {
Walk(v, a)
}
}
case *NullLiteral:
case *NumberLiteral:
case *ObjectLiteral:
if n != nil {
for _, p := range n.Value {
Walk(v, p.Value)
}
}
case *Program:
if n != nil {
for _, b := range n.Body {
Walk(v, b)
}
}
case *RegExpLiteral:
case *ReturnStatement:
if n != nil {
Walk(v, n.Argument)
}
case *SequenceExpression:
if n != nil {
for _, e := range n.Sequence {
Walk(v, e)
}
}
case *StringLiteral:
case *SwitchStatement:
if n != nil {
Walk(v, n.Discriminant)
for _, c := range n.Body {
Walk(v, c)
}
}
case *ThisExpression:
case *ThrowStatement:
if n != nil {
Walk(v, n.Argument)
}
case *TryStatement:
if n != nil {
Walk(v, n.Body)
Walk(v, n.Catch)
Walk(v, n.Finally)
}
case *UnaryExpression:
if n != nil {
Walk(v, n.Operand)
}
case *VariableExpression:
if n != nil {
Walk(v, n.Initializer)
}
case *VariableStatement:
if n != nil {
for _, e := range n.List {
Walk(v, e)
}
}
case *WhileStatement:
if n != nil {
Walk(v, n.Test)
Walk(v, n.Body)
}
case *WithStatement:
if n != nil {
Walk(v, n.Object)
Walk(v, n.Body)
}
default:
panic(fmt.Sprintf("Walk: unexpected node type %T", n))
}
}
|
