Templatize AstVisitor with its subclass

src/ast/prettyprinter.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_AST_PRETTYPRINTER_H_
 #define V8_AST_PRETTYPRINTER_H_
 
 #include "src/allocation.h"
 #include "src/ast/ast.h"
 #include "src/base/compiler-specific.h"
 
 namespace v8 {
 namespace internal {
 
-class CallPrinter : public AstVisitor {
+class CallPrinter final : public AstVisitor<CallPrinter> {
  public:
   explicit CallPrinter(Isolate* isolate, bool is_builtin);
-  virtual ~CallPrinter();
+  ~CallPrinter();
 
   // The following routine prints the node with position |position| into a
   // string. The result string is alive as long as the CallPrinter is alive.
   const char* Print(FunctionLiteral* program, int position);
 
   void PRINTF_FORMAT(2, 3) Print(const char* format, ...);
 
   void Find(AstNode* node, bool print = false);
 
 // Individual nodes
-#define DECLARE_VISIT(type) void Visit##type(type* node) override;
+#define DECLARE_VISIT(type) void Visit##type(type* node);
   AST_NODE_LIST(DECLARE_VISIT)
 #undef DECLARE_VISIT
 
  private:
   void Init();
   Isolate* isolate_;
   char* output_;  // output string buffer
   int size_;      // output_ size
   int pos_;       // current printing position
   int position_;  // position of ast node to print
   bool found_;
   bool done_;
   bool is_builtin_;
 
   DEFINE_AST_VISITOR_SUBCLASS_MEMBERS();
 
  protected:
   void PrintLiteral(Object* value, bool quote);
   void PrintLiteral(const AstRawString* value, bool quote);
   void FindStatements(ZoneList<Statement*>* statements);
   void FindArguments(ZoneList<Expression*>* arguments);
 };
 
 
 #ifdef DEBUG
 
-// Prints the AST structure
-class AstPrinter : public AstVisitor {
+class AstPrinter final : public AstVisitor<AstPrinter> {
  public:
   explicit AstPrinter(Isolate* isolate);
-  virtual ~AstPrinter();
+  ~AstPrinter();
 
   // The following routines print a node into a string.
-  // The result string is alive as long as the PrettyPrinter is alive.
+  // The result string is alive as long as the AstPrinter is alive.
   const char* Print(AstNode* node);
   const char* PrintProgram(FunctionLiteral* program);
 
   void PRINTF_FORMAT(2, 3) Print(const char* format, ...);
 
   // Print a node to stdout.
   static void PrintOut(Isolate* isolate, AstNode* node);
 
   // Individual nodes
-#define DECLARE_VISIT(type) void Visit##type(type* node) override;
+#define DECLARE_VISIT(type) void Visit##type(type* node);
   AST_NODE_LIST(DECLARE_VISIT)
 #undef DECLARE_VISIT
 
  private:
   friend class IndentedScope;
 
   void Init();
 
   void PrintLabels(ZoneList<const AstRawString*>* labels);
   void PrintLiteral(const AstRawString* value, bool quote);
@@ skipping 25 matching lines @@
   int pos_;       // current printing position
   int indent_;
 };
 
 #endif  // DEBUG
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_AST_PRETTYPRINTER_H_