Parser / PreParser unification: Add docs.

src/parser.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 390 matching lines @@
 
 // ----------------------------------------------------------------------------
 // JAVASCRIPT PARSING
 
 class Parser;
 class SingletonLogger;
 
 class ParserTraits {
  public:
   struct Type {
+    // TODO(marja): To be removed. The Traits object should contain all the data
+    // it needs.
     typedef v8::internal::Parser* Parser;
 
-    // Types used by FunctionState and BlockState.
+    // Used by FunctionState and BlockState.
     typedef v8::internal::Scope Scope;
-    typedef AstNodeFactory<AstConstructionVisitor> Factory;
     typedef Variable GeneratorVariable;
     typedef v8::internal::Zone Zone;
 
     // Return types for traversing functions.
     typedef Handle<String> Identifier;
     typedef v8::internal::Expression* Expression;
     typedef v8::internal::FunctionLiteral* FunctionLiteral;
     typedef v8::internal::Literal* Literal;
     typedef ObjectLiteral::Property* ObjectLiteralProperty;
     typedef ZoneList<v8::internal::Expression*>* ExpressionList;
     typedef ZoneList<ObjectLiteral::Property*>* PropertyList;
+
+    // For constructing objects returned by the traversing functions.
+    typedef AstNodeFactory<AstConstructionVisitor> Factory;
   };
 
   explicit ParserTraits(Parser* parser) : parser_(parser) {}
 
   // Custom operations executed when FunctionStates are created and destructed.
   template<typename FunctionState>
   static void SetUpFunctionState(FunctionState* function_state, Zone* zone) {
     Isolate* isolate = zone->isolate();
     function_state->isolate_ = isolate;
     function_state->saved_ast_node_id_ = isolate->ast_node_id();
@@ skipping 372 matching lines @@
  private:
   static const int kLiteralTypeSlot = 0;
   static const int kElementsSlot = 1;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(CompileTimeValue);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_PARSER_H_