null-aware operators in the VM

runtime/vm/ast.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_AST_H_
 #define VM_AST_H_
 
 #include "platform/assert.h"
 #include "vm/allocation.h"
 #include "vm/growable_array.h"
@@ skipping 1403 matching lines @@
   const Class& super_class_;
   DISALLOW_IMPLICIT_CONSTRUCTORS(StoreIndexedNode);
 };
 
 
 class InstanceCallNode : public AstNode {
  public:
   InstanceCallNode(intptr_t token_pos,
                    AstNode* receiver,
                    const String& function_name,
-                   ArgumentListNode* arguments)
+                   ArgumentListNode* arguments,
+                   bool is_conditional = false)
       : AstNode(token_pos),
         receiver_(receiver),
         function_name_(function_name),
-        arguments_(arguments) {
+        arguments_(arguments),
+        is_conditional_(is_conditional) {
     ASSERT(receiver_ != NULL);
     ASSERT(function_name_.IsNotTemporaryScopedHandle());
     ASSERT(function_name_.IsSymbol());
     ASSERT(arguments_ != NULL);
   }
 
   AstNode* receiver() const { return receiver_; }
   const String& function_name() const { return function_name_; }
   ArgumentListNode* arguments() const { return arguments_; }
+  bool is_conditional() const { return is_conditional_; }
 
   virtual void VisitChildren(AstNodeVisitor* visitor) const {
     receiver()->Visit(visitor);
     arguments()->Visit(visitor);
   }
 
   DECLARE_COMMON_NODE_FUNCTIONS(InstanceCallNode);
 
  private:
   AstNode* receiver_;
   const String& function_name_;
   ArgumentListNode* arguments_;
+  const bool is_conditional_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(InstanceCallNode);
 };
 
 
 class InstanceGetterNode : public AstNode {
  public:
   InstanceGetterNode(intptr_t token_pos,
                      AstNode* receiver,
-                     const String& field_name)
+                     const String& field_name,
+                     bool is_conditional = false)
       : AstNode(token_pos),
         receiver_(receiver),
-        field_name_(field_name) {
+        field_name_(field_name),
+        is_conditional_(is_conditional) {
     ASSERT(receiver_ != NULL);
     ASSERT(field_name_.IsNotTemporaryScopedHandle());
     ASSERT(field_name_.IsSymbol());
   }
 
   AstNode* receiver() const { return receiver_; }
   const String& field_name() const { return field_name_; }
+  bool is_conditional() const { return is_conditional_; }
 
   virtual void VisitChildren(AstNodeVisitor* visitor) const {
     receiver()->Visit(visitor);
   }
 
   virtual AstNode* MakeAssignmentNode(AstNode* rhs);
 
   virtual bool IsPotentiallyConst() const;
   virtual const Instance* EvalConstExpr() const;
 
   DECLARE_COMMON_NODE_FUNCTIONS(InstanceGetterNode);
 
  private:
   AstNode* receiver_;
   const String& field_name_;
+  const bool is_conditional_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(InstanceGetterNode);
 };
 
 
 class InstanceSetterNode : public AstNode {
  public:
   InstanceSetterNode(intptr_t token_pos,
                      AstNode* receiver,
                      const String& field_name,
-                     AstNode* value)
+                     AstNode* value,
+                     bool is_conditional = false)
       : AstNode(token_pos),
         receiver_(receiver),
         field_name_(field_name),
-        value_(value) {
+        value_(value),
+        is_conditional_(is_conditional) {
     ASSERT(receiver_ != NULL);
     ASSERT(value_ != NULL);
     ASSERT(field_name_.IsZoneHandle());
     ASSERT(field_name_.IsSymbol());
   }
 
   AstNode* receiver() const { return receiver_; }
   const String& field_name() const { return field_name_; }
   AstNode* value() const { return value_; }
+  bool is_conditional() const { return is_conditional_; }
 
   virtual void VisitChildren(AstNodeVisitor* visitor) const {
     receiver()->Visit(visitor);
     value()->Visit(visitor);
   }
 
   DECLARE_COMMON_NODE_FUNCTIONS(InstanceSetterNode);
 
  private:
   AstNode* receiver_;
   const String& field_name_;
   AstNode* value_;
+  const bool is_conditional_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(InstanceSetterNode);
 };
 
 
 class InitStaticFieldNode : public AstNode {
  public:
   InitStaticFieldNode(intptr_t token_pos, const Field& field)
       : AstNode(token_pos), field_(field) {
     ASSERT(field_.IsZoneHandle());
@@ skipping 468 matching lines @@
   const intptr_t try_index_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(InlinedFinallyNode);
 };
 
 }  // namespace dart
 
 #undef DECLARE_COMMON_NODE_FUNCTIONS
 
 #endif  // VM_AST_H_