[es7] implement exponentiation operator proposal

src/parsing/parser-base.h

Index: src/parsing/parser-base.h
diff --git a/src/parsing/parser-base.h b/src/parsing/parser-base.h
index dc67e536c8e0eb76f9921bd712fa9fbc0ddb0e58..9c3d92c7d1c9f7f53c68bc0217c114c098668e06 100644
--- a/src/parsing/parser-base.h
+++ b/src/parsing/parser-base.h
@@ -121,6 +121,12 @@ class ParserBase : public Traits {
   bool allow_##name() const { return allow_##name##_; } \
   void set_allow_##name(bool allow) { allow_##name##_ = allow; }
 
+#define SCANNER_ACCESSORS(name)                                  \
+  bool allow_##name() const { return scanner_->allow_##name(); } \
+  void set_allow_##name(bool allow) {                            \
+    return scanner_->set_allow_##name(allow);                    \
+  }
+
   ALLOW_ACCESSORS(lazy);
   ALLOW_ACCESSORS(natives);
   ALLOW_ACCESSORS(harmony_sloppy);
@@ -131,6 +137,7 @@ class ParserBase : public Traits {
   ALLOW_ACCESSORS(harmony_do_expressions);
   ALLOW_ACCESSORS(harmony_function_name);
   ALLOW_ACCESSORS(harmony_function_sent);
+  SCANNER_ACCESSORS(harmony_exponentiation_operator);
 #undef ALLOW_ACCESSORS
 
   uintptr_t stack_limit() const { return stack_limit_; }
@@ -2010,6 +2017,11 @@ ParserBase<Traits>::ParseAssignmentExpression(bool accept_IN,
     Traits::SetFunctionNameFromIdentifierRef(right, expression);
   }
 
+  if (op == Token::ASSIGN_EXP) {
+    DCHECK(!is_destructuring_assignment);
+    return Traits::RewriteAssignExponentiation(expression, right, pos);
+  }
+
   ExpressionT result = factory()->NewAssignment(op, expression, right, pos);
 
   if (is_destructuring_assignment) {
@@ -2119,8 +2131,11 @@ ParserBase<Traits>::ParseBinaryExpression(int prec, bool accept_IN,
       ArrowFormalParametersUnexpectedToken(classifier);
       Token::Value op = Next();
       int pos = position();
+
+      const bool is_right_associative = op == Token::EXP;
+      const int next_prec = is_right_associative ? prec1 : prec1 + 1;
       ExpressionT y =
-          ParseBinaryExpression(prec1 + 1, accept_IN, classifier, CHECK_OK);
+          ParseBinaryExpression(next_prec, accept_IN, classifier, CHECK_OK);
       Traits::RewriteNonPattern(classifier, CHECK_OK);
 
       if (this->ShortcutNumericLiteralBinaryExpression(&x, y, op, pos,
@@ -2148,6 +2163,9 @@ ParserBase<Traits>::ParseBinaryExpression(int prec, bool accept_IN,
             x = factory()->NewUnaryOperation(Token::NOT, x, pos);
           }
         }
+
+      } else if (op == Token::EXP) {
+        x = Traits::RewriteExponentiation(x, y, pos);
       } else {
         // We have a "normal" binary operation.
         x = factory()->NewBinaryOperation(op, x, y, pos);
@@ -2193,6 +2211,12 @@ ParserBase<Traits>::ParseUnaryExpression(ExpressionClassifier* classifier,
       }
     }
 
+    if (peek() == Token::EXP) {
+      ReportUnexpectedToken(Next());
+      *ok = false;
+      return this->EmptyExpression();
+    }
+
     // Allow Traits do rewrite the expression.
     return this->BuildUnaryExpression(expression, op, pos, factory());
   } else if (Token::IsCountOp(op)) {