Implement handling of arrow functions in the parser

src/ast.h

Index: src/ast.h
diff --git a/src/ast.h b/src/ast.h
index 23f9eef477a9a318769ad67256b650e23ca11372..579082cd6ae42f40c88b0b4623631e9e3604091c 100644
--- a/src/ast.h
+++ b/src/ast.h
@@ -344,6 +344,17 @@ class Expression : public AstNode {
   Bounds bounds() const { return bounds_; }
   void set_bounds(Bounds bounds) { bounds_ = bounds; }
 
+  // Whether the expression is parenthesized
+  unsigned parenthesization_level() const { return parenthesization_level_; }
+  bool is_parenthesized() const { return parenthesization_level_ > 0; }
+  void set_is_parenthesized(bool value) {

[marja, 2014/06/26 14:38:13]

Afaics this is never called with false (which would be a weird thing anyway...
like, we have increased the parenthization level before and then we suddenly
decide it's not parenthesized after all).

So you could call this increase_parenthesization_level() instead.

+    if (value) {
+      ++parenthesization_level_;
+    } else {
+      parenthesization_level_ = 0;
+    }
+  }
+
   // Type feedback information for assignments and properties.
   virtual bool IsMonomorphic() {
     UNREACHABLE();
@@ -370,6 +381,7 @@ class Expression : public AstNode {
       : AstNode(pos),
         zone_(zone),
         bounds_(Bounds::Unbounded(zone)),
+        parenthesization_level_(0),
         id_(GetNextId(zone)),
         test_id_(GetNextId(zone)) {}
   void set_to_boolean_types(byte types) { to_boolean_types_ = types; }
@@ -379,6 +391,7 @@ class Expression : public AstNode {
  private:
   Bounds bounds_;
   byte to_boolean_types_;
+  unsigned parenthesization_level_;
 
   const BailoutId id_;
   const TypeFeedbackId test_id_;