Improve ScanJsonNumber.

src/scanner.cc

 // Copyright 2010 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 498 matching lines @@
     }
   }
   literal.Complete();
   Advance();
   return Token::STRING;
 }
 
 
 Token::Value JsonScanner::ScanJsonNumber() {
   LiteralScope literal(this);
-  if (c0_ == '-') AddLiteralCharAdvance();
+  bool sign = (c0_ == '-');

[Lasse Reichstein, 2011/02/04 13:53:36]

Call the variable "negative". 
It's not obvious what "sign" being true means. 

[sandholm, 2011/02/04 14:26:37]

Done.

+
+  if (sign) AddLiteralCharAdvance();

[Lasse Reichstein, 2011/02/04 13:53:36]

I would prefer:
bool negative = false;
if (c0_ == '-') {
  negative = true;
  AddLiteralCharAdvance();
}

[sandholm, 2011/02/04 14:26:37]

Done.

   if (c0_ == '0') {
     AddLiteralCharAdvance();
     // Prefix zero is only allowed if it's the only digit before
     // a decimal point or exponent.
     if ('0' <= c0_ && c0_ <= '9') return Token::ILLEGAL;
   } else {
+    int i = 0;
+    int digits = 0;
     if (c0_ < '1' || c0_ > '9') return Token::ILLEGAL;
     do {
+      i = i * 10 + c0_ - '0';
+      digits++;
       AddLiteralCharAdvance();
     } while (c0_ >= '0' && c0_ <= '9');
+    if (c0_ != '.' && c0_ != 'e' && c0_ != 'E' && digits < 10) {
+      number = (sign ? -i : i);
+      return Token::NUMBER;
+    }
   }
   if (c0_ == '.') {
     AddLiteralCharAdvance();
     if (c0_ < '0' || c0_ > '9') return Token::ILLEGAL;
     do {
       AddLiteralCharAdvance();
     } while (c0_ >= '0' && c0_ <= '9');
   }
   if (AsciiAlphaToLower(c0_) == 'e') {
     AddLiteralCharAdvance();
     if (c0_ == '-' || c0_ == '+') AddLiteralCharAdvance();
     if (c0_ < '0' || c0_ > '9') return Token::ILLEGAL;
     do {
       AddLiteralCharAdvance();
     } while (c0_ >= '0' && c0_ <= '9');
   }
   literal.Complete();
+  ASSERT_NOT_NULL(next_.literal_chars);
+  number = StringToDouble(next_.literal_chars->ascii_literal(),
+                          NO_FLAGS,  // Hex, octal or trailing junk.
+                          OS::nan_value());
   return Token::NUMBER;
 }
 
 
 Token::Value JsonScanner::ScanJsonIdentifier(const char* text,
                                              Token::Value token) {
   LiteralScope literal(this);
   while (*text != '\0') {
     if (c0_ != *text) return Token::ILLEGAL;
     Advance();
     text++;
   }
   if (ScannerConstants::kIsIdentifierPart.get(c0_)) return Token::ILLEGAL;
   literal.Complete();
   return token;
 }
 
 
 
 } }  // namespace v8::internal