Implement symbol literals in the VM compiler

runtime/vm/scanner.cc

 // 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.
 
 #include "vm/scanner.h"
 
 #include "platform/assert.h"
 #include "vm/flags.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
@@ skipping 382 matching lines @@
 
 void Scanner::SkipLine() {
   while (c0_ != '\n' && c0_ != '\0') {
     ReadChar();
   }
 }
 
 
 void Scanner::ScanScriptTag() {
   ReadChar();
-  if (c0_ == '!') {
-    Recognize(Token::kSCRIPTTAG);
-    // The script tag extends to the end of the line. Just treat this
-    // similar to a line comment.
-    SkipLine();
-    return;
-  } else {
-    ErrorMsg("unexpected character: '#'");
-    SkipLine();
-    return;
-  }
+  ASSERT(c0_ == '!');
+  Recognize(Token::kSCRIPTTAG);
+  // The script tag extends to the end of the line. Just treat this
+  // similar to a line comment.
+  SkipLine();
 }
 
 
 void Scanner::ScanLiteralString(bool is_raw) {
   ASSERT(!IsScanningString());
   ASSERT(c0_ == '"' || c0_ == '\'');
 
   // Entering string scanning mode.
   BeginStringLiteral(c0_);
   string_is_multiline_ = (LookaheadChar(1) == c0_) &&
@@ skipping 406 matching lines @@
           ScanIdent();
         }
         break;
 
       case '"':
       case '\'':
         ScanLiteralString(false);
         break;
 
       case '#':
-        ScanScriptTag();
+        if (LookaheadChar(1) == '!') {
+          ScanScriptTag();
+        } else {
+          Recognize(Token::kHASH);
+        }
         break;
 
       default:
         if (IsIdentStartChar(c0_)) {
           ScanIdent();
         } else if (IsDecimalDigit(c0_)) {
           ScanNumber(false);
         } else {
           char msg[128];
           char utf8_char[5];
@@ skipping 99 matching lines @@
               "%c%#" Px "", kPrivateKeySeparator, key_value);
   const String& result = String::Handle(String::New(private_key, Heap::kOld));
   return result.raw();
 }
 
 
 void Scanner::InitOnce() {
 }
 
 }  // namespace dart