Implement type cast in the VM.

runtime/vm/token.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_TOKEN_H_
 #define VM_TOKEN_H_
 
 #include "platform/assert.h"
 
 namespace dart {
 
 //  Operator precedence table
 //
 //  13  multiplicative  * / ~/ %
 //  12  additive        + -
 //  11  shift           << >>
-//  10  relational      >= > <= < is
+//  10  relational      >= > <= < is as
 //   9  equality        == != === !==
 //   8  bitwise and     &
 //   7  bitwise xor     ^
 //   6  bitwise or      |
 //   5  logical and     &&
 //   4  logical or      ||
 //   3  conditional     ?
 //   2  assignment      = *= /= ~/= %= += -= <<= >>= &= ^= |=
 //   1  comma           ,
 
@@ skipping 71 matching lines @@
                                                                                \
   /* Relational operators.                             */                      \
   /* Please update IsRelationalOperator() if you make  */                      \
   /* any changes to this block.                        */                      \
   TOK(kLT, "<", 10, kNoAttribute)                                              \
   TOK(kGT, ">", 10, kNoAttribute)                                              \
   TOK(kLTE, "<=", 10, kNoAttribute)                                            \
   TOK(kGTE, ">=", 10, kNoAttribute)                                            \
                                                                                \
   /* Internal token for !(expr is Type) negative type test operator */         \
-  TOK(kISNOT, "", 0, kNoAttribute)                                             \
+  TOK(kISNOT, "", 10, kNoAttribute)                                            \
+                                                                               \
+  /* Internal token for (expr as Type) type cast operator */                   \
+  TOK(kAS, "", 10, kNoAttribute)                                               \
                                                                                \
   TOK(kINDEX, "[]", 0, kNoAttribute)                                           \
   TOK(kASSIGN_INDEX, "[]=", 0, kNoAttribute)                                   \
                                                                                \
   TOK(kIDENT, "", 0, kNoAttribute)                                             \
   TOK(kSTRING, "", 0, kNoAttribute)                                            \
   TOK(kINTEGER, "", 0, kNoAttribute)                                           \
   TOK(kDOUBLE, "", 0, kNoAttribute)                                            \
                                                                                \
   TOK(kINTERPOL_VAR, "", 0, kNoAttribute)                                      \
@@ skipping 85 matching lines @@
   }
 
   static bool IsRelationalOperator(Kind tok) {
     return kLT <= tok && tok <= kGTE;
   }
 
   static bool IsEqualityOperator(Kind tok) {
     return kEQ <= tok && tok <= kNE_STRICT;
   }
 
-  static bool IsInstanceofOperator(Kind tok) {
+  static bool IsTypeTestOperator(Kind tok) {
     return (tok == kIS) || (tok == kISNOT);
   }
 
+  static bool IsTypeCastOperator(Kind tok) {
+    return tok == kAS;
+  }
+
   static bool IsPseudoKeyword(Kind tok) {
     return (Attributes(tok) & kPseudoKeyword) != 0;
   }
 
   static bool IsKeyword(Kind tok) {
     return (Attributes(tok) & kKeyword) != 0;
   }
 
   static bool IsIdentifier(Kind tok) {
     return (tok == kIDENT) || IsPseudoKeyword(tok);
@@ skipping 46 matching lines @@
   static const char* name_[];
   static const char* tok_str_[];
   static const uint8_t precedence_[];
   static const Attribute attributes_[];
 };
 
 
 }  // namespace dart
 
 #endif  // VM_TOKEN_H_