Adding compound assignments to the top-level compiler.

src/token.h

 // Copyright 2006-2008 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 48 matching lines @@
   T(LBRACE, "{", 0)                                                     \
   T(RBRACE, "}", 0)                                                     \
   T(COLON, ":", 0)                                                      \
   T(SEMICOLON, ";", 0)                                                  \
   T(PERIOD, ".", 0)                                                     \
   T(CONDITIONAL, "?", 3)                                                \
   T(INC, "++", 0)                                                       \
   T(DEC, "--", 0)                                                       \
                                                                         \
   /* Assignment operators. */                                           \
-  /* IsAssignmentOp() relies on this block of enum values */            \
-  /* being contiguous and sorted in the same order! */                  \
+  /* IsAssignmentOp() and Assignment::is_compound() relies on */        \
+  /* this block of enum values being contiguous and sorted in the */    \
+  /* same order! */                                                     \
   T(INIT_VAR, "=init_var", 2)  /* AST-use only. */                      \
   T(INIT_CONST, "=init_const", 2)  /* AST-use only. */                  \
   T(ASSIGN, "=", 2)                                                     \
   T(ASSIGN_BIT_OR, "|=", 2)                                             \
   T(ASSIGN_BIT_XOR, "^=", 2)                                            \
   T(ASSIGN_BIT_AND, "&=", 2)                                            \
   T(ASSIGN_SHL, "<<=", 2)                                               \
   T(ASSIGN_SAR, ">>=", 2)                                               \
   T(ASSIGN_SHR, ">>>=", 2)                                              \
   T(ASSIGN_ADD, "+=", 2)                                                \
@@ skipping 183 matching lines @@
 #ifdef DEBUG
   static const char* name_[NUM_TOKENS];
 #endif
   static const char* string_[NUM_TOKENS];
   static int8_t precedence_[NUM_TOKENS];
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_TOKEN_H_