text: // Copyright 2012 the V8 project authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #ifndef V8_TOKEN_H_
  #define V8_TOKEN_H_
  
  #include "src/base/logging.h"
  
  namespace v8 {
  namespace internal {
  
  // TOKEN_LIST takes a list of 3 macros M, all of which satisfy the
  // same signature M(name, string, precedence), where name is the
  // symbolic token name, string is the corresponding syntactic symbol
  // (or NULL, for literals), and precedence is the precedence (or 0).
  // The parameters are invoked for token categories as follows:
  //
  //   T: Non-keyword tokens
  //   K: Keyword tokens
  
  // IGNORE_TOKEN is a convenience macro that can be supplied as
  // an argument (at any position) for a TOKEN_LIST call. It does
  // nothing with tokens belonging to the respective category.
  
  #define IGNORE_TOKEN(name, string, precedence)
  
  #define TOKEN_LIST(T, K)                                             \
    /* End of source indicator. */                                     \
    T(EOS, "EOS", 0)                                                   \
                                                                       \
    /* Punctuators (ECMA-262, section 7.7, page 15). */                \
    T(LPAREN, "(", 0)                                                  \
    T(RPAREN, ")", 0)                                                  \
    T(LBRACK, "[", 0)                                                  \
    T(RBRACK, "]", 0)                                                  \
    T(LBRACE, "{", 0)                                                  \
    T(RBRACE, "}", 0)                                                  \
    T(COLON, ":", 0)                                                   \
    T(SEMICOLON, ";", 0)                                               \
    T(PERIOD, ".", 0)                                                  \
    T(CONDITIONAL, "?", 3)                                             \
    T(INC, "++", 0)                                                    \
    T(DEC, "--", 0)                                                    \
    T(ARROW, "=>", 0)                                                  \
                                                                       \
    /* Assignment operators. */                                        \
    /* 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_LET, "=init_let", 2)                   /* AST-use only. */  \
    T(INIT_CONST, "=init_const", 2)               /* AST-use only. */  \
    T(INIT_CONST_LEGACY, "=init_const_legacy", 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)                                             \
    T(ASSIGN_SUB, "-=", 2)                                             \
    T(ASSIGN_MUL, "*=", 2)                                             \
    T(ASSIGN_DIV, "/=", 2)                                             \
    T(ASSIGN_MOD, "%=", 2)                                             \
                                                                       \
    /* Binary operators sorted by precedence. */                       \
    /* IsBinaryOp() relies on this block of enum values */             \
    /* being contiguous and sorted in the same order! */               \
    T(COMMA, ",", 1)                                                   \
    T(OR, "||", 4)                                                     \
    T(AND, "&&", 5)                                                    \
    T(BIT_OR, "|", 6)                                                  \
    T(BIT_XOR, "^", 7)                                                 \
    T(BIT_AND, "&", 8)                                                 \
    T(SHL, "<<", 11)                                                   \
    T(SAR, ">>", 11)                                                   \
    T(SHR, ">>>", 11)                                                  \
    T(ROR, "rotate right", 11) /* only used by Crankshaft */           \
    T(ADD, "+", 12)                                                    \
    T(SUB, "-", 12)                                                    \
    T(MUL, "*", 13)                                                    \
    T(DIV, "/", 13)                                                    \
    T(MOD, "%", 13)                                                    \
                                                                       \
    /* Compare operators sorted by precedence. */                      \
    /* IsCompareOp() relies on this block of enum values */            \
    /* being contiguous and sorted in the same order! */               \
    T(EQ, "==", 9)                                                     \
    T(NE, "!=", 9)                                                     \
    T(EQ_STRICT, "===", 9)                                             \
    T(NE_STRICT, "!==", 9)                                             \
    T(LT, "<", 10)                                                     \
    T(GT, ">", 10)                                                     \
    T(LTE, "<=", 10)                                                   \
    T(GTE, ">=", 10)                                                   \
    K(INSTANCEOF, "instanceof", 10)                                    \
    K(IN, "in", 10)                                                    \
                                                                       \
    /* Unary operators. */                                             \
    /* IsUnaryOp() relies on this block of enum values */              \
    /* being contiguous and sorted in the same order! */               \
    T(NOT, "!", 0)                                                     \
    T(BIT_NOT, "~", 0)                                                 \
    K(DELETE, "delete", 0)                                             \
    K(TYPEOF, "typeof", 0)                                             \
    K(VOID, "void", 0)                                                 \
                                                                       \
    /* Keywords (ECMA-262, section 7.5.2, page 13). */                 \
    K(BREAK, "break", 0)                                               \
    K(CASE, "case", 0)                                                 \
    K(CATCH, "catch", 0)                                               \
    K(CONTINUE, "continue", 0)                                         \
    K(DEBUGGER, "debugger", 0)                                         \
    K(DEFAULT, "default", 0)                                           \
    /* DELETE */                                                       \
    K(DO, "do", 0)                                                     \
    K(ELSE, "else", 0)                                                 \
    K(FINALLY, "finally", 0)                                           \
    K(FOR, "for", 0)                                                   \
    K(FUNCTION, "function", 0)                                         \
    K(IF, "if", 0)                                                     \
    /* IN */                                                           \
    /* INSTANCEOF */                                                   \
    K(NEW, "new", 0)                                                   \
    K(RETURN, "return", 0)                                             \
    K(SWITCH, "switch", 0)                                             \
    K(THIS, "this", 0)                                                 \
    K(THROW, "throw", 0)                                               \
    K(TRY, "try", 0)                                                   \
    /* TYPEOF */                                                       \
    K(VAR, "var", 0)                                                   \
    /* VOID */                                                         \
    K(WHILE, "while", 0)                                               \
    K(WITH, "with", 0)                                                 \
                                                                       \
    /* Literals (ECMA-262, section 7.8, page 16). */                   \
    K(NULL_LITERAL, "null", 0)                                         \
    K(TRUE_LITERAL, "true", 0)                                         \
    K(FALSE_LITERAL, "false", 0)                                       \
    T(NUMBER, NULL, 0)                                                 \
    T(STRING, NULL, 0)                                                 \
                                                                       \
    /* Identifiers (not keywords or future reserved words). */         \
    T(IDENTIFIER, NULL, 0)                                             \
                                                                       \
    /* Future reserved words (ECMA-262, section 7.6.1.2). */           \
    T(FUTURE_RESERVED_WORD, NULL, 0)                                   \
    T(FUTURE_STRICT_RESERVED_WORD, NULL, 0)                            \
    K(CONST, "const", 0)                                               \
    K(EXPORT, "export", 0)                                             \
    K(IMPORT, "import", 0)                                             \
    K(LET, "let", 0)                                                   \
    K(YIELD, "yield", 0)                                               \
                                                                       \
    /* Illegal token - not able to scan. */                            \
    T(ILLEGAL, "ILLEGAL", 0)                                           \
                                                                       \
    /* Scanner-internal use only. */                                   \
    T(WHITESPACE, NULL, 0)
  
  
  class Token {
   public:
    // All token values.
  #define T(name, string, precedence) name,
    enum Value {
      TOKEN_LIST(T, T)
      NUM_TOKENS
    };
  #undef T
  
    // Returns a string corresponding to the C++ token name
    // (e.g. "LT" for the token LT).
    static const char* Name(Value tok) {
      DCHECK(tok < NUM_TOKENS);  // tok is unsigned
      return name_[tok];
    }
  
    // Predicates
    static bool IsKeyword(Value tok) {
      return token_type[tok] == 'K';
    }
  
    static bool IsAssignmentOp(Value tok) {
      return INIT_VAR <= tok && tok <= ASSIGN_MOD;
    }
  
    static bool IsBinaryOp(Value op) {
      return COMMA <= op && op <= MOD;
    }
  
    static bool IsTruncatingBinaryOp(Value op) {
      return BIT_OR <= op && op <= ROR;
    }
  
    static bool IsCompareOp(Value op) {
      return EQ <= op && op <= IN;
    }
  
    static bool IsOrderedRelationalCompareOp(Value op) {
      return op == LT || op == LTE || op == GT || op == GTE;
    }
  
    static bool IsEqualityOp(Value op) {
      return op == EQ || op == EQ_STRICT;
    }
  
    static bool IsInequalityOp(Value op) {
      return op == NE || op == NE_STRICT;
    }
  
    static bool IsArithmeticCompareOp(Value op) {
      return IsOrderedRelationalCompareOp(op) ||
          IsEqualityOp(op) || IsInequalityOp(op);
    }
  
    static Value NegateCompareOp(Value op) {
      DCHECK(IsArithmeticCompareOp(op));
      switch (op) {
        case EQ: return NE;
        case NE: return EQ;
        case EQ_STRICT: return NE_STRICT;
        case NE_STRICT: return EQ_STRICT;
        case LT: return GTE;
        case GT: return LTE;
        case LTE: return GT;
        case GTE: return LT;
        default:
          UNREACHABLE();
          return op;
      }
    }
  
    static Value ReverseCompareOp(Value op) {
      DCHECK(IsArithmeticCompareOp(op));
      switch (op) {
        case EQ: return EQ;
        case NE: return NE;
        case EQ_STRICT: return EQ_STRICT;
        case NE_STRICT: return NE_STRICT;
        case LT: return GT;
        case GT: return LT;
        case LTE: return GTE;
        case GTE: return LTE;
        default:
          UNREACHABLE();
          return op;
      }
    }
  
    static bool IsBitOp(Value op) {
      return (BIT_OR <= op && op <= SHR) || op == BIT_NOT;
    }
  
    static bool IsUnaryOp(Value op) {
      return (NOT <= op && op <= VOID) || op == ADD || op == SUB;
    }
  
    static bool IsCountOp(Value op) {
      return op == INC || op == DEC;
    }
  
    static bool IsShiftOp(Value op) {
      return (SHL <= op) && (op <= SHR);
    }
  
    // Returns a string corresponding to the JS token string
    // (.e., "<" for the token LT) or NULL if the token doesn't
    // have a (unique) string (e.g. an IDENTIFIER).
    static const char* String(Value tok) {
      DCHECK(tok < NUM_TOKENS);  // tok is unsigned.
      return string_[tok];
    }
  
    // Returns the precedence > 0 for binary and compare
    // operators; returns 0 otherwise.
    static int Precedence(Value tok) {
      DCHECK(tok < NUM_TOKENS);  // tok is unsigned.
      return precedence_[tok];
    }
  
   private:
    static const char* const name_[NUM_TOKENS];
    static const char* const string_[NUM_TOKENS];
    static const int8_t precedence_[NUM_TOKENS];
    static const char token_type[NUM_TOKENS];
  };
  
  } }  // namespace v8::internal
  
  #endif  // V8_TOKEN_H_
  