Java Token.NEG属性代码示例

/**
 * Returns true if this is an immutable value.
 */
static boolean isImmutableValue(Node n) {
  switch (n.getType()) {
    case Token.STRING:
    case Token.NUMBER:
    case Token.NULL:
    case Token.TRUE:
    case Token.FALSE:
    case Token.VOID:
      return true;
    case Token.NEG:
      return isImmutableValue(n.getFirstChild());
    case Token.NAME:
      String name = n.getString();
      // We assume here that programs don't change the value of the keyword
      // undefined to something other than the value undefined.
      return "undefined".equals(name)
          || "Infinity".equals(name)
          || "NaN".equals(name);
  }

  return false;
}
 

/**
 * Determines whether the given value may be assigned to a define.
 *
 * @param val The value being assigned.
 * @param defines The list of names of existing defines.
 */
static boolean isValidDefineValue(Node val, Set<String> defines) {
  switch (val.getType()) {
    case Token.STRING:
    case Token.NUMBER:
    case Token.TRUE:
    case Token.FALSE:
      return true;

    // Single operators are valid if the child is valid.
    case Token.BITAND:
    case Token.BITNOT:
    case Token.BITOR:
    case Token.BITXOR:
    case Token.NOT:
    case Token.NEG:
      return isValidDefineValue(val.getFirstChild(), defines);

    // Names are valid if and only if they are defines themselves.
    case Token.NAME:
    case Token.GETPROP:
      if (val.isQualifiedName()) {
        return defines.contains(val.getQualifiedName());
      }
  }
  return false;
}
 

/**
 * A "simple" operator is one whose children are expressions,
 * has no direct side-effects (unlike '+='), and has no
 * conditional aspects (unlike '||').
 */
static boolean isSimpleOperatorType(int type) {
  switch (type) {
    case Token.ADD:
    case Token.BITAND:
    case Token.BITNOT:
    case Token.BITOR:
    case Token.BITXOR:
    case Token.COMMA:
    case Token.DIV:
    case Token.EQ:
    case Token.GE:
    case Token.GETELEM:
    case Token.GETPROP:
    case Token.GT:
    case Token.INSTANCEOF:
    case Token.LE:
    case Token.LSH:
    case Token.LT:
    case Token.MOD:
    case Token.MUL:
    case Token.NE:
    case Token.NOT:
    case Token.RSH:
    case Token.SHEQ:
    case Token.SHNE:
    case Token.SUB:
    case Token.TYPEOF:
    case Token.VOID:
    case Token.POS:
    case Token.NEG:
    case Token.URSH:
      return true;

    default:
      return false;
  }
}
 

static int precedence(int type) {
  switch (type) {
    case Token.COMMA:  return 0;
    case Token.ASSIGN_BITOR:
    case Token.ASSIGN_BITXOR:
    case Token.ASSIGN_BITAND:
    case Token.ASSIGN_LSH:
    case Token.ASSIGN_RSH:
    case Token.ASSIGN_URSH:
    case Token.ASSIGN_ADD:
    case Token.ASSIGN_SUB:
    case Token.ASSIGN_MUL:
    case Token.ASSIGN_DIV:
    case Token.ASSIGN_MOD:
    case Token.ASSIGN: return 1;
    case Token.HOOK:   return 2;  // ?: operator
    case Token.OR:     return 3;
    case Token.AND:    return 4;
    case Token.BITOR:  return 5;
    case Token.BITXOR: return 6;
    case Token.BITAND: return 7;
    case Token.EQ:
    case Token.NE:
    case Token.SHEQ:
    case Token.SHNE:   return 8;
    case Token.LT:
    case Token.GT:
    case Token.LE:
    case Token.GE:
    case Token.INSTANCEOF:
    case Token.IN:     return 9;
    case Token.LSH:
    case Token.RSH:
    case Token.URSH:   return 10;
    case Token.SUB:
    case Token.ADD:    return 11;
    case Token.MUL:
    case Token.MOD:
    case Token.DIV:    return 12;
    case Token.INC:
    case Token.DEC:
    case Token.NEW:
    case Token.DELPROP:
    case Token.TYPEOF:
    case Token.VOID:
    case Token.NOT:
    case Token.BITNOT:
    case Token.POS:
    case Token.NEG:    return 13;

    case Token.ARRAYLIT:
    case Token.CALL:
    case Token.EMPTY:
    case Token.FALSE:
    case Token.FUNCTION:
    case Token.GETELEM:
    case Token.GETPROP:
    case Token.GET_REF:
    case Token.IF:
    case Token.LP:
    case Token.NAME:
    case Token.NULL:
    case Token.NUMBER:
    case Token.OBJECTLIT:
    case Token.REGEXP:
    case Token.RETURN:
    case Token.STRING:
    case Token.THIS:
    case Token.TRUE:
      return 15;

    default: throw new Error("Unknown precedence for " +
                             Node.tokenToName(type) +
                             " (type " + type + ")");
  }
}
 

/**
 * Converts an operator's token value (see {@link Token}) to a string
 * representation.
 *
 * @param operator the operator's token value to convert
 * @return the string representation or {@code null} if the token value is
 * not an operator
 */
static String opToStr(int operator) {
  switch (operator) {
    case Token.BITOR: return "|";
    case Token.OR: return "||";
    case Token.BITXOR: return "^";
    case Token.AND: return "&&";
    case Token.BITAND: return "&";
    case Token.SHEQ: return "===";
    case Token.EQ: return "==";
    case Token.NOT: return "!";
    case Token.NE: return "!=";
    case Token.SHNE: return "!==";
    case Token.LSH: return "<<";
    case Token.IN: return "in";
    case Token.LE: return "<=";
    case Token.LT: return "<";
    case Token.URSH: return ">>>";
    case Token.RSH: return ">>";
    case Token.GE: return ">=";
    case Token.GT: return ">";
    case Token.MUL: return "*";
    case Token.DIV: return "/";
    case Token.MOD: return "%";
    case Token.BITNOT: return "~";
    case Token.ADD: return "+";
    case Token.SUB: return "-";
    case Token.POS: return "+";
    case Token.NEG: return "-";
    case Token.ASSIGN: return "=";
    case Token.ASSIGN_BITOR: return "|=";
    case Token.ASSIGN_BITXOR: return "^=";
    case Token.ASSIGN_BITAND: return "&=";
    case Token.ASSIGN_LSH: return "<<=";
    case Token.ASSIGN_RSH: return ">>=";
    case Token.ASSIGN_URSH: return ">>>=";
    case Token.ASSIGN_ADD: return "+=";
    case Token.ASSIGN_SUB: return "-=";
    case Token.ASSIGN_MUL: return "*=";
    case Token.ASSIGN_DIV: return "/=";
    case Token.ASSIGN_MOD: return "%=";
    case Token.VOID: return "void";
    case Token.TYPEOF: return "typeof";
    case Token.INSTANCEOF: return "instanceof";
    default: return null;
  }
}
 

/**
 * Updates our respresentation of the global namespace to reflect a read
 * of a global name.
 *
 * @param t The traversal
 * @param n The node currently being visited
 * @param parent {@code n}'s parent
 * @param name The global name (e.g. "a" or "a.b.c.d")
 */
void handleGet(NodeTraversal t, Node n, Node parent, String name) {
  if (maybeHandlePrototypePrefix(t, n, parent, name)) return;

  Ref.Type type = Ref.Type.DIRECT_GET;
  if (parent != null) {
    switch (parent.getType()) {
      case Token.IF:
      case Token.TYPEOF:
      case Token.VOID:
      case Token.NOT:
      case Token.BITNOT:
      case Token.POS:
      case Token.NEG:
        break;
      case Token.CALL:
        type = n == parent.getFirstChild()
               ? Ref.Type.CALL_GET
               : Ref.Type.ALIASING_GET;
        break;
      case Token.NEW:
        type = n == parent.getFirstChild()
               ? Ref.Type.DIRECT_GET
               : Ref.Type.ALIASING_GET;
        break;
      case Token.OR:
      case Token.AND:
        // This node is x or y in (x||y) or (x&&y). We only know that an
        // alias is not getting created for this name if the result is used
        // in a boolean context or assigned to the same name
        // (e.g. var a = a || {}).
        type = determineGetTypeForHookOrBooleanExpr(t, parent, name);
        break;
      case Token.HOOK:
        if (n != parent.getFirstChild()) {
          // This node is y or z in (x?y:z). We only know that an alias is
          // not getting created for this name if the result is assigned to
          // the same name (e.g. var a = a ? a : {}).
          type = determineGetTypeForHookOrBooleanExpr(t, parent, name);
        }
        break;
      default:
        type = Ref.Type.ALIASING_GET;
        break;
    }
  }

  handleGet(t, n, parent, name, type);
}
 

/**
 * Determines whether the result of a hook (x?y:z) or boolean expression
 * (x||y) or (x&&y) is assigned to a specific global name.
 *
 * @param t The traversal
 * @param parent The parent of the current node in the traversal. This node
 *     should already be known to be a HOOK, AND, or OR node.
 * @param name A name that is already known to be global in the current
 *     scope (e.g. "a" or "a.b.c.d")
 * @return The expression's get type, either {@link Ref.Type#DIRECT_GET} or
 *     {@link Ref.Type#ALIASING_GET}
 */
Ref.Type determineGetTypeForHookOrBooleanExpr(
    NodeTraversal t, Node parent, String name) {
  Node prev = parent;
  for (Node anc : parent.getAncestors()) {
    switch (anc.getType()) {
      case Token.EXPR_RESULT:
      case Token.VAR:
      case Token.IF:
      case Token.WHILE:
      case Token.FOR:
      case Token.TYPEOF:
      case Token.VOID:
      case Token.NOT:
      case Token.BITNOT:
      case Token.POS:
      case Token.NEG:
        return Ref.Type.DIRECT_GET;
      case Token.HOOK:
        if (anc.getFirstChild() == prev) {
          return Ref.Type.DIRECT_GET;
        }
        break;
      case Token.ASSIGN:
        if (!name.equals(anc.getFirstChild().getQualifiedName())) {
          return Ref.Type.ALIASING_GET;
        }
        break;
      case Token.NAME:  // a variable declaration
        if (!name.equals(anc.getString())) {
          return Ref.Type.ALIASING_GET;
        }
        break;
      case Token.CALL:
        if (anc.getFirstChild() != prev) {
          return Ref.Type.ALIASING_GET;
        }
        break;
    }
    prev = anc;
  }
  return Ref.Type.ALIASING_GET;
}