expr.cxx

eCos1.31版

        case T_Exclamation:     result = CdlExprOp_LogicalNot; break;
        case T_Tilde:           result = CdlExprOp_BitNot; break;
        case T_Questionmark:
        case T_Colon:           result = CdlExprOp_Cond; break; // best guess
            
        case T_OpenBracket:
        case T_CloseBracket:
        case T_Invalid:
        default:                result = CdlExprOp_Invalid; break;
        }
    }
    CYG_REPORT_RETVAL(result);
    return result;
}

// A utility routine to turn the current token back into a string
// This is used for diagnostics.
static std::string
token_to_string()
{
    CYG_REPORT_FUNCNAME("token_to_string");
    std::string result = "";

    switch(current_token) {
      case T_EOD:               result = "<end of data>"; break;
      case T_Reference:         result = "reference to " + current_reference; break;
      case T_String:            result = "string \"" + current_string + "\""; break;
      case T_Integer:
      {
          std::string tmp;
          Cdl::integer_to_string(current_int, tmp, current_format);
          result = "integer constant " + tmp;
          break;
      }
      case T_Double:
      {
          std::string tmp;
          Cdl::double_to_string(current_double, tmp, current_format);
          result = "double constant " + tmp;
          break;
      }
      case T_Range:             result = "range operator \"to\""; break;
      case T_OpenBracket:       result = "open bracket ("; break;
      case T_CloseBracket:      result = "close bracket )"; break;
      case T_Minus:             result = "minus sign -"; break;
      case T_Plus:              result = "plus sign +"; break;
      case T_Times:             result = "multiply operator *"; break;
      case T_Divide:            result = "divide operator /"; break;
      case T_Exclamation:       result = "not operator !"; break;
      case T_Tilde:             result = "bitwise not operator ~"; break;
      case T_Questionmark:      result = "question mark ?"; break;
      case T_Remainder:         result = "remainder operator %"; break;
      case T_LeftShift:         result = "left shift operator <<"; break;
      case T_RightShift:        result = "right shift operator >>"; break;
      case T_LessThan:          result = "less-than operator <"; break;
      case T_LessEqual:         result = "less-or-equal operator <="; break;
      case T_GreaterThan:       result = "greater-than operator >"; break;
      case T_GreaterEqual:      result = "greater-or-equal operator >="; break;
      case T_Equal:             result = "equality operator =="; break;
      case T_NotEqual:          result = "not-equal operator !="; break;
      case T_BitAnd:            result = "bitwise and operator &"; break;
      case T_BitXor:            result = "bitwise xor operator ^"; break;
      case T_BitOr:             result = "bitwise or operator |"; break;
      case T_And:               result = "and operator &&"; break;
      case T_Or:                result = "or operator ||"; break;
      case T_Colon:             result = "colon"; break;
      case T_Invalid:
      default:                  result = "<invalid token>"; break;
    }

    CYG_REPORT_RETURN();
    return result;
}

//}}}
//{{{  Literals                         

// ----------------------------------------------------------------------------
//{{{  process_string()                 

// The start of a string has been detected. Work out the entire string,
// allowing for backslash escapes.
static void
process_string()
    throw(CdlParseException, std::bad_alloc)
{
    CYG_REPORT_FUNCNAME("process_string");
    CYG_ASSERTC('"' == current_char);
    CYG_ASSERTC("" == current_string);

    std::string result = "";

    // Move past the leading quote mark.
    next_char();
    while ('"' != current_char) {
        if (EOF == current_char) {
            throw CdlParseException("Premature end of data in string constant.\n" + get_error_location());
        } else if ('\\' == current_char) {
            // Allow \a, \b, \f, \n, \r, \t, \v, \ddd and \xhh.
            // Also copy with \newline space.
            // Any other character gets passed through unchanged.
            next_char();
            switch(current_char) {
              case EOF:
                throw CdlParseException("Premature end of data after backslash in string constant.\n" + get_error_location());
              case 'a':
                result += '\a';
                break;
              case 'b':
                result += '\b';
                break;
              case 'f':
                result += '\f';
                break;
              case 'n':
                result += '\n';
                break;
              case 'r':
                result += '\r';
                break;
              case 't':
                result += '\t';
                break;
              case 'v':
                result += '\v';
                break;
              case 'x':
              {
                cdl_int tmp = 0;
                next_char();
                if (!isxdigit(current_char)) {
                    throw CdlParseException("Non-hexadecimal digit detected in string \\x escape sequence.\n" +
                        get_error_location());
                }
                // NOTE: there is no overflow detection here.
                do {
                    tmp *= 16;
                    if (('0' <= current_char) && (current_char <= '9')) {
                        tmp += (current_char - '0');
                    } else if (('a' <= current_char) && (current_char <= 'f')) {
                        tmp += 10 + (current_char - 'a');
                    } else if (('A' <= current_char) && (current_char <= 'F')) {
                        tmp += 10 + (current_char - 'A');
                    } else {
                        CYG_FAIL("C library error, isxdigit() succeeded on non-hexadecimal character");
                    }
                    next_char();
                } while(isxdigit(current_char));
                backup_char();
                result += (char) tmp;
              }

              case '\n':
                next_char();
                while ((EOF != current_char) && isspace(current_char)) {
                    next_char();
                }
                // We have gone one too far, back up.
                backup_char();
                result += " ";
                break;

              default:
                if (('0' <= current_char) && (current_char <= '7')) {
                    // A sequence of octal digits.
                    cdl_int tmp = 0;
                    do {
                        tmp = (8 * tmp) + (current_char - '0');
                        next_char();
                    } while (('0' <= current_char) && (current_char <= '7'));
                    backup_char();
                    result += (char) tmp;
                } else {
                    // For all other backslash sequences, just add the second character
                    result += (char) current_char;
                }
            }
        } else {
            result += (char) current_char;
        }
        next_char();
    }
    // The closing quote has been reached, move past it.
    next_char();

    // And all done.
    current_token  = T_String;
    current_string = result;

    CYG_REPORT_RETURN();
}

//}}}
//{{{  process_number()                 

// The start of a number has been detected. This number may be an
// integer or a double. It is necessary to figure out where the number
// ends and invoke the appropriate Cdl:: conversion utility.
//
// Care has to be taken with termination. Consider a token such as
// 134_5. This is not a string because there are no quote marks, nor
// is it a valid reference, and because it begins with a digit it
// should be interpreted as a number. The 134 bit works fine, then
// number processing stops leaving current_char as '_'. If we are
// parsing a list expression then the following _5 will actually
// be interpreted as a reference. To avoid this, here is a utility
// which checks number completion and throws an exception if
// necessary.
static void check_number_termination()
    throw(CdlParseException, std::bad_alloc)
{
    CYG_REPORT_FUNCNAME("check_number_termination");

    // End-of-data or any whitespace is ok.
    if ((EOF != current_char) && !isspace(current_char)) {
        // Any valid operator is ok as well, or brackets for that matter.
        if (('-' != current_char) && ('+' != current_char) && ('*' != current_char) &&
            ('/' != current_char) && ('!' != current_char) && ('~' != current_char) &&
            ('?' != current_char) && ('%' != current_char) && ('<' != current_char) &&
            ('>' != current_char) && ('=' != current_char) && ('&' != current_char) &&
            ('^' != current_char) && ('|' != current_char) && (':' != current_char) &&
            ('(' != current_char) && (')' != current_char)) {

            std::string tmp;
            Cdl::integer_to_string(current_int, tmp);
            throw CdlParseException("Invalid character detected after number " + tmp + "\n" + get_error_location());
        }
    }
    
    CYG_REPORT_RETURN();
}

static void
process_number()
    throw(CdlParseException, std::bad_alloc)
{
    CYG_REPORT_FUNCNAME("process_number");

    std::string tmp      = "";
    bool        is_float = false;

    // Detect the special cases of 0x and octal numbers.
    if ('0' == current_char) {
        next_char();
        if (('x' == current_char) || ('X' == current_char)) {
            
            next_char();
            if (!isxdigit(current_char)) {
                throw CdlParseException("Invalid hexadecimal number, expected at least one hexadecimal digit after 0x.\n"
                                        + get_error_location());
            }
            current_int = 0;
            do {
                current_int *= 16;
                if (('0' <= current_char) && (current_char <= '9')) {
                    current_int += (current_char - '0');
                } else if (('a' <= current_char) && (current_char <= 'f')) {
                    current_int += 10 + (current_char - 'a');
                } else {
                    current_int += 10 + (current_char - 'A');
                }
                next_char();
            } while(isxdigit(current_char));
            current_token  = T_Integer;
            current_format = CdlValueFormat_Hex;
            check_number_termination();
            CYG_REPORT_RETURN();
            return;
                
        } else if (('0' <= current_char) && (current_char <= '7')) {

            current_int = 0;
            do {
                current_int *= 8;
                current_int += (current_char - '0');
                next_char();
            } while (('0' <= current_char) && (current_char <= '7'));
            current_token  = T_Integer;
            current_format = CdlValueFormat_Octal;
            check_number_termination();
            CYG_REPORT_RETURN();
            return;
            
        } else if (('8' == current_char) || ('9' == current_char)) {
            throw CdlParseException("08... and 09... are not valid  octal numbers.\n" + get_error_location());
        } else {
            // This could be plain 0, or 0.123
            // Backup, and let the rest of the code take care of things
            backup_char();
        }
    }
    
    do {
        tmp += (char) current_char;
        next_char();
    } while(isdigit(current_char));

    // If we have found a . then we have a floating point number with a fraction.
    if ('.' == current_char) {
        tmp += '.';
        next_char();
        if (!isdigit(current_char)) {
            throw CdlParseException("Invalid floating point constant, expected a digit for the fractional part.\n" +
                                    get_error_location());
        }
        is_float = true;
        do {
            tmp += (char) current_char;
            next_char();
        } while(isdigit(current_char));
    }

    // If we have found e or E then we have a floating point number with an exponent
    if (('e' == current_char) || ('E' == current_char)) {
        tmp += 'E';
        next_char();
        if (('+' == current_char) || ('-' == current_char)) {
            tmp += current_char;
            next_char();
        }
        if (!isdigit(current_char)) {
            throw CdlParseException("Invalid floating point constant, expected a digit for the exponent.\n" +
                                    get_error_location());
        }
        is_float = true;
        do {
            tmp += (char) current_char;
            next_char();
        } while(isdigit(current_char));
    }

    if (is_float) {
        if (!Cdl::string_to_double(tmp, current_double)) {
            throw CdlParseException("Invalid floating point constant `" + tmp + "'.\n" + get_error_location());
        } else {
            current_token = T_Double;
        }
    } else {
        if (!Cdl::string_to_integer(tmp, current_int)) {
            throw CdlParseException("Invalid integer constant `" + tmp + "'.\n" + get_error_location());
        } else {
            current_token = T_Integer;
        }
    }
    
    check_number_termination();
    CYG_REPORT_RETURN();
}

//}}}
//{{{  process_reference()              

// The start of a reference has been detected.
// A reference name must be a valid C preprocessor name, so the
// only characters allowed are underscore, upper and lower case
// characters, and digits. The first character cannot be a digit,
// but that has been checked already.
//
// Some care has to be taken with locale's, the C library may decide
// that a character is a letter even though the same character is not
// valid as far as the preprocessor is concerned.
static void
process_reference()
    throw(CdlParseException, std::bad_alloc)
{
    CYG_REPORT_FUNCNAME("process_reference");

    do {
       current_reference += (char) current_char;
       next_char();
    } while (('_' == current_char) || isdigit(current_char) ||
             (('a' <= current_char) && (current_char <= 'z')) ||
             (('A' <= current_char) && (current_char <= 'Z')));

    current_token = T_Reference;

    CYG_REPORT_RETURN();