Пример #1
0
  /**
   * Compile or interpret a Pascal source program.
   *
   * @param operation either "compile" or "execute".
   * @param filePath the source file path.
   * @param flags the command line flags.
   */
  public Pascal(String operation, String sourcePath, String inputPath, String flags) {
    try {
      intermediate = flags.indexOf('i') > -1;
      xref = flags.indexOf('x') > -1;

      source = new Source(new BufferedReader(new FileReader(sourcePath)));
      source.addMessageListener(new SourceMessageListener());

      parser = FrontendFactory.createParser("Pascal", "top-down", source);
      parser.addMessageListener(new ParserMessageListener());

      backend = BackendFactory.createBackend(operation, inputPath);
      backend.addMessageListener(new BackendMessageListener());

      parser.parse();
      source.close();

      if (parser.getErrorCount() == 0) {
        symTabStack = parser.getSymTabStack();

        SymTabEntry programId = symTabStack.getProgramId();
        iCode = (ICode) programId.getAttribute(ROUTINE_ICODE);

        if (xref) {
          CrossReferencer crossReferencer = new CrossReferencer();
          crossReferencer.print(symTabStack);
        }

        if (intermediate) {
          ParseTreePrinter treePrinter = new ParseTreePrinter(System.out);
          treePrinter.print(symTabStack);
        }
        backend.process(iCode, symTabStack);
      }
    } catch (Exception ex) {
      System.out.println("***** Internal translator error. *****");
      ex.printStackTrace();
    }
  }
Пример #2
0
  private ICodeNode parseIdentifier(Token token) throws Exception {
    ICodeNode rootNode = null;

    // Look up the identifier in the symbol table stack.
    // Flag the identifier as undefined if it's not found.
    String name = token.getText().toLowerCase();
    SymTabEntry id = symTabStack.lookup(name);

    // Undefined.
    if (id == null) {
      errorHandler.flag(token, IDENTIFIER_UNDEFINED, this);
      id = symTabStack.enterLocal(name);
      id.setDefinition(UNDEFINED);
      id.setTypeSpec(Predefined.undefinedType);
    }

    Definition defnCode = id.getDefinition();
    switch ((DefinitionImpl) defnCode) {
      case CONSTANT:
        {
          Object value = id.getAttribute(CONSTANT_VALUE);
          TypeSpec type = id.getTypeSpec();

          if (value instanceof Integer) {
            rootNode = ICodeFactory.createICodeNode(INTEGER_CONSTANT);
            rootNode.setAttribute(VALUE, value);
          } else if (value instanceof Float) {
            rootNode = ICodeFactory.createICodeNode(REAL_CONSTANT);
            rootNode.setAttribute(VALUE, value);
          } else if (value instanceof String) {
            rootNode = ICodeFactory.createICodeNode(STRING_CONSTANT);
            rootNode.setAttribute(VALUE, value);
          }

          id.appendLineNumber(token.getLineNumber());
          token = nextToken(); // consume the constant identifier

          if (rootNode != null) {
            rootNode.setTypeSpec(type);
          }

          break;
        }

      case ENUMERATION_CONSTANT:
        {
          Object value = id.getAttribute(CONSTANT_VALUE);
          TypeSpec type = id.getTypeSpec();

          rootNode = ICodeFactory.createICodeNode(INTEGER_CONSTANT);
          rootNode.setAttribute(VALUE, value);

          id.appendLineNumber(token.getLineNumber());
          token = nextToken(); // consume the enum constant identifier

          rootNode.setTypeSpec(type);
          break;
        }

      case FUNCTION:
        {
          CallParser callParser = new CallParser(this);
          rootNode = callParser.parse(token);
          break;
        }
      default:
        {
          VariableParser variableParser = new VariableParser(this);
          rootNode = variableParser.parse(token, id);
          break;
        }
    }
    return rootNode;
  }