main.java

我开发的一个用java语言实现的编译器,内含词法分析器,语法分析器,而且可以实现中间代码生成.用到了SLR算法和LR(1)算法

	      /* record the name */
	      emit.package_name = argv[i];
	    }
	  else if (argv[i].equals("-parser"))
	    {
	      /* must have an arg */
	      if (++i >= len || argv[i].startsWith("-") || 
				argv[i].endsWith(".cup")) 
		usage("-parser must have a name argument");

	      /* record the name */
	      emit.parser_class_name = argv[i];
	    }
	  else if (argv[i].equals("-symbols"))
	    {
	      /* must have an arg */
	      if (++i >= len || argv[i].startsWith("-") || 
				argv[i].endsWith(".cup")) 
		usage("-symbols must have a name argument");

	      /* record the name */
	      emit.symbol_const_class_name = argv[i];
	    }
	  else if (argv[i].equals("-nonterms"))
	    {
	      include_non_terms = true;
	    }
	  else if (argv[i].equals("-expect"))
	    {
	      /* must have an arg */
	      if (++i >= len || argv[i].startsWith("-") || 
				argv[i].endsWith(".cup")) 
		usage("-expect must have a name argument");

	      /* record the number */
	      try {
	        expect_conflicts = Integer.parseInt(argv[i]);
	      } catch (NumberFormatException e) {
		usage("-expect must be followed by a decimal integer");
	      }
	    }
	  else if (argv[i].equals("-compact_red"))  opt_compact_red = true;
	  else if (argv[i].equals("-nosummary"))    no_summary = true;
	  else if (argv[i].equals("-nowarn"))       emit.nowarn = true;
	  else if (argv[i].equals("-dump_states"))  opt_dump_states = true;
	  else if (argv[i].equals("-dump_tables"))  opt_dump_tables = true; 
	  else if (argv[i].equals("-progress"))     print_progress = true;
	  else if (argv[i].equals("-dump_grammar")) opt_dump_grammar = true;
	  else if (argv[i].equals("-dump")) 
	        opt_dump_states = opt_dump_tables = opt_dump_grammar = true; 
	  else if (argv[i].equals("-time"))         opt_show_timing = true; 
	  else if (argv[i].equals("-debug"))        opt_do_debug = true;
	  /* frankf 6/18/96 */
	  else if (argv[i].equals("-nopositions"))  lr_values = false;
	  /* CSA 12/21/97 */
	  else if (argv[i].equals("-interface"))    sym_interface = true;
	  /* CSA 23-Jul-1999 */
	  else if (argv[i].equals("-noscanner"))    suppress_scanner = true;
	  /* CSA 23-Jul-1999 */
	  else if (argv[i].equals("-version")) {
	      System.out.println(version.title_str);
	      System.exit(1);
	  }
	  /* CSA 24-Jul-1999; suggestion by Jean Vaucher */
	  else if (!argv[i].startsWith("-") && i==len-1) {
	      /* use input from file. */
	      try {
		  System.setIn(new FileInputStream(argv[i]));
	      } catch (java.io.FileNotFoundException e) {
		  usage("Unable to open \"" + argv[i] +"\" for input");
	      }
	  }
	  else
	    {
	      usage("Unrecognized option \"" + argv[i] + "\"");
	    }
	}
    }

  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/

  /*-------*/
  /* Files */
  /*-------*/

  /** Input file.  This is a buffered version of System.in. */
  protected static BufferedInputStream input_file;

  /** Output file for the parser class. */
  protected static PrintWriter parser_class_file;

  /** Output file for the symbol constant class. */
  protected static PrintWriter symbol_class_file;

  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/

  /** Open various files used by the system. */
  protected static void open_files()
    {
      File fil;
      String out_name;

      /* open each of the output files */

      /* parser class */
      out_name = emit.parser_class_name + ".java";
      fil = new File(out_name);
      try {
        parser_class_file = new PrintWriter(
		 new BufferedOutputStream(new FileOutputStream(fil), 4096));
      } catch(Exception e) {
	System.err.println("Can't open \"" + out_name + "\" for output");
	System.exit(3);
      }

      /* symbol constants class */
      out_name = emit.symbol_const_class_name + ".java";
      fil = new File(out_name);
      try {
        symbol_class_file = new PrintWriter(
		 new BufferedOutputStream(new FileOutputStream(fil), 4096));
      } catch(Exception e) {
	System.err.println("Can't open \"" + out_name + "\" for output");
	System.exit(4);
      }
    }

  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/

  /** Close various files used by the system. */
  protected static void close_files() throws java.io.IOException
    {
      if (input_file != null) input_file.close();
      if (parser_class_file != null) parser_class_file.close();
      if (symbol_class_file != null) symbol_class_file.close();
    }

  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/

  /** Parse the grammar specification from standard input.  This produces
   *  sets of terminal, non-terminals, and productions which can be accessed
   *  via static variables of the respective classes, as well as the setting
   *  of various variables (mostly in the emit class) for small user supplied
   *  items such as the code to scan with.
   */
  protected static void parse_grammar_spec() throws java.lang.Exception
    {
      parser parser_obj;

      /* create a parser and parse with it */
      parser_obj = new parser();
      try {
	if (opt_do_debug)
          parser_obj.debug_parse();
	else
          parser_obj.parse();
      } catch (Exception e)
      {
	/* something threw an exception.  catch it and emit a message so we 
	   have a line number to work with, then re-throw it */
	lexer.emit_error("Internal error: Unexpected exception");
	throw e;
      }
    }

  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/

  /** Check for unused symbols.  Unreduced productions get checked when
   *  tables are created.
   */
  protected static void check_unused()
    {
      terminal term;
      non_terminal nt;

      /* check for unused terminals */
      for (Enumeration t = terminal.all(); t.hasMoreElements(); )
	{
	  term = (terminal)t.nextElement();

	  /* don't issue a message for EOF */
	  if (term == terminal.EOF) continue;

	  /* or error */
	  if (term == terminal.error) continue;

	  /* is this one unused */
	  if (term.use_count() == 0)
	    {
	      /* count it and warn if we are doing warnings */
	      emit.unused_term++;
	      if (!emit.nowarn) 
		{
		  System.err.println("Warning: Terminal \"" + term.name() + 
				     "\" was declared but never used");
		  lexer.warning_count++;
		}
	    }
	}

      /* check for unused non terminals */
      for (Enumeration n = non_terminal.all(); n.hasMoreElements(); )
	{
	  nt = (non_terminal)n.nextElement();

	  /* is this one unused */
	  if (nt.use_count() == 0)
	    {
	      /* count and warn if we are doing warnings */
	      emit.unused_term++;
	      if (!emit.nowarn) 
		{
		  System.err.println("Warning: Non terminal \"" + nt.name() + 
				     "\" was declared but never used");
		  lexer.warning_count++;
		}
	    }
	}

    }

  /* . . . . . . . . . . . . . . . . . . . . . . . . .*/
  /* . . Internal Results of Generating the Parser . .*/
  /* . . . . . . . . . . . . . . . . . . . . . . . . .*/

  /** Start state in the overall state machine. */
  protected static lalr_state start_state;

  /** Resulting parse action table. */
  protected static parse_action_table action_table;

  /** Resulting reduce-goto table. */
  protected static parse_reduce_table reduce_table;

  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/

  /** Build the (internal) parser from the previously parsed specification.
   *  This includes:<ul>
   *    <li> Computing nullability of non-terminals.
   *    <li> Computing first sets of non-terminals and productions.
   *    <li> Building the viable prefix recognizer machine.
   *    <li> Filling in the (internal) parse tables.
   *    <li> Checking for unreduced productions.
   *  </ul>
   */
  protected static void build_parser() throws internal_error
    {
      /* compute nullability of all non terminals */
      if (opt_do_debug || print_progress) 
	System.err.println("  Computing non-terminal nullability...");
      non_terminal.compute_nullability();

      nullability_end = System.currentTimeMillis();

      /* compute first sets of all non terminals */
      if (opt_do_debug || print_progress) 
	System.err.println("  Computing first sets...");
      non_terminal.compute_first_sets();

      first_end = System.currentTimeMillis();

      /* build the LR viable prefix recognition machine */
      if (opt_do_debug || print_progress) 
	System.err.println("  Building state machine...");
      start_state = lalr_state.build_machine(emit.start_production);

      machine_end = System.currentTimeMillis();

      /* build the LR parser action and reduce-goto tables */
      if (opt_do_debug || print_progress) 
	System.err.println("  Filling in tables...");
      action_table = new parse_action_table();
      reduce_table = new parse_reduce_table();
      for (Enumeration st = lalr_state.all(); st.hasMoreElements(); )
	{
	  lalr_state lst = (lalr_state)st.nextElement();
	  lst.build_table_entries(
			                      action_table, reduce_table);
	}

      table_end = System.currentTimeMillis();

      /* check and warn for non-reduced productions */
      if (opt_do_debug || print_progress)