main.java

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      {
	/* 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) 
	System.err.println("  Checking for non-reduced productions...");
      action_table.check_reductions();

      reduce_check_end = System.currentTimeMillis();

      /* if we have more conflicts than we expected issue a message and die */
      if (emit.num_conflicts > expect_conflicts)
	{
	  System.err.println("*** More conflicts encountered than expected " +
			     "-- parser generation aborted");
	  lexer.error_count++; // indicate the problem.
	  // we'll die on return, after clean up.
	}
    }

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

  /** Call the emit routines necessary to write out the generated parser. */
  protected static void emit_parser() throws internal_error
    {
      emit.symbols(symbol_class_file, include_non_terms, sym_interface);
      emit.parser(parser_class_file, action_table, reduce_table, 
		  start_state.index(), emit.start_production, opt_compact_red);
    }

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

  /** Helper routine to optionally return a plural or non-plural ending. 
   * @param val the numerical value determining plurality.
   */
  protected static String plural(int val)
    {
      if (val == 1)
	return "";
      else
	return "s";
    }

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

  /** Emit a long summary message to standard error (System.err) which 
   *  summarizes what was found in the specification, how many states were
   *  produced, how many conflicts were found, etc.  A detailed timing 
   *  summary is also produced if it was requested by the user.
   * @param output_produced did the system get far enough to generate code.
   */
  protected static void emit_summary(boolean output_produced)
    {
      final_time = System.currentTimeMillis();

      if (no_summary) return;

      System.err.println("------- " + version.title_str + 
			 " Parser Generation Summary -------");

      /* error and warning count */
      System.err.println("  " + lexer.error_count + " error" + 
	 plural(lexer.error_count) + " and " + lexer.warning_count + 
	 " warning" + plural(lexer.warning_count));

      /* basic stats */
      System.err.print("  " + terminal.number() + " terminal" + 
			 plural(terminal.number()) + ", ");
      System.err.print(non_terminal.number() + " non-terminal" + 
			 plural(non_terminal.number()) + ", and ");
      System.err.println(production.number() + " production" + 
			 plural(production.number()) + " declared, ");
      System.err.println("  producing " + lalr_state.number() + 
			 " unique parse states.");

      /* unused symbols */
      System.err.println("  " + emit.unused_term + " terminal" + 
			 plural(emit.unused_term) + " declared but not used.");
      System.err.println("  " + emit.unused_non_term + " non-terminal" + 
			 plural(emit.unused_term) + " declared but not used.");

      /* productions that didn't reduce */
      System.err.println("  " + emit.not_reduced + " production" + 
			 plural(emit.not_reduced) + " never reduced.");

      /* conflicts */
      System.err.println("  " + emit.num_conflicts + " conflict" +
			 plural(emit.num_conflicts) + " detected" +
	                 " (" + expect_conflicts + " expected).");

      /* code location */
      if (output_produced)
	System.err.println("  Code written to \"" + emit.parser_class_name + 
	        ".java\", and \"" + emit.symbol_const_class_name + ".java\".");
      else
	System.err.println("  No code produced.");

      if (opt_show_timing) show_times();

      System.err.println(
	"---------------------------------------------------- (" + 
	 version.version_str + ")");
    }

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

  /** Produce the optional timing summary as part of an overall summary. */
  protected static void show_times()
    {
      long total_time = final_time - start_time;

      System.err.println(". . . . . . . . . . . . . . . . . . . . . . . . . ");
      System.err.println("  Timing Summary");
      System.err.println("    Total time       "
        + timestr(final_time-start_time, total_time));
      System.err.println("      Startup        "
	+ timestr(prelim_end-start_time, total_time));
      System.err.println("      Parse          "
	+ timestr(parse_end-prelim_end, total_time) );
      if (check_end != 0)
        System.err.println("      Checking       "
	    + timestr(check_end-parse_end, total_time));
      if (check_end != 0 && build_end != 0)
        System.err.println("      Parser Build   "
	    + timestr(build_end-check_end, total_time));
      if (nullability_end != 0 && check_end != 0)
        System.err.println("        Nullability  "
	    + timestr(nullability_end-check_end, total_time));
      if (first_end != 0 && nullability_end != 0)
        System.err.println("        First sets   "
            + timestr(first_end-nullability_end, total_time));
      if (machine_end != 0 && first_end != 0)
        System.err.println("        State build  " 
	    + timestr(machine_end-first_end, total_time)); 
      if (table_end != 0 && machine_end != 0)
        System.err.println("        Table build  " 
	    + timestr(table_end-machine_end, total_time)); 
      if (reduce_check_end != 0 && table_end != 0)
        System.err.println("        Checking     " 
	    + timestr(reduce_check_end-table_end, total_time));
      if (emit_end != 0 && build_end != 0)
        System.err.println("      Code Output    "
	    + timestr(emit_end-build_end, total_time));
      if (emit.symbols_time != 0)
	System.err.println("        Symbols      "
	    + timestr(emit.symbols_time, total_time));
      if (emit.parser_time != 0)
	System.err.println("        Parser class "
	    + timestr(emit.parser_time, total_time));
      if (emit.action_code_time != 0)
	System.err.println("          Actions    "
	    + timestr(emit.action_code_time, total_time));
      if (emit.production_table_time != 0)
	System.err.println("          Prod table "
	    + timestr(emit.production_table_time, total_time));
      if (emit.action_table_time != 0)
	System.err.println("          Action tab "
	    + timestr(emit.action_table_time, total_time));
      if (emit.goto_table_time != 0)
	System.err.println("          Reduce tab "
	    + timestr(emit.goto_table_time, total_time));

      System.err.println("      Dump Output    "
	+ timestr(dump_end-emit_end, total_time));
    }

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

  /** Helper routine to format a decimal based display of seconds and
   *  percentage of total time given counts of milliseconds.   Note: this
   *  is broken for use with some instances of negative time (since we don't 
   *  use any negative time here, we let if be for now).
   * @param time_val   the value being formatted (in ms).
   * @param total_time total time percentages are calculated against (in ms).
   */
  protected static String timestr(long time_val, long total_time)
    {
      boolean neg;
      long    ms = 0;
      long    sec = 0;
      long    percent10;
      String  pad;

      /* work with positives only */
      neg = time_val < 0;
      if (neg) time_val = -time_val;

      /* pull out seconds and ms */
      ms = time_val % 1000;
      sec = time_val / 1000;

      /* construct a pad to blank fill seconds out to 4 places */
      if (sec < 10)   
	pad = "   ";
      else if (sec < 100)  
	pad = "  ";
      else if (sec < 1000) 
	pad = " ";
      else
	pad = "";

      /* calculate 10 times the percentage of total */
      percent10 = (time_val*1000)/total_time;

      /* build and return the output string */
      return (neg ? "-" : "") + pad + sec + "." + 
	     ((ms%1000)/100) + ((ms%100)/10) + (ms%10) + "sec" +
	     " (" + percent10/10 + "." + percent10%10 + "%)";
    }

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

  /** Produce a human readable dump of the grammar. */
  public static void dump_grammar() throws internal_error
    {
      int cnt;
      Enumeration t, n, p;
      production prod;

      System.err.println("===== Terminals =====");
      for (t = terminal.all(), cnt=0; t.hasMoreElements(); cnt++)
	{
	  System.err.print(((terminal)t.nextElement()).name() + " ");
	  if ((cnt+1) % 5 == 0) System.err.println();
	}
      System.err.println();
      System.err.println();

      System.err.println("===== Non terminals =====");
      for (n=non_terminal.all(), cnt=0; n.hasMoreElements(); cnt++)
	{
	  System.err.print(((non_terminal)n.nextElement()).name() + " ");
	  if ((cnt+1) % 5 == 0) System.err.println();
	}
      System.err.println();
      System.err.println();


      System.err.println("===== Productions =====");
      for (p=production.all(); p.hasMoreElements(); )
	{
	  prod = (production)p.nextElement();
	  System.err.print(prod.lhs().the_symbol().name() + " ::= ");
	  for (int i=0; i<prod.rhs_length(); i++)
	    if (prod.rhs(i).is_action())
	      System.err.print("{action} ");
	    else
	      System.err.print(
			 ((symbol_part)prod.rhs(i)).the_symbol().name() + " ");
	  System.err.println();
	}
      System.err.println();
    }

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

  /** Produce a (semi-) human readable dump of the complete viable prefix 
   *  recognition state machine. 
   */
  public static void dump_machine()
    {
      lalr_state ordered[] = new lalr_state[lalr_state.number()];

      /* put the states in sorted order for a nicer display */
      for (Enumeration s = lalr_state.all(); s.hasMoreElements(); )
	{
	  lalr_state st = (lalr_state)s.nextElement();
	  ordered[st.index()] = st;
	}

      System.err.println("===== Viable Prefix Recognizer =====");
      for (int i = 0; i<lalr_state.number(); i++)
	{
	  if (ordered[i] == start_state) System.err.print("START ");
          System.err.println(ordered[i]);
	  System.err.println("-------------------");
	}
    }

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

  /** Produce a (semi-) human readable dumps of the parse tables */
  public static void dump_tables()
    {
      System.err.println(action_table);
      System.err.println(reduce_table);
    }

  /*-----------------------------------------------------------*/

}