public void build_table_entries()

in util/src/main/java/java_cup/lalr_state.java [466:575]

• 80 lines of code
• 16 McCabe index (conditional complexity)

  public void build_table_entries(
    parse_action_table act_table, 
    parse_reduce_table reduce_table)
    throws internal_error
    {
      parse_action_row our_act_row;
      parse_reduce_row our_red_row;
      lalr_item        itm;
      parse_action     act, other_act;
      symbol           sym;
      terminal_set     conflict_set = new terminal_set();

      /* pull out our rows from the tables */
      our_act_row = act_table.under_state[index()];
      our_red_row = reduce_table.under_state[index()];

      /* consider each item in our state */
      for (Enumeration i = items().all(); i.hasMoreElements(); )
	{
	  itm = (lalr_item)i.nextElement();
	 

	  /* if its completed (dot at end) then reduce under the lookahead */
	  if (itm.dot_at_end())
	    {
	      act = new reduce_action(itm.the_production());

	      /* consider each lookahead symbol */
	      for (int t = 0; t < terminal.number(); t++)
		{
		  /* skip over the ones not in the lookahead */
		  if (!itm.lookahead().contains(t)) continue;

	          /* if we don't already have an action put this one in */
	          if (our_act_row.under_term[t].kind() == 
		      parse_action.ERROR)
		    {
	              our_act_row.under_term[t] = act;
		    }
	          else
		    {
		      /* we now have at least one conflict */
		      terminal term = terminal.find(t);
		      other_act = our_act_row.under_term[t];

		      /* if the other act was not a shift */
		      if ((other_act.kind() != parse_action.SHIFT) && 
			  (other_act.kind() != parse_action.NONASSOC))
		        {
		        /* if we have lower index hence priority, replace it*/
		          if (itm.the_production().index() < 
			      ((reduce_action)other_act).reduce_with().index())
			    {
			      /* replace the action */
			      our_act_row.under_term[t] = act;
			    }
		        } else {
			  /*  Check precedences,see if problem is correctable */
			  if(fix_with_precedence(itm.the_production(), 
						 t, our_act_row, act)) {
			    term = null;
			  }
			}
		      if(term!=null) {

			conflict_set.add(term);
		      }
		    }
		}
	    }
	}

      /* consider each outgoing transition */
      for (lalr_transition trans=transitions(); trans!=null; trans=trans.next())
	{
	  /* if its on an terminal add a shift entry */
	  sym = trans.on_symbol();
	  if (!sym.is_non_term())
	    {
	      act = new shift_action(trans.to_state());

	      /* if we don't already have an action put this one in */
	      if ( our_act_row.under_term[sym.index()].kind() == 
		   parse_action.ERROR)
		{
	          our_act_row.under_term[sym.index()] = act;
		}
	      else
		{
		  /* we now have at least one conflict */
		  production p = ((reduce_action)our_act_row.under_term[sym.index()]).reduce_with();

		  /* shift always wins */
		  if (!fix_with_precedence(p, sym.index(), our_act_row, act)) {
		    our_act_row.under_term[sym.index()] = act;
		    conflict_set.add(terminal.find(sym.index()));
		  }
		}
	    }
	  else
	    {
	      /* for non terminals add an entry to the reduce-goto table */
	      our_red_row.under_non_term[sym.index()] = trans.to_state();
	    }
	}

      /* if we end up with conflict(s), report them */
      if (!conflict_set.empty())
        report_conflicts(conflict_set);
    }