code: //==============================================================================
  //	
  //	Copyright (c) 2002-
  //	Authors:
  //	* Dave Parker <david.parker@comlab.ox.ac.uk> (University of Oxford)
  //	
  //------------------------------------------------------------------------------
  //	
  //	This file is part of PRISM.
  //	
  //	PRISM is free software; you can redistribute it and/or modify
  //	it under the terms of the GNU General Public License as published by
  //	the Free Software Foundation; either version 2 of the License, or
  //	(at your option) any later version.
  //	
  //	PRISM is distributed in the hope that it will be useful,
  //	but WITHOUT ANY WARRANTY; without even the implied warranty of
  //	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  //	GNU General Public License for more details.
  //	
  //	You should have received a copy of the GNU General Public License
  //	along with PRISM; if not, write to the Free Software Foundation,
  //	Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  //	
  //==============================================================================
  
  package parser.visitor;
  
  import parser.ast.*;
  import prism.PrismLangException;
  
  /**
   * Compute (maximum) number of nested probabilistic operators (P, S, R).
   */
  public class ComputeProbNesting extends ASTTraverse
  {
  	private int currentNesting;
  	private int maxNesting;
  	
  	public ComputeProbNesting()
  	{
  		currentNesting = 0;
  		maxNesting = 0;
  	}
  
  	public int getMaxNesting()
  	{
  		return maxNesting;
  	}
  	
  	public void visitPre(ExpressionProb e) throws PrismLangException
  	{
  		currentNesting++;
  		maxNesting = Math.max(maxNesting, currentNesting);
  	}
  
  	public void visitPost(ExpressionProb e) throws PrismLangException
  	{
  		currentNesting--;
  	}
  
  	public void visitPre(ExpressionReward e) throws PrismLangException
  	{
  		currentNesting++;
  		maxNesting = Math.max(maxNesting, currentNesting);
  	}
  
  	public void visitPost(ExpressionReward e) throws PrismLangException
  	{
  		currentNesting--;
  	}
  
  	public void visitPre(ExpressionSS e) throws PrismLangException
  	{
  		currentNesting++;
  		maxNesting = Math.max(maxNesting, currentNesting);
  	}
  	
  	public void visitPost(ExpressionSS e) throws PrismLangException
  	{
  		currentNesting--;
  	}
  }
  
  