/**
 * @dependency ABooleanExp uses
 */
public class TestEvalEnv
{
	/**
	 * @param args 
	 */
	public static void main(String[] args)
	{
      Environment env = new ConsEnv ("x", true, new ConsEnv ("y", false, EmptyEnv.Singleton ()));
      IBEVisitor eval = EvalVisitor.Singleton ();
      ABooleanExp e1 = new And (Constant.Singleton (true), new Variable ("x"));
      ABooleanExp e2 = new Or (Constant.Singleton (false), e1);
      ABooleanExp e3 = new Implies (e2, e1);
      ABooleanExp e4 = new Implies (e1, e2);
      System.out.println (e1 + " == " + e1.accept (eval, env));
      System.out.println (e2 + " == " + e2.accept (eval, env));
      System.out.println (e3 + " == " + e3.accept (eval, env));
      System.out.println (e4 + " == " + e4.accept (eval, env));

      /* test DeMorgan's law */
      Variable  x = new Variable("x");
      Variable  y = new Variable("y");
      ABooleanExp demorgan1 = new Implies(new Or(x, y),
					  new Not( new And(new Not(x),
							   new Not(y))));
      ABooleanExp demorgan2 = new Implies(new Not( new And(new Not(x),
							   new Not(y))),
					  new Or(x, y));
      Environment env1 = new ConsEnv("x", true,
				     new ConsEnv("y", true,
						 EmptyEnv.Singleton()));
      Environment env2 = new ConsEnv("x", true,
				     new ConsEnv("y", false,
						 EmptyEnv.Singleton()));
      Environment env3 = new ConsEnv("x", false,
				     new ConsEnv("y", true,
						 EmptyEnv.Singleton()));
      Environment env4 = new ConsEnv("x", false,
				     new ConsEnv("y", false,
						 EmptyEnv.Singleton()));
      System.out.println ("\nTesting DeMorgan's laws...");
      System.out.println (demorgan1 +"[" + env1 + "] == " + demorgan1.accept (eval, env1));
      System.out.println (demorgan1 +"[" + env2 + "] == " + demorgan1.accept (eval, env2));
      System.out.println (demorgan1 +"[" + env3 + "] == " + demorgan1.accept (eval, env3));
      System.out.println (demorgan1 +"[" + env4 + "] == " + demorgan1.accept (eval, env4));
      System.out.println (demorgan2 +"[" + env1 + "] == " + demorgan2.accept (eval, env1));
      System.out.println (demorgan2 +"[" + env2 + "] == " + demorgan2.accept (eval, env2));
      System.out.println (demorgan2 +"[" + env3 + "] == " + demorgan2.accept (eval, env3));
      System.out.println (demorgan2 +"[" + env4 + "] == " + demorgan2.accept (eval, env4));
	}
}