/**
 * Negation.
 *
 * @version 1.1   September 27, 2001
 * @author Franck van Breugel
 * @see Expression
 */
public class Not extends Expression
{
    private Expression exp;

    /**
     * Negation.
     *
     * @param exp expression.
     */
    public Not(Expression exp)
    {
       this.exp = exp;
    }

    /**
     * Return a string representation.
     */
    public String toString()
    {
	return "not " + exp.toString();
    }

    /**
     * Accessor method for exp.
     */
    public Expression getExp()
    {
      return exp;
    }
}