/*
 * ListPlusPlus.java
 *
 * Created on March 29, 2007, 9:45 PM
 *
 * To change this template, choose Tools | Options and locate the template under
 * the Source Creation and Management node. Right-click the template and choose
 * Open. You can then make changes to the template in the Source Editor.
 */
/**
 *
 * @author Jeff
 */
public class ListPlusPlus extends List{
    
    /** Creates a new instance of ListPlusPlus */
    public ListPlusPlus() {
    }
    
    public static List stutter(List k) throws BadIndexException
    {
        if (ListPlus.isEmpty(k))
            return List.nil();
        else
        {
            Element a = k.getMember(0);
            List l = ListPlus.drop(1,k);
            return ListPlus.cons(a,ListPlus.cons(a, stutter(l)));
            
        }
    }
    
    public static List prefix(List k) throws BadIndexException
    {
        if (ListPlus.isEmpty(k))
            return List.nil();
        else
        {
            List l = List.nil();
            int i =1;
            while (i<ListPlus.getLength(k))
            {
                l= ListPlus.cons(ListPlus.take(i,k),l);
                i++;
            }
            return ListPlus.cons(l, prefix(ListPlus.drop(1,k)));
        }
    }
    
    public static List suffix(List k) throws BadIndexException
    {
        if (ListPlus.isEmpty(k))
            return List.nil();
        else
        {
            List l = List.nil();
            int i =ListPlus.getLength(k)-1;
            while (i>=1)
            {
                l= ListPlus.cons(ListPlus.drop(i,k),l);
                i--;
            }
            return ListPlus.cons(l,suffix(ListPlus.take(ListPlus.getLength(k)-1,k)));
        }
    }
    
}