rev

#!/usr/bin/env python


class Elem(object):
    def __init__(self, value, next=None):
        self.value = value
        self.next = next

    def __str___(self):
        return self.value.__str__()
    def __repr__(self):
        return self.value.__repr__()



class SList(object):
    def __init__(self, l=None):
        self.root = Elem(None)
        if l is not None:
            for elem in l:
                self.add(elem)


    def add(self, value):
        cur = self.root
        while cur.next is not None:
            cur = cur.next
        cur.next = Elem(value)


    def __str__(self):
        return self.__repr__()

    def __repr__(self):
        cur = self.root
        s = ""
        while True:
            cur = cur.next
            if cur is None:
                break
            s = str(cur).join((s, ", "))

        return ''.join(("List: [", s[:-2], "]"))


    def rev(self):
        cur = self.root.next
        left = None
        while True:
            if cur is None:
                break
            right = cur.next
            cur.next = left
            left = cur
            cur = right

        self.root.next = left


l = SList((0, 1,2,3,4,5))
print l

l.rev()

print l