def __init__(self,ring,polystr="",list=None):
'''Ideal constructor.
'''
self.ring = ring;
if list == None:
sr = StringReader( polystr );
tok = GenPolynomialTokenizer(ring.pset.ring,sr);
self.list = tok.nextPolynomialList();
else:
self.list = pylist2arraylist(list);
self.pset = OrderedPolynomialList(ring.ring,self.list);
