def parse_students(course, year, no, exam):
    ret = []
    appellore = re.compile(_appelloptn)
    studentre = re.compile(_studentptn)
    url = "http://compass2.di.unipi.it/didattica/%s/share/orario/Appelli/" % course \
         + "appelliret.asp?letter=&ycourse=&course=%s&year=%d&start=%d&end=%d&chk=%s" % \
         (course, year, no, no, exam)
    h = utils.web.url2html(url)
    matches = appellore.finditer(h)
    try:
        m = matches.next()
    except StopIteration:
        return []
    url = "http://compass2.di.unipi.it/didattica/inf31/share/orario/Appelli/lista.asp?action=list&appello=%s" \
        % m.group(1)

    h = utils.web.url2html(url)
    matches = studentre.finditer(h)
    ok = True
    while ok:
        try:
            m = matches.next()
            ret.append([m.group(1), m.group(2), m.group(3), m.group(4)])
            #print m.group(1), m.group(2), m.group(3), "Note:", m.group(4)
        except StopIteration:
            ok = False

    return ret