'get the next character, excluding comments. peek() is used to see
if a \'/\' is followed by a \'/\' or \'*\'.'

def _next(self):

    c = self._get()
    if (c == '/'):
        p = self._peek()
        if (p == '/'):
            c = self._get()
            while (c > '\n'):
                c = self._get()
            return c
        if (p == '*'):
            c = self._get()
            while 1:
                c = self._get()
                if (c == '*'):
                    if (self._peek() == '/'):
                        self._get()
                        return '    '
                if (c == '\x00'):
                    raise UnterminatedComment()
    return c
