def __init__(self, parent:CharacterStream):
CharacterStream.__init__(self, parent.name)
# The stream from which we obtain the (absolute) characters.
self._parent = parent
# Keeps the first StreamPosition_ of the various indentation levels
self._stack = [parent.copy_position()]
# Keeps the StreamPosition_ of the current character, relative to the position in the top of the stack
self.current_relative_position = StreamPosition(self.name, 0, 1, 1, 1)
# Remembers whether the substream has finished reading
self.relative_eof = False
