"""each node descends from this base class""" class NodeType: def __init__(self): """TBD""" self.ops = Ops() ''' maybe self.iports = [] self.oports = [] self.params = [] ''' def get_state(self, stateaccess): """This is similar to the pickle.__getstate__ method, except we need this alternate version in order to give the node (which holds no state) access to its instance's state. If your node keeps some transient items in its state dict (such as a buffer of recently received inputs), it may want to return a copy of the state dict without those items. set_state should restore them properly (if they're missing from the current state, which they might not be). get_state might be called at any time, and it's certainly not guaranteed that the node instance is going out of service. get_state might get called to checkpoint the nodes for a backup, for example. set_state might also get called anytime. """ return stateaccess def set_state(self, stateaccess, dict): """dict (named after the pickle.__setstate__ argument) is always a value that was previously returned from get_state. Don't adjust the current nodetype's state, of course; use dict to update stateaccess. If there were elements missing from dict (see the note in get_state for why this might be the case), you should restore them here as appropriate. """ stateaccess.update(dict) def get_default_params(self): '''Returns dictionary of param names and DataType instances. DataTypes can be given values''' return {} def get_default_ports(self): '''Returns pinless port objects''' return {}