--- title: 'node_definition(7advtrains)' manual: 'Advtrains Developer''s Manual' seealso: - signal_aspects(7advtrains) --- # Name `node_definition` - Advtrains-specific node definition entries # Description This page describes various fields in node definition tables that are used by Advtrains. # Node Groups Advtrains uses node groups to identify certain properties of a node. The following node groups are currently read by Advtrains: * `advtrains_signal`: When set, this property defines the type of signal this node belongs to. `1` indicates that this node is a static signal, and `2` indicates that this node is a signal with a variable aspect. * `not_blocking_trains`: When set to 1, trains can move through this node. * `save_in_at_nodedb`: When set to 1, this node should be saved in the internal node database used by Advtrains. # The `advtrains` Field The `advtrains` field in the node definition may contain the following fields: * `get_aspect(pos, node)`: This function should return the signal aspect of the node at the given position. * `set_aspect(pos, node, asp)`: This function should set the signal aspect of the node to `asp` if possible. `asp` is not guranteed to be an aspect supported by the node. * `supported_aspects`: This table should contain a list of supported signal aspects.