Thus far all attributes on bools (nodes) are boolean valued. The default un-attributed node assumes default values for all known attributes. Boolean attributes are contagious in that once they are set to non-default values, they cannot be unset. Non-default values also propagate bottom-up through ports in the instance hierarchy. (They cannot propagate top-down, for that would violate modularity.) Furthermore, when connecting nodes, the non-default value always dominates (spreads contagiously). Keep this in mind when deciding at which level of hierarchy to attach attributes.
Declares that the said node is a supply node. Supply nodes are treated specially in different back-end tools. t=0 indicates that supply is GND-like (low). t=1 indicates that supply is Vdd-like (high).
Declares that the said node is a reset node with initial value init. Reset nodes are treated specially in different back-end tools. init=0 indicates that supply is active-low. init=1 indicates that supply is active-high.
Nodes are initially iscomb=false. If b is true, node is marked as being driven combinationally, regardless of the actual fanin rule of the node. This can be used to tell other tools to not expect a staticizer on this node. If attribute value is unspecified, default value is true.
Nodes are initially iscomb=true. If b is false, direct other back-end tools to not automatically staticize this node for simulation or netlist generation purposes. If unspecified, default value is true.
Nodes are initially isrvc1=false, isrvc2=false, isrvc3=false. If b is true, label this node in a way meaningful for redundant keeper circuits. If unspecified, argument is implicitly true. Exclusivity between these attributes is not yet checked.
Diagnostic attributes.