Expand ongoing process as an x schema - sjdayday/xschema GitHub Wiki
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So far, the Grasp x-schema is completely abstract. The main action of Grasp involves closing the hand around the target object. Suppose we have a previously built x-schema, Close_hand, which we will invoke as the ongoing process of Grasp. Grasp will be the parent Petri net, and Close_hand will be a child Petri net. This means linking a set of Grasp's components, the Ongoing state and its prior and successor transitions, Start and Finish, with the Close_hand x-schema:
Specifically, by convention we use the parent's Start transition to drive the marking both of the Ongoing state in the parent Petri net, and the Enabled state in the child Petri net (Close_hand). Also by convention we use the Done place in the child Petri net (Close_hand) as an input arc to the Finish transition in the parent Petri net (Grasp), such that marking the Done place in Close_hand, in combination with the existing marking in Ongoing in Grasp, will cause the Grasp Finish transition to fire.