Refactor 'port' demo to include starting point for assignment

examples/semantics/operational/port/helpers.py

@@ -0,0 +1,18 @@
+# Some helper functions
+
+def get_num_ships(od, place):
+    place_state = design_to_state(od, place)
+    return od.get_slot_value(place_state, "numShips")
+
+def design_to_state(od, design):
+    incoming = od.get_incoming(design, "of")
+    if len(incoming) == 1:
+        # not all design-objects have a state
+        return od.get_source(incoming[0])
+
+def state_to_design(od, state):
+    return od.get_target(od.get_outgoing(state, "of")[0])
+    
+def get_time(od):
+    _, clock = od.get_all_instances("Clock")[0]
+    return clock, od.get_slot_value(clock, "time")