Motivation:
Want to enable/disable Supply depots based on the contents of the road network.
e.g. To set priorities so that one "Supply Depot" is exhausted before other "Supply Depots" are used.
See 1 and 2 for discussion about this elsewhere.
Challenge:
The mod gives you the "Road network reader", which reads the content of all currently enabled "Supply Depots".
However, enabling/disabling a "Supply Depot" using signals from a "Road network reader" doesn't work directly, because enabling/disabling the "Supply Depot" immediately changes the signals from the "Road network reader". This results in unintended feedback which makes the circuit state oscillate with each game tick.
This can theoretically be solved with a combinator circuit that subtracts the items in the "Supply depot" from the contents read by the "Road network reader", if and only if the "Supply depot" is enabled. However this is a tricky circuit to get working, and uses a lot of combinators.
Suggestion:
Add a new circuit reader, provisionally called the "Depot Road Reader".
The "Depot Road Reader" behaves as follows:
1) The "Depot Road Reader" attaches to "Supply depots", "Fluid Depots", and "Buffer Depots".
2) If the depot is disabled, the "Depot Road Reader" behaves exactly like a "Road network reader" attached to the same road network.
3) If the depot is enabled, the "Depot Road Reader" behaves like a "Road network reader", except that the contents of the depot are subtracted from the contents of the road network.
The "Depot Road Reader" then directly allows players to control a depot based on "the contents of the road network, excepting the attached depot", which meets the need above.
