Interruption

A vehicle has stopped and cannot carry on by itself.

Sealed, because what a modeller may need to know differs by cause while everything they need to decide is the same: where the vehicle is, what it is holding, what it was doing, and who is now stuck behind it. The guide path draws no distinction at all -- a flat battery, a breakdown and an operator stopping the line are one event to it -- so the distinction lives here, where the response is decided.

An interruption is handed to the vehicle's InterruptionPolicyIfc, which runs as a process and may do anything a process may do: wait for a technician, delay for travel and assessment, tow the vehicle out of the way. The policy has no return value. When it returns, the framework asks the same question the movement gate asks -- is this vehicle fit to carry on? -- and acts on the answer. A repair that finished leaves a repaired vehicle, so it continues; a charge policy that did nothing leaves a flat vehicle, so it does not. One predicate, and no way for a policy to claim it fixed something it did not.

Inheritors