Trigger/event system (scripting lite)

AFAIK, scripts are often not allowed, or not even working properly on MP servers.

For a "scripting lite", there should be a simple event-based trigger system that can be used for automation. This could be for example a "trigger block", that listens to events fired by a block it is facing, and activates something (a door, a timer block, etc.) when it receives one. For simplicity, the activation could only activate on a) a certain event or b) any event, ie. one activation only per block. For more complex setups (if allowed), a trigger could face another trigger, and react to a specific event with a specific activation.

Different blocks could fire different kinds of events: almost everything would fire an on/off event when switched. Moving parts could fire events when activated, when reaching min/max, when reversed, etc. Solar panels could emit events when their power level changes.

This could be as simple or complex as desired, with the main requirement being that it should function more reliably, securely etc. than scripting. Something that every server could choose to allow, and not suffer too high a performance hit.