Overview

Reactors are part of the Visual LISP event model.

A reactor is a host-side event-callback subscription object. The host calls the registered callback automatically whenever a documented event occurs (entity modified, document opened, command executed, sysvar changed, mouse-down, …). Reactors are the AutoLISP equivalent of "event listeners" in GUI frameworks and the "observer pattern" in OOP, layered over a fixed reactor type taxonomy that the vendor reference ties to specific event classes.