Constructs an editor reactor that notifies of a command event

(vlr-command-reactor data callbacks)



Any AutoLISP data to be associated with the reactor object; otherwise nil if no data is to be associated with the reactor.


A list of pairs of the following form:

(event-name . callback_function)

where event-name is one of the symbols listed in the “Command reactor events” table below, and callback_function is a symbol representing a function to be called when the event fires. Each callback function accepts two arguments:

reactor_object The VLR object that called the callback function.

list A list containing a single element, the string identifying the command.

Return Values

The reactor_object argument.

Command reactor events

Event name



A command not known to AutoCAD was issued.


An AutoCAD command has been called.


An AutoCAD command has completed.


An AutoCAD command has been canceled.


An AutoCAD command failed to complete.