Reactor vs non reactor

I've spend time to read about reactor,but not yet enough to satisfied,I
don't know where we start to learn reactor ,I only want ask to others .What
is different a program autolisp contained reactor and non reactor?

 

Hi Luis, I thought
1. visual lisp reactor more higher level than visual lisp code
2. with reactor can do anything and complex
3. visual lisp has limited solution,visual lisp reactor unlimited solution

or in imaginable
1. visual lisp reactor = car with abs
2. visual lisp = car without abs (conventional)

 

Chapter 7 -- Advanced Topics
VLISP not only makes program development easier and faster, it also provides
new functionality to AutoLISP applications. For example, you can attach
reactors to entities in the AutoCAD drawing window, allowing your
application to respond to user actions on these entities.

 

Chapter 7 -- Advanced Topics
To add reactor functionality to your application, you first need to write a
callback function that performs the tasks needed at the time of the reactor
event. After you define a callback function, you link the function to an
event by creating a reactor object


Is it true a "callback" as "ent',and then replace "notifier-object" by "ent"

(vl-load-com)
(setq ss (ssget))
(setq en (ssname ss 0))
(setq ent (vlax-ename->vla-object en))

For example, the following code defines a callback function named
print-radius. This function can be used to print the radius of a circle:

(defun print-radius (notifier-object reactor-object parameter-list)
(vl-load-com)
(cond ( (vlax-property-available-p notifier-object "Radius" )
(princ "The radius is ")
(princ (vla-get-radius notifier-object))
)
)
)