That depends on what version of Pharo you use.

In Pharo 1.4 you can use SystemChangeNotifier to do something like this:

SystemChangeNotifier uniqueInstance

notify: toSomeObject

ofSystemChangesOfItem: #class

change: #Added

using: #someMethod:.

then if a new class is added to the system, SystemChangeNotifier will call #someMethod: on toSomeObject, passing an Event to #someMethod:. You can browse the code on SystemChangeNotifier to see all the notification you can use, and the package "System-Change Notification" to see the events you can receive.

In Pharo 2.0 you can do the same thing using SystemAnnouncer:

SystemAnnouncer uniqueInstance

on: ClassAdded

send: #someMethod:

to: toSomeObject.

You can see the different announcements you can use on browsing the package "System-announcements". In this example #someMethod: will receive an announcement.

I want to do some logic when there is a change on the system, like when a new class is loaded or when a method change. I don't want to put this logic explicit on the methods of the system who do that. I would like to know if i could subscribe to those special events (method change, new method, changes on a class and so on) so I can do what I want outside those methods.

I heard about the Announcements but I don't know if Announcements could help with this problem.

Can anyone give me some highlights to do those things?

Thanks!

(I'm really trying with my english, hope it's understandable)

--
Miguel Enrique Campusano Araya

Estudiante de Ingenier��a Civil en Computaci��n

Universidad de Chile