Vision2 and the Context-Event-Command-State model

[olivier.ligot]

Hello,

I just read the chapter concerning graphical applications in OOSC2 and found the Context-Event-Command-State model quite interesting.

AFAIK, this model is implemented in the vision library but I can't find it in the Vision2 library. Is the Context-Event-Command-State model present in Vision2 and if yes, how (what are the names of the classes involved)?

Thanks in advance,

Olivier Ligot

[Emmanuel Stapf]

> I just read the chapter concerning graphical applications in OOSC2 and
> found the Context-Event-Command-State model quite interesting.
>
> AFAIK, this model is implemented in the vision library but I can't find
> it in the Vision2 library. Is the Context-Event-Command-State model
> present in Vision2 and if yes, how (what are the names of the classes
> involved)?

This chapter was written with the first revision of EiffelVision in mind. Since
then, EiffelVision had a its second revision embracing the (at the time) new agent
mechanism of the Eiffel language. As a consequence the original model described in
OOSC2 was abandoned. Now when you want to respond to a graphical event, you simply
need to pass an agent that will be called when that event occurred:

my_window.pointer_button_press_actions.extend (agent on_button_click)

Hope this helps,
Manu

[olivier.ligot]

--- In [hidden email], "Emmanuel Stapf [ES]" <manus@...> wrote:
> This chapter was written with the first revision of EiffelVision in mind. Since
> then, EiffelVision had a its second revision embracing the (at the time) new agent
> mechanism of the Eiffel language. As a consequence the original model described in
> OOSC2 was abandoned.

What a shame! One thing that I'm really missing is the STATE abstraction and the associated state machine. Do you know a way to create states in Vision2?

Olivier Ligot