Re: SDL-News: Virtual type


Subject: Re: SDL-News: Virtual type
From: Fabrice DUBOIS - FTRD/DTL/MSV (fabrice.dubois#rd.francetelecom.fr)
Date: Wed May 03 2000 - 13:17:51 GMT


helene le wrote:

> The originator of this message is responsible for its content.
> -----From =?iso-8859-1?q?helene=20le?= <helene_leguen#yahoo.com> to sdlnews -----
>
> Hello,
>
> I am looking for information about the virtual process
> type :
> What does it mean?
> How can I create an entity of the process?
>
> Thank you,
>
> =====
> ____________________________
> Helene Le Guen
> Societe Alitec
> Maison de la technopole
> 6 rue Leonard de Vinci
> 53000 Laval
>
> __________________________________________________
> Do You Yahoo!?
> Talk to your friends online and get email alerts with Yahoo! Messenger.
> http://im.yahoo.com/
>
> -----End text from =?iso-8859-1?q?helene=20le?= <helene_leguen#yahoo.com> to sdlnews -----
> Join http://www.sdl-forum.org/Society/members.htm for extra SDL Forum Society benefits
> For help, email "majordomo#sdl-forum.org" with the body of your email as:
> help
> or (iff this does not answer your question) email: owner-sdlnews#sdl-forum.org

Hello Hélène,

Suppose you define a block type BT1 that contains a process type P, and one instance of P.
Now you make another block type BT2, which inherits from BT1. In that new block type, you
want to add a process instance X, and to connect it to the inherited instance of P.
Unfortunatly, you realise that your instance of P is not able to handle some signals that are
sent by X :-(
Since you can't change the fact that the instance is of type P, the solution is to REDEFINE -
in BT2 - the type P itself (by adding transitions for example, and by adding/modifying a
gate).

Now we come to the following conclusion: to enable redefinitions of P, it's necessary to make
it a VIRTUAL process type in the original BT1.
This is a typical example of usage of virtuality with entity types.

Instances of VIRTUAL process types are created exactly the same way 'NORMAL' process types
are.

    PROCESS <instName>:<type>

NOTE - Any entity type in SDL 96 must be well formed and complete enough so that instances
can be made of it. There is no "pure virtuality" or abstraction mecanism to prevent someone
from creating instances of a type. But SDL 2000 now provides such a mecanism
(keyword:ABSTRACT).

Regards,
Fabrice

// Fabrice Dubois
// france telecom r&d [dtl/msv]
// fabrice.dubois#rd.francetelecom.fr

helene le wrote:

The originator of this message is responsible for its content.
-----From =?iso-8859-1?q?helene=20le?= <helene_leguen#yahoo.com> to sdlnews  -----

Hello,

I am looking for information about the virtual process
type :
What does it mean?
How can I create an entity of the process?

Thank you,

=====
____________________________
Helene Le Guen
Societe Alitec
Maison de la technopole
6 rue Leonard de Vinci
53000 Laval

__________________________________________________
Do You Yahoo!?
Talk to your friends online and get email alerts with Yahoo! Messenger.
http://im.yahoo.com/

-----End text from =?iso-8859-1?q?helene=20le?= <helene_leguen#yahoo.com> to sdlnews -----
Join http://www.sdl-forum.org/Society/members.htm for extra SDL Forum Society benefits
For help, email "majordomo#sdl-forum.org" with the body of your email as:
    help
or (iff this does not answer your question) email: owner-sdlnews#sdl-forum.org

Hello Hélène,

Suppose you define a block type BT1 that contains a process type P, and one instance of P.
Now you make another block type BT2, which inherits from BT1. In that new block type, you want to add a process instance X, and to connect it to the inherited instance of P. Unfortunatly, you realise that your instance of P is not able to handle some signals that are sent by X :-(
Since you can't change the fact that the instance is of type P, the solution is to REDEFINE - in BT2 - the type P itself (by adding transitions for example, and by adding/modifying a gate).

Now we come to the following conclusion: to enable redefinitions of P, it's necessary to make it a VIRTUAL process type in the original BT1.
This is a typical example of usage of virtuality with entity types.

Instances of VIRTUAL process types are created exactly the same way 'NORMAL' process types are.

    PROCESS <instName>:<type>

NOTE - Any entity type in SDL 96 must be well formed and complete enough so that instances can be made of it. There is no "pure virtuality" or abstraction mecanism to prevent someone from creating instances of a type. But SDL 2000 now provides such a mecanism (keyword:ABSTRACT).

Regards,
Fabrice

// Fabrice Dubois
// france telecom r&d [dtl/msv]
// fabrice.dubois#rd.francetelecom.fr
  -----End text from Fabrice DUBOIS - FTRD/DTL/MSV to sdlnews -----



This archive was generated by hypermail 2a23 : Thu May 09 2013 - 16:05:49 GMT