On Fri, 23 Jan 1998, Emmanuel BEUQUE wrote:
> >I see no problems with OctetString<->ContentRef because internaly the
> >ContentReference is only an OctetString, too (please help me, I can't
> >remember the heavy discussions about the conversions anymore...:(.
> >With Integer<->Boolean it is a problem: what is the Integer representation
> >of the Boolean value?
> >What about Integer<->ObjectRef (or OctetString<->ObjectRef)? This is even
> >more a problem because you either loose something in the conversion process
> >or make assumptions about the format of the ObjectReference.
>
> My idea here is to provide very easy use of any variable like some other
> languages do (if condition of C language for instance).
> As you stated, some conversions I suggested cannot be bidirectional without
> loosing some information. But I think this kind of conversion could be
> useful in some cases anyway.
>
> [many very good thoughts]
As Xavier statet, MHEG-5 is not a classic programming language but more a
description of objects and behaviour. Not every feature should be integrated
just because it makes life simpler.
> This kind of features could even be provided by MHEG without defining the
> rules of conversion but letting it to the application domain. That's what
> is done for the StorePersistent/ReadPersistent actions for instance.
What do you mean? The format of how the objects are stored internally is
not an issue of the Application domain but to the implementor of an
engine.
> Integer->Boolean :
> Suppose you want to return a feedback of the state of listGroup. In fact
> you want to inform the user if one or several items of a listGroup are
> selected. Suppose you manage a counter with 2 links. ItemSelected increment
> the counter by one, ItemDeselected decrement it. Then you could convert
> this counter value to a boolean and use it to set the Highlight status of
> an Interactible.
You can do this whith one or two more links and a TestEvent.
> Integer->ObjectRef
> Suppose you have to do some actions to a set of visible, for instance
> stopping all the items of a tokenGroup. Suppose the object numbers of this
> items are serialized, from 1 to 20 for instance. Then you could do the
> following (The syntax is used for readability but is not conformed to MHEG
> IS)
> [Example deleted]
All you need here is a counter variable and, again, a series of TestEvent
links.
Best regards,
Andreas
-- o _ Andreas Kraft (\_|_) GMD FOKUS, kraft@fokus.gmd.de, +49 30 3463-7232 T> ] [ The sky is the limit