The Dialog/Control ADT question

From: [at]} <Wojtek>
Date: Mon, 30 Jun 2003 21:34:04 -0400 (EDT)

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Hi:

  I have a somewhat provocative question whether it is possible at all
to make an abstract data type dealing with Dialogs, such that this
ADT would be able to take advantage of Controls. The entire Dialog
module seems to be setup with records, not pointers to records.
The intended use of Dialogs is to declare a static global variable,
fill it with data, and then pass the name "module.variable" to the
Controls. The Controls will use Meta to search for the variable
under the hood, using the ingenious Meta wizard, and somehow the
Dialog data will be visible on-screen.

This is great. But now I want to make a free-floating View the usual
BlackBox way. I can create a view which will have a Dialog variable
as its data field. This variable can be either a pointer or just
a record, no problem. I can fill this variable with data. And then what?
How do I pass this variable to Controls.Control such that the control
will link itself to my free-floating viewer, whose content is accessible
only via string of pointers?

The problem seems to be that Controls.Control does not define any
method which would take a pointer to a Dialog variable. It only takes
the name of the variable in the form "module.name", and then locates
the variable using Meta. I guess I want to ask whether there is a more
direct way to establish the link Dialog <--> Control than with passing
a string. Using a pointer would accomplish this. But it does not seem
to be defined.

Can you see what I am aiming at? Does this make a good sense to be
able to construct views which would show Controls linked to the local
view variables?

This all appears in the context of making the Dialog.Tree persistent.
I am trying to accomplish a view, which would show a visible tree Control,
and which I can store to disk like any other view, with the underlying
Dialog tree _and_ with objects pointed to by the Dialog TreeNodes.
I guess this is a perfectly legimate thing to do. But I am now stuck
with the above problem.

I am not insisting on that solution. Maybe there is more sensible way,
though it looks to me the above is legitimate. If not, why not, and how
to accomplish the goal of storing the Dialog.Tree _and_ its pointees?
Gerard has suggested a possible solution using Meta and SYSTEM, which we
both seem to dislike. Also, his solution requires a global variable,
because he is using Meta. Thus it only works for such singletons.
How about a general ADT? Possible, or not?

Cheers,

Wojtek Skulski skulski{([at]})nowhere.xy

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Received on Tue Jul 01 2003 - 03:34:04 UTC