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Hi Doug,
I don't know if I can help but as nobody else has responded yet I'm
willing to give it a try. I'm interested in learning more about the
finer details of issues like this. However, I'm not sure from your
desription that I understand exactly what you are trying to do. Would it
be possible for you to show complete minimal examples of:
a) What you would like the code to look like
b) How you think it needs to be written to make it acceptable to
Blackbox
Regards,
Chris Burrows
CFB Software
http://www.cfbsoftware.com/gpcp
> -----Original Message-----
> From: blackbox{([at]})nowhere.xy> Behalf Of Douglas G. Danforth
> Sent: Wednesday, 13 June 2007 10:22 AM
> To: BlackBox Mailing List
> Subject: [BlackBox] - Hiding abstract methods
>
>
> Folks,
>
> I have a conceptual problem on which I would like your advice.
>
> I have an ABSTRACT type A and two concrete types C1 and
> C2 which are extensions of A.
>
> TYPE
> A* = POINTER TO ABSTRACT RECORD END;
> C1* = POINTER TO RECORD(A) END;
> C2* = POINTER TO RECORD(A) END;
>
> I would like to export A (as shown with the '*'') but within the
> module M where A is defined I *do not want* to export its
> methods. I want them to be completely hidden so that the user
> of M only needs to create the instance Ci (and fill its
> fields (not shown))
> and pass Ci to the module M in which the specific methods
> appropriate to Ci
> are specified (but also not exported). Within M, procedures take 'a'
> (an instance of A which is either C1 or C2) and operates on it without
> knowledge of its concrete form. The methods of A are simply called
> and the concrete forms of those methods as C1 or C2 are actually
> run.
>
> Unfortunately, it seems that this scheme of things is not possible in
> BlackBox.
> I am forced to export the methods of A and also the methods of C1 and
> the methods of C2, greatly cluttering the interface to M when
> none of that
> information will be used by the person operating with M.
> Only the existence
> of A and the extensions C1 and C2 are needed.
>
> Is there a clean way to hide all of these methods?
>
> -Doug Danforth
>
> --- BlackBox
> --- send subject HELP or UNSUBSCRIBE to blackbox{([at]})nowhere.xy--- BlackBox
--- send subject HELP or UNSUBSCRIBE to blackbox{([at]})nowhere.xy
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Received on Thu Jun 14 2007 - 15:58:21 UTC