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From: "Rodrigo Garcia" <rodrigo.garcia@epfl.ch>
Newsgroups: comp.lang.ada
References: <3E37E080.3080608@epfl.ch> <ud6mfvioo.fsf@nasa.gov>
 <x7visw62wwu.fsf@smaug.pushface.org>
Subject: Re: Streams and Access types
Date: Fri, 31 Jan 2003 12:13:09 +0100
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"Simon Wright" <simon@pushface.org> wrote in message
news:x7visw62wwu.fsf@smaug.pushface.org...
> Stephen Leake <Stephen.A.Leake@nasa.gov> writes:
>
> > Rodrigo Garc�a <rodrigo.garcia@epfl.ch> writes:
> >
> > >    One solution is to do custom serialization but, does anybody knows
> > > of an Ada compiler that can automatically serialize the objects
> > > pointed by access variables (recursively if needed, such in the case
> > > of the linked list)?
> >
> > This is not possible in general. How would the compiler resolve a
> > circular list? All doubly-linked lists have circles, so it is a real
> > problem.
>
> Clearly this can be done! Java does it (unless I'm mistaken). You have
> to keep track of what's been serialized already, I suppose.

    You are right. Java does it by assigning a "handle" (a number starting
at 0x7E0000) that identifies each serialized object. If the object is
referenced again, Java serializes just its handle.

    There is a problem with this though. If the object is modified and sent
again through the same stream, it will be identified by its handle and this
will not reflect the modifications. You have to restart the stream in order
to serialize the object again.

    Anyway, I only wanted to know if there is already an Ada compiler that
does something similar.

Rodrigo