Re: Rep Spec Report with ASIS

["Jeffrey Creem" <jeff@thecreems.com>]

Another approach for an ASIS implementation that does not support this
capability (data representation section)
would be to create an ASIS program who's output is a program that creates
the output you want....
I have not done so there may be a few snags but in principal it seems like
could be done.
Of course it is more work than I've ever wanted (or been paid :) to
undertake.


"Robert Dewar" <dewar@gnat.com> wrote in message
news:5ee5b646.0202021451.226fab4@posting.google.com...
> "John Cupak" <Jcupak744@mediaone.net> wrote in message
news:<PMS68.69384$Ln2.15233029@typhoon.ne.mediaone.net>...
> >
> > So, I thought that there might be an ASIS program someone out there in
> > "Ada Land" has written that might provide the information requested. I
would
> > think it wouldn't be terribly hard to walk throught the declarations,
find
> > record
> > type definitions, and generate a Representation Specification Report for
> > each
> > one - would it?
>
> It would be virtually impossible unless the ASIS port you
> are using supports the data representation section of the
> ASIS standard, and this support is of course keyed to a
> particular compiler. However, as far as I know, ASIS-for-GNAT is the
> only implementation of ASIS that
> supports this optional capability.
>
> The reason that this is virtually impossible is
>
> a) you would have to duplicate the entire data layout algorithms of
> the compiler you are using, these algorithms
> are often extremely extensive and complex.
>
> b) you would have to know what these algorithms are. I don't think any
> compiler has sufficiently complete documentation to reliably duplicate
> the data layout for
> this purpose.
>
> We find that the -gnatR report that GNAT Pro can provide is
> extremely useful, and a number of our customers very much
> rely on this tool. The advantage here is that the compiler
> is generating this information directly from the internal
> data structures after laying out the data, so the output
> from -gnatR is by definition exactly correct.
>
> So basically you are out of luck here if you are not using
> GNAT. Why not talk to your vendor and see if they can do
> something for you -- perhaps they have some equivalent
> internal tools that they can be persuaded to cough up.
>
> (I say that because we find -gnatR enormously useful for
> our support activities, and it is hard for me to imagine
> how one would deal with things if you could not easily
> tell how the compiler was laying things out).
>
> Robert Dewar
> Ada Core Technologies