Re: Implementing C/C++ style #include...

["Marin David Condic" <marin.condic.auntie.spam@pacemicro.com>]

Dead code optimization was brought up in another sub-thread. I agree that
this is a good trick suitable for many of the things usually done by
preprocessors.

If one is willing to live with a rather primitive preprocessor, it might not
be that big a job to simply recognize some simple markers and
comment/uncomment code (or just remove it) as needed for test. Its just that
it usually isn't long before someone wants to have somewhat more
sophisticated features available.

Its like I said: How much work do you want to do? I don't think there are
enough benefits from a preprocessor to make it worth the time it would take
to develop one. I understand that your garden variety C/C++ programmer is
used to having one around and may want to lean on one for comfort while
moving into The Ada Way(tm). (Hacking C code in Ada syntax, as it were.)

I just distrust this sort of add-on to a language and I think Ada is rich
enough to get the job done without a preprocessor. If a programmer is used
to thinking in terms of lexical inclusion rather than semantic inclusion,
preprocessors behave more the way they are used to working. If you make the
mental shift into packages, generics, "with" statements, etc., you probably
won't feel the need to rely on preprocessors since you'll evolve mechanisms
to do the same job in The Ada Way.

MDC
--
Marin David Condic
Senior Software Engineer
Pace Micro Technology Americas    www.pacemicro.com
Enabling the digital revolution
e-Mail:    marin.condic@pacemicro.com
Web:      http://www.mcondic.com/


"Ira D. Baxter" <idbaxter@semdesigns.com> wrote in message
news:tbk5cb2rf5aef0@corp.supernews.com...
> One can take advantage of dead code optimization
> to eliminate conditionally-compiled code.  So you
> don't really need a preprocessor for that.
>
> There isn't any standard in Ada for conditional compilation
> of data declarations (or even pragmas!).  This
> is probably enough to justify a preprocessor of some kind.
>
> Building one out of conventional tools such as YACC
> is probably pretty hard.  You can certainly hack
> a simple one in PERL, if you want, by defining
> it to operate on lines that start with #, say.
>
> However, if you want one integrated with the Ada source,
> you could do that pretty easily by augmenting
> an Ada grammar with a few rules, and
> using a transformation engine such as our DMS Reengineering Toolkit
> (see http://www.semdesigns.com/Products/DMS/DMSToolkit.html).
> DMS can be obtained with an Ada grammar.
> Rewrite rules for simplifying boolean equations are pretty
> easy, as are rules that eliminate conditionals conditioned by TRUE or
FALSE.
> Such rules coupled with boolean conditions would
> give an Ada preprocessor with only small effort.
>
> --
> Ira D. Baxter, Ph.D. CTO Semantic Designs, Inc.
> http://www.semdesigns.com
>
> "Marin David Condic" <marin.condic.auntie.spam@pacemicro.com> wrote in
> message news:99alrr$itf$1@nh.pace.co.uk...
> > "bhazzard" <bhazzard@email.msn.com> wrote in message
> > news:OrZxgIisAHA.289@cpmsnbbsa09...
> > > A quick question...
> > >
> > > Is there any way to implement c/c++ style
> > > #ifdef pre-processor statements in Ada.
> > >
> > There is always a way. If you're willing to do the work yourself, you
can
> > write a program to parse your Ada code to look for preprocessor
directives
> &
> > output appropriate *new* Ada code before doing the compile. This is a
lot
> of
> > work
>
>