Re: GNAT and subunits

[mfeldman@seas.gwu.edu (Michael Feldman)]

In article <D69I6D.nF@inmet.camb.inmet.com>,
Tucker Taft <stt@spock.camb.inmet.com> wrote:
>Robert Dewar (dewar@cs.nyu.edu) wrote:

>:    1. If a parent unit is compiled with subunits missing, then revert
>: 	automatically to -gnatc mode, complaining that "no code is
>: 	generated because subunits are missing" or somesuch.

>Sounds like a good idea.  You probably want to make it a warning instead
>of an error, or else it will scare people.

I agree with Tucker. I think this is a good idea.

>:    2. Change the default of the binder to -s mode, we have been considering
>: 	this for a while.
>
>: I would particularly be interested in people's reactions to suggestion 2.

I think the difficulties some folks have had is that, while the -gnat
options to gcc, and those of gnatbl, are quite well documented in the 
"user guide" known as gnatinfo.txt, the options of gnatbind do not
appear ajywhere in that document. This is, I'm sure, an oversight and
can easily be rectified. In the meantime, Robert pointed out to me
that typing "gnatbind" by itself will produce a list of the options.

>I think you should make the binder default "-s" to minimize the likelihood
>of "pilot" error.  This also seems most compatible with the "conventional"
>Ada library model.
>
>-Tucker Taft   stt@inmet.com
>Intermetrics, Inc.

Again I think Robert and Tucker have put their finger on it. When it comes
to new or casual users, and especially users who are not new to Ada but are
new to GNAT, IMHO GNAT's various _default_ options should be as safe as
possible and as intuitive as possible, even if (as in the case of -s)
there is some performance penalty.

As is the case with all software, really experienced GNAT users, and
those with multi-language compilations, etc., will figure out the
optimal combination of options and encapsulate them in makefiles,
scripts, etc. For GNAT newbies writing "conventional" Ada code, there
should be as few surprises as possible in using simple commands with
default options.

It's clear to me that the GNAT team is sensitive to these matters and
working on the right solutions.

Mike Feldman