Re: GNAT versions ( was :Ada compiler for PC?)

[mrs@kithrup.com (Mike Stump)]

>I still find the documentation of the exception handling stuff
>in GCC inadequate.

Well, feel free to donate improvements to the documentation, gcc
always welcomes clarifications and more complete explanations.  :-)
I'd be happy to answer your questions about it.

>One unfortunate consequence is that the GNAT exception handling has
>been developed entirely independently,

Well, I take exception to the word entirely.  There was a mailing list
called eh@cygnus.com, and we discussed tons of details and issues,
from many language perspectives, including Ada and C++.

This experience shaped and drove my implementation, the implementation
that now exists in gcc.

I would anticipate that it did the same for the Ada implementation.
If true, they are closely related.

>I suspect that there could be more merging,

Sure, each front end can replicate it's own exception scheme[1], but
this is a poor design.  A better design is where the common aspects of
the design are shared by the frontends as facilities in the backend.
C++ and Java already share EH.  Chill needs to be converted, but there
is no pressing need, as not to many people use or maintain it.

:-)  Yes, I know you already knew that.  I say it, just to nag a little,
in hopes that Ada will embrace the functionality that is now there and
extend it.

>because to have an exception handling mechanism usable by both C++
>and Ada 95, a perfectly reasonable goal, would require careful
>examination of the specifications *before* starting to implement.

:-)  Yes, and that was done to a large extent.  The missing pieces are
meant to slot into the existing design, in a natural way.


1 - Actually, my experience is that this is not possible, that is
    _why_ EH is now in gcc.  The frontend implementation could only
    go so far, then things like flow, really wanted to know more and
    understand more.