Re: Ada Annex E (Just curious :-)

[Robert A Duff <bobduff@world.std.com>]

"Marin David Condic" <marin.condic.auntie.spam@pacemicro.com> writes:

> What you're saying is that you'd do some sort of extension to System.RPC and
> fill in the read/write/do_rpc stuff? The dispatching handles the rest? That
> would go a long way to making it fairly easy to modify the behavior to get
> what you want.

Package RPC is just an interface -- the package spec defines the
interface between the compiler's generated code and the lower-level
message-passing stuff.  The Ada programmer writes the *body* of this
package.  (The compiler writer can provide one or more bodies, of
course, but it doesn't have to.)

Given that the semantics of this interface are defined in the RM, having
the user write this body does not constitute hacking on the compiler's
internals, as you seemed to think before.

You should read RM-E.5.  Also DR-8652/0087 (that's paragraph
E.5(24.1/1-24.2/1) in the October 2000 version of the AARM -- the one
with DR's inserted).

The other problem you mentioned is non-portability of the
representations supported by 'Read and 'Write; their default behavior is
implementation defined, so in a heterogeneous environment, you will have
to write your own.  I wish we had been more ambitious, and designed more
built-in support for heterogeneous systems.  In this "internet age",
that would be a pretty cool thing.

> In general, I've not been 100% happy with the behavior of streams and the
> 'Read & 'Write stuff.

I must admit: there were many language design mistakes in this area:
look at all the AI's that came out of this section.

- Bob