Re: [Fwd: F22 completes 11% of its Flight tests]

[Mark Lundquist <mark@rational.com>]

Richard D Riehle wrote:

> I would agree that _withing_ a vendor supplied package at the
> specification level often reflects poor planning.  Ordinarily,
> one should define the specification required for the problem
> space then _with_ the vendor's package in the package body
> (or even in a separately compiled subpgram) to effect the actual
> implementation.  This accomplishes several things:
>
>      1) The interface is independent of the implementation
>      2) A different implementation can be used to effect the
>         interface,
>      3) Vendor dependencies are hidden from users,
>      4) With Ada 95, we can take advantage of private child units,
>      5) We are more platform-independent.
>
> These are just a few reasons for hiding vendor supplied packages
> when possible.  Granted, it is not always possible or even appropriate.
>
> [...]
>
> So all the fuss about _extensions_ is just that, "fuss."  Experienced
> Ada software designers have been avoiding such dependencies for a
> long time.

Richard, those are good points about using packages to minimize coupling.
But it's quite beside the point of the discussion!  You're talking about
the scope of dependencies, and how to reduce that scope through the use of
proper programming techniques.  The discussion (the "fuss"?) wasn't about
that, it was about the risk to a project of using components supplied by
someone else (e.g. a compiler vendor or a third party).  I.e., about using
them, not hiding vs. exposing them.

(I'm talking now about the last 2-3 messages on this sub-thread... before
that, there were a huge number of messages trying to make sense of the
babblings of some kind of deranged person.  The most fruitless exchange of
messages I've ever seen.  They all pretty much looked like:

            Deranged Person:    @#&$~!   grlb,  flgmrzz!
            Ada Person:            Excuse me?

That was where the "extension" thing came from, but nobody could figure
out what the guy meant, and he finally went away).