Re: Java vs Ada 95 (Was Re: Once again, Ada absent from DoD SBIR solicitation)

[dewar@merv.cs.nyu.edu (Robert Dewar)]

Jon Anthony said

"I've seen you mention this before.  It is depressing.  Putting it in
an annex of its own would probably have been even nicer (and from what
you say, even less likely).  Really.  This is a pretty sad and
incomprehensible story."


Not incomprehensible at all, it just means the world does not agree with
you, or at least the world of people involved and interested in the Ada
95 design. When I argue for something, and everyone else disagrees, I
don't go around mumbling "sad and incomprehensible", I just figure I
was wrong!

In this particular case, the feeling was that including GC in the IS
annex would make the annex too difficult to implement, which, since
it is optional, might be counter  productive.

There could have been an annex for GC, but no one was interested enough
to suggest that, and if they had, I don't think it would have interested
people enough to survive.

Just because you want something in Ada and not many other people do does
not mean the majority is wrong and you are right :-)

Now, as I have noted before, I think Java may change people's attitude
towards GC (in fact I think this is really the only interesting thing
about Java that is really new).

Note that in saying from a formal point of view that whether a language
does or does not have GC, we are being a little too pedantic in one
important respect.

If you have a language like Algol-68 or (as far as I know, I am not an
expert) Java, that has no way of explicitly freeing storage, then from
a practical point of view, you have no way of implementing the language
(assuming it does have dynmaic allocation explicitly or implicitly, without
using garbage collection).

To get a feel for the orginal intent in Ada (which was that typical
implementations would have GC), note that although NEW is clearly a
first class citizen in Ada, and is introduced early on in the RM,
the corresponding FREE operation is buried in chapter 13 and given
a disparaging name (unchecked_deallocation). Just as the thought was
that most programs would not need to use unchecked conversion, the 
thought was that most programs would not need to use unchecked
deallocatoin, because GC would be there.

Well maybe this is a little overreaching :-)
\x1adp