From: jsa@alexandria.synquiry.com (Jon S Anthony)
Subject: Re: limited/non-limited in Ada95
Date: 1997/10/21
Date: 1997-10-21T00:00:00+00:00 [thread overview]
Message-ID: <JSA.97Oct20202120@alexandria.synquiry.com> (raw)
In-Reply-To: mheaney-ya023680001810971145040001@news.ni.net
In article <mheaney-ya023680001810971145040001@news.ni.net> mheaney@ni.net (Matthew Heaney) writes:
> I don't understand Henry's problem. If I implement a bank account as
The problem he points out in the paper is quite clear IMO.
> I agree that aliasing can comprimise the safely of a limited type (everyone
> ought to read Baker's Limited Robbery paper), but if the programmer always
> implements a limited private type by using a full view that is itself
> limited - which one can do in Ada 95 - then there is no problem.
There are important cases where this is at _best_ impractical and
actually is more like not _feasible_. The _view_ for the
implementation should not (can _not_) have limited semantics. This is
particularly evident when you are constructing GC for Ada _within_ the
language. Since this is one of Henry's main baileywicks, and since
I've constructed such a GC asset suite _within_ the language, I can
very easily understand where he is coming from. It's _painfully_
obvious when you have to actually deal with the situation.
> If the programmer doesn't use a by-reference type, then it's a case of
> programmer indolence, not a language problem.
Rubbish.
/Jon
--
Jon Anthony
Synquiry Technologies, Ltd., Belmont, MA 02178, 617.484.3383
"Nightmares - Ha! The way my life's been going lately,
Who'd notice?" -- Londo Mollari
next prev parent reply other threads:[~1997-10-21 0:00 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
1997-10-13 0:00 limited/non-limited in Ada95 Tom Moran
1997-10-16 0:00 ` Matthew Heaney
1997-10-17 0:00 ` Jon S Anthony
1997-10-18 0:00 ` Tom Moran
1997-10-18 0:00 ` Matthew Heaney
1997-10-19 0:00 ` Tom Moran
1997-10-19 0:00 ` Matthew Heaney
1997-10-21 0:00 ` Tom Moran
1997-10-21 0:00 ` Matthew Heaney
1997-10-21 0:00 ` Robert A Duff
1997-10-18 0:00 ` Matthew Heaney
1997-10-21 0:00 ` Jon S Anthony [this message]
1997-10-21 0:00 ` Robert A Duff
1997-10-22 0:00 ` Jon S Anthony
1997-10-23 0:00 ` Fergus Henderson
1997-10-23 0:00 ` Jon S Anthony
1997-10-24 0:00 ` Geert Bosch
1997-10-23 0:00 ` Jon S Anthony
1997-10-22 0:00 ` Robert Dewar
1997-10-22 0:00 ` Jon S Anthony
1997-10-21 0:00 ` Robert Dewar
1997-10-21 0:00 ` Jon S Anthony
1997-10-22 0:00 ` Robert Dewar
1997-10-22 0:00 ` Jon S Anthony
1997-10-21 0:00 ` Robert A Duff
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