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From: bobduff@world.std.com (Robert A Duff)
Subject: Re: Q: access to subprogram
Date: 1996/07/03
Date: 1996-07-03T00:00:00+00:00	[thread overview]
Message-ID: <Dtyt4K.Jvx@world.std.com> (raw)
In-Reply-To: JSA.96Jul2221357@organon.com


In article <JSA.96Jul2221357@organon.com>,
Jon S Anthony <jsa@organon.com> wrote:
>Is there an "elevator version" of why people didn't want this in?  Tucker,
>if you are reading this, what swayed you to not let this in????  It's
>not one of those things that bothers me all that much (well, it hasn't)
>but it is indeed curious...

There are two major ways of implementing up-level variable references in
a language with nested procedures: Static links, and displays.  With
displays, it is somewhat difficult to implement passing nested
procedures as parameters, because you have to pass the display, which is
not of compile-time-known size.  Passing a static link is easy -- it's
just a single address.  Some implementations of Ada 83 used displays.
The primary reason for not putting the feature in was to ease the pain
for such implementations.  This was done at a time when the general
feeling was that Ada 9X had more than enough new features, and we
shouldn't be adding things, but removing them.

- Bob




  reply	other threads:[~1996-07-03  0:00 UTC|newest]

Thread overview: 133+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
1996-07-02  0:00 Q: access to subprogram tmoran
1996-07-02  0:00 ` Robert A Duff
1996-07-02  0:00   ` Robert Dewar
1996-07-03  0:00   ` Fergus Henderson
1996-07-03  0:00     ` Robert A Duff
1996-07-03  0:00       ` Adam Beneschan
1996-07-03  0:00         ` Robert Dewar
1996-07-03  0:00         ` Robert A Duff
1996-07-09  0:00         ` Thomas Wolff
1996-07-03  0:00       ` Robert Dewar
1996-07-03  0:00   ` Jon S Anthony
1996-07-03  0:00     ` Robert A Duff [this message]
1996-07-08  0:00       ` Norman H. Cohen
1996-07-09  0:00         ` Robert A Duff
1996-07-03  0:00     ` Mark A Biggar
1996-07-03  0:00       ` Robert A Duff
1996-07-03  0:00         ` Robert Dewar
1996-07-09  0:00         ` Thomas Wolff
1996-07-09  0:00           ` Robert Dewar
1996-07-10  0:00           ` Robert A Duff
1996-07-10  0:00             ` Richard A. O'Keefe
1996-07-10  0:00               ` Robert A Duff
1996-07-10  0:00                 ` Thomas Wolff
1996-07-10  0:00                   ` Robert A Duff
1996-07-10  0:00                   ` Robert Dewar
1996-07-10  0:00               ` Robert Dewar
1996-07-03  0:00       ` Robert Dewar
1996-07-06  0:00         ` Robert A Duff
1996-07-08  0:00           ` Norman H. Cohen
1996-07-08  0:00             ` Robert Dewar
1996-07-11  0:00             ` Robert A Duff
1996-07-12  0:00               ` Robert A Duff
1996-07-14  0:00               ` Norman H. Cohen
1996-07-03  0:00     ` Robert Dewar
1996-07-19  0:00     ` Brian Rogoff
1996-07-22  0:00       ` Richard A. O'Keefe
1996-07-23  0:00       ` Brian Rogoff
1996-07-23  0:00         ` Robert A Duff
1996-07-26  0:00         ` Brian Rogoff
1996-07-28  0:00           ` Robert A Duff
1996-07-22  0:00     ` Brian Rogoff
1996-07-23  0:00       ` Robert A Duff
1996-07-24  0:00       ` Richard A. O'Keefe
1996-07-26  0:00         ` Ken Garlington
1996-07-30  0:00           ` Richard A. O'Keefe
1996-07-24  0:00       ` Brian Rogoff
1996-07-26  0:00         ` Robert A Duff
1996-07-30  0:00         ` Brian Rogoff
1996-07-24  0:00     ` Brian Rogoff
1996-07-26  0:00     ` Richard A. O'Keefe
1996-07-28  0:00       ` Robert A Duff
1996-07-29  0:00         ` Richard A. O'Keefe
1996-07-29  0:00           ` Robert A Duff
1996-07-28  0:00       ` Fergus Henderson
1996-07-29  0:00     ` Richard A. O'Keefe
1996-07-30  0:00     ` Jon S Anthony
1996-07-05  0:00   ` Jon S Anthony
1996-07-06  0:00     ` Robert A Duff
1996-07-06  0:00       ` Robert Dewar
1996-07-08  0:00         ` Robert A Duff
1996-07-08  0:00       ` Richard A. O'Keefe
1996-07-08  0:00         ` Robert Dewar
1996-07-10  0:00           ` Richard A. O'Keefe
1996-07-10  0:00             ` Robert Dewar
1996-07-19  0:00               ` Richard A. O'Keefe
1996-07-08  0:00         ` Robert A Duff
1996-07-08  0:00           ` Robert Dewar
1996-07-06  0:00     ` Robert Dewar
1996-07-07  0:00   ` Ronald Cole
1996-07-07  0:00     ` Richard Kenner
1996-07-07  0:00     ` Robert Dewar
1996-07-07  0:00       ` Richard Kenner
1996-07-07  0:00         ` Robert Dewar
1996-07-14  0:00       ` Ronald Cole
1996-07-14  0:00         ` Richard Kenner
1996-07-15  0:00           ` Fergus Henderson
1996-07-15  0:00             ` Robert Dewar
1996-07-17  0:00               ` Fergus Henderson
1996-07-17  0:00                 ` Richard Kenner
1996-07-17  0:00               ` Adam Beneschan
1996-07-20  0:00               ` Michael Feldman
1996-07-20  0:00                 ` Robert Dewar
1996-07-16  0:00             ` Richard Kenner
1996-07-07  0:00   ` Mark Eichin
1996-07-08  0:00     ` Richard Kenner
1996-07-08  0:00   ` Brian Rogoff
1996-07-11  0:00     ` Norman H. Cohen
1996-07-11  0:00       ` Magnus Kempe
1996-07-11  0:00         ` Robert Dewar
1996-07-09  0:00   ` Jon S Anthony
1996-07-09  0:00     ` Robert Dewar
1996-07-09  0:00     ` Robert Dewar
1996-07-09  0:00   ` Jon S Anthony
1996-07-09  0:00     ` Robert Dewar
1996-07-10  0:00   ` Ronald Cole
1996-07-11  0:00     ` Richard Kenner
1996-07-11  0:00     ` Robert Dewar
1996-07-11  0:00   ` Jon S Anthony
1996-07-11  0:00     ` Robert Dewar
1996-07-11  0:00   ` Jon S Anthony
1996-07-11  0:00   ` Jon S Anthony
1996-07-11  0:00     ` Tucker Taft
1996-07-17  0:00       ` Brian Rogoff
1996-07-11  0:00     ` Robert Dewar
1996-07-15  0:00       ` Mark A Biggar
1996-07-15  0:00         ` Robert Dewar
1996-07-12  0:00     ` Jon S Anthony
1996-07-12  0:00       ` Robert Dewar
1996-07-15  0:00     ` Jon S Anthony
1996-07-15  0:00       ` Robert Dewar
1996-07-12  0:00   ` Brian Rogoff
1996-07-16  0:00     ` Magnus Kempe
1996-07-14  0:00   ` Ronald Cole
1996-07-14  0:00     ` Robert Dewar
1996-07-15  0:00   ` Jon S Anthony
1996-07-15  0:00     ` Robert Dewar
1996-07-16  0:00   ` Brian Rogoff
1996-07-24  0:00 ` Jon S Anthony
1996-07-25  0:00 ` Jon S Anthony
1996-07-25  0:00 ` Fergus Henderson
1996-07-25  0:00   ` David Kristola
1996-07-26  0:00     ` Robert A Duff
1996-07-30  0:00       ` David Kristola
1996-07-30  0:00       ` Thomas Wolff
1996-07-30  0:00         ` Robert A Duff
1996-07-26  0:00   ` Robert A Duff
1996-07-26  0:00     ` Fergus Henderson
1996-07-28  0:00       ` Robert A Duff
1996-07-28  0:00         ` Fergus Henderson
  -- strict thread matches above, loose matches on Subject: below --
1996-07-05  0:00 tmoran
1996-07-06  0:00 ` Robert A Duff
1996-07-15  0:00 tmoran
1996-07-15  0:00 ` Robert Dewar
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