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From: tmoran@bix.com
Subject: Re: Naming of Tagged Types and Associated Packages
Date: 1998/07/26
Date: 1998-07-26T00:00:00+00:00	[thread overview]
Message-ID: <6pfs36$8rh@lotho.delphi.com> (raw)

>The addition of tagged types in Ada 95 is good, but it doesn't change
>implementation techniques that much from Ada 83, because you should
>already be using type-based abstractions where that makes sense.
  There are some things Ada 95 lets you do that were *extremely*
inconvenient, in Ada 83.  Controlled types, which let a task execute
code after an "or terminate" select alternative, and "access T'Class"
which lets you link heterogenous data simply, come to mind.  For a
slightly more complex example, a system I'm working on has a
library-level task and task safety (and the OS, in this case) requires
that certain things only be done by that task.  Occasionaly, we've
needed to add a new operation.  At first we added a new 'entry' and
recompiled the world.  Then we realized that there can be one entry
that takes a classwide parameter and calls a standard "Do_Whatever"
procedure, passing that parameter.  Now a new operation merely
requires a new descendant of the (abstract) root type with appropriate
information in the new extension part, and an overriding "Do_Whatever"
that will be run from the correct task.  No spec changes to the task
and thus no recompilation.  Tagged types are a new tool.  There's no
requirement to limit their use to what the designers, or OO
philosophy, intended.




             reply	other threads:[~1998-07-26  0:00 UTC|newest]

Thread overview: 135+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
1998-07-26  0:00 tmoran [this message]
1998-07-27  0:00 ` Naming of Tagged Types and Associated Packages dennison
  -- strict thread matches above, loose matches on Subject: below --
1998-07-16  0:00 taashlo
1998-07-25  0:00 ` Matthew Heaney
1998-07-25  0:00   ` Jean-Pierre Rosen
1998-07-25  0:00     ` Brian Rogoff
1998-07-26  0:00       ` Matthew Heaney
1998-07-26  0:00     ` Matthew Heaney
1998-07-26  0:00       ` nabbasi
1998-07-26  0:00         ` Matthew Heaney
1998-07-26  0:00         ` Robert Dewar
1998-07-27  0:00       ` Jean-Pierre Rosen
1998-07-28  0:00         ` Matthew Heaney
1998-07-28  0:00           ` Jean-Pierre Rosen
1998-07-28  0:00             ` dennison
1998-07-29  0:00               ` Jean-Pierre Rosen
1998-07-29  0:00                 ` dennison
1998-07-29  0:00                   ` Jean-Pierre Rosen
1998-07-30  0:00                     ` dennison
1998-07-30  0:00                       ` Jean-Pierre Rosen
1998-07-29  0:00         ` Robert I. Eachus
1998-07-30  0:00           ` Jean-Pierre Rosen
1998-07-30  0:00             ` Robert I. Eachus
1998-07-31  0:00               ` Jean-Pierre Rosen
1998-07-31  0:00                 ` Robert I. Eachus
1998-08-01  0:00                   ` Jean-Pierre Rosen
1998-08-04  0:00                     ` Matthew Heaney
1998-08-04  0:00                       ` Jean-Pierre Rosen
1998-08-10  0:00                         ` Robert I. Eachus
1998-07-30  0:00           ` Matthew Heaney
1998-07-27  0:00       ` dennison
1998-07-27  0:00         ` Stephen Leake
1998-07-27  0:00           ` dennison
1998-07-27  0:00             ` Brian Rogoff
1998-07-28  0:00               ` dennison
1998-07-28  0:00                 ` Brian Rogoff
1998-07-28  0:00                   ` dennison
1998-07-29  0:00                     ` Matthew Heaney
1998-07-29  0:00                       ` Chris Brand
1998-07-30  0:00                         ` Matthew Heaney
1998-07-30  0:00                           ` dennison
1998-07-30  0:00                             ` Matthew Heaney
1998-07-30  0:00                               ` dennison
1998-08-01  0:00                           ` Simon Wright
1998-08-02  0:00                             ` Matthew Heaney
1998-08-03  0:00                               ` dennison
1998-08-03  0:00                                 ` Matthew Heaney
1998-08-04  0:00                                   ` dennison
1998-08-04  0:00                               ` Jean-Pierre Rosen
1998-08-04  0:00                                 ` Brian Rogoff
1998-08-05  0:00                               ` Don Harrison
1998-08-05  0:00                                 ` Matthew Heaney
1998-08-07  0:00                                   ` Don Harrison
1998-08-13  0:00                                     ` Robert A Duff
1998-08-14  0:00                                       ` Don Harrison
1998-08-14  0:00                                       ` adam
1998-08-05  0:00                                 ` Brian Rogoff
1998-08-07  0:00                                   ` doylep
1998-08-07  0:00                                     ` Brian Rogoff
1998-08-08  0:00                                       ` Matthew Heaney
1998-08-10  0:00                                       ` doylep
1998-08-10  0:00                                         ` Brian Rogoff
1998-08-10  0:00                                           ` John Volan
1998-08-10  0:00                                           ` John Volan
1998-08-11  0:00                                           ` doylep
1998-08-11  0:00                                             ` Brian Rogoff
1998-08-13  0:00                                               ` Robert A Duff
1998-08-13  0:00                                                 ` Brian Rogoff
1998-09-01  0:00                                                 ` Matthew Heaney
1998-09-01  0:00                                                   ` Dale Stanbrough
1998-09-01  0:00                                                     ` Matthew Heaney
1998-09-01  0:00                                                       ` Bob Collins
1998-09-02  0:00                                                         ` Matthew Heaney
1998-09-04  0:00                                                       ` John G. Volan
1998-08-11  0:00                                         ` Don Harrison
1998-08-11  0:00                                           ` Pat Rogers
1998-08-11  0:00                                             ` Don Harrison
1998-09-01  0:00                                               ` Matthew Heaney
1998-08-13  0:00                                         ` Robert A Duff
1998-08-13  0:00                                           ` Brian Rogoff
1998-08-15  0:00                                             ` Don Harrison
1998-08-15  0:00                                               ` Jean-Pierre Rosen
1998-08-18  0:00                                                 ` Don Harrison
1998-08-14  0:00                                           ` Don Harrison
1998-08-17  0:00                                             ` doylep
1998-08-19  0:00                                               ` Don Harrison
1998-08-12  0:00                                       ` Don Harrison
1998-08-08  0:00                                     ` Matthew Heaney
1998-08-08  0:00                                       ` John G. Volan
1998-08-09  0:00                                         ` Matthew Heaney
1998-08-10  0:00                                           ` John G. Volan
1998-08-11  0:00                                             ` John Volan
1998-08-11  0:00                                             ` Don Harrison
1998-08-11  0:00                                               ` geoff
1998-08-31  0:00                                             ` Matthew Heaney
1998-08-31  0:00                                               ` Tucker Taft
1998-09-06  0:00                                                 ` John G. Volan
1998-09-06  0:00                                                   ` Matthew Heaney
1998-09-04  0:00                                               ` John G. Volan
1998-09-05  0:00                                                 ` Matthew Heaney
1998-09-05  0:00                                                   ` John G. Volan
1998-09-04  0:00                                               ` John G. Volan
1998-09-06  0:00                                                 ` Matthew Heaney
1998-09-06  0:00                                                   ` John G. Volan
1998-09-06  0:00                                                     ` Brian Rogoff
1998-09-06  0:00                                                       ` John G. Volan
1998-09-07  0:00                                                         ` Brian Rogoff
1998-09-07  0:00                                                           ` John G. Volan
1998-09-16  0:00                                                             ` Matthew Heaney
1998-09-06  0:00                                                   ` John G. Volan
1998-09-04  0:00                                               ` John G. Volan
1998-09-05  0:00                                                 ` John G. Volan
1998-09-06  0:00                                                   ` Matthew Heaney
1998-09-06  0:00                                                 ` Matthew Heaney
1998-09-05  0:00                                               ` John G. Volan
1998-09-05  0:00                                               ` John G. Volan
1998-08-11  0:00                                       ` doylep
1998-08-07  0:00                                   ` Don Harrison
1998-07-28  0:00                   ` Brian Rogoff
1998-07-29  0:00                     ` Matthew Heaney
1998-07-29  0:00                       ` Brian Rogoff
1998-07-28  0:00             ` Norman H. Cohen
1998-07-28  0:00               ` Stephen Leake
1998-07-28  0:00               ` Matthew Heaney
1998-07-28  0:00         ` Matthew Heaney
1998-07-28  0:00           ` Jean-Pierre Rosen
1998-07-28  0:00             ` Matthew Heaney
1998-07-28  0:00               ` dennison
1998-07-29  0:00                 ` Matthew Heaney
1998-07-30  0:00                 ` Robert Dewar
1998-07-30  0:00                   ` Matthew Heaney
1998-08-06  0:00         ` Robert A Duff
1998-08-06  0:00           ` Matthew Heaney
1998-08-06  0:00             ` Tucker Taft
1998-08-31  0:00               ` Matthew Heaney
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