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From: eachus@spectre.mitre.org (Robert I. Eachus)
Subject: Re: Naming of Tagged Types and Associated Packages
Date: 1998/07/30
Date: 1998-07-30T00:00:00+00:00	[thread overview]
Message-ID: <EACHUS.98Jul30161618@spectre.mitre.org> (raw)
In-Reply-To: 6ppc3q$8ju$1@platane.wanadoo.fr


  I said:

 > Ah, but I always find myself doing the following:...
 >
 > So both the use clause issue, and the meaningful name issue go away.

In article <6ppc3q$8ju$1@platane.wanadoo.fr> "Jean-Pierre Rosen" <rosen.adalog@wanadoo.fr> writes:

 >  I discussed the drawbacks of this approach in my paper
 > (http://perso.wanadoo.fr/adalog/naming9x.zip, now includes the ppt version
 >  thanks Ted Dennison).
 > Basically: forces you to use empty extension aggregate. If the package
 > declares other stuff (like secondary types) you must reexport it manually.

  This is where we will have to leave it.  I don't find adding "with
null" offensive, and I usually do need to access secondary types, but
the only sane way to do it is with a qualified names because there may
be several types of that name (often the same one) in the derivation stack.

  A VERY simplified example:

  with Ada.Finalization;
  package People is 

    type Person is tagged private;

    function Name(Who: in Person) return String;
    procedure Set_Name(Who: in out Person; Name: in String);
    function Address(Who: in Person) return String;
    function Set_Address(Who: in out Person; Address: in String);
    ...

  private

    package Add_Name is new Unbounded_String_Component(
           Ada.Finalization.Controlled);
    package Add_Address is new Unbounded_String_Component(
           Add_Name.Record_Type);
    type Person is new Add_Address.Record_Type with null;

    pragma Inline(Name, Set_Name, Address, Set_Address);

  end People;

  Now in the body I'll have to write things like:

    function Name(Who: in Person) return String is
    begin return Add_Name.Get(Who); end Name;

  I can't use a renaming as body, because Get takes a classwide
parameter so I don't get driven crazy by adding conversions.  Yes, you
can use dispatching, but when you have twenty or so instantiations, it
gets seriously confusing.

  why go to all the "trouble" required to build object classes like
this?  Because the operations required to display an object with
dynamic updating and other niceties comes with the component packages.
--

					Robert I. Eachus

with Standard_Disclaimer;
use  Standard_Disclaimer;
function Message (Text: in Clever_Ideas) return Better_Ideas is...




  reply	other threads:[~1998-07-30  0:00 UTC|newest]

Thread overview: 138+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
1998-07-16  0:00 Naming of Tagged Types and Associated Packages 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       ` 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                   ` Brian Rogoff
1998-07-29  0:00                     ` Matthew Heaney
1998-07-29  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                                   ` Don Harrison
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                                             ` Don Harrison
1998-08-11  0:00                                               ` geoff
1998-08-11  0:00                                             ` John Volan
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                                                 ` John G. Volan
1998-09-06  0:00                                                   ` Matthew Heaney
1998-09-06  0:00                                                 ` Matthew Heaney
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                                                   ` 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
1998-09-04  0:00                                               ` John G. Volan
1998-09-05  0:00                                                 ` Matthew Heaney
1998-09-05  0:00                                                   ` John G. Volan
1998-09-05  0:00                                               ` John G. Volan
1998-09-05  0:00                                               ` John G. Volan
1998-08-11  0:00                                       ` doylep
1998-08-05  0:00                           ` Static Polymorphism (Was Re: Naming of Tagged Types...) Brian Rogoff
1998-08-06  0:00                             ` Matthew Heaney
1998-08-06  0:00                               ` Brian Rogoff
1998-07-28  0:00             ` Naming of Tagged Types and Associated Packages Norman H. Cohen
1998-07-28  0:00               ` Matthew Heaney
1998-07-28  0:00               ` Stephen Leake
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
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           ` Matthew Heaney
1998-07-30  0:00           ` Jean-Pierre Rosen
1998-07-30  0:00             ` Robert I. Eachus [this message]
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
  -- strict thread matches above, loose matches on Subject: below --
1998-07-26  0:00 tmoran
1998-07-27  0:00 ` dennison
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