From: "Nick Roberts" <Nick.Roberts@dial.pipex.com>
Subject: Re: Abstract Subprograms of Untagged Types
Date: 1999/03/05
Date: 1999-03-05T00:00:00+00:00 [thread overview]
Message-ID: <7brero$gb9$1@plug.news.pipex.net> (raw)
In-Reply-To: 36E04AA7.4CB8F686@averstar.com
Tucker Taft wrote in message <36E04AA7.4CB8F686@averstar.com>...
[...]
|One reason we allow abstract primitives of an untagged type
|is because one way to *disable* a particular primitive
|that is inherited is to override it with an abstract primitive.
Aha!
[...]
|> and I would like to see the restrictions introduced in the next
|> revision of Ada.
|
|At this point, this seems very unlikely, since someone may
|be quite happily taking advantage of the ability to declare
|abstract primitives of an untagged type.
Accepted.
[...]
|> things, but they should give a warning (or error) when they can tell the
|> programmer has (almost certainly) done something silly.
|
|Identifying things that are harmless but silly can be difficult
|and is probably more trouble than it is worth in most cases.
|Identifying things that are likely to cause a run-time error
|seems much more valuable.
I would agree that good warnings are often hard to encode, and that foolish
warnings are as annoying as negligent omissions of warnings. I suspect that
it would be useful for a compiler to give a warning under some
circumstances, when an abstract subprogram is declared. Do you disagree?
If not, would you be kind enough to suggest what situations would be
appropriate for a warning? Possibly, for example, whenever the subprogram
has no tagged parameter or return type, and none of any of its parameter or
return types is derived from a type which has, as a primitive operation, a
matching subprogram which is not itself abstract. Perhaps it might be
appropriate to include a recommendation of such warnings in a future
revision?
|-Tucker Taft stt@averstar.com http://www.averstar.com/~stt/
|Technical Director, Distributed IT Solutions (www.averstar.com/tools)
|AverStar (formerly Intermetrics, Inc.) Burlington, MA USA
-------------------------------------
Nick Roberts
-------------------------------------
next prev parent reply other threads:[~1999-03-05 0:00 UTC|newest]
Thread overview: 128+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <F7JoCB.JxB@syd.csa.com.au>
1999-02-24 0:00 ` Can't export object of private type Don Harrison
1999-02-24 0:00 ` Samuel Mize
1999-02-24 0:00 ` Tucker Taft
1999-02-25 0:00 ` Don Harrison
1999-02-25 0:00 ` Samuel Mize
1999-02-26 0:00 ` Don Harrison
1999-02-27 0:00 ` Nick Roberts
1999-03-01 0:00 ` Don Harrison
1999-03-01 0:00 ` Nick Roberts
1999-03-01 0:00 ` Don Harrison
1999-03-02 0:00 ` Matthew Heaney
1999-03-03 0:00 ` Don Harrison
1999-03-03 0:00 ` Samuel Mize
1999-03-04 0:00 ` Don Harrison
1999-03-07 0:00 ` Ehud Lamm
1999-03-01 0:00 ` Matthew Heaney
1999-03-01 0:00 ` Nick Roberts
1999-03-03 0:00 ` Robert A Duff
1999-03-04 0:00 ` Don Harrison
1999-03-04 0:00 ` Robert A Duff
1999-03-01 0:00 ` Don Harrison
1999-03-02 0:00 ` Matthew Heaney
1999-02-28 0:00 ` Matthew Heaney
1999-03-01 0:00 ` Nick Roberts
1999-03-01 0:00 ` Matthew Heaney
1999-03-01 0:00 ` Matthew Heaney
1999-03-02 0:00 ` Nick Roberts
1999-03-01 0:00 ` Samuel Mize
1999-02-25 0:00 ` fraser
1999-02-26 0:00 ` Don Harrison
1999-02-26 0:00 ` Samuel Mize
1999-03-01 0:00 ` Don Harrison
1999-03-01 0:00 ` Matthew Heaney
1999-03-02 0:00 ` fraser
1999-03-03 0:00 ` Don Harrison
[not found] ` <7b6nqe$75m$1@remarq.com>
1999-02-26 0:00 ` fraser
1999-02-27 0:00 ` Nick Roberts
1999-02-26 0:00 ` fraser
1999-03-01 0:00 ` Don Harrison
1999-03-01 0:00 ` Matthew Heaney
1999-02-28 0:00 ` Matthew Heaney
1999-02-28 0:00 ` Matthew Heaney
1999-02-25 0:00 ` robert_dewar
1999-02-26 0:00 ` Don Harrison
1999-02-26 0:00 ` robert_dewar
1999-02-26 0:00 ` dennison
1999-02-26 0:00 ` bourguet
1999-02-26 0:00 ` Samuel T. Harris
1999-02-27 0:00 ` Simon Wright
1999-02-27 0:00 ` Jean-Pierre Rosen
1999-02-28 0:00 ` dewar
1999-03-01 0:00 ` bourguet
1999-03-01 0:00 ` Don Harrison
1999-03-01 0:00 ` robert_dewar
1999-03-03 0:00 ` Don Harrison
1999-03-03 0:00 ` robert_dewar
1999-03-01 0:00 ` Stephen Leake
1999-02-27 0:00 ` Brian Rogoff
1999-03-01 0:00 ` robert_dewar
1999-02-28 0:00 ` Matthew Heaney
1999-03-01 0:00 ` Tom Moran
1999-03-02 0:00 ` Matthew Heaney
1999-03-02 0:00 ` Tom Moran
1999-03-02 0:00 ` Matthew Heaney
1999-03-02 0:00 ` Tom Moran
1999-03-02 0:00 ` Matthew Heaney
1999-03-02 0:00 ` nabbasi
1999-03-02 0:00 ` Matthew Heaney
1999-03-03 0:00 ` Don Harrison
1999-03-03 0:00 ` Single Extension; Polymorphic Arrays Nick Roberts
1999-03-03 0:00 ` Nick Roberts
1999-03-08 0:00 ` Matthew Heaney
1999-03-08 0:00 ` Nick Roberts
1999-03-08 0:00 ` Tucker Taft
[not found] ` <m3ogm40wav.fsf@mheaney.ni.net>
1999-03-08 0:00 ` Tucker Taft
1999-03-08 0:00 ` dennison
1999-03-09 0:00 ` Nick Roberts
1999-03-08 0:00 ` Nick Roberts
1999-03-03 0:00 ` Can't export object of private type Don Harrison
1999-03-03 0:00 ` Don Harrison
1999-03-03 0:00 ` Nick Roberts
1999-03-04 0:00 ` Don Harrison
1999-03-04 0:00 ` Nick Roberts
1999-03-08 0:00 ` Matthew Heaney
1999-03-09 0:00 ` Don Harrison
1999-03-09 0:00 ` Matthew Heaney
1999-03-09 0:00 ` Nick Roberts
1999-03-10 0:00 ` Don Harrison
1999-03-10 0:00 ` Matthew Heaney
1999-03-04 0:00 ` fraser
1999-03-09 0:00 ` Don Harrison
1999-03-04 0:00 ` Nick Roberts
1999-03-04 0:00 ` robert_dewar
1999-03-05 0:00 ` Nick Roberts
1999-03-05 0:00 ` Robert A Duff
1999-03-05 0:00 ` Abstract Subprograms of Untagged Types Nick Roberts
1999-03-05 0:00 ` robert_dewar
1999-03-05 0:00 ` Tucker Taft
1999-03-05 0:00 ` Nick Roberts [this message]
1999-03-06 0:00 ` robert_dewar
1999-03-08 0:00 ` Can't export object of private type Matthew Heaney
1999-03-08 0:00 ` Nick Roberts
1999-03-08 0:00 ` Matthew Heaney
1999-03-10 0:00 ` Don Harrison
1999-03-10 0:00 ` Matthew Heaney
1999-03-10 0:00 ` dennison
1999-03-10 0:00 ` Robert A Duff
1999-03-10 0:00 ` dennison
1999-03-11 0:00 ` dennison
1999-03-10 0:00 ` robert_dewar
1999-03-10 0:00 ` robert_dewar
1999-03-10 0:00 ` dennison
1999-03-10 0:00 ` robert_dewar
1999-03-10 0:00 ` dennison
1999-03-11 0:00 ` dennison
1999-03-11 0:00 ` robert_dewar
1999-03-11 0:00 ` Don Harrison
1999-03-12 0:00 ` robert_dewar
1999-03-11 0:00 ` bill
1999-03-11 0:00 ` Scott Ingram
1999-03-11 0:00 ` Larry Kilgallen
1999-03-11 0:00 ` dennison
1999-03-12 0:00 ` dewar
1999-03-11 0:00 ` Don Harrison
1999-03-03 0:00 ` Don Harrison
1999-02-28 0:00 ` Matthew Heaney
1999-02-24 0:00 ` Tom Moran
1999-02-28 0:00 ` Matthew Heaney
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