From: nospam@thanks.com.au (Don Harrison)
Subject: Re: Can't export object of private type
Date: 1999/03/10
Date: 1999-03-10T00:00:00+00:00 [thread overview]
Message-ID: <F8D7xq.HnI@syd.csa.com.au> (raw)
In-Reply-To: m3hfrux6dn.fsf@mheaney.ni.net
Matt Heaney wrote:
:nospam@thanks.com.au (Don Harrison) writes:
:> .. What I
:> really want is an abstract primitive operation, not so much for
:> polymorphism, but so that derivations are forced to supply an access
:> function to their (private) variable "Self". This is a form of
:> contract which derivations must meet.
:
:You can't enforce this using the type system.
I'm beginning to believe that. :(
:This is like declaring a type, and then trying to have an operation that
:forces clients to declare instances of the type. Huh???
Not at all. It's nothing like that. The nature of the inheritance relation
is completely different from the client relation. Whereas a client should
*optionally* use a supplier (including declaring instances of it), a
derivation should be *forced* to honour its parent's contract; otherwise,
polymorphism breaks.
:> Got you. There are two opposing needs here:
:>
:> a) On the other, it's convenient for all private declarations
:> to be in the one place (rather than being split between private
:> part of spec and body)....
:
:I would declare the instance in the body. The reason is that there
:might be other abstractions that are needed by the instance.
:
:If you declare the instance in the spec, then you'll have to move those
:with's into the spec too, which can cause unnecessary recompilations.
Sure.
--
Don (Harrison). donh at syd.csa.com.au
next prev parent reply other threads:[~1999-03-10 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 ` Tom Moran
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 ` Jean-Pierre Rosen
1999-02-27 0:00 ` Simon Wright
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
1999-03-04 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
1999-03-06 0:00 ` robert_dewar
1999-03-04 0:00 ` Can't export object of private type 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 [this message]
1999-03-10 0:00 ` Matthew Heaney
1999-03-04 0:00 ` fraser
1999-03-09 0:00 ` Don Harrison
1999-03-08 0:00 ` 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_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 ` 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 ` robert_dewar
1999-03-11 0:00 ` Don Harrison
1999-03-12 0:00 ` robert_dewar
1999-03-11 0:00 ` Don Harrison
1999-03-10 0:00 ` Robert A Duff
1999-03-10 0:00 ` robert_dewar
1999-03-10 0:00 ` dennison
1999-03-11 0:00 ` dennison
1999-03-03 0:00 ` Don Harrison
1999-02-28 0:00 ` Matthew Heaney
1999-02-28 0:00 ` Matthew Heaney
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