Re: Announce: Grace project site operational

[Dmitry A. Kazakov <mailbox@dmitry-kazakov.de>]

On Tue, 14 May 2002 16:03:52 +0100, John English <je@brighton.ac.uk>
wrote:

>"Dmitry A. Kazakov" wrote:
>> 
>> Talking about next revisions and default values, there is another
>> problem with them. How to make a default value private? Let I have
>> some value declared in the private part and I don't want to expose it
>> in the public part. Then there will be no way to use it as a default
>> value in any public thing.
>
>Can't you use a deferred constant for your default value?

It will be visible then! I want not only hide the implementation, but
the very fact that such object exists. Let I have a type with some
reserved values which no user-declared variable or parameter may have.
Like "null" for pointers. Yet some subroutines could have these secret
values as defaults for some parameters. A simple work-around is just
to make several overloaded subroutines from them, which is clumsy.

However, the main argument is not how often one would require that,
but that the information hidding principle is not fully supported for
default values of all sorts [parameters, discriminants].

---
Regards,
Dmitry Kazakov
www.dmitry-kazakov.de