Re: Sugestion to Multiple Inheritance

[Brian Rogoff <bpr@bpr.best.vwh.net>]

No problem! It may be worthwhile for someone to resuscitate the RPI SGL
library, which is based on the STL. When last I checked, it was still a
bit buggy, and I would prefer to avoid controlled types except when
necessary, but there were some good ideas there, and (at least in C++) I
prefer the generic approach to the OO approaches.

IMHO OOP is not as important as the programming world has made it out to
be, and should be used a lot less than it is.

-- Brian

On Mon, 21 Jan 2002, Lutz Donnerhacke wrote:

> * Brian Rogoff wrote:
> >Yes, generics can do exactly that. Do you understand the signature idiom
> >in Ada 95?
>
> Now I start to understand. Thanx.
>
> >What you don't get, that tagged types give you, is the same kind of
> >polymorphism at run time. You pay for that run time capability with run
> >time dispatch and the overhead of tagging.
>
> Of course. I was looking for an abstraction require a full instantiation.
> Generics does this a small step later than abtract tagged types. (Besides
> using tagged types for saving multiple implementations.) Without class wide
> programming there is no run-time overhead, but a storage one.
>
> >So you parameterize over a forward iterator signature, which looks
> >something like this
> >
> >generic
> >    type Value_Type (<>) is limited private;
> >    type Pointer_Type is access Value_Type;
> >    type Iterator_Type is private;
> >
> >    with procedure Incr (Iterator : in out Iterator_Type) is <>;
> >    with function Succ (Iterator : in Iterator_Type)
> >                       return Iterator_Type is <>;
> >    with function Get_Value (Iterator : Iterator_Type)
> >                            return Value_Type is <>;
> >    with procedure Set_Value (Iterator : in out Iterator_Type;
> >                              Value : in Value_Type) is <>;
> >    with function Get_Pointer (Iterator : Iterator_Type)
> >                              return Pointer_Type is <>;
> >    with function "=" (X, Y : Iterator_Type)
> >                        return Boolean is <>;
> >package Forward_Iterator_Signature is
> >-- Look, no body! This is a signature package.
> >end Forward_Iterator_Signature;
>
> Understand. Thank you. This seems to be the way Booch is working.
>