Re: Imitation is the sincerest form of flattery

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

On Tue, 25 Mar 2003 15:22:10 -0500, Hyman Rosen <hyrosen@mail.com>
wrote:

>Dmitry A. Kazakov wrote:
>> Array is an old well known concept, which requires no baroque kinks.
>
>There are many old and well-known concepts.
>Good programming languages allow you to build
>them yourself instead of providing special
>and unique support.

I know such a language, one of the Turing machine. (:-))

>> Right, but not in C++, which is unable to handle unconstrained objects on 
>> the stack.
>
>True enough for now. I suspect C++ will eventually adopt a
>form of C99's variable-length arrays, and then it will be
>possible. Where supported, something could probably be
>cobbled together with alloca.
>
>> But as you said it should not be slow.
>
>OO-style inheritance is the wrong concept for this.

Wrong for what? There is no other way to specify a type set other than
through closures of a subtyping relation. That's what inheritance is
about.

>> your nasty proxy class will show itself.
> > you will have to make it derived
>
>Nope. The function will be a generic, instantiated
>automatically on the proxy class.

Let you declare:

   void Foo (Element& X);

then A[i] have to be of Element type to allow substitutability:

   Foo (A [i]);

If A [i] is of some proxy class then you need ether to make the class
a subtype of Element, or to write a wrapper for Foo.

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