Re: Derived private interface

["Randy Brukardt" <randy@rrsoftware.com>]

"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message 
news:1luxw3i4h9z8e$.7a8ee3cf99u2.dlg@40tude.net...
> On Wed, 10 Aug 2011 16:56:00 -0500, Randy Brukardt wrote:
>
>> "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message
>> news:1bs0xoar40rx.6yb23bgkfrew.dlg@40tude.net...
>
>>> In reality
>>> there are many dispatching calls and many class-wide operations (for 
>>> which
>>> there is no typed procedural equivalent).
>>
>> Reality? The reality is in the web server interface I was describing 
>> there
>> was only one such point of dispatch, and only a single interface to 
>> dispatch
>> to. It's clearly a special case, but one that is pretty common in the
>> systems I've worked on.
>
> The problem is that starting a project without OO, you have to gamble on
> whether this indeed is a special case and will remain special.
>
> This is called fragile design.

No, this is called "agile development"! There is no circumstance where a 
designer can possibly predict all possible ways their project is going to 
evolve. It's silly to try.

It doesn't matter how you design your interfaces -- you're going to have to 
change them at some point. And I've never seen any difference in the amount 
of work in a OOP design. If anything, the OOP designs are harder to 
modify -- adding a new interface to the ARM formatter or the Claw Builder 
takes a long time and requires inserting a lot of similar code in a number 
of packages. I've rarely seen that sort of behavior with a purely procedural 
design (probably because ad-hoc sharing of code is much easier in a 
procedural design).

I could imagine that there could exist some extremely fancy tools for 
creating the common structures of all of those "implementations" of the new 
interfaces automatically -- but I'm not aware of any such thing for Ada --  
and in any case, I wouldn't have one (I only use Janus/Ada tools for 
[virtually all] programming here; have to do so in order to figure out what 
needs to be improved).

                                   Randy.