Re: Teaching C/C++ from Ada perspective?

[Maciej Sobczak <see.my.homepage@gmail.com>]

> But I'll say that examples involving empty packages and useless withs don't 
> really prove anything regardless of the language involved

Fair point.

> - they're not very 
> realistic.

Empty packages are not, but useless withs quite well reflect the rotting of the codebase during its evolution and refactoring. The whole pimpl idiom (as it is known in the C++ community, but practiced in Ada, too, under the "opaque pointer" name) exists exactly to reduce the number of compile-time dependencies. In the case of my previous example, if you find a way to move the useless "with P" from the Q's spec to its body, then you can gain a lot in terms of this reduction (in particular, Test becomes no longer dependent on P). This phenomenon is very real and proactive application of such techniques is essential to effective physical design. This applies to both Ada and C++.

> I'd suggest looking at examples of privacy (which Ada is very 
> strict about) and comparing to other languages (which I don't know well 
> enough to do myself).

Good point, but here I will argue that Ada does not have any recognizable added value with regard to C++ - that is, I think I am able to translate any typical Ada privacy structure into equivalent C++ definitions. What is interesting in this area, however, is that in large projects I can actually expect that the privacy policies will be intentionally (!) reduced, for example with unit testing and run-time inspection in mind. Yes, it is possible to avoid this, but it is costly and the cheaper option wins. This observation applies to all static languages.

-- 
Maciej Sobczak * http://www.inspirel.com