Re: friend classes in ada95 (long)

[Ole-Hjalmar Kristensen <ohk@clustra.com>]

Brian Rogoff <bpr@shell5.ba.best.com> writes:

> On 24 Apr 2000, Hyman Rosen wrote:
> > Brian Rogoff <bpr@shell5.ba.best.com> writes:
> > > It seems that I ruffled your feathers by using that word in the context of 
> > > your favorite language. Sorry. I actually liked the signature extension of 
> > > C++. I'd love to see such a feature grafted onto Ada.
> > 
> > Sorry about that. My antennae sometimes get a little hyperextended in
> > c.l.a. 
> 
> You'll probably have to develop a thicker skin, or tougher antennae,  
> because this is com.lang.ada after all. I'm similarly annoyed by the 
> gratuitous C++ slamming, even though I prefer Ada to C++ for most tasks, 
> but that's the nature of comp.lang.*
> 
> > But as to signatures, I don't much care for them. It seems to
> > me that they are there to take advantage of accidents in function
> > naming, whereas interfaces are part of a design.
> 
> Is that from actual use, or just reading and inference? I don't have any 
> real data myself, I just read about GNU C++ signatures. I did use Sather 
> for a while, which also had a powerful signature-like mechanism that 
> permitted the addition of signatures (types in Sather parlance) above 
> an existing class. This feature was mainly used to define type bounds in 
> generic classes. Since C++ doesn't have constrained parametric
> polymorphism (yes, I know how to simulate it inelegantly in C++) this
> isn't as important there. 
> 
> The real revolutionary aspect of standard C++ which I wish Ada would copy
> is automatic generic/template instantiation. I think the modification to
> Ada (read "An Ada like language") would be better off omitting the full
> power of templates to do compile time calculations, and therefore omitting 
> "template metaprogramming", but would still enhance Ada's abilities in a 
> number of interesting ways. 
> 
> -- Brian
> 
> 

Yes, I think it's sensible to restrict the power of templates, at
least from an implementation view. I've seen so many C++ compilers
that either fail to compile, or generate wrong code for complex
templates. I still feel I cannot really trust C++ templates.

-- 
E pluribus Unix