Re: Ada OO Mechanism

[Laurent Guerby <guerby@acm.org>]

Hyman Rosen <hymie@prolifics.com> writes:
> [...]
> From a little fooling around with your code above
> and gnat, and the Rationale, it looks like the compiler has to examine
> the code that attempts to initialize a T'Class variable and allocate
> the maximum space for it that that code would require. C++ doesn't do
> any of that - C++ coders would be using dynamic allocation and pointers
> or references to pass around arbitray subclasses. Interesting. [...]

I think most Ada implementation use a secondary stack where such
dynamix sized beasts are built, there's no need for "maximum space"
allocation. Note that this feature of Ada is not linked to OO, the
same mechanism is in place for function returning dynamically sized
arrays. Of course the cost of this is spurious copying if the compiler
isn't very clever.

--LG