Re: Ada Objects Help!

[nebbe@lglsun.epfl.ch (Robb Nebbe)]

In article <1995Jan20.134150@hobbit>, hathawa2@marshall.edu (Mark S. Hathaway) writes:


|> Then the Ada example changes 'myclass(int)' to 'Create(X : Integer) return T'
|> with the added complexity of defining T.  It looks wrong or overly complex.
|> And it's comparable in length to the C++ version only because the class
|> implementation isn't given.

Ada doesn't have constructors so a function returning the type is what
you would use. Defining T isn't any more complex it is just longer. Ada
provides a more general approach by separating types and modules. To
get the same level of generality C++ has nested classes.

|> Does the Ada example even create an object?

Yes, but not on the heap.

|> Here's my idea of how it should look.

(example deleted) I don't see any big difference. You have a complete
separation of implementation and interface but that implies that you
are going to work with more levels of indirection or you are going
to perform what is often considered as code generation at link time.

There are many aspects of both Ada and C++ that are in the language not
so much because they are the best way to do it from some theroretical
perspecitve but because of practical reasons such as "what do
compiler writers know how to do well?" and "what do operating systems
currently support?"

Robb Nebbe