Re: OOD, Ada, and Inheritance

[saimiri.primate.wisc.edu!zaphod.mps.ohio-state.edu!cis.ohio-state.edu!new s.sei.cmu.edu!ajpo.sei.cmu.edu!wellerd@ames.arc.nasa.gov (David Weller)]

In article <mmaccorm.47@fox.nstn.ns.ca> mmaccorm@fox.nstn.ns.ca (Mike Mac Corma
ck) writes:
>If Ada software is being designed using OOA and OOD, should inheritance be 
>avoided (or prohibited) in the design process, as Ada does not provide 
>inheritance? 
>

There are many projects being build in Ada that are applying OOD.
The project that I am on, the Space Station Verification and
Training Facility, is applying both OOA and OOD.  It is definitely
a non-trivial project, with an estimated total SLOC count of
2 million (I think SLOC is such a useless metric for government
projects, wouldn't "Pounds of Documentation" be more useful? :-)

Our inheritance is "manual", employing pass-through calls and
composition to simulate "real" inheritance.  This is very deliberate,
since we intend to quickly transition to Ada 9X, which will support
inheritance and run-time dispatching.  In the 30 year life of this
project, we felt that the early manual implementation of inheritance
would give bigger payoffs than choosing to ignore that feature.

It seems silly to sacrifice a design to fit in a current language.
Especially when you know that language will support those
"prohibited" features in about 2 years.


---- I can't speak for my company.  Not until I get this damn gag off!-------
David Weller,         | Space Station Training Facility: Like the real
CAE-Link,             | thing, only you can step outside for a breath
Space Technology Div. | of fresh air!
----I'm the Ultimate International Masochist: I speak Ada AND Esperanto!-----