Re: Typing in Ada

["Nick Roberts" <nick.roberts@acm.org>]

"Peter C. Chapin" <pchapin@sover.net> wrote in message
news:Xns94FAD66E1E08Bpchapinsovernet@207.106.92.237...

> ...
> It's not clear to me how all this relates to the concept of strong
> typing.

I think technically strong typing is about explicit type conversion, so
that:

   A := O;
   ... A+O ...

is not permitted, and one has to write:

   A := Apples(O);
   ... A+Apples(O) ...

instead. I think this is the definition generally adopted in computer
science.

> I guess it would be helpful to have a precise definition of that term.
> It sounds like from what we've said here that strong typing more a
> matter of programming style than a language feature ...

I would certainly say that that is where it matters. It doesn't matter if a
programmer language has some wonderful feature if, in practice, nobody ever
uses it.

> ... at least where C and Ada are concerned. Is that a valid
> conclusion?

It seems reasonable to suppose that if C had always included a convenient
facility for introducing differentiated types, this facility would have been
used in practice. I think you will find the following paper (it's a PDF)
very interesting with regard to the ongoing arguments about introducing such
a facility to SQL:

   http://www.jeffsutherland.com/x3h2/97-094.pdf

-- 
Nick Roberts