Re: Is strong typing worth the cost?

[Darren New <dnew@san.rr.com>]

"Chad R. Meiners" wrote:
> Changing requirements would require changing the auditing code which I would
> gather is alot more costly than changing type information.

Well, no, that's kind of the point. It's cheaper to change the auditing
code than it is to change the type information, due to the way the whole
process (including the language) is set up. 

> > You figure the cost of everything it takes to write the program that
> > meets the requirements under realistic requirements.
> 
> Invalid! (well mostly ;) How do we know the costs are related to strong or
> weak typing?  It could be that program A satisfies an unrequested
> requirement that doubles the cost of development.

"Doctor, Doctor! It hurts when I do this!"
    "Well, don't do that!"

Of course you would have to know that your goal is to minimize the
development effort, and therefore satisfying a number of unrequested
requirements that take a great deal of work to satisfy is Bad.

>  I realize that your
> realistic requirements MIGHT TRY to address this issue, but the better the
> requirements the closer your programs get to being the same which is the
> only way you can do a truly valid comparison. 

Well, I don't think it's reasonable to try to develop a program without
strong typing in Ada. It just doesn't make sense, because Ada is
strongly typed. You *can't* develop a weakly-typed program in Ada. So
you would have to compare Ada against a weakly-typed language (or a
dynamically-typed language) as a comparison, at which point your two
programs won't be the same. Your requirements, of course, would have to
deal with input and output, rather than program structure.

And of course, the OP asked for some actual evidence, rather than lots
of handwaving about why strong typing *should* be better. There's
actually empirical evidence that dynamic typing is better in some
situations, and one can point to many convincing theoretical reasons for
strong typing being safer, and there are a number of axes to measure
along, so I don't think there's any one answer.

-- 
Darren New 
San Diego, CA, USA (PST). Cryptokeys on demand.
   The 90/10 rule of toothpaste: the last 10% of 
         the tube lasts as long as the first 90%.