Re: Is strong typing worth the cost?

[dmjones <derek@NOSPAMknosof.co.uk>]

Jim,

>> Jim Rogers:  What are the parameters of cost?
>> 
>> Me:  Money.  Developers time (original development, subsequent
>> maintenance), lost business opportunities being late to market
>> (finding staff with necessary skills, additional lead time in
>> getting it 'more right').  Plus lots of other things.
> 
> Your answers on cost parameters are still a bit vague. "Money" is not
> a cost parameter. It is a system of paying for those parameters.

But developers time and lost business opportunities are the next level
down the chain.

> You are correct in seeing that lost business opportunities produce
> negative economic results for a company. It appears that you have an
> underlying assumption is that weak typing is a tool to avoid lost
> business opportunities. Where is the proof for that assumption?

Strong typing requires me to pay more attention to 100% of the
source I write.  By pay attention I mean I have to get it through
the compiler (the compiler will pick me up on type errors that I will
have to invest time in fixing).  Using a weakly typed language does
not require me to invest so much time up front.

Usage of my program, by customers, will not result in all
statements being executed.  Say 70-80% are not executed (I can dig up
some papers on this).

Knowing this my management has instituted an 'only test what the
initial customers are likely to use' policy (of course if they really
knew what they were doing they would have an 'only write what the
customer is likely to use' policy, but we are in a hurry to get things
out the door and once written any code is kept).

So I have saved time by only concentrating on a subset of the code.
Now the question is, what is the cost & benefits of weak/strong
typing on the code I do concentrate on?

A small group of people, starting from scratch, say under 100K SLOC,
working for 6 months.  I think weak typing could win.

More people, having to use existing code, longer time period, then
yes strong typing would win.  No proof on this (what bad habits I
have picked up by posting to this group ;-), just practical experience.

> * Maintenance

I would rather pay higher maintenance costs and be in business
than have lower maintenance costs if I were in business.

I know from experience that many successful companies build
some of their products from the most tangled mess of source code.

> * Warranty Costs (the costs arising from dealing with unhappy
> customers)
> * Legal Costs (patents as well as injured party litigation)

These are the only issues that might generate a change of management
attitude.

Jerrey Carter:
> I recall seeing, but can't now find, an article that put the worldwide
> cost of crackers exploiting security flaws at $10G for a recent year.

Unless the vendor of the software pays, these are not costs in
the sense being discussed here.