Re: Is strong typing worth the cost?

["Marin David Condic" <dont.bother.mcondic.auntie.spam@[acm.org>]

First off, I can convince myself of the benefit of strong typing and don't
really need scientific proof that it is a better way to do business, so I'm
not opposed to Preben's example. (Or numerous other possible examples.) I
state that because now I'm going to play devil's advocate. :-)

The example shown was, of necessity, a very simple case that will *not*
illustrate the cost of doing the design needed to properly build a set of
types and subtypes for a system of realistic size. If you're approaching a
system of some magnitude and plan on utilizing strong typing to the fullest
desirable extent, then you've really got to do a lot of analysis and design
to actually exploit it. If you *don't* want to use strong typing, then
you've just eliminated a bunch of design work - which obviously costs less
up front. In fact, you can totally eliminate *any* design and just start
coding and save all the cost of analysis and design. ("O.K. You guys get
started writing the code while I go talk to the customer and find out what
they want..." :-)

In general, we convince ourselves that for larger systems, failure to do any
up front design costs a lot at the back end in terms of missed requirements,
debugging, rework, total failure, etc. I'm not sure that there is any
"scientific" evidence we can point to, but certainly a lot of experience
that tells us this ought to be "Conventional Wisdom". Properly using strong
typing (beyond the inherent checks within the language supplied types) is
something that requires you think about the problem, analyze the constraints
on everything, devise a set of types and operations that reflect the problem
space, etc., etc., etc. Most of us with experience doing this will contend
that, yes, it costs something up front but it saves a lot at the back end.
(Maybe the biggest benefit comes from the fact that you had to *think* about
the problem pretty rigorusly?) But its not totally unfair to ask if there is
anything that might demonstrate this with hard data rather than just
perceptions and anecdotes. How much evidence one might demand before
concluding that it is a wise thing to do is up to the individual.

MDC
--
Marin David Condic
Senior Software Engineer
Pace Micro Technology Americas    www.pacemicro.com
Enabling the digital revolution
e-Mail:    marin.condic@pacemicro.com


"Pascal Obry" <p.obry@wanadoo.fr> wrote in message
news:uwuuouuwi.fsf@wanadoo.fr...
>
> This is always hard to prove... But look at Preben example, the second
version
> of the program is no more complex than the first one. Both are so similar
than
> they certainly cost the same at the development step. But the second will
> catch the error and will avoid a debug session which cost more than
writing
> the piece of code in the example ! As you say we all have lot of example
like
> this... This is no proof, we don't have resources to play the game of
writing
> a software in two different languages and compare the results...
>