RE: Is strong typing worth the cost?

["Beard, Frank [Contractor]" <beardf@spawar.navy.mil>]

This will be very difficult to get an apples to apples
comparison, because the group that is not allowed to use
subranges or subtypes should also suppress range checking.
Because then they will have to program in all the necessary
checking to prevent erroneous results.  The group that uses
subtypes/subranges will mean they had to spend some time
in some up front analysis, where the unprotected group will
not.

The fun will begin when your test data contains out of
range values and the unprotected group starts producing
all type of erroneous results, which will take hours, or
days, if ever, to uncover, where the strongly type group
will find it in minutes.

Unless what you're really talking about is comparing the use
of parent types to subtypes.  In this case, you sort of in
the in-between realm.  You have range checking for when you
go outside the parent range, but then you still have to
manually code in the sub-range protection.

How are you going to determine that the unprotected group
programmed all the necessary checking?  Are you going to
have some type of code analysis software to check it out?
This will have a huge impact on downstream maintenance.

Frank

-----Original Message-----
From: dmjones [mailto:derek@NOSPAMknosof.co.uk]
Sent: Monday, April 29, 2002 2:38 PM
To: comp.lang.ada@ada.eu.org
Subject: Re: Is strong typing worth the cost?


Ted,
 
>> I have been trying to locate evidence that the cost of the use
>> of strong typing is repaid by a greater benefit.
> 
> There was a study done on compiler software by Rational. It showed
> something like 2x productivity for Ada over C, with the credit being
> laid at least partially on Ada's strong typing. It should be available
> somewhere on their website, but you'll probably have to search for it.

Thanks for the reference.  But I my interest is purely in
the advantages of strong typing.  Language comparison is too
broad an issue.

The experiment I had in mind was two set of subjects, all
working on the same Ada program.  However, one set of subjects
is not allowed to use subranges or subtypes. All objects
holding integer values have integer type.  The other
set of subjects would be able to create as many different
integer types as they liked.

How long would each group of subjects take to complete their
tasks, and what would down stream maintenance costs be (for
programs created by each set of subjects)
?
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