Re: Is strong typing worth the cost?

["Marc A. Criley" <mcqada95@earthlink.net>]

dmjones wrote:
> 
> 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)
> ?

So far the only aspect of strong typing that's been mentioned here is
that of type and constraint checking, i.e., defensive use.  Don't forget
that strong typing is also an offensive aid, allowing programmers to
implicitly embed massive amounts of information within their software
that can then be extracted with the aid of attributes.

Think about it, what relevent information can you deduce about the
characteristics of:

   Alt : Integer;

versus:

   type Altitude_Type is range 0 .. 50_000;
   Alt : Altitude_Type;

?

E.g., 'First, 'Last, 'Range, etc.

The inherent ability to embed and extract information via properly
conceived type definition is one of the most overlooked and underused
strengths of strong typing.  Don't fight strong typing, USE it!

Marc A. Criley
Consultant
Quadrus Corporation
www.quadruscorp.com