Re: Design By Contract

[dewar@merv.cs.nyu.edu (Robert Dewar)]

Don says

<<  - Simplicity which enables developers to focus on designing rather than
    trying to remember language rules. A simplistic macroscopic comparison
    of Eiffel and Ada based on the number of validity rules suggests that
    Eiffel is about 50 times simpler than Ada.>>


Simplicity is a very slippery term, what do you mean:

Simplicity of the description
Simplicity of format definition
Simplicity of programming applications
Simplicity of implementation

These are nowhere *near* the same thing. For example, let's compare the
floating-point rules in C and Ada. Gosh, C is FAR simpler, look at all
those rules in annex G in Ada, not to mention the basic stuff in chapter
3. None of that nonsense in C, C is much simpler.

But suppose the task is: write portable numerical codes. Oops, now we are
in big trouble in C, and the task is far *more* complex, because now we
have no guarantees from the language, and either the task is impossible,
or involves all kinds of complex external configuration control.

It is helpful whenever you use the word simple or complex to say exactly
what domain you are talking about. I see all the time people playing the
game where they argue simplicitly in one of these domains, implicitly
appealing to people's agreement that simplicity in another domain is crucial.