Re: 4GL code in a deliverable (was: ARIANE-5 Failure)

[Ken Garlington <garlingtonke@lmtas.lmco.com>]

Arthur Evans Jr wrote:
> 
> There is (supposed to be) a clear trail from design to final code, and
> _all_ _tools_ _that_ _participate_ _in_ _that_ _trail_ are delivered
> with the product for use by the maintainers.

This would also imply that Ada code cannot be reused, without having access
to all of the tools and databases used to create the code and associated 
documentation. Do you really believe this?

Certainly, a Government agency can require that the software engineering
environment, databases, and documentation, be delivered with a
software application, particularly if the Government agency intends to
maintain the code. To suggest that this is a consequence of current Ada
policy is, to my thinking, more than a little bizarre. Ada source code can be
delivered without the tools/databases (e.g. MatrixX) used to develop it,
just as non-Ada source code may have to be delivered with such support. This
decision should be based on the expected maintenance strategy. Similarly,
the decision to use Ada may be influenced by the expected maintenance strategy. 
However, this doesn't mean that the deliverables are based on Ada policy!

> It seems fair to assume that there is a clear trail from design, through
> system equations, through MatrixX code (or whatever we call it), to Ada,
> to the final product.  My question, then, is this: Are both the source
> code for the 4GL and the 4GL product itself delivered?

MatrixX does not have textual "source code" per se. It has a database of
information which is represented graphically. In some respects, it is similar
to tools such as Teamwork or Statemate (although MatrixX is designed for a
specific domain).

>   - The 4GL source is not delivered.  In that case the maintainer has no
>     recourse in modifying the code except to do so in Ada.  I think
>     we'll all agree that this code is essentially unmaintainable

I think I'll disagree, having seen several examples of source code generated
by auto-generation systems and later maintained manually with success.

>   - The 4GL code is delivered.  But in that case the contractor is
>     admitting (the truth) that the algorithm was expressed in this
>     notation (that is, programmed in it), even though no waiver was
>     obtained permitting use of other than Ada.

Would this "truth" also exist if the device used to generate the Ada code
from the database was a human being, rather than a machine? It seems to
me the consequence of this interpretation of Ada policy is that all requirements
and design artifacts must be generated without the use of tools, else an
Ada waiver is required!

Fortunately, Ada waiver policy is interpreted more rationally, at least by
my customer...

-- 
LMTAS - "Our Brand Means Quality"