Re: Typing in Ada

["Robert I. Eachus" <rieachus@comcast.net>]

Niklas Holsti wrote:

> To return to Nick Robert's example, the numbers 100 and 200 should 
> either come from the requirements specification ("The program shall be 
> able to count  up to 100 apples and 200 oranges...") or should appear in 
> the software user manual ("The program can count up to 100 apples and 
> 200 oranges"). So then it is clear that the program satisfies its 
> requirements (or it won't compile) and satisfies its user manual, 
> whatever range Standard.Integer has on the current platform.

Amen! It would be nice if one tenth the energy that has gone into the 
thread started by a misunderstanding about whether Ada was being used in 
the 7E7 project went into evangelizing simple fundamental points like 
this.  Then no matter what programming language was used, the software 
would have a much better chance of being right.  It is not a selling 
point that Ada makes it easier to trace requirements, unless the person 
you are selling to understands why requirements traceability is important.

Yes, this is an advantage of Ada.  But before you can sell Ada, you need 
people to understand why requirements documents, software development 
plans and software user manuals are important living documents that need 
to be maintained interactively during software development.

Anyone who thinks that the requirements document shouldn't be changed 
during the software development stage hasn't worked on a real project. 
There are going to be some "boilerplate" pages in requirements document. 
  But outside of those, you should expect to add a page or more of 
footnotes to each page in the original requirements document.  These 
should note "derived" requirements which are a consequence of the 
implementation chosen, clarifications of requirements, and any really 
actual changes in requirements agreed to by all parties. I've called 
them footnotes, but only because the requirements document may also be a 
legal contract.

-- 

                                           Robert I. Eachus

"The terrorists rejoice in the killing of the innocent, and have 
promised similar violence against Americans, against all free peoples, 
and against any Muslims who reject their ideology of murder. Their 
barbarism cannot be appeased, and their hatred cannot be satisfied. 
There's only one way to deal with terror: We must confront the enemy and 
stay on the offensive until these killers are defeated." -- George W. Bush