Re: Ada in command / control systems

[russ lyttle <lyttlec@removegmail.com>]

On 3/9/19 3:59 AM, Dmitry A. Kazakov wrote:
> On 2019-03-09 09:16, Simon Wright wrote:
>> russ lyttle <lyttlec@removegmail.com> writes:
>>
>>> Which brings up a recurring debate. If there is a conflict between two
>>> diagrams, which takes precedence?
>>
>> Neither, in my view (as a purist): there's a contradiction which needs
>> to be resolved.
> 
> A more interesting question is how do you detect if there is any?
> 
> Usually things flow in one direction, from diagrams down to the code. 
> This is why people attempt to promote diagrams to requirements. Because 
> otherwise you have comebacks, like:
> 
> 1. Find all diagrams related to procedure Foo?
> 
> 2. If specification of parameters Foo change, what changes on the 
> diagram A45-34E?
> 
> Now, as a purist, you must say, OK, if something felt wrong in Foo, I 
> ditch all the code, modify diagrams I suspect responsible for the mess 
> and then write the code all new...
> 
Write some checks and repeat as needed.

I find diagrams very helpful, but only as a visualization aid. Not as a 
deliverable in the contract. And the last diagram is developed from the 
code.