Re: {Pre,Post}conditions and side effects

["Randy Brukardt" <randy@rrsoftware.com>]

"Niklas Holsti" <niklas.holsti@tidorum.invalid> wrote in message 
news:cr1snsF60hoU1@mid.individual.net...
> On 15-05-07 22:01 , Randy Brukardt wrote:
>> <Stefan.Lucks@uni-weimar.de> wrote in message
>> news:alpine.DEB.2.11.1505071909280.16448@debian...
>> ...
>>> One property of a proper precondition (or postcondition or ...) is that
>>> disabling the check does not change the functional behaviour of correct
>>> programs.
>>
>> Sure, but this is irrelevant. There are no "correct" programs (in all
>> possible senses). How do you know that you have a correct program? If you
>> use some prover program, it too may have bugs. Or there might be bad data
>> (cosmic rays?)
>
> Those are practical problems, not problems of principle. If you would take 
> the same attitude to mathematics, you would claim that there are no 
> correct theorems. So I disagree with you.

All programming is practical. We do not care about theorems, only that the 
current program is correct in the current environment. Everything has to be 
reproved when anything changes (another good reason for putting it into the 
compiler, as skipping the step isn't possible, and thus problems like the 
Ariene 5 don't happen).

It seems that most of you here are infected with the "theory" disease. I 
want to make practical programming better, and I don't give a damn about any 
stupid theories. Maybe I'm just getting crazy in my late middle age. :-)

                                                  Randy.