Re: function Is_Open (File : File_Type) return Boolean; :Text_io

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Fri, 30 Oct 2015 20:07:18 +0100, G.B. wrote:

> On 30.10.15 17:20, Dmitry A. Kazakov wrote:
>> On Fri, 30 Oct 2015 15:32:16 +0100, G.B. wrote:
>>
>>> On 30.10.15 09:39, Dmitry A. Kazakov wrote:
>>>> The concern is safe design. If [program] B has bugs it cannot be
>>>> relied on to determine if it has them.
>>>
>>> Uhm, so what?  Which kind of program is relied upon to determine
>>> if it has bugs or not?
>>
>> A program that contains run-time checks for bugs.
> 
> I don't think anybody says that, nor does "contract based design",

Anybody but you?

>> Positive of *what*?
> 
> Positive of what we now have learned may (not) be the desired outcome.

Thus:

"Detecting a false positive needs to be assessed empirically."

reads as

"Somebody needs empirically assess misinterpretation of desired outcomes as
undesired outcomes..."

May I suggest, for a start, do not misinterpret anything, then you won't
need to assess that later... (:-))

>> You first need a workable (...) definition of a correct
>> program
> 
> What makes you assume that a specific, formalistic definition of
> a correct program is the workable one?

Easy. Any non-contradictory definition is workable.

> Except per the narrow situation-excluding circularity of
> "work" = "operation":

Workable here = logically consistent.

You seem are under a [false] impression that since ideal circles do not
exist the car wheels can be made square...

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de