I really don't get what you hope for. The 'raise' statement already exists
in Python. I don't need a different way to spell that. So does 'if'.
On Sat, Sep 11, 2021, 2:37 PM Juancarlo Añez <apal...@gmail.com> wrote:
> David,
>
> It seems I didn't state clearly enough my original statement, which is
> that software will *_always_ *fail, even because of faulty hardware
> components, or cosmic rays.
>
> For software to be resilient, it must assert it's expected state.
>
> But that doesn't have to be with the *assert* statement, perhaps less so
> when the Python tradition is that those go away with just a "-O".
>
> I won't vouch for an *"invariant"* statement, because that's probably too
> much to ask for.
>
> So I'll just use *"if"* to assert more invariants in the code I write.
>
> Cheers,
>
> On Sat, Sep 11, 2021 at 2:05 PM David Mertz, Ph.D. <david.me...@gmail.com>
> wrote:
>
>> On Sat, Sep 11, 2021 at 9:20 AM Juancarlo Añez <apal...@gmail.com> wrote:
>>
>>> I'm happy about dropping the DBC theme and rebooting to make *assert* easier
>>> to use so it gets used more.
>>>
>>
>> I agree with Steven, Marc-Andé, and others in seeing "using assertions
>> more" as an anti-goal.
>>
>> This isn't to say that a given program should have fewer—nor more—lines
>> that start with `assert`. Rather, assertions should be use to ASSERT
>> conditions that should NEVER be violated. They are NOT to check whether
>> user input is bad. Nor whether a disk is unreliable. Nor whether a
>> computation takes too long. Nor whether a value is outside of a useful
>> range. Nor any of the other things that regular exception handling is well
>> designed for.
>>
>> If for some reason you find yourself completely unable to write "if not
>> (condition_to_check): ..." for mysterious reasons, you could use assert
>> this way (but don't):
>>
>> >>> try:
>> ... assert 2+2==5, "Bad arithmetic"
>> ... except AssertionError:
>> ... print("Configuring stuff to log problem")
>> ... raise
>> ...
>> Configuring stuff to log problem
>> Traceback (most recent call last):
>> File "<ipython-input-3-2a9bdbc65744>", line 2, in <module>
>> assert 2+2 == 5, "Bad arithmetic"
>> AssertionError: Bad arithmetic
>>
>> But again, that's bad code for the same reason your proposal would be bad
>> code. Assertions have the entire purpose of being possible to disable, and
>> to express conditions a programmer believes are *necessarily true*.
>>
>>
>> --
>> Keeping medicines from the bloodstreams of the sick; food
>> from the bellies of the hungry; books from the hands of the
>> uneducated; technology from the underdeveloped; and putting
>> advocates of freedom in prisons. Intellectual property is
>> to the 21st century what the slave trade was to the 16th.
>>
>
>
> --
> Juancarlo *Añez*
>
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