Exception/Error division in D

[Dmitry Olshansky]

On 30.05.2012 19:05, Steven Schveighoffer wrote:
> On Wed, 30 May 2012 05:32:00 -0400, Don Clugston <dac at nospam.com> wrote:
>
>> On 30/05/12 10:40, Jonathan M Davis wrote:
>>> On Wednesday, May 30, 2012 10:26:36 deadalnix wrote:
>>>> The fact that error don't trigger scope and everything is nonsensial.
>>>
>>> If an Error is truly unrecoverable (as they're generally supposed to
>>> be), then
>>> what does it matter? Something fatal occured in your program, so it
>>> terminates. Because it's an Error, you can get a stack trace and report
>>> something before the program actually terminates, but continuing
>>> execution
>>> after an Error is considered to be truly _bad_ idea, so in general,
>>> why does
>>> it matter whether scope statements, finally blocks, or destructors get
>>> executed? It's only rarer cases where you're trying to do something like
>>> create a unit test framework on top of assert that you would need to
>>> catch an
>>> Error, and that's questionable enough as it is. In normal program
>>> execution,
>>> an error is fatal, so cleanup is irrelevant and even potentially
>>> dangerous,
>>> because your program is already in an invalid state.
>>
>> That's true for things like segfaults, but in the case of an
>> AssertError, there's no reason to believe that cleanup would cause any
>> damage.
>
> There's also no reason to assume that orderly cleanup *doesn't* cause
> any damage. In fact, it's not reasonable to assume *anything*.
>
> Which is the point. If you want to recover from an error, you have to do
> it manually. It should be doable, but the default handling should not
> need to be defined (i.e. implementations should be free to do whatever
> they want).
>
> But there is no reasonable *default* for handling an error that the
> runtime can assume.
>

I'd say that calling scope, destructors etc. on Error being thrown is 
the most _useful_ thing in all cases. If you realy-realy afraid of 
memory corruption killing sensitive data, taking control of OS and so on 
-  you just catch Errors early on inside such sensitive functions. And 
call C's abort(). And that's it.

Let's make common and hard case default and automatic plz.

-- 
Dmitry Olshansky