Re: [boost] [gsoc-2013] Boost.Expected

Subject: Re: [boost] [gsoc-2013] Boost.Expected
From: Vicente J. Botet Escriba (vicente.botet_at_[hidden])
Date: 2013-04-24 17:29:51

Le 24/04/13 19:49, Gottlob Frege a écrit :
> On Wed, Apr 24, 2013 at 12:47 PM, Vicente J. Botet Escriba <
> vicente.botet_at_[hidden]> wrote:
>
>> Le 24/04/13 18:02, Gottlob Frege a écrit :
>>
>>   One thing I missed in this conversation:
>>> Are we considering the Alexandrescu behaviour of throwing in the
>>> destructor
>>> if the expected<> has not been read?
>>>
>> Why would you want to that?
>
> I didn't say I did, but some might.  And the Alexandrescu version (which
> was referenced as one design) works that way.
I didn't understood it this way. I've checked the slides and I have not 
found nothing about the destructor. Could you point me where have you 
found that the destructor throws if the value were not read?
>
>
>>
>>> I was imagining just an excepted<likely_type, error_type> class.  I forgot
>>> about the novel throwing behaviour.
>>>
>> This will correspond to expected_or_error.
>>
>>
> I'm hoping for just one class, not multiple.
>
>

I didn't catch that you were suggesting to have

template <typename T, typename ExceptionalType= std::exception_ptr>
class expected;

Humm, this could be done, but the has_exception function has no sense if 
the ExceptionalType is not exception_ptr.
But a get_exceptional and accept_exceptional_visitor have sense in both 
cases.

Best,
Vicente