Re: [boost] New Library Proposal: dual_state

From: Fernando Cacciola (fernando_cacciola_at_[hidden])
Date: 2005-07-11 12:16:32

"David Abrahams" <dave_at_[hidden]> escribió en el mensaje 
news:uoe9abw3k.fsf_at_boost-consulting.com...
> "Jost, Andrew" <Andrew_Jost_at_[hidden]> writes:
>
>>>From: boost-bounces_at_[hidden]
>> [mailto:boost-bounces_at_[hidden]] On Behalf Of Eelis van der Weegen
>>
>>>Jost, Andrew wrote:
>>>> I am curious if there is support for what I'm calling a "dual_state"
>>>> template class.
>>> From your description it sounds a lot like Boost.Optional. What are
>> the main differences?
>>>Eelis
>>
>> I'll admit I did not even pause at Boost.optional when I scanned the
>> library listing for previous work, a failure in my ability to connect
>> the description, "Discriminated-union wrapper for optional values," with
>> the concept I had in mind.
>
> Oh, you're right!  That is a terrible one-line description, because
>
>  a. It uses technical terms that many people probably don't know
>     "discriminated union"
>
>  b. optional doesn't really act like a union (in any way that matches
>     my intuition)!  I understand the theoretical connection, of
>     course, but nobody is thinking that way when they read brief
>     descriptions.
>
Very good point.
Right now I can think of

"A library to wrap and manipulate values can be be 'optional': that is, 
(explicitely) uninitialized"

but that doesn't sound very inspired.

Any proposals?

Fernando Cacciola
SciSoft