Re: [boost] feature request for optional

From: Fernando Cacciola (fernando_cacciola_at_[hidden])
Date: 2006-08-07 09:25:08

Sascha Krissler wrote:
> Fernando wrote:
>>> [...]
>>> But when i store values where the type has an
>>> inline NaT value (for example NULL pointers) i cannot and need not
>>> use optional.
>>
>> Can you explain why you cannot use optional<>?
>> I definitely see that you don't need it, but for the sake of
>> genericity I just wouldn't mind the fact that some types do have an
>> identifiable null value and use optional<> all along.
>
> Well i could use it but i do not want to.
> The space complexity is linear as i have to
> store it for every entry and a perfect hash could grow alot even for
> a small number of entries.
>
So your problem boils down to sizeof(optional<T>)=sizeof(T)+sizeof(bool)?

I'm not sure I like your proposal from a semantic POV, so it might help if 
you could give more detail that just "optional is bigger than I want".
Can you show me a _concrete_ example for the iniline NaT case? Along with an 
example of a non inline case?

TIA

Fernando Cacciola