Re: [boost] [fusion] unpack into constructor?

From: Tobias Schwinger (tschwinger_at_[hidden])
Date: 2007-06-15 17:08:38

Peter Dimov wrote:
> Tobias Schwinger wrote:
>> Peter Dimov wrote:
> 
> ...
> 
>>> Why is there a need to detect a default constructor?
>> (I probably snipped away too much context...)
>>
>> A generic function object that constructs an arbitrary type would have
>> to know (unless having variadic templates, or being able to define
>> operator() as a nonmember function template).
> 
> Umm. Why?

OK, in the bind case nullary operator() can just be omitted (if there 
are no parameters there's no point to use bind in the first place).

But for the Fusion sequence case that wrapper would have to be entirely 
generic (IOW allow nullary calls if there is an appropriate 
constructor), because the sequence can be empty.

Regards,
Tobias