Re: [boost] [Fusion] Heads up

From: Joel de Guzman (joel_at_[hidden])
Date: 2006-08-31 19:18:30

David Abrahams wrote:
> Joel de Guzman <joel_at_[hidden]> writes:
> 
>> There's also an interesting
>> use-case that became apparent recently: making arbitrary structs/classes
>> conforming sequences easily-- as easy as providing a single function.
>> Pardon me if this is rather sketchy at this point, but imagine
>> being able to write:
>>
>> Our user defined struct:
>>
>>      struct point { float x, float y; };
>>
>> Customization:
>>
>>      fusion::map<keys::x_, keys::y_, float&, float&>
>>      as_fusion_sequence(point& p)
>>      {
>>          return fusion::map_tie<keys::x_, keys::y_>(p.x, p.y);
>>      }
>>
>> Use:
>>
>>      point p = { 123.456, 789.012 };
>>      fusion::for_each(p, std::cout << _1 << std::endl);
> 
> That's nice, but I don't think it's really the same thing.  Doesn't it
> incur an extra level of indirection?

Not the same as what? Sorry, I think I missed something in
your question/comment.

Cheers,
-- 
Joel de Guzman
http://www.boost-consulting.com
http://spirit.sf.net