Re: [boost] Re: mpl/loki

From: Joel de Guzman (djowel_at_[hidden])
Date: 2003-07-12 18:26:38

Aleksey Gurtovoy <agurtovoy_at_[hidden]> wrote:
> David Abrahams wrote:
>> Aleksey Gurtovoy <agurtovoy_at_[hidden]> writes:
>> 
>>> IMO we should just stop using 'void_' for internal purposes and give it
>>> up to users :).
>> 
>> I am still unsure about 'void_' being better than 'nil' or
>> 'null'....  Users already have a type, 'void', which means void.
> 
> ... in conventional run-time programs. Unfortunately, 'void' is not special
> for metaprograms, many of which have a need to routinely manipulate it along
> with all other built-in types. 'mpl::void_' addresses this issue.
> 
>> There's no correspondence between void_ and void the way there is
>> between bool_ and bool.
> 
> 'void_' in MPL plays a role very similar to a role of  'void' in the core
> language. So, conceptually, there is a correspondence. Personally, I
> appreciate the analogy, dislike 'null'/'nil'/etc. for the lack of such, and
> would like to keep the name.

I agree. I used to use nil_t but since I bumped into MPL's void_, I
wouldn't want to use nil_t anymore. void_ simply makes sense. My
dictionary defines void as: 1) The state of nonexistence 2) An empty 
area or space, and nul/null as: 1) Nothing 2) A quantity of no importance.
IMO, the definition of void reflects mpl::void_ a lot more.

-- 
Joel de Guzman
joel at boost-consulting.com
http://www.boost-consulting.com
http://spirit.sf.net