Re: [boost] proto::or_ arity

From: Eric Niebler (eric_at_[hidden])
Date: 2007-04-18 14:06:13

Larry Evans wrote:
> On 04/17/2007 09:24 PM, Maurizio Vitale wrote:
>>>  (and maybe 0 arguments as
>>>
>>>> well).
>>>
<snip>
> 
> I've just encounted a need for something like this.  For example,
> if you have a list of types for which you want to apply the or_ to,
> however, that list must by calculated, then the only way to apply
> or to it is with a fold operation.  Since mpl::fold takes
> an argument represening the initial state, this would naturally
> be proto::or_<> in case you want to proto::or_ together a list
> of types.
<snip>

Interesting. In order for this to work, proto::or_ would need to be an 
extensible mpl sequence, right? It currently is not.

-- 
Eric Niebler
Boost Consulting
www.boost-consulting.com