Re: [boost] [preprocessor] Warning: Incoming

Subject: Re: [boost] [preprocessor] Warning: Incoming
From: Eric Niebler (eric_at_[hidden])
Date: 2011-07-01 11:34:35

On 6/30/2011 11:09 PM, Paul Mensonides wrote:
> This notion of a, b, c being a good way to store elements (which are 
> possibly empty sequences of preprocessing tokens and whitespace 
> separations) needs to die.  I was just watching some of the Boostcon 
> videos and in one of them (something like Haskell = C++ TMP) there are 
> examples that utilize variadic templates to pass around lists of types.  
> However, in the example, they are "open".  I.e. not bounded by something 
> that collects them as a singular entity.  I don't have it in front of me, 
> but something like:
> 
> template<class, class... T> struct count {
>     enum { value = 1 + count<T...>::value };
> };
> 
> template<> struct count<> {
>     enum { value = 0 };
> };
> 
> ...but this is terrible.  It doesn't take away from the point of the 
> talk, but it should be something like count<typelist<A, B, C>>, not 
> count<A, B, C>.

I'm not disagreeing, but I'd like to know why you believe this is true
for templates as well as macros.

-- 
Eric Niebler
BoostPro Computing
http://www.boostpro.com