Re: [boost] [mpl] bug: mpl::is_sequence< mpl::int_<1> > fails to compile

From: Tobias Schwinger (tschwinger_at_[hidden])
Date: 2006-05-07 16:12:07

David Abrahams wrote:
> Tobias Schwinger <tschwinger_at_[hidden]> writes:
> 
> 
>>For those about to reply "don't use is_sequence" please answer this
>>question first:
>>
>>How to traverse a tree where the nodes are sequences and the leafes
>>are mpl::intS without it?
> 
> 
> Just reformulate the tree so that nodes are all wrapped in something
> you can recognize reliably:
> 
>      tree<
>          list<
>              tree<vector<int, long> >
>            , tree<vector<long,int> >
>          >
>      >
> 

Pretty nice for hard-wired input -- impractical in my case, though. 
Why not make is_sequence work reliably? 

I understand the "concept detection hurts genericity" objection, but we shouldn't be too dogmatic about it -- that rule is not generic itself, after all. 

Regards,

Tobias