Re: [Boost-users] [mpl] Help with simple algorithm needed

From: Stephan Tolksdorf (andorxor_at_[hidden])
Date: 2006-07-15 05:20:00

OK, part of the problem is that mpl only supports vectors and lists of 
maximum size 20 by default. I guess vectors with several thousands of 
elements are beyond the realms of MPL code.

Stephan

Stephan Tolksdorf wrote:
> Hi
> 
> I'm trying to build a mpl::vector which looks like
> 
> [(a,1),(a,2),...,(a,a),(a+1,1),...,(b,b)],
> 
> where a < b are int's and (x,y) stands for mpl::pair< int_<x>, int_<y> >.
> 
> The following code does not compile with MSVC 8. Could somebody tell me 
> what's wrong with my code? Does someone have an idea how to solve this 
> problem more elegantly with MPL? Any help is much appreciated.
> 
> Code snippet with the vector named "ListofNMPairs":
> 
> template <typename N>
> struct NPush :
>      mpl::lambda<
>          mpl::push_front<
>              mpl::_1,
>              mpl::pair<N,  mpl::_2>
>          >
>      >::type
> { };
> 
> template <typename S>
> struct MyRange :
>          mpl::reverse_fold<
>              mpl::range_c<int, 1, S::value + 1>,
>              mpl::vector< >,
>              NPush<S>
>          >::type
> { };
> 
> typedef mpl::reverse_fold<
>      mpl::range_c<int, 16, 66>, // a=16, b=65
>      mpl::vector< >,
>      mpl::insert_range<
>          mpl::_1,
>          mpl::begin<mpl::_1>,
>          MyRange<mpl::_2>
>      >
>  >::type  ListofNMPairs;
> 
> Regards,
>    Stephan