-----Original Message----- From: Hicham Mouline [mailto:hicham@mouline.org] Sent: 18 February 2010 17:38 To: 'boost-users@lists.boost.org' Subject: fusion: work of 4 sequences at the same time

Hi,

I am trying to apply fusion::for_each on a sequence, but inside the unary functor applied to each element, I need to know the index of the element in question, because I need to extract elements with the same index from other sequences.

fusion::vector<...> fseq1; fusion::vector<...> fseq2; fusion::vector<...> fseq3; fusion::vector<...> fseq4;

fusion::for_each( fseq1, functor<...>(fseq2, fseq3, fseq4) );

template <typename Seq2, typename Seq3, typename Seq4) struct functor { /// ctor

template <typename T> void operator()( const T& t) const { /// find out index of t in fseq1, /// use elements from fseq2,3,4 at the same index } };

I could use boost::fusion::find to get an iterator and then get its index, but this doesn not look clean,

Any ideas,

Rds,

Ah! fusion::zip is my friend. fusion::for_each( fusion::zip(fseq1, fseq2, fseq3, fseq4), functor() ); Could u confirm though that I will be able to modify fseq1, even through the zipping? Rds,