Re: [boost] [fusion] More quanfusion

From: Andy Little (andy_at_[hidden])
Date: 2006-09-14 04:00:10

"David Abrahams" wrote
> Joel de Guzman  writes:
>
>> advance_iterator looks general enough.
>
> What *is* an advance_iterator?

FWIW:

 fusion::advance_iterator<
    Sequence,                      // the sequence to advance over
    Stride,                             // number of positions in underlying 
                                          //sequence to move on 'next'
    StridedPosition,            //  underlying sequence::position *
                                          //    Stride + Offset
    Offset                             // offset in underlying sequence units
>

The main use is to  return a column in a linear sequence representing a matrix.

Also consider  :

sequence seq;

advance_iterator<sequence,..> i1(seq);
advance_iterator<sequence,..> i2(seq);

iterator_range<i1_type,i2_type>  range(i1,i2);:

advance_iterator<range, ..>  j1(range);
advance_iterator<range, ..>  j2(range);

iterator_range<j1_type,j2_type> range_on_range (j1,j2);

etc ...

regards
Andy Little