[Haskell-cafe] Re: howto tuple fold to do n-ary cross product?

1 Dec 2008

      On 11/30/08 12:49, Larry Evans wrote:
[snip]
...
You'll see Domains can be an mpl::vector of any
length. The cross_nproduct_view_test.cpp tests
with a 3 element Domains:
typedef
      mpl::vector
      < mpl::range_c
      , mpl::range_c
      , mpl::range_c
      >
    domains;
OOPS.  That's in another test driver.  The one
in the cross_nproduct_view_test.cpp has:

     typedef range_c seq0;
     typedef range_c seq1;
     typedef range_c seq2;
     typedef range_c seq3;
         typedef
       list
       < seq0
       , seq1
       , seq2
       , seq3
       >
     domains;

The range_c template instance:

http://www.boost.org/doc/libs/1_37_0/libs/mpl/doc/refmanual/range-c.html

produces a type sequence of length 2.
So mpl::list is a sequence of sequences
similar to haskell's [[a]] except that it's a sequence
of a sequences of types instead of a sequence of
sequences of values.
...
The cross_nproduct_view template  and test driver
are found in the cross_nproduct_view.zip file here:
http://preview.tinyurl.com/5ar9g4