On 09/03/2007 07:46 PM, Andreas Klöckner wrote:
Hi all,
I came up with the following implementation of a "flatten" operation
that turns a sequence of sequences into a flat list:
[...]
It compiles (using gcc 4.2.1), but prints 0 instead of the expected
7. What am I doing wrong?
I'm not sure of what you might be doing wrong, but if you take away the
lambda expression, and use another level of indirection things work for
me:
----- cut ------
#include <iostream>
#include
#include
#include
#include
#include
#include
#include
#include
// joins two sequences
struct join
{
template
struct apply
{
typedef typename boost::mpl::copy<
Seq2,
boost::mpl::back_inserter<Seq1>
>::type type;
};
};
template<class Sequence>
struct flatten
{
typedef typename boost::mpl::fold<
Sequence,
typename boost::mpl::clear<Sequence>::type,
join
>::type type;
};
typedef
flatten<
boost::mpl::vector<
boost::mpl::vector_c,
boost::mpl::vector_c
>
>::type
flatvec;
int main()
{
std::cout << boost::mpl::size<flatvec>::value << std::endl;
}
----- cut ------
I hope it helps... Did you manage to fix this some other way?
Cheers,
Tiago
--
Tiago de Paula Peixoto
