Hi,
I need something like the following (somewhat contrived) example to
work with boost::fusion::transform on a boost::fusion::vector or
other vector types that have reference types.
Note that the following doesn't compile.
---------------------------
#include
#include
struct pass_through
{
template <typename SignatureT>
struct result;
template <typename T>
struct result
{
typedef T type;
};
template <typename T>
T operator () (T value) const
{
return value;
}
};
int main()
{
using namespace boost::fusion;
int i = 5;
vector v(i);
vector v2(transform(v, pass_through()));
return 0;
}
---------------------------
This code doesn't compile because in deref_impl for the transform_view
when this code
static type
call(Iterator const& i)
{
return i.f(*i.first);
}
calls the pass_through function object's operator (), the compiler
deduces T to be int instead of int&. Is there any way to make this
work with Boost.Fusion, e.g. by somehow additionally passing the
actual type stored in the vector to the function object in some way
instead of relying on the compiler to deduce it?
I was thinking of maybe using the binary version of transform and
passing in a range_c containing integral constants from 0 to and then using this in operator () to retrieve the actual
type from the vector by using mpl::at. Is there a better/simpler way?
Thanks,
Martin
