fusion fold and transform passing refs for lvalues as per result_of protocol

[SVN r38039]
This commit is contained in:
Dan Marsden
2007-06-19 21:30:06 +00:00
parent 0e5cb04b99
commit 09a6da1f80
13 changed files with 157 additions and 40 deletions

View File

@ -9,6 +9,7 @@
#include <boost/type_traits/is_convertible.hpp>
#include <boost/mpl/if.hpp>
#include <boost/type_traits/remove_reference.hpp>
namespace boost { namespace fusion { namespace detail
{
@ -43,14 +44,15 @@ namespace boost { namespace fusion { namespace detail
replacer(T const& old_value, T const& new_value)
: old_value(old_value), new_value(new_value) {}
template<typename Params>
template<typename Sig>
struct result;
template <typename U1, typename U2>
struct result<replacer<U1>(U2)>
{
typedef typename remove_reference<U2>::type value;
typedef typename
mpl::if_<is_convertible<T, U2>, U2, U2 const&>::type
mpl::if_<is_convertible<T, value>, value, value const&>::type
type;
};

View File

@ -9,6 +9,7 @@
#include <boost/utility/enable_if.hpp>
#include <boost/mpl/if.hpp>
#include <boost/type_traits/remove_reference.hpp>
namespace boost { namespace fusion { namespace detail
{
@ -49,8 +50,9 @@ namespace boost { namespace fusion { namespace detail
template <typename F1, typename T1, typename U>
struct result<replacer_if<F1, T1>(U)>
{
typedef typename remove_reference<U>::type value;
typedef typename
mpl::if_<is_convertible<T, U>, U, U const&>::type
mpl::if_<is_convertible<T, value>, value, value const&>::type
type;
};