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

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[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
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42
test/algorithm/fold.cpp
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@ -19,6 +19,10 @@
#include <boost/mpl/int.hpp>
#include <boost/mpl/vector.hpp>
#include <boost/type_traits/remove_const.hpp>
#include <boost/type_traits/remove_reference.hpp>
#include <boost/type_traits/is_reference.hpp>
#include <string>
using boost::mpl::if_;
@ -33,7 +37,8 @@ struct add_ints_only
template <typename T, typename State>
struct result<add_ints_only(T,State)>
{
typedef State type;
typedef typename boost::remove_const<
typename boost::remove_reference<State>::type>::type type;
};
template <typename T, typename State>
@ -58,11 +63,16 @@ struct count_ints
template <typename T, typename CountT>
struct result<count_ints(T,CountT)>
{
typedef typename boost::remove_const<
typename boost::remove_reference<T>::type>::type elem;
typedef typename boost::remove_const<
typename boost::remove_reference<CountT>::type>::type state;
typedef typename
if_<
is_same<T, int>
, typename boost::mpl::next<CountT>::type
, CountT
is_same<elem, int>
, typename boost::mpl::next<state>::type
, state
>::type
type;
};
@ -86,6 +96,25 @@ struct appender
}
};
struct lvalue_adder
{
template<typename Sig>
struct result;
template<typename T0, typename T1>
struct result<lvalue_adder(T0&, T1)>
{
// Second argument still needs to support rvalues - see definition of fusion::fold
typedef T0 type;
};
template<typename T0, typename T1>
T0 operator()(T0& lhs, T1 const& rhs) const
{
return lhs + rhs;
}
};
int
main()
{
@ -130,6 +159,11 @@ main()
== "abcde");
}
{
vector<int, int> vec(1,2);
BOOST_TEST(fusion::fold(vec, 0, lvalue_adder()) == 3);
}
{
typedef vector<int, char, int, double> vector_type;
vector_type v(12345, 'x', 678910, 3.36);