detail::functionN

C++ Boost.ResultOf
  • Boost.Accumulatorsに、もうdetail::functionNが含まれていた
  • これは、Forwarding Problemを解決するためのクラステンプレートである
  • boost::result_ofのサポートも勝手にやってくれる
  • これを使ったのモダンな実装がにある



[]#include[] []<boost/detail/function2.hpp>[]

[]#include[] []<boost/type_traits/is_same.hpp>[]

[]#include[] []<boost/utility/result_of.hpp>[]

[]#include[] []<boost/mpl/assert.hpp>[]

[]#include[] []<boost/mpl/placeholders.hpp>[]




[]template[][]<[][]class[] []X[][], [][]class[] []Y[][]>[]

[]struct[] []foo_base[]

[]{[]

    []typedef[] []X[][]& [][]result_type[][];[]
    []result_type[] []operator[][]()([][]X[][]& [][]x[][], [][]Y[][]&) [][]const[]

[]    {[]

        []return[] []x[][];[]

[]    }[]

[]};[]
[]template[][]<[][]class[] []Y[][]>[]

[]struct[] []foo_base[][]<[][]std[][]::[][]string[][], [][]Y[][]>[]

[]{[]

    []typedef[] []std[][]::[][]string[][]& [][]result_type[][];[]
    []result_type[] []operator[][]()([][]std[][]::[][]string[][]& [][]str[][], [][]Y[][]&) [][]const[]

[]    {[]

        []return[] []str[][];[]

[]    }[]

[]};[]



[]#if[][] BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1400))[]

    []struct[] []op_foo[][] :[]

        []boost[][]::[][]detail[][]::[][]function2[][]< [][]foo_base[][]<[][]boost[][]::[][]mpl[][]::[][]_[][], [][]boost[][]::[][]mpl[][]::[][]_[][]> >[]

[]    { };[]

[]#else[]

    []typedef[]

        []boost[][]::[][]detail[][]::[][]function2[][]< [][]foo_base[][]<[][]boost[][]::[][]mpl[][]::[][]_[][], [][]boost[][]::[][]mpl[][]::[][]_[][]> >[]

    []op_foo[][];[]

[]#endif[]



[]BOOST_MPL_ASSERT[][](( [][]boost[][]::[][]is_same[][]<[][]int[][]&, [][]boost[][]::[][]result_of[][]<[][]op_foo[][]([][]int[][]&, [][]int[][])>::[][]type[][]> ));[]

[]BOOST_MPL_ASSERT[][](( [][]boost[][]::[][]is_same[][]<[][]int[] []const[][]&, [][]boost[][]::[][]result_of[][]<[][]op_foo[][]([][]int[] []const[][]&, [][]int[][])>::[][]type[][]> ));[]

[]BOOST_MPL_ASSERT[][](( [][]boost[][]::[][]is_same[][]<[][]int[] []const[][]&, [][]boost[][]::[][]result_of[][]<[][]op_foo[][]([][]int[][], [][]int[][])>::[][]type[][]> )); [][]// rvalue[]
[]BOOST_MPL_ASSERT[][](( [][]boost[][]::[][]is_same[][]<[][]std[][]::[][]string[][]&, [][]boost[][]::[][]result_of[][]<[][]op_foo[][]([][]std[][]::[][]string[][]&, [][]int[][])>::[][]type[][]> ));[]



[]void[] []test[][]()[]

[]{[]

    []int[] []x[][] = [][]10[][];[]

    []int[] []y[][] = [][]5[][];[]

    []BOOST_CHECK[][]( [][]op_foo[][]()([][]x[][], [][]y[][]) == [][]10[][] );[]

[]}[]