続コンパイルタイム・ポリモーフィズム

C++ Grammar
  • id:y-hamigaki:20060407に関連して
  • 特に、Metafunctionのカスタマイズが必要ない場合、継承階層が働くように、デフォルトの動作(メンバ関数を呼び出す等)はない方が良いと思う
    • 例えば、の一番上のboost_range_beginは、ある基底クラスがRangeとしてカスタマイズされていても、その派生クラスを全て食べてしまう
  • クラス内部のtypedefによってカスタマイズの方法を指定してもらうのはどうだろう
    • enumerate自体はボツになるかも

[]namespace[] []pstade[][] { [][]namespace[] []tomato[][] {[]


[]class[] []enumerate_access[]

[]{[]

[]public[][]: [][]// ←friendの動作が怪しいのであきらめる[]

    []template[][]< [][]class[] []T[][], [][]class[] []Functor[][] > [][]static[]

    []Functor[] []detail_call[][]([][]T[][]& [][]x[][], [][]Functor[] []fun[][])[]

[]    {[]

        []return[] []x[][].[][]pstade_tomato_enumerate[][]([][]fun[][]);[]

[]    }[]

[]};[]



[]namespace[] []enumerate_detail[][] {[]



    []// BOOST_MPL_HAS_XXX_TRAIT_DEFはVC++で動かないので注意[]

    []// ...http://lists.boost.org/Archives/boost/2005/10/95809.php[]

    []PSTADE_HAS_XXX[][]([][]pstade_tomato_enumerable[][])[]



    []struct[] []member_function[]

[]    {[]

        []template[][]< [][]class[] []T[][], [][]class[] []Functor[][] > [][]static[]

        []Functor[] []call[][]([][]T[][]& [][]x[][], [][]Functor[] []fun[][])[]

[]        {[]

            []return[] []enumerate_access[][]::[][]detail_call[][]([][]x[][], [][]fun[][]);[]

[]        }[]

[]    };[]



    []struct[] []adl_customization[]

[]    {[]

        []template[][]< [][]class[] []T[][], [][]class[] []Functor[][] > [][]static[]

        []Functor[] []call[][]([][]T[][]& [][]x[][], [][]Functor[] []fun[][])[]

[]        {[]

            []return[] []pstade_tomato_enumerate[][]([][]x[][], [][]fun[][], [][]overload[][]());[]

[]        }[]

[]    };[]



    []struct[] []boost_range[]

[]    {[]

        []template[][]< [][]class[] []T[][], [][]class[] []Functor[][] > [][]static[]

        []Functor[] []call[][]([][]T[][]& [][]x[][], [][]Functor[] []fun[][])[]

[]        {[]

            []typedef[] []typename[] []boost[][]::[][]range_result_iterator[][]<[][]T[][]>::[][]type[] []iter_t[][];[]

            []typedef[] []typename[] []boost[][]::[][]iterator_reference[][]<[][]iter_t[][]>::[][]type[] []ref_t[][];[]
            []BOOST_FOREACH[][] ([][]ref_t[] []val[][], [][]x[][]) {[]

                []if[][] (![][]fun[][]([][]val[][]))[]

                    []return[] []fun[][];[]

[]            }[]
            []return[] []fun[][];[]

[]        }[]

[]    };[]



    []template[][]< [][]class[] []T[][], [][]class[] []Functor[][] > [][]inline[]

    []Functor[] []aux[][]([][]T[][]& [][]x[][], [][]Functor[] []fun[][])[]

[]    {[]

        []typedef[] []typename[]

        []boost[][]::[][]mpl[][]::[][]eval_if[][]< [][]has_pstade_tomato_enumerable[][]<[][]T[][]>,[]

            []boost[][]::[][]mpl[][]::[][]identity[][]<[][]member_function[][]>,[]

            []boost[][]::[][]mpl[][]::[][]if_[][]< [][]apple[][]::[][]is_boost_range[][]<[][]T[][]>, [][]// ←正確に判定することは不可能(あくまでサービス)[]

                []boost_range[][],[]

                []adl_customization[]

[]            >[]

[]        >::[][]type[] []impl_t[][];[]
        []return[] []impl_t[][]::[][]call[][]([][]x[][], [][]fun[][]);[]

[]    };[]



[]} [][]// namespace enumerate_detail[]



[]template[][]< [][]class[] []Enumerable[][], [][]class[] []Functor[][] > [][]inline[]

[]Functor[] []enumerate[][]([][]Enumerable[][]& [][]e[][], [][]Functor[] []fun[][])[]

[]{[]

    []return[] []enumerate_detail[][]::[][]aux[][]([][]e[][], [][]fun[][]);[]

[]};[]



[]template[][]< [][]class[] []Enumerable[][], [][]class[] []Functor[][] > [][]inline[]

[]Functor[] []enumerate[][]([][]const[] []Enumerable[][]& [][]e[][], [][]Functor[] []fun[][])[]

[]{[]

    []return[] []enumerate_detail[][]::[][]aux[][]([][]e[][], [][]fun[][]);[]

[]};[]



[]// ある実装の例[]

[]//[]
[]namespace[] []child_windows_detail[][] {[]



    []template[][]< [][]class[] []Functor[][] >[]

    []struct[] []data[]

[]    {[]

        []data[][]([][]Functor[] []fun[][]) :[]

            []m_fun[][]([][]fun[][]) []

[]        { }[]
        []Functor[] []m_fun[][];[]

[]    };[]



    []template[][]< [][]class[] []DataT[][] >[]

    []BOOL[] []CALLBACK[] []proc[][]([][]HWND[] []hWnd[][], [][]LPARAM[] []lParam[][])[]

[]    {[]

        []BOOST_ASSERT[][]([][]diet[][]::[][]valid[][]([][]hWnd[][]));[]
        []DataT[][] *[][]pdata[][] = [][]reinterpret_cast[][]<[][]DataT[][] *>([][]lParam[][]);[]

        []return[] []tomato[][]::[][]boolean[][]([][]pdata[][]->[][]m_fun[][]([][]hWnd[][]));[]

[]    }[]



    []template[][]< [][]class[] []Functor[][] >[]

    []Functor[] []enumerate[][]([][]HWND[] []hWndParent[][], [][]Functor[] []fun[][])[]

[]    {[]

        []typedef[] []data[][]<[][]Functor[][]> [][]data_t[][];[]

        []data_t[] []data[][]([][]fun[][]);[]
[]        ::[][]EnumChildWindows[][]([]

            []hWndParent[][],[]

[]            &[][]proc[][]<[][]data_t[][]>,[]

            []reinterpret_cast[][]<[][]LPARAM[][]>(&[][]data[][])[]

[]        );[]
        []return[] []data[][].[][]m_fun[][];[]

[]    }[]



[]} [][]// namespace child_windows_detail[]



[]struct[] []child_windows[]

[]{[]

    []// メンバ関数pstade_tomato_enumerateを使って[]

    []// カスタマイズすることの表明[]

    []typedef[] []child_windows[] []pstade_tomato_enumerable[][];[]
    []explicit[] []child_windows[][]([][]HWND[] []hWndParent[][]) :[]

        []m_hWndParent[][]([][]hWndParent[][])[]

[]    { }[]
[]private[][]:[]

    []HWND[] []m_hWndParent[][];[]
[]friend[] []class[] []enumerate_access[][];[]

    []template[][]< [][]class[] []Functor[][] >[]

    []Functor[] []pstade_tomato_enumerate[][]([][]Functor[] []fun[][]) [][]const[]

[]    {[]

        []// クラス内に実装をなるべく書かない(自分の)流行[]

        []return[] []child_windows_detail[][]::[][]enumerate[][]([][]m_hWndParent[][], [][]fun[][]);[]

[]    }[]

[]};[]



[]} } [][]// namespace pstade::tomato[]