さよなら関数

C++ Boost.Sequence
  • Boost.Sequenceを少し覗いてみましたが、ショッキングなことになっている
  • 汎用関数においては生の関数がdeprecatedになるのかもしれない
    • 関数に見えるものが実は関数オブジェクト
    • Forwarding問題を解決するクラスを利用できる(実装はそのクラスから呼んでもらう)
    • 古いコンパイラの呼び出しのあいまいさも局所化できる
  • iteratorから直接値を取り出すのではなくなるらしい
    • const_iteratorはなくなるようだ
  • 以下、Boost.Sequenceのポリモーフィズムの概要
    • template template parameterのないコンパイラにも対応できる(detail::functionをMetafunctionClassを取るように変える)

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

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

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




[]namespace[] []pstade[][] {[]
    []namespace[] []customization[][] {[]
        []template[][]< [][]class[] []Range[][] >[]

        []struct[] []tag[][];[]
        []template[][]< [][]class[] []Range[][], [][]class[] []Tag[][] = [][]typename[] []tag[][]<[][]Range[][]>::[][]type[][] >[]

        []struct[] []operations[][];[]
[]    } [][]// namespace customization[]
    []namespace[] []detail[][] {[]
        []template[][]< [][]class[] []Range[][] >[]

        []struct[] []operations[][] :[]

            []customization[][]::[][]operations[][]<[]

                []typename[] []boost[][]::[][]remove_cv[][]<[][]Range[][]>::[][]type[]

[]            >[]

[]        { };[]
[]    } [][]// namespace detail[]
    []namespace[] []meta[][] {[]
        []template[][]< [][]class[] []Range[][] >[]

        []struct[] []begin[][] : [][]detail[][]::[][]operations[][]<[][]Range[][]>::[][]begin[][] { };[]
        []template[][]< [][]class[] []Range[][] >[]

        []struct[] []end[][] : [][]detail[][]::[][]operations[][]<[][]Range[][]>::[][]end[][] { };[]
[]    } [][]// namespace meta[]
    []namespace[] []detail[][] {[]
        []template[][]< [][]template[][]< [][]class[][] > [][]class[] []F[][] >[]

        []struct[] []function[]

[]        {[]

            []template[][]< [][]class[] []X0[][] >[]

            []typename[] []F[][]<[][]const[] []X0[][]>::[][]type[]

            []operator[][]()([][]const[] []X0[][]& [][]a0[][]) [][]const[]

[]            {[]

                []return[] []F[][]<[][]const[] []X0[][]>()([][]a0[][]);[]

[]            }[]
            []template[][]< [][]class[] []X0[][] >[]

            []typename[] []F[][]<[][]X0[][]>::[][]type[]

            []operator[][]()([][]X0[][]& [][]a0[][]) [][]const[]

[]            {[]

                []return[] []F[][]<[][]X0[][]>()([][]a0[][]);[]

[]            }[]

[]        };[]
[]    } [][]// namespace detail[]
    []namespace[][] {[]

        []// ODRが怪しい[]

        []const[] []detail[][]::[][]function[][]<[][]meta[][]::[][]begin[][]> [][]begin[][] = { };[]

        []const[] []detail[][]::[][]function[][]<[][]meta[][]::[][]end[][]> [][]end[][] = { };[]

[]    }[]
[]} [][]// namespace pstade[]



[]#include[] []<vector>[]
[]struct[] []vector_tag[][] { };[]
[]namespace[] []pstade[][] { [][]namespace[] []customization[][] {[]
    []template[][]< [][]class[] []ValueT[][] >[]

    []struct[] []tag[][]< [][]std[][]::[][]vector[][]<[][]ValueT[][]> >[]

[]    {[]

        []typedef[][] ::[][]vector_tag[] []type[][];[]

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

    []struct[] []operations[][]< [][]VectorT[][], ::[][]vector_tag[][] >[]

[]    {[]

        []struct[] []begin[]

[]        {[]

            []typedef[] []typename[] []VectorT[][]::[][]iterator[] []type[][];[]
            []type[] []operator[][]()([][]VectorT[][]& [][]vec[][]) [][]const[]

[]            {[]

                []return[] []vec[][].[][]begin[][]();[]

[]            }[]

[]        };[]
        []struct[] []end[]

[]        {[]

            []typedef[] []typename[] []VectorT[][]::[][]iterator[] []type[][];[]
            []type[] []operator[][]()([][]VectorT[][]& [][]vec[][]) [][]const[]

[]            {[]

                []return[] []vec[][].[][]end[][]();[]

[]            }[]

[]        };[]

[]    };[]
[]} } [][]// namespace pstade::customization[]
[]#include[] []<iostream>[]
[]void[] []polym_test[][]()[]

[]{[]

    []using[] []namespace[] []pstade[][];[]
    []std[][]::[][]vector[][]<[][]int[][]> [][]vec[][]; {[]

        []vec[][].[][]push_back[][]([][]1[][]), [][]vec[][].[][]push_back[][]([][]2[][]), [][]vec[][].[][]push_back[][]([][]3[][]);[]

[]    }[]
    []typedef[] []meta[][]::[][]begin[][]< [][]std[][]::[][]vector[][]<[][]int[][]> >::[][]type[] []iter_t[][];[]

    []for[][] ([][]iter_t[] []it[][] = [][]begin[][]([][]vec[][]), [][]last[][] = [][]end[][]([][]vec[][]); [][]it[][] != [][]last[][]; ++[][]it[][]) {[]

        []std[][]::[][]cout[][] << *[][]it[][] << [][]std[][]::[][]endl[][];[]

[]    }[]

[]}[]