Boost.Fusion

• Boost.Spiritに含まれ、Boost.TupleをFusion Sequenceとしてコンセプト化し、置きかえるもの
• MPL SequenceはFusion Sequenceの要件を満たす
• MPLは型を操作し、Fusionはオブジェクトを操作する
• 「fusion」とはコンパイルタイムとランタイムのプログラミングの「融合」という意味

[]#include[][] <boost/spirit/fusion/algorithm/for_each.hpp>[]

[]#include[][] <boost/mpl/for_each.hpp>[]
[]#include[][] <boost/mpl/vector_c.hpp>[]

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

[]#include[][] <boost/spirit/fusion/sequence/tuple.hpp>[]

[]#include[][] <boost/spirit/fusion/sequence/generate.hpp>[]

[]#include[][] <boost/xpressive/detail/fusion/sequence/cons.hpp>[]

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

[]#include[][] <iostream>[]
[]// See: libs/spirit/fusion/test/for_each_tests.cpp[]
[]namespace[] []pst[] {
  []namespace[] []fusion[] = []boost[]::[]fusion[];

  []namespace[] []mpl[] = []boost[]::[]mpl[];
  []// FunctionObject types[]

  []template[]< []class[] []Out[] >

  []struct[] []print[]

  {

    []Out[]& []out[];

    []explicit[] []print[]([]Out[]& []out_[]) : []out[]([]out_[]) { }
    []template[]< []class[] []T[] >

    []void[] []operator[]()([]T[] []const[]& []v[]) []const[] { []out[] << []L[][]"[ "[] << []v[] << []L[][]" ] "[]; }

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

  []print[]<[]Out[]> []make_print[]([]Out[]& []out_[]) { []return[] []print[]<[]Out[]>([]out_[]); }
  []struct[] []increment[]

  {

    []template[]< []class[] []T[] >

    []void[] []operator[]()([]T[]& []v[]) []const[] { ++[]v[]; }

  };
  []// helpers[]

  []template[]< []class[] []FusionSequence[] >

  []void[] []print_for_each[]([]FusionSequence[] []const[]& []seq[])

  {

    []fusion[]::[]for_each[]([]seq[], []make_print[]([]std[]::[]wcout[]));

    []std[]::[]wcout[] << []std[]::[]endl[];

  }
  []template[]< []class[] []FusionSequence[] >

  []void[] []increment_for_each[]([]FusionSequence[]& []seq[])

  {

    []fusion[]::[]for_each[]([]seq[], []increment[]());

  }
  []// main[]

  []void[] []test_main[]()

  {

    {

      []std[]::[]wcout[] << []L[][]"MPLSequence is also FusionSequence..."[] << []std[]::[]endl[];

      []typedef[] []mpl[]::[]vector_c[]<[]int[], 2, 3, 4, 5, 6> []mpl_seq_t[];

      []mpl_seq_t[] []ms[];

      []// IntegralConstant has an automatic conversion to[]

      []// a wrapped integral type(int, etc).[]

      []print_for_each[]([]ms[]);

      []// The conversion makes mpl::for_each work.[]

      []mpl[]::[]for_each[]<[]mpl_seq_t[]>([]make_print[]([]std[]::[]wcout[])); []std[]::[]wcout[] << []std[]::[]endl[];

    }
    {

      []std[]::[]wcout[] << []L[][]"Spirit has the tuple..."[] << []std[]::[]endl[];

      []typedef[] []fusion[]::[]tuple[]<[]int[], []wchar_t[], []double[], []wchar_t[] []const[]*> []tuple_t[];

      []tuple_t[] []t[](1, []L[][]'x'[], 3.3, []L[][]"Ruby"[]);

      []print_for_each[]([]t[]);

      []increment_for_each[]([]t[]); []print_for_each[]([]t[]);

    }
    { []// boost::tuple is *NOT* a FusionSequence.[]

      []typedef[] []boost[]::[]tuple[]<[]int[], []wchar_t[], []double[], []wchar_t[] []const[]*> []boost_tuple_t[];

      []boost_tuple_t[] []bt[](1, []L[][]'x'[], 3.3, []L[][]"Ruby"[]);

      []// print_for_each(bt); error![]

    }

    

    {

      []std[]::[]wcout[] << []L[][]"Xpressive has a simple FusionSequence, cons..."[] << []std[]::[]endl[];

      []typedef[] []fusion[]::[]cons[]<[]int[],

        []fusion[]::[]cons[]<[]wchar_t[],

          []fusion[]::[]cons[]<[]double[],

            []fusion[]::[]cons[]<[]wchar_t[] []const[][5]> > > > []cons_t[];

      []cons_t[] []c[] =

        []fusion[]::[]make_cons[](1,

          []fusion[]::[]make_cons[]([]L[][]'x'[],

            []fusion[]::[]make_cons[](3.3,

              []fusion[]::[]make_cons[]([]L[][]"Ruby"[]))));

      []print_for_each[]([]c[]);

    }
    {

      []std[]::[]wcout[] << []L[][]"This is the *FUSION*..."[] << []std[]::[]endl[];

      []typedef[] []mpl[]::[]vector[]<[]int[], []wchar_t[], []double[], []wchar_t[] []const[]*> []mpl_seq_t[];

      []typedef[] []fusion[]::[]meta[]::[]generate[]<[]mpl_seq_t[]>::[]type[] []tuple_t[];

      []tuple_t[] []t[](1, []L[][]'x'[], 3.3, []L[][]"Ruby"[]);

      []print_for_each[]([]t[]);

    }

  }

} []// namespace pst[]
[]int[] []main[]()

{

  []pst[]::[]test_main[]();

  []std[]::[]wcin[].[]ignore[](); []return[] 0;

}