Boost.Spiritの例(calculator)をBoost.Xpressiveで書ける

• spirit::grammar<>のようなフレームワークを使わなくていい
• SemanticActionも使えるようだ

[]#include[][] "stdafx.h"[]
[]#include[][] <iostream>[]

[]#include[][] <string>[]

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

[]#include[][] <boost/xpressive/xpressive_static.hpp>[]
[]// See:[]

[]//  http://www.boost.org/libs/spirit/doc/semantic_actions.html[]

[]//  or http://boost.cppll.jp/HEAD/libs/spirit/doc/semantic_actions.html[]
[]namespace[] []pst[] {

  []using[] []namespace[] []std[];

  []using[] []namespace[] []boost[];

  []using[] []namespace[] []boost[]::[]xpressive[];
  []// semantic actions[]

  []struct[] []printer[] : []action[]<[]printer[]>

  {

    []wstring[] []str[];

    []printer[]([]wstring[] []const[]& []str_[]) : []str[]([]str_[]) { }
    []template[]< []class[] []BidiIter[] >

    []bool[] []operator[]()([]match_results[]<[]BidiIter[]> []const[]& []match[], []BidiIter[] []cur[])

    {

      []wcout[] << []str[] << []endl[];

      []return[] []true[];

    }

  };
  []struct[] []digit_printer[] : []action[]<[]digit_printer[]>

  {

    []template[]< []class[] []BidiIter[] >

    []bool[] []operator[]()([]match_results[]<[]BidiIter[]> []const[]& []match[], []BidiIter[] []cur[])

    {

      []wcout[] << []match[].[]str[](1) << []endl[]; []// print s1[]

      []return[] []true[];

    }

  };
  []template[]< []class[] []BidiIter[] > []inline[] 

  []basic_regex[]<[]BidiIter[]> []make_caluculator_BNF[]()

  {

    []basic_regex[]<[]BidiIter[]> []expression[], []moreterms[], []term[], []morefactors[], []factor[];
    []// grammar[]

    []expression[]

      = []by_ref[]([]term[]) >> []by_ref[]([]moreterms[])

      ;

    []moreterms[]

      = []L[][]'+'[]  >>  []by_ref[]([]term[])    [[]printer[]([]L[][]"ADD"[])]       >> []by_ref[]([]moreterms[]) 

      | []L[][]'-'[]  >>  []by_ref[]([]term[])    [[]printer[]([]L[][]"SUBTRACT"[])]  >> []by_ref[]([]moreterms[])

      | []epsilon[]

      ;

    []term[]

      = []by_ref[]([]factor[]) >> []by_ref[]([]morefactors[])

      ;

    []morefactors[]

      = []L[][]'*'[]  >>  []by_ref[]([]factor[])  [[]printer[]([]L[][]"MULTIPLY"[])]  >> []by_ref[]([]morefactors[])

      | []L[][]'/'[]  >>  []by_ref[]([]factor[])  [[]printer[]([]L[][]"DIVIDE"[])]    >> []by_ref[]([]morefactors[])

      | []epsilon[]

      ;

    []factor[]

      = ([]s1[]= []_d[])[[]digit_printer[]()] []// s1に保存することを明記[]

      | []L[][]'('[]  >>  []expression[]      >> []L[][]')'[]

      | []L[][]'+'[]  >>  []by_ref[]([]factor[])

      | []L[][]'-'[]  >>  []by_ref[]([]factor[])  [[]printer[]([]L[][]"NEGATE"[])]

      ;
    []return[] []expression[];

  }
  []template[]< []class[] []BidiIter[] > []inline[]

  []basic_regex[]<[]BidiIter[]> []make_caluculator_EBNF[]()

  {

    []basic_regex[]<[]BidiIter[]> []expression[], []term[], []factor[];
    []expression[]

      = []by_ref[]([]term[])

        >> *( []L[][]'+'[]  >> []by_ref[]([]term[])   [[]printer[]([]L[][]"ADD"[])]

            | []L[][]'-'[]  >> []by_ref[]([]term[])   [[]printer[]([]L[][]"SUBTRACT"[])]

            )

      ;

    []term[]

      = []by_ref[]([]factor[])

        >> *( []L[][]'*'[]  >> []by_ref[]([]factor[]) [[]printer[]([]L[][]"MULTIPLY"[])]

            | []L[][]'/'[]  >> []by_ref[]([]factor[]) [[]printer[]([]L[][]"DIVIDE"[])]

            )

      ;

    []factor[]

      = ([]s1[]= +[]_d[])[[]digit_printer[]()]

      | []L[][]'('[]  >>  []expression[]      >> []L[][]')'[]

      | []L[][]'+'[]  >>  []by_ref[]([]factor[])

      | []L[][]'-'[]  >>  []by_ref[]([]factor[])  [[]printer[]([]L[][]"NEGATE"[])]

      ;
    []return[] []expression[];

  }
  []struct[] []is_not_space[]

  { []// I forgot isspace[]

    []bool[] []operator[]()([]wchar_t[] []ch[]) { []return[] []regex_match[]([]wstring[](1,[]ch[]), ~[]_s[]); }

  };
  []inline[] []void[] []test[]() {

    []wstring[] []input[]([]L[][]"(-1 + 2) * (3 + -4)"[]);
    []typedef[] []filter_iterator[]<[]is_not_space[], []wstring[]::[]const_iterator[]> []filter_iter_t[];
    []if[] ( ![]regex_match[](

          []filter_iter_t[]([]input[].[]begin[](), []input[].[]end[]()),

          []filter_iter_t[]([]input[].[]end[](), []input[].[]end[]()),

          []make_caluculator_EBNF[]<[]filter_iter_t[]>()) )

    {

      []wcout[] << []L[][]"error!"[] << []endl[];

    }

  }

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

{

  []pst[]::[]test[]();

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

  []return[] 0;

}