Re: [boost] [xpressive] How can I get nested match_results?

From: Dave Jenkins (david_at_[hidden])
Date: 2008-05-21 12:02:11

You could use regex_id() to get the correct nested match_results. For 
example, to output the year:

std::cout << item(rTime.regex_id())[year] << '\n';

Regards,
Dave Jenkins

"shiwei xu" <xushiweizh_at_[hidden]> wrote in message 
news:c01ea5030805201216h1a4a39a9xd35397b30d7e2a08_at_mail.gmail.com...
> My program is the following.
> And my question is:
>
> I can get match_result such as item[time], item[count]. But, how can I get
> nested match_results, eg. item[time][year], item[time][month]?
>
>
> Best Regards,
>
> ShiWei Xu
>
> ----
>
> #include <iostream>
> #include <boost/xpressive/xpressive.hpp>
>
> using namespace boost::xpressive;
>
> typedef std::string::const_iterator iterator_;
> typedef basic_regex<iterator_> regex_;
> typedef regex_iterator<iterator_> regex_iterator_;
> typedef regex_iterator_::value_type match_results_;
> typedef match_results_::value_type sub_match_;
>
> boost::proto::terminal<char>::type const _dot = {'.'};
> boost::proto::terminal<char>::type const _gt = {'>'};
> boost::proto::terminal<char>::type const _quot = {'\"'};
>
> inline void example()
> {
>    std::string str = "<tr><td>2008-05-20</td><td>70</td></tr>";
>
>    // define some custom mark_tags with names more meaningful than s1, s2,
> etc.
>    mark_tag day(1), month(2), year(3), delim(4);
>
>    regex_ rTime = // DateTime value
>        (year = repeat<4>(_d)) >>        // year
>        (delim = (set='/','-')) >>        // followed by a delimiter ...
>        (month = repeat<1,2>(_d)) >> delim >>    // month
>        (day = repeat<1,2>(_d))            // day
>        ;
>
>    regex_ rInteger = +_d; // Integer value
>
>    regex_ rHtmlProperties =
>        +(+_w >> *_s >> '=' >> *_s >> _quot >> *~_quot >> _quot >> *_s);
>
>    mark_tag time(1), count(2);
>    regex_ rTrade =
>        (("<tr" >> +_s >> rHtmlProperties >> _gt) | "<tr>") >> *_s >>
>        "<td>" >> (time = rTime) >> "</td>" >> *_s >>
>        "<td>" >> (count = rInteger) >> "</td>" >> *_s >>
>        "</tr>"
>        ;
>
>    iterator_ first = str.begin();
>    iterator_ last = str.end();
>
>    regex_iterator_ cur(first, last, rTrade);
>    regex_iterator_ end;
>
>    for( ; cur != end; ++cur )
>    {
>        match_results_ item = *cur;
>        sub_match_ matched = item[0];
>        std::cout << matched << '\n';
>        std::cout << item[time] << ' ' << item[count] << '\n';
>    }
> }
>
> ///////////////////////////////////////////////////////////////////////////////
> // main
>
> int main()
> {
>    example();
>    return 0;
> }
>
> ///////////////////////////////////////////////////////////////////////////////
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