Boost.spiritセグメンテーションフォールトの.fntファイル用のパーサーを書くしようとする複合文法で

Question

を解析：

int main() 
{ 
    const auto word = qi::lexeme [ + qi::alnum ]; 
    const auto literal = qi::lexeme[ '"' >> + (qi::char_ - '"') >> '"' ]; 
    const auto value = literal | qi::double_; 
    const auto pair = word >> '=' >> value; 
    const auto line = word >> (+ pair) >> qi::eol; 
    const auto document = + line; 

    std::ifstream in("input.fnt"); 
    in.unsetf(std::ios::skipws); 
    boost::spirit::istream_iterator begin(in); 
    boost::spirit::istream_iterator end; 

    qi::parse(begin, end, document); 
} 

実行がブースト::精神のディープス内セグメンテーションフォールトエラーで失敗します。しかし、文法を中間の文法（ルール）で構成しないように変更すると、成功します。 Internal Boost::Spirit code segfaults when parsing a composite grammarで

式テンプレートが一時への内部参照を保持しますが、すべての文法がチー::パース（）通話中に存在しないと述べました。 何が問題なのでしょうか？複合文法をもっと意味のあるものにするにはどうすればよいですか？

P.S. の#defineにのconst自動を変更し、=記号を削除する場合 - それは成功:)（チー::パース（）戻り偽が、少なくともリターンで）。あなたの重複を越えていくつかの無料アドバイスを与える

Answer 1

：Assigning parsers to auto variables

は、簡単なFNTサンプルを解析してみましょう：

info face="Arial" size=32 bold=0 italic=0 charset="" unicode=1 stretchH=100 smooth=1 aa=1 padding=0,0,0,0 spacing=1,1 outline=0 
common lineHeight=32 base=26 scaleW=256 scaleH=256 pages=0 packed=0 alphaChnl=1 redChnl=0 greenChnl=0 blueChnl=0 
chars count=0 

注：

1. は無意味な空白を可能にするためにスキッパーを使用しています。それはeol重要
2. を保つため、この場合は、ルールにdouble % ','
3. 使用BOOST_SPIRIT_DEBUGを行うことにより、多値（"property=0,0,0"スタイル）を可能にqi::blankを使用する暗黙の語彙素（Boost spirit skipper issues）

ため

宣言skipperlessルール

Live On Coliru

#define BOOST_SPIRIT_DEBUG 
#include <boost/spirit/include/qi.hpp> 
#include <fstream> 

namespace qi = boost::spirit::qi; 

int main() { 
    using It = boost::spirit::istream_iterator; 
    qi::rule<It> 
     word = +qi::alnum, 
     literal = '"' >> *(qi::char_ - '"') >> '"'; 
    qi::rule<It, std::string()> 
     value = qi::raw[literal | qi::double_ % ',']; 

    BOOST_SPIRIT_DEBUG_NODES((word)(literal)(value)) 

    const auto pair  = qi::copy(word >> '=' >> value); 
    const auto line  = qi::copy(word >> (+ pair) >> qi::eol); 
    const auto document = qi::copy(+ line); 

    std::ifstream in("input.fnt"); 
    in.unsetf(std::ios::skipws); 
    It begin(in), end; 

    bool ok = qi::phrase_parse(begin, end, document, qi::blank); 
    std::cout << std::boolalpha << ok << '\n'; 
} 

プリント：デバッグ情報付き

true 

：

<word> 
    <try>info face="Arial" si</try> 
    <success> face="Arial" size=3</success> 
    <attributes>[]</attributes> 
</word> 
<word> 
    <try>face="Arial" size=32</try> 
    <success>="Arial" size=32 bol</success> 
    <attributes>[]</attributes> 
</word> 
<value> 
    <try>"Arial" size=32 bold</try> 
    <literal> 
    <try>"Arial" size=32 bold</try> 
    <success> size=32 bold=0 ital</success> 
    <attributes>[]</attributes> 
    </literal> 
    <success> size=32 bold=0 ital</success> 
    <attributes>[[", A, r, i, a, l, "]]</attributes> 
</value> 
<word> 
    <try>size=32 bold=0 itali</try> 
    <success>=32 bold=0 italic=0 </success> 
    <attributes>[]</attributes> 
</word> 
<value> 
    <try>32 bold=0 italic=0 c</try> 
    <literal> 
    <try>32 bold=0 italic=0 c</try> 
    <fail/> 
    </literal> 
    <success> bold=0 italic=0 cha</success> 
    <attributes>[[3, 2]]</attributes> 
</value> 
<word> 
    <try>bold=0 italic=0 char</try> 
    <success>=0 italic=0 charset=</success> 
    <attributes>[]</attributes> 
</word> 
<value> 
    <try>0 italic=0 charset="</try> 
    <literal> 
    <try>0 italic=0 charset="</try> 
    <fail/> 
    </literal> 
    <success> italic=0 charset=""</success> 
    <attributes>[[0]]</attributes> 
</value> 
<word> 
    <try>italic=0 charset="" </try> 
    <success>=0 charset="" unicod</success> 
    <attributes>[]</attributes> 
</word> 
<value> 
    <try>0 charset="" unicode</try> 
    <literal> 
    <try>0 charset="" unicode</try> 
    <fail/> 
    </literal> 
    <success> charset="" unicode=</success> 
    <attributes>[[0]]</attributes> 
</value> 
<word> 
    <try>charset="" unicode=1</try> 
    <success>="" unicode=1 stretc</success> 
    <attributes>[]</attributes> 
</word> 
<value> 
    <try>"" unicode=1 stretch</try> 
    <literal> 
    <try>"" unicode=1 stretch</try> 
    <success> unicode=1 stretchH=</success> 
    <attributes>[]</attributes> 
    </literal> 
    <success> unicode=1 stretchH=</success> 
    <attributes>[[", "]]</attributes> 
</value> 
<word> 
    <try>unicode=1 stretchH=1</try> 
    <success>=1 stretchH=100 smoo</success> 
    <attributes>[]</attributes> 
</word> 
<value> 
    <try>1 stretchH=100 smoot</try> 
    <literal> 
    <try>1 stretchH=100 smoot</try> 
    <fail/> 
    </literal> 
    <success> stretchH=100 smooth</success> 
    <attributes>[[1]]</attributes> 
</value> 
<word> 
    <try>stretchH=100 smooth=</try> 
    <success>=100 smooth=1 aa=1 p</success> 
    <attributes>[]</attributes> 
</word> 
<value> 
    <try>100 smooth=1 aa=1 pa</try> 
    <literal> 
    <try>100 smooth=1 aa=1 pa</try> 
    <fail/> 
    </literal> 
    <success> smooth=1 aa=1 paddi</success> 
    <attributes>[[1, 0, 0]]</attributes> 
</value> 
<word> 
    <try>smooth=1 aa=1 paddin</try> 
    <success>=1 aa=1 padding=0,0,</success> 
    <attributes>[]</attributes> 
</word> 
<value> 
    <try>1 aa=1 padding=0,0,0</try> 
    <literal> 
    <try>1 aa=1 padding=0,0,0</try> 
    <fail/> 
    </literal> 
    <success> aa=1 padding=0,0,0,</success> 
    <attributes>[[1]]</attributes> 
</value> 
<word> 
    <try>aa=1 padding=0,0,0,0</try> 
    <success>=1 padding=0,0,0,0 s</success> 
    <attributes>[]</attributes> 
</word> 
<value> 
    <try>1 padding=0,0,0,0 sp</try> 
    <literal> 
    <try>1 padding=0,0,0,0 sp</try> 
    <fail/> 
    </literal> 
    <success> padding=0,0,0,0 spa</success> 
    <attributes>[[1]]</attributes> 
</value> 
<word> 
    <try>padding=0,0,0,0 spac</try> 
    <success>=0,0,0,0 spacing=1,1</success> 
    <attributes>[]</attributes> 
</word> 
<value> 
    <try>0,0,0,0 spacing=1,1 </try> 
    <literal> 
    <try>0,0,0,0 spacing=1,1 </try> 
    <fail/> 
    </literal> 
    <success> spacing=1,1 outline</success> 
    <attributes>[[0, ,, 0, ,, 0, ,, 0]]</attributes> 
</value> 
<word> 
    <try>spacing=1,1 outline=</try> 
    <success>=1,1 outline=0\ncommo</success> 
    <attributes>[]</attributes> 
</word> 
<value> 
    <try>1,1 outline=0\ncommon</try> 
    <literal> 
    <try>1,1 outline=0\ncommon</try> 
    <fail/> 
    </literal> 
    <success> outline=0\ncommon li</success> 
    <attributes>[[1, ,, 1]]</attributes> 
</value> 
<word> 
    <try>outline=0\ncommon lin</try> 
    <success>=0\ncommon lineHeight</success> 
    <attributes>[]</attributes> 
</word> 
<value> 
    <try>0\ncommon lineHeight=</try> 
    <literal> 
    <try>0\ncommon lineHeight=</try> 
    <fail/> 
    </literal> 
    <success>\ncommon lineHeight=3</success> 
    <attributes>[[0]]</attributes> 
</value> 
<word> 
    <try>\ncommon lineHeight=3</try> 
    <fail/> 
</word> 
<word> 
    <try>common lineHeight=32</try> 
    <success> lineHeight=32 base=</success> 
    <attributes>[]</attributes> 
</word> 
<word> 
    <try>lineHeight=32 base=2</try> 
    <success>=32 base=26 scaleW=2</success> 
    <attributes>[]</attributes> 
</word> 
<value> 
    <try>32 base=26 scaleW=25</try> 
    <literal> 
    <try>32 base=26 scaleW=25</try> 
    <fail/> 
    </literal> 
    <success> base=26 scaleW=256 </success> 
    <attributes>[[3, 2]]</attributes> 
</value> 
<word> 
    <try>base=26 scaleW=256 s</try> 
    <success>=26 scaleW=256 scale</success> 
    <attributes>[]</attributes> 
</word> 
<value> 
    <try>26 scaleW=256 scaleH</try> 
    <literal> 
    <try>26 scaleW=256 scaleH</try> 
    <fail/> 
    </literal> 
    <success> scaleW=256 scaleH=2</success> 
    <attributes>[[2, 6]]</attributes> 
</value> 
<word> 
    <try>scaleW=256 scaleH=25</try> 
    <success>=256 scaleH=256 page</success> 
    <attributes>[]</attributes> 
</word> 
<value> 
    <try>256 scaleH=256 pages</try> 
    <literal> 
    <try>256 scaleH=256 pages</try> 
    <fail/> 
    </literal> 
    <success> scaleH=256 pages=0 </success> 
    <attributes>[[2, 5, 6]]</attributes> 
</value> 
<word> 
    <try>scaleH=256 pages=0 p</try> 
    <success>=256 pages=0 packed=</success> 
    <attributes>[]</attributes> 
</word> 
<value> 
    <try>256 pages=0 packed=0</try> 
    <literal> 
    <try>256 pages=0 packed=0</try> 
    <fail/> 
    </literal> 
    <success> pages=0 packed=0 al</success> 
    <attributes>[[2, 5, 6]]</attributes> 
</value> 
<word> 
    <try>pages=0 packed=0 alp</try> 
    <success>=0 packed=0 alphaChn</success> 
    <attributes>[]</attributes> 
</word> 
<value> 
    <try>0 packed=0 alphaChnl</try> 
    <literal> 
    <try>0 packed=0 alphaChnl</try> 
    <fail/> 
    </literal> 
    <success> packed=0 alphaChnl=</success> 
    <attributes>[[0]]</attributes> 
</value> 
<word> 
    <try>packed=0 alphaChnl=1</try> 
    <success>=0 alphaChnl=1 redCh</success> 
    <attributes>[]</attributes> 
</word> 
<value> 
    <try>0 alphaChnl=1 redChn</try> 
    <literal> 
    <try>0 alphaChnl=1 redChn</try> 
    <fail/> 
    </literal> 
    <success> alphaChnl=1 redChnl</success> 
    <attributes>[[0]]</attributes> 
</value> 
<word> 
    <try>alphaChnl=1 redChnl=</try> 
    <success>=1 redChnl=0 greenCh</success> 
    <attributes>[]</attributes> 
</word> 
<value> 
    <try>1 redChnl=0 greenChn</try> 
    <literal> 
    <try>1 redChnl=0 greenChn</try> 
    <fail/> 
    </literal> 
    <success> redChnl=0 greenChnl</success> 
    <attributes>[[1]]</attributes> 
</value> 
<word> 
    <try>redChnl=0 greenChnl=</try> 
    <success>=0 greenChnl=0 blueC</success> 
    <attributes>[]</attributes> 
</word> 
<value> 
    <try>0 greenChnl=0 blueCh</try> 
    <literal> 
    <try>0 greenChnl=0 blueCh</try> 
    <fail/> 
    </literal> 
    <success> greenChnl=0 blueChn</success> 
    <attributes>[[0]]</attributes> 
</value> 
<word> 
    <try>greenChnl=0 blueChnl</try> 
    <success>=0 blueChnl=0\nchars </success> 
    <attributes>[]</attributes> 
</word> 
<value> 
    <try>0 blueChnl=0\nchars c</try> 
    <literal> 
    <try>0 blueChnl=0\nchars c</try> 
    <fail/> 
    </literal> 
    <success> blueChnl=0\nchars co</success> 
    <attributes>[[0]]</attributes> 
</value> 
<word> 
    <try>blueChnl=0\nchars cou</try> 
    <success>=0\nchars count=0\n</success> 
    <attributes>[]</attributes> 
</word> 
<value> 
    <try>0\nchars count=0\n</try> 
    <literal> 
    <try>0\nchars count=0\n</try> 
    <fail/> 
    </literal> 
    <success>\nchars count=0\n</success> 
    <attributes>[[0]]</attributes> 
</value> 
<word> 
    <try>\nchars count=0\n</try> 
    <fail/> 
</word> 
<word> 
    <try>chars count=0\n</try> 
    <success> count=0\n</success> 
    <attributes>[]</attributes> 
</word> 
<word> 
    <try>count=0\n</try> 
    <success>=0\n</success> 
    <attributes>[]</attributes> 
</word> 
<value> 
    <try>0\n</try> 
    <literal> 
    <try>0\n</try> 
    <fail/> 
    </literal> 
    <success>\n</success> 
    <attributes>[[0]]</attributes> 
</value> 
<word> 
    <try>\n</try> 
    <fail/> 
</word> 
<word> 
    <try></try> 
    <fail/> 
</word>