从另一种解析器前pressions一个可变参数列表产生精神解析器前pressions [英] Generating Spirit parser expressions from a variadic list of alternative parser expressions
问题描述
我在寻找实现可变参数函数,该函数列表提振精神:: ::气规则,并扩展到列表格式前pression最简单的方法:规则|规则2 |规则3 | ....假设规则合成无属性。你的帮助是非常AP preciated。
的#include<升压/配置/ warning_disable.hpp>
#包括LT&;升压/精神/有/ qi.hpp>
#包括LT&;串GT;
#包括LT&;&iostream的GT;
#包括LT&;升压/精神/有/ phoenix_operator.hpp>命名空间补气=的boost ::精神::补气;
命名空间的pH =提振::凤;
命名空间ASCII =的boost ::精神:: ASCII;
使用boost ::精神::补气:: phrase_parse;
使用boost ::精神::齐:: ASCII ::空间;
使用boost ::精神:: ISO8859_1 :: char_;补气的typedef ::规则<的std ::字符串::为const_iterator,ASCII ::空间类型> mrule_t;
补气的typedef ::规则<标准::字符串::为const_iterator,标准::字符串()> wrule_t;
//如何演绎expandBitwise()的返回类型?模板< typename的T>
ŧexpandBitwise(T& T公司)
{
返回t.rule_;
}模板< typename的T,typename的...尾>
ŧexpandBitwise(T& T公司,尾部和放大器; ...尾)
{
返回t.rule_ | expandBitwise(尾...);
}结构TStruct
{
mrule_t rule_;
模板< typename的T,typename的R>
TStruct(T&安培; RVAR,常量标准::字符串&放大器;名称,R&安培;规则):
rule_(齐亮::(名称)GT;>规则[PH :: REF(RVAR)=气:: _ 1])
{}
};模板< typename的T,typename的...尾>
无效mparse(常量标准::字符串&放大器;线,T& T公司,尾部和放大器; ...尾)
{
标准::字符串::为const_iterator F,L; F = line.begin();
L = line.end();
//我想在这里展开的规则...
//if(phrase_parse(f,l,expandBitwise(t,tail...),space)及&放大器;˚F== L) 如果(phrase_parse(F,L,t.rule_,空间)及&放大器;˚F== L)
性病::法院LT&;<经分析:<<线474;<的std :: ENDL;
其他
性病::法院LT&;<语法错误:<<线474;<的std :: ENDL;
}诠释的main()
{
wrule_t rword = +〜空间; 标准::字符串PAR1,PAR2,PAR3,PAR4; TStruct R1(PAR1, - 一个,rword);
TStruct R2(par2的, - B,rword);
TStruct R3(PAR3, - C,rword);
TStruct R4(PAR4, - D,rword); mparse(ABC 8.81,R1,R2,R3,R4);
mparse( - 一个atoken,R1,R2,R3,R4);
mparse( - B btoken,R1,R2,R3,R4);
mparse( - Çctoken,R1,R2,R3,R4);
mparse( - Ðdtoken,R1,R2,R3,R4); 返回0;
}
的感谢您快速提示!我只是想你code,除非我做错了什么......我得到这样的输出:
语法错误:ABC 8.81负担:-a atoken语法错误:-b btoken语法错误: - çctoken语法错误:-d dtoken
的 - <一个href=\"http://stackoverflow.com/questions/16177184/return-type-deduction-of-boost-spirit-ex$p$pssion-made-of-variadic-function-expan/16179565#comment23128636_16179565\">G. Civardi 1小时前
块引用>好了,所以,我不能离开它单独:/
原来有未定义行为参与的,因为在这种分析器前pressions被传递到
expandBitwise
的方式,并成为复制:提升原前pression模板没有被设计成被复制,因为它们可能包含对临时引用,他的一生中其包含完整-EX pression月底结束
有关详情,请背景,在的零到2秒60英里!
块引用>在与
rule_.alias()调整长(长)时间
和的boost ::原:: deepcopy的
我已经达到了以下解决方案(顺便说一下,并不需要一个辅助函数所有,再):模板&LT; typename的...尾&GT;
无效mparse(常量标准::字符串&放大器;线,尾部和放大器; ...尾)
{
自动分析器=提振::融合::倍(
提高::领带(PH ::绑定(安培; TStruct :: rule_,ARG1)(尾)...)
齐:: EPS(假),
deepcopy_(ARG2 | ARG1)
); 汽车F =开始(线),L =端(线); 如果(气:: phrase_parse(F,L,分析器,ASCII ::空间))
性病::法院LT&;&LT; 经分析:&LT;&LT;线474;&LT;的std :: ENDL;
其他
性病::法院LT&;&LT; 语法错误:&LT;&LT;线474;&LT;的std :: ENDL; 如果(F!= 1)
性病::法院LT&;&LT; 剩余未解析:'&LT;&LT;标准::字符串(F,L)LT;&LT; '\\ n;
}针对UB的保护是
deepcopy的_()
调用,这是琐碎多态性可调用适配器的boost ::原:: deepcopy的
:结构正是deepcopy
{
模板&LT; typename的E&GT;结构的结果{的typedef typename的升压::原:: ::的result_of&DEEP_COPY LT; E&GT; ::类型类型; }; 模板&LT; typename的E&GT;
类型名造成&LT; E&GT; ::类型
运算符()(E&const的放大器;表达式)常量{
返回的boost ::原:: DEEP_COPY(表达式);
}
};静态常量pH值::功能&LT; deepcopy的&GT; deepcopy_;有了这个code,你瞧,输出变为:
语法错误:ABC 8.81
剩余未解析:'ABC 8.81
解析:-a atoken
解析:-b btoken
解析:-c ctoken
解析:-d dtoken
再见作为奖励,在code现在允许你使用圣灵的内置调试()功能(取消注释行):
&LT;&-d GT;
&LT;尽量&GT; ABC 8.81&LT; /&尝试GT;
&LT;失败/&GT;
&LT; / - D&GT;
&LT;&-c GT;
&LT;尽量&GT; ABC 8.81&LT; /&尝试GT;
&LT;失败/&GT;
&LT; / - C&GT;
&LT;&-b GT;
&LT;尽量&GT; ABC 8.81&LT; /&尝试GT;
&LT;失败/&GT;
&LT; / - B&GT;
&LT;&-a GT;
&LT;尽量&GT; ABC 8.81&LT; /&尝试GT;
&LT;失败/&GT;
&LT; / - A&GT;
语法错误:ABC 8.81
剩余未解析:'ABC 8.81
与测试
- 升压1_54_0
- GCC 4.7.2,4.8.x,3.2锵
- 注意
的#define
■哪些是显著。
块引用>FULL code
的#define BOOST_RESULT_OF_USE_DECLTYPE
#定义BOOST_SPIRIT_USE_PHOENIX_V3
#包括LT&;升压/融合/调整/ boost_tuple.hpp&GT;
#包括LT&;升压/融合/有/ fold.hpp&GT;
#包括LT&;升压/精神/有/ qi.hpp&GT;
#包括LT&;升压/精神/有/ phoenix.hpp&GT;命名空间补气=的boost ::精神::补气;
命名空间的pH =提振::凤;
命名空间ASCII =的boost ::精神:: ASCII;
使用命名空间的pH :: arg_names;补气的typedef ::规则&LT;的std ::字符串::为const_iterator,ASCII ::空间类型&GT; mrule_t;
补气的typedef ::规则&LT;的std ::字符串::为const_iterator,标准::字符串()&GT; wrule_t;结构TStruct
{
mrule_t rule_;
模板&LT; typename的T,typename的R&GT;
TStruct(T&安培; RVAR,常量标准::字符串&放大器;名称,R&安培;规则):
rule_(齐亮::(名称)GT;&GT;规则[PH :: REF(RVAR)=气:: _ 1])
{
rule_.name(名);
//调试(rule_);
}
};结构正是deepcopy
{
模板&LT; typename的E&GT;结构的结果{的typedef typename的升压::原:: ::的result_of&DEEP_COPY LT; E&GT; ::类型类型; }; 模板&LT; typename的E&GT;
类型名造成&LT; E&GT; ::类型
运算符()(E&const的放大器;表达式)常量{
返回的boost ::原:: DEEP_COPY(表达式);
}
};静态常量pH值::功能&LT; deepcopy的&GT; deepcopy_;模板&LT; typename的...尾&GT;
无效mparse(常量标准::字符串&放大器;线,尾部和放大器; ...尾)
{
自动分析器=提振::融合::倍(
提高::领带(PH ::绑定(安培; TStruct :: rule_,ARG1)(尾)...)
齐:: EPS(假),
deepcopy_(ARG2 | ARG1)
); 汽车F =开始(线),L =端(线); 如果(气:: phrase_parse(F,L,分析器,ASCII ::空间))
性病::法院LT&;&LT; 经分析:&LT;&LT;线474;&LT;的std :: ENDL;
其他
性病::法院LT&;&LT; 语法错误:&LT;&LT;线474;&LT;的std :: ENDL; 如果(F!= 1)
性病::法院LT&;&LT; 剩余未解析:'&LT;&LT;标准::字符串(F,L)LT;&LT; '\\ n;
}诠释的main()
{
wrule_t rword = +〜ASCII ::空间; 标准::字符串PAR1,PAR2,PAR3,PAR4; TStruct R1(PAR1,-a,rword);
TStruct R2(PAR2,-b,rword);
TStruct R3(PAR3,-c,rword);
TStruct R4(PAR4,D,rword); mparse(ABC 8.81,R1,R2,R3,R4);
mparse( - 一个atoken,R1,R2,R3,R4);
mparse( - B btoken,R1,R2,R3,R4);
mparse( - Çctoken,R1,R2,R3,R4);
mparse( - Ðdtoken,R1,R2,R3,R4); 性病::法院LT&;&LT; 再见\\ n;
}I'm looking for the simplest way to implement variadic function which takes list of boost::spirit::qi rules and expands the list into expression of format: rule1 | rule2 | rule3 |.... Let's assume that the rules synthesize no attribute. Your kind help is very much appreciated.
#include <boost/config/warning_disable.hpp> #include <boost/spirit/include/qi.hpp> #include <string> #include <iostream> #include <boost/spirit/include/phoenix_operator.hpp> namespace qi = boost::spirit::qi; namespace ph = boost::phoenix; namespace ascii = boost::spirit::ascii; using boost::spirit::qi::phrase_parse; using boost::spirit::qi::ascii::space; using boost::spirit::iso8859_1::char_; typedef qi::rule<std::string::const_iterator,ascii::space_type> mrule_t; typedef qi::rule< std::string::const_iterator,std::string() > wrule_t;
//How to deduce expandBitwise() return type ? template<typename T> T expandBitwise(T& t) { return t.rule_; } template<typename T,typename ...Tail> T expandBitwise(T& t,Tail& ...tail) { return t.rule_ | expandBitwise(tail...); } struct TStruct { mrule_t rule_; template<typename T,typename R> TStruct( T& rVar,const std::string&name, R& rule ) : rule_( qi::lit( name ) >> rule[ ph::ref( rVar )=qi::_1 ] ) {} }; template<typename T,typename ...Tail> void mparse(const std::string& line,T& t,Tail& ...tail) { std::string::const_iterator f,l; f=line.begin(); l=line.end();
// I would like to expand the rules here ... //if(phrase_parse(f,l,expandBitwise(t,tail...),space ) && f==l) if( phrase_parse(f, l, t.rule_, space ) && f==l ) std::cout<<"Parsed:"<<line<<std::endl; else std::cout<<"Syntax error:"<<line<<std::endl; } int main() { wrule_t rword=+~space; std::string par1,par2,par3,par4; TStruct r1( par1,"-a", rword ); TStruct r2( par2,"-b", rword ); TStruct r3( par3,"-c", rword ); TStruct r4( par4,"-d", rword ); mparse("abc 8.81" ,r1,r2,r3,r4); mparse("-a atoken" ,r1,r2,r3,r4); mparse("-b btoken" ,r1,r2,r3,r4); mparse("-c ctoken" ,r1,r2,r3,r4); mparse("-d dtoken" ,r1,r2,r3,r4); return 0; }
解决方案Thank you for a quick hint! I've just tried your code and unless I do something wrong ... I get this output:
Syntax error:abc 8.81 Parsed:-a atoken Syntax error:-b btoken Syntax error:-c ctoken Syntax error:-d dtoken
– G. Civardi 2 hours agoOkay, so, I couldn't leave it alone :/
Turns out there was Undefined Behaviour involved, because of the way in which parser expressions were being passed to
expandBitwise
and being copied: Boost Proto expression templates weren't designed to be copied as they may contain references to temporaries, whose lifetime ends at the end of their containing full-expression.See for more background, the discussion at Zero to 60 MPH in 2 seconds!
After a long (long) time of tweaking with
rule_.alias()
andboost::proto::deepcopy
I have reached the following solution (which, incidentally, doesn't need a helper function at all, anymore):template<typename ...Tail> void mparse(const std::string& line,Tail& ...tail) { auto parser = boost::fusion::fold( boost::tie(ph::bind(&TStruct::rule_, arg1)(tail)...), qi::eps(false), deepcopy_(arg2 | arg1) ); auto f=begin(line), l=end(line); if( qi::phrase_parse(f, l, parser, ascii::space ) ) std::cout << "Parsed:" << line << std::endl; else std::cout << "Syntax error:" << line << std::endl; if (f!=l) std::cout << "Remaining unparsed: '" << std::string(f,l) << "'\n"; }
The protection against UB is the
deepcopy_()
invocation, which is a trivial polymorphic callable adaptor forboost::proto::deepcopy
:struct DeepCopy { template<typename E> struct result { typedef typename boost::proto::result_of::deep_copy<E>::type type; }; template<typename E> typename result<E>::type operator()(E const& expr) const { return boost::proto::deep_copy(expr); } }; static const ph::function<DeepCopy> deepcopy_;
With this code, lo and behold, the output becomes:
Syntax error:abc 8.81 Remaining unparsed: 'abc 8.81' Parsed:-a atoken Parsed:-b btoken Parsed:-c ctoken Parsed:-d dtoken Bye
As a bonus, the code now allows you to use Spirit's builtin debug() capabilities (uncomment that line):
<-d> <try>abc 8.81</try> <fail/> </-d> <-c> <try>abc 8.81</try> <fail/> </-c> <-b> <try>abc 8.81</try> <fail/> </-b> <-a> <try>abc 8.81</try> <fail/> </-a> Syntax error:abc 8.81 Remaining unparsed: 'abc 8.81'
Tested with
- Boost 1_54_0
- GCC 4.7.2, 4.8.x, Clang 3.2
- Note the
#define
s which are significant.
FULL CODE
#define BOOST_RESULT_OF_USE_DECLTYPE #define BOOST_SPIRIT_USE_PHOENIX_V3 #include <boost/fusion/adapted/boost_tuple.hpp> #include <boost/fusion/include/fold.hpp> #include <boost/spirit/include/qi.hpp> #include <boost/spirit/include/phoenix.hpp> namespace qi = boost::spirit::qi; namespace ph = boost::phoenix; namespace ascii = boost::spirit::ascii; using namespace ph::arg_names; typedef qi::rule<std::string::const_iterator,ascii::space_type> mrule_t; typedef qi::rule<std::string::const_iterator,std::string() > wrule_t; struct TStruct { mrule_t rule_; template<typename T,typename R> TStruct( T& rVar,const std::string&name, R& rule ) : rule_( qi::lit(name) >> rule[ ph::ref(rVar) = qi::_1 ] ) { rule_.name(name); // debug(rule_); } }; struct DeepCopy { template<typename E> struct result { typedef typename boost::proto::result_of::deep_copy<E>::type type; }; template<typename E> typename result<E>::type operator()(E const& expr) const { return boost::proto::deep_copy(expr); } }; static const ph::function<DeepCopy> deepcopy_; template<typename ...Tail> void mparse(const std::string& line,Tail& ...tail) { auto parser = boost::fusion::fold( boost::tie(ph::bind(&TStruct::rule_, arg1)(tail)...), qi::eps(false), deepcopy_(arg2 | arg1) ); auto f=begin(line), l=end(line); if( qi::phrase_parse(f, l, parser, ascii::space ) ) std::cout << "Parsed:" << line << std::endl; else std::cout << "Syntax error:" << line << std::endl; if (f!=l) std::cout << "Remaining unparsed: '" << std::string(f,l) << "'\n"; } int main() { wrule_t rword=+~ascii::space; std::string par1,par2,par3,par4; TStruct r1( par1, "-a", rword ); TStruct r2( par2, "-b", rword ); TStruct r3( par3, "-c", rword ); TStruct r4( par4, "-d", rword ); mparse("abc 8.81" ,r1,r2,r3,r4); mparse("-a atoken" ,r1,r2,r3,r4); mparse("-b btoken" ,r1,r2,r3,r4); mparse("-c ctoken" ,r1,r2,r3,r4); mparse("-d dtoken" ,r1,r2,r3,r4); std::cout << "Bye\n"; }
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