促进：：精神:气：：规则或结构包含气：：规则的解析结果
促进：：精神:气：：规则或结构包含气：：规则的解析结果
提问于 2014-12-03 15:03:29
我要做的是在运行时从ABNF语法文件创建一个解析器。我已经在qi：：语法中实现了所有ABNF规则，如下所示：
typedef /*qi::rule or struct containing qi::rule*/ parserRule
[...] //all other ABNF rules according to RFC 5234
rule =
(
rulename[qi::_a = qi::_1] >>
definedAs >>
elements[qi::_b = qi::_1] >>
cNl
)[qi::_val = px::bind(&AbnfParserFactory::fromRule, &factory, qi::_a, qi::_b)];
rulelist =
+(
rule[px::push_back(qi::_a, qi::_1)] |
(*cWsp >> cNl)
) >>
eps[qi::_val = px::bind(&AbnfParserFactory::fromRulelist, &factory, qi::_a)];
qi::rule<Iterator, std::map<std::string, parserRule>(), qi::locals<std::vector<parserRule> > > rulelist;
qi::rule<Iterator, parserRule(), qi::locals<std::string>, qi::locals<parserRule> > rule;
[...] // all other ABNF rules在ParserFactory内部，根据语法中的读内容创建了一个新的qi：：规则：
std::map<std::string, ReturnType> fromRulelist(std::vector<ReturnType> &rules)
{
// return a map with <rulename, rule>
};
parserRule fromRule(std::string &name, parserRule &rule)
{
//name the rule an return it
rule.name(name);
return rule;
};问题在于parserRule的类型。
如果我使用qi::rule作为类型(就像我通常想要的那样)，我将丢失在ParserFactory中分配的每个规则名称(如在fromRule中)。我想这是精神内部工作方式造成的(=操作符总是创建一个新的、未命名的规则。=用于分配px::bind函数结果)
但是，如果我试图将qi::rule封装到一个结构中以避免这个问题，那么我就无法再编译我的代码并进行精神调试。以下是我尝试过的：
typedef qi::rule<std::string::const_iterator, std::string()> FactoryRuleType;
struct parserRule
{
FactoryRuleType mRule;
};
BOOST_FUSION_ADAPT_STRUCT(
parserRule,
(FactoryRuleType, mRule)
)
[...] //rule definitions like above
debug(rule);
debug(rulelist);
[...] //debug all other rules这将给我带来大量编译错误(这是很长的一段时间才能在这里发布)。为了解决这个问题，我已经找了好几天了，但没有任何运气。我希望我能提到足够的细节。
任何帮助都是非常感谢的。
编译输出节选：
/usr/include/boost/proto/operators.hpp:295:9: note: template argument deduction/substitution failed:
/usr/include/boost/proto/operators.hpp: In substitution of ‘template<class Left, class Right> const typename boost::proto::detail::enable_binary<boost::proto::domainns_::deduce_domain, boost::proto::detail::not_a_grammar, boost::mpl::or_<boost::proto::is_extension<Arg>, boost::proto::is_extension<Right> >, boost::proto::tagns_::tag::shift_left, Left&, Right&>::type boost::proto::exprns_::operator<<(Left&, Right&) [with Left = std::basic_ostream<char>; Right = const boost::spirit::qi::reference<const boost::spirit::qi::rule<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char> >, std::basic_string<char>()> >]’:
/usr/include/boost/spirit/home/support/attributes.hpp:1226:17: required from ‘static void boost::spirit::traits::print_attribute_debug<Out, T, Enable>::call_impl3(Out&, const T_&, mpl_::false_) [with T_ = boost::spirit::qi::reference<const boost::spirit::qi::rule<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char> >, std::basic_string<char>()> >; Out = std::basic_ostream<char>; T = boost::spirit::qi::reference<const boost::spirit::qi::rule<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char> >, std::basic_string<char>()> >; Enable = void; mpl_::false_ = mpl_::bool_<false>]’
/usr/include/boost/spirit/home/support/attributes.hpp:1242:67: required from ‘static void boost::spirit::traits::print_attribute_debug<Out, T, Enable>::call_impl2(Out&, const T_&, mpl_::false_) [with T_ = boost::spirit::qi::reference<const boost::spirit::qi::rule<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char> >, std::basic_string<char>()> >; Out = std::basic_ostream<char>; T = boost::spirit::qi::reference<const boost::spirit::qi::rule<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char> >, std::basic_string<char>()> >; Enable = void; mpl_::false_ = mpl_::bool_<false>]’
/usr/include/boost/spirit/home/support/attributes.hpp:1277:52: required from ‘static void boost::spirit::traits::print_attribute_debug<Out, T, Enable>::call_impl(Out&, const T_&, mpl_::true_) [with T_ = boost::spirit::qi::reference<const boost::spirit::qi::rule<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char> >, std::basic_string<char>()> >; Out = std::basic_ostream<char>; T = boost::spirit::qi::reference<const boost::spirit::qi::rule<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char> >, std::basic_string<char>()> >; Enable = void; mpl_::true_ = mpl_::bool_<true>]’
/usr/include/boost/spirit/home/support/attributes.hpp:1283:52: required from ‘static void boost::spirit::traits::print_attribute_debug<Out, T, Enable>::call(Out&, const T&) [with Out = std::basic_ostream<char>; T = boost::spirit::qi::reference<const boost::spirit::qi::rule<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char> >, std::basic_string<char>()> >; Enable = void]’
/usr/include/boost/spirit/home/support/attributes.hpp:1303:53: required from ‘void boost::spirit::traits::print_attribute(Out&, const T&) [with Out = std::basic_ostream<char>; T = boost::spirit::qi::reference<const boost::spirit::qi::rule<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char> >, std::basic_string<char>()> >]’
/usr/include/boost/spirit/home/support/attributes.hpp:1196:57: [ skipping 34 instantiation contexts, use -ftemplate-backtrace-limit=0 to disable ]
/usr/include/boost/function/function_template.hpp:722:7: required from ‘boost::function4<R, T1, T2, T3, T4>::function4(Functor, typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, int>::type) [with Functor = boost::spirit::qi::debug_handler<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char> >, boost::spirit::context<boost::fusion::cons<FactoryReturnType&, boost::fusion::nil>, boost::fusion::vector0<> >, boost::spirit::unused_type, boost::spirit::qi::simple_trace>; R = bool; T0 = __gnu_cxx::__normal_iterator<const char*, std::basic_string<char> >&; T1 = const __gnu_cxx::__normal_iterator<const char*, std::basic_string<char> >&; T2 = boost::spirit::context<boost::fusion::cons<FactoryReturnType&, boost::fusion::nil>, boost::fusion::vector0<> >&; T3 = const boost::spirit::unused_type&; typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, int>::type = int]’
/usr/include/boost/function/function_template.hpp:1069:16: required from ‘boost::function<R(T0, T1, T2, T3)>::function(Functor, typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, int>::type) [with Functor = boost::spirit::qi::debug_handler<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char> >, boost::spirit::context<boost::fusion::cons<FactoryReturnType&, boost::fusion::nil>, boost::fusion::vector0<> >, boost::spirit::unused_type, boost::spirit::qi::simple_trace>; R = bool; T0 = __gnu_cxx::__normal_iterator<const char*, std::basic_string<char> >&; T1 = const __gnu_cxx::__normal_iterator<const char*, std::basic_string<char> >&; T2 = boost::spirit::context<boost::fusion::cons<FactoryReturnType&, boost::fusion::nil>, boost::fusion::vector0<> >&; T3 = const boost::spirit::unused_type&; typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, int>::type = int]’
/usr/include/boost/function/function_template.hpp:1124:5: required from ‘typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, boost::function<R(T0, T1, T2, T3)>&>::type boost::function<R(T0, T1, T2, T3)>::operator=(Functor) [with Functor = boost::spirit::qi::debug_handler<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char> >, boost::spirit::context<boost::fusion::cons<FactoryReturnType&, boost::fusion::nil>, boost::fusion::vector0<> >, boost::spirit::unused_type, boost::spirit::qi::simple_trace>; R = bool; T0 = __gnu_cxx::__normal_iterator<const char*, std::basic_string<char> >&; T1 = const __gnu_cxx::__normal_iterator<const char*, std::basic_string<char> >&; T2 = boost::spirit::context<boost::fusion::cons<FactoryReturnType&, boost::fusion::nil>, boost::fusion::vector0<> >&; T3 = const boost::spirit::unused_type&; typename boost::enable_if_c<boost::type_traits::ice_not<boost::is_integral<Functor>::value>::value, boost::function<R(T0, T1, T2, T3)>&>::type = boost::function<bool(__gnu_cxx::__normal_iterator<const char*, std::basic_string<char> >&, const __gnu_cxx::__normal_iterator<const char*, std::basic_string<char> >&, boost::spirit::context<boost::fusion::cons<FactoryReturnType&, boost::fusion::nil>, boost::fusion::vector0<> >&, const boost::spirit::unused_type&)>&]’
/usr/include/boost/spirit/home/qi/nonterminal/debug_handler.hpp:122:13: required from ‘void boost::spirit::qi::debug(boost::spirit::qi::rule<Iterator, T1, T2, T3, T4>&) [with Iterator = __gnu_cxx::__normal_iterator<const char*, std::basic_string<char> >; T1 = FactoryReturnType(); T2 = boost::spirit::unused_type; T3 = boost::spirit::unused_type; T4 = boost::spirit::unused_type]’
../src/AbnfReader.hpp:350:14: required from ‘AbnfRules<Iterator>::AbnfRules() [with Iterator = __gnu_cxx::__normal_iterator<const char*, std::basic_string<char> >]’
../src/AbnfReader.cpp:27:12: required from here
/usr/include/boost/proto/operators.hpp:295:9: error: no type named ‘type’ in ‘struct boost::proto::detail::enable_binary<boost::proto::domainns_::deduce_domain, boost::proto::detail::not_a_grammar, boost::mpl::or_<boost::proto::is_extension<std::basic_ostream<char> >, boost::proto::is_extension<const boost::spirit::qi::reference<const boost::spirit::qi::rule<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char> >, std::basic_string<char>()> > >, mpl_::bool_<false>, mpl_::bool_<false>, mpl_::bool_<false> >, boost::proto::tagns_::tag::shift_left, std::basic_ostream<char>&, const boost::spirit::qi::reference<const boost::spirit::qi::rule<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char> >, std::basic_string<char>()> >&>’
make: *** [src/AbnfReader.o] Error 1回答 2
Stack Overflow用户
回答已采纳
发布于 2014-12-06 20:38:25
这太尴尬了。当我试图像sehe建议的那样编写一个SSCCE时，我发现我的方法实际上一直在起作用。为了解决这个问题我遇到了很多麻烦.:C
下面是我想要做的事情的一个例子。虽然有效，但行为仍然有点奇怪，这也是我认为它不是这样工作的原因。
#include <boost/spirit/include/qi.hpp>
#include <boost/spirit/include/phoenix.hpp>
namespace qi = boost::spirit::qi;
namespace px = boost::phoenix;
namespace ascii = boost::spirit::ascii;
typedef qi::rule<std::string::const_iterator, std::string()> parserRule;
namespace std
{
std::ostream& operator<<(std::ostream& stream, const parserRule& val);
}
std::ostream& std::operator<<(std::ostream& stream, const parserRule& val)
{
stream << "RULE( " << val.name();
stream << " )";
return stream;
}
class Factory
{
public:
Factory(){}
parserRule createParser(std::string str)
{
parserRule r;
r = qi::char_(str);
r.name("FactoryRule");
std::cout << r.name() << " now parses >" + str + "<" << std::end;
return r;
}
};
template <typename Iterator>
struct TestGrammar : qi::grammar<Iterator, parserRule()>
{
TestGrammar() : TestGrammar::base_type(start, "Test grammar")
{
start = stringRule.alias();
stringRule = (
ascii::char_("'") >>
*(ascii::char_ - ascii::char_("'"))[qi::_a += qi::_1] >>
ascii::char_("'")
)[qi::_val = px::bind(&Factory::createParser, &factory, qi::_a)];
start.name("Start");
stringRule.name("StringRule");
qi::debug(start); // shows "RULE( unnamed-rule )"
qi::debug(stringRule); // shows "RULE( unnamed-rule )"
}
qi::rule<Iterator, parserRule() > start;
qi::rule<Iterator, parserRule(), qi::locals<std::string> > stringRule;
Factory factory;
};
int main()
{
typedef std::string::const_iterator iterator_type;
typedef TestGrammar<iterator_type> TGrammar;
TGrammar test_parser;
std::string test = "parse THIS!";
std::string input = "'"+test+"'";
parserRule result;
std::string::const_iterator iter = input.begin();
std::string::const_iterator end = input.end();
bool r = parse(iter, end, test_parser, result);
if (r && iter == end)
{
std::cout << "-------------------------\n";
std::cout << "1st Parsing succeeded\n";
std::cout << "-------------------------\n";
}
else
{
std::string rest(iter, end);
std::cout << "-------------------------\n";
std::cout << "1st Parsing failed\n";
std::cout << "stopped at: \"" << rest << "\"\n";
std::cout << "-------------------------\n";
}
iterator_type first(test.begin()), last(test.end());
qi::debug(result); //shows correct rule name
r = qi::phrase_parse(first, last, result, boost::spirit::ascii::space);
if (r && iter == end)
{
std::cout << "-------------------------\n";
std::cout << "2nd Parsing succeeded\n";
std::cout << "-------------------------\n";
}
else
{
std::string rest(first, last);
std::cout << "-------------------------\n";
std::cout << "2nd Parsing failed\n";
std::cout << "stopped at: \"" << rest << "\"\n";
std::cout << "-------------------------\n";
}
}这是输出：
FactoryRule now parses >parse THIS!<
<Start>
<try>'parse THIS!'</try>
<StringRule>
<try>'parse THIS!'</try>
<success></success>
<attributes>[[RULE( unnamed-rule )]]</attributes><locals>(parse THIS!)</locals>
</StringRule>
<success></success>
<attributes>[[RULE( unnamed-rule )]]</attributes>
</Start>
-------------------------
1st Parsing succeeded
-------------------------
<FactoryRule>
<try>parse THIS!</try>
<success>arse THIS!</success>
<attributes>[[p]]</attributes>
</FactoryRule>
-------------------------
2nd Parsing succeeded
-------------------------如您所见，调试规则start和stringRule将始终将“规则(未命名-规则)”显示为属性。这使我相信，由于在分配=-operator结果时使用了px::bind，所以分配的规则名丢失了。因为调试result规则会显示正确的名称，所以我假设“未命名规则”输出并不显示正确的最终合成属性，而是显示当前的“空”属性。
当我看到“未命名的规则”和花费了很多天的时间试图解决这个问题，甚至在没有通过调试result规则来测试整个事情的情况下在这里问的时候，我感到非常遗憾。
不管怎样，谢谢你帮我。我希望这至少对其他人有用。
Stack Overflow用户
发布于 2014-12-03 15:31:06
这里有两个问题，仅凭经验，无需编写进一步的代码：
- 单元素适配结构会产生问题，请参阅:链接来了。
- 调试信息需要调试打印特征的专门化(返回到
ostream流)。显然，对于qi::rule来说，这一点还没有完成。所以要么加进去。 也许，只是也许您可以使包含的结构iostream-能够避免它(但我担心融合适应可能优先。值得一试)
问:是的，你是对的。我必须在运行时动态地编写语法。为了确保这是可能的，我已经编写了一堆测试片段，它们按预期工作。
- 直截了当地说:精神不是实现这一目标的工具。灵性是一个工具，它从"praser表达式“(即表达式模板)生成静态编译的语法。总体目标是编译时，使用静态多态性进行完全优化。我建议可能创建一组运行时多态解析器组件(反过来，您可以使用精灵:实现这些组件)，并从它们中构建动态语法。
一种可能的中间路线是使用
qi::lazy和一组预定义的不可变的“原子”规则(所以不是动态合成的)，并使用这些引用的“原子”规则组成解析器。 - 基本上，只要您不尝试动态组合表达式模板(而是准备好的类型擦除的非终端)，您就应该没事。
如果你需要更多的话，你很快就会到UB的。有些时候，您可以使用
boost::proto::deep_copy来解决问题，但这是有局限性的。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/27274969
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