我想将我的规则(制作)分成不同的类。我在Boost :: Spirit :: Qi中找不到任何例子来做这件事。
Boost示例都显示了一个语法类中的规则。
这是我的语法:
<start> ::= @ ( <event_bool_no_param> )
<event_bool_no_param> ::= RAMPING_COMPLETED | STATE_TIMEOUT
这是我的语法课:
template <typename Iterator, typename Skipper>
struct Event_Grammar
: boost::spirit::qi::grammar<Iterator, Skipper>
{
Event_Grammar() : Event_Grammar::base_type(start)
{
using boost::spirit::ascii::char_;
using boost::spirit::qi::eps;
start =
(
char_('@') >> char_('(') >> Event_Bool_No_Param<Iterator>() >> char_(')')
)
;
}
boost::spirit::qi::rule<Iterator, Skipper> start;
};
这是我的另一个语法课:
template <typename Iterator>
struct Event_Bool_No_Param
: qi::grammar<Iterator>
{
Event_Bool_No_Param ()
: Event_Bool_No_Param::base_type(start)
{
using qi::lexeme;
using qi::lit;
start =
lit("STATE_TIMEOUT") | lit("RAMPING_COMPLETED") | lit("PASSIVE_MEAS_COMPLETED")
;
}
qi::rule<Iterator> start;
};
我收到文本“@ ( STATE_TIMEOUT )
”的未处理异常错误。
这是最近的(最近的)堆栈跟踪:
Event_Grammar.exe!boost::spirit::qi::sequence_base<boost::spirit::qi::sequence<boost::fusion::cons<boost::spirit::qi::literal_char<boost::spirit::char_encoding::ascii,0,0>,boost::fusion::cons<boost::spirit::qi::literal_char<boost::spirit::char_encoding::ascii,0,0>,boost::fusion::cons<boost::spirit::qi::reference<boost::spirit::qi::rule<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> >,boost::spirit::unused_type,boost::spirit::unused_type,boost::spirit::unused_type,boost::spirit::unused_type> const >,boost::fusion::cons<boost::spirit::qi::literal_char<boost::spirit::char_encoding::ascii,0,0>,boost::fusion::nil_> > > > >,boost::fusion::cons<boost::spirit::qi::literal_char<boost::spirit::char_encoding::ascii,0,0>,boost::fusion::cons<boost::spirit::qi::literal_char<boost::spirit::char_encoding::ascii,0,0>,boost::fusion::cons<boost::spirit::qi::reference<boost::spirit::qi::rule<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> >,boost::spirit::unused_type,boost::spirit::unused_type,boost::spirit::unused_type,boost::spirit::unused_type> const >,boost::fusion::cons<boost::spirit::qi::literal_char<boost::spirit::char_encoding::ascii,0,0>,boost::fusion::nil_> > > > >::parse_impl<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> >,boost::spirit::context<boost::fusion::cons<boost::spirit::unused_type &,boost::fusion::nil_>,boost::fusion::vector0<void> >,boost::spirit::qi::char_class<boost::spirit::tag::char_code<boost::spirit::tag::space,boost::spirit::char_encoding::ascii> >,boost::spirit::unused_type>(std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> > & first, const std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> > & last, boost::spirit::context<boost::fusion::cons<boost::spirit::unused_type &,boost::fusion::nil_>,boost::fusion::vector0<void> > & context, const boost::spirit::qi::char_class<boost::spirit::tag::char_code<boost::spirit::tag::space,boost::spirit::char_encoding::ascii> > & skipper, boost::spirit::unused_type & attr_, boost::mpl::bool_<0> __formal) Line 88 + 0x55 bytes C++
Event_Grammar.exe!boost::spirit::qi::sequence_base<boost::spirit::qi::sequence<boost::fusion::cons<boost::spirit::qi::literal_char<boost::spirit::char_encoding::ascii,0,0>,boost::fusion::cons<boost::spirit::qi::literal_char<boost::spirit::char_encoding::ascii,0,0>,boost::fusion::cons<boost::spirit::qi::reference<boost::spirit::qi::rule<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> >,boost::spirit::unused_type,boost::spirit::unused_type,boost::spirit::unused_type,boost::spirit::unused_type> const >,boost::fusion::cons<boost::spirit::qi::literal_char<boost::spirit::char_encoding::ascii,0,0>,boost::fusion::nil_> > > > >,boost::fusion::cons<boost::spirit::qi::literal_char<boost::spirit::char_encoding::ascii,0,0>,boost::fusion::cons<boost::spirit::qi::literal_char<boost::spirit::char_encoding::ascii,0,0>,boost::fusion::cons<boost::spirit::qi::reference<boost::spirit::qi::rule<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> >,boost::spirit::unused_type,boost::spirit::unused_type,boost::spirit::unused_type,boost::spirit::unused_type> const >,boost::fusion::cons<boost::spirit::qi::literal_char<boost::spirit::char_encoding::ascii,0,0>,boost::fusion::nil_> > > > >::parse<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> >,boost::spirit::context<boost::fusion::cons<boost::spirit::unused_type &,boost::fusion::nil_>,boost::fusion::vector0<void> >,boost::spirit::qi::char_class<boost::spirit::tag::char_code<boost::spirit::tag::space,boost::spirit::char_encoding::ascii> >,boost::spirit::unused_type>(std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> > & first, const std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> > & last, boost::spirit::context<boost::fusion::cons<boost::spirit::unused_type &,boost::fusion::nil_>,boost::fusion::vector0<void> > & context, const boost::spirit::qi::char_class<boost::spirit::tag::char_code<boost::spirit::tag::space,boost::spirit::char_encoding::ascii> > & skipper, boost::spirit::unused_type & attr_) Line 125 C++
Event_Grammar.exe!boost::spirit::qi::detail::parser_binder<boost::spirit::qi::sequence<boost::fusion::cons<boost::spirit::qi::literal_char<boost::spirit::char_encoding::ascii,0,0>,boost::fusion::cons<boost::spirit::qi::literal_char<boost::spirit::char_encoding::ascii,0,0>,boost::fusion::cons<boost::spirit::qi::reference<boost::spirit::qi::rule<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> >,boost::spirit::unused_type,boost::spirit::unused_type,boost::spirit::unused_type,boost::spirit::unused_type> const >,boost::fusion::cons<boost::spirit::qi::literal_char<boost::spirit::char_encoding::ascii,0,0>,boost::fusion::nil_> > > > >,boost::mpl::bool_<0> >::call<std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> >,boost::spirit::qi::char_class<boost::spirit::tag::char_code<boost::spirit::tag::space,boost::spirit::char_encoding::ascii> >,boost::spirit::context<boost::fusion::cons<boost::spirit::unused_type &,boost::fusion::nil_>,boost::fusion::vector0<void> > >(std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> > & first, const std::_String_const_iterator<char,std::char_traits<char>,std::allocator<char> > & last, boost::spirit::context<boost::fusion::cons<boost::spirit::unused_type &,boost::fusion::nil_>,boost::fusion::vector0<void> > & context, const boost::spirit::qi::char_class<boost::spirit::tag::char_code<boost::spirit::tag::space,boost::spirit::char_encoding::ascii> > & skipper, boost::mpl::bool_<0> __formal) Line 44 C++
这是发生异常的代码位置,function_template.hpp#761:
result_type operator()(BOOST_FUNCTION_PARMS) const
{
if (this->empty())
boost::throw_exception(bad_function_call());
return get_vtable()->invoker
(this->functor BOOST_FUNCTION_COMMA BOOST_FUNCTION_ARGS);
}
所以,我的问题是:
我正在使用:
答案 0 :(得分:3)
首先是问题:
所有规则都需要在单个语法类中吗?
绝对不是。语法只是一种将规则组合在一起并在需要时提供附加状态的机制。语法只是一个类/结构,所以它是一个非常方便的设备来封装语法的概念。
如何在规则中引用语法类?
你需要一个语法实例。暂时会导致悲伤。
我上课时的错误在哪里?
错误在于你在制定规则时创造临时性。您需要将语法(或规则)的实例组合成其他语法和规则。
例如,以下内容:
<强> Live On Coliru 强>
#include <boost/spirit/home/qi.hpp>
namespace qi = boost::spirit::qi;
namespace ascii = boost::spirit::qi::ascii;
template <typename Iterator>
struct Event_Bool_No_Param : qi::grammar<Iterator>
{
Event_Bool_No_Param ()
: Event_Bool_No_Param::base_type(start)
{
using qi::lit;
start =
lit("STATE_TIMEOUT") | lit("RAMPING_COMPLETED") | lit("PASSIVE_MEAS_COMPLETED")
;
}
qi::rule<Iterator> start;
};
template <typename Iterator, typename Skipper>
struct Event_Grammar : boost::spirit::qi::grammar<Iterator, Skipper>
{
Event_Grammar() : Event_Grammar::base_type(start)
{
using boost::spirit::ascii::char_;
start =
char_('@') >> char_('(') >> event_no_param >> char_(')')
;
}
qi::rule<Iterator, Skipper> start;
Event_Bool_No_Param<Iterator> event_no_param;
};
int main()
{
using iterator_t = std::string::const_iterator;
std::string input = "@ ( STATE_TIMEOUT )";
iterator_t iter = input.begin();
iterator_t end = input.end();
Event_Grammar<iterator_t,ascii::space_type> grammar;
bool ok = qi::phrase_parse( iter, end
, grammar
, ascii::space
);
return ok? 0 : 255;
}
至于使用哪个OR符号,|
和||
不是一回事。你很可能想要|
。
|
- 是另一种选择。
A | B | C
- 解析
A
或B
或C
||
- 是顺序或操作符( sequential or )
A || B
*解析A
后跟可选的B
或解析B
A >> -B | B
答案 1 :(得分:1)
这里有两个问题对我来说并不明显:
规则可以使用其他语法,但需要具有其他语法的实例。
Event_Grammar
类现在看起来像:
#include "event_bool_no_param.hpp"
template <typename Iterator, typename Skipper>
struct Event_Grammar
: boost::spirit::qi::grammar<Iterator, Skipper>
{
Event_Grammar() : Event_Grammar::base_type(start)
{
using boost::spirit::ascii::char_;
using boost::spirit::qi::eps;
using qi::lit;
// Notice the identifier "grammar_bool_no_param"
// which is an instance of the grammer / rule Event_Bool_No_Param.
start =
(
char_('@') >> char_('(') >> grammar_bool_no_param >> char_(')')
)
;
}
// *** A rule or grammar needs an instance!
Event_Bool_No_Param<Iterator> grammar_bool_no_param;
boost::spirit::qi::rule<Iterator, Skipper> start;
};
在规则中,&#34; OR&#34;的符号是"||"
而不是"|"
:
template <typename Iterator>
struct Event_Bool_No_Param
: qi::grammar<Iterator>
{
Event_Bool_No_Param ()
: Event_Bool_No_Param::base_type(start)
{
using qi::lexeme;
using qi::lit;
start =
lit("STATE_TIMEOUT") || lit("RAMPING_COMPLETED") || lit("PASSIVE_MEAS_COMPLETED")
;
}
qi::rule<Iterator> start;
};