我正在尝试将一个简单的命令行解析器与SPIRIT放在一起而不需要语义操作。 我正在使用BOOST 1.52，但我想避免使用C ++ 11功能。语法具有以下语法：
[-p num1] [-j] [--jobs num2] str1 str2
可选参数可以按任何顺序排列。我成功解析了可选参数。一旦我添加了额外的强制性两个字符串解析器就会中断。当我尝试明确记下“rstart”属性并使用“auto”避免类型推导时，它就会中断。任何帮助或建议非常感谢！
#include <iostream>
#include <string>
#include <vector>
#include <iterator>
#include <boost/spirit/include/qi.hpp>
#include <boost/optional.hpp>
#include <boost/fusion/include/boost_tuple.hpp>
bool parse_line( const std::string&str,bool useStart1 )
{
bool rc=false;
namespace qi = boost::spirit::qi;
using boost::spirit::ascii::space_type;
using boost::spirit::ascii::space;
using boost::spirit::ascii::char_;
std::string::const_iterator iter( str.begin() );
std::size_t num1 =88;
bool bool1 =false;
std::size_t num2 =88;
std::string str1,str2;
qi::rule< std::string::const_iterator,std::string() > rstring=+~space;
qi::rule< std::string::const_iterator,std::size_t() ,space_type >
rOption1=qi::lit( "-p" ) >> qi::int_;
qi::rule< std::string::const_iterator,bool() ,space_type >
rOption2=qi::lit( "-j" ) >> qi::attr(true);
qi::rule< std::string::const_iterator,std::size_t() ,space_type >
rOption3=qi::lit( "--jobs" ) >> qi::int_;
#if defined(AAA)
qi::rule< std::string::const_iterator,
boost::spirit::ascii::space_type,
boost::tuple< boost::optional<std::size_t>,
boost::optional<bool>,
boost::optional<std::size_t >
>
>
#endif
auto rstart1 = ( rOption1 ^ rOption2 ^ rOption3 ) ;
auto rstart2 = ( rOption1 ^ rOption2 ^ rOption3 ) >> rstring >> rstring;
if( useStart1 )
qi::phrase_parse( iter,str.end(),
( qi::lit( "-p" ) >> qi::int_ ) ^
( qi::lit( "-j" ) >> qi::attr(true) ) ^
( qi::lit( "--jobs" ) >> qi::int_ ),space,num1,bool1,num2);
else
{
// qi::phrase_parse(
// iter,str.end(),rstart2,space,num1,bool1,num2,str1,str2);
}
if(iter==str.begin())
iter=str.begin(); //NOP
else
if(iter!=str.end())
std::cerr<<"syntax error: "<<std::string(iter,str.end())<<"!\n\n";
else
rc=true;
std::cout << "num1:" << num1 << std::endl;
std::cout << "bool1:"<< bool1 << std::endl;
std::cout << "num2:" << num2 << std::endl;
std::cout << "str1:" << str1 << std::endl;
std::cout << "str2:" << str2 << std::endl;
return rc;
}
int main( int argc,char**argv )
{
std::vector< std::string > testData1;
testData1.push_back( "-p 100 -j" );
testData1.push_back( "-j -p 100 --jobs 16" );
testData1.push_back( "--jobs 16 -j -p 100" );
for( std::vector< std::string >::const_iterator it=testData1.begin();
it!=testData1.end(); ++it )
{
std::cout << "\nparsing string:" << *it << std::endl;
parse_line( *it,true );
}
std::vector< std::string > testData2;
testData2.push_back( "-p 100 -j ifile ofile" );
testData2.push_back( "-j -p 100 --jobs 16 ifile ofile" );
testData2.push_back( "--jobs 16 -j -p 100 ifile ofile" );
for( std::vector< std::string >::const_iterator it=testData2.begin();
it!=testData2.end(); ++it )
{
std::cout << "\nparsing string:" << *it << std::endl;
parse_line( *it,false );
}
return 0;
}
答案 0 :(得分：3)
您面临的问题是组合规则的属性基本上是：
tuple< tuple<size_t,bool,size_t>, std::string, std::string >
并且通过将你的变量逐个放在对phrase_parse的调用上，基本上就是：
tuple< size_t, bool, size_t, std::string, std::string >
由于属性传播在精神上的运作方式，这就是正在发生的事情：
整个tuple<size_t,bool,size_t>被分配给你的num1（忽略bool和第二个size_t），之后精灵试图将第一个字符串分配给你的bool，导致你有错误。
我认为最简单的解决方法是创建一个自定义结构来保存反映规则结构的结果。
#include <iostream>
#include <string>
#include <vector>
#include <iterator>
#include <boost/spirit/include/qi.hpp>
#include <boost/fusion/include/adapt_struct.hpp>
struct optional_command_line_options
{
int num1;
bool bool1;
int num2;
};
struct command_line_options
{
optional_command_line_options opt;
std::string str1;
std::string str2;
};
BOOST_FUSION_ADAPT_STRUCT(
optional_command_line_options,
(int, num1)
(bool, bool1)
(int, num2)
)
BOOST_FUSION_ADAPT_STRUCT(
command_line_options,
(optional_command_line_options, opt)
(std::string, str1)
(std::string, str2)
)
bool parse_line( const std::string&str )
{
bool rc=false;
namespace qi = boost::spirit::qi;
using boost::spirit::ascii::space;
using boost::spirit::ascii::char_;
std::string::const_iterator iter( str.begin() );
command_line_options options;
options.opt.num1=88;
options.opt.bool1=false;
options.opt.num2=88;
qi::rule< std::string::const_iterator, std::string() > rstring=+~space;
qi::rule<std::string::const_iterator, boost::spirit::ascii::space_type,optional_command_line_options() > trule;
trule=
( qi::lit( "-p" ) >> qi::int_ ) ^
( qi::lit( "-j" ) >> qi::attr(true) ) ^
( qi::lit( "--jobs" ) >> qi::int_ )
;
qi::rule< std::string::const_iterator, boost::spirit::ascii::space_type, command_line_options() >arule;
arule = -trule >> rstring >> rstring;
bool result=qi::phrase_parse( iter,str.end(),
arule,
space,
options
);
if(result && iter==str.end())
{
std::cout << "Parse successful." << std::endl;
rc=true;
}
else
{
std::cerr<<"syntax error: "<<std::string(iter,str.end())<<"!\n\n";
}
std::cout << std::boolalpha;
std::cout << "num1:" << options.opt.num1 << std::endl;
std::cout << "bool1:"<< options.opt.bool1 << std::endl;
std::cout << "num2:" << options.opt.num2 << std::endl;
std::cout << "str1:" << options.str1 << std::endl;
std::cout << "str2:" << options.str2 << std::endl;
return rc;
}
int main( int /*argc*/,char**/*argv*/ )
{
std::vector< std::string > testData;
testData.push_back( "-p 100 -j ifile ofile" );
testData.push_back( "-j -p 100 --jobs 16 ifile ofile" );
testData.push_back( "--jobs 16 -j -p 100 ifile ofile" );
testData.push_back( "--jobs 16 -p 100 ifile ofile" );
testData.push_back( "ifile ofile" );
for( std::vector< std::string >::const_iterator it=testData.begin();
it!=testData.end(); ++it )
{
std::cout << "\nparsing string:" << *it << std::endl;
parse_line( *it );
}
return 0;
}
PS：你不能直接分配用auto声明的规则，这些规则中嵌入了文字（例如字符串或数字），而不使用boost :: proto :: deep_copy;
auto trule = boost::proto::deep_copy(qi::lit( "-p" ) >> qi::int_);
有一个名为BOOST_SPIRIT_AUTO的宏，它更易于使用：
#define BOOST_SPIRIT_AUTO(domain_, name, expr) \
typedef boost::proto::result_of:: \
deep_copy<BOOST_TYPEOF(expr)>::type name##_expr_type; \
BOOST_SPIRIT_ASSERT_MATCH( \
boost::spirit::domain_::domain, name##_expr_type); \
BOOST_AUTO(name, boost::proto::deep_copy(expr));
BOOST_SPIRIT_AUTO(qi,trule,qi::lit( "-p" ) >> qi::int_);