我有以下代码要修改，但是我对Boost-spirit完全陌生。
我知道RE是精打细算的，但不知道该怎么做。
这是解析器。
Parser() : Parser::base_type(root)
{
braces = lit('{') >> *(iso8859_1::space) >> lit('}');
str = lexeme[lit('"') >> raw[*(~iso8859_1::char_('"'))] >> lit('"')];
tolleaf = raw[+(~iso8859_1::char_("\"{}= \t\r\n"))];
leaf = raw[+(iso8859_1::alnum | iso8859_1::char_("-._:"))];
taglist = lit('{') >> omit[*(iso8859_1::space)] >> lexeme[( ( str | skip[tolleaf] ) % *(iso8859_1::space) )] >> omit[*(iso8859_1::space)] >> lit('}');
object = raw[lit('{') >> *(root) >> *(iso8859_1::space) >> lit('}')];
objlist = raw[lit('{') >> *( *(iso8859_1::space) >> object[&pushObj] ) >> *(iso8859_1::space) >> lit('}')];
assign = raw[(*(iso8859_1::space) >> ( leaf[&setLHS] | str[&setLHS]) >> *(iso8859_1::space) >> lit('=')
>> *(iso8859_1::space)
>> ( leaf[&setRHSleaf] | str[&setRHSleaf] | taglist[&setRHStaglist] | objlist[&setRHSobjlist] | object[&setRHSobject] )
>> *(iso8859_1::space))];
root = +(assign | braces);
str.name("str");
leaf.name("leaf");
taglist.name("taglist");
object.name("object");
objlist.name("objlist");
assign.name("assign");
braces.name("braces");
root.name("root");
}
这是我尝试解析的格式:
employees=
{
{
province_pop_id=
{
province_id=1
index=0
type=9
}
count=1750
}
{
province_pop_id=
{
province_id=1
index=1
type=9
}
count=34
}
}
问题是双{{。如果我只有一个
blahblah=
{
value=
{
2
}
}
它工作正常。
我知道
objlist = raw[lit('{') >> *( *(iso8859_1::space) >> object[&pushObj] ) >> *(iso8859_1::space) >> lit('}')];
必须更改，但我不确定如何更改。
最佳答案
因此，为了向您展示我的意思，我整理了语法。
看到它 Live on Coliru
Parser() : Parser::base_type(root)
{
using namespace qi::iso8859_1;
braces =
'{' >> qi::eps >> '}'
;
str = qi::lexeme [
'"'
>> *~char_('"')
>> '"'
]
;
tolleaf = qi::lexeme [
+(~char_("\"{}= \t\r\n"))
]
;
leaf = qi::lexeme [
+(alnum | char_("-._:"))
]
;
taglist =
'{'
>> -str % tolleaf
>> '}'
;
object =
'{'
>> *root
>> '}'
;
objlist =
'{'
>> *object
>> '}'
;
assign =
(leaf | str)
>> '='
>> (leaf | str | taglist | objlist | object)
;
root =
+(assign | braces)
;
BOOST_SPIRIT_DEBUG_NODES((root)(braces)(str)(tolleaf)(leaf)(taglist)(objlist)(object)(assign));
}
它包含了很多令人惊讶的东西
skip[]和lexeme[]的存在清楚地表明，已使用Skipper声明了规则(如果未声明，则所有规则隐式地为“lexemes”)注意我没有看过实际的语法。看起来这也可以改进，但是我没有时间尝试去理解预期的语法。但是，您可以看到它解析了您在问题中显示的代码段:
完整代码
#define BOOST_SPIRIT_DEBUG
#include <boost/spirit/include/qi.hpp>
#include <boost/spirit/include/phoenix.hpp>
namespace qi = boost::spirit::qi;
template <typename It, typename Skipper = qi::iso8859_1::space_type>
struct Parser : qi::grammar<It, Skipper>
{
Parser() : Parser::base_type(root)
{
using namespace qi::iso8859_1;
braces =
'{' >> qi::eps >> '}'
;
str = qi::lexeme [
'"'
>> *~char_('"')
>> '"'
]
;
tolleaf = qi::lexeme [
+(~char_("\"{}= \t\r\n"))
]
;
leaf = qi::lexeme [
+(alnum | char_("-._:"))
]
;
taglist =
'{'
>> -str % tolleaf
>> '}'
;
object =
'{'
>> *root
>> '}'
;
objlist =
'{'
>> *object
>> '}'
;
assign =
(leaf | str)
>> '='
>> (leaf | str | taglist | objlist | object)
;
root =
+(assign | braces)
;
BOOST_SPIRIT_DEBUG_NODES((root)(braces)(str)(tolleaf)(leaf)(taglist)(objlist)(object)(assign));
}
private:
qi::rule<It, Skipper> root, braces, str, tolleaf, leaf, taglist, objlist, object, assign;
};
int main()
{
typedef boost::spirit::istream_iterator It;
std::cin.unsetf(std::ios::skipws);
It f(std::cin), l;
namespace iso8859_1 = qi::iso8859_1;
Parser<It, iso8859_1::space_type> p;
try
{
bool ok = qi::phrase_parse(f,l,p,iso8859_1::space);
if (ok) std::cout << "parse success\n";
else std::cerr << "parse failed: '" << std::string(f,l) << "'\n";
if (f!=l) std::cerr << "trailing unparsed: '" << std::string(f,l) << "'\n";
return ok;
} catch(const qi::expectation_failure<It>& e)
{
std::string frag(e.first, e.last);
std::cerr << e.what() << "'" << frag << "'\n";
}
return false;
}
输出量
这是BOOST_SPIRIT_DEBUG打印的内容:
<root>
<try>employees=\n{\n{\n p</try>
<assign>
<try>employees=\n{\n{\n p</try>
<leaf>
<try>employees=\n{\n{\n p</try>
<success>=\n{\n{\n province_p</success>
<attributes>[]</attributes>
</leaf>
<leaf>
<try>\n{\n{\n province_po</try>
<fail/>
</leaf>
<str>
<try>{\n{\n province_pop</try>
<fail/>
</str>
<taglist>
<try>{\n{\n province_pop</try>
<str>
<try>\n{\n province_pop_</try>
<fail/>
</str>
<tolleaf>
<try>{\n province_pop_i</try>
<fail/>
</tolleaf>
<fail/>
</taglist>
<objlist>
<try>{\n{\n province_pop</try>
<object>
<try>\n{\n province_pop_</try>
<root>
<try>\n province_pop_id</try>
<assign>
<try>\n province_pop_id</try>
<leaf>
<try>\n province_pop_id</try>
<success>=\n {\n province</success>
<attributes>[]</attributes>
</leaf>
<leaf>
<try>\n {\n province_</try>
<fail/>
</leaf>
<str>
<try>{\n province_id=1\n</try>
<fail/>
</str>
<taglist>
<try>{\n province_id=1\n</try>
<str>
<try>\n province_id=1\n </try>
<fail/>
</str>
<tolleaf>
<try>province_id=1\n in</try>
<success>=1\n index=0\n t</success>
<attributes>[]</attributes>
</tolleaf>
<str>
<try>=1\n index=0\n t</try>
<fail/>
</str>
<tolleaf>
<try>=1\n index=0\n t</try>
<fail/>
</tolleaf>
<fail/>
</taglist>
<objlist>
<try>{\n province_id=1\n</try>
<object>
<try>\n province_id=1\n </try>
<fail/>
</object>
<fail/>
</objlist>
<object>
<try>{\n province_id=1\n</try>
<root>
<try>\n province_id=1\n </try>
<assign>
<try>\n province_id=1\n </try>
<leaf>
<try>\n province_id=1\n </try>
<success>=1\n index=0\n t</success>
<attributes>[]</attributes>
</leaf>
<leaf>
<try>1\n index=0\n ty</try>
<success>\n index=0\n typ</success>
<attributes>[]</attributes>
</leaf>
<success>\n index=0\n typ</success>
<attributes>[]</attributes>
</assign>
<assign>
<try>\n index=0\n typ</try>
<leaf>
<try>\n index=0\n typ</try>
<success>=0\n type=9\n }\n</success>
<attributes>[]</attributes>
</leaf>
<leaf>
<try>0\n type=9\n }\n </try>
<success>\n type=9\n }\n </success>
<attributes>[]</attributes>
</leaf>
<success>\n type=9\n }\n </success>
<attributes>[]</attributes>
</assign>
<assign>
<try>\n type=9\n }\n </try>
<leaf>
<try>\n type=9\n }\n </try>
<success>=9\n }\n count=1</success>
<attributes>[]</attributes>
</leaf>
<leaf>
<try>9\n }\n count=17</try>
<success>\n }\n count=175</success>
<attributes>[]</attributes>
</leaf>
<success>\n }\n count=175</success>
<attributes>[]</attributes>
</assign>
<assign>
<try>\n }\n count=175</try>
<leaf>
<try>\n }\n count=175</try>
<fail/>
</leaf>
<str>
<try>}\n count=1750\n}\n\n</try>
<fail/>
</str>
<fail/>
</assign>
<braces>
<try>\n }\n count=175</try>
<fail/>
</braces>
<success>\n }\n count=175</success>
<attributes>[]</attributes>
</root>
<root>
<try>\n }\n count=175</try>
<assign>
<try>\n }\n count=175</try>
<leaf>
<try>\n }\n count=175</try>
<fail/>
</leaf>
<str>
<try>}\n count=1750\n}\n\n</try>
<fail/>
</str>
<fail/>
</assign>
<braces>
<try>\n }\n count=175</try>
<fail/>
</braces>
<fail/>
</root>
<success>\n count=1750\n}\n\n{</success>
<attributes>[]</attributes>
</object>
<success>\n count=1750\n}\n\n{</success>
<attributes>[]</attributes>
</assign>
<assign>
<try>\n count=1750\n}\n\n{</try>
<leaf>
<try>\n count=1750\n}\n\n{</try>
<success>=1750\n}\n\n{\n provi</success>
<attributes>[]</attributes>
</leaf>
<leaf>
<try>1750\n}\n\n{\n provin</try>
<success>\n}\n\n{\n province_p</success>
<attributes>[]</attributes>
</leaf>
<success>\n}\n\n{\n province_p</success>
<attributes>[]</attributes>
</assign>
<assign>
<try>\n}\n\n{\n province_p</try>
<leaf>
<try>\n}\n\n{\n province_p</try>
<fail/>
</leaf>
<str>
<try>}\n\n{\n province_po</try>
<fail/>
</str>
<fail/>
</assign>
<braces>
<try>\n}\n\n{\n province_p</try>
<fail/>
</braces>
<success>\n}\n\n{\n province_p</success>
<attributes>[]</attributes>
</root>
<root>
<try>\n}\n\n{\n province_p</try>
<assign>
<try>\n}\n\n{\n province_p</try>
<leaf>
<try>\n}\n\n{\n province_p</try>
<fail/>
</leaf>
<str>
<try>}\n\n{\n province_po</try>
<fail/>
</str>
<fail/>
</assign>
<braces>
<try>\n}\n\n{\n province_p</try>
<fail/>
</braces>
<fail/>
</root>
<success>\n\n{\n province_pop</success>
<attributes>[]</attributes>
</object>
<object>
<try>\n\n{\n province_pop</try>
<root>
<try>\n province_pop_id</try>
<assign>
<try>\n province_pop_id</try>
<leaf>
<try>\n province_pop_id</try>
<success>=\n {\n province</success>
<attributes>[]</attributes>
</leaf>
<leaf>
<try>\n {\n province_</try>
<fail/>
</leaf>
<str>
<try>{\n province_id=1\n</try>
<fail/>
</str>
<taglist>
<try>{\n province_id=1\n</try>
<str>
<try>\n province_id=1\n </try>
<fail/>
</str>
<tolleaf>
<try>province_id=1\n in</try>
<success>=1\n index=1\n t</success>
<attributes>[]</attributes>
</tolleaf>
<str>
<try>=1\n index=1\n t</try>
<fail/>
</str>
<tolleaf>
<try>=1\n index=1\n t</try>
<fail/>
</tolleaf>
<fail/>
</taglist>
<objlist>
<try>{\n province_id=1\n</try>
<object>
<try>\n province_id=1\n </try>
<fail/>
</object>
<fail/>
</objlist>
<object>
<try>{\n province_id=1\n</try>
<root>
<try>\n province_id=1\n </try>
<assign>
<try>\n province_id=1\n </try>
<leaf>
<try>\n province_id=1\n </try>
<success>=1\n index=1\n t</success>
<attributes>[]</attributes>
</leaf>
<leaf>
<try>1\n index=1\n ty</try>
<success>\n index=1\n typ</success>
<attributes>[]</attributes>
</leaf>
<success>\n index=1\n typ</success>
<attributes>[]</attributes>
</assign>
<assign>
<try>\n index=1\n typ</try>
<leaf>
<try>\n index=1\n typ</try>
<success>=1\n type=9\n }\n</success>
<attributes>[]</attributes>
</leaf>
<leaf>
<try>1\n type=9\n }\n </try>
<success>\n type=9\n }\n </success>
<attributes>[]</attributes>
</leaf>
<success>\n type=9\n }\n </success>
<attributes>[]</attributes>
</assign>
<assign>
<try>\n type=9\n }\n </try>
<leaf>
<try>\n type=9\n }\n </try>
<success>=9\n }\n count=3</success>
<attributes>[]</attributes>
</leaf>
<leaf>
<try>9\n }\n count=34</try>
<success>\n }\n count=34\n</success>
<attributes>[]</attributes>
</leaf>
<success>\n }\n count=34\n</success>
<attributes>[]</attributes>
</assign>
<assign>
<try>\n }\n count=34\n</try>
<leaf>
<try>\n }\n count=34\n</try>
<fail/>
</leaf>
<str>
<try>}\n count=34\n}\n}\n</try>
<fail/>
</str>
<fail/>
</assign>
<braces>
<try>\n }\n count=34\n</try>
<fail/>
</braces>
<success>\n }\n count=34\n</success>
<attributes>[]</attributes>
</root>
<root>
<try>\n }\n count=34\n</try>
<assign>
<try>\n }\n count=34\n</try>
<leaf>
<try>\n }\n count=34\n</try>
<fail/>
</leaf>
<str>
<try>}\n count=34\n}\n}\n</try>
<fail/>
</str>
<fail/>
</assign>
<braces>
<try>\n }\n count=34\n</try>
<fail/>
</braces>
<fail/>
</root>
<success>\n count=34\n}\n}\n</success>
<attributes>[]</attributes>
</object>
<success>\n count=34\n}\n}\n</success>
<attributes>[]</attributes>
</assign>
<assign>
<try>\n count=34\n}\n}\n</try>
<leaf>
<try>\n count=34\n}\n}\n</try>
<success>=34\n}\n}\n</success>
<attributes>[]</attributes>
</leaf>
<leaf>
<try>34\n}\n}\n</try>
<success>\n}\n}\n</success>
<attributes>[]</attributes>
</leaf>
<success>\n}\n}\n</success>
<attributes>[]</attributes>
</assign>
<assign>
<try>\n}\n}\n</try>
<leaf>
<try>\n}\n}\n</try>
<fail/>
</leaf>
<str>
<try>}\n}\n</try>
<fail/>
</str>
<fail/>
</assign>
<braces>
<try>\n}\n}\n</try>
<fail/>
</braces>
<success>\n}\n}\n</success>
<attributes>[]</attributes>
</root>
<root>
<try>\n}\n}\n</try>
<assign>
<try>\n}\n}\n</try>
<leaf>
<try>\n}\n}\n</try>
<fail/>
</leaf>
<str>
<try>}\n}\n</try>
<fail/>
</str>
<fail/>
</assign>
<braces>
<try>\n}\n}\n</try>
<fail/>
</braces>
<fail/>
</root>
<success>\n}\n</success>
<attributes>[]</attributes>
</object>
<object>
<try>\n}\n</try>
<fail/>
</object>
<success>\n</success>
<attributes>[]</attributes>
</objlist>
<success>\n</success>
<attributes>[]</attributes>
</assign>
<assign>
<try>\n</try>
<leaf>
<try>\n</try>
<fail/>
</leaf>
<str>
<try></try>
<fail/>
</str>
<fail/>
</assign>
<braces>
<try>\n</try>
<fail/>
</braces>
<success>\n</success>
<attributes>[]</attributes>
</root>
parse success
关于c++ - Boost Spirit像语法一样解析XML，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/18453062/