From a previous post I found a way to parse with boost::spirit a struct of this type:
"parameter" : {
"name" : "MyName" ,
"type" : "MyType" ,
"unit" : "MyUnit" ,
"cardinality" : "MyCardinality",
"value" : "MyValue"
}
It's a simple JSON with key-value pairs. Now I want to parse this struct regardless to variable orders. I.e. I want to parse into the same object also this struct:
"parameter" : {
"type" : "MyType" ,
"value" : "MyValue" ,
"unit" : "MyUnit" ,
"cardinality" : "MyCardinality",
"name" : "MyName"
}
I know that I can use the ^ operator in order to parse data in any order but I dont't know how to handles commas at ends of lines but last. How can I parse both structures?
This is the @sehe code from previous post. Grammar is defined here.
#define BOOST_SPIRIT_DEBUG
#include <boost/fusion/include/io.hpp>
#include <boost/spirit/include/qi.hpp>
#include <boost/fusion/include/adapt_struct.hpp>
// This is pasted and copied from another header file
namespace StateMachine {
namespace Private {
struct LuaParameterData {
std::wstring name;
std::wstring type;
std::wstring unit;
std::wstring cardinality;
std::wstring value;
};
} // namespace Private
} // namespace StateMachine
BOOST_FUSION_ADAPT_STRUCT(
StateMachine::Private::LuaParameterData,
(std::wstring, name)
(std::wstring, type)
(std::wstring, unit)
(std::wstring, cardinality)
(std::wstring, value)
)
namespace qi = boost::spirit::qi;
// From here original file continues
namespace StateMachine {
namespace Private {
template<typename Iterator>
struct LuaParameterDataParser : qi::grammar<Iterator, LuaParameterData(), qi::ascii::space_type>
{
LuaParameterDataParser() : LuaParameterDataParser::base_type(start)
{
quotedString = qi::lexeme['"' >> +(qi::ascii::char_ - '"') >> '"'];
start =
qi::lit("\"parameter\"")
>> ':'
>> '{'
>> qi::lit("\"name\"" ) >> ':' >> quotedString >> ','
>> qi::lit("\"type\"" ) >> ':' >> quotedString >> ','
>> qi::lit("\"unit\"" ) >> ':' >> quotedString >> ','
>> qi::lit("\"cardinality\"") >> ':' >> quotedString >> ','
>> qi::lit("\"value\"" ) >> ':' >> quotedString
>> '}'
;
BOOST_SPIRIT_DEBUG_NODES((start)(quotedString));
}
qi::rule<Iterator, std::string(), qi::ascii::space_type> quotedString;
qi::rule<Iterator, LuaParameterData(), qi::ascii::space_type> start;
};
} // namespace Private
} // namespace StateMachine
int main() {
using It = std::string::const_iterator;
std::string const input = R"(
"parameter" : {
"name" : "name" ,
"type" : "type" ,
"unit" : "unit" ,
"cardinality" : "cardinality",
"value" : "value"
}
)";
It f = input.begin(),
l = input.end();
StateMachine::Private::LuaParameterDataParser<It> p;
StateMachine::Private::LuaParameterData data;
bool ok = qi::phrase_parse(f, l, p, qi::ascii::space, data);
if (ok) {
std::wcout << L"Parsed: \n";
std::wcout << L"\tname: " << data.name << L'\n';
std::wcout << L"\ttype: " << data.type << L'\n';
std::wcout << L"\tunit: " << data.unit << L'\n';
std::wcout << L"\tcardinality: " << data.cardinality << L'\n';
std::wcout << L"\tvalue: " << data.value << L'\n';
} else {
std::wcout << L"Parse failure\n";
}
if (f!=l)
std::wcout << L"Remaining unparsed: '" << std::wstring(f,l) << L"'\n";
}
