我在使用Visual C ++（2015）进行编译时遇到以下 live demo code 时遇到问题。该代码在GCC中可以正常工作为 demonstrated here 。请有人帮我解决这个问题。我很擅长提升精神qi解析，并且在背景中使用所有模板魔法很难发现问题。我从堆栈溢出中的 here 中获得了CSV解析的初步灵感。
在Visual C ++下报告的编译器错误（通过在线在线编译器）如下：
Error(s):
source_file.cpp(103): error C2146: syntax error: missing ';' before identifier 'context_type'
source_file.cpp(140): note: see reference to class template instantiation 'CsvGrammar<It>::final' being compiled
source_file.cpp(147): note: see reference to class template instantiation 'CsvGrammar<It>' being compiled
source_file.cpp(103): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
source_file.cpp(146): error C2079: 'CsvGrammar<std::_String_const_iterator<std::_String_val<std::_Simple_types<char>>>>::convert' uses undefined struct 'CsvGrammar<std::_String_const_iterator<std::_String_val<std::_Simple_types<char>>>>::final'
source_file.cpp(158): note: see reference to class template instantiation 'CsvGrammar<std::_String_const_iterator<std::_String_val<std::_Simple_types<char>>>>' being compiled
我桌面上的visual C ++ 2015下的错误如下所示：
1>------ Build started: Project: ConsoleApplication1, Configuration: Debug x64 ------
1> Source.cpp
1>\\geihome1\home\jcoffey\visual studio 2015\projects\consoleapplication1\consoleapplication1\source.cpp(103): error C2146: syntax error: missing ';' before identifier 'context_type'
1> \\geihome1\home\jcoffey\visual studio 2015\projects\consoleapplication1\consoleapplication1\source.cpp(140): note: see reference to class template instantiation 'CsvGrammar<It>::final' being compiled
1> \\geihome1\home\jcoffey\visual studio 2015\projects\consoleapplication1\consoleapplication1\source.cpp(147): note: see reference to class template instantiation 'CsvGrammar<It>' being compiled
1>\\geihome1\home\jcoffey\visual studio 2015\projects\consoleapplication1\consoleapplication1\source.cpp(103): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>\\geihome1\home\jcoffey\visual studio 2015\projects\consoleapplication1\consoleapplication1\source.cpp(146): error C2079: 'CsvGrammar<std::_String_const_iterator<std::_String_val<std::_Simple_types<char>>>>::convert' uses undefined struct 'CsvGrammar<std::_String_const_iterator<std::_String_val<std::_Simple_types<char>>>>::final'
1> \\geihome1\home\jcoffey\visual studio 2015\projects\consoleapplication1\consoleapplication1\source.cpp(158): note: see reference to class template instantiation 'CsvGrammar<std::_String_const_iterator<std::_String_val<std::_Simple_types<char>>>>' being compiled
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
以下是有问题的代码（也复制到上面指出的现场演示网站）
#define BOOST_SPIRIT_USE_PHOENIX_V3
#include <iostream>
#include <boost/fusion/include/at_c.hpp>
#include <boost/spirit/include/qi.hpp>
#include <boost/spirit/include/phoenix.hpp>
#include <string>
#include <vector>
namespace qi = boost::spirit::qi;
namespace phx = boost::phoenix;
enum LineItems {
SERVICENAME,
POLYNOMIAL,
MODULE,
DLMUW,
WSU,
TCP,
UDP,
INAIR,
CLIENTS,
// RXPORTDCTRL,
// TXPORTDCTRL,
// RXPORTWCTRL,
// TXPORTWCTRL,
// RXPORTD1,
// TXPORTD1,
// RXPORTD2,
// TXPORTD2,
// RXPORTD3,
// TXPORTD3,
// RXPORTD4,
// TXPORTD4,
// RXPORTW1,
// TXPORTW1,
// RXPORTW2,
// TXPORTW2
};
struct CsvLine {
std::string ServiceName;
std::string Polynomial;
std::string Module;
int DLMUW;
int WSU;
int TCP;
int UDP;
int InAir;
int Clients;
// std::string RxPortDCtrl;
// std::string TxPortDCtrl;
// std::string RxPortWCtrl;
// std::string TxPortWCtrl;
// int RxPortD1;
// int TxPortD1;
// int RxPortD2;
// int TxPortD2;
// int RxPortD3;
// int TxPortD3;
// int RxPortD4;
// int TxPortD4;
// int RxPortW1;
// int TxPortW1;
// int RxPortW2;
// int TxPortW2;
};
using Column = std::string;
using Columns = std::vector<Column>;
using CsvFile = std::vector<CsvLine>;
template<typename It>
struct CsvGrammar: qi::grammar<It, CsvFile(), qi::locals<std::vector<LineItems>>, qi::blank_type> {
CsvGrammar() : CsvGrammar::base_type(start) {
using namespace qi;
static const char colsep = ',';
item.add("ServiceName", SERVICENAME)("Polynomial", POLYNOMIAL)("Module", MODULE)("DLMUW", DLMUW)("WSU", WSU)("TCP", TCP)("UDP", UDP)("InAir", INAIR)("Clients", CLIENTS);
start = qi::omit[ header[_a=_1] ] >> eol >> line(_a) % eol;
// Module was unused
header = (item | omit[column] >> attr(MODULE)) % colsep;
line = (column % colsep) [convert];
column = quoted | *~char_(",\n");
quoted = '"' >> *("\"\"" | ~char_("\"\n")) >> '"';
BOOST_SPIRIT_DEBUG_NODES((header)(column)(quoted));
}
private:
qi::rule<It, std::vector<LineItems>(), qi::blank_type> header;
qi::rule<It, CsvFile(), qi::locals<std::vector<LineItems>>, qi::blank_type> start;
qi::rule<It, CsvLine(std::vector<LineItems> const&), qi::blank_type> line;
qi::rule<It, Column(), qi::blank_type> column;
qi::rule<It, std::string()> quoted;
qi::rule<It, qi::blank_type> empty;
qi::symbols<char, LineItems> item;
struct final {
using Ctx = typename decltype(line)::context_type;
void operator()(Columns const& columns, Ctx &ctx, bool &pass) const {
auto& csvLine = boost::fusion::at_c<0>(ctx.attributes);
auto& positions = boost::fusion::at_c<1>(ctx.attributes);
int i =0;
for (LineItems position : positions) {
switch (position) {
case SERVICENAME:
csvLine.ServiceName = columns[i];
break;
case POLYNOMIAL:
csvLine.Polynomial = columns[i];
break;
case MODULE:
csvLine.Module = columns[i];
break;
case DLMUW:
csvLine.DLMUW = atoi(columns[i].c_str());
break;
case WSU:
csvLine.WSU = atoi(columns[i].c_str());
break;
case TCP:
csvLine.TCP = atoi(columns[i].c_str());
break;
case UDP:
csvLine.UDP = atoi(columns[i].c_str());
break;
case INAIR:
csvLine.InAir = atoi(columns[i].c_str());
break;
case CLIENTS:
csvLine.Clients = atoi(columns[i].c_str());
break;
default:
break;
}
i++;
}
pass = true; // returning false fails the `line` rule
}
} convert;
};
int main() {
const std::string s =
"ServiceName,Polynomial,Module,DLMUW,WSU,TCP,UDP,InAir,Clients\n"
"ALBF,0x82608EDB,nic1,1,0,1,1,1,6\n"
"OmsMIS,0x04C11DB7,cmc,1,0,1,1,1,5\n"
"FMS1,0x82F63B78,proc3,1,0,1,1,1,4\n"
"FMS2,0x82F63B78,proc5,1,0,1,1,1,3";
auto f(begin(s)), l(end(s));
CsvGrammar<std::string::const_iterator> p;
CsvFile parsed;
bool ok = qi::phrase_parse(f, l, p, qi::blank, parsed);
if (ok) {
for (CsvLine line : parsed) {
std::cout
<< '[' << line.ServiceName << ']'
<< '[' << line.Polynomial << ']'
<< '[' << line.Module << ']'
<< '[' << line.DLMUW << ']'
<< '[' << line.WSU << ']'
<< '[' << line.TCP << ']'
<< '[' << line.UDP << ']'
<< '[' << line.InAir << ']'
<< '[' << line.Clients << ']';
std::cout << std::endl;
}
} else {
std::cout << "Parse failed\n";
}
if (f != l)
std::cout << "Remaining unparsed: '" << std::string(f, l) << "'\n";
}
答案 0 :(得分：4)
我很确定这是MSVC中的一个错误。由于某种原因，编译器在decltype上窒息（因为它是语法错误，很可能它们还没有实现它）。这是一个解决方法：
using workaround = decltype(line);
using Ctx = typename workaround::context_type;
This seems like the related bug report。它关闭为deferred ...... :(