Hi,
I'm not being able to figure out what's wrong with my code. Boost's templates are making me go crazy! I can't make heads or tails out of all this, so I just had to ask.
What's wrong with this?
#include <iostream>
#include <boost/lambda/lambda.hpp>
#include <boost/spirit/include/qi.hpp>
void parsePathTest(const std::string &path)
{
namespace lambda = boost::lambda;
using namespace boost::spirit;
const std::string permitted = "._\\-#@a-zA-Z0-9";
const std::string physicalPermitted = permitted + "/\\\\";
const std::string archivedPermitted = permitted + ":{}";
std::string physical,archived;
// avoids non-const reference to rvalue
std::string::const_iterator begin = path.begin(),end = path.end();
// splits a string like "some/nice-path/while_checking:permitted#symbols.bin"
// as physical = "some/nice-path/while_checking"
// and archived = "permitted#symbols.bin" (if this portion exists)
// I could barely find out the type for this expression
auto expr
= ( +char_(physicalPermitted) ) [lambda::var(physical) = lambda::_1]
>> -(
':'
>> (
+char_(archivedPermitted) [lambda::var(archived) = lambda::_1]
)
)
;
// the error occurs in a template instantiated from here
qi::parse(begin,end,expr);
std::cout << physical << '\n' << archived << '\n';
}
The number of errors is immense; I would suggest people who want to help compiling this on their on (trust me, pasting here is unpractical). I am using the latest TDM-GCC version (GCC 4.4.1) and Boost version 1.39.00.
As a bonus, I would like to ask another two things: whether C++0x's new static_assert functionality will help Boost in this sense, and whether the implementation I've quoted above is a good idea, or if I should use Boost's String Algorithms library. Would the latter likely give a much better performance?
Thanks.
-- edit
The following very minimal sample fails at first with the exact same error as the code above.
#include <iostream>
#include <boost/spirit/include/qi.hpp>
int main()
{
using namespace boost::spirit;
std::string str = "sample";
std::string::const_iterator begin(str.begin()), end(str.end());
auto expr
= ( +char_("a-zA-Z") )
;
// the error occurs in a template instantiated from here
if (qi::parse(begin,end,expr))
{
std::cout << "[+] Parsed!\n";
}
else
{
std::cout << "[-] Parsing failed.\n";
}
return 0;
}
-- edit 2
I still don't know why it didn't work in my old version of Boost (1.39), but upgrading to Boost 1.42 solved the problem. The following code compiles and runs perfectly with Boost 1.42:
#include <iostream>
#include <boost/spirit/include/qi.hpp>
int main()
{
using namespace boost::spirit;
std::string str = "sample";
std::string::const_iterator begin(str.begin()), end(str.end());
auto expr
= ( +qi::char_("a-zA-Z") ) // notice this line; char_ is not part of
// boost::spirit anymore (or maybe I didn't
// include the right headers, but, regardless,
// khaiser said I should use qi::char_, so here
// it goes)
;
// the error occurs in a template instantiated from here
if (qi::parse(begin,end,expr))
{
std::cout << "[+] Parsed!\n";
}
else
{
std::cout << "[-] Parsing failed.\n";
}
return 0;
}
Thanks for the tips, hkaiser.