Spirit Qi : rule for char [5] - c++

Question

I have the following structure
struct MyStruct
{
char CODE;
char NAME[5];
};
I make it a fusion struct
BOOST_FUSION_ADAPT_STRUCT
(
MyStruct,
(char, MARKET_CODE)
(char, NAME[5])
)
My grammar is implemented as follow:
MyStruct_parser() : ticker_parser::base_type(start)
{
using qi::lexeme;
using ascii::char_;
a_word %= lexeme[+(char_)];
start %= a_word >> a_word;
}
qi::rule<Iterator, std::string(), ascii::space_type> quoted_string;
qi::rule<Iterator, Ticker(), ascii::space_type> start;
Unfortunately it does not compile.
Now I use std::string instead of char[5] I have no problem.
Can you please tell me how to tell Spirit to read char[5]?
Thank you

Answer 1

You can supply custom attribute transformations using boost::spirit::traits::transform_attribute<>:
See it Live On Coliru or indeed Live for C++03
#include <boost/spirit/include/qi.hpp>
#include <boost/array.hpp>
namespace qi = boost::spirit::qi;
typedef char name_t[5];
// typedef boost::array<char, 5> name_t;
struct MyStruct {
char code;
name_t name;
};
namespace boost { namespace spirit { namespace traits {
template <>
struct transform_attribute<name_t, std::vector<char>, qi::domain> {
typedef std::vector<char> type;
static type pre(name_t&) { return {}; }
static void post(name_t& val, type const& attr) {
static_assert(sizeof(val)==5, "");
assert(attr.size() == sizeof(val));
using boost::begin;
using boost::end;
std::copy(attr.begin(), attr.end(), begin(val));
}
static void fail(name_t&) { }
};
} } }
int main()
{
std::string const input("123456");
using It = std::string::const_iterator;
It f(input.begin()), l(input.end());
MyStruct data;
qi::rule<It, std::vector<char>()> c5 = qi::repeat(5) [ qi::char_ ];
bool ok = qi::parse(f,l, qi::char_ >> c5, data.code, data.name);
if (ok)
{
std::cout << "Parse success: " << data.code << ", '" << std::string(std::begin(data.name), std::end(data.name)) << "'\n";
} else
{
std::cout << "Parse failed\n";
}
if (f!=l)
{
std::cout << "Remaining unparsed: '" << std::string(f,l) << "'\n";
}
}
Prints
Parse success: 1, '23456'
in both the c++11 and c++03 versions