Re: [Spirit-devel] Auto attributes propagation in directives with lazy arguments

[Lee C. <fo...@le...>]

On Fri, Feb 13, 2015 at 7:05 AM, Nikita Kniazev <nok...@gm...> wrote:

> I hit problem with attributes propagation when using semantic actions,
> even with using enforcing operator %=.
> Following test case shows inconsistent in behavior of directives with lazy
> parameters vs normal.
>
> /******************************************************************************/
>
> #include <boost/spirit/include/phoenix_core.hpp>
>
> #include <boost/spirit/include/qi.hpp>
>
>
> namespace qi = boost::spirit::qi;
>
>
> template <typename T>
>
> void test(const T& rule)
>
> {
>
>   const std::string in = "123";
>
>   std::vector<int> out;
>
>
>   std::string::const_iterator iter = in.begin();
>
>   const std::string::const_iterator end = in.end();
>
>
>   const bool r = qi::parse(iter, end, rule, out);
>
>
>   std::cout << out.size() << std::endl;
>
>
>   BOOST_ASSERT(r && iter == end);
>
> }
>
>
> int main()
>
> {
>
>     using qi::int_;
>
>     using qi::_1;
>
>     using boost::phoenix::val;
>
>                                          //       Lazy  Semantic
>
>     test(qi::repeat(1)[int_]);           // OK    No    No
>
>     test(qi::repeat(1)[int_[_1]]);       // OK    No    Yes
>
>     test(qi::repeat(val(1))[int_]);      // OK    Yes   No
>
>     test(qi::repeat(val(1))[int_[_1]]);  // FAIL  Yes   Yes
>
>
>     return 0;
>
> }
>
> /******************************************************************************/
>
>
> I'm not sure, but as for me this is a bug (which interfere me at using my
> own custom directive).
>

The expression int_[_1] creates an integer parser with an attached semantic
action that does nothing, so its not exactly clear to me what you are
trying to do. Did you mean to do a push_back(ref(vector), _1) or something?

Lee