Joel de Guzman wrote:

Joel de Guzman wrote:

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sm4 wrote:

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Oops - seems formatting got in the way.

Hope this is better:

Ooops, I missed your reply. Its better to post spirit related questions to spirit's mailing list. I'm re-posting this there.

Ok, this looks like a bug in handling aliases of the form:

r1 %= r2;

where r1 and r2 are rules with the same type. A quick workaround is to copy the rhs rule:

r1 %= r2.copy();

Eric, It seems to be a problem with Spirit2's usage of proto extends. Here's what's happening: 1) Rule uses proto::extends 2) Rule implements operator %= On expressions: r %= some-expression; The rule's operator%= kicks in. However, on expressions: r %= r2; // r and r2 has the same type Then proto %= kicks in leaving it as a no-op. Nothing happens. Hence, the rhs is never "auto-assigned" to the lhs. I'm not sure how to deal with this. Do you have a hint? I place the original test code here. Tracing the code, the first %= works as expected while the second and third becomes no-ops calling proto operator %=.

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#include <boost/config/warning_disable.hpp> #include <boost/spirit/include/qi.hpp> #include <boost/spirit/include/phoenix_core.hpp> #include <boost/spirit/include/phoenix_operator.hpp> #include <boost/spirit/include/phoenix_fusion.hpp> #include <boost/fusion/include/adapt_struct.hpp> #include <boost/fusion/include/adapt_struct.hpp>

#include <iostream> #include <string>

using namespace boost::spirit; using namespace boost::spirit::qi; using namespace boost::spirit::ascii; using namespace boost::spirit::arg_names;

namespace phoenix = boost::phoenix;

using phoenix::at_c;

struct key_val { std::string key; std::string value; };

BOOST_FUSION_ADAPT_STRUCT( key_val, (std::string, key) (std::string, value) )

template <typename Iterator> struct my_grammar : grammar<Iterator, key_val(), space_type> { my_grammar() : my_grammar::base_type(start) { quoted_string %= lexeme['"' >> +(char_ - '"') >> '"']; key %= quoted_string; value %= quoted_string;

start = key [at_c<0>(_val) = _1] >> ':' >> value [at_c<1>(_val) = _1] ; }

rule<Iterator, std::string(), space_type> key; rule<Iterator, std::string(), space_type> quoted_string; rule<Iterator, std::string(), space_type> value;

rule<Iterator, key_val(), space_type> start;

};

int main() { typedef std::string::const_iterator citerator; std::string str = "\"x\": \"25\" ";

citerator iter = str.begin(); citerator end = str.end();

my_grammar<citerator> my_parser; key_val kv; phrase_parse(iter, end, my_parser, kv, space); // ASSERTs

return 0; }

----------------------------------------------------------------------------------------- Regards, -- Joel de Guzman http://www.boostpro.com http://spirit.sf.net