Boost spirit 2.x: how to deal with keywords and identifiers?

Hmmm just declare your rule to be: the > operator say that your keyword MUST be followed by an ident //instead of just may (if I understood spirit right the >> operator will //make the parser consider other rules if it fail which might or not be //what you want. Ident_decl = keyword_table_ > ident Expending on your exemple you should have something like this at the end: struct my_keywords : boost::spirit::qi::symbols { my_keywords() { add ("void", TYPE_VOID) ("string", TYPE_STRING) ("float", TYPE_FLOAT) ("int", TYPE_INT) ("bool", TYPE_BOOL) //TODO: add others ; } } keywords_table class ident_decl_node { //this will enable fusion_adapt_struct to access your private members template friend struct boost::fusion::extension::struct_member; int type; std::string ident; }; BOOST_FUSION_ADAPT_STRUCT( ident_decl_node, (int, type) (std::string, ident) ) struct MyErrorHandler { template struct result { typedef void type; }; template void operator()(Iterator first, Iterator last, Iterator error_pos, std::string const& what) const { using boost::phoenix::construct; std::string error_msg = "Error! Expecting "; error_msg += what; // what failed?

Error_msg += " here: \""; error_msg += std::string(error_pos, last); // iterators to error-pos, end error_msg += "\""; //put a breakpoint here if you don't have std::cout for the console or change //this line for something else. Std::cout ScriptNodes; template struct NodeGrammar: public grammar { using boost::spirit::arg_names; //edit1 NodeGrammar: NodeGrammar::base_type(start) { //I had problem if I didn't add the eps rule (which do nothing) so you might //want to leave it start %= ident_decl | some_other_node_decl >> eps; ident_decl %= keyword_table > ident; //I'm not sure if the %= operator will work correctly on this, you might have to do //the push_back manually but I think it should work ident %= rawlexeme((alpha | char_('_')) >> *(alnum | char_('_'))) - keywords_table_; on_error(start, error_handler(_1, _2, _3, _4)); //edit1 } my_keywords keyword_table_; boost::spirit::qi::rule start; boost::spirit::qi::rule ident_decl; boost::spirit::qi::rule ident_decl; boost::spirit::qi::rule ident; boost::phoenix::function error_handler; //edit1 } Also I don't know which version you use but I used the one in boost 1.40 and it seems there is a bug when using operator %= followed by only one argument (the parser would not parse correctly this rule). Ex: ident_decl %= ident do this instead ident_decl %= ident > eps which should be equivalent Hope this helped.

Hmmm just declare your rule to be: //the > operator say that your keyword MUST be followed by an ident //instead of just may (if I understood spirit right the >> operator will //make the parser consider other rules if it fail which might or not be //what you want. Ident_decl = keyword_table_ > ident; Expending on your exemple you should have something like this at the end: struct my_keywords : boost::spirit::qi::symbols { my_keywords() { add ("void", TYPE_VOID) ("string", TYPE_STRING) ("float", TYPE_FLOAT) ("int", TYPE_INT) ("bool", TYPE_BOOL) //TODO: add others ; } } keywords_table_; //... class ident_decl_node { //this will enable fusion_adapt_struct to access your private members template friend struct boost::fusion::extension::struct_member; int type; std::string ident; }; BOOST_FUSION_ADAPT_STRUCT( ident_decl_node, (int, type) (std::string, ident) ) //... struct MyErrorHandler { template struct result { typedef void type; }; template void operator()(Iterator first, Iterator last, Iterator error_pos, std::string const& what) const { using boost::phoenix::construct; std::string error_msg = "Error! Expecting "; error_msg += what; // what failed?

Error_msg += " here: \""; error_msg += std::string(error_pos, last); // iterators to error-pos, end error_msg += "\""; //put a breakpoint here if you don't have std::cout for the console or change //this line for something else. Std::cout ScriptNodes; template struct NodeGrammar: public grammar { using boost::spirit::arg_names; //edit1 NodeGrammar: NodeGrammar::base_type(start) { //I had problem if I didn't add the eps rule (which do nothing) so you might //want to leave it start %= ident_decl | some_other_node_decl >> eps; ident_decl %= keyword_table > ident; //I'm not sure if the %= operator will work correctly on this, you might have to do //the push_back manually but I think it should work ident %= rawlexeme((alpha | char_('_')) >> *(alnum | char_('_'))) - keywords_table_; on_error(start, error_handler(_1, _2, _3, _4)); //edit1 } my_keywords keyword_table_; boost::spirit::qi::rule start; boost::spirit::qi::rule ident_decl; boost::spirit::qi::rule ident_decl; boost::spirit::qi::rule ident; boost::phoenix::function error_handler; //edit1 }; Also I don't know which version you use but I used the one in boost 1.40 and it seems there is a bug when using operator %= followed by only one argument (the parser would not parse correctly this rule). Ex: ident_decl %= ident; do this instead ident_decl %= ident > eps; which should be equivalent.

Hope this helped.

Thanks for try, but it doesn't work for me. I have many errors, such as: error: no matching function for call to 'boost::fusion::vector_data1, Freefoil::Private::ident_decl_node&>::vector_data1(int&)'| boost/fusion/container/vector/detail/vector_n. Hpp – varnie Oct 28 '09 at 13:48 wow!

I've solved it! Your note about adding ">> eps" to the end of rule was a cause of problem! In any case, the rule: start %= ident_decl; compiles fine.

Good, now I have a toy compilable grammar. Thank you! – varnie Oct 28 '09 at 14:11 Hmm weird, >> eps should not do anything.

I had problem at runtime if I didn't had >> eps when working with operator %=. Watch it if your program assert at runtime saying something about intrusive_ptr ptr == NULL. But you don't use the same version as I so I don't know.

Cheers for solving your problem varnie! – n1ckp Oct 28 '09 at 14:30.

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