rules related question

[varnie]

good day, spirit developers. i have a simple question about rules.
suppose we have two rules:

qi::rule<Iterator, boost::shared_ptr<Foo>(), ascii::space_type> start;
qi::rule<Iterator, boost::shared_ptr<Foo>(boost::shared_ptr<Bar>, boost::shared_ptr<Fred>), ascii::space_type> test_rule;

why "start %= test_rule" will be wrong and how to write such thing correctly? thanks a lot.

[Hartmut Kaiser]

> good day, spirit developers. i have a simple question about rules.
> suppose we have two rules:
>
> qi::rule<Iterator, boost::shared_ptr<Foo>(), ascii::space_type> start;
> qi::rule<Iterator, boost::shared_ptr<Foo>(boost::shared_ptr<Bar>,
> boost::shared_ptr<Fred>), ascii::space_type> test_rule;
>
> why "start %= test_rule" will be wrong and how to write such thing
> correctly? thanks a lot.

A attribute of 'shared_ptr<Foo>(shared_ptr<Bar>,shared_ptr<Fred>)' tells me
that you need to invoke the rule 'test_rule' while supplying two inherited
attributes, you're not doing that in your example.

What do you want to achieve?

Regards Hartmut

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[varnie]

thanks for such quick response.
just for learning i want to parse simplified functions, such as: "void foo(int i)" without real body.
here is my rules:
//////////////////////
qi::rule<Iterator, shared_ptr<func_impl_treenode>(shared_ptr<func_head_treenode>, shared_ptr<func_body_treenode>), ascii::space_type> func_impl;
qi::rule<Iterator, std::vector<func_param_treenode>(), ascii::space_type> func_params_list;
qi::rule<Iterator, shared_ptr<func_head_treenode>(), spirit::locals<int, std::string, std::vector< func_param_treenode> >, ascii::space_type> func_head;
qi::rule<Iterator, shared_ptr<func_body_treenode>(), ascii::space_type> func_body;
qi::rule<Iterator, func_param_treenode(), ascii::space_type> func_param;              
qi::rule<Iterator, std::string(), ascii::space_type> ident;
qi::rule<Iterator, shared_ptr<func_impl_treenode>(), ascii::space_type> start;

//////////////////////
//here is the symbol tables used for keywords:

struct func_types_keywords : qi::symbols<char, int> {
    func_types_keywords() {
        add
        ("void", 1)
        ("string", 2)
        ("float", 3)
        ("int", 4)
        ("bool", 5)
        ;
    }
} func_types_keywords_;

struct var_types_keywords : qi::symbols<char, int> {
    var_types_keywords() {
        add
        ("string", 2)
        ("float", 3)
        ("int", 4)
        ("bool", 5)
        ;
    }
} var_types_keywords_;

//////////////////////
//assignments

ident = %raw[lexeme[((alpha | char_('_')) >> *(alnum | char_('_'))) - var_types_keywords_]];
func_param %= var_types_keywords >> ident;
func_params_list %= func_param % ',';
func_head =
        func_types_keywords_[_a = _1] >> ascii::space > ident[_b = _1] >>
        char_('(') >>
        func_params_list[_c = _1] >>
        char(')')
        [_val = construct<shared_ptr<func_head_node> >(new_<func_head_node>(_a, _b, _c))];
func_body = eps //suppose it is empty to simplify our example
        [_val = construct<shared_ptr<func_body_node> >(new_<func_body_node>())];
func_impl = (func_head >> func_body)
        [_val = construct<shared_ptr<func_impl_node> >(new_<func_impl_node>(_r1, _r2))]; //use inherited attributes
start %= *func_impl; //the problem is here

//////////////////////
//executing
std::string input;
//...

MyGrammar grammar;
std::vector<shared_ptr<func_impl_node> > parsed_funcs;

bool result = qi::phrase_parse(input.begin(), input.end(), grammar, ascii::space, parsed_funcs);
//////////////////////

guess my goal is pretty clear (even without the completely MyGrammar source and nodes classes used above). i can post them if there's a need.

thank you for your time. i appreciate it.