[Boost-users] help with boost::spirit:parsing out a list of menuitems

Subject: [Boost-users] help with boost::spirit:parsing out a list of menuitems
From: Littlefield, Tyler (tyler_at_[hidden])
Date: 2011-10-12 13:13:55

Hello:
I have a client I'm writing, where the server sends data to the client 
to display as a menu in one instance. I wanted to use boost::spirit to 
parse this out. So, here's the code.
I have three questions:
1) What can I do better/differently?
2) When I parse out my menuitem, if there's no flag, can it be set to 0 
by default somehow?
3) Where is menuitem returned? Is there a way I can push it to a queue 
since I'll have more? My actual parser will look something like:
pstart >> item >> *(delem >> item) >> pend;
Here is the code I have currently:
struct menuitem
{
std::string name;
int flag;
int choice;
};

BOOST_FUSION_ADAPT_STRUCT(
                           menuitem,
                           (std::string, name)
                           (int, flag)
                           (int, choice))

                           namespace ascii = boost::spirit::ascii;
namespace qi = boost::spirit::qi;

//I'd like to just take a char* here, since that's my payload. copying 
the char* to a std::string will take extra time, is there a way to do that?
BOOL Menu::Parse(const std::string &data, int length)
{
     std::string::const_iterator it, itEnd;
     it = data.begin();
     itEnd = data.end();

     //we construct a few parsers to make things easier.

     qi::rule<std::string::const_iterator, char, ascii::space_type> 
pstart = qi::char_('[');
     qi::rule<std::string::const_iterator, char, ascii::space_type> pend 
= qi::char_(']');
     qi::rule<std::string::const_iterator, char, ascii::space_type>delem 
= qi::char_('|');
     qi::rule<std::string::const_iterator, menuitem(), 
ascii::space_type>item = qi::char_("a-zA-Z0-9 -.?!$@") >> qi::char_('(') 
 >> -qi::int_ >> qi::char_(':') >> qi::int_ >> qi::char_(')');

     if (!qi::phrase_parse(it, itEnd, pstart >> item >> pend, ascii::space))
     {
         return false;
     }
     return true;
}

-- 
Take care,
Ty
Web: http://tds-solutions.net
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