Hello:
Thanks for the info. I've put in a couple questions below:
On 10/13/2011 2:42 AM, TONGARI wrote:

2011/10/13 Littlefield, Tyler <tyler@tysdomain.com>

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?

See: http://boost-spirit.com/home/articles/doc-addendum/faq/#default

awesome, thanks.

3) Where is menuitem returned?

The synthesized attribute you pass in (if any).

I'm confused here. Would someone mind explaining? I pass in menuitem() to one of the templates, but I'm not sure what that returns.

Is there a way I can push it to a queue since I'll have more?

By either auto attribute propagation or semantic action.

I suggest the former if possible.

I'm not sure how to use the first. The second seems sort of easy, I would just use a function to do that, no? so:
pstart >> item[boost::bind(&Parser::PushMenuItem, this, _1)] >> *(delem >> item[boost::bind(&Parser::PushMenuItem, this, _1)] >> pend;
?

My actual parser will look something like:
pstart >> item >> *(delem >> item) >> pend;

FYI, "item >> *(delem >> item)" can be replaced with "item % delem".

so the former would just be: pstart >> item[...]%delem >> 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?

const std::string &data -> char const* data

std::string::const_ iterator -> char const*

data.begin() -> data

data.end() -> data + length

...and so on

awesome, thanks. I didn't know that I could use that rather than an iterator

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;
}
_______________________________________________
Boost-users mailing list
Boost-users@lists.boost.org
http://lists.boost.org/mailman/listinfo.cgi/boost-users

-- 

Take care,
Ty
Web: http://tds-solutions.net
The Aspen project: a light-weight barebones mud engine
http://code.google.com/p/aspenmud

Sent from my toaster.