Using boost::ref on phoenix::closures using boost::spirit v1

[jsmith]

Another boost::spirit question.

The boost::spirit documentation gives the following example of parametric
parser:

taken from http://www.boost.org/doc/libs/1_33_1/libs/spirit/doc/parametric_parsers.html

char ch = 'A';
char from = 'A';
char to = 'Z';

ch_p(boost::ref(ch))
range_p(boost::ref(from), boost::ref(to))

I'd like to build a parser that parses expressions of the form

A-B

where A and B are non-negative integers and B >= A. So here's
the rule I defined:

   int_range = 
         uint_p[int_range.lower_bound = arg1 ]
      >> '-'
      >> min_limit_d( boost::ref( int_range.lower_bound ) )[ uint_p ]
            [int_range.upper_bound = arg1 ]
   ;

with the following declarations:

struct int_range_closure : 
    public boost::spirit::closure< int_range_closure, uint32_t, uint32_t >
{
    member1 lower_bound;
    member2 upper_bound;
};

// and the rule is declared as:
boost::spirit::rule<ScannerT, int_range_closure::context_t> int_range;

But the rule does not compile; it complains because of use of
closure member.

Furthermore, I do not want to leave it up to the semantic actions
to check B >= A (for various reasons which will ultimately lead me
to posting new questions).

Ideas of why this doesn't work or how to make it work?