[Boost-users] changing variant type in a visitor

From: james.jones_at_[hidden]
Date: 2005-06-16 14:55:07

Is it possible to change a variant's type within a visitor function? What I'd like to do is something like this:

typedef boost::make_recursive_variant<
    int,
    std::string,
    std::vector<boost::recursive_variant_> >::type   json_t;

Then I'd like to be able to write something like this:

class vector_assign : public boost::static_visitor<json_t&>
{
public:
    vector_assign(int key, const json_t& value);
    json_t& operator()(int&);
    json_t& operator()(std::string&);
    json_t& operator()(vector_t&);
private:
    int key;
    json_t& value;
};

json_t&
vector_assign::operator(vector_t& v)
{
    // the canonical case - we assign a value to a slot in the vector
    if(key>=v.size())
        v.reserve(key);
    v[key] = value;
    return v;
}

json_t&
map_assign::operator(int& i)
{
    // here we want to discard the int value and convert the variant into a new vector with a single value - but how?
}

Thanks,
-
James Jones             Administrative Data Mgmt.
(v)732-510-1806         375 Raritan Center Pkwy, Suite A
(f)732-510-1855         Edison, NJ 08837