[Boost-users] [multi_index] modify problem with composite_key

From: Jeffrey Holle (jeffreyholle_at_[hidden])
Date: 2007-09-24 17:07:35

I am having problems using the modify method with my composite_key.
Here is my multi_index container definition:
   typedef multi_index_container<
       entry,
       indexed_by<
         ordered_unique<member<entry,DataVertex,&entry::m_vertex> >,
         ordered_non_unique<
           composite_key<
             entry,
             member<entry,int,&entry::m_y>,
             member<entry,int,&entry::m_x>
           >
         >
       >
     > C;

C m_c;
namespace ll=boost::lambda;

typedef nth_index<C,1>::type XYINDEX;

I have a XYINDEX::iterator that is defined using the equal_range method 
of an XYINDEX order.  Now I wish to modify the m_x attribute that this 
iterator points to so I attempt to write:

inline void
Positioner::updateX(XYIterator iter,int x)
{
   m_c.modify(iter,(&ll::_1)->*&Positioner::entry::m_x=x);
}

I get this compiler error:

positioner.h:77: error: no matching function for call to 
'boost::multi_index::multi_index_container<Positioner::entry, 
boost::multi_index::indexed_by<boost::multi_index::ordered_unique<boost::multi_index::member<Positioner::entry, 
unsigned int, &Positioner::entry::m_vertex>, mpl_::na, mpl_::na>, 
boost::multi_index::ordered_non_unique<boost::multi_index::composite_key<Positioner::entry, 
boost::multi_index::member<Positioner::entry, int, 
&Positioner::entry::m_y>, boost::multi_index::member<Positioner::entry, 
int, &Positioner::entry::m_x>, boost::tuples::null_type, 
boost::tuples::null_type, boost::tuples::null_type, 
boost::tuples::null_type, boost::tuples::null_type, 
boost::tuples::null_type, boost::tuples::null_type, 
boost::tuples::null_type>, mpl_::na, mpl_::na>, mpl_::na, mpl_::na, 
mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, 
mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, 
mpl_::na, mpl_::na>, std::allocator<Positioner::entry> 
 >::modify(boost::multi_index::detail::bidir_node_iterator<boost::multi_index::detail::ordered_index_node<boost::multi_index::detail::index_node_base<Positioner::entry> 
 >, mpl_::na>&, const 
boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::other_action<boost::lambda::assignment_action>, 
boost::tuples::tuple<boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::action<2, 
boost::lambda::other_action<boost::lambda::member_pointer_action> >, 
boost::tuples::tuple<boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::other_action<boost::lambda::addressof_action>, 
boost::tuples::tuple<boost::lambda::lambda_functor<boost::lambda::placeholder<1> 
 >, boost::tuples::null_type, boost::tuples::null_type, 
boost::tuples::null_type, boost::tuples::null_type, 
boost::tuples::null_type, boost::tuples::null_type, 
boost::tuples::null_type, boost::tuples::null_type, 
boost::tuples::null_type> > >, int Positioner::entry::* const, 
boost::tuples::null_type, boost::tuples::null_type, 
boost::tuples::null_type, boost::tuples::null_type, 
boost::tuples::null_type, boost::tuples::null_type, 
boost::tuples::null_type, boost::tuples::null_type> > >, const int, 
boost::tuples::null_type, boost::tuples::null_type, 
boost::tuples::null_type, boost::tuples::null_type, 
boost::tuples::null_type, boost::tuples::null_type, 
boost::tuples::null_type, boost::tuples::null_type> > >)'

I have also tried:

   m_c.modify_key(iter,ll::_1=x);

But this gives me this error:

positioner.h:78: error: no matching function for call to 
'boost::multi_index::multi_index_container<Positioner::entry, 
boost::multi_index::indexed_by<boost::multi_index::ordered_unique<boost::multi_index::member<Positioner::entry, 
unsigned int, &Positioner::entry::m_vertex>, mpl_::na, mpl_::na>, 
boost::multi_index::ordered_non_unique<boost::multi_index::composite_key<Positioner::entry, 
boost::multi_index::member<Positioner::entry, int, 
&Positioner::entry::m_y>, boost::multi_index::member<Positioner::entry, 
int, &Positioner::entry::m_x>, boost::tuples::null_type, 
boost::tuples::null_type, boost::tuples::null_type, 
boost::tuples::null_type, boost::tuples::null_type, 
boost::tuples::null_type, boost::tuples::null_type, 
boost::tuples::null_type>, mpl_::na, mpl_::na>, mpl_::na, mpl_::na, 
mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, 
mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, 
mpl_::na, mpl_::na>, std::allocator<Positioner::entry> 
 >::modify_key(boost::multi_index::detail::bidir_node_iterator<boost::multi_index::detail::ordered_index_node<boost::multi_index::detail::index_node_base<Positioner::entry> 
 >, mpl_::na>&, const 
boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::other_action<boost::lambda::assignment_action>, 
boost::tuples::tuple<boost::lambda::lambda_functor<boost::lambda::placeholder<1> 
 >, const int, boost::tuples::null_type, boost::tuples::null_type, 
boost::tuples::null_type, boost::tuples::null_type, 
boost::tuples::null_type, boost::tuples::null_type, 
boost::tuples::null_type, boost::tuples::null_type> > >)'

While a method like this compiles and works, I would like to be more 
efficent:

inline void
Positioner::updateX(DataVertex vertex,int x)
{
   C::iterator iter=m_c.find(vertex);
   assert(iter!=m_c.end());
   m_c.modify(iter,(&ll::_1)->*&Positioner::entry::m_x=x);
}

Can somebody tell me if what I'm trying to do is possible?
If so, how?