[Boost-users] retrieve data using associative property maps with boost::bimaps - failed

Subject: [Boost-users] retrieve data using associative property maps with boost::bimaps - failed
From: Aniket Pugaonkar (aniket.pugaonkar_at_[hidden])
Date: 2014-02-10 18:14:43

Hi,

I am facing compilation error in the following code. I do understand why
the error is, but I could not find a good solution. Here is my code and
question explained in detail

*What I want to do:*   I want to store a key- value pair where both key and
its respective values is unique. But After I create a map, I want to use
the VALUE and get the corresponding key. Essentially the best way is a
bimap. So I do the following using associative property maps.

*What I did:*
1. define a bimap  (my_bimap )
2. define associative property map for left view of bimap    (
right_asso_bimap )
3. define associative property map for right view of bimap  (
left_asso_bimap )
4. fill the bimap using *left* view associative property map.
   i.e.  *use boost::put( left_asso_bimap, key, value )*
5. Now using *right* view associative property map, retrieve key for given
value
   i.e. use  *boost::get( right_asso_bimap, value )*

My main motive is to use GET and PUT helper functions for insertion and
retrieval from a bimap.  Use PUT to insert in LEFT BIMAP. and Use GET to
retrieve from RIGHT BIMAP.

I know the error is because of non-const-ness of the iterators because of
which I cannot de-reference using iterators. But what would be the
alternative to this ?
This link here explains how to define parameters for bimap in order for
iterators to be mutable.

http://www.boost.org/doc/libs/1_55_0/libs/bimap/doc/html/boost_bimap/the_tutorial/differences_with_standard_maps.html#boost_bimap.the_tutorial.differences_with_standard_maps.iterator__value_type

*But I get the error below: *

In file included from main.cpp:2:0:

/usr/local/include/boost/property_map/property_map.hpp: In
instantiation of
'boost::associative_property_map<UniquePairAssociativeContainer>::value_type&
boost::associative_property_map<UniquePairAssociativeContainer>::operator[](const
key_type&) const [with UniquePairAssociativeContainer =
boost::bimaps::views::list_map_view<boost::bimaps::relation::member_at::right,
boost::bimaps::detail::bimap_core<int, boost::bimaps::list_of<long
unsigned int>, mpl_::na, mpl_::na, mpl_::na> >
boost::associative_property_map<UniquePairAssociativeContainer>::reference
= const int&; boost::associative_property_map<UniquePairAssociativeContainer>::value_type
= const int; boost::associative_property_map<UniquePairAssociativeContainer>::key_type
= long unsigned int]':

/usr/local/include/boost/property_map/property_map.hpp:357:54:
required from 'Reference boost::get(const
boost::put_get_helper<Reference, PropertyMap>&, const K&) [with
PropertyMap = boost::associative_property_map<boost::bimaps::views::list_map_view<boost::bimaps::relation::member_at::right,
boost::bimaps::detail::bimap_core<int, boost::bimaps::list_of<long
unsigned int>, mpl_::na, mpl_::na, mpl_::na> > > Reference = const
int&; K = int]'

main.cpp:41:35:   required from here

/usr/local/include/boost/property_map/property_map.hpp:502:20: error:
no match for 'operator[]' (operand types are
'boost::associative_property_map<boost::bimaps::views::list_map_view<boost::bimaps::relation::member_at::right,
boost::bimaps::detail::bimap_core<int, boost::bimaps::list_of<long
unsigned int>, mpl_::na, mpl_::na, mpl_::na> > >::C {aka
boost::bimaps::views::list_map_view<boost::bimaps::relation::member_at::right,
boost::bimaps::detail::bimap_core<int, boost::bimaps::list_of<long
unsigned int>, *mpl_::na, mpl_::na, mpl_::na> >}' and 'const key_type
{aka const long unsigned int}')*

       *return (*m_c)[k];*

                    ^

Here my code. You can also see the code here  on this website link:*
http://coliru.stacked-crooked.com/a/59cbf2c564bf22b2
<http://coliru.stacked-crooked.com/a/59cbf2c564bf22b2>*

#include <boost/bimap.hpp> #include
<boost/property_map/property_map.hpp> #include
<boost/bimap/property_map/set_support.hpp>#include
<boost/bimap/list_of.hpp>#include <iostream>
using namespace boost;
int main() {typedef int vertex_descriptor_t;namespace bm =
boost::bimaps;typedef bm::bimap< vertex_descriptor_t,
bm::list_of<size_t> > vd_idx_bimap_t;typedef
boost::associative_property_map<vd_idx_bimap_t::left_map>
Lasso_vd_idx_bimap_t;typedef
boost::associative_property_map<vd_idx_bimap_t::right_map>
Rasso_vd_idx_bimap_t;
// define bimap and assoc prop map for itvd_idx_bimap_t
my_bimap;Lasso_vd_idx_bimap_t  Lmy_asso_bimap(my_bimap.left
);Rasso_vd_idx_bimap_t  Rmy_asso_bimap(my_bimap.right);
typedef typename vd_idx_bimap_t::value_type value_type;
my_bimap.insert( value_type( 1, 100 ) );
my_bimap.insert( value_type( 2, 200 ) );
int z = 1;
std::cout << "value = " << get ( my_bimap.left, z ) << std::endl;
// prints correctly value = 100
// use left asso bimap for inserting to bimap
boost::put( Lmy_asso_bimap, 3, 300 );   // correct
// print bimap using *left view*for(auto t = my_bimap.left.begin(); t
!= my_bimap.left.end(); ++t)
    std::cout << t->first << " " << t->second <<  "\n";
int y = 2;*z **= boost::get( Lmy_asso_bimap, y  );   // CORRECT OUTPUT
for left view *
std::cout << "value = " << z << std::endl;
// Use right asso bimap to get key based on supplied value
y = 100;*z = boost::get( Rmy_asso_bimap, y );*    *// -->> ERROR HERE
for right view*
std::cout << "value = " << z << std::endl;
// print map again. (*right view*)for(auto t = my_bimap.right.begin();
t != my_bimap.right.end(); ++t)
    std::cout << t->first << " " << t->second <<  "\n";
}

Please let me know whether this is a potential bug, or the code semantics
is incorrect. Or the current library cannot support this. ?

Regards,
Aniket Pugaonkar

-- 
Thanks and regards,
Aniket Pugaonkar