[C++-sig] vector_indexing_suite and bool.

[Joel de Guzman]

Prabhu Ramachandran <prabhu at aero.iitm.ernet.in> wrote:
> Hi,
> 
> Thanks for the vector_indexing_suite!  It is really nice and seems to
> work wonderfully!  However, I just ran into one problem with it.  I
> tried wrapping a std::vector<bool> and things don't compile because
> the vector_indexing_suite::get_item(...) returns a reference to the
> bool which the compiler has problems with.  Here is the trivial test
> program and error message that I get with g++-2.95.4 and Boost from
> CVS.
> 
> // --------------------------------------------------
> #include <boost/python.hpp>
> #include <boost/python/suite/indexing/vector_indexing_suite.hpp>
> 
> using namespace boost::python;
> 
> BOOST_PYTHON_MODULE(vec_index)
> {
>     class_< std::vector<bool> > ("VectorBool")
>         .def(vector_indexing_suite< std::vector<bool>, true> ());
> }
> // --------------------------------------------------

[snip errors]

> I made a local copy of the vector_indexing_suite and changed this:
> 
>         static data_type&
>         get_item(Container& container, index_type i)
> to:
> 
>         static data_type
>         get_item(Container& container, index_type i)
> 
> and my test program compiles cleanly.  This is obviously not a fix but
> just to let you know that this is the only problem.

Thanks for trying it out, Prabhu. I'll go and find a solution to
this problem. I think, off the top of my head, that get_item should be:

        static typename mpl::if_<
            is_class<data_type>
          , data_type&
          , data_type
        >::type
        get_item(Container& container, index_type i)

Regards,
-- 
Joel de Guzman
http://www.boost-consulting.com
http://spirit.sf.net