[boost] Re: associate_list( Was: [BGL] MutablePropertyGraph questions)

From: Jan Langer (jan_at_[hidden])
Date: 2003-02-03 02:23:48

Vladimir Prus wrote:
>  >>ghost> I think the best approach would be to make this concept 
> explicit, and
>  >>ghost> independent from BGL. Something like
>  >>ghost>
>  >>ghost>    type_indexed_container<
>  >>ghost>      mpl::list<
>  >>ghost>     pair<vertex_name_t, int >,
>  >>ghost>     pair<vertex_distance_t, int> > > c;
>  >>ghost>    c[vertex_name_t()] = 10;
>  >>ghost>     I wonder if something like this already exists... I 
> vaguely recall
>  >>ghost> someone was doing that.
>  >>
>  >>Yes, Emily Winch was working on this, and I thought she was going to
>  >>submit to boost. The following URL has a paper she wrote about this.
>  >>
>  >>http://www.oonumerics.org/tmpw01/schedule.html
>  >
> Personally, I did not really notice your announcements. Some time ago
> I wanted a dynamic type-indexed container, in which you specify the
> required type, and it's either returned, or created. After quite look
> on some email of yours I decided it's something different and stopped 
> reading.

i needed that (or maybe something similar) for the filesystem attributes 
in the sandbox. i tried to make it compatible to the property map 
concept. the output can be used as follows (taken from 
boost-sandbox/libs/filesystem/test/type_pm_test.cpp)

     boost::filesystem::detail::
             type_property_map <char> pm;

     put <int> (pm, 'i');
     put <char> (pm, 'c');

     BOOST_TEST (get <char> (pm) == 'c');
     BOOST_TEST (get <int> (pm) == 'i');
     BOOST_TEST (get <long> (pm) == long ());

it is implemented using Lokis TypeInfo and a std::map <TypeInfo, T> 
where T is the type to store. it is possible to add another layer which 
sets T to boost::any and converts everything in overloaded get/put 
functions. the current attribute cache is (nearly) an example for that.

        boost::fs::cache c (path);
        std::cout << get <size> (c);

jan

-- 
jan langer ... jan_at_[hidden]
"pi ist genau drei"