Re: [Boost-users] filter_iterator and bind

Nico Galoppo writes:

I'm having trouble getting make_filter_iterator and bind to work together nicely:

------------------------------------------------------------------------------- boost::function is_constraint; is_constraint = boost::bind(&node_type::IsConstraint, _1);

boost::make_filter_iterator(is_constraint, ab.begin(), ab.end()); // ERROR: does not compile boost::make_filter_iterator(boost::bind(&node_type::IsConstraint, _1), ab.begin(), ab.end()); // compiles -------------------------------------------------------------------------------

Note that ab.begin()/ab.end() return iterators to containers of shared pointers. See below for compiler errors.

It's actually not bind, but function. Bind contains magic that treats shared_ptr<T> and T& the same way, but for function to take advantage of that magic, you need to make sure its argument type is shared_ptr<T>, not T&: boost::function)> is_constraint = boost::bind(&node_type::IsConstraint, _1); boost::make_filter_iterator(is_constraint, ab.begin(), ab.end()); The hint is right here:

Reason: cannot convert from 'Hybrid::Graph::const_node_ptr' to 'const node_type' with [ node_traits=ArticulatedModelNodeTraits<MyTypes> ]

HTH, -- Dave Abrahams Boost Consulting www.boost-consulting.com