Re: [Boost-users] 2 bind questions

On Tuesday 04 November 2003 08:47 pm, Angus Leeming wrote:

I'm having some problems with bind and wonder if someone might help. [snip code] boost/boost-1.30.2/boost/function/function_template.hpp:117: could not convert `f->boost::_bi::bind_t::operator()(A1&) [with A1 = size_t, R = const Node&, F = boost::_mfi::cmf1, L = boost::_bi::list2 >]((&a0))' to `Node&'

How odd. I would have expected it to be ambiguous at the call to bind, but it takes the const version over the non-const version.

Is there a fix for this or have I hit a brick wall?

Well, you're stuck casting the member function pointer to the right type: boost::function1 get_node = boost::bind((Node& (FEM::*)(FEM::size_type))&FEM::node, boost::ref(fem), _1);

Second question. I'd like to combine these two boost::functions into a single boost::function2 all_in_one = ...; all_in_one(i, val); but I'm getting horribly lost trying to determine the '...'. Is it possible? Any clues?

Ah, the beauty of nesting bind() expressions. Start with the outer call (set_conc), and work your way inward by writing the parameters to it. Here's the final solution (with ugly casting hack): boost::function2 all_in_one = boost::bind(&Node::set_conc, boost::bind((Node& (FEM::*)(FEM::size_type))&FEM::node, boost::ref(fem), _1), _2); Doug