Steven,
On 03/09/2011 06:11 AM, Sebastian Theophil wrote:
How can I write a lambda expression with two placeholders, one for
callable object, and one for the function argument, such that supplying the callable object first returns a unary function?
In this case, boost::lambda::_1 by itself does what you want, because
the the
callable object itself is a unary function.
That is true of course, I was trying to solve a slightly more complicated problem though. I have solved the problem finally, although I hoped there was a more elegant solution: struct FCreateBind { typedef boost::_bi::bind_t<bool, Callable, boost::_bi::list2<boost::arg<1>, boost::arg<2> > > result_type; result_type operator()( Callable const& c ) const { return boost::bind<bool>(c, _1); } }; BOOST_AUTO(generate, boost::bind(FCreateBind(), _1)); BOOST_AUTO(fn, generate(Callable()); bool b = fn(Arg()); Of course, in this simple example I could just write BOOST_AUTO(generate, boost::lambda::_1) since Callable itself is the callable object. But I was looking for a way to set the arguments of Callable beforehand so the generated function fn is a nullary function. This solution would let me do this inside FCreateBind. FCreateBind can probably be eliminated as well, but I have not yet figured out how to define the pointer to the overloaded global function boost::bind. Regards Sebastian -- Sebastian Theophil | stheophil@think-cell.com Senior Software Engineer think-cell Software GmbH | Chausseestr. 8/E | 10115 Berlin | Germany http://www.think-cell.com | phone +49 30 666473-10 | US phone +1 800 891 8091 Amtsgericht Berlin-Charlottenburg, HRB 85229 | European Union VAT Id DE813474306 Directors: Dr. Markus Hannebauer, Dr. Arno Schoedl