RE: [boost] Lambda/functions

From: Roman Yakovenko (roman.yakovenko_at_[hidden])
Date: 2004-05-13 05:23:34

>best2=bind(&Node::value2,
>             bind( &std::vector<Node>::at,	//Ask for an element
>                  bind(&Node::children,_1),	//Get the vector object
>                  0 )	//Ask for element zero
>              );
> 
> [3]:
> function.cpp: In function `int main(int, char**)':
> function.cpp:69: no matching function for call to 
> `bind(<unknown type>, const
>  
> boost::lambda::lambda_functor<boost::lambda::lambda_functor_ba
> se<boost::lambda::action<2,
>     boost::lambda::function_action<2, 
> boost::lambda::detail::unspecified> >,
>     boost::tuples::tuple<std::vector<Node, 
> std::allocator<Node> > Node::*, const
>     boost::lambda::lambda_functor<boost::lambda::placeholder<1> >,
>     boost::tuples::null_type, boost::tuples::null_type,
>     boost::tuples::null_type, boost::tuples::null_type,
>     boost::tuples::null_type, boost::tuples::null_type,
>     boost::tuples::null_type, boost::tuples::null_type> > >, int)'
> 

It's simple, compiler can't guess which function "at" you try to bind.

See overloading section of lambda documentation. 
Hint: 

typedef std::vector<int> ints;
typedef ints::const_reference ( ints::*ConstAtFunc ) (ints::size_type) const;
Now call bind with ConstAtFunc( at ) as function

Roman