Re: [Boost-users] [bind] How to dereference _1 in a boost::bindexpression

2 Oct 2008


      Peter Barker wrote:
...
On Thu, Oct 2, 2008 at 3:25 PM, Peter Dimov  wrote:
...
Peter Barker:
...
...
void accept(TheClass& tc)
{
}
int main()
{
std::vector cont;
// Compile error - how to dereference _1 ???
std::for_each(cont.begin(),cont.end(),boost::bind(&accept,_1));
}
How can I dereference _1 so I can use the accept function?
With boost::bind, there's no easy way to dereference _1. You'd need
template<class T> T& deref( T* p ) { return *p; }
std::for_each( cont.begin(), cont.end(),
  boost::bind( accept, boost::bind( deref<TheClass>, _1 ) )
);
Peter,
It's nice to hear the answer from the horses mouth (so to speak)!
IIRC, indirect_iterator takes this approach. The following should work 
as well:

std::for_each( make_indirect_iterator(cont.begin())
              , make_indirect_iterator(cont.end())
              , boost::bind( accept, _1));

Jeff Flinn