Re: [Boost-users] [bind] How do I....?

Subject: Re: [Boost-users] [bind] How do I....?
From: Robert Jones (robertgbjones_at_[hidden])
Date: 2009-08-18 05:58:27

2009/8/18 Björn Karlsson <Bjorn.Karlsson_at_[hidden]>

> Hello Rob,
>
> > Subject: [Boost-users] [bind] How do I....?
> >
> > Use bind to call a free function on a vector of shared_ptrs?
> >
> > struct A { };
> > void f(const A&);
> > std::vector<boost::shared_ptr<A> > v;
> >
> > for_each(v.begin(), v.end(), boost::bind(f, ???? ) );
> >
> > what goes where ???? is?
> >
>
> You have two options if you want to use binders:
>
> 1) Use Boost.Bind with nested binds, binding operator* of shared_ptr in the
> inner bind.
>
>  for_each(vec.begin(), vec.end(), boost::bind(&foo,
> boost::bind(&boost::shared_ptr<A>::operator*, _1)));

This was about the best I could think of too, and is, I think, what I'll do.

>
> 2) Use Boost.Lambda's bind() and dereference the placeholder directly in
> the bind expression.
>
>  for_each(vec.begin(), vec.end(), bind(&foo, *_1));

Much as I like Lambda for virgin code, in my work code base there's a very
visible inclusion
of Boost.Bind, with placeholders in the global namespace. I've concluded
that the pain of clashing
placeholders just isn't worth it, so I steer clear of Lambda now.

Thanks Bjorn.

 - Rob.