Re: [Boost-users] Bind, lambda and how to chain relative function calls

From: Peter Dimov (pdimov_at_[hidden])
Date: 2005-11-24 06:41:05

Kerner, Jacques wrote:
> Hi,
> 
> I would like to create a functor for calling functions in a chain like
> this :
> 
> car.GetRigidBody().GetPosition().GetX()
> 
> What is the best way to do that using bind (and lambda ?)
> 
> The car.GetRigidBody() is easy : bind(&Car::GetRigidBody, &car) , but
> then I am a bit stuck. Note that I don't want to store the result of
> car.GetRigidBody(). I want the final functor to call all the functions
> everytime its operator() is called. So
> 
> 
> bind (
> &Position::GetX,
> &bind (
> &RigidBody::GetPosition,
>                         &bind (
> 
> &Car::GetRigidBody,
>                                     &car
>                                 )()
>                     )()
> )
> 
> would not be acceptable...

Just drop the invocations:

bind (
    &Position::GetX,
    bind (
        &RigidBody::GetPosition,
        bind( &Car::GetRigidBody, &car)
    )
)