From: michele <michelemendel@...>
Date: 2006-10-25T01:10:15+09:00
Subject: Re: What's the difference between send and instance_eval?


So there is no need for "send"?

Thanks


On Oct 24, 12:54 am, "Tim Pease" <tim.pe...@gmail.com> wrote:
> On 10/23/06, michele <michelemen...@gmail.com> wrote:
>
> > What's the difference between send and instance_eval (except the
> > obvious syntax)?
>
> > I've been trying to figure out why Ruby has them both. It seems you can
> > use them intechangeably, at least in the cases I've found and tested
> > (so the question is if there is a case where can't change one for the
> > other).
>
> > Sorry if this has been answered already. I really tried to find the
> > answers in my Ruby and Rails books and on the Internet before posting
> > the question here.send can only be used to execute existing methods on objects.
>
> instance_eval allows you to do much more -- i.e. adding instance
> variables, tinkering with private methods, etc
>
> ary = %w( 1 2 3 4 )
>
> ary.send :length               #=> 4
>
> ary.instance_eval do
>   @length = self.length
> end
>
> ary.instance_variable_get :@length        #=> 4
>
> It's a dumb example, but it should convery the differences.
> 
> Blessings,
> TwP