From: dblack@...
Date: 2006-10-26T12:29:48+09:00
Subject: Re: Pass block instead of here document?

Hi --

On Thu, 26 Oct 2006, Daniel N wrote:

> My understanding of blocks is at best still very shakey, but is there a
> reason in all these that something like
>
> def tell
> yield self
> end
>
> would not have the desired effect.
>
> Then with appropriate method missings etc you could call whatever you like
> in the block.  If the drink and eat methods are already defined in the
> object, they would be called as appropriate.
>
> so to use it.
>
> obj = Foo.new
> obj.tell do
> eat 'burger', 'fries'
> drink 'beer'
> end
>
> Is there a reason that this would not have the same effect as the
> instance_eval methods?

Yes: instance_eval temporarily changes "self", and that means that
bareword method calls like eat and drink will be directed to the Foo
object.  Otherwise, it's just like doing:

   eat

in the middle of a program where you haven't defined an eat method.


David

-- 
                   David A. Black | dblack@wobblini.net
Author of "Ruby for Rails"   [1] | Ruby/Rails training & consultancy [3]
DABlog (DAB's Weblog)        [2] | Co-director, Ruby Central, Inc.   [4]
[1] http://www.manning.com/black | [3] http://www.rubypowerandlight.com
[2] http://dablog.rubypal.com    | [4] http://www.rubycentral.org