From: Csaba Henk <csaba@..._for_avoiding_spam.org>
Date: 2005-04-02T22:54:49+09:00
Subject: Re: changing the context in which a block executes

On 2005-03-30, John-Mason P. Shackelford <john-mason@shackelford.org> wrote:
> Greetings.
>
> I'd like to define a method which accepts a block such callers can write:
>
> some_method do
>    op1(arg)
>    op2(arg)
> end
>
> instead of:
>
> some_method do |obj|
>    obj.op1(arg)
>    obj.op2(arg)
> end

[snip]

> My question is, is this the best way to achieve this in Ruby?

The block passed to some_method should be called by instance_eval.

 class Foo
   def printf(x)
     45
   end
   def some_method &b
       instance_eval &b
   end
 end

Foo.new.some_method { printf "a" } # => 45

Csaba