From: Adam Prescott <adam@...>
Date: 2011-05-28T00:57:29+09:00
Subject: Re: Method that mutates object

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On 26 May 2011 22:40, "Gary Wright" <gwtmp01@mac.com> wrote:
>
> There are a variety of ways for a Ruby method to gain access to variable
bindings that are out of the direct scope of the method but it is generally
considered bad form for a method to alter variable bindings outside its
scope.  Nevertheless, here is one way to do it:
>
> class Integer
>  def assign(name, value, binding_object)
>    eval "#{name} = #{value}", binding_object
>  end
> end
>
> >> x = 5                     #=> 5
> >> x.assign('x', 7, binding) #=> 7
> >> x                         #=> 7
>
> This sort of use of eval and binding is *not* at all common and probably
only comes into play with various debugging or programming tools rather than
in the normal course of writing Ruby programs.

Not to needlessly self-promote or anything, but I recently wrote about
variables and bindings, so perhaps this is informative:

http://aprescott.com/posts/variables-closures-and-scope

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