From: Bill Kelly <billk@...>
Date: 2009-11-12T05:47:28+09:00
Subject: Re: Separate code space/sandbox?


From: "Patrik Sundberg" <patrik.sundberg@gmail.com>
>
> I'm interested in figuring out a way to get a separate scope. I do not
> need any other traditional sandbox features, i.e. any code goes, I
> just want code evaluated in the scope to no affect the parent scope
> (at all). Example illustrating what I am after:
> 
> a = 10
> SeparatedScope.new do
> a = a + 1
> p a
> end
> p a
> 
> yielding:
> 11
> 10
> 
> I'd like it to have the same initialization/separation also for
> instance variables and even global variables if possible.

This isn't very pretty, but...

class SeparatedScope
  def initialize(code)
    eval(code)
  end
end

a = 10
SeparatedScope.new %{
 a = 11
 p a
}
p a

....

Note there's no access to outer scope variables at all in
this case, thus the inner "a = 11" instead of "a = a + 1".


:(


Regards,

Bill