From: Kirk Haines <khaines@...>
Date: 2004-04-21T23:33:02+09:00
Subject: Re: binding - how to get current script?

On Wed, 21 Apr 2004, Kristof Bastiaensen wrote:

> There is :-)
> You can use Kernel#binding to get the current binding,
> and pass it to eval:
> 
> irb(main):001:0> eval("name = 'Alice'", binding())
> => "Alice"
> irb(main):002:0> name
> => "Alice"

Try it in a program instead of in irb.  That fails.

enigodev % cat t.rb
#!/usr/bin/ruby

eval('name = "alice"',binding)
puts name
enigodev % ./t.rb
./t.rb:4: undefined local variable or method `name' for main:Object 
(NameError)
enigodev %


If one replaces name with @name, then it works.  There is probably a 
logical explanation for why local variables behave in this way within an 
eval, but I do find it surprising, coming from Perl.


Kirk Haines