From: Dave Thomas <Dave@...>
Date: 2001-10-26T00:34:26+09:00
Subject: [ruby-talk:23306] Re: why the @ s ?

Tobias Reif <tobiasreif@pinkjuice.com> writes:

> I declare 3 variables whose name starts with an @ sign. When I omit any 
> of the three @ signs, the Program doesn't work anymore.
> Why?

Because you're sharing the variables between the top level scope and
methods defined in that scope. Methods don't have access to the local
variables of the surrounding scope:

   a = 10
   def fred
     p a      #=> -:3:in `fred': undefined local variable or method `a'
   end

However, making them instance variables allows them to be shared, as
your whole program runs within the scope of an anonymous Object.

   @a = 10
   def fred
     p @a      # OK
   end


Regards


Dave