From: "David A. Black" <dblack@...>
Date: 2009-04-30T00:43:33+09:00
Subject: Re: Why does attr_accessor in module require 'self.'?

Hi --

Brian Hartin wrote:
> The second and third posts have made it clear for me.  This is necessary
> to allow local variables with the same name as instance variables.  A
> contrasting example from a statically typed language makes this more
> clear (for me):
>
> (Java)
>
> public class Foo
>    private int x;
>
>    public void bar() {
>      int x = 2;  // Very obviously a local variable
>    }
> end
>
> Since Ruby variables are allocated on first use, and Ruby has no
> explicit variable declaration syntax, there would be no way to have a
> local variable 'x' if an instance variable '@x' existed:
>
> class Foo
>    attr_accessor :x
>
>    def bar
>      # If this were the same as self.x = 2, or @x = 2,
>      # it would not be possible to have a local variable 'x'?
>      x = 2
>    end
> end

Remember, though, that

   @x = 2

and

   obj.x = 2  # where obj may or may not be self

have nothing to do with each other. As Florian said, obj.x = 2 is a 
method call (the method being x=).


David

-- 
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