From: "Jesús Gabriel y Galán" <jgabrielygalan@...>
Date: 2008-10-15T23:56:18+09:00
Subject: Re: Lame question about instance variable and attribute

On Wed, Oct 15, 2008 at 4:44 PM, dkmd_nielsen <donn@cmscms.com> wrote:
> Assuming an attribute :field is defined, is there a processing
> difference between using @field and self.field [within the defining
> class?]  Does the ruby interpretter take a different path in yielding
> the value depending how it is referenced?  I haven't notice anything.
> I'm just curious if the interpretter takes extra steps when yielding
> self.field.

@field accessed the instance variable directly, while self.field calls
the method "field" on self. So the paths are completely different:


irb(main):001:0> require 'parse_tree'
=> true
irb(main):027:0> class B
irb(main):028:1> attr_reader :b
irb(main):029:1> def test
irb(main):030:2> @b
irb(main):031:2> end
irb(main):035:1> def test3
irb(main):036:2> self.b
irb(main):037:2> end
irb(main):038:1> end
=> nil
irb(main):039:0> ParseTree.new.parse_tree_for_method(B, :test)
=> [:defn, :test, [:scope, [:block, [:args], [:ivar, :@b]]]]
irb(main):040:0> ParseTree.new.parse_tree_for_method(B, :test3)
=> [:defn, :test3, [:scope, [:block, [:args], [:call, [:self], :b]]]]

Jesus.