From: pat eyler <pat.eyler@...>
Date: 2006-04-11T00:40:22+09:00
Subject: Re: Quick syntax question

On 4/10/06, Austin Ziegler <halostatue@gmail.com> wrote:
> On 4/10/06, Gregory Seidman <gsslist+ruby@anthropohedron.net> wrote:
> > Consider the following three class definitions:
> >
> > class Foo
> >   def self.bar
> >     @@bar
> >   end
> >   def self.bar=(val)
> >     @@bar = val
> >   end
> > end
> >
> > class Foo
> >   class << self
> >     def bar
> >       @@bar
> >     end
> >     def bar=(val)
> >       @@bar = val
> >     end
> >   end
> > end
> >

[different third class deleted]

> > Am I correct in believing that they are equivalent? If not, how do they
> > differ?
>
> They are not equivalent. The first two are the same, but the third
> will be accessing @bar, not @@bar. (Try it in IRB and you'll see.)
>


Interestingly though, the the sexps representing the AST for the first two
classes are pretty different looking:

[[:class,
  :Example,
  :Object,
  [:defn,
   :example,
   [:scope,
    [:block,
     [:args],
     [:defs, [:self], :bar, [:scope, [:block, [:args], [:cvar, :@@bar]]]],
     [:defs,
      [:self],
      :bar=,
      [:scope, [:block, [:args, :val], [:cvasgn, :@@bar, [:lvar, :val]]]]]]]]]

vs.

[[:class,
  :Example,
  :Object,
  [:defn,
   :example,
   [:scope,
    [:block,
     [:args],
     [:sclass,
      [:self],
      [:scope,
       [:block,
        [:defn, :bar, [:scope, [:block, [:args], [:cvar, :@@bar]]]],
        [:defn,
         :bar=,
         [:scope,
          [:block, [:args, :val], [:cvasgn, :@@bar, [:lvar, :val]]]]]]]]]]]]]



> -austin
> --
> Austin Ziegler * halostatue@gmail.com
>                * Alternate: austin@halostatue.ca
>


--
thanks,
-pate
-------------------------