From: "Mauricio Fernández" <batsman.geo@...>
Date: 2003-01-23T16:47:33+09:00
Subject: Re: accessors for module instance vars

On Thu, Jan 23, 2003 at 01:01:26PM +0900, Gavin Sinclair wrote:
> On Thursday, January 23, 2003, 4:08:49 AM, Mauricio wrote:
> 
> > I meant that
> > batsman@tux-chan:/tmp$ cat c.rb
> > class A; end
> > class B < A; end;
> > p (B < A)
> > p (B.class < A.class)
> > batsman@tux-chan:/tmp$ ruby c.rb
> > true
> > false
> 
> > as both are of class Class. If there was an automatic relationship
> > between the classes of the classes, my example wouldn't work.
> 
> 
>    >> class A; end
>    => nil
>    >> A < (class << A; self; end)
>    => false
>    >> A > (class << A; self; end)
>    => false
>    >> A <=> (class << A; self; end)
>    => 1
> 
> Can anyone tell me what to make of that?  I thought that the singleton
> of a class inherited from the class.  The operation of "super" within
> a singleton implies that.

class A; def a; "A#A"; end; end
    ==>nil
class << A; def a; "A.a"; super; end; end
    ==>nil
A.a
NameError: super: no superclass method `a'
        from (irb):7:in `a'
        from (irb):8

However
class A; class << self; def a; p "A.a"; end; end; end
    ==>nil
class B < A; class << self; def a; p "B.a"; super; end; end; end
    ==>nil
A.a
"A.a"
    ==>nil
B.a
"B.a"
"A.a"
    ==>nil 

Take a look at the Pickaxe, figure 19.2, p. 244.
The singleton doesn't inherit from the class; if it did, all instance
methods would become class methods too!

As for the starship operator... it cannot return anything meaningful,
can it? I mean we cannot assume that 
 A <=> B     == 1      => A > B

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