Hi Ezra.

You've got it wrong. The point is that though a method that is defined
outside of any class becomes automatically part of Object, it can't be
called with exact receiver because the method is *private*.

In other words,

 # foo is private method of Object
def foo
  ..
end

class Bar; end

# This is okay, because I'm calling self.foo and we do not
# need to state self as receiver.
foo

# This is completely wrong. Private method can't be called
# with exact receiver.
Bar.new.foo

Hope this helps.

Sincerely,
Minkoo Seo

On 7/1/06, Ezra Zygmuntowicz <ezmobius@[...].com>  wrote:
> 
> 
>  On Jun 30, 2006, at 7:10 PM, Minkoo Seo wrote:
> 
>  > Hi list.
>  >
>  > I've recently learned that irb and ruby (ruby interpreter) behave
>  > differently often
>  > and that irb is not running on ruby interpreter.
>  >
>  > As an example,
>  >
>  > [mkseo@uranus src]$ irb
>  > irb(main):001:0> def foo
>  > irb(main):002:1>   puts "foo"
>  > irb(main):003:1> end
>  > => nil
>  > irb(main):004:0> class Bar; end
>  > => nil
>  > irb(main):005:0> Bar.new.foo
>  > foo
>  > => nil
>  > irb(main):006:0> quit
>  >
>  > irb let me call foo which is non-sense.
>  >
>  > [mkseo@uranus src]$ cat > test.rb
>  > def foo
>  >  puts "foo"
>  > end
>  > class Bar; end
>  > Bar.new.foo
>  > [mkseo@uranus src]$ ruby test.rb
>  > test.rb:5: private method `foo' called for #<Bar:0x2aaaaab00cc8>
>  > (NoMethodError)
>  > [mkseo@uranus src]$
>  >
>  > Ruby interpreter fails as expected.
>  >
>  > So, here's my question. Why is irb running on its own interpreter(or
>  > simulator or whatever)?
>  >
>  >
>  > Sincerely,
>  > Minkoo Seo
> 
> 
>  When you def a method in irb outside of any class definition it
>  actually gets added to Object i believe. Since the top level of irb
>  outside of any class definitions is essentially running inside of
>  Object. So that is why you can call foo from inside of class Bar
>  since class Bar inherits from Object by default.
> 
>  ez $ irb
>  irb(main):001:0> self.class
>  => Object
> 
> 
> 
>  -Ezra
> 
> 
> 
>