From: Pat Maddox <pergesu@...>
Date: 2006-11-25T20:08:02+09:00
Subject: Calling methods from within singleton class

I'd like some clarification on the following simple examples.

class Foo
 self
end             # Foo

class << Foo
 self
end             # #<Class:Foo>

No surprise there.  In the first case I'm defining the class and
returning self, which of course is the class, and in the second it's
the singleton class.

class << Foo
 def foo
   "foo"
 end
end

Now I can call Foo.foo as expected.  It could have just as easily been
def Foo.foo
 "foo"
end

However, I can't do
class << Foo
 foo
end

to call it.  It results in "NameError: undefined local variable or
method `foo' for #<Class:Foo>".  What's the difference?

Pat