Hi, 

In message "[ruby-talk:00331] module-class calling"
    on 99/05/22, "Michael Neumann" <neumann / s-direktnet.de> writes:
>Can I call a function of a module from a class-method?
>Following example didn't work! Why?

Another solution is to let `hello' be a module function by
`module_function':

  module A
    def hello
      print "HELLO\n"
    end
    module_function :hello
  end 

  class B
    def call_A
      A.hello
    end
  end

  x = B.new
  x.call_A

Module.html#module_function says, 

	the module functions are the method which is
        also the singleton method of a module (or a class). 

If a module is included the module functions seems not methods but
just functions.  It is because of they are called module *functions*,
I think. In case of calling module functions, preceding module name
(e.g., Math or A) plays like a name space rather than a receiver.  It
is very similar to the case of a constant with scope operator `::'
(e.g, Math::PI) -- in deed, class methods or module functions can be
call with :: (e.g., Math::sin(x)) in Ruby 1.3.x.

hope this helps, 

-- gotoken