From: Joel VanderWerf <vjoel@...>
Date: 2001-10-08T04:54:52+09:00
Subject: [ruby-talk:22209] Re: Ruby and multiple inheritance

ts wrote:
> 
> >>>>> "P" == Paul Brannan <pbranna@nospam.clemson.edu> writes:
> 
> P>    module Base
> P>      def foo
> P>        puts "Base"
> P>      end
> 
>         module_function :foo
> 
> P>    end
> [...]
> P>      def foo
> P>        super # How can I specify that I want to call Base's foo()?
> 
>           Base.foo
> 
> P>        puts "Derived"
> P>      end
> P>    end
> 
> P>    d = Derived.new
> P>    d.foo
> 
> Guy Decoux

Base#foo called in this way cannot affect the instance vars of Derived.
You can only do that with super or another method, not a
module_function:

module Base
  def foo
    puts "Base"
    @x = 1
  end
  module_function :foo
end

class Derived
  include Base
  
  def foo
    Base.foo
    puts "Derived"
    puts @x
  end
end

d = Derived.new
d.foo

# output:
# Base
# Derived
# nil

def Base.bar
  puts @x
end

Base.bar

# output:
# 1

--
Joel VanderWerf                          California PATH, UC Berkeley
mailto:vjoel@path.berkeley.edu                     Ph. (510) 231-9446
http://www.path.berkeley.edu                       FAX (510) 231-9512