From: Tim Olsen <tolsen718@...>
Date: 2007-05-30T00:22:14+09:00
Subject: modules including other modules

Hello,

It appears that including module A inside another module B can cause
problems for classes that have already included A.  What seems to
happen is that a class can only see the methods from module B if that
class include module A before module A includes module B.

For example,

module A

  def a
    puts "a"
  end

end

module B

  def b
    puts "b"
  end

end

class C

  include B

  def c
    puts "c"
  end

end

module B

  include A

  def b2
    puts "b2"
  end
end


C.new.c
C.new.b
C.new.b2
C.new.a

produces

tolsen@neurofunk:~/svn/limeade$ /var/tmp/tst.rb
c
b
b2
/var/tmp/tst.rb:42: undefined method `a' for #<C:0x2ac204fe7180> (NoMethodError)

Notice I can define b2() after C has already included B but including
A into B does nothing for C.

Any idea what's going on here?

Thanks,
Tim