From: Christoph <chr_news@...>
Date: 2002-04-04T23:11:54+09:00
Subject: Re: Mixins vs. Multiple Inheritance


"Jason Voegele" <jason@jvoegele.com> wrote in
....
> So how would the following scenario be any different if Foo and Bar were
> classes instead of modules? (presuming that Ruby had true multiple
> inheritance):

I find it interesting that Ruby's (1.7) default method-search order in
``Mixin''-Graphs coincides with (or is at least ``close to'') the Python
2.2 method-search order in a ``MI''-Graph. However with a bit of work
one can also create a ``Mixin''-Graph with a C++-like method look up
- i.e. Ruby's mixin strategy is in some sense more complex than
``ordinary'' purely class based MI.

/Christoph

-----
# the output of the classical diamond-graph (why isn't this
# called rhombus?) script assuming (1.7) is
# D < L < R < O is python's method-search order
# D < L < O < R is the c++'s method-search order

module O
end

module L
include O
end

module R
include O
end

module D
include R
include L
end


puts "#{D.ancestors.join(' < ')} is python's method-search order"


class Object;
  remove_const :O
  remove_const :L
  remove_const :R
  remove_const :D
end


module O
end
module L
end
module R
end
module D
include R
include O
include L
end

module L
  include O
end

module R
  include O
end

puts "#{D.ancestors.join(' < ')} is the c++'s method-search order"
----