Ruby Language Message Passing Message Passing Through Module Composition
Example
Ruby moves up on ancestors chain of an object. This chain can contain both modules and classes. Same rules about moving up the chain apply to modules as well.
class Example
end
module Prepended
def initialize *args
return super :default if args.empty?
super
end
end
module FirstIncluded
def foo
:first
end
end
module SecondIncluded
def foo
:second
end
end
class SubExample < Example
prepend Prepended
include FirstIncluded
include SecondIncluded
def initialize data = :subexample
puts data
end
end
SubExample.ancestors # => [Prepended, SubExample, SecondIncluded, FirstIncluded, Example, Object, Kernel, BasicObject]
s = SubExample.new # => :default
s.foo # => :second
