[LRUG] Ruby Cluetrain

[Anthony Green]

I hope James won't mind me posting this Gist he tweeted at the weekend. But
it exemplifies the kind of gaps I have in my Ruby knowledge.
Whilst I understand what individual segments of code are doing I don't
understand what the code as a whole is attempting to do.

Anyone willing to shed some light ?

http://gist.github.com/217001


# I'm creating some classes and modules on the fly, but things aren't
hooking up quite the way I'd hoped.
# Can anyone explain why when an instance of Mod::Sibling tries to call
 
Child.cry, that it

# doesn't call Mod::Child.cry, but instead looks for Behaviour::Child?
 
class Base
  def self.cry
    "#{self.name}.cry called!"
  end
end
 
module Behaviour
  def blame
    puts "I am #{self}, a #{self.class.name}, trying to call Child.cry"
    Child.cry
  end
end
 
child = Class.new(Base)
 
Mod = Module.new
Mod.const_set(:Child, child)
 
child.cry # => "Mod::Child.cry called!"
Mod::Child.cry # => "Mod::Child.cry called!"
child.name # => "Mod::Child"
 
sibling = Class.new(Base)
sibling.class_eval do
  include Behaviour
end
Mod.const_set(:Sibling, sibling)
sibling.name # => "Mod::Sibling"
 
Mod.constants # => ["Child", "Sibling"]
 
sibling = Mod::Sibling.new
sibling.blame # => 
# ~> -:10:in `blame': uninitialized constant Behaviour::Child (NameError)
# ~>  from -:32
# >> I am #<Mod::Sibling:0x1973078>, a Mod::Sibling, trying to call
Child.cry





-- 
Anthony Green
Client Side Developer
Future Media & Technology for BBC Audio & Music Interactive


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