cascade

# Gives the ability to cascade upward for an attribute in a nested_set
# So, for example, if a project does not have a client specified, it will
# inherit the client of its parent, or further ancestor.
module Cascade
  def self.included(klass)
    klass.extend(ClassMethods)
  end  
              
  module ClassMethods             
    def cascades(*args)
      args.each do |attrib|                  
        if column_names.any?{|n| n==attrib.to_s} 
          p "defining attribute version for #{attrib}"
          class_eval <<-EOM, __FILE__, __LINE__
          def #{attrib}
            p "foo"
            if read_attribute(#{attrib}).blank?
              p "bar1"
              ancestors.reverse.find{|a| !a.read_attribute(#{attrib}).blank? }.read_attribute(#{attrib})
            else       
              p "bar2"
              read_attribute(#{attrib})
            end
          end
          EOM
        else
          p "defining method version for #{attrib}"
          class_eval <<-EOM2, __FILE__, __LINE__
          def #{attrib}_with_cascade
            if #{attrib}_without_cascade.blank?
              ancestors.reverse.find{|a| !a.#{attrib}_without_cascade.blank? }.#{attrib}_without_cascade
            else   
              #{attrib}_without_cascade
            end
          end                                 
          EOM2
          alias_method_chain attrib, :cascade
        end
      end  
    end  
  end
    
end