Rails edge revision 8056 introduces some great new reader/writer/accessor methods:

• superclass_delegating_reader
• superclass_delegating_writer
• superclass_delegating_accessor

This is best explained with an example:

class Foo
  superclass_delegating_accessor :name
end
class Bar < Foo ; end
class Baz < Foo ; end

Foo.name = "Mr. T"          # => "Mr. T"
Foo.name                    # => "Mr. T"
Bar.name                    # => "Mr. T"
Baz.name                    # => "Mr. T"

Bar.name = "Junkyard Dawg"  # => "Junkyard Dawg"
Foo.name                    # => "Mr. T"
Bar.name                    # => "Junkyard Dawg"
Baz.name                    # => "Mr. T"

Foo.name = "Million $$ Man" # => "Million $$ Man"
Foo.name                    # => "Million $$ Man"
Bar.name                    # => "Junkyard Dawg"
Baz.name                    # => "Million $$ Man"

There are two reasons why this rocks:

• you can independently override something on a subclass without screwing up the the value for the inheritance hierarchy (which is the problem with cattr_accessor/reader/writer methods).

• you can update the superclass’s value and the subclasses which don’t set their specify their own value will receive the update (which is the problem with class_inheritable_accessor/reader/writer methods).