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require 'active_support/core_ext/kernel/singleton_class'
require 'active_support/core_ext/module/remove_method'
require 'active_support/core_ext/module/deprecation'
class Class
def superclass_delegating_accessor(name, options = {})
# Create private _name and _name= methods that can still be used if the public
# methods are overridden.
_superclass_delegating_accessor("_#{name}", options)
# Generate the public methods name, name=, and name?.
# These methods dispatch to the private _name, and _name= methods, making them
# overridable.
singleton_class.send(:define_method, name) { send("_#{name}") }
singleton_class.send(:define_method, "#{name}?") { !!send("_#{name}") }
singleton_class.send(:define_method, "#{name}=") { |value| send("_#{name}=", value) }
# If an instance_reader is needed, generate public instance methods name and name?.
if options[:instance_reader] != false
define_method(name) { send("_#{name}") }
define_method("#{name}?") { !!send("#{name}") }
end
end
deprecate superclass_delegating_accessor: :class_attribute
private
# Take the object being set and store it in a method. This gives us automatic
# inheritance behavior, without having to store the object in an instance
# variable and look up the superclass chain manually.
def _stash_object_in_method(object, method, instance_reader = true)
singleton_class.remove_possible_method(method)
singleton_class.send(:define_method, method) { object }
remove_possible_method(method)
define_method(method) { object } if instance_reader
end
def _superclass_delegating_accessor(name, options = {})
singleton_class.send(:define_method, "#{name}=") do |value|
_stash_object_in_method(value, name, options[:instance_reader] != false)
end
send("#{name}=", nil)
end
end
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