module ActiveModel::AttributeMethods::ClassMethods

# => 'address_id'
AttributePerson.inheritance_column
AttributePerson.inheritance_column = 'address'
# => "sysid"
AttributePerson.primary_key

Provides you with:

end

end
original_inheritance_column + "_id"
define_attr_method( :inheritance_column ) do
define_attr_method :primary_key, "sysid"

cattr_accessor :inheritance_column
cattr_accessor :primary_key

include ActiveModel::AttributeMethods

class Person

Example:

value.
with "original_". This allows the new method to access the original
The original method will be aliased, with the new name being prefixed

method.
Otherwise, the given block will be used to compute the value of the
specified, the new method will return that value (as a string).
A new (class) method will be created with the given name. If a value is
Defines an "attribute" method (like +inheritance_column+ or +table_name+).

def define_attr_method(name, value=nil, &block)
  sing = singleton_class
  sing.class_eval <<-eorb, __FILE__, __LINE__ + 1
    if method_defined?(:'original_#{name}')
      undef :'original_#{name}'
    end
    alias_method :'original_#{name}', :'#{name}'
  eorb
  if block_given?
    sing.send :define_method, name, &block
  else
    # If we can compile the method name, do it. Otherwise use define_method.
    # This is an important *optimization*, please don't change it. define_method
    # has slower dispatch and consumes more memory.
    if name =~ COMPILABLE_REGEXP
      sing.class_eval <<-RUBY, __FILE__, __LINE__ + 1
        def #{name}; #{value.nil? ? 'nil' : value.to_s.inspect}; end
      RUBY
    else
      value = value.to_s if value
      sing.send(:define_method, name) { value }
    end
  end
end