Extend an existing attribute getter in rails model

Question

Hello all, i have a problem using acts_as_textiled and has_foreign_language plugins together.

TextElement my model in my app

class TextElement < ActiveRecord::Base
    has_foreign_language :value
    acts_as_textiled :value

HasForeignLanguage

def has_foreign_language(*args)
    args.each do |field|
        # Define the Getter
        define_method(field.to_s) do
        .
        .
        .

ActsAsTextiled

def acts_as_textiled(*attributes)
.
.
.
  attributes.each do |attribute|
    define_method(attribute) do |*type|
.
.
.

Both plugins use define_method and which ever way round i call the mixins in TextElement the latter overrides the getter previously defined.

Is there a way to save the existing getter and call that in the newly defined getter? similar to using super if they were inherited.

I have forked these plugins so all is fair game there.

All help appreciated.

Answer 1

You could try having one of the plugins decorate the attributes instead of redefining them. Something like (I'm extending Object here but you can extend whoever needs it):

class Object
  def decorate!(attr)
    method = self.method(attr)
    define_method(attr) do |value|
      result = method.call(value)
      yield(result)
    end
  end
end

So with decorate! in place you might try this in acts_as_textilized

def acts_as_textiled(*attributes)
.
  attributes.each do |attribute|
    self.decorate!(attribute) do |return_value_of_decorated_method|
    # decorate code here

Or something along those lines. Untested, you may have to tweak, but the basic idea is there I think.

Answer 2

Alternatively you can rewrite these two using alias_method_chain.

def some_class_method_that_overrides(*columns)
  columns.each do | c |
    overriden_name = if instance_methods.include?(c)
      alias_method_chain(c.to_sym, "extra")
      "#{c}_with_extra"
    else
      c
    end
    define_method(overriden_name) do ...
    end
  end
end