From: Logan Capaldo <logancapaldo@...>
Date: 2006-04-02T06:16:44+09:00
Subject: Re: Dynamic code generation


On Apr 1, 2006, at 12:03 PM, Thiago Arrais wrote:

> I have been trying to do some simple dynamic code generation in Ruby.
> What I am specifically trying is to redefine a class level method on
> the subclasses. I know I may achieve that by using a simple def, but I
> would like come up with a simpler syntax, something like this:
>
> ----
> class Parent
>     def self.redefinable_method
>         return "This is the default string returned when the method
> isn't redefined"
>     end
>
>     def redefinable_method
>         return self.class.redefinable_method
>     end
> end
>
> class FirstChild < Parent
>     redefine "This is the custom string for the FirstChild class"
> end
>
> class SecondChild < Parent; end
>
> fst = FirstChild.new
> fst.redefinable_method => "This is the custom string for the  
> FirstChild class"
>
> snd = SecondChild.new
> snd.redefinable_method => "This is the default string returned when
> the method isn't redefined"
> ----
>
> In this example you can see two points: (a) I am a total newbie, (b)
> the method 'redefine' should be defined on the parent class, but I
> don't have a clue on how it should be written. I have taken a look at
> ActiveRecord's associations, but it seems like overkill to use the
> exact same approach.
>
> Two questions:
>
> Is it possible to do that?
> Can the client code (child classes) be made any simpler/shorter?
>
> Cheers,
>
> Thiago Arrais
>

This seems to be a solution looking for a problem
class Parent
     def redefinable_method
           "This is the default string returned when the method isn't  
redefined"
     end
end

class FirstChild < Parent
      def redefinable_method
              "This is the custom string for the FirstChild class"
      end
end

class SecondChild < Parent; end

I don;t see what you  gain by meta-programming here