[ruby-talk:4894] Re: Re-binding a block

From: Dave Thomas <[e-mail]>
Subject: [ruby-talk:4892] Re: Re-binding a block
Date: Tue, 12 Sep 2000 21:00:25 +0900

> [e-mail] (Yukihiro Matsumoto) writes:
> 
> > I don't think it's good idea to change instance_eval.  How about this
> > yet another trick (using yet undocumented unbound method).
> 
> Unfortunately, sing instance methods doesn't quite work for me.
> 
> What I'm truing to do is implement something similar to Lisp's advice
> system, where you can hook a function, wrapping it in some additional
> code that executes before and after the original function. What I'd
> like to do is something like
> 
> 
>    class String
> 
>      hook :upcase do |_upcase, str|
>        res = _upcase(str)
>        res.tr '_', '~'
>      end
> 
>    end

maybe i'm missing something but why not just use alias?

    class String

      alias _upcase upcase

      def upcase
	res = _upcase
	res.tr '_', '~'
      end

    end
--
       yashi