From: "Mauricio Fernández" <batsman.geo@...>
Date: 2004-04-29T16:07:11+09:00
Subject: Re: alias or alias_method problem

On Thu, Apr 29, 2004 at 01:18:38PM +0900, Jeff Mitchell wrote:
> 99% of the time alias_method is used in conjunction with
> redefining a method.  The above issues would have been
> avoided if ruby had something like,
> 
> redef foo(*args)
>    puts "new foo"
>    previous(*args)  # calls old foo
> end


batsman@tux-chan:/tmp$ cat redef.rb
class Module
    def redef(meth, &block)
        prev = self.instance_method(meth)
        define_method(meth) do |*a|
            block.call prev.bind(self), *a
        end
    end
end

class A
    def foo(*a)
        puts "A#foo #{a.inspect}"
    end
end

a = A.new
a.foo

class A
    redef :foo do |prior, *a|
        puts "new foo"
        prior[*a]
    end
end

a.foo
batsman@tux-chan:/tmp$ ruby redef.rb
A#foo []
new foo
A#foo []


More details in [ruby-talk:97440].

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