From: "NAKAMURA, Hiroshi" <nakahiro@...>
Date: 2000-06-20T21:17:28+09:00
Subject: [ruby-talk:03556] Re: Ruby classes and inheritance

Hi,

> From: dave@thomases.com [mailto:dave@thomases.com]
> Sent: Tuesday, June 20, 2000 10:30 AM

> However, it's fun to think about implementing abstract base classes,
> just to see how it could be handled.

It is very fun.  I used to consider how can I show the interface of
my library explicitly.

  % ruby -r myclass -e 'p MyClass.instance_methods.sort' | Mail -s \
  "This is it!" customer@somewhere.com

Now I can do;

  % cat myinterface.rb | Mail ...

:-)

>     class Module
>       def abstract(*names)
>         for name in names
>           class_eval %{def #{name}(*a)
>                          raise NotImplementError, "#{name} not implemented"
>                        end}
>         end
>       end
>     end

Some "name.id2name" required?

// NaHi


class Module
  def abstract(*ids)
    for id in ids
      name = id.id2name
      class_eval %{def #{name}(*a)
        raise NotImplementError, "#{name} not implemented"
      end}
    end
  end

  alias implements include
end
  
module Stack
  abstract :push, :pop
end

class ConcreteStack; implements Stack
end

ConcreteStack.new.push