From: "Florian Groß" <florgro@...>
Date: 2005-04-04T23:31:50+09:00
Subject: Re: Ruby rite (Ruby 2.0) vaporware or real?

Richard Cole wrote:

> My major gripe with Ruby is that there's no static typing. I'd really 
> like to be able to do something like:
> 
> interface ISubject
>  def notifyAll -- unit
>  def addObserver(a -- IObserver) -- unit
> end
> 
> interface IObserver
>  def subjectUpdate(subject -- ISubject)
>  end
> end
> 
> class Subject
>  def initialize
>    @observerList -- ISubject IEnum = Array.new()
>  end
>  ...
> end
> 
> Why? because interfaces gives you a place define and explain protocols 
> of interaction. It also helps out the IDE, when you type @observerList 
> the IDE knows the type and can do name completion on it, hyperlink your 
> code etc.
> 
> Also interfaces inheritance is very different to reuse inheritance. It 
> is so much clearer intentwise for a framework if the interfaces are 
> explicit, rather than being implicit.
> 
> The major problem with interfaces is that you can't say later, oh, this 
> class implements that interface, but in Ruby, if there were interfaces, 
> the you could.

Please have a look at my ruby-contract library which offers this and 
more: http://ruby-contract.rubyforge.org/