From: Greg McIntyre <greg@...>
Date: 2003-11-21T22:52:19+09:00
Subject: Re: New Type Checking System Idea

It occured to me on the bus today...

Can interfaces be changed at run-time? I think they shouldn't because
allowing interfaces to be updated any time after they've been created
would mean that every object implementing the interface would have to be
re-checked. Maybe one could iterate (or some faster search) through the
object space (ObjectSpace), but it seems better avoided.

So this should be an error:

  interface IFoo
    # some stuff
  end

  # ...

  interface IFoo
    # add more stuff to IFoo
  end # => Error, redefinition of interface IFoo

The reason I say this is because it works differently to the way Ruby
classes work in a similar situation. It therefore has baring on deriving
interfaces from classes implicitly (which I'm still thinking about, a
little bit). However if you do it explicitly and optionally, on a
particular line of code, I think you're fine because you choose at which
point to grab the class's interface.

-- 
Greg McIntyre ======[ greg@puyo.cjb.net ]===[ http://puyo.cjb.net ]===