From: Sean O'Dell <sean@...>
Date: 2003-11-22T02:51:21+09:00
Subject: Re: New Type Checking System Idea

On Friday 21 November 2003 05:52 am, Greg McIntyre wrote:
> 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.

Not in my proposal.  An interface is completely immutable.  For that exact 
reason.  =)

	Sean O'Dell