From: David Flanagan <david@...>
Date: 2007-06-17T15:45:04+09:00
Subject: Re: new method dispatch rule (matz' proposal)

Steven Lumos wrote:
> Maybe I'm confused, which of these are you talking about?
> 
> class A
>   def m; @f(); end
>   def @f; true; end
> end
> 
> class B < A
> end
> 
> B.new.m  #=> Error: The mighty class author requires that you
>              reimplement @f.
> 
> or
> 
> class B < A
>   def @f; false; end
>   #=> Error: The mighty class author forbids you to reimplement @f
> end
> 
> Steve
> 
> 

Steve,

I don't intend either of those, really.  My proposal is that the method 
@f would be completely local to the defining class.  There is no 
inheritance of these hypothetical methods, and so the class hierarchy is 
irrelevant.  If you try to invoke @f in a class B that does not define 
@f you get a NoMethodError or whatever. And you can define @f in a class 
B regardless of what is defined in the superclass, so you'd never get an 
error message like your second one.

I think that the intent of the Matz's proposal from 6 months ago was to 
acheive something like this, and there seemed to be some consensus that 
that would be a good thing.  What I'm adding with my proposal here is an 
explicit punctuation prefix that would, I think, make it possible to 
implement this kind of local method without altering the method name 
resolution algorithm that is currently used for private methods.

	David