From: Sean O'Dell <sean@...>
Date: 2003-11-21T13:46:25+09:00
Subject: Re: New Type Checking System Idea

On Thursday 20 November 2003 08:17 pm, Greg McIntyre wrote:
> "Sean O'Dell" <sean@celsoft.com> wrote:
> > Internally, though, Ruby would store the interface information in its
> > own way.  When a class declared that it implements it, as methods are
> > added to the class which fulfill the interface requirements, they
> > would be checked off until the last one, then a flag would be raised
> > for the class to indicate that it fully implements the interface.
>
> I don't think they need to be checked off. Couldn't the "end" which
> finishes the class definition (or part-thereof) signal a single check?
> It might be a more complex check and hence the same overall efficiency,
> or it might be better. *shrug*

Well, code can be called during class loading that might also inject new 
methods.  I guess it still could all be saved for one big check at end.  I 
think that is definitely a possibility!

> > > And just to clarify, what I meant by "too much work" was that when
> > > you define a class, you implicity define its interface (although
> > > this interface in Ruby 1 only has method names and arities), so I
> > > wouldn't want to have to define a class's interface separately in
> > > order to say"ensure this object implements this _class's_
> > > interface".
> >
> > No, the definition is written once and then methods refer to the
> > interface by its name only.
>
> Well, matz in another post says he's against implicit interface
> definition through class definitions.

I meant, the interface is written once separately from the class definition, 
sorry!

> I think I might have a go at implementing my proposal (or
> over-simplification as the case may be) in Ruby 1.8 because it's a
> hybrid between Ruby 1 and your proposal. Then I could observe how the
> interfaces get broken and fixed with the removal and addition of
> methods. :) I can also include an explicit method call to check a set of
> parameters implement a set of interfaces, so you'd have optional
> parameter type (or rather interface) checking too.

Oh definitely, you should!  At least give it a test run and see if wants to 
float.  The end solution will probably be some sort of conglomeration of 
ideas boiled down into one simple idea.

	Sean O'Dell