From: Hal Fulton <hal9000@...>
Date: 2004-09-24T00:19:01+09:00
Subject: Re: Design Advice: Sub-Class 'Instances'

Gavin Kistner wrote:
> I'm starting to design/write an uber-ambitious home automation hub, in 
> Ruby. In addition to having convenient things like a web-based GUI 
> front-end, scheduler, and so on, the heart of this application is that 
> it will (eventually) work with any automation hardware whose 
> communication protocol is open (or reverse-engineered).

This pleases me more than I can say.

I have a similar project which I outlined and began to code, but I ran
out of steam when I had problems debugging my X10 code.

See http://rubyhacker.com/domo.html

Let's see if we can develop some synergy or just plain merge these
projects.

I'm not picky about all the design details of "my" project; if I don't
have help with it, it will never materialize at all; and if I do have
help, the other person(s) will contribute to the design.

> Questions
> 1) Is there a way to inspect the runtime state and figure out which 
> subclasses exist for a given class?

I think there's a hook by which you can have a callback keep a list. I
forget the name: inherited I think. ri seems incorrect on that one.

> 2) Is there a better way to force/detect if a subclass implements 
> certain methods?

Well... you might just use the callback technique again and maintain a
list of methods that are redefined.

> 3) Is there a better way overall to achieve my goal?

Dunno... for some thoughts on creating classes dynamically, you might
want to look at this snippet: http://rubyforge.org/snippet/detail.php?type=snippet&id=25

For a fancy plugin architecture (which you can even reuse), look at
FreeRIDE's thing called FreeBase.

Definitely let's talk further.

BTW: I like HomeSeer so much that if I could get Ruby scripting to work for
it, I would almost abandon the idea of a Linux solution. It is "supposed"
to work, but the last time I tried, I couldn't make it happen. If you're
interested in looking at that problem, let me know. I would *love* to get
that to work, because then I could start scripting my entire house in
Ruby *today*.


Thanks,
Hal