From: George <george.marrows@...>
Date: 2005-04-08T17:39:44+09:00
Subject: Re: Seven new VMs, all in a row

> I'm not *building* a Ruby VM on top of a Smalltalk VM.  The Smalltalk

> VM will be allocating Objects and JIT-ing bytecodes natively.  There
is
> almost no Smalltalk in the Smalltalk VMs, and what semantics there
are
> are a very good fit for Ruby anyhow.  All I'm doing is providing
enough
> meta-Ruby to enable the Smalltalk VMs to run Ruby (including a Ruby
> compiler written in Ruby).

I'm curious - how good a fit are Ruby semantics for Smalltalk VMs? Do
Smalltalk VMs/bytecode provide the following Ruby facilities, and, if
not, how easily can they be emulated?

- blocks (with Ruby semantics in case they're different from
Smalltalk's)
- mixins
- instance variables that don't need to be predeclared with the class
- class variables & constants
- throw/catch
- exceptions
- continuations
- support for OS facilities like select, signals etc

Too great a mismatch between Ruby and Smalltalk semantics will mean
that an emulation layer will be needed, which will presumably reduce
the performance gains. Of course, I hope that's not true! Good luck
with the project.

-- George