[squeak-dev] Re: [Vm-dev] Bug in writing compressed stream when saving an mcz (was: New Cog VMs available...)

[David T. Lewis]

On Sat, Jul 19, 2014 at 09:50:42AM -0700, tim Rowledge wrote:
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> 
> > 
> > It is internal in the Cog VMs.  And before you condemn that choice it /is/ slightly more efficient as it doesn't have to indirect to access the interpreterProxy API.  But in any case new Cog VMs are already available.
> > 
> > 
> I know - your more direct macro access is a good idea. But that wasnt the point I intended; unless we've broken the plugin mechanism over the years a fixed-up zip plugin will over-ride the broken internal code, offering a very easy fix. It should even work in a running system where you don't want to quit and restart with a new vm for whatever reason. Something like 
> Smalltalk unloadModule: 'ziplthingy'
> Should disconnect from the old version and the next call to anything in the plugin ought to load the new external copy. Obviously this could be complicated by any stored state, so caveat emptor.
> 
> It's a really neat trick when developing a plugin.

Yes, this mechanism does work, and it is quite feasible to distribute an
external plugin to override an existing internal plugin. You are right
that is it not necessary to distribute a new VM. From the point of view of
a Squeak user who may not be familiar with how the VM is put together, it
may be something of an academic point since we have no extablished process
for distributing plugin updates independent of the full VM installations.

Dave