[squeak-dev] SmalltalkImage semi-self-references

Nicolas Cellier nicolas.cellier.aka.nice at gmail.com
Sun Jul 21 13:08:44 UTC 2013

Currently, SmalltalkImage current == Smalltalk.
SmalltalkImage current should not be used anymore, but should rather be
replaced with Smalltalk
(we did not change the too many senders, maybe this was not the best

As Tim said, since the SystemDictionary was bloated with many system
utilities, we turned it the other way around: let Smalltalk be a reflection
of the system, and separate the SystemDictionary to Smalltalk globals.
Note that Smalltalk globals printString used to answer 'Smalltalk globals',
but it was changed since Environment, it now incorrectly answers
'Smalltalk' which is not an environment...

Now whether Smalltalk should be self from within SmalltalkImage, I'd rather
say yes, but it makes sense if ever there is another SmalltalkImage.
Of course, all this was pre-Environment, so it might continue to evolve.

If we want to reify a VM object, then we would probably access the
currently used one through Smalltalk vm (and currently, it answers self,
because SmalltalkImage reflects the whole system).
Same for operating system, see Smalltalk os...

SystemNavigation provides low level system reflection capabilities (all
implementors of, etc...) + higher level UI requests.
It looks like we could give it more care, because it uses ToolSet for most
UI requests, and has 2 unused instance variables for determining browser
Whether it should be re-integrated to Smalltalk (TheSystem) or not, I don't
know, but what I wonder about is what should be the proper tools to handle
environments. Should we restrict the browsing to a specific Environment
(see SystemNavigation for: anEnvironment), or should we offer
cross-environments capabilities?
It all depends what we use environment for. Maybe we will need some kind of
sub system, a system in the system...

2013/7/20 David T. Lewis <lewis at mail.msen.com>

> On Sat, Jul 20, 2013 at 10:09:01AM -0700, tim Rowledge wrote:
> >
> > On 20-07-2013, at 9:36 AM, Bob Arning <arning315 at comcast.net> wrote:
> >
> > > When I see longer ways of saying something replacing shorter ways, I
> always wonder if the perceived benefit has been realized. Are there success
> stories out there for "SmalltalkImage current" enabling something cool that
> "Smalltalk" could not?
> >
> None that I am aware of.
> > IIRC the original idea was that SystemDictionary was overloaded with
> nothing-to-do-with-dictionary methods and needed to go on a diet. I don't
> recall it being suggested that the smarter thing would have been to remove
> the *dictionary* stuff and put that somewhere else to use as an environment
> for compiling, leaving the useful system management methods attached to
> something called 'Smalltalk'. I really don't like the current (sic) setup
> where there is SmalltalkImage SystemNavigation and Smalltalk and probably
> other split out stuff I haven't even found.
> >
> > Time for re-unification.
> >
> Yes. Some if this is half-finished work that probably falls under the
> category
> of what Andreas rather uncharitably (but accurately) referred to as "random
> refactorings" from the Squeak 3.9 era. From my point of view, it was stuff
> being shuffled about for the sake of moving it around, but without a
> coherent
> conceptual basis for the "improvements".
> Having said that, I do think that allowing "Smalltalk" to become a dumping
> ground for otherwise homeless methods is not a very good idea either, so
> some
> amount of refactoring is in order. And I think that it is a good thing to
> have
> some conceptual separation between things that are associated with the
> Smalltalk
> environment itself, versus things that are associated with the virtual
> machine
> (capabilities or lack thereof in the supporting VM), versus things that are
> associated with the underlying platform (operating system, file systems,
> and so forth).
> I have not really wrapped my head around Environments yet, but I'm pretty
> sure that this is a very good thing, and that it will help to clarify
> things
> conceptually. So this seems to be a good time to rethink some of the
> earlier
> mis-factorings and put them into a more clearly defined context. So, for
> example, the notion of a "current Smalltalk image" seems like complete
> nonsense to me, but the the notion of a current Environment might make a
> lot of sense. The notion of a current VM also makes sense (we restart our
> images on different VMs that have different capabilities). And it probably
> makes sense to have something that represents the current operating system
> platform (the "same" VM might be running on different operating systems
> and/or different file systems).
> Dave
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