[Pharo-project] [Vm-dev] Re: Enhancing SmalltalkImage>>recreateSpecialObjectsArray to lower coupling

David T. Lewis lewis at mail.msen.com
Wed Mar 28 20:39:02 EDT 2012


On Mon, Mar 19, 2012 at 10:01:23AM -0700, Eliot Miranda wrote:
>  
> Hi Guillermo,
> 
> On Sun, Mar 18, 2012 at 5:46 PM, Guillermo Polito <guillermopolito at gmail.com
> > wrote:
> 
> > What about changing #recreateSpecialObjectsArray so having in mind some
> > classes like Bitmap or Display may not be in the kernel?
> > This only changes some lines like:
> >
> > ...
> >     newArray at: 5 put: (self at: #Bitmap ifAbsent: [ nil ]).
> >
> > ...
> >
> >     newArray at: 13 put: (self at: #Point ifAbsent: [ nil ]).
> >
> > ...
> >
> >     newArray at: 15 put: (self at:  #Display ifAbsent: [ nil ]).
> >
> > ...
> >
> >     newArray at: 34 put: (self at: #Point ifPresent: [ :cls | 0 at 0]
> > ifAbsent: [ nil ]).
> >
> 
> The last one isn't used in Cog (in fact indices 32, 33 & 34 are unused) and
> probably unused in the Interpreter.  David?

Good question. I took a quick look at senders of #splObj: and I do
not see any usage of these entries in the special objects array. It
appears that the entries are (or were) intended to support fast object
initialization:

	"Prototype instances that can be copied for fast initialization"
	newArray at: 32 put: (Float new: 2).
	newArray at: 33 put: (LargePositiveInteger new: 4).
	newArray at: 34 put: Point new.

I cannot guarantee that these entries are unused, but it may well be
that they are obsolete.

I guess one way to confirm this is to nil them out in the array and see
what breaks.

Dave





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