[Vm-dev] Compact class question

Yoshiki Ohshima yoshiki at vpri.org
Tue Dec 7 10:30:18 UTC 2010

At Tue, 7 Dec 2010 10:53:12 +0100,
Gabriel Hernán Barbuto wrote:
> Hi Yoshiki
> Maybe I have not made myself clear about which expression my comment
> referred to. Read my mail again, but I will copy it here again:
> headerWords :=
>        contentsWords > 63
>                ifTrue: [3]
>                ifFalse: [(cl indexIfCompact > 0) ifTrue: [1] ifFalse: [2]].
> Replacing the 63 for a 62 will make the trick and besides if
> contentsWords is greater than 62 it should be greater than or equal to
> 63. So what you propose is the same. But be careful that it's not in
> totalWords expression.
> I think this object should have a 3-word header. What do you think about this?

  Yes, I think so.

  I didn't quite understand the intent of original question ("Is it
fine to have an instance of compact class that doesn't have a one word
header?").  The answer, as Bert wrote, an object needs to have the
base header, if the "one word header" refers to the base header.

> With respect to what we are doing. We are porting MicroSqueak to
> Pharo. MicroSqueak could be useful for teaching. The next step(we are
> also working in parallel on this) is to build kernel images but
> different from MicroSqueak. In order to do that, we need to remove all
> the bad dependencies on the kernel classes and clean up the Pharo
> image.
> What are you doing with MicroSqueak?

  Cool, and thank you.  In some ways, what we are doing is similar; we
wrote an app in Squeak but trying to understand what other parts of
Squeak the app is using and going from bottom up sounds like an
intersting idea.

-- Yoshiki

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