[cells-devel] Re: [PyCells] Thoughts after porting the first 6 tutorial sections

[Ken Tilton]

On 6/17/06, Ken Tilton <kentilton at gmail.com> wrote:
>
>
>
> On 6/16/06, Ryan Forsythe <ryanf at cs.uoregon.edu> wrote:
>
> >
> > On Jun 16, 2006, at 2:43 PM, Ken Tilton wrote:
> > > I downloaded it and it has the right size, but PicoZip (which
> > > normally does fine with tars and tgzs (but not always)) finds
> > > nothing to extract.
> >
> > Weird. I've uploaded a zip of the export, maybe that'll work for
> > picozip: http://pycells.pyworks.org/pycells-r12.zip
>
>
> Thanks, that worked.
>
> One quick reaction: in Cells, observers are more clasically OO, they are
> defined as a class attribute. I am not sure if PyCells is doing the same
> after a quick glance, but I do see that the Cell data structure has a slot
> for observers, which sounds as if in PyCells they might be Cell-specific.
> Correct me if I am wrong.
>

 I forgot to mention something (and I am CCing cells-devel to see what
others think): the idea of instance/slot-specific observers does not seem
like a bad idea. It certainly is consistent with Cells allowing different
rules for the same slot of different instances. Normal observers really do
have to be class-oriented (it does not how a color of a widget gets decided,
a change still has to trigger an OS update) but if PyCells happens to
support instance/slot-specific observers that would be OK.

The only problem I see is that you need a little new syntax. I suppose in
Cells it would be:

     (c-formua (:observer (observer-lambda () ......)...)


Does anyone recall ever needing an instance-specific observer?

kt
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