Tom --

I think this is a good approach. I've always thought of the "levels" as
more on the same level, but with different kinds of fences around them ...

Cheers,

Alan

At 11:05 PM -0000 12/28/98, Tom Morgan wrote:
>SystemDictionary become: nil.
>
>I got curious when the fragment was posted, to think about
>what exactly this means and what it does (in addition to
>crashing the VM).
>
>In the responses to this post and in the discussion of
>other impressively disruptive expressions, the idea of
>'levels' kept coming up.   Plainly,
>
>  SystemDictionary become: nil.
>
>*means* more than a 'simple' assignment does.
>
>One of the points that has been made on the list is that even
>'simple' assignment is/can be thought of as a meta operation --
>it is, in effect, the recompilation of the accessor for the
>variable assigned to.
>
>Worthy of Lord Shiva, the operation:
>
>  SystemDictionary become: nil.
>
>is spectacularly a meta-operation, since it destroys every
>name in the image, and the possibility of ever naming
>anything, at *any* meta level, ever again.
>
>One way of thinking about this could be to regard the assignment
>as properly happening all the way up the reflective tower, at the
>'top' of an infinite number of meta levels.
>
>This might be a clue about how to arrange an environment,
>where these kinds of spectacular operations are possible, yet the
>environment is safe for mere mortals.
>
>-As a mere mortal, I may make and revise the values in my image.
>-As a demigod, I may make and destroy the names of mere objects.
>-...
>-...
>-...
>-As Shiva, destroyer of worlds, I may destroy the very ability
>to name.
>(It would be also nice to imagine the ability to
>re-create the ability to name, within the confines of the
>self same meta structure)
>--
>I think that an important element of a re-do of the Smalltalk
>meta structure should be an incorporation of the 'levels' of
>meta operation in an explicit way.
>
>People seem to do live life with blurry use/mention distinctions
>*most of the time*, so there should a light touch to the
>explicitness of the meta levels -- there if you needed them,
>in the background if not.
>
>   ...Tom M
>
>
>
>
>--
>+---Tom Morgan ------------------------------ (tmorgan at acm.org) -----+
>I   Brooklyn Union                          Phone: 1 718 403 2427    I
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