Hi, Crispin! I just wrote a PostScript interpreter for NeWS in PostScript, 
and I thought you might be interested in looking at it. It was based on 
some of the ideas you wrote about in the paper about your PS interpreter, 
in the Springer Verlag book on workstations and publication systems. 

It has its own execution stack, a PostScript array, onto which it 
pushes continuations for looping constructs such loop, forall, etc. 
The continuations are represented by dictionaries in which are stored the 
state needed by the control structure (plus some other info to help with 
debugging), as well as a function /continue, and a /continuation type. 

The interpreter's execution stack is stored in a dictionary that the 
interpreter stashes away on the NeWS execution stack during the execution
of primative operators. (By calling the function MumbleFrotz. Note the 
circularity.) 

There is some hair in there to handle the NeWS /send operator correctly,
in iexec-reenter. There are still a few things unimplemented, but on the 
whole, it seems to work! 

I expect that it will be useful for debugging PostScript code in NeWS. I 
did it because there was no other way to single step through execution in
NeWS. The NeWS execution stack is actually a C structure that is not 
mallable from PostScript, and doesn't even give all the necessary information
(like the "for" step and limit). 

Any suggestions for making it faster or more flexable?
Do you think it would be useful with your PostScript interpreter? 

	-Don