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Re: Paul Graham's PyCon Keynote

On Saturday 12 April 2003 10:15, Sundar Narasimhan wrote:
> That is interesting -- not only because of Java's strengths wrt. network
> comms and threads (lots of ModSAF code could have benefited from those),
> but Java's weakness along the UI and numeric performance/correctness
> dimensions.

I could not possibly agree more.  Empirically, these programs seem to
spend a lot of execution time in the computational geometry associated
with both simulated perception and kinematics (collision detection,
etc.).  The fact that this computational load grows at least order(n),
and the fact that now we're talking about "terrain" that encompasses
the entire globe out to geosynchronous satellites, requiring lots of
64-bit FP horsepower, makes that decision, well, interesting.

(Toss in the trend towards emergent models of crowds, cities, etc.,
and the need for speed (or at least parallelism) increases.)

> I must admit I don't entirely get the point about sp. purpose
> hardware/languages. (While there is *a* trend to specialize "within
> the desktop computer", isn't it also true that today one can program
> one's set top box w/ gcc and your cellphone in Java -- i.e. general
> purpose language/device growth is *another* trend -- and arguably more
> powerful? In fact, I would have thought that one of the reasons for
> Oak/Java and LLs in general was that the latter trend necessitates

I took Paul's comment differently.  When we're trying to write code to
simulate some human behavior, it's much nicer to write in something
more like MIT's Behavior Language...

(defbehavior avoid-contact
   :inputs hear-spooky-noise, see-enemy
   :outputs legs-do-your-stuff
   (whenever ((received? hear-spooky-noise) (output legs-do-your-stuff...))
             ((received? see-enemy) (kiss-ass-goodbye ...))))

... than in some mishmash of inherited or composed C++/Java classes
using if/then/else...

The ability to do things like that is what I find so glorious about
Lisp. Without a malleable (extensible? programmable?) language, I have
no idea how you can build something like this in an affordable way.

(But then, of course, I don't have several hundreds of millions of
dollars to spend.)


==== John Morrison
==== MAK Technologies Inc.
==== 185 Alewife Brook Parkway, Cambridge, MA 02138
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==== jm@mak.com