====

From: Hopkins, Don [mailto:Hopkins, Don] 
Sent: Sunday, November 08, 1998 3:06 AM
To: paul@isdn-balla.corp.sgi.com
Cc: dhopkins@maxis.com
Subject: RE: http://reality.sgi.com/grafica/motion/

I think something cool to do, would be to apply XML to describing user
interface layouts and behavior and constraints.

It would have to describe the interfaces and connections between the
components, as well as the graphical layout and properties.

It should have a general purpose message passing model that is
independant of any scripting language, and you could also embed
scripts in the xml in different language like is currently done with
html.

But you should be able to do a lot without even resorting to scripts,
just hooking components together.

And then if course I want to design a visual programming language in
XML.

XML is certainly expressive enough to describe the syntax of a
complete programming language.

So we could define a language for describing and invoking interfaces
in XML, with some control flow expressions, primitive data types, and
basic math and string processing functions.

Something really simple and essential like Lisp, but with XML as the
basic code and data type.

I imagine a free form visual graph-like data flow language, less tree
structured than Lisp, and manipulating (and representing programs as)
xml trees and properties instead of s-expressions.

The signatures of functions and interfaces would all be described by
metadata in xml.

So it would be possible to write a good visual editor and browser for
the language, and use it to construct and program all kinds of user
interfaces.

The user interfaces could be mapped from xml to dynamic html, and
there could be other mappings to different user interface platforms.

How would you visually represent lisp's "apply" function, in a visual
programming language using icons connected by wires?

You would be able to pass a reference to an icon with disconnected
inputs (to be satisfied by apply), along a wire.

Apply would take an input that was a function to be applied, and some
more inputs that were the arguments to pass to the function.

Inside the apply icon you might see an image of another icon
representing the function passed to apply, and wires going from the
inside inputs of apply to the outside inputs of the passed in
function. The function passed into apply could change over time, but
the signature would have to stay the same, unless the visual language
had a way to deal with dynamically reconfiguring the wires between
icons! (Or you could simply bundle a variably sized array of arguments
in a "cable").

	-Don

====

From:	      Mackraz, Jim 
Sent:	      Monday, November 23, 1998 1:48 PM
To:	      MAXIS CTGPROG @ Maxis
Cc:	      Trottier, Chris
Subject:      Ideas for next milestone...

I'm working top-down on the ideas for the next milestone (and I'll
share that, of course, once I discuss it w/ Kana, Luc, etc.)

Any good "bottom up" (or, hell, top down) ideas from y'all for things
we should be working on?

Try to find some time today to check your lists and stretch your
brains.

Thanks,
 Jim

====