VIEWFRAME 1.1
William L. Colsher
creamneggs@aol.com

****************************************************************************
This article is reprinted from issue 2.2 (March/April 1992) of PIE
Developers magazine. Copyright(C) 1996 by Creative Digital Publishing
Inc. All rights reserved.
****************************************************************************

ViewFrame by Jason Harper is the first major developer tool for the
MessagePad to be published by a third party (in this case, Creative
Digital Systems, the publisher of this magazine as well). ViewFrame
consists of three applications:

* ViewFrame - a utility for examining and editing NewtonScript objects
* ViewFrame Editor - a tool for writing simple programs on the
MessagePad
* Programmer's Keyboard - to ease on screen entry of NewtonScript

	The full ViewFrame package requires a bit over 100K. Given the recently
released 1.05 system, you need a storage card. You'll also want to be
sure you have good backups on either another storage card or your
desktop by using the Newton Connection Kit early and often. ViewFrame is
a powerful package.
	What can you do with ViewFrame? The answer to that depends on how brave
you are (or how recent your backups are). ViewFrame's basic operation is
object browsing. You can use it to examine any object in the Newton.
ViewFrame also allows you to modify writable objects by changing the
value of slots or array elements, and adding and deleting slots.
Of course you can also browse soups (even create sophisticated queries)
and edit their contents as well.
	In addition to the expected object browser and editors ViewFrame can
decompile any CodeBlock into NewtonScript. There are a few limitations
(this is version 1.0 after all). For example, conditional expressions
aren't fully rebuilt into valid NewtonScript but rather left in a form
that reflects the underlying bytecode language. Also nested function
definitions aren't fully listed. In general the limitations are not a
problem since the only legitimate purpose of decompiling a copyrighted
program (such as the Newton OS) is education. You should also note that
anything you learn (that's not officially documented) using ViewFrame on
a specific Newton platform is most likely only relevant to that specific
machine. It is also usually illegal to decompile a program for the
purpose of "reverse engineering".
	When you get tired of browsing through the MessagePad's ROM you can
write some NewtonScript programs using the ViewFrame Editor and
Programmer's Keyboard. While you can't write complete applications, you
can learn quite a bit about NewtonScript. (For the many individuals who
want a taste of NewtonScript before investing in the NTK, ViewFrame is
the only game in town.)
	But wait, there's more! You can use ViewFrame to display objects on the
MessagePad without recourse to the Inspector. You can even have
ViewFrame call your application when ViewFrame is being closed so your
debugging code can shut itself off. Yep, you can finally debug
communications programs!
	Finally, like good ol' ResEdit, ViewFrame is extensible. You can add
your own Programmer's Keyboard or ViewFrame Editor if those supplied are
not to your liking. You can also write new object viewing and editing
functions. This process is somewhat more complex, but if you are in a
position where you need this functionality you also know enough to
create it fairly easily.
	By now you should be getting the idea. ViewFrame is a nearly
indispensable development tool, tremendously educational, and a whole
lot of fun. The manual is well written and includes a lot of information
that is not presently available anywhere else. 
	The only thing that ViewFrame doesn't have is a NewtonScript tutorial,
(nor does it contain any of the basic Newton documentation delivered
with the Newton Tool Kit). Complete NewtonScript novices still need to
gain access to at least the NTK documentation. (One obvious add-on
product is a NewtonScript tutorial with exercises tailored to
ViewFrame.)
	I highly recommend ViewFrame to every Newton programmer. Get it, Use
it, Whoop!