Jan 99 Viewpoint
Volume Number: 15
Issue Number: 1
Column Tag: Viewpoint
by Richard Gaskin
As Mac OS development tools continue to evolve, there is one important category which
is often overlooked in the Mac community: rapid application development (RAD).
The availability of robust RAD tools for Windows, most notably Visual Basic, is
arguably one of the primary contributors to the plethora of new applications written
for the Wintel platform, and absolutely critical to the entrenchment of Wintel in
corporate and academic environments where custom applications need to be cranked
out regularly.
RAD tools represent a critical component of Mac evangelism as well, allowing
opportunities for organizations to create custom solutions which fill market niches
and keep folks using Macs. Apple has been proudly citing the number of new
applications for Mac OS since the announcement of the iMac, but it seems a fair bet
that this number would at least double if the company took a more active role in
popularizing RAD tools for Mac OS.
In recent years, developers on other platforms have seen an increased awareness of the
value of scripting. As John Ousterhout of Scriptics Corporation put it in his seminal
white paper "Scripting: Higher Level Programming for the 21st Century
<http://www.scriptics.com/people/john.ousterhout/scripting.html>:
"Scripting languages and system programming languages are complementary, and most
major computing platforms since the 1960's have provided both kinds of languages.
The languages are typically used together in component frameworks, where
components are created with system programming languages and glued together with
scripting languages. However, several recent trends, such as faster machines, better
scripting languages, the increasing importance of graphical user interfaces and
component architectures, and the growth of the Internet, have greatly increased the
applicability of scripting languages. These trends will continue over the next decade,
with more and more new applications written entirely in scripting languages and
system programming languages used primarily for creating components.
Many of the most popular scripting tools on other platforms were inspired by Apple's
own HyperCard, including Asymetrix ToolBook and Visual Basic. The attraction is easy
to appreciate: by marrying a hierarchical GUI environment to an interpreted language
which automates most memory management, development cycles can be slashed by
orders of magnitude. Offering the same friendliness that is the essence of Macintosh,
HyperCard introduced programming for the rest of us.
Ironically, while Apple has spent millions on since-abandoned efforts like Dylan and
ScriptX, their most successful development tool, HyperCard, has never been enhanced
beyond its monochrome architecture and may soon be axed
<http://www.hyperactivesw.com/SaveHC.html>.
But in spite of Apple's lack of serious commitment to HyperCard in recent years, other
vendors have successfully expanded on the easy-to-learn language and are allowing
people to develop solid Mac applications in record time for their organizations, and
often for commercial distribution as well.
Many folks have the impression that any xTalk language (the collective term for
HyperTalk and related dialects) is unsuitable for serious development, but these
perceptions have more to do with HyperCard's implementation than any inherent
problem with the language or object model. At least two other vendors have
successfully enhanced xTalk in ways that are extremely potent for RAD work.
For cross-platform deployment, MetaCard <http://www.metacard.com> offers a very
similar object model as HyperCard, but also offers multiple windows in different
styles, integrated color, rich media support, and has one of the fastest interpreters in
the business. Being the only xTalk which allows authoring and deployment on all
major platforms (Mac OS, Windows, and UNIX), I have found it to be an excellent
substitute for Java for many projects, allowing me to enjoy universal deployment at a
fraction of the development time. And because scripting is essentially a shorthand glue
between compiled routines in an interpreter, many operations run noticeably faster in
MetaCard than equivalent Java implementations. For GUI apps, MetaCard makes Java
look like "write once, crawl anywhere".
To make truly Mac-like software quickly, there is no better product than SuperCard
<http://www.incwell.com>. While SuperCard is currently only available for Mac OS,
it offers many of the advantages of MetaCard but is unencumbered by cross-platform
considerations. Like a software glove wrapped around the Mac OS, SuperCard allows
developers to take advantage of extremely modern Mac OS features such as the
Appearance Manager, speech recognition, QTVR, and what is probably the world's first
scriptable control over OS-level drag-and-drop. Try implementing all of these in
C++ in an afternoon. :) The rumor mill has it that the SuperCard team is working on
a suite of tools aimed at professional developers which will include an API for
accessing many of the program's internal data structures and routines. This would
allow developers to use SuperCard as a form of precompiled application framework, in
which the standard GUI stuff is handled in scripting while computationally-intensive
routines can be easily integrated from custom C code.
While there are limitations to developing with any 4GL, the advantages are compelling
for many applications, especially those designed for vertical markets, schools, and
smaller organizations where the greater costs of developing purely in C++ or Java
would be prohibitive. In those formal languages, development time in measured in
weeks and months, but in xTalk products these are often measured in days, or even
hours.
And even for projects based in C++, xTalk products provide all the necessary
ingredients for rapid prototyping, which can make a critical difference in early design
and usability discussions. Apparently Microsoft agrees: If my sources are correct,
even Visual Basic was first prototyped in SuperCard, on a Mac of course. :)
______________________________
Richard Gaskin is the ambassador of Fourth World <http://www.fourthworld.com>,
a Los Angeles-based consultancy specializing in scripting languages for Mac, Windows,
and UNIX. You can reach him at ambassador@fourthworld.com.