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Volume Number: 15
Issue Number: 1
Column Tag: Viewpoint

Jan 99 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.