AppleScript is simultaneously one of the most-powerful and one of the least-used Macintosh utilities, the latter partially due to serious deficiencies in Apple's own Script Editor. Late Night Software's Script Debugger 2.0.3 makes AppleScript more usable by providing a powerful yet accessible development environment, though compatibility issues and high cost limit its usefulness.

Code Tracing and Bug Tracking

The latest version of Script Debugger adds a troop of features. For example, while the previous version could debug only global variables, Script Debugger 2.0 can also track local variables. You can set break points and watch points, and the program supports the ability to step into, over, and out of handlers. The included AppleScript debugger dialect lets you follow scripts outside Script Debugger itself -- a requirement for testing CGIs, droplets, and folder actions.

The attractive tabbed-palette interface allows easy access to clippings, application dictionaries, open windows, and scripts, and you can rearrange or hide the tabs. The main editing window supports split-pane editing and optional soft wrapping.

Script Debugger's primary competitor is the recently released Scripter 2.5 from Main Event Software ( www.mainevent.com ). The two programs are identically priced and fairly comparable, although each has its vocal proponents. However, when Main Event released its latest upgrade, it also released a light version of Scripter -- the $89 Scripter Personal Edition. If you haven't yet ventured into AppleScript's depths, you can dangle your feet in the water with Scripter Personal Edition -- and save $100, to boot.

Verbose Scripts No Problem

If you're a hard-core scripter, you'll find a lot to like in Script Debugger 2.0. Unlike the competition, it can handle scripts larger than 32K. Also unlike the competition, Script Debugger is itself scriptable, which enables it to interact with utilities and allows its scripts to change themselves.

But these new features are not without flaws. You can't use Script Debugger to script Microsoft Word 98 or Excel 98, nor can you use the program to debug AppleScript inside Digital Technology's FaceSpan, a scripting and user-interface-creation utility.