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Komodo is available under a complex licensing scheme. If you want to use the Windows release, you must become a member of ActiveState's developer network; the Linux version can still be downloaded without registration, but it's time-limited. Whichever version you select, be prepared for a shocking download. The installation file is more than 20 megabytes. A full installation is therefore even larger.

After installation, you can start to explore the interface (see Figure 1). Komodo looks pretty much like any other ISO-standard IDE: browser pane on the left, tabbed document pane on the right, message output and debugging pane at the bottom. On top are the standard toolbars and menus.

Figure 1 The Komodo IDE.

So far, so good. I like ISO-standard IDE's—it's a good, working design. As my constant practice is to try out everything I investigate for a review on a real project, I decided to try using Komodo for a week on the small scripts and projects for the fifth chapter of my work in progress—a book on GUI programming with Python and PyQt. I'm pretty much a Linux-only user, so that was the version of Komodo I have used most frequently.

This proved to be unexpectedly difficult. Komodo was slow. Not slow as in "a bit sluggish, but fairly usable," like Pythonworks, but slow as in typing a full line of code and still not seeing a character onscreen. However, after contacting David Ascher of ActiveState, it turned out that they were quite aware of the problem and working around the clock to solve it. It appears that the combination of GTK, Mozilla, Scintilla, and their custom plug-ins was a bit too esoteric. But shortly afterwards, a new version of Komodo for Linux was posted on their web site.

Their work was not in vain—this version was much, much smoother. Still no speed demon, everything moves rather leisurely around, but it is decidedly usable. If you open a file, a quite familiar sight awaits you. The folding, typeface spacing, whitespace marking firmly declares the editor component to be Neil Hodgson's Scintilla. Komodo makes full use of everything that Scintilla provides, and deserves full marks for that. Komodo offers background syntax checking, which is a lot like the background spell checking that the major word processors have offered for years. Auto-completion and calltips are available on Windows, but don't work yet on Linux.

What are the unique features of Komodo? The editor is decent, perhaps, but nothing outstanding. It still lacks auto-indent, but Komodo supports a vast array of languages, including fun ones like Lua.

The debugger is okay, and keeps the current line of source in view, but it doesn't really take things to new levels of power, like Wing IDE's debugger. Another annoyance is that it doesn't know where to stop. Pythonworks debugger can be told not to descend into the Python standard libraries such as string.py, but Komodo will happily lead you all the way down. But the fact that Komodo can also debug other languages, even XSLT, is very interesting. A feature I didn't test was the remote debugging; you can attach to a running script on another machine. It's a lot like Wing IDE's debugger in that respect.

There are also many hiccups. These small annoyances make working with Komodo rather unpleasant—like sitting down behind a badly configured Emacs. For example, the menu shortcuts work only when the editor window has focus—not when the debugger window has focus. I experienced a few crashes, too. No doubt these problems will be fixed: The Linux version I used was essentially a beta, and a lot better than the first version I tried.

One great feature, though, is the regular-expression testing environment (see Figure 2). This is a real boon for people who don't yet dream in regular expressions, and I confidentially expect this to become a much-copied feature in other IDEs. The idea is simple: Type a regular expression in the top pane, a test text in the bottom pane, and test the expression. If I'd had this a month or two ago, it would have saved me quite a few bug reports for Kura, my language-parsing application.

Figure 2 The Rx Toolkit.

The project-management facilities are still a bit immature. I'd like to be able to set a single file as startup file for the whole project, for instance. But if you work with both Perl and Python, and perhaps other languages such as XML, XSLT, or JavaScript, Komodo allows you to keep on using the same environment. There's no direct support for GUI programming in Komodo.

In sum, Komodo is the seed from which can grow a very powerful multi-language editor with integrated debugger and project management. The foundation is perhaps a bit too solid, since Mozilla weighs a ton, but the ActiveState team is moving forward very rapidly. I can't help but feel that if they had tried to code the same application using a dedicated cross-platform toolkit such as Qt, instead of a complex combination of C, Mozilla, XPCOM, GTK, Python, Perl, JavaScript, and some specific plug-ins, they might have had a working IDE quite a bit sooner, with fewer bugs.

The regular-expression toolkit is a great plus, and an environment that offers smooth, integrated editing and debugging of a multitude of scripting languages should come in very handy. In my daily work I use Python, XML, XSLT, Java, bash, C++, SQL, Make, and diff—and of these only bash isn't supported by Komodo. If you're in the same situation, it might be worth your time to evaluate Komodo yourself.

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