Saturday, January 17, 2009

Another Voyage Through Eclipse

I spend a significant fraction of my working time staring at Eclipse. I fear that I'm a lifer. Even though rumors reach my ears that Netbeans has become usable, I just can't motivate myself to consider an alternative.

Some years back, I did some development in Eclipse. I was able to convince a client of ours that the best way to set up a linguistic workbench was Eclipse. We built a set of plugins. We submitted a raft of bug reports. Even a few patches. It worked. Sadly, the client decided that they preferred .NET, so off they went. Given the problems we had getting Arabic and Hebrew text to work right in Eclipse, and my recent discoveries, I'm not entirely sure that they were crazy.

All that is background. In the last week, I set out to build a simple tool for linguistic annotation. That is, display some text, and give the user very convenient, keyboard-based, tools to mark words.

I found http://www.vogella.de/articles/RichClientPlatform/article.html, which looked to be a good solution to the fact that the books can never keep up with the ongoing redesign.

And then the fun began.

The fundamental thing I wanted in my program was an editor. Historically, Eclipse editors have tended to be more entangled with the full IDE than other kinds of components. This problem turned out not to be solved in 3.4.

The turorial explains how to use the most recent Eclipse mechanisms for setting up the File menu and all of that. Unfortunately, the tutorial does not mention that as soon as you add an editor, the simple prescription fails.

To add an editor to an RCP application, you add an extension under org.eclipse.ui.editor. And, the next thing you know, you have a file menu, whether you want one or not. Before you can add the File Open that you want, you have to get rid of the old one. All this is complicated by the transition from 'actions' to commands. Under the 'new administration', things are supposed to be organized around commands, but there remains, not surprisingly, a mountain of code, examples, and documentation from the old universe.

Thankfully, a bit-o-googling revealed a recipe for this.

Next? Make Arabic look right.

When I last worked in this environment, the top of my lap was a Windows box. (I've since spent some time chained to a copy of Ubuntu and moved on to a Macbook Pro.) There were some problems with Arabic; the SWT people hadn't thought all that much about an application running with an overall English locale that needed to do a clean job of displaying some RTL text. However, we got reasonable results on Windows.

Mac OS X? Uh, oh. SWT, it seems, has some fundamental assumptions about how systems will support RTL languages. Even though RTL languages (in general) work fine on Mac OS, there is an impedance mismatch with SWT. Net result: there is no simple way to set up a StyledText component to display Arabic or Hebrew correctly. Luckily for me, I don't absolutely need this tool to look beautiful on MacO OS.

1 comment:

Lars Vogel said...

I'm glad you like my RCP tutorial. Regarding other Eclipse topics you find lots of recent stuff here: http://www.vogella.de/eclipse.html

Especially the commands are (I hope) well described here: http://www.vogella.de/articles/EclipseCommands/article.html

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