June 15, 2009 — Thomas ten Cate

Work on this project has been slow until a few days ago, but now I’m back in business. I’m getting the hang of this Eclipse API thing, which makes everything go much smoother. Today I present to you: a more robust Scion client, a rudimentary “Open Definition” feature, and a configurable path to the Scion server program.

The improved client code for the Scion server works with a command queue. It spawns one thread that is tightly coupled to the server process. This thread waits for a command to arrive in the queue, then sends it off to the server and waits for the response. If the server crashes for some reason, it will be restarted and the command will be retried on the new incarnation. The original sender of the command (for example, a GUI element) specifies a timeout: if the command is not executed successfully within this time, the client gives up and the original sender is left to deal with the problem in whatever way it sees fit.

Then, for the mandatory screenshots, I built a feature similar to the “Open Declaration (F3)” feature that you might know from Java development in Eclipse. You can select an identifier and hit F3 (or go through the context menu or main menu), and you will jump to the place where the identifier is defined:

This feature is very rudimentary: it only works if the definition is in the current file; you have to select the identifier; and the Ctrl+click that Java users may know does not work yet.

I also added a Preferences page to configure the location of the Scion executable. Autodetection is in the works, but is not there yet. Automatically installing Scion via Cabal upon request would also be a very nice feature to have.



This preference page may be a trivial feature, but very important: now that the path to my home directory is no longer hard-coded, other people might actually be able to try my code too! Feeling adventurous? See the next post!