Developping a Pebble.js app turned out to be quite easy : the most difficult part was understanding JSON (never used it before) and wrapping my head around the iRail API. After a few hours, I got a first prototype running, which showed me the next 5 trains leaving Brussels-South, together with the departure time, platform and duration of the trip. Today, I've added an option to choose your starting point, reaching a point at which this could be called a first alfa release.
There's still more work to do : not everyone uses the same commute stations as I do (they are currently hardcoded into the app), so those need to be configuration items in the app. So this needs to be addressed first before I can release it into the wild.
Also, the app currently only supports direct connections. There's some administrative work to do for releasing it on the Pebble appstore. The code currently lives in CloudPebble, I need it to import it into my local git repo as the code changes dramatically from day to day (really need to install GitLab onto my machine too). And finally, converting it to SDK3 for the new Pebble Time, so the departure times could appear into your timeline.