Writing an ACPI driver - an introduction

Thank you for a fantastic article. I realize it's a bit old, but I'm really interested in getting to know the inner workings of drivers in linux, and this is the most hands-on information I've found as of yet, so I have some questions:

The driver you wrote, I don't understand if this is c or asl, and how I would go about compiling and installing it to make the driver get loaded and actually do something. Could you give a brief explanation? Or do you have any suggestion of where I might find useful information regarding this?

I have a programming background with knowledge of c, c++, java etc. but I have not touched drivers once.