I've been doing version management of law for 10 years. As Gioele said, (Hi Gioele!) it is a very very hard task to tackle. The problem is the 200+ years of tradition that you must drag along. In a prior life I've done version management for CAD data and software data. Those are both much simpler problems, largely because changes in procedures are so much easier when you don't have such a large legacy. As someone said, legislation is all about patching the law - although the more polite term is "amending" the law. While I have built and deployed a system to automate the generation of amendments and the compilation of law, building such a system to the more general case is mind boggling. For this to be accomplished, there is going to have to be a lot of buy-in from the legislatures themselves for they are going to have to be willing to change. That is the challenge - change at that level is a bit glacial. In the meantime, I am writing an HTML5 based legislative editor to at least get some substance behind the idea - it's at
http://legalhacks.org. I'll post a video on how it works tomorrow. It's still a bit fragile too - this stuff is hard.