Even the US Constitution is pretty limited. The main body of the law is pretty much the Common Law, although of course each decision becomes part of that law, so it's not a static thing.
An example of how it all works is that the Constitution says one is entitled to "due process," but that's pretty vague. It's largely in the common law that the right of habeus corpus, the right to counsel, and the implementations of the bars against self-incrimination are made functional parts of the "due process."
China has a very nice constitution too.(?) The Weimar Constitution was a classic one.(?) I've even heard the French have one, but they can't agree on what it says.(?)