Difference operation from root

Question

Is there a way to make difference directly from root? I want to do something like this:

difference(){
    root();
    cube();
}

instead of this:

difference(){
    union(){
        object1();
        object2();
        .
        .
        objectN();
    }
    cube();
}

Answer 1

difference() module subtracts all other children from the first one. In first snippet, first child is root(), in second first child is union(), and in both cube is subtracted.

Answer 2

You are already on the there. You just need to define root() and cube() as modules like so:

difference(){
  root();
  cube();
}

module root(){
  object1();
  object2();
  ...
}

module cube(){
  //some cube definition
}

In the background OpenSCAD will secretly create a union() around every module for you, just as if you wrote:

module xyz(){
  union(){
    //objects
  }
}

So in this example an object root() is created and cube() will be subtracted from this object. By using the module definition you keep your code just as modular as you ask for.

You may also want to have a look at the official docu and cheat sheet here.