## 13.1 General Changes

### 13.1.1 Functors and Modules

Mozart now comes with a powerful internet-based module system that supports lazy loading, native modules and more. For an introduction see ``Application Programming''.

To make best use of the new module system, the previous Oz Standard Modules have been split into the base environment and the system modules. The compiler always provides the base environment, it contains all operations working on data structures like records, lists, and so on. For more information see ``The Oz Base Environment''.

All remaining modules (including the constraint programming support) are now provided as system modules that are subject to import in functor definitions. The system modules are described in ``System Modules''.

The Oz Programming Environment however still follows the design to ease explorative development. For that reason all system modules are still available in the Oz Programming Environment. The Environment nicely exemplifies the merits of the new module system: while providing all system modules the Environment starts in a fraction of a second by taking advantage of dynamic linking.

### 13.1.2 Applications

The rudimentary standalone application support available in DFKI Oz has been replaced by powerful abstractions and command line tools (see ``Oz Shell Utilities'') to support different aspects of application programming. In fact, a new tutorial (see ``Application Programming'') is entirely devoted to application programming with Oz and Mozart.