.. Copyright SAS Institute .. _sastk: ****** SAS TK ****** The SAS TK subsystem is a set of components used for various operations in SAS products. It can be thought of as SAS' standard library. The binary communication used by CAS is included in the functionality of these components. In order to support binary communications with CAS in SWAT, a subset of the shared objects (or DLLs) is included in the SWAT install file for supported platforms along with a Python extension module that interfaces with them. In addition to communication with the CAS server, the TK components also contain functionality for applying SAS data formats to Python values for rendering purposes. This includes only the standard SAS data formats, not user-defined formats. If you plan to use the binary protocol of CAS, the SAS TK components are required. The REST interface can be accessed using SWAT's Python code. For more information on protocol comparisons, see the :ref:`Binary vs. REST ` section. The SAS TK components are also released under a separate license from the Python source. See :ref:`Licenses ` for more information.