SPDLib offers a number of interfaces for developers. SPDLib is developed in C++ and therefore this API can be used for adding further functionality. Although, Boost Python has been used to provide an interface to the python scripting language which provides an easier to use and faster development environment suitable for most users. Additionally, if you prefer a separate IDL interface has been written by John Armston but currently only supports reading of SPD files but writing will be added into the future.
For more information on the available interfaces view the language specific pages: