HyperStudio can be extended through the use of New Button Actions ("NBAs"), and Extras. These can be written in a variety of Macintosh programming languages, and information on how to do this is included in the standard HyperStudio package.
HyperStudio offers programmers over 100 "callbacks". These are routines within HyperStudio that tell you about the overall stack environment, manipulate objects and data, and perform other useful tasks to make the creation of your own NBAs as easy as possible.
The source code provided includes versions in Think C version 6, version 7, and Code Warrior (for the PowerMac).
