PsyScope has facilties to support user-developed drop-in extensions which can implement new stimulus types, input types, actions, data filters, interface dialogs, and scripting functions. Early versions of a Programmers Manual and Developers Kit for PsyExtensions are currently available.
The PSYX Programmer's Manual describes the various kinds of PSYXs and how to create them in C on the Macintosh.
The PSYX Developer's Kit contains header files, and glue code necessary for compiling PsyExtensions, plus a testing/debugging environment for Metrowerks CW7 and example files and template code for various PSYX classes.