Pd externals are currently written in C (possibly C++). There are python interfaces to Pd, and externals for the JVM, but what I'd really like is to write externals in Scheme.
Shriram said once that a PLT Scheme implementation of a particular GC algorithm could be used to general a “1st cut” C implementation. I need to find out if he meant that you could generate the C automatically from MzScheme, or if you need to grab a C translator (or roll yer own).
Why? Because this would give us a fast-path for conjuring Pd externals using my favorite language system. And of course it would be generally useful to the Pd community at large. Note that FFI might be required if any external C libs are necessary.
Note: it may then be required to come up with a PLaNeT library for doing signal processing.