Given that work has gone into plugins for VST and Faust, I figured there might be some interest in this. There’s an opensource JSFX implementation that works in PureData, Max and probably others.
JSFX is a JIT language, that’s reasonably high level, that compiles down to reasonably fast plugins (it was developed for Reaper). There are also a bunch of pretty good plugins developed in it.
Below is a picture of me using VSTPlugin to host the fabulous ReEQ. You can set all the parameters of the plugin via standard VSTPlugin set commands, edit the JSFX code directly in the VST host, and the CPU running this plugin is about 1.5%. Overall, this is excellent and just works.