I just released python-fibers 0.2.0, which includes PyPy support! For those of you who may not know, here it what fibers are all about:
Fibers are lightweight primitives for cooperative multitasking in Python. They provide means for running pieces of code that can be paused and resumed. Unlike threads, which are preemptively scheduled, fibers are scheduled cooperatively, that is, only one fiber will be running at a given point in time, and no other fiber will run until the user explicitly decides so.
The funny thing here is that the implementation of fibers uses code (stacklet, more precisely) borrowed from PyPy, but the first version of fibers only supported CPython. On this version, a PyPy compatible version is provided, using the _continuation module. For reference, the greenlet and stackless implementations in PyPy are done using this module. It has been tested with PyPy 2.1, but let me know if you run into any issues!
You can grab it at your nearest cheese shop, get it while it’s hot!