I tried:

class foo_iter():
    def __init__(self, n):
        self.n = n
        self.i = -1

    def __iter__(self):
        return self

    def __next__(self):
        self.i += 1
        if self.i < n:
            return self.n
        raise StopIteration

It showed up in dir(), but foo_iter didn't appear to have __iter__ or __next__ methods.

I tried calling foo_iter(5) from shedskin-compiled code, and got:
*WARNING* rolling_checksum_ss_mod.py:26: '__iter__' is not supported
...so it's sounding like this isn't going to happen without changes to shedskin itself.

hi dan! yeah, these are currently not exported, so you'll have to find a work-around. I don't know if I will ever get around to implementing this..

older issue about this:

#133

btw we probably need at least a warning when generating the extension module..