kunigami

def generator():
    yield from generator2()
    yield from generator3()

kunigami

def generator2():
    for i in range(10):
        yield i

def generator3():
    for j in range(10, 20):
        yield j

def generator():
    for i in generator2():

kunigami

def add(x, y):
    yield x + y

def main():
    result = yield add(2, 2)
    print(result)
    yield

main_cr = main()
# add() is not executed

kunigami

class Task(object):
    def run(self):
        while True:
            try:
                result = self.target.send(self.sendval)
                
                if isinstance(result, SystemCall): 
                    return result
                
                # sub-routine call

kunigami

def server(port):
    sock = socket(AF_INET,SOCK_STREAM)
    sock.setsockopt(SOL_SOCKET,SO_REUSEADDR,1)
    sock.bind(("",port))
    sock.listen(5)
    while True:
        yield ReadWait(sock)
        client, addr = sock.accept()
        yield NewTask(handle_client(client, addr)) 

kunigami

class ReadWait(SystemCall):
    def __init__(self, file):
        self.file = file
        
    def handle(self):
        fd = self.file.fileno()
        self.sched.waitforread(self.task, fd)

class Scheduler(object):        

kunigami

# Excerpt from http://www.dabeaz.com/coroutines/pyos4.py
    
# coroutine that will be wrapped in a task
def foo():
    mytid = yield GetTid()
    ...

# A system call
class GetTid(SystemCall):
    def handle(self):

kunigami

def get_words(step):
    f = open('/usr/share/dict/words', 'r')
    for line in f:
        step.send(line.strip())

@coroutine
def filter_step(step):
    while True:
        line = (yield)
        if (line[-3:] == 'ion'):

kunigami

@coroutine
def echo():
    print("initialized")
    while True:
        line = (yield)
        print(line)

kunigami

def coroutine(fn):
    def start(*args, **kwargs):
        gen = fn(*args, **kwargs)
        next(gen) 
        return gen
    return start