Handle an exception thrown in a generator

Question

I\'ve got a generator and a function that consumes it:

def read():
    while something():
        yield something_else()

def process():
    for item in read         


        

Answer 1

This is also something that I am not sure if I handle correctly/elegantly.

What I do is to yield an Exception from the generator, and then raise it somewhere else. Like:

class myException(Exception):
    def __init__(self, ...)
    ...

def g():
    ...
    if everything_is_ok:
        yield result
    else:
        yield myException(...)

my_gen = g()
while True:
    try:
        n = next(my_gen)
        if isinstance(n, myException):
            raise n
    except StopIteration:
        break
    except myException as e:
        # Deal with exception, log, print, continue, break etc
    else:
        # Consume n

This way I still carry over the Exception without raising it, which would have caused the generator function to stop. The major drawback is that I need to check the yielded result with isinstance at each iteration. I don't like a generator which can yield results of different types, but use it as a last resort.