Miki Tebeka wrote:
> Hello All,
>
> I'm looking for a way to "yield" an exception.
>
> Background: I'm writing a hardware simulator. I have an output buffer
> and need to freeze when it's full and then when called again to resume
> execution from the point where it stopped.
>
> Currently all I can think of is to use a class and save the state when
> throwing an exception. However this required manual book keeping of the
> current state (and it is complicated).
>
> I'd like to use generators but can't see any "nice" way of doing it.
> What I'd like it to throw an exception when the buffer is full and then
> next time the generator is called to continue execution as after a
> "yield".
I'm not sure if this helps or not, but as Peter was saying, throwing an
exception is counter to resuming a state machine as raising an exception
will halt execution.
You can however, yield exceptions through a generator, not raise them.
I do this occasionally in threaded GUI work. Here is a simple
micro-thread inspired interrupt. Note however, that the exception is
syntactic sugar, you can (and maybe should) use your own class for
managing your simulated hardware interrupts.
def work(res, length=10):
while 1:
if len(res) > length:
# oops, need an interrupt to handle the
# global state, the buffer is full
yield ValueError("length > %s"%length)
else:
res.append(1)
l = []
g = iter(work(l, 10))
while 1:
# work until an interrupt
err = g.next()
try:
raise err
except ValueError:
print "clearing the list"
del l[0:10]
>
> Is this possible?
> Can you recommend a good way of doing this? Any state machine?
>
> Thanks.
> Bye.
> --
> -------------------------------------------------------------------------
> Miki Tebeka <miki.tebeka at zoran.com>
> http://www.cs.bgu.ac.il/~tebeka
> The only difference between children and adults is the price of the toys.
>
>