On Sat, 04 Jun 2011 14:27:32 -0400, TommyVee wrote:
> I'm using the SimPy package to run simulations. Anyone who's used this
> package knows that the way it simulates process concurrency is through
> the clever use of yield statements. Some of the code in my programs is
> very complex and contains several repeating sequences of yield
> statements. I want to combine these sequences into common functions.
> The problem of course, is that once a yield gets put into a function,
> the function is now a generator and its behavior changes. Is there any
> elegant way to do this?
I don't quite understand the nature of your problem, but it seems to me
that it is easily solved by simply not using yield in the common
functions. Instead of:
def main():
for x in sequence:
if a:
y = a+b+c+d+e
yield y
elif b:
y = a+b+c+d+f
yield y
else:
y = a+b+c+d
yield y+1
(where each of the lines y = ... is meant to be a big block of mostly
common code), factor out the similar parts into one or more external
functions:
def f(a, b, c, d):
return a+b+c+d # big block of common code
def main():
for x in sequence:
if a:
y = f(a, b, c, d) # call the common part
y += e
yield y
elif b:
y = f(a, b, c, d)
y += f
yield y
else:
y = f(a, b, c, d)
y += 1
yield y
If this is not what you're talking about, an example may help.
> I suppose I can do things like ping-pong yield statements,
I have no idea what you think that means, but another alternative is to
loop over the generator output and re-yield it:
for x in f():
yield x
A nice piece of syntax that has been proposed for Python is "yield from",
which will do the same thing, but you can't use that yet.
--
Steven
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