Use Case
I have a variable list of ordered generators that I am trying to chain together. By chain together I mean that I am taking some input and creating generator_1 from that input. Then I get the item_1 from generator_1 and use that to create generator_2.
This continues until I reach the last generator in the list; at which point I exhaust that generator.
Example
I have written this code, which reading it seems to do what I want but it is not functioning correctly:
def run(x):
functions = [one_produces_three, one_produces_one]
def recurse(idx, message):
if idx == len(functions) - 1:
yield message
else:
next_gen = functions[idx + 1](message)
for next_message in next_gen:
recurse(idx + 1, next_message)
return recurse(-1, x)
def one_produces_three(one_input):
for x in xrange(0, 3):
print "one produces three %s %s" % (one_input, x)
yield one_input + x
def one_produces_one(one_input):
print "one produces one %s" % one_input
yield one_input
if __name__ == "__main__":
for r in run(1):
print r
When I step through this with a debugger, the problem appears to be on line 10: recurse(idx + 1, next_message). For some reason this is a no-op, the recursive call never happens and the one_produces_one method is never called.
This is obvious when I run the code because I only get the output:
one produces three 1 0
one produces three 1 1
one produces three 1 2
The output I would expect would be:
one produces three 1 0
one produces one 1
1
one produces three 1 1
one produces one 2
2
one produces three 1 2
one produces one 3
3
Why is my recursive method call not being invoked?
