precursion 1.0.0
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Description:
precursion 1.0.0
precursion
precursion – Python module to avoid RecursionError: maximum recursion depth exceeded easily
Usage
Ok, let's write recursive function:
def sumrange(x):
if x == 0:
return 0
r = sumrange(x - 1)
return x + r
print(sumrange(10) # 55
Pretty simple. But what if we call it with bigger argument
print(sumrange(1000))
# RecursionError: maximum recursion depth exceeded
Let's fix it with precursion module:
@precurse
def sumrange(x):
if x == 0:
# return was:
# return 0
# now we need to use StopIteration exception:
raise StopIteration(0)
# recursive call was:
# r = sumrange(x - 1)
# now we use yield:
r = yield sumrange.r(x - 1)
raise StopIteration(x + r)
print(sumrange(1000)) # 500500!!1
That's it!
What is .r in sumrange.r?
It's unwrapped function, so you yield unwrapped generator
Pros and cons:
Pros
The code looks cleaner. Yep.
Cons
Function calls have performance and memory overhead, so using
the decorator is slower than if you use Tail-call optimization via while
or implement a stack inside a function.
License:
For personal and professional use. You cannot resell or redistribute these repositories in their original state.
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