CODEWITHSUNDEEP
python
ImInfinite313
ImInfinite313

Reputation: 125

What are my options for navigating through subroutines?

Suppose I want a program Foo.py which has some arbitrary routines Bar(), Quux(), and Fizz(). Let's say that the usual order of execution from a procedural perspective should be Bar() -> Quux() -> Fizz(). However, Fizz() should conditionally call a function Buzz() depending on some runtime action, and calling Buzz() at any time during Fizz() should return the process back to Quux().

I have a fair understanding of how concurrent processes can be implemented in assembly using system calls depending on the architecture, but what options are available to me in Python, where I can't – and frankly would prefer not to – use lots of jumps and directly move an instruction pointer around? When searching for an answer, I found loops and recursion as a suggestion for going back in a program. I don't think a loop would work without stopping the Fizz() process to wait for the condition check for Buzz(), and I'm not sure how recursion could be implemented in this scenario either. (My Buzz() would be like a "Back" button on a GUI).

Upvotes: 0

Views: 59

Answers (3)

ImInfinite313
ImInfinite313

Reputation: 125

Using coroutines (multithreading) will provide the desired concurrent functionality. Source in the comments of the question and of user2357112's answer.

Upvotes: 0

Prune
Prune

Reputation: 77850

Perhaps flow like the below. Fizz loops until some condition evokes a call to Buzz. The same check that triggers the call breaks the loop.

import random

def Buzz():
    print ("Buzz")

def Fizz():
    print ("Fizz")
    while True:
        flip = random.random()
        print ("  ", flip)
        if flip <= 0.5:
            Buzz()
            break

def Quux():
    print ("Quux")
    Fizz()
    print ("Back in Quux")

def Bar():
    print ("Bar")
    Quux()

Bar()

Output:

Bar
Quux
Fizz
   0.88313135192614
   0.9782005471906149
   0.6899740417799126
   0.724911154764598
   0.6193573809551899
   0.3713918176393549
Buzz
Back in Quux

Upvotes: 0

user2357112
user2357112

Reputation: 281519

You don't need anything fancy here. The usual structured programming tools will work fine. Have Fizz return after calling Buzz, and have it return an indicator saying whether to go back to Quux:

Bar()
while True:
    Quux()
    if not Fizz():
        break

(If Buzz's only effect is supposed to be returning execution to Quux, don't have a Buzz at all and just return.)

Upvotes: 1

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