Holding until next value change

[Arshpreet Singh]

On Saturday, 20 August 2016 11:38:03 UTC+5:30, Steve D'Aprano  wrote:

> state = ignore_negative  # DON'T call the function yet
> for value in main_call():
>     print(value)  # for testing
>     if state(value):
>         print("changing state")
>         state = TABLE[state]

Above code works at some extent but after few minutes of running it
returns and exists by printing 'None' on screen. Let me tell that
main_call() generator spits out values like one more each second after
going through some sort of heavy calculations(but even 50% of RAM is
available) it exits by printing 'None' on screen. Is it some kind of recursion problem?