readline inside and outside functions

[paul18fr]

Hi

Because of the size of files I'm working on (often more than a billion lines for example), and the number of different types of data to be recorded (specific width and so on), I've been using "with open" + "readline" (without the end "s");

The main difficulty I'm confront is that all "readline" must remain into the core of the program (and I've now more than a thousand lines to take into account all specificities even using functions when it's possible). Does it make sense to envisage continuing using "readline" into functions and then returning to the core of the program (? if so, how to proceed?

Thanks for your feedback