I have heard of this many times but @berin was the one friend who made me try it at last.
Inside yoursketchbook/libraries
folder (Processing/libraries
on Mac and Windows) you can have a site-packages
folder containing “Python packages” with modules (.py files) that can be imported by any of your sketches (without having to add them as tabs).
libraries/site-packages/my_lib
|_ __init__.py (can be an empty file)
|_ a_module.py (name them as you wish...)
|_ b_module.py
Then you can use inside your sketch:
from my_lib import a_module, b_module
# or any other normal Python import-happy ways of importing stuff
from my_lib.a_module import *
from my_lib import a_module as amod
from my_lib.b_module import my_great_function, MyClass
I hope I have described this correctly and that it may be useful to other people.